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1

Equation of state of wet granular matter.  

PubMed

An expression for the near-contact pair correlation function of D -dimensional weakly polydisperse hard spheres is presented, which arises from elementary free-volume arguments. Its derivative at contact agrees very well with our simulations for D=2 . For jammed states, the expression predicts that the number of exact contacts is equal to 2D, in agreement with established simulations. When the particles are wetted, they interact by the formation and rupture of liquid capillary bridges. Since formation and rupture events of capillary bonds are well separated in configuration space, the interaction is hysteretic with a characteristic energy loss Ecb. The pair correlation is strongly affected by this capillary interaction depending on the liquid-bond status of neighboring particles. A theory is derived for the nonequilibrium probability currents of the capillary interaction which determines the pair correlation function near contact. This finally yields an analytic expression for the equation of state, P=P(N/V,T), of wet granular matter for D=2, valid in the complete density range from gas to jamming. Driven wet granular matter exhibits a van der Waals-like unstable branch at granular temperatures Tgranular droplets reported for the free cooling of one-dimensional wet granular matter [A. Fingerle and S. Herminghaus, Phys. Rev. Lett. 97, 078001 (2006)], and extends the effect to higher dimensional systems. Since the limiting case of sticky bonds, Ecb>T, is of relevance for aggregation in general, simulations have been performed which show very good agreement with the theoretically predicted coordination K of capillary bonds as a function of the bond length scrit. This result implies that particles that stick at the surface, scrit=0, form isostatic clusters. An extension of the theory in which the bridge coordination number K plays the role of a self-consistent mean-field is proposed. PMID:18351849

Fingerle, A; Herminghaus, S

2008-01-22

2

Phase diagram of wet granular matter under vertical vibrations  

NASA Astrophysics Data System (ADS)

The phase diagram of vertically vibrated wet granular matter is investigated by both experiments and simulations. We find a critical point where the coexistence (C) regime of the fluid (F) and gas (G) phases terminates. The energy driven F-C transition is found to scale with the rupture energy of a liquid bridge if the corresponding vibration amplitude(A) is less than particle diameter(d). This is in good agreement with our simulations. Close to the F-G transition line, the variation of the size of the gas bubble with vibration amplitude shows a hysteretic behavior. Within the hysteresis loop, we observe temporary gas bubbles with strong fluctuations in size. The F-G boundary is shown to have an interfacial tension and non-trivial wetting behavior at container walls. Focusing on the solid (S)- F transition line, we find that the fluidization is a surface melting process. This is demonstrated by detecting the mobility of ruby tracers utilizing ruby fluorescence. This as well agrees with our simulation results.

Huang, Kai; Roeller, Klaus; Herminghaus, Stephan

2009-03-01

3

Foam-film-stabilized liquid bridge networks in evaporative lithography and wet granular matter.  

PubMed

Evaporative lithography using latex particle templates is a novel approach for the self-assembly of suspension-dispersed nanoparticles into ordered microwire networks. The phenomenon that drives the self-assembly process is the propagation of a network of interconnected liquid bridges between the template particles and the underlying substrate. With the aid of video microscopy, we demonstrate that these liquid bridges are in fact the border zone between the underlying substrate and foam films vertical to the substrate, which are formed during the evaporation of the liquid from the suspension. The stability of the foam films and thus the liquid bridge network stability are due to the presence of a small amount of surfactant in the evaporating solution. We show that the same type of foam-film-stabilized liquid bridge network can also propagate in 3D clusters of spherical particles, which has important implications for the understanding of wet granular matter. PMID:23534699

Vakarelski, Ivan U; Marston, Jeremy O; Thoroddsen, Sigurdur T

2013-04-11

4

Erosion dynamics of a wet granular medium  

NASA Astrophysics Data System (ADS)

Liquid may give strong cohesion properties to a granular medium, and confer a solidlike behavior. We study the erosion of a fixed circular aggregate of wet granular matter subjected to a flow of dry grains inside a half-filled rotating drum. During the rotation, the dry grains flow around the fixed obstacle. We show that its diameter decreases linearly with time for low liquid content, as wet grains are pulled out of the aggregate. This erosion phenomenon is governed by the properties of the liquids. The erosion rate decreases exponentially with the surface tension while it depends on the viscosity to the power -1. We propose a model based on the force fluctuations arising inside the flow, explaining both dependencies: The capillary force acts as a threshold and the viscosity controls the erosion time scale. We also provide experiments using different flowing grains, confirming our model.

Lefebvre, Gautier; Jop, Pierre

2013-09-01

5

Polydirectional Stability of Granular Matter  

NASA Astrophysics Data System (ADS)

We investigate jammed granular matter in a slowly rotating drum partially filled with granular material and find a state of polydirectional stability. In this state, the material responds elastically to small stresses in a wide angular interval while it responds by plastic deformation when subjected to small stresses outside this interval of directions. We describe the evolution of the granulate by means of a rate equation and find quantitative agreement with the experiment. The state of polydirectional stability complements the fragile state, where the material responds elastically to small applied stresses only in a certain direction but even very small stresses in any other direction would lead to plastic deformations. Similar to fragile matter, polydirectionally stable matter is created in a dynamic process by self-organization.

Zimber, Fabian; Kollmer, Jonathan E.; Pöschel, Thorsten

2013-10-01

6

Characterizing the rheology of fluidized granular matter  

NASA Astrophysics Data System (ADS)

In this study we characterize the rheology of fluidized granular matter subject to secondary forcing. Our approach consists of first fluidizing granular matter in a drum half filled with grains via simple rotation and then superimposing oscillatory shear perpendicular to the downhill flow direction. The response of the system is mostly linear, with a phase lag between the grain motion and the oscillatory forcing. The rheology of the system can be well characterized by the GDR MiDi model if the system is forced with slow oscillations. The model breaks down when the forcing time scale becomes comparable to the characteristic time for energy dissipation in the flow.

Desmond, Kenneth W.; Villa, Umberto; Newey, Mike; Losert, Wolfgang

2013-09-01

7

Motility of small nematodes in wet granular media  

NASA Astrophysics Data System (ADS)

The motility of the worm nematode Caenorhabditis elegans is investigated in shallow, wet granular media as a function of particle size dispersity and area density (phi). Surprisingly, we find that the nematode's propulsion speed is enhanced by the presence of particles in a fluid and is nearly independent of area density. The undulation speed, often used to differentiate locomotion gaits, is significantly affected by the bulk material properties of wet mono- and polydisperse granular media for phi>=0.55. This difference is characterized by a change in the nematode's waveform from swimming to crawling in dense polydisperse media only. This change highlights the organism's adaptability to subtle differences in local structure and response between monodisperse and polydisperse media.

Juarez, G.; Lu, K.; Sznitman, J.; Arratia, P. E.

2010-11-01

8

Erosion of a wet/dry granular interface  

NASA Astrophysics Data System (ADS)

To model the dynamic of landslides, the evolution of the interface between the erodible ground and the flowing material is still studied experimentally or numerically (ie. Mangeney et al. 2010, Iverson 2012). In some cases, the basal material is more cohesive than the flowing one. Such situation arises for example due to cementation or humidity. What are the exchange rates between these phases? What is the coupling between the evolution of the interface and the flow? We studied the erosion phenomenon and performed laboratory experiments to focus on the interaction between a cohesive unsaturated granular material and a dry granular flow. Both materials were spherical grains, the cohesion being induced by adding a given mass of liquid to the grains. Two configurations were explored: a circular aggregate submitted to a dry flow in a rotating drum, and a granular flow eroding a wet granular pile. First, we focused on the influence of the cohesion, controlled by the liquid properties, such as the surface tension and the viscosity. Then the flow characteristics were modified by varying the grain size and density. These results allowed us to present a model for the erosion mechanisms, based on the flow and fluid properties. The main results are the need to take into account the whole probability distribution the stress applied on the wet grains and that both the surface tension and the viscosity are important since they play a different roles. The latter is mainly responsible of the time scale of the dynamic of a wet grain, while the former acts as a threshold on the force distribution. In the second configuration, we could also control the inclination of the slope. This system supported the previous model and moreover revealed an interface instability, leading the formation of steep steps, which is a reminiscence of the cyclic-steps observed during river-channel incision (Parker and Izumi 2000). We will present the dynamics of such granular steps. [1] Mangeney, A., O. Roche, O. Hungr, N. Mangold, G. Faccanoni, and A. Lucas (2010), Erosion and mobility in granular collapse over sloping beds, J. Geophys. Res., 115, F03040, doi:10.1029/2009JF001462. [2] Iverson, R. M. (2012), Elementary theory of bed-sediment entrainment by debris flows and avalanches, J. Geophys. Res., 117, F03006, doi:10.1029/2011JF002189. [3] Parker G.and Izumi N., Purely erosional cyclic and solitary steps created by flow over a cohesive bed, J. Fluid Mech. (2000), vol. 419, pp. 203-238.

Jop, Pierre; Lefebvre, Gautier

2013-04-01

9

Motility of small nematodes in disordered wet granular media  

NASA Astrophysics Data System (ADS)

Organisms that evolve within complex fluidic environments often develop unique methods of locomotion that allow them to exploit the properties of the media. In this talk, we present an investigation on the motility of the worm nematode Caenorhabditis elegans in shallow, wet granular media as a function of particle size dispersity and area density (?) using both particle- and nematode-tracking methods. Surprisingly, the nematode's propulsion speed is enhanced by the presence of particles in a fluid and is nearly independent of local area density. The undulation speed, often used to differentiate locomotion gaits, is significantly affected by particle size dispersity for area densities above ?> 0.55, and is characterized by a change in the nematode's waveform from swimming to crawling. This change occurs for dense polydisperse media only and highlights the organism's adaptability to subtle differences in local structure between monodisperse and polydisperse media.

Juarez, Gabriel; Lu, Kevin; Sznitman, Josue; Arratia, Paulo E.

2010-11-01

10

Runaway electrification of friable self-replicating granular matter.  

PubMed

We establish that the nonlinear dynamics of collisions between particles favors the charging of an insulating, friable, self-replicating granular material that undergoes nucleation, growth, and fission processes; we demonstrate with a minimal dynamical model that secondary nucleation produces a positive feedback in an electrification mechanism that leads to runaway charging. We discuss ice as an example of such a self-replicating granular material: We confirm with laboratory experiments in which we grow ice from the vapor phase in situ within an environmental scanning electron microscope that charging causes fast-growing and easily breakable palmlike structures to form, which when broken off may form secondary nuclei. We propose that thunderstorms, both terrestrial and on other planets, and lightning in the solar nebula are instances of such runaway charging arising from this nonlinear dynamics in self-replicating granular matter. PMID:24041221

Cartwright, Julyan H E; Escribano, Bruno; Grothe, Hinrich; Piro, Oreste; Sainz Díaz, C Ignacio; Tuval, Idan

2013-10-01

11

Runaway Electrification of Friable Self-Replicating Granular Matter  

PubMed Central

We establish that the nonlinear dynamics of collisions between particles favors the charging of an insulating, friable, self-replicating granular material that undergoes nucleation, growth, and fission processes; we demonstrate with a minimal dynamical model that secondary nucleation produces a positive feedback in an electrification mechanism that leads to runaway charging. We discuss ice as an example of such a self-replicating granular material: We confirm with laboratory experiments in which we grow ice from the vapor phase in situ within an environmental scanning electron microscope that charging causes fast-growing and easily breakable palmlike structures to form, which when broken off may form secondary nuclei. We propose that thunderstorms, both terrestrial and on other planets, and lightning in the solar nebula are instances of such runaway charging arising from this nonlinear dynamics in self-replicating granular matter.

2013-01-01

12

Time-resolved dynamics of granular matter by random laser emission  

NASA Astrophysics Data System (ADS)

Because of the huge commercial importance of granular systems, the second-most used material in industry after water, intersecting the industry in multiple trades, like pharmacy and agriculture, fundamental research on grain-like materials has received an increasing amount of attention in the last decades. In photonics, the applications of granular materials have been only marginally investigated. We report the first phase-diagram of a granular as obtained by laser emission. The dynamics of vertically-oscillated granular in a liquid solution in a three-dimensional container is investigated by employing its random laser emission. The granular motion is function of the frequency and amplitude of the mechanical solicitation, we show how the laser emission allows to distinguish two phases in the granular and analyze its spectral distribution. This constitutes a fundamental step in the field of granulars and gives a clear evidence of the possible control on light-matter interaction achievable in grain-like system.

Folli, Viola; Ghofraniha, Neda; Puglisi, Andrea; Leuzzi, Luca; Conti, Claudio

2013-07-01

13

The glass and jamming transitions in dense granular matter  

NASA Astrophysics Data System (ADS)

Everyday life tells us that matter acquires rigidity either when it cools down, like lava flows which turn into solid rocks, or when it is compacted, like tablets simply formed by powder compression. As suggested by these examples, solidification is not the sole privilege of crystals but also happens for disordered media such as glass formers, granular media, foams, emulsions and colloidal suspensions. Fifteen years ago the ``Jamming paradigm'' emerged to encompass in a unique framework the glass transition and the emergence of yield stress, two challenging issues in modern condensed matter physics. One must realize how bold this proposal was, given that the glass transition is a finite temperature transition governing the dynamical properties of supercooled liquids, while Jamming is essentially a zero temperature, zero external stress and purely geometric transition which occurs when a given packing of particles reaches the maximum compression state above which particles start to overlap. More recently, the observation of remarkable scaling properties on the approach to jamming led to the conjecture that this zero temperature ``critical point'' could determine the properties of dense particle systems within a region of the parameter space to be determined, which in principle could include thermal and stressed systems. Fifteen years of intense theoretical and experimental work later, what have we learned about Jamming and glassy dynamics? In this paper, we discuss these issues in the light of the experiments we have been conducting with vibrated grains.

Coulais, Corentin; Candelier, Raphaël; Dauchot, Olivier

2013-06-01

14

Size segregation of granular matter in silo discharges  

NASA Astrophysics Data System (ADS)

We present an experimental study of segregation of granular matter in a quasi-two-dimensional silo emptying out of an orifice. Size separation is observed when multisized particles are used with the larger particles found in the center of the silo in the region of fastest flow. We use imaging to study the flow inside the silo and quantitatively measure the concentration profiles of bidisperse beads as a function of position and time. The angle of the surface is given by the angle of repose of the particles, and the flow occurs in a few layers only near the top of this inclined surface. The flowing region becomes deeper near the center of the silo and is confined to a parabolic region centered at the orifice which is approximately described by the kinematic model. The experimental evidence suggests that the segregation occurs on the surface and not in the flow deep inside the silo where velocity gradients also are present. We report the time development of the concentrations of the bidisperse particles as a function of size ratios, flow rate, and the ratio of initial mixture. The qualitative aspects of the observed phenomena may be explained by a void filling model of segregation.

Samadani, Azadeh; Pradhan, A.; Kudrolli, A.

1999-12-01

15

Relevance of wet deposition of organic matter for alpine ecosystems  

NASA Astrophysics Data System (ADS)

In barren, alpine environments, carbon inputs from atmospheric deposition may be very important for ecological processes. Recent findings suggest that atmospheric deposition influences the quality of dissolved organic matter (DOM) in alpine lakes on a global scale. Here, we evaluate the inputs of DOM in atmospheric wet deposition to alpine terrestrial ecosystems, in terms of both quantity and quality. We show that at the Niwot Ridge Long Term Ecological Research Station (Colorado, USA) wet deposition represents a seasonally variable (Figure 1) mass input of organic carbon, depositing on average 6 kg C/ha/yr or roughly 1500 kg C to the Green Lake 4 watershed at Niwot Ridge. Wet deposition is, therefore, a substantial input of dissolved organic carbon (DOC) to the catchment when compared to the annual DOC yield from Green Lake 4, estimated at just over 1800 kg C. In terms of DOM bioavailability for alpine microorganisms, our optical spectroscopic results showing high amounts of amino acid-like fluorescence and low aromaticity suggest that DOM in wet deposition may be particularly labile, especially in the summer months. The heterotrophic processing of this organic carbon input has important implications for the cycling of other nutrients, such as nitrogen, in alpine environments. We have also shown that the sources of DOM in wet deposition include bioaerosols, such as pollen, which represent much of the summer DOC loading. However, relationships with inorganic N and sulfate also suggest that organic pollutants in the atmosphere may have an equally important influence on DOM in wet deposition. Additionally, the quality of wet deposition DOM in the spring is similar to that of dust deposition observed near the Sahara and may be influenced by dust events, as shown from air mass trajectories originating in or near the Colorado Plateau. The seasonality of DOM quality appears to be related to these varying sources and is, therefore, a critical topic for future research.

Mladenov, N.; Williams, M. W.; Schmidt, S. K.; Goss, N. R.; Reche, I.

2011-12-01

16

Regeneration of granular activated carbon with adsorbed trichloroethylene using wet peroxide oxidation.  

PubMed

The objective of this study is to clarify the regeneration of granular activated carbon (GAC) adsorbed trichloroethylene (TCE) using wet peroxide oxidation (WPO). TCE and TOC concentrations decreased during WPO, whereas Cl(-) accumulated in water indicating that TCE was not only decomposed but was also mineralized to Cl(-) and CO(2) using WPO. Regeneration efficiencies (q/q(0)) of GAC regenerated at 150, 165 and 180 degrees C (initial pH 4) were 0.36, 0.45, 0.48, respectively. In addition, regeneration efficiencies of GAC regenerated in the solution of various initial pH (2.5, 3.0, 4.0) at 180 degrees C were 0.71, 0.60, 0.48, respectively. These results suggest that regeneration of GAC is more effective at higher reaction temperature and lower initial pH of the solution. In the repeated regeneration of GAC, the adsorption capacity of GAC for TCE gradually decreased and regeneration efficiency of the regenerated GAC at sixth step was 0.40. The adsorption capacity loss of regenerated GAC is probably due to oxidation of GAC during WPO. PMID:17224174

Okawa, Kiyokazu; Suzuki, Kazuyoshi; Takeshita, Toshihiro; Nakano, Katsuyuki

2007-01-16

17

Effective Reduction of Coulomb Repulsion in Charged Granular Matter  

NASA Astrophysics Data System (ADS)

This paper is an extension to a previous article by Scheffler and Wolfs.6 We study the rate of energy dissipation due to inelastic collisions in a charged granular gas. One observes that the electrostatic repulsion of two particles is effectively reduced by nearest neighbor interactions in a dense granular gas. We study the radial distribution function for dense systems, which leads to a better expression for the reduced energy barrier.

Scheffler, T.; Werth, J.; Wolf, D. E.

2000-04-01

18

Flowers in flour: Avalanches in cohesive granular matter  

NASA Astrophysics Data System (ADS)

We report on the intermittent dynamics of the free surface of a cohesive granular material during a silo discharge. In absence of cohesion, one observes the formation and the growth of a conical crater whose angle is well defined and constant in time. When the cohesion is involved the free surface exhibits a complex dynamics and the crater, resulting from a series of individual avalanches, is no longer axisymmetric. However, in spite of the intermittent behavior of the free surface, the flow rate is observed to remain constant throughout the discharge.

Freyssingeas, E.; Dalbe, M.-J.; Géminard, J.-C.

2011-05-01

19

Jamming during the discharge of granular matter from a silo.  

PubMed

In this work, we present an experimental study of the jamming that stops the free flow of grains from a silo discharging by gravity. When the outlet size is not much bigger than the beads, granular material jams the outlet of the container due to the formation of an arch. Statistical data from the number of grains fallen between consecutive jams are presented. The information that they provide can help one to understand the jamming phenomenon. As the ratio between the size of the orifice and the size of the beads is increased, the probability that an arch blocks the outlet decreases. We show here that there is a power-law divergence of the mean avalanche size for a finite critical radius. Beyond this critical radius, no jamming can occur and the flow is never stopped. The dependence of the arch formation on the shape and the material of the grains has been explored. It has been found that the material properties of the grains do not affect the arch formation probability. On the contrary, the shape of the grains deeply influences it. A simple model to interpret the results is also discussed. PMID:16089524

Zuriguel, Iker; Garcimartín, Angel; Maza, Diego; Pugnaloni, Luis A; Pastor, J M

2005-05-12

20

Mechanisms for Acoustic Absorption in Dry and Weakly Wet Granular Media  

SciTech Connect

The dissipation of an elastic wave in dry and wet glass bead packings is measured using multiple sound scattering. The interplay of a linear viscoelastic loss and a nonlinear frictional one is observed in dry media. The Mindlin model provides a qualitative description of the experiment, but fails to quantitatively account for the data due to grain roughness. In weakly wet media, we find that the dissipation is dominated by a linear viscous loss due to the liquid films trapped at the grain surface asperities. Adding more liquid enables us to form the capillary menisci but does not increase the energy loss.

Brunet, Th.; Jia, X.; Mills, P. [Laboratoire de Physique des Milieux Divises et Interfaces, Universite Paris-Est, CNRS UMR 8108, 77454 Marne-La-Vallee (France)

2008-09-26

21

Particle size distributions by laser diffraction: sensitivity of granular matter strength to analytical operating procedures  

NASA Astrophysics Data System (ADS)

We tested laser diffraction particle size analysis in poorly coherent carbonate platform cataclastic breccias and unfaulted quartz-rich eolian sands, representing low- and high-strength granular materials, respectively. We used two different instruments with different sample dispersion and pumping systems and several wet analytical procedures that included different pump speeds, measurement precision tests with and without sample ultrasonication, and different dispersant liquids. Results of our work indicate that high strength material is not strongly affected by analytical operating procedures, whereas low strength materials are very sensitive to the pump speed, ultrasonication intensity, and measurement run time. To reduce such a data variability, we propose a workflow of analytical tests preliminary to the set up of the most appropriate SOP.

Storti, F.; Balsamo, F.

2010-04-01

22

Electrochemical regeneration of granular activated carbons loaded with phenol and natural organic matter.  

PubMed

The main objective of this study was to assess the performance of electrochemical regeneration of granular activated carbon via a set of bench-scale experiments using different operating conditions in the regeneration of several different activated carbons loaded with phenol or natural organic matter. The regeneration efficiency can be increased by increasing the charge applied, whether this was achieved by an increase in current or regeneration time. The degree of phenol-adsorption saturation did not significantly affect the regeneration efficiencies. The regeneration efficiencies of the various types of phenol-loaded activated carbon were quite similar despite the differences in their conductivity. The activated carbon exhibiting fully reversible adsorption of phenol had slightly higher regeneration efficiencies than those involving partially irreversible adsorption. Electrochemical regeneration of activated carbon is feasible at a laboratory scale as regeneration efficiencies up to 80% were achieved during electrochemical regeneration of phenol-loaded or natural organic matter-loaded activated carbons. PMID:19213463

Narbaitz, R M; Karimi-Jashni, A

2009-01-01

23

Discrete and Continuum Modeling of Energy Transport through Dense Granular Matter  

NASA Astrophysics Data System (ADS)

The transport of stress and energy through dense granular matter (DGM) is of significant importance to a number of applications. Although a significant amount of work has been carried out in order to understand this process, there are still many unknowns, including lack of a generally accepted continuum model, or even lack of understanding of whether such a model should exist. With the goal of making a step towards answering these questions, we carry out large-scale discrete element simulations of DGM exposed to perturbations whose spatial and temporal characteristics are varied independently. The presentation will concentrate on the comparison between the results of the simulations, and of a relatively simple continuum model based on elastic response with damping. This comparison is expected to serve as a basis for further development of continuum models for energy transport through DGM.

Kondic, Lou; Behringer, Robert

2008-11-01

24

Granular activated carbon for removal of organic matter and turbidity from secondary wastewater.  

PubMed

A range of commercial granular activated carbon (GAC) media have been assessed as pretreatment technologies for a downstream microfiltration (MF) process. Media were assessed on the basis of reduction in both organic matter and turbidity, since these are known to cause fouling in MF membranes. Isotherm adsorption analysis through jar testing with supplementary column trials revealed a wide variation between the different adsorbent materials with regard to organics removal and adsorption kinetics. Comparison with previous work using powdered activated carbon (PAC) revealed that for organic removal above 60% the use of GAC media incurs a significantly lower carbon usage rate than PAC. All GACs tested achieved a minimum of 80% turbidity removal. This combination of turbidity and organic removal suggests that GAC would be expected to provide a significant reduction in fouling of a downstream MF process with improved product water quality. PMID:23306264

Hatt, J W; Germain, E; Judd, S J

2013-01-01

25

Removal of Organic Matters and Phenol Compounds from the Waste Water by Using Granular Activated Carbon - Sequence Batch Reactor System  

Microsoft Academic Search

The studies were concerned in removal of organic matters together with phenol compounds from the synthetic waste water by using Granular Activated Carbon-Sequencing Batch Reactor System (GAC-SBR). The synthetic waste water used in this experiment contained glucose as COD about 3,400 mg\\/l and phenol about 1,000 mg\\/I. The maximal phenol and COD absorption abilities of GAC in SBR system were

Suntud Sirianuntapiboon; Soydoa Vinitnantharat; Waree Chamlongras

26

Attractive emulsion droplets probe the phase diagram of jammed granular matter  

PubMed Central

It remains an open question whether statistical mechanics approaches apply to random packings of athermal particles. Although a jamming phase diagram has recently been proposed for hard spheres with varying friction, here we use a frictionless emulsion system in the presence of depletion forces to sample the available phase space of packing configurations. Using confocal microscopy, we access their packing microstructure and test the theoretical assumptions. As a function of attraction, our packing protocol under gravity leads to well-defined jammed structures in which global density initially increases above random close packing and subsequently decreases monotonically. Microscopically, the fluctuations in parameters describing each particle, such as the coordination number, number of neighbors, and local packing fraction, are for all attractions in excellent agreement with a local stochastic model, indicating that long-range correlations are not important. Furthermore, the distributions of local cell volumes can be collapsed onto a universal curve using the predicted k-gamma distribution, in which the shape parameter k is fixed by the polydispersity while the effect of attraction is captured by rescaling the average cell volume. Within the Edwards statistical mechanics framework, this result measures the decrease in compactivity with global density, which represents a direct experimental test of a jamming phase diagram in athermal systems. The success of these theoretical tools in describing yet another class of materials gives support to the much-debated statistical physics of jammed granular matter.

Jorjadze, Ivane; Pontani, Lea-Laetitia; Newhall, Katherine A.; Brujic, Jasna

2011-01-01

27

Injection of granular material  

Microsoft Academic Search

Some civil engineering projects require the injection of granular matter such as sand into the ground. However, granular matter\\u000a resists pumping through tubes and thus it is difficult to inject such matter into the ground. With the help of several methods\\u000a forces and movements of grains were visualized. Force chains and arches in a two dimensional granular matter model were

F. Affeld; P. Debaene; L. Goubergrits

2006-01-01

28

Fiat or Bona Fide Boundary--A Matter of Granular Perspective  

PubMed Central

Background Distinguishing bona fide (i.e. natural) and fiat (i.e. artificial) physical boundaries plays a key role for distinguishing natural from artificial material entities and is thus relevant to any scientific formal foundational top-level ontology, as for instance the Basic Formal Ontology (BFO). In BFO, the distinction is essential for demarcating two foundational categories of material entity: object and fiat object part. The commonly used basis for demarcating bona fide from fiat boundary refers to two criteria: (i) intrinsic qualities of the boundary bearers (i.e. spatial/physical discontinuity, qualitative heterogeneity) and (ii) mind-independent existence of the boundary. The resulting distinction of bona fide and fiat boundaries is considered to be categorial and exhaustive. Methodology/Principal Findings By referring to various examples from biology, we demonstrate that the hitherto used distinction of boundaries is not categorial: (i) spatial/physical discontinuity is a matter of scale and the differentiation of bona fide and fiat boundaries is thus granularity-dependent, and (ii) this differentiation is not absolute, but comes in degrees. By reducing the demarcation criteria to mind-independence and by also considering dispositions and historical relations of the bearers of boundaries, instead of only considering their spatio-structural properties, we demonstrate with various examples that spatio-structurally fiat boundaries can nevertheless be mind-independent and in this sense bona fide. Conclusions/Significance We argue that the ontological status of a given boundary is perspective-dependent and that the strictly spatio-structural demarcation criteria follow a static perspective that is ignorant of causality and the dynamics of reality. Based on a distinction of several ontologically independent perspectives, we suggest different types of boundaries and corresponding material entities, including boundaries based on function (locomotion, physiology, ecology, development, reproduction) and common history (development, heredity, evolution). We argue that for each perspective one can differentiate respective bona fide from fiat boundaries.

Vogt, Lars; Grobe, Peter; Quast, Bjorn; Bartolomaeus, Thomas

2012-01-01

29

Characterization of natural organic matter adsorption in granular activated carbon adsorbers.  

PubMed

The removal of natural organic matter (NOM) from lake water was studied in two pilot-scale adsorbers containing granular activated carbon (GAC) with different physical properties. To study the adsorption behavior of individual NOM fractions as a function of time and adsorber depth, NOM was fractionated by size exclusion chromatography (SEC) into biopolymers, humics, building blocks, and low molecular weight (LMW) organics, and NOM fractions were quantified by both ultraviolet and organic carbon detectors. High molecular weight biopolymers were not retained in the two adsorbers. In contrast, humic substances, building blocks and LMW organics were initially well and irreversibly removed, and their effluent concentrations increased gradually in the outlet of the adsorbers until a pseudo-steady state concentration was reached. Poor removal of biopolymers was likely a result of their comparatively large size that prevented access to the internal pore structure of the GACs. In both GAC adsorbers, adsorbability of the remaining NOM fractions, compared on the basis of partition coefficients, increased with decreasing molecular size, suggesting that increasingly larger portions of the internal GAC surface area could be accessed as the size of NOM decreased. Overall DOC uptake at pseudo-steady state differed between the two tested GACs (18.9 and 28.6 g-C/kg GAC), and the percent difference in DOC uptake closely matched the percent difference in the volume of pores with widths in the 1-50 nm range that was measured for the two fresh GACs. Despite the differences in NOM uptake capacity, individual NOM fractions were removed in similar proportions by the two GACs. PMID:21605887

Velten, Silvana; Knappe, Detlef R U; Traber, Jacqueline; Kaiser, Hans-Peter; von Gunten, Urs; Boller, Markus; Meylan, Sébastien

2011-05-06

30

Energy dissipation in driven granular matter in the absence of gravity.  

PubMed

We experimentally investigate the energy dissipation rate in sinusoidally driven boxes which are partly filled by granular material under conditions of weightlessness. We identify two different modes of granular dynamics, depending on the amplitude of driving, A. For intense forcing, A>A(0), the material is found in the collect-and-collide regime where the center of mass of the granulate moves synchronously with the driven container, while for weak forcing, Agranular material exhibits gaslike behavior. Both regimes correspond to different dissipation mechanisms, leading to different scaling with amplitude and frequency of the excitation and with the mass of the granulate. For the collect-and-collide regime, we explain the dependence on frequency and amplitude of the excitation by means of an effective one-particle model. For both regimes, the results may be collapsed to a single curve characterizing the physics of granular dampers. PMID:23863027

Sack, Achim; Heckel, Michael; Kollmer, Jonathan E; Zimber, Fabian; Pöschel, Thorsten

2013-07-02

31

Evaluating the performance of a turbulent wet scrubber for scrubbing particulate matter.  

PubMed

A turbulent wet scrubber was designed and developed to scrub particulate matter (PM) at micrometer and submicrometer levels from the effluent gas stream of an industrial coal furnace. Experiments were conducted to estimate the particle removal efficiency of the turbulent scrubber with different gas flow rates and liquid heads above the nozzle. Particles larger than 1 microm were removed very efficiently, at nearly 100%, depending upon the flow rate, the concentration of the dust-laden air stream, and the water level in the reservoir Particles smaller than 1 microm were also removed to a greater extent at higher gas flow rates and for greater liquid heads. Pressure-drop studies were also carried out to estimate the energy consumed by the scrubber for the entire range of particle sizes distributed in the carrier gas. A maximum pressure drop of 217 mm H2O was observed for a liquid head of 36 cm and a gas flow rate of 7 m3/min. The number of transfer units (NTU) analysis for the efficiencies achieved by the turbulent scrubber over the range of particles also reveals that the contacting power achieved by the scrubber is better except for smaller particles. The turbulent scrubber is more competent for scrubbing particulate matter, in particular PM2.5, than other higher energy or conventional scrubbers, and is comparable to other wet scrubbers of its kind for the amount of energy spent. Implications: The evaluation of the turbulent scrubber is done to add a novel scrubber in the list of wet scrubbers for industrial applications, yet simple in design, easy to operate, with better compactness, and with high efficiencies at lower energy consumption. Hence the turbulent scrubber can be used to combat particulate from industrial gaseous effluents and also has a scope to absorb gaseous pollutants if the gases are soluble in the medium used for particles capture. PMID:23786141

Lee, Byeong-Kyu; Mohan, B Raj; Byeon, Seung-Hyeok; Lim, Kyung-Soo; Hong, Eun-Pyo

2013-05-01

32

Mixing and segregation of granular matter: multi-lobe formation in time-periodic flows  

NASA Astrophysics Data System (ADS)

We study size segregation in two classes of granular systems in time-periodically forced quasi-two-dimensional tumblers. In dry granular systems (DGS), particles are immersed in air, whereas in liquid granular systems (LGS) or slurries, particles are wholly immersed in a less dense liquid. Experimental results show lobe formation and classical radial segregation, depending on the frequency of the forcing and fill fraction of the system. Both DGS and LGS exhibit similar multi-lobe patterns when subjected to the same forcing. A simple model captures the experimental results and suggests that the symmetry of the forcing plays a crucial role in the emergence of the patterns. Lobes form via a reinforcement mechanism that depends on the period of the regular islands in the Poincaré map. The mechanism can be controlled by changing the forcing period and/or fill fraction.

Fiedor, S. J.; Ottino, J. M.

2005-06-01

33

Granular magnetoresistance in cobalt/poly (3-hexylthiophene, 2, 5-diyl) hybrid thin films prepared by a wet chemical method  

NASA Astrophysics Data System (ADS)

Cobalt/poly (3-hexylthiophene, 2, 5-diyl) (P3HT) hybrid thin films were prepared by a wet chemical method. Their microstructure consists of a nanoscale mixture of a crystalline P3HT matrix, interspersed with amorphous P3HT regions containing the cobalt nanoparticles. Magnetic and transport measurements are consistent with this microstructure and the temperature dependence of the resistance of these hybrid systems is well-fitted (R2=0.9993) to the fluctuation induced tunneling model. Moreover, by applying a magnetic field, a magnetoresistance ratio of 3% was observed in 17 vol % Co hybrid films at 10 K.

Wen, Tianlong; Liu, Dan; Luscombe, Christine K.; Krishnan, Kannan M.

2009-08-01

34

Removal of dissolved organic matter by granular-activated carbon adsorption as a pretreatment to reverse osmosis of membrane bioreactor effluents  

Microsoft Academic Search

The adsorption of dissolved organic matter (DOM) on granular-activated carbon (GAC) as a pretreatment to reverse osmosis (RO) desalination of membrane bioreactor (MBR) effluents was studied in lab- and pilot-scale columns. The pattern and efficiency of DOM adsorption and fate of the hydrophobic (HPO), transphilic (TPI) and hydrophilic (HPI) fractions were characterized, as well as their impact on organic fouling

Shirra Gur-Reznik; Ilan Katz; Carlos G. Dosoretz

2008-01-01

35

Particle dynamics and effective temperature of jammed granular matter in a slowly sheared three-dimensional Couette cell.  

PubMed

We report experimental measurements of particle dynamics on slowly sheared granular matter in a three-dimensional Couette cell. A closely packed ensemble of transparent spherical beads is confined by an external pressure and filled with fluid to match both the density and refractive index of the beads. This allows us to track tracer particles embedded in the system and obtain three-dimensional trajectories [r(t),theta(t),z(t)] as a function of time. We study the probability distribution function of the vertical and radial displacements, finding Gaussian and exponential distributions, respectively. For slow shear rates, the mean-square fluctuations in all three directions are found to be dependent only on the angular displacement of the Couette cell, Delta theta e, (Delta z 2) approximately Delta theta e, (Delta r2) approximately Delta theta e alpha, Delta theta 2 approximately Delta theta e beta, where alpha and beta are constants. With Delta theta e proportional to the time between measurements, the values of the constants, alpha and beta , are found to be subdiffusive and superdiffusive, respectively. ThFe linear relation between (Delta z 2) and angular displacement implies a diffusive process, from which we can calculate an "effective temperature," T eff, in the vertical direction, through a fluctuation-dissipation relation. It is of interest to determine whether these systems can be described by analogous equilibrium statistical mechanics concepts such as "effective temperature" and "compactivity." By studying the dynamics of tracer particles, we find the effective temperature defined by the Stokes-Einstein relation to be independent of the tracer particle characteristic features, such as density and size, and dependent only on the packing density of the system. For slow shear rate, both the diffusivity and mobility of tracer particles are proportional to the shear rate, giving rise to a constant effective temperature, characteristic of the jammed system. We finally discuss the significance of the existence of T eff for a statistical mechanics formulation of granular matter. PMID:18643259

Wang, Ping; Song, Chaoming; Briscoe, Christopher; Makse, Hernán A

2008-06-30

36

A simple wet chemical extraction procedure to characterize soil organic matter (SOM). I. application and recovery rate  

Microsoft Academic Search

The knowledge of soil organic matter (SOM) composition is important for research in soil science. This is why two classical wet chemical extraction procedures were tested and combined to characterize SOM. Twenty?five samples from typical forest and arable soils in Schleswig?Holstein, Northwest Germany, were investigated in the laboratory. Lipids were extracted using a pre?step method. Several polysaccharide fractions were extracted

L. Beyer; C. Wachendorf; C. Koebbemann

1993-01-01

37

Size Distribution of Wet Weather and Dry Weather Particulate Matter Entrained in Combined Flows from an Urbanizing Sewershed  

Microsoft Academic Search

Urban drainage transports a complex and heterogeneous mixture of aqueous-phase chemicals and also solid-phase particulate\\u000a matter (PM). In this study, event-scale particle size distribution (PSD) of wet and dry weather flows are measured, modeled,\\u000a and compared. The flows are generated from a complex urbanizing sewershed (Liguori catchment) in Cosenza, Italy. Results indicate\\u000a PSDs are heterodisperse, ranging from colloidal to sand-size

P. Piro; M. Carbone; G. Garofalo; J. Sansalone

2010-01-01

38

Wet granular walkers and climbers  

NASA Astrophysics Data System (ADS)

We have observed that when a bidisperse mixture of glass beads is moistened by a fluid and shaken sinusoidally in a vertical container, small clusters of beads take off from the surface of the pile and rapidly climb up the container walls against gravity. These self-organized clus- ters are held together and against the wall by liquid capillary bridges, and are led by one large grain with one or more small grains trailing behind. When similar clusters are placed on a horizontally vibrating substrate they self-align and travel horizontally along the axis of vibration with a ratchet-like motion. We report a detailed experimental study performed for the simplest walker system consisting of one large and one small bead, and present a simple model that accounts for the observed behavior. Reference: Z.S. Khan et al.,New J. Phys 13, 053041 (2011).

Khan, Zeina S.; Steinberger, Audrey; Seemann, Ralf; Herminghaus, Stephan

2012-02-01

39

The effect of water temperature on the adsorption equilibrium of dissolved organic matter and atrazine on granular activated carbon  

SciTech Connect

The influence of water temperature on the adsorption of natural dissolved organic matter (DOM) on activated carbon has not been investigated intensively yet. In this study, batch experiments with granular activated carbon (GAC) F300, from bituminous coal, have been carried out at three temperatures (5, 20, 35{sup o} C) using a humic acid model water and different types of surface water (lake, river, canal). Furthermore, the adsorption of an anthropogenic contaminant, atrazine, was quantified in the absence and presence of DOM. The results indicate a significant influence of water temperature on the adsorption equilibrium of DOM and atrazine. Contrary to expectations, DOM and atrazine adsorption in surface water tends to be increased with increasing water temperature, whereas the extent of this effect is dependent on the type and concentration of DOM. Furthermore, the temperature effect on atrazine adsorption is controlled by competition of DOM and atrazine on adsorption sites. Some assumptions are proposed and discussed for explaining the temperature effects observed in the batch studies. 39 refs., 4 figs., 2 tabs.

Bernd Schreiber; Viktor Schmalz; Thomas Brinkmann; Eckhard Worch [Dresden University of Technology, Dresden (Germany). Institute of Water Chemistry

2007-09-15

40

Effect of organic matter on the performance of granular anammox process.  

PubMed

The presence of organic matter (OM) is considered to affect anammox process adversely, while practically wastewaters containing ammonia are not free from OM. In this study, the performance of anammox granules in presence of OM was evaluated under different COD to N ratios. Low OM concentration did not affect ammonia and nitrite removal significantly but improved the total nitrogen removal via denitrifiers. High OM could suppress anammox activity, resulting in a lower ammonia removal. PCR tests revealed that there was a reduction in the number of anammox bacteria and denitrifiers quantity increased when 400mg COD/L influent was applied. A COD to N threshold ratio for anammox inhibition, defined when ammonia removal dropped to 80%, was 3.1, higher than that of flocculent sludge. This study revealed that the coexistence of denitrification and anammox was an effective strategy to treat wastewaters containing high levels of nitrogen and OM. PMID:22342041

Ni, Shou-Qing; Ni, Jian-Yuan; Hu, De-Liang; Sung, Shihwu

2012-02-01

41

A simple wet chemical extraction procedure to characterize soil organic matter (Som): 2. Reproducibility and verification  

Microsoft Academic Search

In a previous communication in this journal, a fractionation scheme of soil organic matter (SOM) was presented (1). The goal of this paper is to discuss the reproducibility and verification of this procedure with an expanded data set of 150 samples. Litter compound analysis (LCA) is appropriate to detect small differences in the decomposition degree at a quantitative level which

L. Beyer; B. Vogt; C. Köbbemann

1996-01-01

42

Enzymatic Hydrolysis and Ethanol Fermentation of High Dry Matter Wet-Exploded Wheat Straw at Low Enzyme Loading  

NASA Astrophysics Data System (ADS)

Wheat straw was pretreated by wet explosion using three different oxidizing agents (H2O2, O2, and air). The effect of the pretreatment was evaluated based on glucose and xylose liberated during enzymatic hydrolysis. The results showed that pretreatment with the use of O2 as oxidizing agent was the most efficient in enhancing overall convertibility of the raw material to sugars and minimizing generation of furfural as a by-product. For scale-up of the process, high dry matter (DM) concentrations of 15-20% will be necessary. However, high DM hydrolysis and fermentation are limited by high viscosity of the material, higher inhibition of the enzymes, and fermenting microorganism. The wet-explosion pretreatment method enabled relatively high yields from both enzymatic hydrolysis and simultaneous saccharification and fermentation (SSF) to be obtained when performed on unwashed slurry with 14% DM and a low enzyme loading of 10 FPU/g cellulose in an industrial acceptable time frame of 96 h. Cellulose and hemicellulose conversion from enzymatic hydrolysis were 70 and 68%, respectively, and an overall ethanol yield from SSF was 68%.

Georgieva, Tania I.; Hou, Xiaoru; Hilstrøm, Troels; Ahring, Birgitte K.

43

Granular Materials  

NSDL National Science Digital Library

This website from the University of California, Santa Barbara explains what granular materials are and UCSB's research in the field. See animations of granular material simulations and other helpful images.

Lois, Gregg

2009-09-16

44

Controlling cohesive forces in granular media  

NASA Astrophysics Data System (ADS)

When adding a small amount of water to a pile of granular matter, e.g., sand heap, close-by grains can be connected by liquid bridges [1]. Thus, the material becomes plastically and can sustain a larger stress as compared to dry sand. Our general aim is to compare the mechanical properties of wet and dry granular media. For this purpose, we use a suspension of micrometer large glass or Latex spheres dispersed in a binary liquid mixture. The suspending water-lutidine(oil) mixture exhibits a lower critical solution temperature leading to a water-oil-like phase separation slightly above ambient temperature. Close to this demixing region, the oil-like phase undergoes a pre-wetting transition on the particle glass surface inducing liquid bridges [2]. Thus, by varying the temperature we can switch the liquid bridges on and off. We will report on our attempts to directly visualize the formation and control of liquid bridges using confocal and non- confocal microscopy. [4pt] [1] M. Scheel, et al., Nature Materials 7, 174 (2008)[0pt] [2] D. Beysens, and D. Esteve, Phys. Rev. Lett. 54, 2123 (1985)

G"Ogelein, Christoph; Schr"Oter, Matthias; Brinkmann, Martin; Herminghaus, Stephan

2009-11-01

45

PREFACE: Granular media  

NASA Astrophysics Data System (ADS)

Granular materials are of great importance to many industrial and natural processes, and thus attract considerable attention over a broad range of disciplines, from engineering to chemical and physical sciences. As their physical properties are different from known thermal systems, they also raise deep basic scientific issues. This special issue of Journal of Physics: Condensed Matter collects together a group of papers from leading researchers in the physics community which discuss recent new findings and ideas introduced in this rapidly evolving field. Although many topics are still not fully developed, the last decade has witnessed an increasing understanding of a variety of theoretical and experimental issues, ranging from the properties of granular packing, stress distribution and force networks to the dynamics and rheology of granular flow, instabilities and jamming; from the statistical mechanics of granular packs, fluids and gases to applications to problems of geophysical and industrial relevance. The papers in this issue provide an introduction to these topics, summarizing the state-of-the-art and addressing some of the many, still open, questions by featuring an up-to-date presentation of new developments. A deeper test of the theories discussed here and an understanding of the new experimental results reported are certainly among the relevant open research directions ahead in this field. I wish to thank all the contributing authors to this special issue of Journal of Physics: Condensed Matter devoted to granular media.

Nicodemi, Mario

2005-06-01

46

WET SOLIDS FLOW ENHANCEMENT  

SciTech Connect

The elastic modulus E of wet granular material was found to be of the order of 0.25 MPa, this value does not compare well with the value predicted for a cubic array of spheres under Hertzian contact were the predicted values were in the order of 250 MPa . The strain-stress behavior of a wet granular media was measured using a split Parfitt tensile tester. In all cases the stress increases linearly with distance until the maximum uniaxial tensile stress is reached. The stress then decreases exponentially with distance after this maximum is reached. The linear region indicates that wet solids behave elastically for stresses below the tensile stresses and can store significant elastic energy. The elastic deformation cannot be explained by analyzing the behavior of individual capillary bridges and requires accounting for the deformation of the solids particles. The elastic modulus of the wet granular material remains unexplained. New information was found to support the experimental finding and a first theory to explain the very small elastic modulus is presented. A new model based on the used of the finite element method is being developed.

Hugo S. Caram; Natalie Foster

1999-03-30

47

Bioturbation and dissolved organic matter enhance contaminant fluxes from sediment treated with powdered and granular activated carbon.  

PubMed

Sediment amendment with activated carbon (AC) is a promising technique for in situ sediment remediation. To date it is not clear whether this technique sufficiently reduces sediment-to-water fluxes of sediment-bound hydrophobic organic chemicals (HOCs) in the presence of bioturbators. Here, we report polychlorobiphenyl (PCB) pore water concentrations, fluxes, mass transfer coefficients, and survival data of two benthic species, for four treatments: no AC addition (control), powdered AC addition, granular AC addition and addition and subsequent removal of GAC (sediment stripping). AC addition decreased mass fluxes but increased apparent mass transfer coefficients because of dissolved organic carbon (DOC) facilitated transport across the benthic boundary layer (BBL). In turn, DOC concentrations depended on bioturbator activity which was high for the PAC tolerant species Asellus aquaticus and low for AC sensitive species Lumbriculus variegatus. A dual BBL resistance model combining AC effects on gradients, DOC facilitated transport and biodiffusion was evaluated against the data and showed how the type of resistance differs with treatment and chemical hydrophobicity. Data and simulations illustrate the complex interplay between AC and contaminant toxicity to benthic organisms and how differences in species tolerance affect mass fluxes from sediment to the water column. PMID:23590290

Kupryianchyk, D; Noori, A; Rakowska, M I; Grotenhuis, J T C; Koelmans, A A

2013-05-02

48

Self-assembled granular towers  

NASA Astrophysics Data System (ADS)

When some water is added to sand, cohesion among the grains is induced. In fact, only 1% of liquid volume respect to the total pore space of the sand is necessary to built impressive sandcastles. Inspired on this experience, the mechanical properties of wet piles and sand columns have been widely studied during the last years. However, most of these studies only consider wet materials with less than 35% of liquid volume. Here we report the spontaneous formation of granular towers produced when dry sand is poured on a highly wet sand bed: The impacting grains stick on the wet grains due to instantaneous liquid bridges created during the impact. The grains become wet by the capillary ascension of water and the process continues, giving rise to stable narrow sand towers. Actually, the towers can reach the maximum theoretical limit of stability predicted by previous models, only expected for low liquid volumes.

Pacheco-Vazquez, Felipe; Moreau, Florian; Vandewalle, Nicolas; Dorbolo, Stephan

2013-03-01

49

A constitutive law for dense granular flows  

Microsoft Academic Search

A continuum description of granular flows would be of considerable help in predicting natural geophysical hazards or in designing industrial processes. However, the constitutive equations for dry granular flows, which govern how the material moves under shear, are still a matter of debate. One difficulty is that grains can behave like a solid (in a sand pile), a liquid (when

Pierre Jop; Yoël Forterre; Olivier Pouliquen

2006-01-01

50

Ameliorating water repellency under turfgrass of contrasting soil organic matter content: Effect of wetting agent formulation and application frequency  

Microsoft Academic Search

Water conservation strategies are being developed in regions of the world expected to experience decreases in water resources due to changing climates. Strategies advocated for improving water-use efficiency may increase the incidence of soil water repellency in sandy-textured soils. We evaluated the effect of soil wetting agent formulation, and application frequency, on water repellency in sandy soil with two contrasting

L. Barton; T. D. Colmer

2011-01-01

51

Granular Rheology  

NASA Astrophysics Data System (ADS)

The drag resistance of a slowly moving body in dense and pre-sheared granular media depends on the size of the object, the direction of motion and the depth of the object beneath the surface. When rescaled, the data shows surprising power-law type behavior, indicating that it should be possible to develop mean-field type models, although these must be very different from Stokes drag for compact objects. Experimental data to guide theoretical models is presented.

Koehler, Stephan

2004-11-01

52

Effect of the crystallization of a solute on the cohesion in granular materials  

Microsoft Academic Search

We study experimentally the macroscopic cohesion of wet granular materials during water evaporation and progressive crystallization of a solute between grains. The samples are wetted granular columns of cylindrical shape subjected to vertical compression tests. The compressive strength allows us to follow the evolution of the material from the capillary cohesion regime to the cemented cohesion regime. Surprisingly, we find

Fabien Soulié; Moulay Saïd El Youssoufi; Jean-Yves Delenne; Charles Voivret; Christian Saix

2007-01-01

53

PREFACE: Dynamics of wetting Dynamics of wetting  

Microsoft Academic Search

Capillary phenomena associated with fluids wetting other condensed matter phases have drawn great scientific interest for hundreds of years; consider the recent bicentennial celebration of Thomas Young's paper on equilibrium contact angles, describing the geometric shape assumed near a three phase contact line in terms of the relevant surface energies of the constituent phases [1]. Indeed, nearly a century has

Gary S. Grest; Gleb Oshanin; Edmund B. Webb III

2009-01-01

54

Overshoot effect in the Janssen granular column: a crucial test for granular mechanics.  

PubMed

We present experimental results on the mechanical behavior of static granular assemblies confined in a vertical column. Our measurements confirm the universal Janssen scaling for the stress saturation curve. We show consequently, in the context of isotropic elasticity, a relation between the Poisson ratio and the granular packing fraction. Moreover, using a systematic study of the overshoot effect created by a top mass equal to the saturation mass, we show behaviors that are reproduced qualitatively by isotropic elastic materials but of a spectacular amplitude in the case of a granular assembly. These experimental results are strong tests for any theory of granular matter. PMID:16241190

Ovarlez, G; Fond, C; Clément, E

2003-06-30

55

Spectroscopic and wet chemical characterization of solid waste organic matter of different age in landfill sites, southern Germany.  

PubMed

Landfill sites are potential sources of hazardous emissions by degradation and transformation processes of waste organic matter. Its chemical composition and microbial degradability are key factors for risk management, after-care, and estimation of potential emissions. The aim of the study is to provide information about composition and extent of transformation of waste organic matter in four landfill sites in Bavaria, Southern Germany by means of (13)C NMR spectroscopy, acid-hydrolyzable carbohydrates, chloroform-methanol extractable lipids, acid-hydrolyzable proteins, and lignin compounds after CuO oxidation. Ten samples of about 20 to 25 yr, 15 to 20 yr, and 5 to 10 yr of deposition each were taken at 2 m depth intervals by grab drilling till 10-m depth. Increasing temperatures from about 15 degrees C at 2-m depth to >40 degrees C at 10-m depth are found at some of the sites, representing optimum conditions for mesophile methane bacteria. Moisture contents of 160 to 310 g kg(-1) (oven dry), however, provide limiting conditions for anaerobic biodecay. Spectroscopic and chemical variables generally indicate a low extent of biodegradation and transformation at all sites despite a considerable heterogeneity of the samples. Independent of the time and depth of deposition more than 50% of the carbohydrate fraction of the waste organic matter provide a high potential for methane emissions and on-site energy production. There was no significant accumulation of long-chain organic and aromatic compounds, and of lignin degradation products even after more than 25 yr of rotting indicating higher extent of decomposition or stabilization of the waste organic matter. Installation of seepage water cleaning and recirculation systems are recommended to increase suboptimal moisture contents with respect to microbial methanogenesis, energy production, and long-term stabilization of municipal solid waste. PMID:18178887

Bäumler, Rupert; Kögel-Knabner, Ingrid

2008-01-04

56

Harnessing the instabilities of soft matter: Dynamically tuning of wetting, assembly and pattern transformation in polymer microstructures  

NASA Astrophysics Data System (ADS)

In this dissertation, we have investigated the fabrication, mechanical instability and applications of two kinds of polymer micro/nano-structures: high-aspect-ratio (HAR) polymer pillar arrays, and periodic porous elastomer membranes. For HAR polymer pillar arrays, we demonstrated the fabrication of high-aspect-ratio (up to 18) polymer micropillars with different shapes and dimensions by replica molding. Capillary force lithography (CFL) is also demonstrated as a simple and flexible method to fabricate microstructures with controlled aspect ratios. Meanwhile, by introducing conventional photoresist SU-8, CFL is successfully coupled with photolithography and used to create hierarchical 2D or 3D structures, which greatly expand the capability of current capillary force lithography. The mechanical stability of HAR structures with varied materials and different aspect ratio, density and shape were also studied and the results show that the adhesive forces from environment are the major cause of structure collapsing. When HAR polymer pillars are subjected to different solvents treatment, both capillary force and solvent swelling need to be considered to completely understand the structure instability. On HAR micropillar array, thermoresponsive polymer brushes, poly ( N-isopropylacrylamide) (PNIPAAm), were selectively grafted at different locations for dynamically tuning surface wetting or pattern assembly. When the temperature changed from 40°C to 20°, depending on the location of polymer brushes, different wetting transitions, either from a composite solid/air state (Cassie state) to a composite solid/liquid state (Hemi-wicking state) or a transition between two Cassie states were observed. Meanwhile, the dynamically tuning of water contact angle enables us to control capillary drying force and thus harness pattern collapse to create superlattice micropatterns. For periodic porous elastomer membrane, a novel pattern transformation effect is discovered due to the mechanical instability of membrane under solvent swelling. To harness this elastic instability, we convectively assemble nanoparticles onto a swollen membrane and capture this dynamic pattern transformation process. By using the nanoparticle film that imprinted with deformed pattern as a master mold, the complex pattern formed by elastic deformation can be transferred into other materials through replica molding, capillary imprinting & selective etching. The unique 3D morphology of the elastic deformation pattern allows us to perform gradient etching, allowing more flexibility to control pattern morphology.

Zhang, Ying

57

Soil organic matter composition in urbic anthrosols in the city of Kiel, NW-Germany, as revealed by wet chemistry and CPMAS 13C-NMR spectroscopy of whole soil samples  

Microsoft Academic Search

In urban environment soil organic matter (SOM) has manifold functions and a tremendous ecological significance. However, little is known about SOM in urbic soils. In six top layers of soils with different age in the city of Kiel at the Baltic Sea, Northwest Germany, the SOM composition was investigated by means of wet chemistry and CPMAS 13C—NMR spectroscopy and compared

L. Beyer; E. Cordsen; H.-P. Blume; U. Schleuss; B. Vogt; Q. Wu

1996-01-01

58

WET SOLIDS FLOW ENHANCEMENT  

SciTech Connect

The yield locus, tensile strength and fracture mechanisms of wet granular materials were studied. The yield locus of a wet material was shifted to the left of that of the dry specimen by a constant value equal to the compressive isostatic stress due to pendular bridges. for materials with straight yield loci, the shift was computed from the uniaxial tensile strength, either measured in a tensile strength tester or calculated from the correlation, and the angle of internal friction of the material. The predicted shift in the yield loci due to different moisture contents compare well with the measured shift in the yield loci of glass beads, crushed limestone, super D catalyst and Leslie coal. Measurement of the void fraction during the shear testing was critical to obtain the correct tensile strength theoretically or experimentally.

Unknown

2001-03-25

59

Day wetting  

Microsoft Academic Search

About 1% of healthy children over the age of 5 years have troublesome daytime wetting. Two-thirds of those who wet by day are reliably dry at night. The problem is more common in girls and is usually the result of urge incontinence. Although the wetting may be exacerbated by giggling and\\/or stress, pure giggle micturition and isolated stress incontinence are

S. R. Meadow

1990-01-01

60

Distribution and disinfection of bacterial loadings associated with particulate matter fractions transported in urban wet weather flows.  

PubMed

Urban runoff is a resource for reuse water. However, runoff transports indicator and pathogenic organisms which are mobilized from sources of fecal contamination. These organisms are entrained with particulate matter (PM) that can serve as a mobile substrate for these organisms. Within a framework of additional treatment for reuse of treated runoff which requires the management of PM inventories in unit operations and drainage systems there is a need to characterize organism distributions on PM and the disinfection potential thereof. This study quantifies total coliform, Escherichia coli, fecal streptococcus, and enterococcus generated from 25 runoff events. With the ubiquity and hetero-dispersivity of PM in urban runoff this study examines organism distributions for suspended, settleable and sediment PM fractions differentiated based on PM size and transport functionality. Hypochlorite is applied in batch to elaborate inactivation of PM-associated organisms for each PM fraction. Results indicate that urban runoff bacterial loadings of indicator organisms exceed U.S. wastewater reuse, recreational contact, and Australian runoff reuse criteria as comparative metrics. All monitored events exceeded the Australian runoff reuse criteria for E. coli in non-potable residential and unrestricted access systems. In PM-differentiated events, bacteriological mobilization primarily occurred in the suspended PM fraction. However, sediment PM shielded PM-associated coliforms at all hypochlorite doses, whereas suspended and settleable PM fractions provide less shielding resulting in higher inactivation by hypochlorite. PMID:22244969

Dickenson, Joshua A; Sansalone, John J

2011-12-24

61

Dynamics of wetting  

Microsoft Academic Search

Capillary phenomena associated with fluids wetting other condensed matter phases have drawn great scientific interest for hundreds of years; consider the recent bicentennial celebration of Thomas Young's paper on equilibrium contact angles, describing the geometric shape assumed near a three phase contact line in terms of the relevant surface energies of the constituent phases [1]. Indeed, nearly a century has

Gary S Grest; Gleb Oshanin; Edmund B Webb

2009-01-01

62

PREFACE: Dynamics of wetting Dynamics of wetting  

NASA Astrophysics Data System (ADS)

Capillary phenomena associated with fluids wetting other condensed matter phases have drawn great scientific interest for hundreds of years; consider the recent bicentennial celebration of Thomas Young's paper on equilibrium contact angles, describing the geometric shape assumed near a three phase contact line in terms of the relevant surface energies of the constituent phases [1]. Indeed, nearly a century has passed since the seminal papers of Lucas and Washburn, describing dynamics of capillary imbibition [2, 3]. While it is generally appreciated that dynamics of fluid wetting processes are determined by the degree to which a system is out of capillary equilibrium, myriad complications exist that challenge the fundamental understanding of dynamic capillary phenomena. The topic has gathered much interest from recent Nobel laureate Pierre-Gilles de Gennes, who provided a seminal review of relevant dissipation mechanisms for fluid droplets spreading on solid surfaces [4] Although much about the dynamics of wetting has been revealed, much remains to be learned and intrinsic technological and fundamental interest in the topic drives continuing high levels of research activity. This is enabled partly by improved experimental capabilities for resolving wetting processes at increasingly finer temporal, spatial, and chemical resolution. Additionally, dynamic wetting research advances via higher fidelity computational modeling capabilities, which drive more highly refined theory development. The significance of this topic both fundamentally and technologically has resulted in a number of reviews of research activity in wetting dynamics. One recent example addresses the evaluation of existing wetting dynamics theories from an experimentalist's perspective [5]. A Current Opinion issue was recently dedicated to high temperature capillarity, including dynamics of high temperature spreading [6]. New educational tools have recently emerged for providing instruction in wetting dynamics and the broader field of fluid dynamics [7-9]. Such an active field requires an occasional collective examination of current research to highlight both recent successes and remaining challenges. Herein, we have collected a range of articles to illustrate the broad nature of research associated with understanding dynamics of moving condensed matter three phase contact lines. Despite the breadth of topics examined, certain unifying themes emerge. The role of the substrate surface is critical in determining kinetics of wetting; this is evidenced by the attention given to this in articles herein. McHale et al investigate the role of surface topography on wetting kinetics and how its effect can be incorporated in existing theories describing contact line dynamics. Moosavi et al examine surface topography effects via a mesoscopic hydrodynamics approach. The capillary driven motion of fluid through structures on a surface bears tremendous importance for microfluidics studies and the emerging field of nanofluidics. Blow et al examine this phenomena for liquid imbibition into a geometric array of structures on a solid surface, while Shen et al analyze the effects of surface temperature during boiling and non-boiling conditionson droplet impingement dynamics. Finally, Pesika et al discover a wonderful world of smart surfaces, like gecko adhesion pads. A number of papers utilize computational modeling to explore phenomena underlying wetting dynamics and to consider relevant mechanisms in terms of existing theory for contact line dynamics. Winter et al utilize Monte Carlo simulation techniques and thermodynamic integration methods to test classical theory describing heterogeneous nucleation at a wall near a wetting transition. Qian et al briefly review the Onsager principle of minimum energy dissipation underlying many descriptions of dissipative systems; they then provide a variational approach description of hydrodynamics of moving contact lines and demonstrate the validity of their continuum model via comparison with molecular dynamics simulations.Bertrand et al

Grest, Gary S.; Oshanin, Gleb; Webb, Edmund B., III

2009-11-01

63

Vibration-induced liquefaction of granular suspensions.  

PubMed

We investigate the mechanical behavior of granular suspensions subjected to coupled vibrations and shear. At high shear stress, whatever the mechanical vibration energy and bead size, the system behaves like a homogeneous suspension of hard spheres. At low shear stress, in addition to a dependence on bead size, vibration energy drastically influences the viscosity of the material that can decrease by more than 2 orders of magnitude. All experiments can be rationalized by introducing a hydrodynamical Peclet number defined as the ratio between the lubrication stress induced by vibrations and granular pressure. The behavior of vibrated wet and dry granular materials can then be unified by assimilating the hookean stress in dry media to the lubrication stress in suspensions. PMID:23003094

Hanotin, C; Kiesgen de Richter, S; Marchal, P; Michot, L J; Baravian, C

2012-05-07

64

Vibration-induced Liquefaction of Granular Suspensions  

NASA Astrophysics Data System (ADS)

We investigate the mechanical behavior of granular suspensions subjected to coupled vibrations and shear. At high shear stress, whatever the mechanical vibration energy and bead size, the system behaves like a homogeneous suspension of hard spheres. At low shear stress, in addition to a dependence on bead size, vibration energy drastically influences the viscosity of the material that can decrease by more than 2 orders of magnitude. All experiments can be rationalized by introducing a hydrodynamical Peclet number defined as the ratio between the lubrication stress induced by vibrations and granular pressure. The behavior of vibrated wet and dry granular materials can then be unified by assimilating the Hookean stress in dry media to the lubrication stress in suspensions.

Hanotin, C.; Kiesgen de Richter, S.; Marchal, P.; Michot, L. J.; Baravian, C.

2012-05-01

65

Jamming in granular polymers.  

PubMed

We examine the jamming transition in a two-dimensional granular polymer system using compressional simulations. The jamming density ?(c) decreases with increasing length of the granular chain due to the formation of loop structures, in excellent agreement with recent experiments. The jamming density can be further reduced in mixtures of granular chains and granular rings, also as observed in experiment. We show that the nature of the jamming in granular polymer systems has pronounced differences from the jamming behavior observed for polydisperse two-dimensional disk systems at point J. This result provides further evidence that there is more than one type of jamming transition. PMID:21867160

Lopatina, L M; Olson Reichhardt, C J; Reichhardt, C

2011-07-18

66

Stress transmission and incipient yield flow in dense granular materials  

Microsoft Academic Search

Jammed granular matter transmits stresses non-uniformly like no conventional solid, especially when it is on the verge of failure. Jamming is caused by self-organization of granular matter under external loads, often giving rise to networks of force chains that support the loads non-uniformly. An ongoing debate in the literature concerns the correct way to model the static stress field in

Raphael Blumenfeld

2010-01-01

67

Granular Volcano Group  

NSDL National Science Digital Library

Sébastien Dartevelle, a Ph.D. student at Michigan Tech, created this Web site devoted to the understanding of "granular flows, granular processes, fluid dynamic, supercomputer modeling, and grain-size analysis of Volcanology, Geophysics, and Physics." Providing challenging materials in an accurate and simple manner, students can easily learn about topics including granular theory and granular medium. Users will find essential facts about viscous phenomenon in the newly added link, All I Wanna Know 'bout Viscous Stress. Educators and students can view the Plinian Cloud simulations. The author also provides mathematical equations, atmospheric profiles, and much more.

Dartevelle, Sãâ©bastien

2007-10-19

68

Granular Volcano Group  

NSDL National Science Digital Library

S'bastien Dartevelle, a Ph.D. student at Michigan Tech, created this Web site devoted to the understanding of "granular flows, granular processes, fluid dynamic, supercomputer modeling, and grain-size analysis of Volcanology, Geophysics, and Physics." Providing challenging materials in an accurate and simple manner, students can easily learn about topics including granular theory and granular medium. Users will find essential facts about viscous phenomenon in the newly added link, All I Wanna Know 'bout Viscous Stress. Educators and students can view the Plinian Cloud simulations. The author also provides mathematical equations, atmospheric profiles, and much more.

69

PREFACE: Wetting: introductory note  

NASA Astrophysics Data System (ADS)

The discovery of wetting as a topic of physical science dates back two hundred years, to one of the many achievements of the eminent British scholar Thomas Young. He suggested a simple equation relating the contact angle between a liquid surface and a solid substrate to the interfacial tensions involved [1], ?lg cos ? = ?sg - ?sl (1) In modern terms, ? denotes the excess free energy per unit area of the interface indicated by its indices, with l, g and s corresponding to the liquid, gas and solid, respectively [2]. After that, wetting seems to have been largely ignored by physicists for a long time. The discovery by Gabriel Lippmann that ? may be tuned over a wide range by electrochemical means [3], and some important papers about modifications of equation~(1) due to substrate inhomogeneities [4,5] are among the rare exceptions. This changed completely during the seventies, when condensed matter physics had become enthusiastic about critical phenomena, and was vividly inspired by the development of the renormalization group by Kenneth Wilson [6]. This had solved the long standing problem of how to treat fluctuations, and to understand the universal values of bulk critical exponents. By inspection of the critical exponents of the quantities involved in equation~(1), John W Cahn discovered what he called critical point wetting: for any liquid, there should be a well-defined transition to complete wetting (i.e., ? = 0) as the critical point of the liquid is approached along the coexistence curve [7]. His paper inspired an enormous amount of further work, and may be legitimately viewed as the entrance of wetting into the realm of modern physics. Most of the publications directly following Cahn's work were theoretical papers which elaborated on wetting in relation to critical phenomena. A vast amount of interesting, and in part quite unexpected, ramifications were discovered, such as the breakdown of universality in thin film systems [8]. Simultaneously, a number of very specific and quantitative predictions were put forward which were aimed at direct experimental tests of the developed concepts [9]. Experimentally, wetting phenomena proved to be a rather difficult field of research. While contact angles seem quite easy to measure, deeper insight can only be gained by assessing the physical properties of minute amounts of material, as provided by the molecularly thin wetting layers. At the same time, the variations in the chemical potential relevant for studying wetting transitions are very small, such that system stability sometimes poses hard to solve practical problems. As a consequence, layering transitions in cryogenic systems were among the first to be thoroughly studied [10] experimentally, since they require comparably moderate stability. First-order wetting transitions were not observed experimentally before the early nineties, either in (cryogenic) quantum systems [11,12] or in binary liquid mixtures [13,14]. The first observation of critical wetting, a continuous wetting transition, in 1996 [15] was a major breakthrough [16]. In the meantime, a detailed seminal paper by Pierre Gilles de Gennes published in 1985 [17] had spurred a large number of new research projects which were directed to wetting phenomena other than those related to phase transitions. More attention was paid to non-equilibrium physics, as it is at work when oil spreads over a surface, or a liquid coating beads off (`dewets') from its support and forms a pattern of many individual droplets. This turned out to be an extremely fruitful field of research, and was more readily complemented by experimental efforts than was the case with wetting transitions. It was encouraging to find effects analogous to layering (as mentioned above) in more common systems such as oil films spreading on a solid support [18,19]. Long standing riddles such as the divergence of dissipation at a moving contact line were now addressed both theoretically and experimentally [20,21]. However, the requirements concerning resolution of the measurements, as well as the sta

Herminghaus, S.

2005-03-01

70

Project WET  

NSDL National Science Digital Library

Project WET (Water Education for Teachers) is an international, broad-based water science and education program for formal and informal educators of students in grades K-12. It is part of a larger water resource education program called The Watercourse, l

Deyonge, Sandra C.

2000-01-01

71

Physics of granular media  

Microsoft Academic Search

Granular material, like sand or powders, present many intriguing phenomena like heap formation under vibration, size segregation and the emission of density waves. These collective effects have eluded description in terms of continuum descriptions up to now. We show how the granular medium can be modelled by a packing of elastic spheres and simulated via Molecular Dynamics. Dissipation of energy

H. J. Herrmann

1995-01-01

72

Adapting granular materials through artificial evolution  

NASA Astrophysics Data System (ADS)

Over 200 years after Coulomb’s studies, a general connection between the mechanical response of a granular material and the constituents’ shape remains unknown. The key difficulty in articulating this relationship is that shape is an inexhaustible parameter, making its systematic exploration infeasible. Here we show that the role of particle shape can, however, be explored efficiently when granular design is viewed in the context of artificial evolution. By introducing a mutable representation for particle shapes, we demonstrate with computer simulation how shapes can be evolved. As proof of principle, we predicted motifs that link shape to packing stiffness, discovered a particle that produces aggregates that stiffen—rather than weaken—under compression, and verified the results using three-dimensional printing. More generally, our approach facilitates the exploration of the role of arbitrary particle geometry in jammed systems, and invites the discovery and design of granular matter with optimized properties.

Miskin, Marc Z.; Jaeger, Heinrich M.

2013-04-01

73

Adapting granular materials through artificial evolution.  

PubMed

Over 200 years after Coulomb's studies, a general connection between the mechanical response of a granular material and the constituents' shape remains unknown. The key difficulty in articulating this relationship is that shape is an inexhaustible parameter, making its systematic exploration infeasible. Here we show that the role of particle shape can, however, be explored efficiently when granular design is viewed in the context of artificial evolution. By introducing a mutable representation for particle shapes, we demonstrate with computer simulation how shapes can be evolved. As proof of principle, we predicted motifs that link shape to packing stiffness, discovered a particle that produces aggregates that stiffen-rather than weaken-under compression, and verified the results using three-dimensional printing. More generally, our approach facilitates the exploration of the role of arbitrary particle geometry in jammed systems, and invites the discovery and design of granular matter with optimized properties. PMID:23334001

Miskin, Marc Z; Jaeger, Heinrich M

2013-01-20

74

Scaling of the normal coefficient of restitution for wet impacts  

NASA Astrophysics Data System (ADS)

A thorough understanding of the energy dissipation in the dynamics of wet granular matter is essential for a continuum description of natural phenomena such as debris flow, and the development of various industrial applications such as the granulation process. The coefficient of restitution (COR), defined as the ratio between the relative rebound and impact velocities of a binary impact, is frequently used to characterize the amount of energy dissipation associated. We measure the COR by tracing a freely falling sphere bouncing on a wet surface with the liquid film thickness monitored optically. For fixed ratio between the film thickness and the particle size, the dependence of the COR on the impact velocity and various properties of the liquid film can be characterized with the Stokes number, defined as the ratio between the inertia of the particle and the viscosity of the liquid. Moreover, the COR for infinitely large impact velocities derived from the scaling can be analyzed by a model considering the energy dissipation from the inertia of the liquid film.

Müller, Thomas; Gollwitzer, Frank; Krülle, Christof A.; Rehberg, Ingo; Huang, Kai

2013-06-01

75

"Smoking Wet"  

PubMed Central

Reports have suggested that the use of a dangerously tainted form of marijuana, referred to in the vernacular as “wet” or “fry,” has increased. Marijuana cigarettes are dipped into or laced with other substances, typically formaldehyde, phencyclidine, or both. Inhaling smoke from these cigarettes can cause lung injuries. We report the cases of 2 young adults who presented at our hospital with respiratory failure soon after they had smoked “wet” marijuana cigarettes. In both patients, progressive hypoxemic respiratory failure necessitated rescue therapy with extracorporeal membrane oxygenation. After lengthy hospitalizations, both patients recovered with only mild pulmonary function abnormalities. To our knowledge, this is the first 2-patient report of severe respiratory failure and rescue therapy with extracorporeal oxygenation after the smoking of marijuana cigarettes thus tainted. We believe that, in young adults with an unexplained presentation of severe respiratory failure, the possibility of exposure to tainted marijuana cigarettes should be considered.

Gilbert, Christopher R.; Baram, Michael; Cavarocchi, Nicholas C.

2013-01-01

76

Project WET  

NSDL National Science Digital Library

Project WET (Water Education for Teachers) is a nonprofit water education program and publisher for educators and young people ages 5-18. Site features information on its renowned training workshops, where participants receive a collection of over 90 K-12 broad-based water resource activities. Site also includes a catalog of other classroom resources available for purchase. Site also available in Spanish and French.

77

Predictability and granular materials  

NASA Astrophysics Data System (ADS)

Granular materials present a number of challenges to predictability. The classical description of a dense granular material is based on Coulomb friction. For a static array of grains, the Coulomb friction forces are typically underdetermined. If we are to make useful statements about such arrays, we must develop new approaches, including the development of statistical descriptions. Granular materials also show large fluctuations in the local forces. These fluctuations are quite sensitive to small perturbations in the packing geometry of the grains. In the past, they have typically been ignored. However, recent experiments and models are beginning to shed new light on their characteristics. This article briefly reviews some of this new work, and in particular presents experimental results characterizing fluctuations and the role of friction in granular materials.

Behringer, R. P.; Howell, Daniel; Kondic, Lou; Tennakoon, Sarath; Veje, Christian

78

Vortex jamming in superconductors and granular rheology  

NASA Astrophysics Data System (ADS)

We demonstrate that a highly frustrated anisotropic Josephson junction array (JJA) on a square lattice exhibits a zero-temperature jamming transition, which shares much in common with those in granular systems. Anisotropy of the Josephson couplings along the horizontal and vertical directions plays roles similar to normal load or density in granular systems. We studied numerically static and dynamic response of the system against shear, i.e. injection of external electric current at zero temperature. Current-voltage curves at various strength of the anisotropy exhibit universal scaling features around the jamming point much as do the flow curves in granular rheology, shear-stress versus shear-rate. It turns out that at zero temperature the jamming transition occurs right at the isotropic coupling and anisotropic JJA behaves as exotic fragile vortex matter: it behaves as a superconductor (vortex glass) in one direction, whereas it is a normal conductor (vortex liquid) in the other direction even at zero temperature. Furthermore, we find a variant of the theoretical model for the anisotropic JJA quantitatively reproduces universal master flow-curves of the granular systems. Our results suggest an unexpected common paradigm stretching over seemingly unrelated fields—the rheology of soft materials and superconductivity.

Yoshino, Hajime; Nogawa, Tomoaki; Kim, Bongsoo

2009-01-01

79

Wet adhesion and adhesive locomotion of snails on anti-adhesive non-wetting surfaces.  

PubMed

Creating surfaces capable of resisting liquid-mediated adhesion is extremely difficult due to the strong capillary forces that exist between surfaces. Land snails use this to adhere to and traverse across almost any type of solid surface of any orientation (horizontal, vertical or inverted), texture (smooth, rough or granular) or wetting property (hydrophilic or hydrophobic) via a layer of mucus. However, the wetting properties that enable snails to generate strong temporary attachment and the effectiveness of this adhesive locomotion on modern super-slippy superhydrophobic surfaces are unclear. Here we report that snail adhesion overcomes a wide range of these microscale and nanoscale topographically structured non-stick surfaces. For the one surface which we found to be snail resistant, we show that the effect is correlated with the wetting response of the surface to a weak surfactant. Our results elucidate some critical wetting factors for the design of anti-adhesive and bio-adhesion resistant surfaces. PMID:22693563

Shirtcliffe, Neil J; McHale, Glen; Newton, Michael I

2012-05-31

80

Wet Adhesion and Adhesive Locomotion of Snails on Anti-Adhesive Non-Wetting Surfaces  

PubMed Central

Creating surfaces capable of resisting liquid-mediated adhesion is extremely difficult due to the strong capillary forces that exist between surfaces. Land snails use this to adhere to and traverse across almost any type of solid surface of any orientation (horizontal, vertical or inverted), texture (smooth, rough or granular) or wetting property (hydrophilic or hydrophobic) via a layer of mucus. However, the wetting properties that enable snails to generate strong temporary attachment and the effectiveness of this adhesive locomotion on modern super-slippy superhydrophobic surfaces are unclear. Here we report that snail adhesion overcomes a wide range of these microscale and nanoscale topographically structured non-stick surfaces. For the one surface which we found to be snail resistant, we show that the effect is correlated with the wetting response of the surface to a weak surfactant. Our results elucidate some critical wetting factors for the design of anti-adhesive and bio-adhesion resistant surfaces.

Shirtcliffe, Neil J.; McHale, Glen; Newton, Michael I.

2012-01-01

81

Swimming in granular media  

NASA Astrophysics Data System (ADS)

A class of reptiles known as sand swimmers adapts to hot environments by submerging beneath desert sands during the day and so provide a unique probe into the dynamics of intruders in granular beds. To understand the mechanism for swimming in an otherwise solid bed, we study a simple model of periodic contraction and extension of large intruders in a granular bed. Using an event-driven simulation, we find optimal conditions that idealized swimmers must use to critically fluidize a sand bed so that it is rigid enough to support a load when needed, but fluid enough to permit motion with minimal resistance. Swimmers—or other intruders—that agitate the bed too rapidly produce large voids that prevent traction from being achieved, while swimmers that move too slowly cannot travel before the bed resolidifies around them, i.e., the swimmers locally probe the fundamental time scale in a granular packing.

Shimada, Takashi; Kadau, Dirk; Shinbrot, Troy; Herrmann, Hans J.

2009-08-01

82

Biomarker and stable carbon isotope analyses of sedimentary organic matter from Lake Tswaing: evidence for deglacial wetness and early Holocene drought from South Africa  

Microsoft Academic Search

Comparing the organic matter (OM) composition of modern and past lake sediments contributes to the understanding of changes\\u000a in lacustrine environments over time. We investigate modern plant and lake-water samples as well as modern and ancient sediment\\u000a samples from the Tswaing Crater in South Africa using biomarker and stable carbon isotope analyses on bulk OM and specific\\u000a biomarker compounds. The

I. Kristen; H. Wilkes; A. Vieth; K.-G. Zink; B. Plessen; J. Thorpe; T. C. Partridge; H. Oberhänsli

2010-01-01

83

Rainwater Channelization and Infiltration in Granular Media  

NASA Astrophysics Data System (ADS)

We investigate the formation of fingered flow in dry granular media under simulated rainfall using a quasi-2D experimental set-up composed of a random close packing of mono-disperse glass beads. We determine effects of grain diameter and surface wetting properties on the formation and infiltration of water channels. For hydrophilic granular media, rainwater initially infiltrates a shallow top layer of soil creating a uniform horizontal wetting front before instabilities occur and grow to form water channels. For hydrophobic media, rainwater ponds on the soil surface rather than infiltrates and water channels may still occur at a later time when the hydraulic pressure of the ponding water exceeds the capillary repellency of the soil. We probe the kinetics of the fingering instabilities that serve as precursors for the growth and drainage of water channels. We also examine the effects of several different methods on improving rainwater channelization such as varying the level of pre-saturation, modifying the soil surface flatness, and adding superabsorbent hydrogel particles.

Mikhail Cejas, Cesare; Wei, Yuli; Barrois, Remi; Durian, Douglas J.; Dreyfus, Remi

2013-03-01

84

Impact of granular drops  

NASA Astrophysics Data System (ADS)

We investigate the spreading and splashing of granular drops during impact with a solid target. The granular drops are formed from roughly spherical balls of sand mixed with water, which is used as a binder to hold the ball together during free-fall. We measure the instantaneous spread diameter for different impact speeds and find that the normalized spread diameter d/D grows as (tV/D)1/2. The speeds of the grains ejected during the “splash” are measured and they rarely exceed twice that of the impact speed.

Marston, J. O.; Mansoor, M. M.; Thoroddsen, S. T.

2013-07-01

85

Impact of granular drops.  

PubMed

We investigate the spreading and splashing of granular drops during impact with a solid target. The granular drops are formed from roughly spherical balls of sand mixed with water, which is used as a binder to hold the ball together during free-fall. We measure the instantaneous spread diameter for different impact speeds and find that the normalized spread diameter d/D grows as (tV/D)^{1/2}. The speeds of the grains ejected during the "splash" are measured and they rarely exceed twice that of the impact speed. PMID:23944390

Marston, J O; Mansoor, M M; Thoroddsen, S T

2013-07-15

86

Anaerobic Granular Sludge Bioreactor Technology  

Microsoft Academic Search

Anaerobic digestion is a mature wastewater treatment technology, with worldwide application. The predominantly applied bioreactor designs, such as the upflow anaerobic sludge blanket and expanded granular sludge bed, are based on the spontaneous formation of granular sludge. Despite the exploitation of granular reactors at full-scale for more than two decades, the mechanisms of granulation are not completely understood and numerous

Sharon McHugh; Caroline O'Reilly; Thérèse Mahony; Emer Colleran; Vincent O'Flaherty

2003-01-01

87

Microstructure control and wear resistance of grain boundary allotriomorphic ferrite\\/granular bainite duplex steel  

Microsoft Academic Search

The abrasive wear resistance of a hot-rolled and air-cooled high strength low alloy (HSLA) steel with grain boundary allotriomorphic ferrite\\/granular bainite (FGBA\\/Bg) duplex microstructure was investigated by comparison with the granular bainitic steel with the same composition and other two commercial HSLA ferrite\\/pearlite steels. The results from the wet sand\\/rubber wheel abrasion test show that the FGBA\\/Bg duplex steel possesses

Pingguang Xu; Bingzhe Bai; Fuxing Yin; Hongsheng Fang; Kotobu Nagai

2004-01-01

88

EVALUATION OF WET AND DRY DISTILLERS GRAINS AND WET AND DRY CORN GLUTEN FEEDS FOR RUMINANTS  

Microsoft Academic Search

Summary Eight trials were conducted to evaluate wet and dry distillers grains (WDG and DDG) and wet and dry corn gluten feeds (WCGF and DCGF) as feed sources for cattle and sheep. Data from in situ trial 1 indicated that dry matter (DM) of WCGF and DCGF disappeared at .a faster rate (P<.05) than that of WDG or DDG. In

J. L. Firkins; L. L. Berger; G. C. Fahey

2010-01-01

89

Granular flow over inclined channels with constrictions  

NASA Astrophysics Data System (ADS)

Study of granular flows down inclined channels is essential in understanding the dynamics of natural grain flows like landslides and snow avalanches. As a stepping stone, dry granular flow over an inclined channel with a localised constriction is investigated using both continuum methods and particle simulations. Initially, depth-averaged equations of motion (Savage & Hutter 1989) containing an unknown friction law are considered. The shallow-layer model for granular flows is closed with a friction law obtained from particle simulations of steady flows (Weinhart et al. 2012) undertaken in the open source package Mercury DPM (Mercury 2010). The closed two-dimensional (2D) shallow-layer model is then width-averaged to obtain a novel one-dimensional (1D) model which is an extension of the one for water flows through contraction (Akers & Bokhove 2008). Different flow states are predicted by this novel one-dimensional theory. Flow regimes with distinct flow states are determined as a function of upstream channel Froude number, F, and channel width ratio, Bc. The latter being the ratio of the channel exit width and upstream channel width. Existence of multiple steady states is predicted in a certain regime of F - Bc parameter plane which is in agreement with experiments previously undertaken by (Akers & Bokhove 2008) and for granular flows (Vreman et al. 2007). Furthermore, the 1D model is verified by solving the 2D shallow granular equations using an open source discontinuous Galerkin finite element package hpGEM (Pesch et al. 2007). For supercritical flows i.e. F > 1 the 1D asymptotics holds although the two-dimensional oblique granular jumps largely vary across the converging channel. This computationally efficient closed 1D model is validated by comparing it to the computationally more expensiveaa three-dimensional particle simulations. Finally, we aim to present a quasi-steady particle simulation of inclined flow through two rectangular blocks separated by a gap, investigate the channel formed by the dead zones and compare it with our analytical calculations. REFERENCES 1. Akers, B. & Bokhove, O. 2008 Hydraulic flow through a channel contraction: Multiple steady states. Physics of fluids 20 (056601), 056601. 2. Mercury 2010 http://www2.msm.ctw.utwente.nl/athornton/md/ . 3. Pesch, L., Bell, A., Sollie, H., Ambati, V.R., Bokhove, O. & Van der Vegt, J.J.W. 2007 hpGEM—a software framework for discontinuous Galerkin finite element methods. ACM Transactions on Mathematical Software (TOMS) 33 (4), 23. 4. Savage, SB & Hutter, K. 1989 The motion of a finite mass of granular material down a rough incline. Journal of Fluid Mechanics 199 (1), 177-215. 5. Vreman, AW, Al-Tarazi, M., Kuipers, JAM, van Sint Annaland, M. & Bokhove, O. 2007 Supercritical shallow granular flow through a contraction: experiment, theory and simulation. Journal of Fluid Mechanics 578 (1), 233-269. 6. Weinhart, T., Thornton, A.R., Luding, S. & Bokhove, O. 2012 Closure relations for shallow granular flows from particle simulations. Granular Matter 14 (4), 531-552.

Tunuguntla, Deepak; Weinhart, Thomas; Thornton, Anthony; Bokhove, Onno

2013-04-01

90

Granular Dynamics during Impact  

NASA Astrophysics Data System (ADS)

In this work, we study the impact of a projectile onto a bed of 3 mm grains immersed in an index-matched fluid. Using a laser sheet scanning technique, a high speed camera, and particle tracking, we can measure the trajectory of each grain throughout an impact event. We characterize the bulk and microscopic dynamics within the granular material as a function of initial sample preparation, specifically applying a uniaxial prestrain to the sample. We find that small changes in sample preparation lead to drastic departures from the universal depth scaling seen in previous studies of shallow granular impacts. By examining the nonaffine motion within the system, we propose the effect is due to different loading and buckling of force chains within the system.

Nordstrom, Kerstin; Lim, Emily; Harrington, Matt; Losert, Wolfgang

2013-03-01

91

Large granular lymphocyte leukemia  

Microsoft Academic Search

Clonal diseases of large granular lymphocytes (LGLs) represent a spectrum of clinically rare lymphoproliferative malignancies\\u000a arising from either mature T-cell (CD3+) or natural killer (NK)-cell (CD3?) lineages. The clinical behavior of these disorders ranges from indolent to very aggressive. Patients with symptomatic indolent\\u000a T-cell or NK-cell LGL leukemia are usually treated with immunosuppressive therapies; in contrast, aggressive T-cell or NK-cell

Lubomir Sokol; Thomas P. Loughran

2007-01-01

92

Cohesive granular texture  

Microsoft Academic Search

We investigate the textural properties of cohesive 2D granular packings simulated by means of the molecular dynamics and contact\\u000a dynamics methods involving simple contact laws with adhesion. We find that, while tensile forces appear naturally in response\\u000a to external tensile loading, they appear only for a strong adhesion when the applied load is compressive in all directions.\\u000a We introduce an

F. Radjaï; I. Preechawuttipong; R. Peyroux

2001-01-01

93

Fluctuations in Granular Gases  

Microsoft Academic Search

A driven granular material, e.g. a vibrated box full of sand, is a stationary system which may be very far from equilibrium.\\u000a The standard equilibrium statistical mechanics is therefore inadequate to describe fluctuations in such a system. Here we\\u000a present numerical and analytical results concerning energy and injected power fluctuations. In the first part we explain how\\u000a the study of

A. Barrat; A. Puglisi; E. Trizac; P. Visco; F. van Wijland

2008-01-01

94

Flash weakening is limited by granular dynamics  

NASA Astrophysics Data System (ADS)

We measured the steady-state friction coefficient of granite over a wide range of sliding velocities and pressures. We observed considerable weakening, described well by a flash-heating theory, above the sliding velocity of 1 cm/s regardless of pressure. At higher velocities, the velocity strengthening behavior replaced the velocity weakening behavior. This strengthening at higher velocities agrees with data from numerical simulations on sheared granular matter and is therefore described in terms of energy dissipation due to the inelastic deformation of grains. We propose a unified steady-state friction law that well describes the velocity and pressure dependence of the steady-state friction coefficient.

Kuwano, Osamu; Hatano, Takahiro

2011-09-01

95

Effect of cohesion on granular-fluid flows in spouted beds: PIV measurement and DEM simulations  

NASA Astrophysics Data System (ADS)

In contrast to wet granular flows, the effect of cohesion on complex granular-fluid flows is intriguing but much challenging. The liquid bridges, forming between binary particles with the addition of a small amount of liquids, might significantly change the granular-fluid system due to both cohesion and lubrication effects. In this paper, a spouted bed, among various fluidization technologies, is particularly selected as a prototypical system for studying granular-fluid flows, since it can provide a quasi-steady flow pattern of granular particles, i.e., a core of upward granular-fluid flow called the "spout" and a surrounding region of downward quasi-static granular flow called the "annulus". Firstly, using self-developed particle image velocimetery (PIV) technique, the effects of cohesion on the spout-annulus interface (namely the spout width) and on the particle velocity profiles in distinct zones are examined. Further, the discrete element method (DEM), by incorporating liquid bridge adhesion into soft-sphere model, is established and used to predict the microdynamic behavior of particles in spouted beds. Finally, based on both experiments and DEM validation, the effects on the granular patterns in these two zones are comparatively discussed.

Zhu, Runru; LI, Shuiqing; Yao, Qiang

2013-06-01

96

Granular mechanics and rifting  

NASA Astrophysics Data System (ADS)

Numerical models have proved useful in the interpretation of seismic-scale images of rifted margins. In an effort to both test and further illuminate predictions of numerical models, workers have made some strides using map-scale field relations, microstructures, and strain analyses. Yet, fundamental predictions of modeling and tectonic restorations are not able to capture critical observations. For example, many models and interpretations call on continuous faults with restorable kinematic histories. In contrast, s-reflectors and other interpreted shear fabrics in the middle crust tend to be discontinuous and non-planar across a margin. Additionally, most rift-evolution models and interpretations call on end-member ductile flow laws over a range of mechanical and thermal conditions. In contrast, field observations have found that a range of "brittle" fault rocks (e.g., cataclasites and breccias) form in the deeper crust. Similarly, upper crustal materials in deep basins and fault zones can deform through both distributed and localized deformation. Altogether, there appears to be reason to bring a new perspective to aspects of the structural evolution of rifted margins. A granular mechanics approach to crustal deformation studies has several important strengths. Granular materials efficiently localize shear and exhibit a range of stick-slip behaviors, including quasi-viscous rheological responses. These behaviors emerge in discrete element models, analog-materials experiments, and natural and engineered systems regardless of the specific micromechanical flow law. Yet, strictly speaking, granular deformation occurs via failure of frictional contacts between elastic grains. Here, we explore how to relate granular-mechanics models to mesoscale (outcrop) structural evolution, in turn providing insight into basin- and margin- scale evolution. At this stage we are focusing on analog-materials experiments and micro-to-mesoscale observations linking theoretical predictions to structural geological observations. With this combined approach we seek to establish characteristic length scales such as grain sizes and shear zone thicknesses, and time-scales such as stick-slip event dynamics. This would allow us to define a flow law at the mesoscale from comparing the experimental results and the field observations. This rheology could eventually be used to model the strain localization history of rifted margins

Reber, Jacqueline E.; Hayman, Nicholas W.; Lavier, Luc L.

2013-04-01

97

Ratcheting of granular materials.  

PubMed

We investigate the quasistatic mechanical response of soils under cyclic loading using a discrete model of randomly generated convex polygons. This response exhibits a sequence of regimes, each one characterized by a linear accumulation of plastic deformation with the number of cycles. At the grain level, a quasiperiodic ratchetlike behavior is observed at the contacts, which excludes the existence of an elastic regime. The study of this slow dynamics allows exploration of the role of friction in the permanent deformation of unbound granular materials subjected to cyclic loading. PMID:14995307

Alonso-Marroquín, F; Herrmann, H J

2004-02-06

98

Entangled Granular Media  

NASA Astrophysics Data System (ADS)

We study the geometrically induced cohesion of ensembles of granular “u particles” that mechanically entangle through particle interpenetration. We vary the length-to-width ratio l/w of the u particles and form them into freestanding vertical columns. In a laboratory experiment, we monitor the response of the columns to sinusoidal vibration (with peak acceleration ?). Column collapse occurs in a characteristic time ? which follows the relation ??exp(?/?). ? resembles an activation energy and is maximal at intermediate l/w. A simulation reveals that optimal strength results from competition between packing and entanglement.

Gravish, Nick; Franklin, Scott V.; Hu, David L.; Goldman, Daniel I.

2012-05-01

99

Entangled granular media.  

PubMed

We study the geometrically induced cohesion of ensembles of granular "u particles" that mechanically entangle through particle interpenetration. We vary the length-to-width ratio l/w of the u particles and form them into freestanding vertical columns. In a laboratory experiment, we monitor the response of the columns to sinusoidal vibration (with peak acceleration ?). Column collapse occurs in a characteristic time ? which follows the relation ??exp(?/?). ? resembles an activation energy and is maximal at intermediate l/w. A simulation reveals that optimal strength results from competition between packing and entanglement. PMID:23003190

Gravish, Nick; Franklin, Scott V; Hu, David L; Goldman, Daniel I

2012-05-17

100

What is soil organic matter worth?  

PubMed

The conservation and restoration of soil organic matter are often advocated because of the generally beneficial effects on soil attributes for plant growth and crop production. More recently, organic matter has become important as a terrestrial sink and store for C and N. We have attempted to derive a monetary value of soil organic matter for crop production and storage functions in three contrasting New Zealand soil orders (Gley, Melanic, and Granular Soils). Soil chemical and physical characteristics of real-life examples of three pairs of matched soils with low organic matter contents (after long-term continuous cropping for vegetables or maize) or high organic matter content (continuous pasture) were used as input data for a pasture (grass-clover) production model. The differences in pasture dry matter yields (non-irrigated) were calculated for three climate scenarios (wet, dry, and average years) and the yields converted to an equivalent weight and financial value of milk solids. We also estimated the hypothetical value of the C and N sequestered during the recovery phase of the low organic matter content soils assuming trading with C and N credits. For all three soil orders, and for the three climate scenarios, pasture dry matter yields were decreased in the soils with lower organic matter contents. The extra organic matter in the high C soils was estimated to be worth NZ$27 to NZ$150 ha(-1) yr(-1) in terms of increased milk solids production. The decreased yields from the previously cropped soils were predicted to persist for 36 to 125 yr, but with declining effect as organic matter gradually recovered, giving an accumulated loss in pastoral production worth around NZ$518 to NZ$1239 ha(-1). This was 42 to 73 times lower than the hypothetical value of the organic matter as a sequestering agent for C and N, which varied between NZ$22,963 to NZ$90,849 depending on the soil, region, discount rates, and values used for carbon and nitrogen credits. PMID:16510699

Sparling, G P; Wheeler, D; Vesely, E-T; Schipper, L A

2006-03-01

101

Size Segregation of Granular Materials  

Microsoft Academic Search

Segregation of granular materials due to size difference while flowing\\/energized is a very well known but poorly understood phenomena. Despite of some good understanding of the mechanism of size segregation, predictive models for size segregation are not available. Size segregation of binary granular mixtures flowing over inclined plane is studied by means of DEM simulations. Buoyant force acting on trace

Anurag Tripathi; D. V. Khakhar

2011-01-01

102

The Physics of Granular Media  

Microsoft Academic Search

This new reference provides quick access to the current level of knowledge, containing high-level review articles covering recent developments in the field of granular media from the viewpoints of applied, experimental, and theoretical physics. The authors represent different directions of research in the field, with their contributions covering: static properties of granular materials sand piles and avalanches vibration-induced patterns segregation

Haye Hinrichsen; Dietrich E. Wolf

2005-01-01

103

Sensory and Nutritional Evaluation of Meat Loaves With and Without Granular Soy Concentrate.  

National Technical Information Service (NTIS)

Meat loaves were prepared in accordance with Armed Forces Recipe L-35 using ground meat extended with hydrated granular soy concentrate (18% protein-wet basis). The hydrated soy protein was added to the ground meat at 10 and 20% levels. The primary object...

B. M. Atwood C. A. Kubik I. C. Fossum M. V. Klicka

1982-01-01

104

Dual Granular Temperature Oscillation of a Compartmentalized Bidisperse Granular Gas  

NASA Astrophysics Data System (ADS)

This paper investigates the evolution of granular temperatures for the oscillation of a bidisperse granular mixture in a vertically vibrated two-compartment container. The oscillation describes a periodic switch of light-particle cluster, followed by heavy-particle cluster, from one compartment to the other. We divide one half of a period of granular oscillation into L1-, L2-, and H-stages, depending on which type of particle is jumping over the barrier between the two compartments. The particle tracking velocimetry technique is used to measure particle velocities, from which the granular temperatures of each type of particles in each compartment are obtained. This study demonstrates that a temperature driven mechanism alone cannot explain the phenomenon of granular oscillation. In the H-stage (L2-stage), the difference in temperatures for heavy particles (light particles) between the two compartments is able to drive the particle flow; however, temperature mechanism is not valid in the L1-stage. The granular oscillation is then analyzed by a flux model, which confirms the temperature mechanism in the H- and L2-stages, and suggests that concentration difference could be an alternative factor to drive the light-particle flow in the L1-stage. In addition, a molecular dynamics simulation is also performed to study the evolution of granular oscillation.

Chen, Kuo-Ching; Lin, Chi-Hao; Li, Chia-Chieh; Li, Jian-Jhih

2009-04-01

105

Particle Deposition in Granular Media. Final report  

SciTech Connect

Objective is to understand aerosol deposition from gas streams flowing through granular media; this is important to the design of granular filtration systems. The following investigations were carried out: transient behavior of granular filtration of aerosols, and stochastic simulation of aerosol deposition in granular media.

Tien, C.

1992-12-31

106

Granular temperature profiles in three-dimensional vibrofluidized granular beds  

SciTech Connect

The motion of grains in a three-dimensional vibrofluidized granular bed has been measured using the technique of positron emission particle tracking, to provide three-dimensional packing fraction and granular temperature distributions. The mean square fluctuation velocity about the mean was calculated through analysis of the short time mean squared displacement behavior, allowing measurement of the granular temperature at packing fractions of up to {eta}{similar_to}0.15. The scaling relationship between the granular temperature, the number of layers of grains, and the base velocity was determined. Deviations between the observed scaling exponents and those predicted by recent theories are attributed to the influence of dissipative grain-sidewall collisions.

Wildman, R. D.; Huntley, J. M.; Parker, D. J.

2001-06-01

107

Wetting in electrolyte solutions  

NASA Astrophysics Data System (ADS)

Wetting of a charged substrate by an electrolyte solution is investigated by means of classical density functional theory applied to a lattice model. Within the present model the pure, i.e., salt-free solvent, for which all interactions are of the nearest-neighbor type only, exhibits a second-order wetting transition for all strengths of the substrate-particle and the particle-particle interactions for which the wetting transition temperature is nonzero. The influences of the substrate charge density and of the ionic strength on the wetting transition temperature and on the order of the wetting transition are studied. If the substrate is neutral, the addition of salt to the solvent changes neither the order nor the transition temperature of the wetting transition of the system. If the surface charge is nonzero, upon adding salt this continuous wetting transition changes to first-order within the wide range of substrate surface charge densities and ionic strengths studied here. As the substrate surface charge density is increased, at fixed ionic strength, the wetting transition temperature decreases and the prewetting line associated with the first-order wetting transition becomes longer. This decrease of the wetting transition temperature upon increasing the surface charge density becomes more pronounced by decreasing the ionic strength.

Ibagon, Ingrid; Bier, Markus; Dietrich, S.

2013-06-01

108

Pattern formation in granular and granular-fluid flows  

NASA Astrophysics Data System (ADS)

Particles and suspensions of particles in fluids are regularly used in many engineering disciplines such as catalysis and reaction engineering, environmental engineering, pharmaceutical engineering, etc. A few issues that are commonly encountered include ensuring homogeneity in pharmaceutical suspensions, predicting particle transport in atmospheric and effluent streams, and manufacturing uniform composite materials. Yet the fundamental study of particle motions in granular media or in highly concentrated granular suspensions has received little attention. Relevant issues of research interest include development of adaptive models that permit wide ranges of particle concentrations, improvement of analyses that allow physical interpretation of particle motions in any medium, of scales ranging from particle size to system size, and accurate validation of theoretical with experimental data. Given the above shortcomings, this dissertation will focus on investigating basic transport behavior of particles in fluids and developing predictive models for granular media and granular suspensions. Emphasis will be given to combining experiments with computations through examples of pattern forming phenomena in a granular medium and a dense granular-fluid system. The background motivation and the objectives of this dissertation are stated in the opening chapter 1. The next three chapters address these objectives in detail. First, chapter 2 presents experimental evidence, descriptions, and characteristics of novel patterns in a dense granular suspension. This is followed by chapter 3 in which a mean-field continuum model is derived to further elucidate the reported patterning phenomena. Chapter 4 uncovers several novel granular patterns experimentally and is concluded with a coarse-grained phenomenological model for granular surface flows. Lastly, chapter 5 closes the dissertation with conclusions and possible future directions. This work provides additional understanding and prediction of coexisting static (solid-like) and flowing (liquid-like) regions that are ubiquitous in granular flows. The mechanism of how the solid-like region differs from the fluid-like region will provide guidance for predicting related issues such as segregation and mixing of granular media, sedimentation and surface morphologies in multiphase flows and in nature.

Duong, Nhat-Hang P.

109

Dense Granular Flow around a Penetrating Object: Experiment and Hydrodynamic Model  

NASA Astrophysics Data System (ADS)

We present in this Letter experimental results on the bidimensional flow field around a cylinder penetrating into dense granular matter, together with drag force measurements. A hydrodynamic model based on extended kinetic theory for dense granular flow reproduces well the flow localization close to the cylinder and the corresponding scalings of the drag force, which is found to not depend on velocity, but linearly on the pressure and on the cylinder diameter and weakly on the grain size. Such a regime is found to be valid at a low enough “granular” Reynolds number.

Seguin, A.; Bertho, Y.; Gondret, P.; Crassous, J.

2011-07-01

110

Experimental velocity fields and forces for a cylinder penetrating into a granular medium  

NASA Astrophysics Data System (ADS)

We present here a detailed granular flow characterization together with force measurements for the quasi-bidimensional situation of a horizontal cylinder penetrating vertically at a constant velocity in dry granular matter between two parallel glass walls. In the velocity range studied here, the drag force on the cylinder does not depend on the velocity V0 and is mainly proportional to the cylinder diameter d. While the force on the cylinder increases with its penetration depth, the granular velocity profile around the cylinder is found to be stationary with fluctuations around a mean value leading to the granular temperature profile. Both mean velocity profile and temperature profile exhibit strong localization near the cylinder. The mean flow perturbation induced by the cylinder decreases exponentially away from the cylinder on a characteristic length ? that is mainly governed by the cylinder diameter for a large enough cylinder/grain size ratio d/dg: ?˜d/4+2dg. The granular temperature exhibits a constant plateau value T0 in a thin layer close to the cylinder of extension ?T0˜?/2 and decays exponentially far away with a characteristic length ?T of a few grain diameters (?T˜3dg). The granular temperature plateau T0 that scales as V02dg/d is created by the flow itself from the balance between the “granular heat” production by the shear rate V0/? over ?T0 close to the cylinder and the granular dissipation far away.

Seguin, A.; Bertho, Y.; Martinez, F.; Crassous, J.; Gondret, P.

2013-01-01

111

Exploring penetration through granular media  

NASA Astrophysics Data System (ADS)

The motion of objects through granular media is an important physical problem involving local jamming of the grains. We report on an experiment dealing with the force needed to initiate upward motion through a granular pile, Fini. As expected, this force scales monotonically with the depth of the intruder as well as its size, Dplate. However, unlike previous experiments this force also depends on the size of the particles making up the pile, dgrain. The force can be represented by the function Fini=A Dplate dgrain+B Dplate^2; which can be qualitatively explained within a simple model. Finally, preliminary results from a new experiment dealing with horizontal motion through a granular pile will be discussed. In this study, the effect of interstitial fluids on a granular material's resistance to an intruder will be investigated. Research supported by NASA grant NAG3-2384 and the NSF REU program.

Costantino, Daniel J.; Scheidemantel, Thomas J.; Stone, Matthew B.; Cole, Julia; Conger, Casey; Klein, Kit; Lohr, Matthew; McConville, William; Modig, Zachary; Scheidler, Krysten; Schiffer, Peter

2008-03-01

112

Couette flow of granular materials  

Microsoft Academic Search

The flow of granular materials between rotating cylinders is studied using a continuum model proposed by Rajagopal and Massoudi (A method for measuring material moduli for granular materials: flow in an orthogonal rheometer, DOE\\/PETC\\/TR90\\/3, 1990). For a steady, fully developed condition, the governing equations are reduced to a system of coupled non-linear ordinary differential equations. The resulting boundary value problem

J. Kumar; C. Lakshmana Rao; Mehrdad Massoudi

2003-01-01

113

Effects of cohesion on the flow patterns of granular materials in spouted beds.  

PubMed

Two-dimensional spouted bed, capable to provide both dilute granular gas and dense granular solid flow patterns in one system, was selected as a prototypical system for studying granular materials. Effects of liquid cohesion on such kind of complex granular patterns were studied using particle image velocimetry. It is seen that the addition of liquid oils by a small fraction of 10(-3)-10(-2) causes a remarkable narrowing (about 15%) of the spout area. In the dense annulus, as the liquid fraction increases, the downward particle velocity gradually decreases and approaches a minimum where, at a microscopic grain scale, the liquid bridge reaches spherical regimes with a maximum capillarity. Viscous lubrication effect is observed at a much higher fraction but is really weak with respect to the capillary effect. In the dilute spout, in contrast to the dry grains, the wet grains have a lightly smaller acceleration in the initial 1/3 of the spout, but have a dramatically higher acceleration in the rest of the spout. We attribute the former to the additional work needed to overcome interparticle cohesion during particle entrainment at the spout-annulus interface. Then, using mass and momentum balances, the latter is explained by the relative higher drag force resulting from both higher gas velocities and higher voidages due to spout narrowing in the wet system. The experimental findings will provide useful data for the validation of discrete element simulation of cohesive granular-fluid flows. PMID:23496504

Zhu, Runru; Li, Shuiqing; Yao, Qiang

2013-02-22

114

Effects of cohesion on the flow patterns of granular materials in spouted beds  

NASA Astrophysics Data System (ADS)

Two-dimensional spouted bed, capable to provide both dilute granular gas and dense granular solid flow patterns in one system, was selected as a prototypical system for studying granular materials. Effects of liquid cohesion on such kind of complex granular patterns were studied using particle image velocimetry. It is seen that the addition of liquid oils by a small fraction of 10-3-10-2 causes a remarkable narrowing (about 15%) of the spout area. In the dense annulus, as the liquid fraction increases, the downward particle velocity gradually decreases and approaches a minimum where, at a microscopic grain scale, the liquid bridge reaches spherical regimes with a maximum capillarity. Viscous lubrication effect is observed at a much higher fraction but is really weak with respect to the capillary effect. In the dilute spout, in contrast to the dry grains, the wet grains have a lightly smaller acceleration in the initial 1/3 of the spout, but have a dramatically higher acceleration in the rest of the spout. We attribute the former to the additional work needed to overcome interparticle cohesion during particle entrainment at the spout-annulus interface. Then, using mass and momentum balances, the latter is explained by the relative higher drag force resulting from both higher gas velocities and higher voidages due to spout narrowing in the wet system. The experimental findings will provide useful data for the validation of discrete element simulation of cohesive granular-fluid flows.

Zhu, Runru; Li, Shuiqing; Yao, Qiang

2013-02-01

115

[Effects of processing by granular heated beds on the chemical and functional properties of legume grains].  

PubMed

The present research compares the effect of cooking cowpea, canavalia and lupine by pressure cooking and by a granular bed roaster, on chemical and physical characteristics. The wet cooking process was carried out by pressure cooking at 121 degrees C for 30 min at 15 psi, using a bean-to-water ratio of 3 to 1. The cooked samples were dried with heated air (60 degrees C). The granular bed roasting was carried out at 200 and 250 degrees C for contact times of 2 and 2.5 minutes, at a 5 to 1 sand:bean ratio. For this process, a granular bed roaster was designed and constructed. This process induced in the grain temperatures which varied from 90-128 degrees C, and thermic efficiencies which fluctuated between 38 and 60%. The wet and the dry processes did not affect protein and fat content, although available lysine values decreased slightly. The two processes did not affect water absorption and water solubility. The nitrogen solubility index, however, decreased as roasting temperatures increased in the case of the granular bed roaster, and it also decreased in the wet-cooking procedure. Both processes affected color of the cooked flours, with a light orange color, suggesting non-enzymatic browning due to the high temperatures used. PMID:3151432

Loayza Jibaja, C; Bressani, R

1988-03-01

116

Adsorption and wetting  

Microsoft Academic Search

Adsorption and wetting are related phenomena. In order to improve knowledge of both and their relations, experiments, thermodynamics and a theoretical interpretation have been connected, starring n-alkanes.Starting from the Gibbs adsorption equation thermodynamic relations between vapour adsorption and wetting are derived. The surface pressure of a film, formed by vapour adsorption on a solid surface, is calculated by integrating the

L. J. M. Schlangen

1995-01-01

117

Electron transport properties of magnetic granular films  

NASA Astrophysics Data System (ADS)

In this paper, we present a review of electron transport properties of magnetic granular films. Magnetic granular films are nanocomposite materials which consist of magnetic nanoparticles embedded in a nonmagnetic matrix or assembling of magnetic nanoparticles. According to the style of the nonmagnetic matrix, microstructure and the electron transport mechanism of the films, the magnetic granular films were divided into three groups: (1) magnetic metal-metal granular films, (2) magnetic metal-insulator granular films and (3) magnetic nanocluster-assembled granular films. Moreover, we also systematically review the magnetic properties, transport properties and magnetoresistance effect of size-monodispersed Co and Fe nanocluster-assembled films.

Peng, DongLiang; Wang, JunBao; Wang, LaiSen; Liu, XiaoLong; Wang, ZhenWei; Chen, YuanZhi

2013-01-01

118

Solitary granular avalanches: stability, fingering and theoretical modeling  

NASA Astrophysics Data System (ADS)

Avalanching processes do not only occur in the air as we know of snow avalanches, mud flows and land-slides. Such events frequently happen below the see level as they take many forms from turbidity currents to thick sediment waves. In this study we report results on laboratory scale avalanche experiments taking place both in the air and under-water. In both cases a family of stable solitary erosion/deposition waves is observed [1]. At higher inclination angles, we show the existence of a long wavelength transverse instability followed by a coarsening and the onset of a fingering pattern. While the experiments strongly differ by the spatial and time scales, the agreement between the stability diagrams, the wavelengths selection and the avalanche morphology suggest a common erosion/deposition scenario. We also use these erosion/deposition waves to investigate the dynamics of granular flow and jamming in the frame work of the Partial Fluidization Theory (PFT) proposed by Aronson et al. to describe the dynamics of granular matter near jamming [2]. [1] F. Malloggi et al. Europhysics Letters, 2006, Erosion waves: Transverse instabilities and fingering 75, 825-831 [2] I. S. Aranson et al.. Transverse instability of avalanches in granular flows down an incline. Physical Review E, 2006, 73, 050302; I.S.Aronson et al., Non rheological properties of granular flows: exploring the near jamming limit, preprint (2007).

Malloggi, Florent; Andreotti, Bruno; Clément, Eric; Aronson, Igor; Tsimring, Lev

2008-03-01

119

Experimental investigation of plastic deformations before a granular avalanche.  

PubMed

We present an experimental study of the deformation inside a granular material that is progressively tilted. We investigate the deformation before the avalanche with a spatially resolved diffusive wave spectroscopy setup. At the beginning of the inclination process, we first observe localized and isolated events in the bulk, with a density which decreases with the depth. As the angle of inclination increases, series of microfailures occur periodically in the bulk, and finally a granular avalanche takes place. The microfailures are observed only when the tilt angles are larger than a threshold angle much smaller than the granular avalanche angle. We have characterized the density of reorganizations and the localization of microfailures. We have also explored the effect of the nature of the grains, the relative humidity conditions, and the packing fraction of the sample. We discuss those observations in the framework of the plasticity of granular matter. Microfailures may then be viewed as the result of the accumulation of numerous plastic events. PMID:23410323

Amon, Axelle; Bertoni, Roman; Crassous, Jérôme

2013-01-22

120

MICROWAVE SENSING OF MOISTURE IN GRANULAR MATERIALS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Principles for sensing moisture content of hygroscopic granular materials through their microwave dielectric properties will be explained. Applications of a new technique for determining the moisture content of granular materials from measurements of their dielectric properties, or permittivities, ...

121

Particle Deposition in Granular Media: Progress Report.  

National Technical Information Service (NTIS)

This paper discusses topics on particle deposition in granular media. The six topics discussed are: experimental determination of initial collection efficiency in granular beds - an assessment of the effect of instrument sensitivity and the extent of part...

C. Tien

1987-01-01

122

The Big Wet  

NSDL National Science Digital Library

This lesson plan is part of the DiscoverySchool.com lesson plan library for grades 6-8. It focuses on a particular climate found in Northern Australia, known as the tropical wet and dry. This lesson goes over the 12 categories of climates, and looks at the specifics of the 'big wet', or tropical wet and dry climate. It includes objectives, materials, procedures, discussion questions, evaluation ideas, performing extensions, suggested readings, and vocabulary. There are videos available to order which complement this lesson, audio vocabulary, and links to teaching tools for making custom quizzes, worksheets, puzzles and lesson plans.

123

Adsorption of Methyl Tertiary Butyl Ether on Granular Zeolites: Batch and Column Studies  

PubMed Central

Methyl tertiary butyl ether (MTBE) has been shown to be readily removed from water with powdered zeolites, but the passage of water through fixed beds of very small powdered zeolites produces high friction losses not encountered in flow through larger sized granular materials. In this study, equilibrium and kinetic adsorption of MTBE onto granular zeolites, a coconut shell granular activated carbon (CS-1240), and a commercial carbon adsorbent (CCA) sample was evaluated. In addition, the effect of natural organic matter (NOM) on MTBE adsorption was evaluated. Batch adsorption experiments determined that ZSM-5 was the most effective granular zeolite for MTBE adsorption. Further equilibrium and kinetic experiments verified that granular ZSM-5 is superior to CS-1240 and CCA in removing MTBE from water. No competitive-adsorption effects between NOM and MTBE were observed for adsorption to granular ZSM-5 or CS-1240, however there was competition between NOM and MTBE for adsorption onto the CCA granules. Fixed-bed adsorption experiments for longer run times were performed using granular ZSM-5. The bed depth service time model (BDST) was used to analyze the breakthrough data.

Abu-Lail, Laila; Bergendahl, John A.; Thompson, Robert W.

2010-01-01

124

Hydrodynamics of vibrated granular monolayer.  

SciTech Connect

We investigate the long-standing puzzle of phase separation in a granular monolayer vibrated from below. Although this system is three dimensional, an interesting dynamics occurs mostly in the horizontal plane, perpendicular to the direction of vibration. Experiments [Olafsen and Urbach, Phys. Rev. Lett. 81 4369 (1998)] demonstrated that for a high amplitude of vibration the system is in the gaslike phase, but when the amplitude becomes smaller than a certain threshold, a phase separation occurs: A solidlike dense condensate of particles forms in the center of the system, surrounded by particles in the gaslike phase. We explain theoretically the experimentally observed coexistence of dilute and dense phases, employing Navier-Stokes granular hydrodynamics. We show that the phase separation is associated with a negative compressibility of granular gas.

Khain, E.; Aranson, I. S. (Materials Science Division); (Oakland Univ.)

2011-01-01

125

Density waves in granular flow  

NASA Astrophysics Data System (ADS)

Ample experimental evidence has shown the existence of spontaneous density waves in granular material flowing through pipes or hoppers. Using Molecular Dynamics Simulations we show that several types of waves exist and find that these density fluctuations follow a 1/f spectrum. We compare this behaviour to deterministic one-dimensional traffic models. If positions and velocities are continuous variables the model shows self-organized criticality driven by the slowest car. We also present Lattice Gas and Boltzmann Lattice Models which reproduce the experimentally observed effects. Density waves are spontaneously generated when the viscosity has a nonlinear dependence on density which characterizes granular flow.

Herrmann, H. J.; Flekkøy, E.; Nagel, K.; Peng, G.; Ristow, G.

126

Unifying suspension and granular rheology.  

PubMed

Using an original pressure-imposed shear cell, we study the rheology of dense suspensions. We show that they exhibit a viscoplastic behavior similarly to granular media successfully described by a frictional rheology and fully characterized by the evolution of the friction coefficient ? and the volume fraction ? with a dimensionless viscous number I(v). Dense suspension and granular media are thus unified under a common framework. These results are shown to be compatible with classical empirical models of suspension rheology and provide a clear determination of constitutive laws close to the jamming transition. PMID:22107679

Boyer, François; Guazzelli, Élisabeth; Pouliquen, Olivier

2011-10-24

127

Distance Granularity Effect on MANET's Simulation  

Microsoft Academic Search

This paper describes the effect of distance granularity, used in the Ad-hoc wireless networks simulators (MANETs), on the simulation results and performance. Studying distance granularity effect is important as it plays a significant role in determining the level of details in the simulation results. The main goal of this research is to analyze the effect of using different distance granularities

Wesam Al Mobaideen; Emad Qaddoura; Ahmad Sharieh; Shatha Al Asir

2007-01-01

128

Jamming and Fluctuations in Granular Drag  

Microsoft Academic Search

We investigate the dynamic evolution of jamming in granular media through fluctuations in the granular drag force. The successive collapse and formation of jammed states give a stick-slip nature to the fluctuations which is independent of the contact surface between the grains and the dragged object, thus implying that the stress-induced collapse is nucleated in the bulk of the granular

I. Albert; P. Tegzes; B. Kahng; R. Albert; J. G. Sample; M. Pfeifer; A.-L. Barabási; T. Vicsek; P. Schiffer

2000-01-01

129

Wet Chemistry Instrument Prototype.  

National Technical Information Service (NTIS)

A wet chemistry instrument prototype for detecting amino acids in planetary soil samples was developed. The importance of amino acids and their condensation products to the development of life forms is explained. The characteristics of the instrument and ...

1974-01-01

130

Nonionic wetting agents  

Microsoft Academic Search

Purified polyglycol ester and ether types of non-ionic surfactants were investigated to determine optimum structures for wetting\\u000a hydrophobic soils, peat moss, and standard cotton skeins (Draves test). The most rapid wetting of hydrophobic soil was observed\\u000a with diethylene glycol monoesters of fatty acids possessing 8,9, and 10 carbon atoms and triethylene glycol monoesters of\\u000a fatty acids containing 9 and 10

J. K. Weil; R. E. Koos; W. M. Linfield; N. Parris

1979-01-01

131

Pattern formation in granular and granular-fluid flows  

Microsoft Academic Search

Particles and suspensions of particles in fluids are regularly used in many engineering disciplines such as catalysis and reaction engineering, environmental engineering, pharmaceutical engineering, etc. A few issues that are commonly encountered include ensuring homogeneity in pharmaceutical suspensions, predicting particle transport in atmospheric and effluent streams, and manufacturing uniform composite materials. Yet the fundamental study of particle motions in granular

Nhat-Hang P. Duong

2004-01-01

132

Stress fluctuations and macroscopic stick-slip in granular materials.  

PubMed

This paper deals with the quasi-static regime of deformation of granular matter. It investigates the size of the Representative Elementary Volume (REV), which is the minimum packing size above which the macroscopic mechanical behaviour of granular materials can be defined from averaging. The first part uses typical results from recent literature and finds that the minimum REV contains in general 10 grains; this result holds true either for most experiments or for Discrete Element Method (DEM) simulation. This appears to be quite small. However, the second part gives a counterexample, which has been found when investigating uniaxial compression of glass spheres which exhibit stick-slip; we show in this case that the minimum REV becomes 10(7) grains. This makes the system not computable by DEM. Moreover, similarity between the Richter law of seism and the exponential statistics of stick-slip is stressed. PMID:15010916

Evesque, P; Adjémian, F

2002-11-01

133

Mechanics of granular materials (MGM)  

Microsoft Academic Search

The constitutive behavior of uncemented granular materials such as strength, stiffness, and localization of deformations are to a large extent derived from interparticle friction transmitted between solid particles and particle groups. Interparticle forces are highly dependent on gravitational body forces. At very low effective confining pressures, the true nature of the Mohr envelope, which defines the Mohr-Coulomb failure criterion for

Khalid A. Alshibli; Nicholas C. Costes; Ronald F. Porter

1996-01-01

134

Granularity in software product lines  

Microsoft Academic Search

Building software product lines (SPLs) with features is a challeng- ing task. Many SPL implementations support features with coarse granularity - e.g., the ability to add and wrap entire methods. How- ever, fine-grained extensions, like adding a statement in the middle of a method, either require intricate workarounds or obfuscate the base code with annotations. Though many SPLs can and

Christian Kästner; Sven Apel; Martin Kuhlemann

2008-01-01

135

Physics in Action: Granular Materials  

NSDL National Science Digital Library

This article describes research on systems made up of small granular pieces, such as sand piles or containers of grain. In these "Collective" systems, the interactions of each of the grains with a few neighbors determines the properties of large systems.

Central, Physics

2004-04-02

136

Density waves in granular flow  

Microsoft Academic Search

Ample experimental evidence has shown the existence of spontaneous density waves in granular material flowing through pipes or hoppers. Using Molecular Dynamics Simulations we show that several types of waves exist and find that these density fluctuations follow a 1\\/f spectrum. We compare this behaviour to deterministic one-dimensional traffic models. If positions and velocities are continuous variables the model shows

H. J. Herrmann; E. Flekkøy; K. Nagel; G. Peng; G. Ristow

1994-01-01

137

Dynamics of Sheared Granular Materials  

Microsoft Academic Search

This work focuses on the properties of sheared granular materials near the jamming transition. The project currently involves two aspects. The first of these is an experiment that is a prototype for a planned ISS (International Space Station) flight. The second is discrete element simulations (DES) that can give insight into the behavior one might expect in a reduced-g environment.

Lou Kondic; Brian Utter; Robert P. Behringer

2002-01-01

138

Wetting Transition of Water  

NASA Astrophysics Data System (ADS)

Pure liquid water does not wet most solid surfaces. Liquid water on these surfaces beads up and forms droplets with a finite contact angle. General thermodynamic principles suggest that as the temperature approaches the critical point, the contact angle should go to zero, marking the wetting transition. We have made an optical cell which can operate near the critical point of water (Tc=373C, Pc=217 atm) to study this phenomenon on sapphire, graphite and silicon. We have used two methods to measure the wetting temperature of water on these surfaces. Firstly, we studied a single droplet on a horizontal surface and optically measured the change in contact angle as a function of increasing temperature. Second, we studied the condensation of droplets on a vertical plate as a function of temperature. As the temperature approached the wetting temperature in both cases, the droplets spread and eventually form a smooth film along the surface of the plate. The wetting temperature on sapphire is near 240C and is considerably higher on graphite. Our observed values of Tw are significantly higher than the predictions made by the sharp-kink approximation and recent molecular dynamics simulations.

Friedman, Serah; Khalil, Matt; Taborek, Peter

2013-03-01

139

Feasibility of Granular, Activated-Carbon Adsorption for Waste-Water Renovation.  

National Technical Information Service (NTIS)

Granular, activated carbon in packed-bed column contactors was shown to remove much of the organic matter including alkylbenesulfonate from municipal waste water. The COD of a secondary effluent was reduced to about 12 to 20 ppm and the ABS was removed al...

R. S. Joyce V. A. Sukenik

1964-01-01

140

Shear deformation in granular materials  

SciTech Connect

An investigation into the properties of granular materials is undertaken via numerical simulation. These simulations highlight that frictional contact, a defining characteristic of dry granular materials, and interfacial debonding, an expected deformation mode in plastic bonded explosives, must be properly modeled. Frictional contact and debonding algorithms have been implemented into FLIP, a particle in cell code, and are described. Frictionless and frictional contact are simulated, with attention paid to energy and momentum conservation. Debonding is simulated, with attention paid to the interfacial debonding speed. A first step toward calculations of shear deformation in plastic bonded explosives is made. Simulations are performed on the scale of the grains where experimental data is difficult to obtain. Two characteristics of deformation are found, namely the intermittent binding of grains when rotation and translation are insufficient to accommodate deformation, and the role of the binder as a lubricant in force chains.

Bardenhagen, S.G.; Brackbill, J.U. [Los Alamos National Lab., NM (United States); Sulsky, D.L. [Univ. of New Mexico, Albuquerque, NM (United States)

1998-12-31

141

Wetting transparency of graphene.  

PubMed

We report that graphene coatings do not significantly disrupt the intrinsic wetting behaviour of surfaces for which surface-water interactions are dominated by van der Waals forces. Our contact angle measurements indicate that a graphene monolayer is wetting-transparent to copper, gold or silicon, but not glass, for which the wettability is dominated by short-range chemical bonding. With increasing number of graphene layers, the contact angle of water on copper gradually transitions towards the bulk graphite value, which is reached for ~6 graphene layers. Molecular dynamics simulations and theoretical predictions confirm our measurements and indicate that graphene's wetting transparency is related to its extreme thinness. We also show a 30-40% increase in condensation heat transfer on copper, as a result of the ability of the graphene coating to suppress copper oxidation without disrupting the intrinsic wettability of the surface. Such an ability to independently tune the properties of surfaces without disrupting their wetting response could have important implications in the design of conducting, conformal and impermeable surface coatings. PMID:22266468

Rafiee, Javad; Mi, Xi; Gullapalli, Hemtej; Thomas, Abhay V; Yavari, Fazel; Shi, Yunfeng; Ajayan, Pulickel M; Koratkar, Nikhil A

2012-01-22

142

Wet and Wild Water.  

ERIC Educational Resources Information Center

|This guide uses a thematic approach to show the integration of subjects (reading, mathematics, language arts, science/fine arts) and skills to create a context for learning. The contents of this guide are presented in a holistic format. There are six major topics in the guide, each with subtopics: (1) "Getting Your Feet Wet--An Introduction to…

Indiana State Dept. of Education, Indianapolis. Center for School Improvement and Performance.

143

PREFACE: Wetting: introductory note  

Microsoft Academic Search

The discovery of wetting as a topic of physical science dates back two hundred years, to one of the many achievements of the eminent British scholar Thomas Young. He suggested a simple equation relating the contact angle between a liquid surface and a solid substrate to the interfacial tensions involved [1], gammalg cos theta = gammasg - gammasl (1) In

S. Herminghaus

2005-01-01

144

Wet-bulb thermometer  

US Patent & Trademark Office Database

A wet bulb thermometer. A temperature sensor which can function in a moist environment is placed in such a location that it will be within the mist of water produced by a nozzle when pressurized water is supplied to the nozzle. Preferably, the temperature sensor is placed somewhat below the nozzle to account for the effect of gravity upon the mist of water. Also, preferably, the temperature sensor produces an electrical signal that is indicative of temperature and that can be read by a computer. Accuracy of the determination of the wet-bulb temperature of the air is assured by the redundancy of this device. Evaporation from droplets in the mist assure that the temperature of the air within the mist is at the wet-bulb temperature as, independently, does the evaporation from the film of water which forms on the surface of the temperature sensor. Avoiding confining the spray and conducting liquid water from a reservoir to the temperature sensor eliminates potential external sources of heat which could prevent an accurate determination of the wet-bulb temperature.

1998-12-29

145

Bed-Wetting  

MedlinePLUS

... bed-wetting seem to be triggered by certain foods, drinks or activities? Is your child dry during the day? Is your child facing ... the body. Acupuncture may be effective for some children. Diet. Some people believe that certain foods affect bladder function and that removing these foods ...

146

Compaction properties of granular bentonites  

Microsoft Academic Search

Bentonites have been examined recently in some countries as candidates for buffer materials for use in high-level nuclear waste repositories. Granular bentonites are anticipated as the raw materials for constructing bentonite-based buffer materials by in-situ compaction methods. For that reason, it is important to understand the influence of grain size distribution and physicochemical properties of bentonite ore on compaction properties

Hiroshi Ito

2006-01-01

147

Rigidity of Dry Granular Solids  

NASA Astrophysics Data System (ADS)

Solids are distinguished from fluids by their ability to resist shear. In traditional solids, the resistance to shear come as an energy cost of straining, which works to distort density modulations that exists in both crystalline or amorphous structures. In our recent work,we focus on the emergence of shear-rigidity in a special class of solids: dry (non-cohesive) granular materials which have no energetically preferred density modulations. In contrast to traditional solids, the emergence of mechanical rigidity in these marginal granular solids is a collective process, which is controlled solely by boundary forces, the constraints of force and torque balance, and the positivity of the contact forces. We develop a theoretical framework based on these constraints, and show that these solids can be characterized by topological invariants and that, in two dimensions, they have internal patterns that are most naturally represented in the space of gauge field of the stress. Broken translational invariance in this gauge space is a necessary condition for rigidity in granular solids. We apply our theory to experimentally shear-jammed states as well as numerically generated jammed force networks to show that the statistics of stress fluctuations, and the ability of jammed configurations to resist deformations can be understood within this theoretical framework.

Bi, Dapeng

2013-03-01

148

Macro–micro relations in granular mechanics  

Microsoft Academic Search

In granular mechanics, macroscopic approaches treat a granular material as an equivalent continuum at macro-scale, and study its constitutive relationship between macro-quantities, such as stresses and strains. On the other hand, microscopic approaches consider a granular material as an assembly of individual particles interacting with each other at micro-scale (i.e., particle-scale), and the physical quantities under study are forces and

X. Li; H. S. Yu; X. S. Li

2009-01-01

149

FNA of thyroid granular cell tumor.  

PubMed

Granular cell tumor rarely occurs in the thyroid. This case report describes the cytologic features of a granular cell tumor seen in a fine needle aspirate obtained from a 27-year-old woman with a gradually enlarging thyroid nodule. The aspirate showed single as well as syncytial clusters of cells with abundant granular cytoplasm. The differential diagnosis in this case included granular cell tumor, Hurthle cell lesion/neoplasm, and a histiocytic reparative process. Immunohistochemical studies, including S-100 protein and CD68, performed on a cell block preparation were helpful in supporting the diagnosis. Diagn. Cytopathol. 2013;41:825-828. © 2012 Wiley Periodicals, Inc. PMID:22508678

Harp, Eric; Caraway, Nancy P

2012-04-17

150

75 FR 67105 - Granular Polytetrafluoroethylene Resin From Italy and Japan  

Federal Register 2010, 2011, 2012, 2013

...Granular Polytetrafluoroethylene Resin From Italy and Japan AGENCY: United States International...granular polytetrafluoroethylene resin from Italy and Japan...granular polytetrafluoroethylene resin from Italy and Japan would be likely to lead to...

2010-11-01

151

76 FR 4936 - Granular Polytetrafluoroethylene Resin From Italy  

Federal Register 2010, 2011, 2012, 2013

...Granular Polytetrafluoroethylene Resin From Italy AGENCY: United States International Trade...resin (``granular PTFE resin'') from Italy...duty orders on granular PTFE resin from Italy and Japan (75 FR 67082-67083 and...

2011-01-27

152

21 CFR 133.145 - Granular cheese for manufacturing.  

Code of Federal Regulations, 2010 CFR

... 2009-04-01 2009-04-01 false Granular cheese for manufacturing. 133.145 Section...Cheese and Related Products § 133.145 Granular cheese for manufacturing. Granular cheese for manufacturing conforms to the...

2009-04-01

153

21 CFR 133.145 - Granular cheese for manufacturing.  

Code of Federal Regulations, 2010 CFR

... 2010-04-01 2010-04-01 false Granular cheese for manufacturing. 133.145 Section...Cheese and Related Products § 133.145 Granular cheese for manufacturing. Granular cheese for manufacturing conforms to the...

2010-04-01

154

Underwater wet welding of steel  

Microsoft Academic Search

Underwater wet welding is conducted directly in water with the shielded metal arc (SMA) and flux cored arc (FCA) welding processes. Underwater wet welding has been demonstrated as an acceptable repair technique down to 100 meters (325 ft.) in depth, but wet welds have been attempted on carbon steel structures down to 200 meters (650 ft.). The primary purpose of

S. Ibarra; S. Liu; D. L. Olson

1995-01-01

155

The wetting of leaf surfaces  

Microsoft Academic Search

Recent advances in the area of the wetting of leaf areas are reviewed with particular emphasis on their relation to agrochemical application. Areas reviewed include leaf wax composition, leaf wetting and superhydrophobicity, agrochemical deposit formation and spray retention. It is thought that most progress has been made in the area of leaf wetting through the work on lotus leaves. In

Philip Taylor

2011-01-01

156

Wet air oxidation  

Microsoft Academic Search

Wet air oxidation (WAO), involving oxidation at high temperature (125--320 C) and pressure (0.5--20 MPa) conditions, is useful for the treatment of hazardous, toxic, and nonbiodegradable waste streams. The process becomes self-sustaining when the feed chemical oxygen demand (COD) is about 20,000 mg\\/l and can be a net energy producer at sufficient higher feed COD's. All the published information on

Vedprakash S. Mishra; Vijaykumar V. Mahajani; Jyeshtharaj B. Joshi

1995-01-01

157

Wetting of Porous Solids.  

PubMed

This paper presents a simple, three stage method to simulate the mechanics of wetting of porous solid objects, like sponges and cloth, when they interact with a fluid. In the first stage, we model the absorption of fluid by the object when it comes in contact with the fluid. In the second stage, we model the transport of absorbed fluid inside the object, due to diffusion, as a flow in a deforming, unstructured mesh. The fluid diffuses within the object depending on saturation of its various parts and other body forces. Finally, in the third stage, over-saturated parts of the object shed extra fluid by dripping. The simulation model is motivated by the physics of imbibition of fluids into porous solids in the presence of gravity. It is phenomenologically capable of simulating wicking and imbibition, dripping, surface flows over wet media, material weakening and volume expansion due to wetting. The model is inherently mass conserving and works for both thin 2D objects like cloth and for 3D volumetric objects like sponges. It is also designed to be computationally efficient and can be easily added to existing cloth, soft body and fluid simulation pipelines. PMID:23319518

Patkar, Saket; Chaudhuri, Parag

2013-01-10

158

Numerical studies of granular gases  

NASA Astrophysics Data System (ADS)

In this dissertation, we study velocity distributions in granular gases. For granular systems at low density, kinetic theory reduces to the Boltzmann equation which is based on the assumption of molecular chaos. At large velocity scales, stationary solutions with power-law tails, f( v) ˜ v--sigma, have been derived from the Boltzmann equation for spatially homogeneous granular systems [6]. The behavior of power-law tail is complete generic, holding for arbitrary dimension, arbitrary collision rules, and general collision rates. We find the non-Maxwellian steady states using event-driven molecular dynamics simulations. Firstly, power-law steady states are observed in driven systems where energy is injected rarely at large velocity scale V . The range of power-law tail shrinks when we increase the heating-dissipation ratio NINC , where NI and NC are number of injections and number of collisions, respectively. Then a crossover from a power-law to a stretched exponential distribution is developed when the heating-dissipation ratio NINC is close to 1. It is the energy cascade from a few energetic particles to the overwhelming majority of slowly moving particles that causes the non-Maxwellian velocity distributions. Steady states with power-law tail are robust as long as the injection velocity scale V is essentially separated from the typical velocity scale v0. These steady states are shown to exist for a wide range of number densities, different combinations of injection velocities and injection rates. The injection velocity scale V, the typical velocity scale v0, and the injection rate per particle are related by energy balance. This energy balance relation is confirmed by data collapse of velocity distributions for various choices of parameters.

Kang, Wenfeng

159

Theoretical model of granular compaction  

SciTech Connect

Experimental studies show that the density of a vibrated granular material evolves from a low density initial state into a higher density final steady state. The relaxation towards the final density follows an inverse logarithmic law. As the system approaches its final state, a growing number of beads have to be rearranged to enable a local density increase. A free volume argument shows that this number grows as N = {rho}/(1 {minus} {rho}). The time scale associated with such events increases exponentially e{sup {minus}N}, and as a result a logarithmically slow approach to the final state is found {rho} {infinity} {minus}{rho}(t) {approx_equal} 1/lnt.

Ben-Naim, E. [Los Alamos National Lab., NM (United States); Knight, J.B. [Princeton Univ., NJ (United States). Dept. of Physics; Nowak, E.R. [Univ. of Illinois, Urbana, IL (United States). Dept. of Physics]|[Univ. of Chicago, IL (United States). James Franck Inst.; Jaeger, H.M.; Nagel, S.R. [Univ. of Chicago, IL (United States). James Franck Inst.

1997-11-01

160

Thermoelectric performance of granular semiconductors.  

SciTech Connect

We study the effects of doping and confinement on the thermoelectric properties of nanocrystalline semiconductors. We calculate the thermopower and figure of merit for temperatures less than the charging energy. For weakly coupled semiconducting grains it is shown that the figure of merit is optimized for grain sizes of order 5 nm for typical materials, and that its value can be larger than one. Using the similarities between granular semiconductors and electron or Coulomb glasses allows for a quantitative description of inhomogeneous semiconducting thermoelectrics.

Glatz, A.; Beloborodov, I. S.; Materials Science Division; California State Univ.

2009-01-01

161

Rheology of confined granular flows  

SciTech Connect

The properties of confined granular flows on a heap are studied through numerical simulations and experiments. We address how such system can be simulated with period boundaries in the flow direction. The packing fraction and velocity profiles are found to be described by one length scale. The dependence of the kinematic properties on the number of grains and on micromechanical parameters (coefficient of restitution and coefficient of friction) is described. Our results show that the friction at the sidewalls gradually decreases and that this decrease can be explained by the intermittent motion of the grains in the quasistatic part of the flow.

Richard, Patrick; Valance, Alexandre; Metayer, Jean-Francois; Crassous, Jerome; Delannay, Renaud [Universite Rennes 1, Institut de Physique de Rennes, UMR CNRS 6251, 263 av. General Leclerc, 35042 Rennes cedex FRANCE (France); Louge, Michel [Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, NY 14853 (United States)

2010-05-05

162

Coarsening Transition for Shaken Granular Materials  

Microsoft Academic Search

We describe a coarsening transition which occurs for granular materials subject to vertical vibration, z = A \\\\cos (omega t). The traditional control parameter is Gamma = Aomega^2\\/g, where g is the acceleration of gravity. When a layer of granular material is shaken with Gamma > 1, a heap will form (for layer heights large compared to the particle size,

E. van Doorn; R. P. Behringer

1996-01-01

163

Principles, Applications, and Trends of Granular Computing  

Microsoft Academic Search

This paper is to introduce the principles, models and perspectives of granular computing, and discuss its applications in various domains such as data mining, software engineering, and human-computer interaction. The research and development trends in granular computing are predicted.

Jianchao Han; Nick Cercone

2010-01-01

164

Fatty Change of the Granular Pneumocyte  

Microsoft Academic Search

Fat vacuoles develop in the granular pneumocytes of guinea pigs exposed to severe hypoxia in low-pressure chambers. The osmiophilic lamellar bodies are apparently reduced in size and decreased in number. The fatty change of the granular pneumocyte may represent a metabolic alteration and interfere with the production of surfactant. This hypoxic lesion of the pneumocyte may be a significant factor

Enrique Valdivia; Jayashree Sonnad; James D'Amato

1966-01-01

165

TWO-STAGE GRANULAR ACTIVATED CARBON TREATMENT  

EPA Science Inventory

Two 6.3 l/sec (0.15 mgd), two-stage, packed-bed, downflow granular activated carbon pilot plants were operated continuously for 33 months using unfiltered and unchlorinated activated sludge plant effluent. The main objective of the study was to compare the performance of granular...

166

Simulating granular media on the computer  

Microsoft Academic Search

Granular materials, like sand or powder, can present very intriguing effects. When shaken, sheared or poured they show segregation, convection and spontaneous fluctuations in densities and stresses. I will discuss the modeling of a granular medium on a computer by simulating a packing of elastic spheres via Molecular Dynamics. Dissipation of energy and shear friction at collisions are included. In

H. J. Herrmann

1995-01-01

167

Simulating granular media on the computer  

Microsoft Academic Search

Granular materials, like sand or powder, can present very intriguing effects. When shaken, sheared or poured they show segregation, convection and spontaneous fluctuations in densities and stresses. I will discuss the modeling of a granular medium on a computer by simulating a packing of elastic spheres via Molecular Dynamics. Dissipation of energy and shear friction at collisions are included. In

H. J. Herrmann

168

Transition to movement in granular chute flows  

Microsoft Academic Search

This experimental investigation deals with the observation of the behaviour that dense granular materials present when they flow in steady regime on a rough chute, focusing the attention on the transition to movement of the bed and on quantities involved as the internal friction angle. An important aspect of the study is the identification of parameters that distinguish granular from

A. C. Santomaso; P. Canu

2001-01-01

169

Dynamic effective mass of granular media  

Microsoft Academic Search

We develop the concept of frequency dependent effective mass, M(omega), of jammed granular materials which occupy a rigid cavity to a filling fraction of 48%, the remaining volume being air of normal room condition or controlled humidity. The dominant features of M(omega) provide signatures of the dissipation of acoustic modes, elasticity and aging effects in the granular medium. We perform

Chaur-Jian Hsu; David L. Johnson; Rohit A. Ingale; John J. Valenza; Nicolas Gland; Hernan A. Makse

2006-01-01

170

Dynamic Effective Mass of Granular Media  

Microsoft Academic Search

We develop the concept of frequency dependent effective mass, Mtilde (omega), of jammed granular materials which occupy a rigid cavity to a filling fraction of 48%, the remaining volume being air of normal room condition or controlled humidity. The dominant features of Mtilde (omega) provide signatures of the dissipation of acoustic modes, elasticity, and aging effects in the granular medium.

Chaur-Jian Hsu; David L. Johnson; Rohit A. Ingale; John J. Valenza; Hernán A. Makse

2009-01-01

171

Experimental observation and an empirical model of enhanced heap stability resulting from the mixing of granular materials  

NASA Astrophysics Data System (ADS)

We report the existence of enhanced heap stability as a result of the mixing of granular materials. Our setup consists of a rectangular container, filled with a binary mixture of granular matter up to some height h, that is rapidly opened at one wall to allow repose angle (?c) formation. We develop an empirical model for ?c based on the Mohr-Coulomb failure criterion. The model is parameterized by an effective cohesion c and an effective coefficient of friction ? that depend on: (1) the granular proportions and (2) the c and ? for pure cases. Good agreement is achieved between the experiment and the model. We note that even the experimental fluctuations of ?c as a function of granular proportions are well correlated (<2% deviation) with the computed uncertainty of the empirical model.

Arciaga, M.; Pastor, M.; Batac, R.; Bantang, J.; Monterola, C.

2009-07-01

172

LLNL Granular Solids Flow Project  

NASA Astrophysics Data System (ADS)

This project is directed toward obtaining a fundamental understanding of the flow behavior of granular solids and multi-phase solids-containing systems. Here we report progress in two new areas of study, quasi-static deformations and suspension rheology. Discrete particle computer models have the potential for becoming very useful tools for understanding such problems. We have begun a reexamination of our computer models to see how they can most effectively be applied to the many granular solids flow problems that involve quasi-static deformations. We have carefully reviewed our models of tagential friction between elastic spheres in contact, and have developed improved algorithms. We have also initiated development of more complex models that include adhesive surface forces and non-constant coefficients of friction. These new algorithms will be added to the 3DSHEAR model in the near future. We are examining various approaches to determine the rheologic properties of suspensions. As part of this effort we are developing a general numerical method to calculate the hydrodynamic interactions for arbitrary assemblies of spheres in suspension. The first results with this method involve assemblies of a small number of equal size spheres with periodic boundaries.

Walton, O. R.

1988-01-01

173

Uncertainty quantification and granular thermodynamics  

NASA Astrophysics Data System (ADS)

To objectively assess a DEM model for granular flow, the DEM model must be able to randomly sample possible flow histories. Objective assessment is then based on comparing a sample of flows from the model with a sample of experimental flows by means of statistical inference. The practical implementation of this method of model assessment yields a model for the relationships among small collections of macroscopic flow variables. This model of relationships is analogous to models from classical thermodynamics, but is a fully stochastic summarization of bulk flow properties for a physical system that is not at equilibrium. It strongly distinguishes the microscale disorder within the flow from the between-experiment unpredictability of the bulk properties of the flow. It clearly identifies the sources of bulk property uncertainties, and allows ignorance of the detailed dynamics of the flow to be incorporated into the modelling process. This approach to constructing granular thermodynamic models will be compared with approaches to model development arising from modern statistical physics and with the development of the first thermodynamic models.

Picka, Jeffrey D.

2013-06-01

174

High Temperature Superconducting Granular Balls  

NASA Astrophysics Data System (ADS)

In nature, there are very few cases that granular particles could aggregate together by themselves to form a round ball. Application of electric field further destroys space's isotropy. Therefore, it is against common sense that an electric field could drive high Tc superconducting (HTSC) particles together to form a round ball. However, this is our finding. High Tc superconducting granular particles of ?m size in liquid nitrogen bind themselves together to form macroscopic balls under an electric field in milliseconds. Each ball holds over 10^6 particles and survives constant collisions with electrodes. We recently used liquid argon to raise the temperature from 77K through the Tc of BiSrCaCuO and confirmed that the balls disappeared once the particles were no longer in the superconductivity state. The boiling point of argon is 87.3K, just above the Tc of BiSrCaCuO. When the temperature was below T_c, a big ball was formed in liquid argon and bounced between the two electrodes. We then raised the temperature to pass T_c. The high speed camera caught the situation: the big ball was going to strike an electrode. However, in less than one millisecond, the ball disappeared at the collision: it broke into pieces (Fig.7b). This concludes that when temperature is above T_c, the force holding these particles together is disappeared. This clearly indicates that the ball formation is a result of superconductivity.

Tao, R.; Zhang, X.; Tang, X.

2000-03-01

175

Wetting in Color  

NASA Astrophysics Data System (ADS)

Colorimetric litmus tests such as pH paper have enjoyed wide commercial success due to their inexpensive production and exceptional ease of use. However, expansion of colorimetry to new sensing paradigms is challenging because macroscopic color changes are seldom coupled to arbitrary differences in the physical/chemical properties of a system. In this thesis I present in detail the development of Wetting in Color Technology, focusing primarily on its application as an inexpensive and highly selective colorimetric indicator for organic liquids. The technology exploits chemically-encoded inverse-opal photonic crystals to control the infiltration of fluids to liquid-specific spatial patterns, projecting minute differences in liquids' wettability to macroscopically distinct, easy-to-visualize structural color patterns. It is shown experimentally and corroborated with theoretical modeling using percolation theory that the high selectivity of wetting, upon-which the sensitivity of the indicator relies, is caused by the highly symmetric structure of our large-area, defect-free SiO2 inverse-opals. The regular structure also produces a bright iridescent color, which disappears when infiltrated with liquid - naturally coupling the optical and fluidic responses. Surface modification protocols are developed, requiring only silanization and selective oxidation, to facilitate the deterministic design of an indicator that differentiates a broad range of liquids. The resulting tunable, built-in horizontal and vertical chemistry gradients allow the wettability threshold to be tailored to specific liquids across a continuous range, and make the readout rely only on countable color differences. As wetting is a generic fluidic phenomenon, Wetting in Color technology could be suitable for applications in authentication or identification of unknown liquids across a broad range of industries. However, the generic nature of the response also ensures chemical non-specificity. It is shown that combinatorial measurements from an array of indicators add a degree of chemical specificity to the platform, which can be further improved by monitoring the drying of the inverse-opal films. While colorimetry is the central focus of this thesis, applications of this platform in encryption, fluidics and nanofabrication are also briefly explored.

Burgess, Ian Bruce

176

Optical wet steam monitor  

DOEpatents

A wet steam monitor determines steam particle size by using laser doppler velocimeter (LDV) device to produce backscatter light. The backscatter light signal is processed with a spectrum analyzer to produce a visibility waveform in the frequency domain. The visibility waveform includes a primary peak and a plurality of sidebands. The bandwidth of at least the primary frequency peak is correlated to particle size by either visually comparing the bandwidth to those of known particle sizes, or by digitizing the waveform and comparing the waveforms electronically. 4 figures.

Maxey, L.C.; Simpson, M.L.

1995-01-17

177

Wet coastal plain tundra  

SciTech Connect

This years's census data for the wet coastal plain tundra in Alaska; North Slope Borough, 3 km SSW of Naval Arctic Research Laboratory, Barrow; 71/sup 0/ 18'N, 156/sup 0/ 43'W; Barrow Quadrangle, USGS, reflect an increase in breeding species of 31% over the 5-year average, while breeding density was up 22%. Ten species increased and only 4 decreased. There was a total of 17 species; 61.5 territorial males or females (171/km/sup 2/, 69/100 acres).

Myers, J.P.; McCaffery, B.J.; Pitelka, F.A.

1980-01-01

178

BOOK REVIEW: Kinetic Theory of Granular Gases  

NASA Astrophysics Data System (ADS)

Granular gases are composed of macroscopic bodies kept in motion by an external energy source such as a violent shaking. The behaviour of such systems is quantitatively different from that of ordinary molecular gases: due to the size of the constituents, external fields have a stronger effect on the dynamics and, more importantly, the kinetic energy of the gas is no longer a conserved quantity. The key role of the inelasticity of collisions has been correctly appreciated for about fifteen years, and the ensuing consequences in terms of phase behaviour or transport properties studied in an increasing and now vast body of literature. The purpose of this book is to help the newcomer to the field in acquiring the essential theoretical tools together with some numerical techniques. As emphasized by the authors—who were among the pioneers in the domain— the content could be covered in a one semester course for advanced undergraduates, or it could be incorporated in a more general course dealing with the statistical mechanics of dissipative systems. The book is self-contained, clear, and avoids mathematical complications. In order to elucidate the main physical ideas, heuristic points of views are sometimes preferred to a more rigorous route that would lead to a longer discussion. The 28 chapters are short; they offer exercises and worked examples, solved at the end of the book. Each part is supplemented with a relevant foreword and a useful summary including take-home messages. The editorial work is of good quality, with very few typographical errors. In spite of the title, kinetic theory stricto sensu is not the crux of the matter covered. The authors discuss the consequences of the molecular chaos assumption both at the individual particle level and in terms of collective behaviour. The first part of the book addresses the mechanics of grain collisions. It is emphasized that considering the coefficient of restitution ? —a central quantity governing the inelasticity of inter-grain encounters—as velocity independent is inconsistent with the mechanical point of view. An asymptotic expression for the impact velocity dependence of ? is therefore derived for visco-elastic spheres. The important inelastic Boltzmann equation is introduced in part II and the associated velocity distribution characterized for a force-free medium (so-called free cooling regime). Transport processes can then be analyzed in part III at the single particle level, and part IV from a more macroscopic viewpoint. The corresponding Chapman Enskog-like hydrodynamic approach is worked out in detail, in a clear fashion. Finally, the tendency of granular gases to develop instabilities is illustrated in part V where the hydrodynamic picture plays a pivotal role. This book clearly sets the stage. For the sake of simplicity, the authors have discarded some subtle points, such as the open questions underlying the hydrodynamic description (why include the temperature among the hydrodynamic modes, and what about the separation of space and time scales between kinetic and hydrodynamic excitations?). Such omissions are understandable. To a certain extent however, the scope of the book is centered on previous work by the authors, and I have a few regrets. Special emphasis is put on the (variable ?) visco-elastic model, which enhances the technical difficulty of the presentation. On the other hand, the important physical effects including scaling laws, hydrodynamic behaviour and structure formation, can be understood in two steps, from the results derived within the much simpler constant ? model, allowing subsequently \\varepsilon to depend on the granular temperature. The authors justify their choice with the inconsistency of the constant ? route. The improvements brought by the visco-elastic model remain to be assessed, since the rotational degrees of freedom, discarded in the book, play an important role and require due consideration of both tangential and normal restitution coefficients, that are again velocity dependent. This seems to be the price of a cons

Trizac, Emmanuel

2005-11-01

179

Experimental Investigation of the Wet Oxidation Destruction of Shipboard Waste Streams.  

National Technical Information Service (NTIS)

Increasingly stringent water qualtiy regulations anticipate the need for treating all shipboard waste streams containing combustible matter. Wet air oxidation or pressurized aqueous combustion conducted at 475 to 600F at operating pressures from 600 to 18...

P. Schatzberg D. F. Jackson C. M. Kelly

1974-01-01

180

Spatio-structural granularity of biological material entities  

Microsoft Academic Search

BACKGROUND: With the continuously increasing demands on knowledge- and data-management that databases have to meet, ontologies and the theories of granularity they use become more and more important. Unfortunately, currently used theories and schemes of granularity unnecessarily limit the performance of ontologies due to two shortcomings: (i) they do not allow the integration of multiple granularity perspectives into one granularity

Lars Vogt

2010-01-01

181

Establishing predictive capabilities of DEM - Verification and validation for complex granular processes  

NASA Astrophysics Data System (ADS)

The discrete element method has been increasingly used to model granular processes of increasing complexity, from dry to wet to multiphase systems. Whilst DEM has been shown to produce qualitatively many of the complex phenomena observed in these complex granular systems, establishing the extent of the predictive capability of DEM model is still in its infancy. This summary paper discusses the need to develop verification and validation methodologies with regard to DEM computations. It proposes the need to first verify that a DEM code with its implemented mathematical model and computation algorithm is accurately reproducing the conceptual model and its solution, before validating to determine the degree to which the computational model accurately represent the physics being modelled. It also discusses the associated issue of data analysis to extract the parameters of interest from DEM particle scale data.

Ooi, Jin Y.

2013-06-01

182

Wet ZZW construction for steganography  

Microsoft Academic Search

Wet paper codes are an essential tool for communication with non-shared selection channels. Inspired by the recent ZZW construction for matrix embedding, we propose a novel wet paper coding scheme with high embedding efficiency. The performance is analyzed under the assumption that wet cover elements form an i.i.d. Bernoulli sequence. Attention is paid to implementation details to minimize capacity loss

Tomáö Filler; Jessica Fridrich

2009-01-01

183

Wetting of Nanopatterned Grooved Surfaces  

SciTech Connect

The wetting by perfluoromethylcyclohexane of a well-defined silicon grating with a channel width of 16 nm has been studied using transmission small angle x-ray scattering. Prefilling, capillary filling, and postfilling wetting regimes have been identified. A detailed comparison of the data with theory reveals the importance of long-ranged substrate-fluid and fluid-fluid interactions for determining the wetting behavior on these length scales, especially at the onset of capillary condensation and in the prefilling regime.

T Hofmann; M Tasinkevych; A Checco; L Dobisz; S Dietrich; B Ocko

2011-12-31

184

Granular metamaterials for vibration mitigation  

NASA Astrophysics Data System (ADS)

Acoustic metamaterials that allow low-frequency band gaps are interesting for many practical engineering applications, where vibration control and sound insulation are necessary. In most prior studies, the mechanical response of these structures has been described using linear continuum approximations. In this work, we experimentally and theoretically address the formation of low-frequency band gaps in locally resonant granular crystals, where the dynamics of the system is governed by discrete equations. We investigate the quasi-linear behavior of such structures. The analysis shows that a stopband can be introduced at about one octave lower frequency than in materials without local resonances. Broadband and multi-frequency stopband characteristics can also be achieved by strategically tailoring the non-uniform local resonance parameters.

Gantzounis, G.; Serra-Garcia, M.; Homma, K.; Mendoza, J. M.; Daraio, C.

2013-09-01

185

Hysteresis in vibrated granular media  

NASA Astrophysics Data System (ADS)

Some general dynamical properties of models for compaction of granular media based on master equations are analyzed. In particular, a one-dimensional lattice model with short-ranged dynamical constraints is considered. The stationary state is consistent with Edward's theory of powders. The system is submitted to processes in which the tapping strength is monotonically increased and decreased. In such processes the behavior of the model resembles the reversible-irreversible branches which have been recently obaserved in experiments. This behavior is understood in terms of the general dynamical properties of the model, and related to the hysteresis cycles exhibited by structural glasses in thermal cycles. The existence of a "normal" solution, i.e., a solution of the master equation which is monotonically approached by all the other solutions, plays a fundamental role in the understanding of the hysteresis effects.

Prados, A.; Brey, J. J.; Sanchez-Rey, B.

2000-09-01

186

Capillary Fracturing in Granular Media  

NASA Astrophysics Data System (ADS)

We study the displacement of immiscible fluids in deformable, noncohesive granular media. Experimentally, we inject air into a thin bed of water-saturated glass beads and observe the invasion morphology. The control parameters are the injection rate, the bead size, and the confining stress. We identify three invasion regimes: capillary fingering, viscous fingering, and “capillary fracturing,” where capillary forces overcome frictional resistance and induce the opening of conduits. We derive two dimensionless numbers that govern the transition among the different regimes: a modified capillary number and a fracturing number. The experiments and analysis predict the emergence of fracturing in fine-grained media under low confining stress, a phenomenon that likely plays a fundamental role in many natural processes such as primary oil migration, methane venting from lake sediments, and the formation of desiccation cracks.

Holtzman, Ran; Szulczewski, Michael L.; Juanes, Ruben

2012-06-01

187

Capillary fracturing in granular media.  

PubMed

We study the displacement of immiscible fluids in deformable, noncohesive granular media. Experimentally, we inject air into a thin bed of water-saturated glass beads and observe the invasion morphology. The control parameters are the injection rate, the bead size, and the confining stress. We identify three invasion regimes: capillary fingering, viscous fingering, and "capillary fracturing," where capillary forces overcome frictional resistance and induce the opening of conduits. We derive two dimensionless numbers that govern the transition among the different regimes: a modified capillary number and a fracturing number. The experiments and analysis predict the emergence of fracturing in fine-grained media under low confining stress, a phenomenon that likely plays a fundamental role in many natural processes such as primary oil migration, methane venting from lake sediments, and the formation of desiccation cracks. PMID:23004989

Holtzman, Ran; Szulczewski, Michael L; Juanes, Ruben

2012-06-28

188

Rheology of surface granular flows  

NASA Astrophysics Data System (ADS)

Surface granular flow, comprising granular material flowing on the surface of a heap of the same material, occurs in several industrial and natural systems. The rheology of such a flow was investigated by means of measurements of velocity and number-density profiles in a quasi-two-dimensional rotating cylinder, half-filled with a model granular material monosize spherical stainless-steel particles. The measurements were made at the centre of the cylinder, where the flow is fully developed, using streakline photography and image analysis. The stress profile was computed from the number-density profile using a force balance which takes into account wall friction. Mean-velocity and root-mean-square (r.m.s.)-velocity profiles are reported for different particle sizes and cylinder rotation speeds. The profiles for the mean velocity superimpose when distance is scaled by the particle diameter d and velocity by a characteristic shear rate dot{gamma}_C = [gsin(beta_m-beta_s)/dcosbeta_s](1/2) and the particle diameter, where beta_m is the maximum dynamic angle of repose and beta_s is the static angle of repose. The maximum dynamic angle of repose is found to vary with the local flow rate. The scaling is also found to work for the r.m.s. velocity profiles. The mean velocity is found to decay exponentially with depth in the bed, with decay length lambda=1.1d. The r.m.s. velocity shows similar behaviour but with lambda=1.7d. The r.m.s. velocity profile shows two regimes: near the free surface the r.m.s. velocity is nearly constant and below a transition point it decays linearly with depth. The shear rate, obtained by numerical differentiation of the velocity profile, is not constant anywhere in the layer and has a maximum which occurs at the same depth as the transition in the r.m.s. velocity profile. Above the transition point the velocity distributions are Gaussian and below the transition point the velocity distributions gradually approach a Poisson distribution. The shear stress increases roughly linearly with depth. The variation in the apparent viscosity eta with r.m.s. velocity u shows a relatively sharp transition at the shear-rate maximum, and in the region below this point the apparent viscosity eta˜ u(-1.5) . The measurements indicate that the flow comprises two layers: an upper low-viscosity layer with a nearly constant r.m.s. velocity and a lower layer of increasing viscosity with a decreasing r.m.s. velocity. The thickness of the upper layer depends on the local flow rate and is independent of particle diameter while the reverse is found to hold for the lower-layer thickness. The experimental data is compared with the predictions of three models for granular flow.

Orpe, Ashish V.; Khakhar, D. V.

189

Local elastic fields in granular solids  

NASA Astrophysics Data System (ADS)

The modeling of the elastic properties of disordered or granular solids requires a theory of elasticity that takes non-affine deformations into account. Using a linearized force law, the non-affine elastic deformations are calculated. Based on the microscopically exact expressions for the local strain and stress fields, a way to calculate maps of the local linear elastic constants for fictional granular packings is presented. The elastic constants are found to be scale and system size independent withing an appropriate parameter range. Deviations from classical elasticity due to the micropolar nature of granular materials is studied.

Boberski, J.; Brendel, L.; Wolf, D. E.

2013-06-01

190

Stress- and rate-controlled granular rheology  

NASA Astrophysics Data System (ADS)

Granular solid hydrodynamics (GSH) is employed to account for granular rheology, both the rate-controlled one, smoothly extending from the critical state to the Bagnold regime, and the stress-controlled one that is discontinuous and hysteretic. Employing GSH, it is shown that a quiescent state is stable below the smaller jamming stress and instable above the larger fluidization stress, with values in between being metastable; also, that the MiDi relation, appropriate for rigid grains, needs to be rectified, because real granular media, with a sound velocity one to three times that of air, are soft.

Jiang, Yimin; Liu, Mario

2013-06-01

191

The data reduction based on granular computing  

NASA Astrophysics Data System (ADS)

This paper first defines the elementary granulation and the granulation, and other concepts, then we could convert decision tables to granular graph, and make visual presentation of them .some relevant knowledge of graph theory is applied to granular graph and its computing. In the paper it is shown that it is feasible and effective that granular graph is applied in describing data reduction. The method has the characteristic of simple and visual form and so on. Compared with other analysis methods, its time complexity is decreased to O(n).

Deng, Shaobo; Guan, Sujie

2011-12-01

192

Jamming and fluctuations in granular drag  

PubMed

We investigate the dynamic evolution of jamming in granular media through fluctuations in the granular drag force. The successive collapse and formation of jammed states give a stick-slip nature to the fluctuations which is independent of the contact surface between the grains and the dragged object, thus implying that the stress-induced collapse is nucleated in the bulk of the granular sample. We also find that while the fluctuations are periodic at small depths, they become "stepped" at large depths, a transition which we interpret as a consequence of the long-range nature of the force chains. PMID:10990882

Albert; Tegzes; Kahng; Albert; Sample; Pfeifer; Barabasi; Vicsek; Schiffer

2000-05-29

193

Collisional granular flow as a micropolar fluid.  

PubMed

We show that a micropolar fluid model successfully describes collisional granular flows on a slope. A micropolar fluid is the fluid with internal structures in which coupling between the spin of each particle and the macroscopic velocity field is taken into account. It is a hydrodynamical framework suitable for granular systems which consists of particles with macroscopic size. We demonstrate that the model equations can quantitatively reproduce the velocity and the angular velocity profiles obtained from the numerical simulation of the collisional granular flow on a slope using a simple estimate for the parameters in the theory. PMID:12005760

Mitarai, Namiko; Hayakawa, Hisao; Nakanishi, Hiizu

2002-04-12

194

Structural features in granular flows  

SciTech Connect

High-speed motion pictures document a series of essentially two-dimensional, free-surface flows of 6-mm diameter plastic spheres generated in an inclined glass-walled chute 3.7 m long and 6.7 mm wide. Flows at sufficiently low inclination or high particle flux can generally be divided into frictional and collisional regions. The frictional region typically consists of a quasi-static zone extending up from the fixed bed and an overlying block-gliding zone, in which coherent blocks of grains move parallel to the bed. The collisional region overlies the contact region in sufficiently deep flows; otherwise it extends to the bed. It typically consists of three zones: a lower grain-layer-gliding zone, in which grains appear to slide over one another; a middle chaotic zone, in which grain motions are highly random, as in a dense gas; and an overlying saltational zone, in which grains trace long, curved paths. In none of the flows does a frictional region overlie a collisional region. Zone thicknesses and block dimensions are previously unrecognized length scales in granular flows. The no-slip velocity boundary condition applies only when a frictional region adjoins a geometrically rough fixed bed, otherwise significant slip occurs (up to 50% of the mean flow velocity). Because many collision-dominated geophysical flows start from friction-dominated ones and end by reverting to the frictional regime as the energy supply diminishes, kinetic theories of granular flow, which unanimously employ the binary-collision assumption, can at best describe only a portion of the phenomena. Microstructural descriptions of the relatively slow, compact, and frictional regions evident in most geophysical flows are required to complement existing kinetic theories.

Drake, T.G. (Univ. of California, Los Angeles (United States))

1990-06-10

195

Ion metal synthesis in viscous organic matter  

Microsoft Academic Search

The viscosity of the irradiated target as new parameter was introduced in ion implantation physics of organic matter. It was experimentally shown that using this parameter one enables to monitor the process of ion synthesis of thin granular impurity films. As an example, the results of high-dose implantation of Co+ and Ag+ ions in viscous epoxy experimenting stages of cure

I. B. Khaibullin; R. I. Khaibullin; S. N. Abdullin; A. L. Stepanov; Yu. N. Osin; V. V. Bazarov; S. P. Kurzin

1997-01-01

196

Wetting transitions of Ne  

NASA Astrophysics Data System (ADS)

We report studies of the wetting behavior of Ne on very weakly attractive surfaces, carried out with the grand canonical Monte Carlo method. The Ne-Ne interaction was taken to be of Lennard-Jones form, while the Ne-surface interaction was derived from an ab initio calculation of Chizmeshya et al. [J. Low Temp. Phys. 110, 677 (1998)]. Nonwetting behavior was found for Li, Rb, and Cs in the temperature regime explored (i.e., T<42 K). Drying behavior was manifested in a depleted fluid density near the Cs surface. In contrast, for the case of Mg (a more attractive potential) a prewetting transition was found near T=28 K. This temperature was found to shift slightly when a corrugated potential was used instead of a uniform potential. The isotherm shape and the density profiles did not differ qualitatively between these cases.

Bojan, M. J.; Stan, G.; Curtarolo, S.; Steele, W. A.; Cole, M. W.

1999-01-01

197

Wetting front instability in an initially wet unsaturated fracture  

SciTech Connect

Experimental results exploring gravity-driven wetting front instability in a pre-wetted, rough-walled analog fracture are presented. Initial conditions considered include a uniform moisture field wetted to field capacity of the analog fracture and the structured moisture field created by unstable infiltration into an initially dry fracture. As in previous studies performed under dry initial conditions, instability was found to result both at the cessation of stable infiltration and at flux lower than the fracture capacity under gravitational driving force. Individual fingers were faster, narrower, longer, and more numerous than observed under dry initial conditions. Wetting fronts were found to follow existing wetted structure, providing a mechanism for rapid recharge and transport.

Nicholl, M.J.; Glass, R.J.; Nguyen, H.A.

1992-12-31

198

Scale-up of catalytic wet oxidation under moderate conditions  

SciTech Connect

The Catalytic Wet Oxidation with pure oxygen is a suitable treatment process for the degradation of organic matter in wastewaters and sludges. The applied moderate reaction conditions lead only to a partial oxidation of the organics. Therefore the resulting process water has to be purified in a biological treatment plant. In this study, experimental data collected during the wet oxidation of phenol and sewage sludge in a laboratory batch reactor as well as in a pilot plant are presented. A generalized kinetic model combined with a residence time analysis allows to predict accurately the degradation of organic matter in the pilot plant. The wet oxidation of wastewaters and sewage sludge was realized in one single plant concept. Treating suspended or diluted organic wastes produces a highly biodegradable process water containing low molecular oxidation products. The investigated Catalytic Wet Oxidation of sewage sludge generates a residual solid complying with the European quality standards of disposal concerning leachability and organic content. Due to its low capital and operating costs, the Catalytic Wet Oxidation process constitutes an acceptable alternative to incineration for the disposal of sludges.

Harf, J.; Hug, A.; Vogel, F.; Rohr, P.R. von [Swiss Federal Inst. of Tech., Zuerich (Switzerland). Inst. of Process Engineering

1999-05-01

199

Non-Local Theory of Granular Media.  

National Technical Information Service (NTIS)

A comprehensive theoretical derivation for the equations of motion of granular media in three dimensions. The derivation is based on both the probabilistic theory of motion of discreet particles, and utilizes the concepts of non-local thermodynamics.

K. C. Valanis

1992-01-01

200

Temperature Properties in Polydisperse Granular Mixtures  

NASA Astrophysics Data System (ADS)

Numerical simulations are employed to consider the problem of determining the granular temperatures of the species of a homogeneous heated granular mixture with a power-law size distribution. The partial granular temperature ratios are studied as functions of the fractal dimension D, the restitution coefficient e, the rescaled viscosity time, the average occupied area fraction varphi, the total particle number N and the number fraction. Different species of particles in a power-law system typically do not have the same mean kinetic energy, namely the granular temperature. It is found that the extent of nonequipartition of kinetic energy is determined by the fractal dimension D, the restitution coefficient e and the rescaled viscosity time, while is insensitive to the total particle number N, the area fraction varphi and the number fraction.

Li, Rui; Xiao, Ming; Li, Zhi-Hao; Zhang, Duan-Ming

2013-02-01

201

Clustering and phases of compartmentalized granular gases  

NASA Astrophysics Data System (ADS)

This paper experimentally investigates the clustering conditions for compartmentalized monodisperse granular gases, determining the critical particle number and condensation granular temperature at the gas-clustering transition. When one heavier intruding particle is added to a monodisperse gas, it is found that the condensation temperature decreases with the ratio of the mass of the intruding particle to that of the background particle. This phenomenon can be mathematically characterized by a proposed linear relation, which is reminiscent of a relation between the freezing point depression for a solvent and the concentration of an added solute. Finally we perform various tests by changing the numbers of two types of particles in bidisperse granular mixtures to construct the phase diagrams, which present the range of the five different states, namely, homogeneous gas, unstable-gas, one-clustering, two-clustering, and granular oscillation states.

Chen, K. C.; Li, C. C.; Lin, C. H.; Guo, G. H.

2009-02-01

202

Clustering and phases of compartmentalized granular gases.  

PubMed

This paper experimentally investigates the clustering conditions for compartmentalized monodisperse granular gases, determining the critical particle number and condensation granular temperature at the gas-clustering transition. When one heavier intruding particle is added to a monodisperse gas, it is found that the condensation temperature decreases with the ratio of the mass of the intruding particle to that of the background particle. This phenomenon can be mathematically characterized by a proposed linear relation, which is reminiscent of a relation between the freezing point depression for a solvent and the concentration of an added solute. Finally we perform various tests by changing the numbers of two types of particles in bidisperse granular mixtures to construct the phase diagrams, which present the range of the five different states, namely, homogeneous gas, unstable-gas, one-clustering, two-clustering, and granular oscillation states. PMID:19391739

Chen, K C; Li, C C; Lin, C H; Guo, G H

2009-02-27

203

Acoustical properties of double porosity granular materials.  

PubMed

Granular materials have been conventionally used for acoustic treatment due to their sound absorptive and sound insulating properties. An emerging field is the study of the acoustical properties of multiscale porous materials. An example of these is a granular material in which the particles are porous. In this paper, analytical and hybrid analytical-numerical models describing the acoustical properties of these materials are introduced. Image processing techniques have been employed to estimate characteristic dimensions of the materials. The model predictions are compared with measurements on expanded perlite and activated carbon showing satisfactory agreement. It is concluded that a double porosity granular material exhibits greater low-frequency sound absorption at reduced weight compared to a solid-grain granular material with similar mesoscopic characteristics. PMID:22087905

Venegas, Rodolfo; Umnova, Olga

2011-11-01

204

Sliding through a superlight granular medium  

NASA Astrophysics Data System (ADS)

We explore the penetration dynamics of an intruder in a granular medium composed of expanded polystyrene spherical particles. Three features distinguish our experiment from others studied so far in granular physics: (a) the impact is horizontal, decoupling the effects of gravity and the drag force; (b) the density of the intruder ?i is up to 350 times larger than the density of the granular medium ?m ; and (c) the way the intruder moves through the material, sliding at the bottom of the column with small friction. Under these conditions we find that the final penetration D scales with (?i/?m) and the drag force Fd and D saturate with the height of the granular bed.

Pacheco-Vázquez, F.; Ruiz-Suárez, J. C.

2009-12-01

205

An assessment of granular urea\\/ammonium sulphate and urea\\/potassium nitrate fertilizers on nitrogen recovery by ryegrass  

Microsoft Academic Search

The comparative effects of ammonium sulphate (AS), potassium nitrate (KNO3), urea (U) or combined 1:1 (w\\/w) U\\/KNO3, U\\/AS granular products were investigated on dry matter (DM) yield and15N utilisation by perennial ryegrass grown under controlled environmental conditions.

Catherine J. Watson

1988-01-01

206

Wetting film dynamics and stability  

Microsoft Academic Search

Although the wetting films are similar in many aspects to other thin liquid films, there are some differences in their behavior, too. In contrast to soap and emulsion films, whose surfaces are homogeneous, solid substrates of wetting films are heterogeneous as a rule, unless special measures for their homogenization are taken. Here we mean primarily heterogeneous distribution of surface energy

B. Radoev; K. W. Stoeckelhuber; R. Tsekov; P. Letocart

2011-01-01

207

Extensive wetting due to roughness  

SciTech Connect

Typically, a small mass of eutectic Sn-Pb solder wets a copper surface and flows radially outward to form a hemispherical shape with a contact angle of approx. 15--20 deg. When a similar mass of solder wets and thick electroless copper coated substrate, rapid radial flow commences and surprising new effects occur. Thick coats of electroless copper have a nodular surface structure and spreading on it does not subside until all solder is consumed. When the nodular structure is wetted by solder a coastline'' with many nearby islands'' are defined. Photos of regions at the wetting front were taken in the backscatter imaging mode of an SEM. These images show that solder wets the valleys between the surface nodules forming a delicate, lacy arrangement. The geometry of this coastal'' solder structure is described as fractal-like having a dimension D = 1.38 making it similar to drying fronts and cloud configurations. The importance of surface roughness in wetting phenomena is discussed in the light of an extensive history on the subject. It is shown that for spontaneous flow, assisted by roughness, the surface geometry must consist of local angles that are larger than the equilibrium contact angle. Kinetics of the wetting process are demonstrated by image analysis of wetted area taken from videotaped experiments. These experimental kinetics are shown to be similar in form to flow in open channel capillaries.

Yost, F.G.; Michael, J.R.; Eisenmann, E.T. (Sandia National Labs., Albuquerque, NM (United States). Center for Solder Science and Technology)

1995-01-01

208

Transport Kinetics of Wetting Layers  

Microsoft Academic Search

The transport kinetics of wetting layers of ethanol and propane on silver substrates is investigated by monitoring the temporal decay of pulsed-laser-induced spatial thickness modulations. Our method allows to distinguish between different transport mechanisms, such as direct exchange with the vapour phase, viscous flow within the wetting layer, or surface diffusion. In either case, the activation energy found for the

S. Herminghaus; T. Paatzsch; T. Häcker; P. Leiderer

1995-01-01

209

Aerobic granular sludge—a case report  

Microsoft Academic Search

Aerobic granular sludge was observed in a Sequencing Batch Reactor (SBR) in which a synthetic urban wastewater containing sodium acetate as an organic substrate was fed, and dissolved oxygen (DO) was controlled at low concentration (0.7–1.0mg\\/l) Microscope examination showed that the morphology of the granules was nearly spherical (0.3–0.5mm in diameter) with a very clear outline. The granular sludge had

Peng Dangcong; Nicolas Bernet; Jean-Philippe Delgenes; Rene Moletta

1999-01-01

210

Magnetoresistance of granular ferromagnet-insulator films  

Microsoft Academic Search

We report the GMR-like magnetoresistive behavior of granular ferromagnet-insulator mixtures below the percolation threshold. In contrast with heterogeneous ferromagnet-normal metal systems, the absolute magnitude of the magnetoresistance increases at lower concentrations of the ferromagnetic component, and reaches a field sensitivity ??\\/?H of the order of 10 ? cm T?1. Characteristic features of the GMR in highly resistive granular ferromagnets are

A. Gerber; A. Milner; B. Groisman; M. Karpovski; A. Sulpice

1997-01-01

211

Underwater wet welding of steel  

SciTech Connect

Underwater wet welding is conducted directly in water with the shielded metal arc (SMA) and flux cored arc (FCA) welding processes. Underwater wet welding has been demonstrated as an acceptable repair technique down to 100 meters (325 ft.) in depth, but wet welds have been attempted on carbon steel structures down to 200 meters (650 ft.). The primary purpose of this interpretive report is to document and evaluate current understanding of metallurgical behavior of underwater wet welds so that new welding consumables can be designed and new welding practices can be developed for fabrication and repair of high strength steel structures at greater depths. First the pyrometallurgical and physical metallurgy behaviors of underwater weldments are discussed. Second, modifications of the welding consumables and processes are suggested to enhance the ability to apply wet welding techniques.

Ibarra, S. [Amoco Corporation Research, Naperville, IL (United States); Liu, S.; Olson, D.L. [Colorado School of Mines, Golden, CO (United States)

1995-05-01

212

Querying temporal clinical databases on granular trends.  

PubMed

This paper focuses on the identification of temporal trends involving different granularities in clinical databases, where data are temporal in nature: for example, while follow-up visit data are usually stored at the granularity of working days, queries on these data could require to consider trends either at the granularity of months ("find patients who had an increase of systolic blood pressure within a single month") or at the granularity of weeks ("find patients who had steady states of diastolic blood pressure for more than 3 weeks"). Representing and reasoning properly on temporal clinical data at different granularities are important both to guarantee the efficacy and the quality of care processes and to detect emergency situations. Temporal sequences of data acquired during a care process provide a significant source of information not only to search for a particular value or an event at a specific time, but also to detect some clinically-relevant patterns for temporal data. We propose a general framework for the description and management of temporal trends by considering specific temporal features with respect to the chosen time granularity. Temporal aspects of data are considered within temporal relational databases, first formally by using a temporal extension of the relational calculus, and then by showing how to map these relational expressions to plain SQL queries. Throughout the paper we consider the clinical domain of hemodialysis, where several parameters are periodically sampled during every session. PMID:22155334

Combi, Carlo; Pozzi, Giuseppe; Rossato, Rosalba

2011-12-02

213

Model studies on granular activated carbon adsorption in fixed bed filtration  

Microsoft Academic Search

The removal of natural organic matter (NOM) using a continuous flow fixed bed granular activated carbon (GAC) column was studied and the results were then fitted with the Adams-Bohart, Bed-Depth- Service-Time and Clarks models. The GAC, KI-6070 and KI-8085 used in the study had external surface areas of 277 m2\\/g and 547 m2\\/g, respectively. Adsorption of NOM by the GAC

A. B. Jusoh; M. J. M. M. Noor; S. B. Piow

214

Numerical-linguistic knowledge discovery using granular neural networks  

NASA Astrophysics Data System (ADS)

In this paper, a granular-neural-network-based Knowledge Discovery and Data Mining (KDDM) method based on granular computing, neural computing, fuzzy computing, linguistic computing and pattern recognition is presented. The major issues include (1) how to use neural networks to discover granular knowledge from numerical-linguistic databases, and (2) how to use discovered granular knowledge to predict missing data. A Granular Neural Network (GNN) is designed to deal with numerical-linguistic data fusion and granular knowledge discovery in numerical-linguistic databases. From a data granulation point of view, the GNN can process granular data in a database. From a data fusion point of view, the GNN makes decisions based on different kinds of granular data. From a KDDM point of view, the GNN is able to learn internal granular relations between numerical-linguistic inputs and outputs, and predict new relations in a database.

Zhang, Yanqing

2000-04-01

215

Dynamic Deformation and Collapse of Granular Columns  

NASA Astrophysics Data System (ADS)

Large dynamic deformation of granular materials may be found in nature not only in the failure of slopes and cliffs — due to earthquakes, rock avalanches, debris flows and landslides — but also in earthquake faulting itself. Granular surface flows often consist of solid grains and intergranular fluid, but the effect of the fluid may be usually negligible because the volumetric concentration of grains is in many cases high enough for interparticle forces to dominate momentum transport. Therefore, the investigation of dry granular flow of a mass might assist in further understanding of the above mentioned geophysical events. Here, utilizing a high-speed digital video camera system, we perform a simple yet fully-controlled series of laboratory experiments related to the collapse of granular columns. We record, at an interval of some microseconds, the dynamic transient granular mass flow initiated by abrupt release of a tube that contains dry granular materials. The acrylic tube is partially filled with glass beads and has a cross-section of either a fully- or semi-cylindrical shape. Upon sudden removal of the tube, the granular solid may fragment under the action of its own weight and the particles spread on a rigid horizontal plane. This study is essentially the extension of the previous ones by Lajeunesse et al. (Phys. Fluids 2004) and Uenishi and Tsuji (JPGU 2008), but the striped layers of particles in a semi-cylindrical tube, newly introduced in this contribution, allow us to observe the precise particle movement inside the granular column: The development of slip lines inside the column and the movement of particles against each other can be clearly identified. The major controlling parameters of the spreading dynamics are the initial aspect ratio of the granular (semi-)cylindrical column, the frictional properties of the horizontal plane (substrate) and the size of beads. We show the influence of each parameter on the average flow velocity and final radius and height of the deposit, i.e., the fraction of granular mass mobilized by the flow, and the final shape of the deposit.

Uenishi, K.; Tsuji, K.; Doi, S.

2009-12-01

216

Discrete Element Modeling of Complex Granular Flows  

NASA Astrophysics Data System (ADS)

Granular materials occur almost everywhere in nature, and are actively studied in many fields of research, from food industry to planetary science. One approach to the study of granular media, the continuum approach, attempts to find a constitutive law that determines the material's flow, or strain, under applied stress. The main difficulty with this approach is that granular systems exhibit different behavior under different conditions, behaving at times as an elastic solid (e.g. pile of sand), at times as a viscous fluid (e.g. when poured), or even as a gas (e.g. when shaken). Even if all these physics are accounted for, numerical implementation is made difficult by the wide and often discontinuous ranges in continuum density and sound speed. A different approach is Discrete Element Modeling (DEM). Here the goal is to directly model every grain in the system as a rigid body subject to various body and surface forces. The advantage of this method is that it treats all of the above regimes in the same way, and can easily deal with a system moving back and forth between regimes. But as a granular system typically contains a multitude of individual grains, the direct integration of the system can be very computationally expensive. For this reason most DEM codes are limited to spherical grains of uniform size. However, spherical grains often cannot replicate the behavior of real world granular systems. A simple pile of spherical grains, for example, relies on static friction alone to keep its shape, while in reality a pile of irregular grains can maintain a much steeper angle by interlocking force chains. In the present study we employ a commercial DEM, nVidia's PhysX Engine, originally designed for the game and animation industry, to simulate complex granular flows with irregular, non-spherical grains. This engine runs as a multi threaded process and can be GPU accelerated. We demonstrate the code's ability to physically model granular materials in the three regimes mentioned above: (1) a static and steep granular pile; (2) granular flow with a complex velocity field; and (3) an agitated granular pile resulting in size based segregation. We compare our simulations to laboratory experiments in the first and third regimes, and to a known empirical constitutive law (Jop et al. 2006) in the second. We discuss application of this code in studies of several planetary systems, including analysis of the tensile strength of comets from evidence of tidal disruption, and bulking and banding on rubble-pile asteroids, as an indication of their seismic history.

Movshovitz, N.; Asphaug, E. I.

2010-12-01

217

Aerobic granular sludge: recent advances.  

PubMed

Aerobic granulation, a novel environmental biotechnological process, was increasingly drawing interest of researchers engaging in work in the area of biological wastewater treatment. Developed about one decade ago, it was exciting research work that explored beyond the limits of aerobic wastewater treatment such as treatment of high strength organic wastewaters, bioremediation of toxic aromatic pollutants including phenol, toluene, pyridine and textile dyes, removal of nitrogen, phosphate, sulphate and nuclear waste and adsorption of heavy metals. Despite this intensive research the mechanisms responsible for aerobic granulation and the strategy to expedite the formation of granular sludge, and effects of different operational and environmental factors have not yet been clearly described. This paper provides an up-to-date review on recent research development in aerobic biogranulation technology and applications in treating toxic industrial and municipal wastewaters. Factors affecting granulation, granule characterization, granulation hypotheses, effects of different operational parameters on aerobic granulation, response of aerobic granules to different environmental conditions, their applications in bioremediations, and possible future trends were delineated. The review attempts to shed light on the fundamental understanding in aerobic granulation by newly employed confocal laser scanning microscopic techniques and microscopic observations of granules. PMID:18573633

Adav, Sunil S; Lee, Duu-Jong; Show, Kuan-Yeow; Tay, Joo-Hwa

2008-05-19

218

Chemotaxis of large granular lymphocytes  

SciTech Connect

The hypothesis that large granular lymphocytes (LGL) are capable of directed locomotion (chemotaxis) was tested. A population of LGL isolated from discontinuous Percoll gradients migrated along concentration gradients of N-formyl-methionyl-leucyl-phenylalanine (f-MLP), casein, and C5a, well known chemoattractants for polymorphonuclear leukocytes and monocytes, as well as interferon-..beta.. and colony-stimulating factor. Interleukin 2, tuftsin, platelet-derived growth factor, and fibronectin were inactive. Migratory responses were greater in Percoll fractions with the highest lytic activity and HNK-1/sup +/ cells. The chemotactic response to f-MLP, casein, and C5a was always greater when the chemoattractant was present in greater concentration in the lower compartment of the Boyden chamber. Optimum chemotaxis was observed after a 1 hr incubation that made use of 12 ..mu..m nitrocellulose filters. LGL exhibited a high degree of nondirected locomotion when allowed to migrate for longer periods (> 2 hr), and when cultured in vitro for 24 to 72 hr in the presence or absence of IL 2 containing phytohemagluttinin-conditioned medium. LGL chemotaxis to f-MLP could be inhibited in a dose-dependent manner by the inactive structural analog CBZ-phe-met, and the RNK tumor line specifically bound f-ML(/sup 3/H)P, suggesting that LGL bear receptors for the chemotactic peptide.

Pohajdak, B.; Gomez, J.; Orr, F.W.; Khalil, N.; Talgoy, M.; Greenberg, A.H.

1986-01-01

219

Driven fragmentation of granular gases  

NASA Astrophysics Data System (ADS)

The dynamics of homogeneously heated granular gases which fragment due to particle collisions is analyzed. We introduce a kinetic model which accounts for correlations induced at the grain collisions and analyze both the kinetics and relevant distribution functions these systems develop. The work combines analytical and numerical studies based on direct simulation Monte Carlo calculations. A broad family of fragmentation probabilities is considered, and its implications for the system kinetics are discussed. We show that generically these driven materials evolve asymptotically into a dynamical scaling regime. If the fragmentation probability tends to a constant, the grain number diverges at a finite time, leading to a shattering singularity. If the fragmentation probability vanishes, then the number of grains grows monotonously as a power law. We consider different homogeneous thermostats and show that the kinetics of these systems depends weakly on both the grain inelasticity and driving. We observe that fragmentation plays a relevant role in the shape of the velocity distribution of the particles. When the fragmentation is driven by local stochastic events, the long velocity tail is essentially exponential independently of the heating frequency and the breaking rule. However, for a Lowe-Andersen thermostat, numerical evidence strongly supports the conjecture that the scaled velocity distribution follows a generalized exponential behavior f(c)˜exp(-cn) , with n?1.2 , regarding less the fragmentation mechanisms.

Cruz Hidalgo, Raúl; Pagonabarraga, Ignacio

2008-06-01

220

Persistence of force networks in compressed granular media  

NASA Astrophysics Data System (ADS)

We utilize the tools of persistent homology to analyze features of force networks in dense granular matter, modeled as a collection of circular, inelastic frictional particles. The proposed approach describes these networks in a precise and tractable manner, allowing us to identify features that are difficult or impossible to characterize by other means. In contrast to other techniques that consider each force threshold level separately, persistent homology allows us to consider all threshold levels at once to describe the force network in a complete and insightful manner. We consider continuously compressed system of particles characterized by varied polydispersity and friction in two spatial dimensions. We find significant differences between the force networks in these systems, suggesting that their mechanical response may differ considerably as well.

Kramar, M.; Goullet, A.; Kondic, L.; Mischaikow, K.

2013-04-01

221

Persistence of force networks in compressed granular media.  

PubMed

We utilize the tools of persistent homology to analyze features of force networks in dense granular matter, modeled as a collection of circular, inelastic frictional particles. The proposed approach describes these networks in a precise and tractable manner, allowing us to identify features that are difficult or impossible to characterize by other means. In contrast to other techniques that consider each force threshold level separately, persistent homology allows us to consider all threshold levels at once to describe the force network in a complete and insightful manner. We consider continuously compressed system of particles characterized by varied polydispersity and friction in two spatial dimensions. We find significant differences between the force networks in these systems, suggesting that their mechanical response may differ considerably as well. PMID:23679407

Kramar, M; Goullet, A; Kondic, L; Mischaikow, K

2013-04-22

222

Combined granular-lattice ('Avellino') corneal dystrophy.  

PubMed Central

BACKGROUND/PURPOSE: In 1988, a report was published describing the histopathologic examination of corneal buttons of 4 patients who had undergone unilateral keratoplasty because of decreased vision caused by what had been diagnosed clinically as granular dystrophy. But on pathologic examination, lesions characteristic of both granular dystrophy and lattice dystrophy were found in each of the 4 corneal buttons. The patients came from 3 different families, each of which traced its origin to the Italian province of Avellino. We studied the clinical and histopathological features of 4 corneas affected by combined granular-lattice dystrophy, adding thereby to the total of 12 other corneas that have been so-described in the literature. METHODS: Two women underwent bilateral penetrating keratoplasty for what was diagnosed clinically as Reis-Bücklers dystrophy in the first patient, and as granular dystrophy in the second patient. We studied all 4 corneas pathologically, using both conventional hematoxylin and eosin stains as well as special histochemical techniques. RESULTS: All 4 corneas contained lesions characteristic of both granular dystrophy and lattice dystrophy, a circumstance that has given rise to the name "combined granular-lattice dystrophy." The patients are not known to be of Italian ancestry. CONCLUSIONS: Three clinical signs characterize combined granular-lattice dystrophy: (1) anterior stromal discrete, grayish-white deposits; (2) lattice lesions located in mid-stroma to posterior stroma; and (3) anterior stromal haze. Both clinically and histopathologically, the lattice lesions are of greater diameter than are those that occur in lattice dystrophy type I. In the past few years, striking advances have been made in understanding the genetics of combined granular-lattice dystrophy. The most recent of these was published just 2 months before the 1997 meeting of the American Ophthalmological Society, and establishes a common molecular origin for granular dystrophy, lattice dystrophy type I, Avellino dystrophy, and Reis-Bücklers dystrophy. Images FIGURE 2 FIGURE 3 FIGURE 4 FIGURE 1 FIGURE 5 FIGURE 6 FIGURE 7 FIGURE 8 FIGURE 9 FIGURE 10

Ferry, A P; Benson, W H; Weinberg, R S

1997-01-01

223

Clinical Trials for Wet AMD  

MedlinePLUS

... patients with wet macular degeneration to receive a single injection of a drug designed to interfere with ... when injected at high concentrations. Participants received a single injection of the drug, with some patients receiving ...

224

URBAN WET-WEATHER FLOWS  

EPA Science Inventory

Provides the annual Urban Wet Weather Flow Literture Review for the calendar year 1998 conducted for the Water Environment Federation. It contains hundreds of citations covering the topics of characterization and effects, management, modeling, regulator policies and contol and t...

225

Production of granular ammonium polyphosphate from wet-process phosphoric acid  

Microsoft Academic Search

Although solid ammonium orthophosphates, such as MAP and DAP, are excellent fertilizer materials, the advantages of solid materials containing polyphosphate have been shown, particularly in connection with their use to make fluid fertilizers. The demonstration-scale pipe reactor\\/pug mill process at TVA has produced an excellent product; however, a suitable APP product also can be made with the pipe\\/drum granulator process,

1984-01-01

226

Production of granular ammonium polyphosphate from wet-process phosphoric acid  

SciTech Connect

Although solid ammonium orthophosphates, such as MAP and DAP, are excellent fertilizer materials, the advantages of solid materials containing polyphosphate have been shown, particularly in connection with their use to make fluid fertilizers. The demonstration-scale pipe reactor/pug mill process at TVA has produced an excellent product; however, a suitable APP product also can be made with the pipe/drum granulator process, which is simpler, more economical, and readily adaptable to granulation plants in which pipe-cross reactors have been installed. This APP product is comparable to MAP for direct application and bulk blending, and it produces superior suspensions. The cost of production of APP should be no more than about 1% higher than that for MAP. APP also can be produced from sludge acid. So, it appears that production of APP containing 10% of the P/sub 2/O/sub 5/ as polyphosphate, instead of producing MAP, would be beneficial. TVA is in the process of modifying a TVA demonstration-scale plant to demonstrate the production of APP with the pipe reactor/drum granulator process. This 20-ton-per-hour unit is scheduled to start up in July 1985.

Parker, B.R.

1984-01-01

227

Energy Conservation for Granular Coal Injection into a Blast Furnace  

NASA Astrophysics Data System (ADS)

Due to the lack of knowledge regarding the combustion of granular coal injected into a blast furnace, injection characteristics of granular coal were first studied through proximate analysis, element analysis, and research of explosivity, ignition point, meltability of ash, grindability, calorific value, etc. Using a sampling device in the raceway combined with petrographic analysis, during the combustion process of granular coal with high crystal water and volatile in raceway, cracks and bursts were found, leading to a reduction of particle size. Based on a model of mass control and dynamic theory of particle combustion, the transition dynamic model for cracking in combustion of granular coal was found, and the critical value of cracking ratio (?P) for granular coal combustion in the raceway was calculated. Finally, the utilization ratio and energy efficiency of granular coal used in the blast furnace were discussed, offering theoretical foundation and technical support for intensifying granular coal combustion and promoting granular coal injection.

Guo, Hongwei; Su, Buxin; Zhang, Jianliang; Shao, Jiugang; Zuo, Haibin; Ren, Shan

2012-08-01

228

Wetting induced instabilities in miscible polymer blends  

NASA Astrophysics Data System (ADS)

The behaviour of miscible blends of polystyrene (PS)/poly(vinyl methyl ether)(PVME) of varying compositions has been investigated [1] at temperatures where PS and PVME are miscible. The PVME is seen to enrich the polymer-air surface, forming a layer with a width that is comparable to the correlation length. Further heating close to the demixing temperature results in the formation of a capillary instabilities at the polymer surface exhibiting a spinodal-like pattern with a characteristic wavelength that depends on the blend composition. Formation of these instabilities is seen for all blend compositions. We propose that these wetting induced instabilities result from coupled height and composition fluctuations in the PVME enriched surface layer, driving the build-up of long wavelength fluctuations. [4pt] [1] Thomas, K.R.; Clarke, N.; Poetes, R.; Morariu, M.; Steiner, U.; Soft Matter, 6, 3517, 2010

Clarke, Nigel; Thomas, Katherine; Steiner, Ullrich; Poetes, Rosa; Morariu, Mihai

2011-03-01

229

SETAC-U.S. EPA WET INITIATIVES: ALL WET AND NOTHING BUT WET  

EPA Science Inventory

To ensure that sould scientific principles and sound science are applied to the challenging issues in t he Whole Effluent Toxicity (WET) process, the Society of Environmental Toxicology and Chemistry (SETAC) Foundation for Environmental Education was awarded a cooperative agreem...

230

A unified study on human and Web granular reasoning  

Microsoft Academic Search

In this talk, we will describe studying on granular reasoning of human and Web in a unified way from the viewpoint of brain informatics. We consider Web granular reasoning as an application of human-inspired granular reasoning. As for human granular reasoning, based on the previous studies about basic-level advantage and its reversal effect, we use fMRI\\/ERP to investigate how the

Ning Zhong

2009-01-01

231

Rheology of Dense Sheared Granular Flows  

NASA Astrophysics Data System (ADS)

Rapid granular flows are defined as flows in which the time scales for the particle interactions are small compared to the inverse of the strain rate, so that the particle interactions can be treated as instantaneous collisions. We first show, using Discrete Element simulations, that even very dense flows of sand or glass beads with volume fraction between 0.5 and 0.6 are rapid granular flows. Since collisions are instantaneous, a kinetic theory approach for the constitutive relations is most appropriate, and we present kinetic theory results for different microscopic models for particle interaction. The significant difference between granular flows and normal fluids is that energy is not conserved in a granular flow. The differences in the hydrodynamic modes caused by the non-conserved nature of energy are discussed. Going beyond the Boltzmann equation, the effect of correlations is studied using the ring kinetic approximation, and it is shown that the divergences in the viscometric coefficients, which are present for elastic fluids, are not present for granular flows because energy is not conserved. The hydrodynamic model is applied to the flow down an inclined plane. Since energy is not a conserved variable, the hydrodynamic fields in the bulk of a granular flow are obtained from the mass and momentum conservation equations alone. Energy becomes a relevant variable only in thin `boundary layers' at the boundaries of the flow where there is a balance between the rates of conduction and dissipation. We show that such a hydrodynamic model can predict the salient features of a chute flow, including the flow initiation when the angle of inclination is increased above the `friction angle', the striking lack of observable variation of the volume fraction with height, the observation of a steady flow only for certain restitution coefficients, and the density variations in the boundary layers.

Kumaran, V.

2008-07-01

232

Simulating granular media on the computer  

NASA Astrophysics Data System (ADS)

Granular materials, like sand or powder, can present very intriguing effects. When shaken, sheared or poured they show segregation, convection and spontaneous fluctuations in densities and stresses. I will discuss the modeling of a granular medium on a computer by simulating a packing of elastic spheres via Molecular Dynamics. Dissipation of energy and shear friction at collisions are included. In the physical range the friction coefficient is found to be a linear function of the angle of repose. On a vibrating plate the formation of convection cells due to walls or amplitude modulations can be observed. The onset of fluidization can be determined and is in good agreement with experiments. Segregation of larger particles is found to be always accompanied by convection cells. There is also ample experimental evidence showing the existence of spontaneous density patterns in granular material flowing through pipes or hoppers. The Molecular Dynamics simulations show that these density fluctuations follow a 1/f ? spectrum. I compare this behavior to deterministic one-dimensional traffic models. A model with continuous positions and velocities shows self-organized critical jamming behind a slower car. The experimentally observed effects are also reproduced by Lattice Gas and Boltzmann Lattice Models. Density waves are spontaneously generated when the viscosity has a nonlinear dependence on density which characterizes granular flow. We also briefly sketch a thermodynamic formalism for loose granular material. In a dense packing non-linear acoustic phenomena, like the pressure dependence of the sound velocity are studied. Finally the plastic shear bands occurring in large scale deformations of compactified granular media are investigated using an explicit Lagrangian technique.

Herrmann, H. J.

233

Spatially modulated kinks in shallow granular layers  

NASA Astrophysics Data System (ADS)

We report on the experimental observation of spatially modulated kinks in a shallow one-dimensional fluidized granular layer subjected to a periodic air flow. We show the appearance of these solutions as the layer undergoes a parametric instability. Due to the inherent fluctuations of the granular layer, the kink profile exhibits an effective wavelength, a precursor, which modulates spatially the homogeneous states and drastically modifies the kink dynamics. We characterize the average and fluctuating properties of this solution. Finally, we show that the temporal evolution of these kinks is dominated by a hopping dynamics, related directly to the underlying spatial structure.

Macías, J. E.; Clerc, M. G.; Falcón, C.; García-Ñustes, M. A.

2013-08-01

234

How granularity issues concern biomedical ontology integration.  

PubMed

The application of upper ontologies has been repeatedly advocated for supporting interoperability between domain ontologies in order to facilitate shared data use both within and across disciplines. We have developed BioTop as a top-domain ontology to integrate more specialized ontologies in the biomolecular and biomedical domain. In this paper, we report on concrete integration problems of this ontology with the domain-independent Basic Formal Ontology (BFO) concerning the issue of fiat and aggregated objects in the context of different granularity levels. We conclude that the third BFO level must be ignored in order not to obviate cross-granularity integration. PMID:18487840

Schulz, Stefan; Boeker, Martin; Stenzhorn, Holger

2008-01-01

235

Spatially modulated kinks in shallow granular layers.  

PubMed

We report on the experimental observation of spatially modulated kinks in a shallow one-dimensional fluidized granular layer subjected to a periodic air flow. We show the appearance of these solutions as the layer undergoes a parametric instability. Due to the inherent fluctuations of the granular layer, the kink profile exhibits an effective wavelength, a precursor, which modulates spatially the homogeneous states and drastically modifies the kink dynamics. We characterize the average and fluctuating properties of this solution. Finally, we show that the temporal evolution of these kinks is dominated by a hopping dynamics, related directly to the underlying spatial structure. PMID:24032762

Macías, J E; Clerc, M G; Falcón, C; García-Ñustes, M A

2013-08-19

236

Rheology of dense granular mixtures: boundary pressures.  

PubMed

Models for dense sheared granular materials indicate that their rheological properties depend on particle size, but the representative size for mixtures is not obvious. Here, we computationally study pressure on a boundary due to sheared granular mixtures to determine its dependence on particle size distribution. We find that the pressure does not depend monotonically on average particle size. Instead it has an additional dependence on a measure of the effective free volume per particle we adapt from an expression for packing of monosized particles near the jammed state. PMID:21405443

Hill, K M; Yohannes, B

2011-02-04

237

Universal response of optimal granular damping devices  

NASA Astrophysics Data System (ADS)

Granular damping devices constitute an emerging technology for the attenuation of vibrations based on the dissipative nature of particle collisions. We show that the performance of such devices is independent of the material properties of the particles for working conditions where damping is optimal. Even the suppression of a dissipation mode (collisional or frictional) is unable to alter the response. We explain this phenomenon in terms of the inelastic collapse of granular materials. These findings provide a crucial standpoint for the design of such devices in order to achieve the desired low maintenance feature that makes particle dampers particularly suitable to harsh environments.

Sánchez, Martín; Rosenthal, Gustavo; Pugnaloni, Luis A.

2012-09-01

238

Periodic Traveling Waves in Diatomic Granular Chains  

NASA Astrophysics Data System (ADS)

We study bifurcations of periodic traveling waves in diatomic granular chains from the anti-continuum limit, when the mass ratio between the light and heavy beads is zero. We show that every limiting periodic wave is uniquely continued with respect to the mass ratio parameter, and the periodic waves with a wavelength larger than a certain critical value are spectrally stable. Numerical computations are developed to study how this solution family is continued to the limit of equal mass ratio between the beads, where periodic traveling waves of homogeneous granular chains exist.

Betti, Matthew; Pelinovsky, Dmitry E.

2013-10-01

239

A Study of Effective Soil Compaction Control of Granular Soils  

Microsoft Academic Search

Although it is known that impact compaction tests are not appropriate for granular soils, these tests continue to be widely used. Excessive settlements frequently occur in granular soils where specified field compaction is based on Standard Proctor (ASTM D 698; AASHTO T 99) maximum dry unit weights. A laboratory test program evaluated alternative test methods for granular soil compaction control

Vincent P. Drnevich; Aaron C. Evans; Adam Buser Prochaska

2007-01-01

240

A Dissipative Coulomb Model for Dense Granular Flows  

Microsoft Academic Search

We address the slow, dense flow of granular materials as a continuum with the incompressible Navier-Stokes equations plus the fluctuating energy balance including granular temperature. The pseudo-fluid is given an apparent viscosity which depends on an order parameter which we choose to be granular temperature. We derive the fluctuating energy balance following Babic [1] this balance includes a `mobility enhancing'

Riccardo Artoni; Andrea Santomaso; Paolo Canu

2008-01-01

241

Drag Force In Granular Media: Analog to Viscosity?  

Microsoft Academic Search

An analogy is often drawn between the behavior granular media and that of fluids, since granular media flow when poured and also conform to the shapes of their containers. Furthermore, when a solid object is pulled through a granular medium, it encounters a drag force resisting its motion which is analogous to the viscous drag force on a solid object

Peter Schiffer; Mark Pfeifer; Reka Albert; Albert-Laszlo Barabasi

1998-01-01

242

Particle scale investigation of flow and mixing of wet particles in rotating drums  

NASA Astrophysics Data System (ADS)

Granular flow in rotating drums exhibits complex phenomena which are further complicated by the presence of liquids. This paper reviews our recent work on flow of wet particles in rotating drums based on the discrete element method (DEM) simulations. The DEM model was validated by comparing the simulation results with experimental measurements. Particle flow at quasi-static and dynamic states was investigated. In the quasi-static state with the drum rotating at low speeds, wet particle bed failed through avalanche and slow structural change was identified prior to the avalanches. In the dynamic state, flow transited from continuous to avalanche flow with increasing liquid surface tension and a plug flow was developed on the bed surface. Particle mixing in both transverse and axial directions was studied. While cohesion in general reduced transverse mixing, enhanced mixing of wet particles was also observed, which was explained by a theory based on particle circulation period. On the other hand, the axial mixing was well described by Fick's law of diffusion and particle diffusivity decreased with increasing cohesion. A correlation was observed between particle diffusivity and granular temperature.

Liu, P. Y.; Yang, R. Y.; Yu, A. B.

2013-06-01

243

Effects of bleaching and nutrient supplementation on wet weight in the jellyfish Cassiopea xamachana (Bigelow) (Cnidaria: Scyphozoa)  

Microsoft Academic Search

Cassiopea xamachana were bleached by elevated temperature or held in complete darkness. Wet weight was measured over several weeks in bleached and unbleached individuals with or without addition of dissolved organic matter (DOM) and\\/or particulate organic matter (POM) in a three-factor experiment. Wet weight decreased to a greater extent in temperature-bleached individuals compared to unbleached individuals. Bleaching by darkness produced

Cheryl J. McGill; Christopher M. Pomory

2008-01-01

244

`Granular Elasticity' and the loss of elastic stability in granular materials  

NASA Astrophysics Data System (ADS)

A recently proposed hyperelastic model for granular materials, called ``granular elasticity,'' identifies a yield angle as a result of thermodynamic instability. GE gives yield angles that are smaller than those found in real materials; a generalization of the theory is considered here that includes dependence on the third strain invariant. This generalization proves unsuccessful, as it gives smaller, not larger, yield angles. Fully convex hyperelastic models are identified as a point for future investigation.

Humrickhouse, Paul W.

2009-06-01

245

Granular cell tumor--clinically presented as lymphadenopathy.  

PubMed

Granular cell tumors are relatively uncommon benign lesions occurring in almost any part of the body. We report the cytological diagnosis of granular cell tumor in 25-year-old male patient who presented with an inguinal mass clinically suspected to be a lymphadenopathy. Fine needle aspiration revealed polygonal cells with abundant, granular cytoplasm and eccentrically located vesicular nuclei and inconspicuous nucleoli. The histopathological examination of the surgical excision confirmed the diagnosis. If resection is complete, local surgical excision is curative for benign granular cell tumors. Granular cell tumor has a characteristic cytological appearance, and fine-needle aspiration cytology has been suggested to be diagnostic modality of choice. PMID:20432759

Loncar, Branka; Marjanovi?, Ksenija; Pauzar, Biljana; Staklenac, Blazenka

2010-03-01

246

Crossover from negative to positive shear rate dependence in granular friction  

NASA Astrophysics Data System (ADS)

Abstract The frictional properties of <span class="hlt">granular</span> <span class="hlt">matter</span> are important for analyzing various phenomena in geosciences. Here, we conduct an experiment on the shear-rate dependence of the friction coefficient, which determines the stability of <span class="hlt">granular</span> flow. By changing the shear rate over four orders of magnitude, we find the characteristic rate at which the least friction is realized associated with the crossover from negative to positive shear rate dependence. The least friction is explained in terms of the competition between two very different physical processes, namely frictional healing and anelasticity. We determine the expression of the characteristic shear rate, which is proportional to the square root of the normal stress.</p> <div class="credits"> <p class="dwt_author">Kuwano, Osamu; Ando, Ryosuke; Hatano, Takahiro</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-04-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">247</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012PhRvL.109w8001B"> <span id="translatedtitle">Interdependence of the Volume and Stress Ensembles and Equipartition in Statistical Mechanics of <span class="hlt">Granular</span> Systems</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We discuss the statistical mechanics of <span class="hlt">granular</span> <span class="hlt">matter</span> and derive several significant results. First, we show that, contrary to common belief, the volume and stress ensembles are interdependent, necessitating the use of both. We use the combined ensemble to calculate explicitly expectation values of structural and stress-related quantities for two-dimensional systems. We thence demonstrate that structural properties may depend on the angoricity tensor and that stress-based quantities may depend on the compactivity. This calls into question previous statistical mechanical analyses of static <span class="hlt">granular</span> systems and related derivations of expectation values. Second, we establish the existence of an intriguing equipartition principle—the total volume is shared equally amongst both structural and stress-related degrees of freedom. Third, we derive an expression for the compactivity that makes it possible to quantify it from macroscopic measurements.</p> <div class="credits"> <p class="dwt_author">Blumenfeld, Raphael; Jordan, Joe F.; Edwards, Sam F.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">248</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/52208165"> <span id="translatedtitle">Low temperature transport in <span class="hlt">granular</span> metals</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">We investigate transport in a <span class="hlt">granular</span> metallic system at large tunneling conductance between the grains. We show that at low temperatures, $T\\\\leq g_T\\\\delta $, where $\\\\delta$ is the single mean energy level spacing in a grain, the coherent electron motion at large distances dominates the physics, contrary to the high temperature ($T > g_T \\\\delta $) behavior where conductivity is</p> <div class="credits"> <p class="dwt_author">I. S. Beloborodov; K. B. Efetov; A. V. Lopatin; V. M. Vinokur</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">249</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/6494023"> <span id="translatedtitle">Optimal design of composite <span class="hlt">granular</span> protectors</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">We employ an evolutionary algorithm to investigate the optimal design of composite protectors using one-dimensional <span class="hlt">granular</span> chains composed of beads of various sizes, masses, and stiffnesses. We define a fitness function using the maximum force transmitted from the protector to a \\</p> <div class="credits"> <p class="dwt_author">Fernando Fraternali; Mason A. Porter; Chiara Daraio</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">250</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/23679406"> <span id="translatedtitle">Localized fluidization in a <span class="hlt">granular</span> medium.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">We present here experimental results on the progressive development of a fluidized zone in a bed of grains, immersed in a liquid, under the effect of a localized upward flow injected through a small orifice at the bottom of the bed. Visualization inside the model <span class="hlt">granular</span> medium consisting of glass beads is made possible by the combined use of two optical techniques: refractive index matching between the liquid and the beads and planar laser-induced fluorescence. Gradually increasing the injection rate, three regimes are successively observed: static bed, fluidized cavity that does not open to the upper surface of the <span class="hlt">granular</span> bed, and finally fluidization over the entire height of the <span class="hlt">granular</span> bed inside a fluidized chimney. The phase diagram is plotted and partially interpreted using a model previously developed by Zoueshtiagh and Merlen [F. Zoueshtiagh and A. Merlen, Phys. Rev. E 75, 053613 (2007)]. A typical sequence, where the flow rate is first increased and then decreased back to zero, reveals a strong hysteretic behavior since the stability of the fluidized cavity is considerably strengthened during the defluidization phase. This effect can be explained by the formation of force arches within the <span class="hlt">granular</span> packing when the chimney closes up at the top of the bed. A study of the expansion rate of the fluidized cavity was also conducted as well as the analysis of the interaction between two injection orifices with respect to their spacing. PMID:23679406</p> <div class="credits"> <p class="dwt_author">Philippe, P; Badiane, M</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-04-18</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">251</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/51929560"> <span id="translatedtitle">The dynamics of <span class="hlt">granular</span> impact cratering</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary"><span class="hlt">Granular</span> media can exhibit both solid- and liquid-like behavior. This is familiar in everyday life, and underlies a wealth of applications and geophysical phenomena. One simple laboratory experiment to quantify this is to drop a ball into a bucket of sand, and to study the scaling of penetration vs system parameters. Earlier we discovered that the penetration is proportional to</p> <div class="credits"> <p class="dwt_author">D. Durian; H. Katsuragi</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">252</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/51705018"> <span id="translatedtitle">Velocity dispersion in <span class="hlt">granular</span> marine sediment</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Acoustic wave velocity dispersion in <span class="hlt">granular</span> marine sediment is important to the study of sediment acoustics. The reported dispersion results cannot be explained with Biot's model using constant Biot parameters. In this study, the acoustic wave velocities in water-saturated glass beads and beach sands with different grain sizes are measured at different frequencies. The velocities in air-saturated same media and</p> <div class="credits"> <p class="dwt_author">Masao Kimura</p> <p class="dwt_publisher"></p> <p class="publishDate">2002-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">253</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ime.auc.dk/nscm15/pdf/nscm15_40.pdf"> <span id="translatedtitle">On Solitons in Dilatant <span class="hlt">Granular</span> Materials</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Summary Wave propagation in dilatant <span class="hlt">granular</span> materials is studied making use of a hierarchical Korteweg-de Vries type evolution equation. This model equation is derived by Giovine and Oliveri in (1). The model equation is solved numerically under harmonic initial conditions. The behaviour of the solution is described and analysed over wide range of material parameters (two dispersion parameters and one</p> <div class="credits"> <p class="dwt_author">L. Ilison; A. Salupere</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">254</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2002JPCM...14.1489B"> <span id="translatedtitle">Memory effects in vibrated <span class="hlt">granular</span> systems</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary"><span class="hlt">Granular</span> materials present memory effects when subjected to tapping processes. These effects have been observed experimentally and are discussed here in the context of a general kind of model system for compaction formulated at a mesoscopic level. The theoretical predictions agree qualitatively with the experimental results. As an example, a particularly simple model is used for detailed calculations.</p> <div class="credits"> <p class="dwt_author">Brey, J. Javier; Prados, A.</p> <p class="dwt_publisher"></p> <p class="publishDate">2002-02-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">255</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://oaspub.epa.gov/eims/eimsapi.dispdetail?deid=49879"> <span id="translatedtitle">ENGINEERING BULLETIN: <span class="hlt">GRANULAR</span> ACTIVATED CARBON TREATMENT</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p class="result-summary"><span class="hlt">Granular</span> activated carbon (GAC) treatment is a physicochemical process that removes a wide variety of contaminants by adsorbing them from liquid and gas streams [1, p. 6-3]. This treatment is most commonly used to separate organic contaminants from water or air; however, it can b...</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">256</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://eric.ed.gov/?q=%22acceleration%22&pg=3&id=EJ963892"> <span id="translatedtitle"><span class="hlt">Granular</span> Gas in a Periodic Lattice</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p class="result-summary">|Glass beads are placed in the compartments of a horizontal square grid. This grid is then vertically shaken. According to the reduced acceleration [image omitted] of the system, the <span class="hlt">granular</span> material exhibits various behaviours. By counting the number of beads in each compartment after shaking, it is possible to define three regimes. At low…</p> <div class="credits"> <p class="dwt_author">Dorbolo, S.; Brandenbourger, M.; Damanet, F.; Dister, H.; Ludewig, F.; Terwagne, D.; Lumay, G.; Vandewalle, N.</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">257</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/55109278"> <span id="translatedtitle">Drag Force and Penetration in <span class="hlt">Granular</span> Media</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The motion of a solid object being pulled slowly through a <span class="hlt">granular</span> medium is resisted by jamming of the grains, resulting in a drag force which differs dramatically from viscous drag in a fluid both in its average properties and in having large fluctuations with distinct characteristics. The drag process thus provides an excellent test-bed for the strength of locally</p> <div class="credits"> <p class="dwt_author">Peter Schiffer; Yeekin Tsui; Istvan Albert; Albert-Laszlo Barabasi</p> <p class="dwt_publisher"></p> <p class="publishDate">2002-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">258</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013AIPC.1542.1250K"> <span id="translatedtitle">Multi-scale modelling of <span class="hlt">granular</span> avalanches</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Avalanches, debris flows, and landslides are geophysical hazards, which involve rapid mass movement of <span class="hlt">granular</span> solids, water and air as a single-phase system. The dynamics of a <span class="hlt">granular</span> flow involve at least three distinct scales: the micro-scale, meso-scale, and the macro-scale. This study aims to understand the ability of continuum models to capture the micro-mechanics of dry <span class="hlt">granular</span> collapse. Material Point Method (MPM), a hybrid Lagrangian and Eulerian approach, with Mohr-Coulomb failure criterion is used to describe the continuum behaviour of <span class="hlt">granular</span> column collapse, while the micromechanics is captured using Discrete Element Method (DEM) with tangential contact force model. The run-out profile predicted by the continuum simulations matches with DEM simulations for columns with small aspect ratios (`h/r' < 2), however MPM predicts larger run-out distances for columns with higher aspect ratios (`h/r' > 2). Energy evolution studies in DEM simulations reveal higher collisional dissipation in the initial free-fall regime for tall columns. The lack of a collisional energy dissipation mechanism in MPM simulations results in larger run-out distances. Micro-structural effects, such as shear band formations, were observed both in DEM and MPM simulations. A sliding flow regime is observed above the distinct passive zone at the core of the column. Velocity profiles obtained from both the scales are compared to understand the reason for a slow flow run-out mobilization in MPM simulations.</p> <div class="credits"> <p class="dwt_author">Kumar, Krishna; Soga, Kenichi; Delenne, Jean-Yves</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-06-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">259</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2001AIPC..578..904G"> <span id="translatedtitle">Energy flow with high <span class="hlt">granularity</span> calorimeters</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">In order to perform high precision measurements as well as search for new phenomena at a next Linear Collider, excellent ENERGY FLOW is mandatory. High <span class="hlt">granularity</span> calorimeters design will fulfill the requests and preliminary results are presented as well as further directions to reach the final performances. .</p> <div class="credits"> <p class="dwt_author">Gay, P.</p> <p class="dwt_publisher"></p> <p class="publishDate">2001-07-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">260</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/12541653"> <span id="translatedtitle">Effective boundary conditions for dense <span class="hlt">granular</span> flows</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">We derive an effective boundary condition for dense <span class="hlt">granular</span> flow taking into account the effect of the heterogeneity of the force network on sliding friction dynamics. This yields an intermediate boundary condition which lies in the limit between no slip and Coulomb friction; two simple functions relating wall stress, velocity, and velocity variance are found from numerical simulations. Moreover, we</p> <div class="credits"> <p class="dwt_author">Riccardo Artoni; Andrea Santomaso; Paolo Canu</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-01-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_12");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> 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src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">261</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://oaspub.epa.gov/eims/eimsapi.dispdetail?deid=41661"> <span id="translatedtitle">DOWNFLOW <span class="hlt">GRANULAR</span> FILTRATION OF ACTIVATED SLUDGE EFFLUENTS</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p class="result-summary">The performance of downflow <span class="hlt">granular</span> filters subjected to effluents from activated sludge processes was investigated at the EPA-DC Pilot Plant in Washington, D.C. Several media combinations were investigated, including both single anthracite and dual anthracite-sand configuration...</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">262</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/59513273"> <span id="translatedtitle">Structure and stability of methanogenic <span class="hlt">granular</span> sludge</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Immobilization of anaerobic bacteria was essential for the development of high rate anaerobic systems for the treatment of waste waters. The most widely applied anaerobic reactor type in which solids retention time is uncoupled from the hydraulic retention time is the Upflow Anaerobic Sludge Blanket (UASB) reactor. In this reactor type methanogenic <span class="hlt">granular</span> sludge is formed by self-immobilization of methanogenic</p> <div class="credits"> <p class="dwt_author">J. T. C. Grotenhuis</p> <p class="dwt_publisher"></p> <p class="publishDate">1992-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">263</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2007PhRvE..75d1301K"> <span id="translatedtitle">Stochastic flow rule for <span class="hlt">granular</span> materials</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">There have been many attempts to derive continuum models for dense <span class="hlt">granular</span> flow, but a general theory is still lacking. Here, we start with Mohr-Coulomb plasticity for quasi-two-dimensional <span class="hlt">granular</span> materials to calculate (average) stresses and slip planes, but we propose a “stochastic flow rule” (SFR) to replace the principle of coaxiality in classical plasticity. The SFR takes into account two crucial features of <span class="hlt">granular</span> materials—discreteness and randomness—via diffusing “spots” of local fluidization, which act as carriers of plasticity. We postulate that spots perform random walks biased along slip lines with a drift direction determined by the stress imbalance upon a local switch from static to dynamic friction. In the continuum limit (based on a Fokker-Planck equation for the spot concentration), this simple model is able to predict a variety of <span class="hlt">granular</span> flow profiles in flat-bottom silos, annular Couette cells, flowing heaps, and plate-dragging experiments—with essentially no fitting parameters—although it is only expected to function where material is at incipient failure and slip lines are inadmissible. For special cases of admissible slip lines, such as plate dragging under a heavy load or flow down an inclined plane, we postulate a transition to rate-dependent Bagnold rheology, where flow occurs by sliding shear planes. With different yield criteria, the SFR provides a general framework for multiscale modeling of plasticity in amorphous materials, cycling between continuum limit-state stress calculations, mesoscale spot random walks, and microscopic particle relaxation.</p> <div class="credits"> <p class="dwt_author">Kamrin, Ken; Bazant, Martin Z.</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-04-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">264</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/15268334"> <span id="translatedtitle">Squeezing <span class="hlt">wetting</span> and nonwetting liquids.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">We present molecular-dynamics results for the squeezing of octane (C8H18) between two approaching solid elastic walls with different <span class="hlt">wetting</span> properties. The interaction energy between the octane bead units and the solid walls is varied from a very small value (1 meV), corresponding to a nonwetting surface with a very large contact angle (nearly 180 degrees), to a high value (18.6 meV) corresponding to complete <span class="hlt">wetting</span>. When at least one of the solid walls is <span class="hlt">wetted</span> by octane we observe well defined molecular layers develop in the lubricant film when the thickness of the film is of the order of a few atomic diameters. An external squeezing-pressure induces discontinuous, thermally activated changes in the number n of lubricant layers (n-->n-1 layering transitions). With increasing interaction energy between the octane bead units and the solid walls, the transitions from n to n-1 layers occur at higher average pressure. This results from the increasing activation barrier to nucleate the squeeze-out with increasing lubricant-wall binding energy (per unit surface area) in the contact zone. Thus, strongly <span class="hlt">wetting</span> lubricant fluids are better boundary lubricants than the less <span class="hlt">wetting</span> ones, and this should result in less wear. We analyze in detail the effect of capillary bridge formation (in the <span class="hlt">wetting</span> case) and droplets formation (in the nonwetting case) on the forces exerted by the lubricant on the walls. For the latter case small liquid droplets may be trapped at the interface, resulting in a repulsive force between the walls during squeezing, until the solid walls come into direct contact, where the wall-wall interaction may be initially attractive. This effect is made use of in some practical applications, and we give one illustration involving conditioners for hair care application. PMID:15268334</p> <div class="credits"> <p class="dwt_author">Samoilov, V N; Persson, B N J</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-01-22</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">265</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012PhDT.......145T"> <span id="translatedtitle">Rheology of Dense <span class="hlt">Granular</span> Mixtures and Slurries</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Dense <span class="hlt">granular</span> flows, characterized by multiple contacts between grains, are common in many industrial processes and natural events, such as debris flows. Understanding the characteristics of these flows is crucial to predict quantities such as bedrock erosion and distance traveled by debris flows. However, the rheological properties of these flows are complicated due to wide particle size distribution and presence of interstitial fluids. Models for dense sheared <span class="hlt">granular</span> materials indicate that their rheological properties depend on particle size, but the representative particle size for mixtures is not obvious. Using the discrete element method (DEM) we study sheared <span class="hlt">granular</span> binary mixtures in a Couette cell to determine the relationship and rheological parameters such as stress and effective coefficient of friction and particle size distribution. The results indicate that the stress does not depend monotonically on the average particle size as it does in models derived from simple dimensional consideration. The stress has an additional dependence on a measure of the effective free volume per particle that is adapted from an expression for packing of monosized particles near the jammed state. The effective friction also has a complicated dependence on particle size distribution. For these systems of relatively hard particles, these relationships are governed largely by the ratio between average collision times and mean-free-path times. The characteristics of shallow free surface flows, important for applications such as debris flows, are different from confined systems. To address this, we also study shallow <span class="hlt">granular</span> flows in a rotating drum. The stress at the boundary, height profiles and segregation patterns from DEM simulations are quantitatively similar to the results obtained from physical experiments of shallow <span class="hlt">granular</span> flows in rotating drums. Individual particle-bed impacts rather than enduring contacts dominate the largest forces on the drum bed, which vary as the grain size squared and the 1.2 power of particle-bed impact velocity. In the presence of interstitial fluids (water + fine particles) these characteristics might change significantly. Modeling particle-particle and fluid-particle interaction in dense <span class="hlt">granular</span> flows is still a challenge. We propose a modification to the DEM to account for specific effects of the interstitial fluid on the dynamics of certain <span class="hlt">granular</span> fluid flows. The results from this simple model are qualitatively similar to results from experiments.</p> <div class="credits"> <p class="dwt_author">Tewoldebrhan, Bereket Yohannes</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">266</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2010EGUGA..1211455D"> <span id="translatedtitle">Dimpling in loose <span class="hlt">granular</span> sediments</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Dimpling is the name given to the centimetre-scale collapse of <span class="hlt">granular</span> deposits covering the interior of alteration shelters in semi-arid badlands. The development of micro-collapses is favoured by the stable conditions found in these shelters, where they are safe from water flows, rain impact, and animal or human traffic. The floor of these shelters is usually covered by several centimetres of sandy sediment resulting from the alteration of the rocky substratum and characterised by apparently very low density and high porosity. We have observed that the dimpling phenomenon does not depend on the mineralogy of the sands and occurs in dry conditions. The dimples are the shapes resulting from this process and are fragile, conical depressions ranging from 1 to 12 cm in diameter. They are generally over 3 cm in depth, depending on the depth of the sandy layer. The dimples can be classified into three groups by diameter (Ø): Ø?1cm, 1cm?Ø?10 cm and Ø?10 cm. These three morphometrical ranges suggest three evolutionary stages of the shapes. The main mechanisms of evolution are the coalescence of neighbouring dimples and the accommodation of the lateral walls towards more open, stable shapes. In this process, the slope of the dimple walls decreases to the angle of equilibrium, or internal friction angle of the sediment, when they acquire a more stable, dense structure. This evolution occurs naturally over several months. The process begins when sufficient sediment with low apparent density accumulates. This takes place by vertical accretion of particles from the shelter walls, which pile up in a stack-of-cards type structure. The increase in weight of the sediment column causes punctual micro-collapses when the limit of the sediment's self-supporting capacity is reached. The process is gravitational. Thermal variations can also condition the structural instability of the sediment due to the dilation-retraction changes undergone by the sediment grains. We can thus establish the following stages of evolution in the dimpling process: 1.Accumulation of deposits detached from the shelter walls by gravity. The sediment has a low apparent density, stack-of-cards inner structure. 2.Punctual micro-collapses of the structure (acicular depressions). Some collapses can be repetitive. 3.Shift to open shapes by lateral widening (conical depressions). This occurs through coalescence of micro-collapses or instability of the lateral walls. 4.Shift to senile shapes (plate-shaped depressions) through instability of the lateral walls. During this stage the shapes would become shallower through accumulation of supply in the bottom of the depression. Throughout this process the angle of the walls of the depression decrease to what we suppose must be the internal friction angle of the sediment.</p> <div class="credits"> <p class="dwt_author">Díaz-Hernández, Jose Luis; Yepes, Jorge</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-05-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">267</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://dx.doi.org/10.1023/A:1015868307494"> <span id="translatedtitle">Supporting user-defined <span class="hlt">granularities</span> in a spatiotemporal conceptual model</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p class="result-summary"><span class="hlt">Granularities</span> are integral to spatial and temporal data. A large number of applications require storage of facts along with their temporal and spatial context, which needs to be expressed in terms of appropriate <span class="hlt">granularities</span>. For many real-world applications, a single <span class="hlt">granularity</span> in the database is insufficient. In order to support any type of spatial or temporal reasoning, the semantics related to <span class="hlt">granularities</span> needs to be embedded in the database. Specifying <span class="hlt">granularities</span> related to facts is an important part of conceptual database design because under-specifying the <span class="hlt">granularity</span> can restrict an application, affect the relative ordering of events and impact the topological relationships. Closely related to <span class="hlt">granularities</span> is indeterminacy, i.e., an occurrence time or location associated with a fact that is not known exactly. In this paper, we present an ontology for spatial <span class="hlt">granularities</span> that is a natural analog of temporal <span class="hlt">granularities</span>. We propose an upward-compatible, annotation-based spatiotemporal conceptual model that can comprehensively capture the semantics related to spatial and temporal <span class="hlt">granularities</span>, and indeterminacy without requiring new spatiotemporal constructs. We specify the formal semantics of this spatiotemporal conceptual model via translation to a conventional conceptual model. To underscore the practical focus of our approach, we describe an on-going case study. We apply our approach to a hydrogeologic application at the United States Geologic Survey and demonstrate that our proposed <span class="hlt">granularity</span>-based spatiotemporal conceptual model is straightforward to use and is comprehensive.</p> <div class="credits"> <p class="dwt_author">Khatri, V.; Ram, S.; Snodgrass, R. T.; O'Brien, G. M.</p> <p class="dwt_publisher"></p> <p class="publishDate">2002-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">268</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013Ap%26SS.346..233S"> <span id="translatedtitle">Five dimensional bulk viscous cosmological model with <span class="hlt">wet</span> dark fluid in general relativity</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">In this paper, we have constructed a five dimensional LRS Bianchi type I cosmological model with <span class="hlt">wet</span> dark fluid (WDF) in general relativity with the <span class="hlt">matter</span> field described as bulk viscosity. It is found that in presence of bulk viscosity an inflationary effective stiff fluid cosmological model is obtained, whereas in absence of bulk viscosity the <span class="hlt">wet</span> dark fluid degenerate to stiff fluid. Some physical and geometrical properties of the model are also discussed.</p> <div class="credits"> <p class="dwt_author">Samanta, G. C.; Dhal, S.; Mishra, B.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-07-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">269</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/61345600"> <span id="translatedtitle">Ceilcote ionizing <span class="hlt">wet</span> scrubber evaluation</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The Ceilcote ionizing <span class="hlt">wet</span> scrubber installed on a refractory brick kiln was evaluated with tests involving particulate mass emission, particle size distribution, and opacity. The overall efficiency was 93% with an average outlet opacity determined with a heated plant process visiometer (PPV) of 8% over a 1.68 m (5.5 ft) path length. The average particle cut diameter of the scrubber</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">1979-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">270</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/57623240"> <span id="translatedtitle">The <span class="hlt">Wet</span>Net project</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The <span class="hlt">Wet</span>Net Project is an international experiment to study mechanisms for the improvement and acceleration of scientific interpretation of remote sensing data through the application of electronic networking and data services. Stimulus for the initiation of the project came during the specification of the requirements for NASA's Earth Observing System Data and Information System (EOSDIS). It was desirable to evaluate</p> <div class="credits"> <p class="dwt_author">James C. Dodge; H. Michael Goodman</p> <p class="dwt_publisher"></p> <p class="publishDate">1994-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">271</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.fibrotools.com/NovelWetProcess.pdf"> <span id="translatedtitle">A NOVEL <span class="hlt">WET</span> PROCESSING TECHNOLOGY</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">We have evaluated the hydrodynamics of current <span class="hlt">wet</span> processing techniques for high density pattern etching. The diffusion layer proved to be the main obstacle for a controlled manufacturing of patterns smaller than 100 microns. The result is a limited line resolution and acuity with unacceptably low yields. By utilizing mechanical action at the interface, a novel technology accelerates the transport</p> <div class="credits"> <p class="dwt_author">Igor Kadija</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">272</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2002mfpt....2..216S"> <span id="translatedtitle">Drag Force and Penetration in <span class="hlt">Granular</span> Media</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The motion of a solid object being pulled slowly through a <span class="hlt">granular</span> medium is resisted by jamming of the grains, resulting in a drag force which differs dramatically from viscous drag in a fluid both in its average properties and in having large fluctuations with distinct characteristics. The drag process thus provides an excellent test-bed for the strength of locally jammed states among the grains and the effects of confinement on the jamming. We have studied the drag force as a function of the velocity, the depth in the medium, the grain size and morphology for a vertical cylinder. The data agree well with theory for spherical media, but show an anomalously strong depth dependence for non-spherical grains. We also study the drag force on discrete objects with circular cross section moving slowly through a spherical <span class="hlt">granular</span> medium. Variations in the geometry of the dragged object change the drag force only by a small fraction relative to shape effects in fluid drag. The drag force depends quadratically on the object's diameter as expected. We do observe, however, a deviation above the expected linear depth dependence, and the magnitude of the deviation is apparently controlled by geometrical factors. We also have studied fluctuations in the drag force experienced by a vertical moving through a <span class="hlt">granular</span> medium. The successive formation and collapse of jammed states give a stick-slip nature to the fluctuations which are periodic at small depths but become 'stepped' at large depths, a transition which we interpret as a consequence of the long-range nature of the force chains and the finite size of our experiment. Very recent work has focused on the effects of solid barriers within the grains on penetration of a <span class="hlt">granular</span> medium. We have studied the force required to insert an object vertically into a <span class="hlt">granular</span> medium, with particular attention to the effect of the bottom boundary. We find that, despite the long range nature of the force chains, the existence of the solid bottom of the <span class="hlt">granular</span> container only affects the force when the inserted object is within a short range of the bottom, and that the roughness of the bottom surface has a strong effect on the force's depth profile. Additional information is included in the original extended abstract.</p> <div class="credits"> <p class="dwt_author">Schiffer, Peter; Tsui, Yeekin; Albert, Istvan; Barabasi, Albert-Laszlo</p> <p class="dwt_publisher"></p> <p class="publishDate">2002-11-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">273</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/23757519"> <span id="translatedtitle">The Design of Free Structure <span class="hlt">Granular</span> Mappings: The Use of the Principle of Justifiable <span class="hlt">Granularity</span>.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">The study introduces a concept of mappings realized in presence of information granules and offers a design framework supporting the formation of such mappings. Information granules are conceptually meaningful entities formed on a basis of a large number of experimental input-output numeric data available for the construction of the model. We develop a conceptually and algorithmically sound way of forming information granules. Considering the directional nature of the mapping to be formed, this directionality aspect needs to be taken into account when developing information granules. The property of directionality implies that while the information granules in the input space could be constructed with a great deal of flexibility, the information granules formed in the output space have to inherently relate to those built in the input space. The input space is granulated by running a clustering algorithm; for illustrative purposes, the focus here is on fuzzy clustering realized with the aid of the fuzzy C-means algorithm. The information granules in the output space are constructed with the aid of the principle of justifiable <span class="hlt">granularity</span> (being one of the underlying fundamental conceptual pursuits of <span class="hlt">Granular</span> Computing). The construct exhibits two important features. First, the constructed information granules are formed in the presence of information granules already constructed in the input space (and this realization is reflective of the direction of the mapping from the input to the output space). Second, the principle of justifiable <span class="hlt">granularity</span> does not confine the realization of information granules to a single formalism such as fuzzy sets but helps form the granules expressed any required formalism of information granulation. The quality of the <span class="hlt">granular</span> mapping (viz. the mapping realized for the information granules formed in the input and output spaces) is expressed in terms of the coverage criterion (articulating how well the experimental data are "covered" by information granules produced by the <span class="hlt">granular</span> mapping for any input experimental data). Some parametric studies are reported by quantifying the performance of the <span class="hlt">granular</span> mapping (expressed in terms of the coverage and specificity criteria) versus the values of a certain parameters utilized in the construction of output information granules through the principle of justifiable <span class="hlt">granularity</span>. The plots of coverage-specificity dependency help determine a knee point and reach a sound compromise between these two conflicting requirements imposed on the quality of the <span class="hlt">granular</span> mapping. Furthermore, quantified is the quality of the mapping with regard to the number of information granules (implying a certain <span class="hlt">granularity</span> of the mapping). A series of experiments is reported as well. PMID:23757519</p> <div class="credits"> <p class="dwt_author">Pedrycz, Witold; Al-Hmouz, Rami; Morfeq, Ali; Balamash, Abdullah</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-02-11</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">274</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2008JFM...597..119C"> <span id="translatedtitle"><span class="hlt">Granular</span> hydrodynamics and pattern formation in vertically oscillated <span class="hlt">granular</span> disk layers</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The goal of this study is to demonstrate numerically that certain hydrodynamic systems, derived from inelastic kinetic theory, give fairly good descriptions of rapid <span class="hlt">granular</span> flows even if they are way beyond their supposed validity limits. A numerical hydrodynamic solver is presented for a vibrated <span class="hlt">granular</span> bed in two dimensions. It is based on a highly accurate shock capturing state-of-the-art numerical scheme applied to a compressible Navier-Stokes system for <span class="hlt">granular</span> flow. The hydrodynamic simulation of <span class="hlt">granular</span> flows is challenging, particularly in systems where dilute and dense regions occur at the same time and interact with each other. As a benchmark experiment, we investigate the formation of Faraday waves in a two-dimensional thin layer exposed to vertical vibration in the presence of gravity. The results of the hydrodynamic simulations are compared with those of event-driven molecular dynamics and the overall quantitative agreement is good at the level of the formation and structure of periodic patterns. The accurate numerical scheme for the hydrodynamic description improves the reproduction of the primary onset of patterns compared to previous literature. To our knowledge, these are the first hydrodynamic results for Faraday waves in two-dimensional <span class="hlt">granular</span> beds that accurately predict the wavelengths of the two-dimensional standing waves as a function of the perturbation's amplitude. Movies are available with the online version of the paper.</p> <div class="credits"> <p class="dwt_author">Carrillo, Jos? A.; P?Schel, Thorsten; Salue?A, Clara</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">275</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012AIPC.1501..961B"> <span id="translatedtitle">Heat flux in a <span class="hlt">granular</span> gas</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">A peculiarity of the hydrodynamic Navier-Stokes equations for a <span class="hlt">granular</span> gas is the modification of the Fourier law, with the presence of an additional contribution to the heat flux that is proportional to the density gradient. Consequently, the constitutive relation involves, in the case of a one-component <span class="hlt">granular</span> gas, two transport coefficients: the usual (thermal) heat conductivity and a diffusive heat conductivity. A very simple physical interpretation of this effect, in terms of the mean free path and the mean free time is provided. It leads to the modified Fourier law with an expression for the diffusive Fourier coefficient that differs in a factor of the order of unity from the expression obtained by means of the inelastic Boltzmann equation. Also, some aspects of the Chapman-Enskog computation of the new transport coefficients as well as of the comparison between simulation results and theory are discussed.</p> <div class="credits"> <p class="dwt_author">Brey, J. J.; Ruiz-Montero, M. J.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-11-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">276</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/1999NIMPB.156...30M"> <span id="translatedtitle"><span class="hlt">Granularity</span> controlled irradiation response of cuprate superconductors</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Confining to an energy range where ions can neither create defects through elastic energy loss nor they can create defects through latent track formation, we study the effect of 140MeV Si-ion irradiation in YBa2Cu3O7-x (YBCO). We show that the evolution of superconducting and normal state properties in such situation is largely governed by the initial defects structure, particularly the grain boundary characteristics of the YBCO system. Both intra- and inter-<span class="hlt">granular</span> defect structure in films of two batches were made widely different by having Ag as composite and substituent in one and by aging the other prior to irradiation. Evolution of the resistivity vs temperature characteristics in these films with ion fluence reveals the importance of Ag in bringing about both inter- and intra-<span class="hlt">granular</span> modifications and making the films insensitive to ion irradiation.</p> <div class="credits"> <p class="dwt_author">Mishra, N. C.; Behera, D.; Mohanty, T.; Mohanta, D.; Kanjilal, D.; Mehta, G. K.; Pinto, R.</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">277</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012PhRvL.108q8301K"> <span id="translatedtitle">Nonlocal Constitutive Relation for Steady <span class="hlt">Granular</span> Flow</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Extending recent modeling efforts for emulsions, we propose a nonlocal fluidity relation for flowing <span class="hlt">granular</span> materials, capturing several known finite-size effects observed in steady flow. We express the local Bagnold-type <span class="hlt">granular</span> flow law in terms of a fluidity ratio and then extend it with a particular Laplacian term that is scaled by the grain size. The resulting model is calibrated against a sequence of existing discrete element method data sets for two-dimensional annular shear, where it is shown that the model correctly describes the divergence from a local rheology due to the grain size as well as the rate-independence phenomenon commonly observed in slowly flowing zones. The same law is then applied in two additional inhomogeneous flow geometries, and the predicted velocity profiles are compared against corresponding discrete element method simulations utilizing the same grain composition as before, yielding favorable agreement in each case.</p> <div class="credits"> <p class="dwt_author">Kamrin, Ken; Koval, Georg</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-04-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">278</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/22680912"> <span id="translatedtitle">Nonlocal constitutive relation for steady <span class="hlt">granular</span> flow.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Extending recent modeling efforts for emulsions, we propose a nonlocal fluidity relation for flowing <span class="hlt">granular</span> materials, capturing several known finite-size effects observed in steady flow. We express the local Bagnold-type <span class="hlt">granular</span> flow law in terms of a fluidity ratio and then extend it with a particular Laplacian term that is scaled by the grain size. The resulting model is calibrated against a sequence of existing discrete element method data sets for two-dimensional annular shear, where it is shown that the model correctly describes the divergence from a local rheology due to the grain size as well as the rate-independence phenomenon commonly observed in slowly flowing zones. The same law is then applied in two additional inhomogeneous flow geometries, and the predicted velocity profiles are compared against corresponding discrete element method simulations utilizing the same grain composition as before, yielding favorable agreement in each case. PMID:22680912</p> <div class="credits"> <p class="dwt_author">Kamrin, Ken; Koval, Georg</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-04-26</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">279</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013EL....10214002G"> <span id="translatedtitle"><span class="hlt">Granular</span> Brownian motion with dry friction</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The interplay between Coulomb friction and random excitations is studied experimentally by means of a rotating probe in contact with a stationary <span class="hlt">granular</span> gas. The <span class="hlt">granular</span> material is independently fluidized by a vertical shaker, acting as a “heat bath” for the Brownian-like motion of the probe. Two ball bearings supporting the probe exert nonlinear Coulomb friction upon it. The experimental velocity distribution of the probe, autocorrelation function, and power spectra are compared with the predictions of a linear Boltzmann equation with friction, which is known to simplify in two opposite limits: at high collision frequency, it is mapped to a Fokker-Planck equation with nonlinear friction, whereas at low collision frequency, it is described by a sequence of independent random kicks followed by friction-induced relaxations. Comparison between theory and experiment in these two limits shows good agreement. Deviations are observed at very small velocities, where the real bearings are not well modeled by Coulomb friction.</p> <div class="credits"> <p class="dwt_author">Gnoli, A.; Puglisi, A.; Touchette, H.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-04-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">280</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012JPhCS.382a2026D"> <span id="translatedtitle">Amplitude dependent damping from <span class="hlt">granular</span> viscoelastics</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The ability of a <span class="hlt">granular</span> medium to dissipate vibrational energy is studied at different frequencies and amplitudes. The filler comprises relatively large particles with significant viscoelasticity and is placed in a rectangular box-shaped container and vibrated perpendicular to the direction of gravity. The performance of a model based on wave behaviour that is suitable for very low amplitude vibrations is compared with discrete elements and experimental results. Frequency dependent behaviour for the viscoelastic material is taken into account. The effects of vibration amplitude on performance are considered carefully - especially at the point where particles begin to move relative to each other. One interesting finding is that internal and interface loss mechanisms are closely interrelated - reduction in internal loss increases the mobility of individual particles and therefore more energy dissipation via friction. As a result, the overall effectiveness of the <span class="hlt">granular</span> medium is less sensitive to material and configurationally parameters than might be expected.</p> <div class="credits"> <p class="dwt_author">Darabi, B.; Rongong, J. A.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-08-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_13");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a onClick='return showDiv("page_3");' href="#">3</a> <a onClick='return showDiv("page_4");' 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onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">281</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ntis.gov/search/product.aspx?ABBR=DE98768885"> <span id="translatedtitle"><span class="hlt">Wet</span> flue gas desulfurization and new fuels.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ntis.gov/search/index.aspx">National Technical Information Service (NTIS)</a></p> <p class="result-summary">This thesis describes experimental and theoretical investigations of <span class="hlt">wet</span> flue gas desulfurization (FGD). A review of the current knowledge of the various rate determining steps in <span class="hlt">wet</span> FGD plants is presented. The mechanism underlying the rate of dissoluti...</p> <div class="credits"> <p class="dwt_author">S. Kiil K. Dam-Johansen M. L. Michelsen</p> <p class="dwt_publisher"></p> <p class="publishDate">1998-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">282</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ntis.gov/search/product.aspx?ABBR=N20130008862"> <span id="translatedtitle"><span class="hlt">Wet</span> Chemistry Automated Sample Processing System (WASP).</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ntis.gov/search/index.aspx">National Technical Information Service (NTIS)</a></p> <p class="result-summary">Ball Aerospace & Technologies Corporation (Ball Aerospace) was commissioned by the Jet Propulsion Laboratory (JPL) to produce a <span class="hlt">wet</span> chemistry automated soil sample processing mechanism that can be used for planetary <span class="hlt">wet</span> chemistry sample preparation. O...</p> <div class="credits"> <p class="dwt_author">J. Lasnik J. Soto L. Beegle S. Roark</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">283</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2001APS..DFD.AK002L"> <span id="translatedtitle">Sudden Death of a <span class="hlt">Granular</span> Cluster</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Single clusters in a vibro-fluidized <span class="hlt">granular</span> gas in N connected compartments become unstable at strong shaking. They are experimentally shown to collapse very abruptly. The observed cluster lifetime (as a function of the driving intensity) is analytically calculated within a flux model, making use of the self-similarity of the process. After collapse, the cluster diffuses out into the uniform distribution in a self-similar way, with an anomalous diffusion exponent 1/3.</p> <div class="credits"> <p class="dwt_author">Lohse, Detlef; van der Meer, Devaraj; van der Weele, Ko</p> <p class="dwt_publisher"></p> <p class="publishDate">2001-11-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">284</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/12483495"> <span id="translatedtitle">Low temperature transport in <span class="hlt">granular</span> metals</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">We investigate transport in a <span class="hlt">granular</span> metallic system at large tunneling\\u000aconductance between the grains. We show that at low temperatures, $T\\\\leq\\u000ag_T\\\\delta $, where $\\\\delta$ is the single mean energy level spacing in a grain,\\u000athe coherent electron motion at large distances dominates the physics, contrary\\u000ato the high temperature ($T > g_T \\\\delta $) behavior where conductivity is</p> <div class="credits"> <p class="dwt_author">I. S. Beloborodov; K. B. Efetov; A. V. Lopatin; V. M. Vinokur</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">285</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/48009842"> <span id="translatedtitle">Adhesion analysis of micromycetes on <span class="hlt">granular</span> media</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The efficiency of using <span class="hlt">granular</span> media in the form of sand and mesoporous carbon for the purpose of extracting microscopic\\u000a fungi from water has been estimated. The main factors of micromycetes adhesion on the surface of sorbents were established\\u000a with due regard for the electrokinetic characteristics of fungi cells. The biomass distribution of microscopic fungi over\\u000a the depth of the</p> <div class="credits"> <p class="dwt_author">M. N. Saprykina; N. V. Yaroshevskaya; L. A. Savchina; V. V. Goncharuk</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">286</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/26134025"> <span id="translatedtitle">Segregation on shearing a <span class="hlt">granular</span> material</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Experimental and analytical studies have been made on the kinetic laws of segregation during shearing in unbonded <span class="hlt">granular</span>\\u000a materials in a state of plastic strain. The mechanism of inelastic spherical particle action gives an expression for the driving\\u000a force of the segregation. A method has been developed for determining the segregation coefficient and flow characteristics.\\u000a A mathematical description can be</p> <div class="credits"> <p class="dwt_author">V. N. Dolgunin; V. Ya. Borshchev; R. A. Shubin; A. A. Romanov</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">287</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/17358510"> <span id="translatedtitle">Refraction of shear zones in <span class="hlt">granular</span> materials.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">We study strain localization in slow shear flow focusing on layered <span class="hlt">granular</span> materials. A heretofore unknown effect is presented here. We show that shear zones are refracted at material interfaces in analogy with refraction of light beams in optics. This phenomenon can be obtained as a consequence of a recent variational model of shear zones. The predictions of the model are tested and confirmed by 3D discrete element simulations. We found that shear zones follow Snell's law of light refraction. PMID:17358510</p> <div class="credits"> <p class="dwt_author">Unger, Tamás</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-01-02</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">288</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013ArRMA.208..429B"> <span id="translatedtitle">Uniform Convergence to Equilibrium for <span class="hlt">Granular</span> Media</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We study the long time asymptotics of a nonlinear, nonlocal equation used in the modelling of <span class="hlt">granular</span> media. We prove a uniform exponential convergence to equilibrium for degenerately convex and nonconvex interaction or confinement potentials, improving in particular results by J. A. Carrillo, R. J. McCann and C. Villani. The method is based on studying the dissipation of the Wasserstein distance between a solution and the steady state.</p> <div class="credits"> <p class="dwt_author">Bolley, François; Gentil, Ivan; Guillin, Arnaud</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-05-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">289</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/40348789"> <span id="translatedtitle">Azo dye decolourisation by anaerobic <span class="hlt">granular</span> sludge</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The decolourisation of 20 selected azo dyes by <span class="hlt">granular</span> sludge from an upward-flow anaerobic sludge bed (UASB) reactor was assayed. Complete reduction was found for all azo dyes tested, generally yielding colourless products. The reactions followed first-order kinetics and reaction rates varied greatly between dyes: half-life times ranged from 1 to about 100 h. The slowest reaction rates were found</p> <div class="credits"> <p class="dwt_author">Frank P. van der Zee; Gatze Lettinga; Jim A. Field</p> <p class="dwt_publisher"></p> <p class="publishDate">2001-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">290</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.springerlink.com/index/g3467gu127275840.pdf"> <span id="translatedtitle">An Extended Continuum Theory for <span class="hlt">Granular</span> Media</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">In a dilatant <span class="hlt">granular</span> material with rotating grains the kinetic energy in addition to the usual translational one consists\\u000a of three terms owing to the microstructural motion; in particular, it includes the rotation of granules and the dilatational\\u000a expansion and contraction of the individual (compressible) grains and of the grains relative to one another. Therefore the\\u000a balance and constitutive equations</p> <div class="credits"> <p class="dwt_author">Pasquale Giovine</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">291</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/14098065"> <span id="translatedtitle">Avalanches in anisotropic sheared <span class="hlt">granular</span> media</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">We study the influence of particle shape anisotropy on the occurrence of avalanches in sheared <span class="hlt">granular</span> media. We use molecular\\u000a dynamic simulations to calculate the relative movement of two tectonic plates. Our model considers irregular polygonal particles\\u000a constituting the material within the shear zone. We find that the magnitude of the avalanches is approximately independent\\u000a of particle shape and in</p> <div class="credits"> <p class="dwt_author">Andrés A. Peña; Sean McNamara; Pedro G. Lind; Hans J. Herrmann</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">292</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/976473"> <span id="translatedtitle">Spontaneous spirals in vibrated <span class="hlt">granular</span> chains</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">We present experimental measurements on the spontaneous formation of compact spiral structures in vertically-vibrated <span class="hlt">granular</span> chains. Under weak vibration when the chain is quasi two-dimensional and self-avoiding, spiral structures emerge from random initial configurations. We compare the spiral geometry with that of an ideal tight spiral. Globally, the spiral undergoes a slow rotation such that to keep itself wound, while internally, fast vibrational modes are excited along the backbone with transverse oscillations dominating over longitudinal ones.</p> <div class="credits"> <p class="dwt_author">Ecke, R. E. (Robert E.); Daya, Z. A. (Zahir A.); Rivera, M. K. (Michael K.); Ben-Naim, E. (Eli)</p> <p class="dwt_publisher"></p> <p class="publishDate">2002-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">293</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.paques.nl/documents/papers/PAPER%20340%20-%20Full%20scale%20granular%20sludge%20ANAMMOX%20process.pdf"> <span id="translatedtitle">Full-scale <span class="hlt">granular</span> sludge Anammox process</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The start-up of the first full scale Anammox reactor is complete. The reactor shows stable operation, even at loading rates of 10 kg N\\/m3.d. This performance is the result of the formation of Anammox granules, which have a high density and settling velocities exceeding 100 m\\/h. With this performance, the Anammox <span class="hlt">granular</span> sludge technology has been proven on full scale.</p> <div class="credits"> <p class="dwt_author">W. R. Abma; C. E. Schultz; J. W. Mulder; W. R. L. van der Star; M. Strous; T. Tokutomi; M. C. M. van Loosdrecht</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">294</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2004ZaMP...55..330T"> <span id="translatedtitle">Stress distributions in highly frictional <span class="hlt">granular</span> heaps</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The practice of storing <span class="hlt">granular</span> materials in stock piles occurs throughout the world in many industrial situations. As a result, there is much interest in predicting the stress distribution within a stock pile. In 1981, it was suggested from experimental work that the peak force at the base does not occur directly beneath the vertex of the pile, but at some intermediate point resulting in a ring of maximum pressure. With this in mind, any analytical solution pertaining to this problem has the potential to provide useful insight into this phenomenon. Here, we propose to utilize some recently determined exact parametric solutions of the governing equations for the continuum mechanical theory of <span class="hlt">granular</span> materials for two and three-dimensional stock piles. These solutions are valid provided sin ? = 1, where ? is the angle of internal friction, and we term such materials as ``highly frictional''. We note that there exists materials possessing angles of internal friction around 60 to 65 degrees, resulting in values of sin ? equal to around 0.87 to 0.91. Further, the exact solutions presented here are potentially the leading terms in a perturbation solution for <span class="hlt">granular</span> materials for which 1- sin ? is close to zero. The model assumes that the stock pile is composed of two regions, namely an inner rigid region and an outer yield region. The exact parametric solution is applied to the outer yield region, and the solution is extended continuously into the inner rigid region. The results presented here extend previous work of the authors to the case of highly frictional <span class="hlt">granular</span> solids.</p> <div class="credits"> <p class="dwt_author">Thamwattana, Ngamta; Cox, Grant M.; Hill, James M.</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">295</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/12761352"> <span id="translatedtitle">Collapse and revival of the <span class="hlt">matter</span> wave field of a Bose-Einstein condensate</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">A Bose-Einstein condensate represents the most `classical' form of a <span class="hlt">matter</span> wave, just as an optical laser emits the most classical form of an electromagnetic wave. Nevertheless, the <span class="hlt">matter</span> wave field has a quantized structure owing to the <span class="hlt">granularity</span> of the discrete underlying atoms. Although such a field is usually assumed to be intrinsically stable (apart from incoherent loss processes),</p> <div class="credits"> <p class="dwt_author">Markus Greiner; Olaf Mandel; Theodor W. Hänsch; Immanuel Bloch</p> <p class="dwt_publisher"></p> <p class="publishDate">2002-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">296</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2009APS..SES.HA003D"> <span id="translatedtitle">State variables in dense <span class="hlt">granular</span> materials</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary"><span class="hlt">Granular</span> materials are integral to many parts of our daily lives, from the coffee beans that fuel our mornings to the coal that fuels our power plants. Two related aspects of their dynamics are particularly striking: their ability to exhibit both solid-like and liquid-like behavior, and the presence of highly heterogeneous force chains in which the magnitude of the local stress varies widely over short distances. These distinctive behaviors are connected to the fact that <span class="hlt">granular</span> materials are always out of equilibrium: first, because they are typically both driven and dissipative, but also because they remain in metastable states even when they aren't being driven. I will present recent results from several experiments ranging from the theoretically-motivated (the equilibration of state variables within a non-equilibrium system) to the practical (particle-segregation by size). The results of these experiments elucidate the complex behaviors which underlay <span class="hlt">granular</span> dynamics, and provide a reason to hope that statistical physics might hold the keys to explaining the observed phenomena.</p> <div class="credits"> <p class="dwt_author">Daniels, Karen</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-11-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">297</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013APS..MARN29007B"> <span id="translatedtitle">Detection of Multidimensional Structures in <span class="hlt">Granular</span> Materials</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary"><span class="hlt">Granular</span> media display features across a range of spatial scales, from the particle scale to the force-chain scale and the bulk scale. In contrast to particulate and continuum models, network representations facilitate the simultaneous examination of microscopic, mesoscopic, and macroscopic features. We treat <span class="hlt">granular</span> materials as spatially embedded networks in which the nodes (particles) are connected by weighted edges obtained from contact forces. Using community detection techniques, we identify local 2D geographic domains composed of particles that exert strong forces on one another. We subsequently develop and apply a novel spatial null model constrained by the contact network to extract chain-like structures reminiscent of force chains. We demonstrate that most of these chain-like structures are located close to the center of mass of the 2D geographic domains. However, a minority are located towards the edge of the 2D geographic domains, potentially forming points of instability in <span class="hlt">granular</span> media. We explore the robustness of these detection techniques to algorithmic degeneracies, to simulation versus experimental data, and to varying pressure states.</p> <div class="credits"> <p class="dwt_author">Bassett, Danielle; Daniels, Karen; Owens, Eli; Porter, Mason A.; Manning, M. Lisa</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-03-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">298</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/10105092"> <span id="translatedtitle">Moving <span class="hlt">Granular</span> Bed Filter Development Program</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">The <span class="hlt">granular</span> bed filter was developed through low pressure, high temperature (1600{degrees}F) testing in the late 1970`s and early 1980`s`. Collection efficiencies over 99% were obtained. In 1988, high pressure, high temperature testing was completed at New York University, Westbury, N.Y., utilizing a coal-fired pressurized, fluidized bed combustor. High particulate removal efficiencies were confirmed as it was shown that both New Source Performance Standards and turbine tolerance limits could be met. The early scale-up work of the <span class="hlt">granular</span> bed filter indicated potential limitations due to size, cost, and mechanical complexity. These limitations were addressed in the present program by utilizing the information gained from the filter development up through the NYU test program to reassess the commercial approach. Two studies were chosen for developing conceptual designs and cost estimates of the commercial sized filters. One is the economic study of the 250 MWe, second generation pressurized fluidized bed combustion plant defined by Foster Wheeler. This plant originally included cross-flow filters for hot gas cleanup. The other plant under study is a 100 MWe, airblown KRW gasifier. A cross-flow inter was utilized for gas stream cleanup in this study also. <span class="hlt">Granular</span> bed and ceramic candle filters were substituted for the cross-flow filters in both these plants, and the resulting cost of electricity (COE) is compared.</p> <div class="credits"> <p class="dwt_author">Wilson, K.B.; Haas, J.C.; Eshelman, M.B.</p> <p class="dwt_publisher"></p> <p class="publishDate">1992-11-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">299</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/7146469"> <span id="translatedtitle">Moving <span class="hlt">Granular</span> Bed Filter Development Program</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">The <span class="hlt">granular</span> bed filter was developed through low pressure, high temperature (1600[degrees]F) testing in the late 1970's and early 1980's'. Collection efficiencies over 99% were obtained. In 1988, high pressure, high temperature testing was completed at New York University, Westbury, N.Y., utilizing a coal-fired pressurized, fluidized bed combustor. High particulate removal efficiencies were confirmed as it was shown that both New Source Performance Standards and turbine tolerance limits could be met. The early scale-up work of the <span class="hlt">granular</span> bed filter indicated potential limitations due to size, cost, and mechanical complexity. These limitations were addressed in the present program by utilizing the information gained from the filter development up through the NYU test program to reassess the commercial approach. Two studies were chosen for developing conceptual designs and cost estimates of the commercial sized filters. One is the economic study of the 250 MWe, second generation pressurized fluidized bed combustion plant defined by Foster Wheeler. This plant originally included cross-flow filters for hot gas cleanup. The other plant under study is a 100 MWe, airblown KRW gasifier. A cross-flow inter was utilized for gas stream cleanup in this study also. <span class="hlt">Granular</span> bed and ceramic candle filters were substituted for the cross-flow filters in both these plants, and the resulting cost of electricity (COE) is compared.</p> <div class="credits"> <p class="dwt_author">Wilson, K.B.; Haas, J.C.; Eshelman, M.B.</p> <p class="dwt_publisher"></p> <p class="publishDate">1992-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">300</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/1996APS..DFD..DM06V"> <span id="translatedtitle">Coarsening Transition for Shaken <span class="hlt">Granular</span> Materials</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We describe a coarsening transition which occurs for <span class="hlt">granular</span> materials subject to vertical vibration, z = A \\cos (? t). The traditional control parameter is ? = A?^2/g, where g is the acceleration of gravity. When a layer of <span class="hlt">granular</span> material is shaken with ? > 1, a heap will form (for layer heights large compared to the particle size, d). An alternative control parameter is E = ? (A/d). In a typical rectangular container, a single heap forms by a complex process involving several mechanisms; at this point the convective ``wavelength'', ? is set by the container length, L---? ~= L. We have observed and characterized a new short-? transition to <span class="hlt">granular</span> convection in which the initial instability has ? ~= w << L, where w is the container width. Over time, ? grows until a single heap, ? ~= L remains. The coarsening is characterized by exponential decay of the number crests on the surface of the layer, and the rate for the decay shows critical slowing down as ? arrow ?_onset^+. The onset of the short-? transition is such that E_onset is a universal linearly increasing function of A/d for 0.09mm <= d <= 0.4 mm. This is similar to the onset rule for traveling waves in this system, and may be related to an instability observed in fluidized beds. Specifically, the present instability vanishes if the surrounding air is evacuated.</p> <div class="credits"> <p class="dwt_author">van Doorn, E.; Behringer, R. P.</p> <p class="dwt_publisher"></p> <p class="publishDate">1996-11-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_14");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a onClick='return showDiv("page_3");' href="#">3</a> <a onClick='return showDiv("page_4");' 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onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">301</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2004APS..APRB15005A"> <span id="translatedtitle">Vibratory Shock Compaction of <span class="hlt">Granular</span> Nuclear Waste</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Vibratory Shock Compaction (VSC) is a proven means for quickly forming strong, durable solids from a wide variety of <span class="hlt">granular</span> materials[1]. Calcination of tank and other forms of high level radioactive wastes results in fine <span class="hlt">granular</span> material that is quite amenable to volume reduction and stabilization. We have employed utilities coal ash as a calcine waste surrogate, blended with a quartz/feldspar-rich sand and 0-20% proportions of a borosilicate glass. The blends were compacted at room temperature and fired so that the glass melt could form an efficient binder. Included in the blend are small quantities of three RCRA metals, chromium, cadmium and lead, to permit testing for heavy metal stability. The VSC process is described and the results presented in terms of the waste form dissolution rates, compressive strengths, elastic moduli as determined from resonant frequency measurements, and heavy metal leach rates from Toxicity Characteristic Leaching Procedure measurements. Vibratory shock compaction employing glass binders appears to be a viable alternative to traditional vitrification processes for <span class="hlt">granular</span> waste forms. [1] See http://www.resonantshockcompact.com</p> <div class="credits"> <p class="dwt_author">Amme, Robert C.</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-05-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">302</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/40753840"> <span id="translatedtitle">Surface <span class="hlt">wetness</span> duration under controlled environmental conditions</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Surface <span class="hlt">wetness</span> is an important variable for forecasting plant disease. It is commonly measured with sensors, but these provide an indirect measurement and there is variability between different makes of sensors. Consequently, there is no standard for surface <span class="hlt">wetness</span> measurement. The objective of this study was to derive and validate a physically based theoretical definition of surface <span class="hlt">wetness</span> for both</p> <div class="credits"> <p class="dwt_author">R. D. Magarey; J. M. Russo; R. C. Seem; D. M. Gadoury</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">303</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/22902932"> <span id="translatedtitle">Critical <span class="hlt">wetting</span> concentrations of trisiloxane surfactants</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Trisiloxane surfactants also known as “superspreaders” are characterized by a critical <span class="hlt">wetting</span> concentration (CWC) which has been determined by Svitova et al [T. Svitova, R.M. Hill, Y. Smirnova, A. Stuermer, G. Yakubov, Langmuir 14 (1998) 5023–5031]. CWC is a concentration above which a transition from partial <span class="hlt">wetting</span> to complete <span class="hlt">wetting</span> occurs at spreading over moderately hydrophobic surfaces, hence, the CWC</p> <div class="credits"> <p class="dwt_author">Natalia Ivanova; Victor Starov; Ramon Rubio; Hernán Ritacco; Nidal Hilal; Daniel Johnson</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">304</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.springerlink.com/index/m7p60684tl578543.pdf"> <span id="translatedtitle">Walks, walls, <span class="hlt">wetting</span>, and melting</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">New results concerning the statistics of, in particular,p random walkers on a line whose paths do not cross are reported, extended, and interpreted. A general mechanism yielding phase transitions in one-dimensional or linear systems is recalled and applied to various <span class="hlt">wetting</span> and melting phenomena in (d=2)-dimensional systems, including fluid films and p×1 commensurate adsorbed phases, in which interfaces and domain</p> <div class="credits"> <p class="dwt_author">Michael E. Fisher</p> <p class="dwt_publisher"></p> <p class="publishDate">1984-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">305</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/54323829"> <span id="translatedtitle">Squeezing <span class="hlt">wetting</span> and nonwetting liquids</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">We present molecular-dynamics results for the squeezing of octane (C8H18) between two approaching solid elastic walls with different <span class="hlt">wetting</span> properties. The interaction energy between the octane bead units and the solid walls is varied from a very small value (1 meV), corresponding to a nonwetting surface with a very large contact angle (nearly 180 degrees), to a high value (18.6</p> <div class="credits"> <p class="dwt_author">V. N. Samoilov; B. N. J. Persson</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">306</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/21179703"> <span id="translatedtitle">Importance of <span class="hlt">Granular</span> Structure in the Initial Conditions for the Elliptic Flow</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">We show the effects of the <span class="hlt">granular</span> structure of the initial conditions of a hydrodynamic description of high-energy nucleus-nucleus collisions on some observables, especially on the elliptic-flow parameter v{sub 2}. Such a structure enhances production of isotropically distributed high-p{sub T} particles, making v{sub 2} smaller there. Also, it reduces v{sub 2} in the forward and backward regions where the global <span class="hlt">matter</span> density is smaller and, therefore, where such effects become more efficacious.</p> <div class="credits"> <p class="dwt_author">Andrade, R. P. G.; Grassi, F.; Hama, Y.; Qian, W. L. [Instituto de Fisica, Universidade de Sao Paulo, C.P. 66318, 05315-970 Sao Paulo, Sao Paulo (Brazil); Kodama, T. [Instituto de Fisica, Universidade Federal do Rio de Janeiro, C.P. 68528, 21945-970 Rio de Janeiro, Rio de Janeiro (Brazil)</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-09-12</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">307</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/23697233"> <span id="translatedtitle">Treatment of HMX-production wastewater in an aerobic <span class="hlt">granular</span> reactor.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Aerobic granules were applied to the treatment of HMX-production wastewater using a gradual domestication method in a SBR. During the process, the granules showed a good settling ability, a high biomass retention rate, and high biological activity. After 40 days of stable operation, aerobic <span class="hlt">granular</span> sludge performed very effectively in the removal of carbon and nitrogen compounds from HMX-production wastewater. Organic <span class="hlt">matter</span> removal rates up to 97.57% and nitrogen removal efficiencies up to 80% were achieved during the process. Researchers conclude that using aerobic granules to treat explosive wastewater has good prospects for success. PMID:23697233</p> <div class="credits"> <p class="dwt_author">Zhang, Jin-Hua; Wang, Min-Hui; Zhu, Xiao-Meng</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-04-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">308</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013wbsc.book..145D"> <span id="translatedtitle">Onset of Stationary Flows of a Cohesive <span class="hlt">Granular</span> Material in a Channel</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The handling of bulk materials and powders in process engineering remains an important issue. To obtain reliable gravitational flows, starting and remaining stationary, the hoppers and transport channels must be designed at a scale appropriate for the friction and cohesive properties of the <span class="hlt">granular</span> material. To describe such dense flows (the interaction with the surrounding ambient fluid is negligible compared to the weight of the particles and interparticles forces), they can be modelled by continuum mechanics, associated with a constitutive equation taking into account the friction behaviour (Mohr-Coulomb or Druger-Prager plasticity criterion). We use here the rheology proposed by Jop et al. (Nature 441: 727-730, 2006) which combines this with an associated flow rule (co-linearity of the stress and strain tensors) (Jenike, Powder Technol. 50: 229-236, 1987) and a viscous dependency of the coefficient of friction on the strain (Da Cruz et al., Phys. Rev. E 72: 021309, 2005).Using the method of characteristics to describe the flow structure (de Ryck, <span class="hlt">Granular</span> <span class="hlt">Matter</span> 10: 361-367, 2008), we deduce the minimal slope to obtain a stationary flow of cohesive <span class="hlt">granular</span> materials on a finite width channel, whose lateral walls are rough or smooth. We also obtain the depth of the flow (maximal at the centre of the channel). In the case of weak cohesive materials, these results are formulated with simple analytical expressions.</p> <div class="credits"> <p class="dwt_author">de Ryck, A.; Louisnard, O.</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">309</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/2204256"> <span id="translatedtitle">Temporal Constraints with Multiple <span class="hlt">Granularities</span> in Smart Homes</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">\\u000a In this chapter, we propose a logic-based approach to describe temporal constraints with multiple time <span class="hlt">granularities</span> related\\u000a to events occurring in Smart Homes. We identify a time <span class="hlt">granularity</span> as a (possibly) infinite sequence of time points properly\\u000a labeled with propositional symbols marking the starting and the ending points of each granule. In particular, sensor <span class="hlt">granularities</span> describe time intervals during which</p> <div class="credits"> <p class="dwt_author">Carlo Combi; Rosalba Rossato</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">310</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012APS..MARV52004W"> <span id="translatedtitle">Digging Like Plants: Flexible Intruders in <span class="hlt">Granular</span> Materials</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Inspired by plant root growth in <span class="hlt">granular</span> media, we report on the effects of flexibility on the mechanical work required to dig through <span class="hlt">granular</span> systems. In the case where the digger is significantly thinner than the grain diameter, increased flexibility in one-dimension leads to savings of nearly 50%. A simple numerical model based solely on the variability of forces in the <span class="hlt">granular</span> substrate and the flexibility of the digger gives similar results to those observed in experiments.</p> <div class="credits"> <p class="dwt_author">Wendell, Dawn; Luginbuhl, Katharine; Solano, Diego; Hosoi, Peko</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-02-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">311</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/47902405"> <span id="translatedtitle">Scaling Behaviour of Velocity Fluctuations in Slow <span class="hlt">Granular</span> Flows</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Steric exclusions among particles lead to strong velocity fluctuations in a <span class="hlt">granular</span> flow. Modelling the effective behaviour\\u000a of <span class="hlt">granular</span> materials depends on the extent and scaling properties of these fluctuations. We consider here slow <span class="hlt">granular</span> flows\\u000a of rigid particles simulated by a discrete element method. Bi-periodic boundary conditions allow for macroscopically homogeneous\\u000a shearing up to large strains. We obtain thus</p> <div class="credits"> <p class="dwt_author">Farhang Radjaï; Stéphane Roux</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">312</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/47869195"> <span id="translatedtitle">A Fluctuating Energy Model for Dense <span class="hlt">Granular</span> Flows</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">\\u000a We address the slow, dense flow of <span class="hlt">granular</span> materials as a continuum with the incompressible Navier-Stokes equations plus\\u000a the fluctuating energy balance for <span class="hlt">granular</span> temperature. The pseudo-fluid is given an apparent viscosity, for which we choose\\u000a an Arrhenius-like dependence on <span class="hlt">granular</span> temperature; the fluctuating energy balance includes a ‘mobility enhancing’ term\\u000a due to shear stress and a jamming, dissipative term</p> <div class="credits"> <p class="dwt_author">Riccardo Artoni; Andrea Santomaso; Paolo Canu</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">313</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012PhRvE..86d1308S"> <span id="translatedtitle">Simulation of <span class="hlt">granular</span> jets: Is <span class="hlt">granular</span> flow really a perfect fluid?</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We perform three-dimensional simulations of the impact of a <span class="hlt">granular</span> jet for both frictional and frictionless grains. Small shear stress observed in the experiment [X. Cheng , Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.99.188001 99, 188001 (2007)] is reproduced through our simulation. However, the fluid state after the impact is far from a perfect fluid, and thus the similarity between <span class="hlt">granular</span> jets and quark gluon plasma is superficial because the observed viscosity is finite and its value is consistent with the prediction of the kinetic theory.</p> <div class="credits"> <p class="dwt_author">Sano, Tomohiko G.; Hayakawa, Hisao</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-10-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">314</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2001JChPh.114.2784R"> <span id="translatedtitle"><span class="hlt">Wetting</span> of methanol on the n-alkanes: Observation of short-range critical <span class="hlt">wetting</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We present results of the <span class="hlt">wetting</span> properties of methanol at the liquid-vapor interface of different n-alkanes ranging from hexane to undecane. Measurement of the contact angle shows that, as the bulk critical point is approached, <span class="hlt">wetting</span> transitions occur for long alkanes, whereas drying is found for short alkanes. Measurement of the <span class="hlt">wetting</span> layer thickness, as well as precise contact angle measurements close to the <span class="hlt">wetting</span> temperature Tw, reveal a change in the order of the transition. First order (discontinuous) <span class="hlt">wetting</span> occurs for Tw far from the bulk critical point Tc. Critical (continuous) <span class="hlt">wetting</span> is observed for Tw close to Tc. The observed critical <span class="hlt">wetting</span> transition has all the features of the long-sought short-range critical <span class="hlt">wetting</span> transition. We argue that it is possible to observe short-range critical <span class="hlt">wetting</span> in this system, because the long-range van der Waals interactions are negligible for <span class="hlt">wetting</span> transitions close to the bulk critical point.</p> <div class="credits"> <p class="dwt_author">Ross, David; Bonn, Daniel; Meunier, Jacques</p> <p class="dwt_publisher"></p> <p class="publishDate">2001-02-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">315</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.gpo.gov:80/fdsys/pkg/FR-2011-05-17/pdf/2011-11981.pdf"> <span id="translatedtitle">76 FR 28455 - <span class="hlt">Granular</span> Polytetrafluoroethylene Resin From Italy; Scheduling of an Expedited Five-Year Review...</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.gpo.gov/fdsys/browse/collection.action?collectionCode=FR">Federal Register 2010, 2011, 2012, 2013</a></p> <p class="result-summary">...<span class="hlt">Granular</span> Polytetrafluoroethylene Resin From Italy; Scheduling of an Expedited Five-Year...<span class="hlt">Granular</span> Polytetrafluoroethylene Resin From Italy AGENCY: United States International Trade...<span class="hlt">granular</span> polytetrafluoroethylene resin from Italy would be likely to lead to...</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">2011-05-17</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">316</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.gpo.gov:80/fdsys/pkg/FR-2011-05-12/pdf/2011-11647.pdf"> <span id="translatedtitle">76 FR 27663 - <span class="hlt">Granular</span> Polytetrafluoroethylene Resin From Italy; Scheduling of an Expedited Five-Year Review...</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.gpo.gov/fdsys/browse/collection.action?collectionCode=FR">Federal Register 2010, 2011, 2012, 2013</a></p> <p class="result-summary">...<span class="hlt">Granular</span> Polytetrafluoroethylene Resin From Italy; Scheduling of an Expedited Five-Year...<span class="hlt">Granular</span> Polytetrafluoroethylene Resin From Italy AGENCY: United States International Trade...<span class="hlt">granular</span> polytetrafluoroethylene resin from Italy would be likely to lead to...</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">2011-05-12</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">317</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/52733064"> <span id="translatedtitle">Video Analysis of <span class="hlt">Granular</span> Gases in a Low-Gravity Environment</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary"><span class="hlt">Granular</span> Agglomeration in Non-Gravitating Systems is a research project undertaken by the University of Tulsa <span class="hlt">Granular</span> Dynamics Group. The project investigates the effects of weightlessness on <span class="hlt">granular</span> systems by studying the dynamics of a \\</p> <div class="credits"> <p class="dwt_author">Erin Lewallen</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">318</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2006APS..MAR.G7005J"> <span id="translatedtitle">Force fluctuations and shear banding near the jamming transition in <span class="hlt">granular</span> materials</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">What are the structural changes which turn an un-jammed system that flows like a liquid into a jammed, solid-like configuration or vice versa? For <span class="hlt">granular</span> just as for molecular systems it turns out that these changes are so subtle that so far there still has been no clean way of identifying the transition based on direct measurements of the grains' or molecules' spatial arrangements. However, in macroscopic <span class="hlt">granular</span> systems it is possible to measure also the forces between contacting grains. At high packing densities near jamming, where nearly all particles touch neighbors, contact force measurements pick up directly and sensitively what <span class="hlt">matters</span> most, namely changes in relative grain position. They thus can act as magnifier for even minute structural rearrangements. This talk will discuss experiments [1] able to detect a structural signature of the jamming transition by analyzing changes in the shape of the distribution of contact forces. The second part of the talk will be devoted to discussing new experimental geometries in which shear bands, usually localized to within about 10 grain diameters at the onset of shear, can become much wider. This allows for detailed studies of the shear rate profile and the associated velocity fluctuations. I will compare data we recently obtained from direct imaging by video, magnetic resonance imaging of the interior, and molecular dynamics simulations [2]. [1] E. I. Corwin, H. M. Jaeger, S. R. Nagel, “Structural signature of jamming in <span class="hlt">granular</span> media”, Nature 435, 1075 (2005). [2] X. Cheng, J. B. Lechman, A. F. Barbero, G. S. Grest, H. M. Jaeger, G. S. Karczmar, M. E. Möbius, and S. R. Nagel, “Three- dimensional shear in <span class="hlt">granular</span> flow”, cond-mat/0507469.</p> <div class="credits"> <p class="dwt_author">Jaeger, Heinrich</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-03-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">319</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2011ArRMA.199....1A"> <span id="translatedtitle">The Slow Erosion Limit in a Model of <span class="hlt">Granular</span> Flow</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We study a 2 × 2 system of balance laws that describes the evolution of a <span class="hlt">granular</span> material (avalanche) flowing downhill. The original model was proposed by Hadeler and Kuttler (Granul <span class="hlt">Matter</span> 2:9-18, 1999). The Cauchy problem for this system has been studied by the authors in recent papers (Amadori and Shen in Commun Partial Differ Equ 34:1003-1040, 2009; Shen in J Math Anal Appl 339:828-838, 2008). In this paper, we first consider an initial-boundary value problem. The boundary condition is given by the flow of the incoming material. For this problem we prove the global existence of BV solutions for a suitable class of data, with bounded but possibly large total variations. We then study the "slow erosion (or deposition) limit". We show that, if the thickness of the moving layer remains small, then the profile of the standing layer depends only on the total mass of the avalanche flowing downhill, not on the time-law describing the rate at which the material slides down. More precisely, in the limit as the thickness of the moving layer tends to zero, the slope of the mountain is provided by an entropy solution to a scalar integro-differential conservation law.</p> <div class="credits"> <p class="dwt_author">Amadori, Debora; Shen, Wen</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">320</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2008PhDT.......283L"> <span id="translatedtitle">The thermodynamics of dense <span class="hlt">granular</span> flow and jamming</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The scope of the thesis is to propose, based on experimental evidence and theoretical validation, a quantifiable connection between systems that exhibit the jamming phenomenon. When jammed, some materials that flow are able to resist deformation so that they appear solid-like on the laboratory scale. But unlike ordinary fusion, which has a critically defined criterion in pressure and temperature, jamming occurs under a wide range of conditions. These condition have been rigorously investigated but at the moment, no self-consistent framework can apply to grains, foam and colloids that may have suddenly ceased to flow. To quantify the jamming behavior, a constitutive model of dense <span class="hlt">granular</span> flows is deduced from shear-flow experiments. The empirical equations are then generalized, via a thermodynamic approach, into an equation-of-state for jamming. Notably, the unifying theory also predicts the experimental data on the behavior of molecular glassy liquids. This analogy paves a crucial road map for a unifying theoretical framework in condensed <span class="hlt">matter</span>, for example, ranging from sand to fire retardants to toothpaste.</p> <div class="credits"> <p class="dwt_author">Lu, Shih Yu</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_15");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" 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id="NextPageLink" onclick='return showDiv("page_18");' href="#" title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">321</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/21681830"> <span id="translatedtitle">Minkowski tensor shape analysis of cellular, <span class="hlt">granular</span> and porous structures.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Predicting physical properties of materials with spatially complex structures is one of the most challenging problems in material science. One key to a better understanding of such materials is the geometric characterization of their spatial structure. Minkowski tensors are tensorial shape indices that allow quantitative characterization of the anisotropy of complex materials and are particularly well suited for developing structure-property relationships for tensor-valued or orientation-dependent physical properties. They are fundamental shape indices, in some sense being the simplest generalization of the concepts of volume, surface and integral curvatures to tensor-valued quantities. Minkowski tensors are based on a solid mathematical foundation provided by integral and stochastic geometry, and are endowed with strong robustness and completeness theorems. The versatile definition of Minkowski tensors applies widely to different types of morphologies, including ordered and disordered structures. Fast linear-time algorithms are available for their computation. This article provides a practical overview of the different uses of Minkowski tensors to extract quantitative physically-relevant spatial structure information from experimental and simulated data, both in 2D and 3D. Applications are presented that quantify (a) alignment of co-polymer films by an electric field imaged by surface force microscopy; (b) local cell anisotropy of spherical bead pack models for <span class="hlt">granular</span> <span class="hlt">matter</span> and of closed-cell liquid foam models; (c) surface orientation in open-cell solid foams studied by X-ray tomography; and (d) defect densities and locations in molecular dynamics simulations of crystalline copper. PMID:21681830</p> <div class="credits"> <p class="dwt_author">Schröder-Turk, G E; Mickel, W; Kapfer, S C; Klatt, M A; Schaller, F M; Hoffmann, M J F; Kleppmann, N; Armstrong, P; Inayat, A; Hug, D; Reichelsdorfer, M; Peukert, W; Schwieger, W; Mecke, K</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-06-17</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">322</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013AIPC.1542..341Y"> <span id="translatedtitle">The theory of <span class="hlt">granular</span> packings for coarse soils</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Coarse soils are substances made of grains of different shape, size and orientation. In this paper, new massive-measurable grain indexes are defined to develop a simple and systematic theory for the ideal packing of grains. First, a linear relationship between an assemblage of monodisperse spheres and an assemblage of polydisperse grains is deduced. Then, a general formula for the porosity of linearly ordered packings of spheres in contact is settled down by the appropriated choosing of eight neighboring spheres located at the vertices of the unit parallelepiped. The porosity of axisymmetric packings of grains, related to sand piles and axisymmetric compression tests, is proposed to be determined averaging the respective linear parameters. Since they can be tested experimentally, porosities of the densest state and the loosest state of a <span class="hlt">granular</span> soil can be used to verify the accuracy of the present theory. Diagrams for these extreme quantities show a good agreement between the theoretical lines and the experimental data, no <span class="hlt">matter</span> the dependency on the protocols and mineral composition.</p> <div class="credits"> <p class="dwt_author">Yanqui, Calixtro</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-06-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">323</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/3708443"> <span id="translatedtitle">Predominant bacterial genera in <span class="hlt">granular</span> activated carbon water treatment systems.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary"><span class="hlt">Granular</span> activated carbon (GAC) beds may be used for removal of dissolved organic <span class="hlt">matter</span> during the treatment of drinking water. However, they might also change the microbiological quality of the water entering the distribution system either by changing the predominant bacteria or the bacterial density of the treated water. A 3-year pilot plant study of water treatment using GAC beds was conducted at the Baxter Water Treatment Plant in Philadelphia. During the study, bacteria were isolated from the raw water and from the effluents of the GAC treatment units. At the end of the study, bacteria were also isolated from the GAC units and from sand beds operated in parallel with the GAC units. Bacterial genera in the GAC effluents and in the GAC units themselves were similar to those found in the raw water and in the sand beds. Prechlorination and (or) preozonation of the water before GAC treatment had no noticeable effect on the bacterial genera found as compared with GAC unit having no predisinfection. The bacterial genera found in this study were similar to those found in seven other studies of GAC water treatment that used a variety of treatment schemes and a variety of heterotrophic plate count techniques to evaluate bacterial populations. From these several studies it appears that GAC treatment does not change the nature of the bacterial populations associated with drinking water. PMID:3708443</p> <div class="credits"> <p class="dwt_author">Burlingame, G A; Suffet, I H; Pipes, W O</p> <p class="dwt_publisher"></p> <p class="publishDate">1986-03-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">324</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012APS..MARD53003J"> <span id="translatedtitle">Elastic weakening of a dense <span class="hlt">granular</span> medium by acoustic fluidization</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Elastic waves propagating through a dense <span class="hlt">granular</span> pack provide a unique probe of the elastic properties and internal dissipation of the medium [1], and also allow investigating the irreversible rearrangement of the contact network at large vibration amplitude. In this talk, we describe two distinct types of nonlinearity, i.e. hertzian and frictional, at the grain contact by sound amplitude and velocity measurements, respectively, under different confining pressure [2]. Beyond certain wave amplitude, the sound-<span class="hlt">matter</span> interaction becomes irreversible, leaving the medium in a weakened and slightly compacted state. A slow recovery of the initial elastic modulus is observed after acoustic perturbation, revealing the plastic creep growth of microcontacts. The cross-correlation function of configuration-specific acoustic speckles highlights the relationship between the macroscopic elastic weakening and the local change of the contact networks, induced by strong sound vibration, in the absence of appreciable grain motion. We show that the softening of elastic modulus is much more pronounced with the shear wave (up to 20%) than with the compressional wave (to 10%). [4pt] [1] Th. Brunet, X. Jia and P. Mills, Phys. Rev. Lett 101, 138001 (2008) [0pt] [2] Th. Brunet, X. Jia and P. Johnson, Geophys. Res. Lett 35, L19308 (2008); X. Jia, Th. Brunet and J. Laurent, Phys. Rev. E 00, 000300(R) (2011)</p> <div class="credits"> <p class="dwt_author">Jia, Xiaoping; Laurent, Jerome; Wildenberg, Siet; van Hecke, Martin</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-02-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">325</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2011APS..DFDH29003D"> <span id="translatedtitle"><span class="hlt">Wetting</span> dynamics of living drops</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Tissue spreading is a fundamental process in embryonic development, wound healing, and cancer invasion. We study the spreading dynamics of cell aggregates on solid substrates by means of an analogy with the <span class="hlt">wetting</span> of a viscoelastic drop. At long times, a precursor film of cells spreads around the aggregate with two possible states: either a liquid state (cohesive migration) or a 2D gas state (where cells escape individually) depending on the cell-cell adhesion. These results provide insight into the progression of a non-invasive tumor into a metastatic malignant carcinoma.</p> <div class="credits"> <p class="dwt_author">Douezan, Stephane; Guevorkian, Karine; Dufour, Sylvie; Cuvelier, Damien; Brochard-Wyart, Francoise</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-11-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">326</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/6350428"> <span id="translatedtitle"><span class="hlt">Wet</span> coastal plain tundra III</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">This year's census data for the <span class="hlt">wet</span> coastal plain tundra in Alaska; North Slope Borough, 3 km SSE of Naval Arctic Research Laboratory, Barrow; 71/sup 0/ 18'N, 156/sup 0/ 38'W; Barrow Quadrangle, USGS reflect a decrease in the total number of species breeding. However, total breeding density rose by 82%. Lapland Longspurs (up 105%) accounted for half of this increase while the rest was spread among many species. There was a total of 8 species; 40.5 territorial males or females (162/km/sup 2/, 66/100 acres).</p> <div class="credits"> <p class="dwt_author">Myers, J.P.; Gellman, S.T.; Pitelka, F.A.</p> <p class="dwt_publisher"></p> <p class="publishDate">1980-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">327</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2009AIPC.1145..223F"> <span id="translatedtitle">Image Segmentation Techniques for <span class="hlt">Granular</span> Materials</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">To improve understanding of the mechanical behavior of <span class="hlt">granular</span> materials it is important to be able to quantify the relative arrangement of the grains, i.e. the fabric. This can be done, for example, by measuring the orientations of the particles (e.g. the long axis orientation) or by considering the orientations of the vectors normal to each grain-grain contact. In two dimensional (2D) analyses this information can be obtained by digital image analysis of images of thin sections obtained from an optical microscope. While such data is useful, <span class="hlt">granular</span> materials of engineering interest are three dimensional (3D) materials and quantification of the 3D fabric is necessary. Micro Computed-Tomography (?CT) together with 3D image analysis has emerged as a promising technique for obtaining the 3D data required. This paper aims to highlight the challenges associated with using image analysis to provide quantitative information on fabric. While automated image segmentation has proved to produce reasonable results in some cases, it is sometimes less successful when dealing with highly irregular and angular soil grains. This paper evaluates the effectiveness of 2D and 3D segmentation techniques that rely on the watershed segmentation algorithm. The primary material considered is Reigate Silver Sand, a natural quartzitic sand with grain diameters in the range of 150-300 ?m. While the sand considered is primarily of interest to geotechnical engineers, the results of this study will be of interest to anyone seeking to quantify <span class="hlt">granular</span> material fabric using either 2D microscopy data or ?CT 3D data sets.</p> <div class="credits"> <p class="dwt_author">Fonseca, J.; O'Sullivan, C.; Coop, M. R.</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-06-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">328</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/41154638"> <span id="translatedtitle">Geomorphology, disturbance, and the soil and vegetation of two subtropical <span class="hlt">wet</span> steepland watersheds of Puerto Rico</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Relationships between landforms, soil nutrients, forest structure, and the relative importance of different disturbances were quantified in two subtropical <span class="hlt">wet</span> steepland watersheds in Puerto Rico. Ridges had fewer landslides and treefall gaps, more above-ground biomass, older aged stands, and greater species richness than other landscape positions. Ridge soils had relatively low quantities of exchangeable bases but high soil organic <span class="hlt">matter</span>,</p> <div class="credits"> <p class="dwt_author">F. N. Scatena; Ariel E. Lugo</p> <p class="dwt_publisher"></p> <p class="publishDate">1995-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">329</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/22803471"> <span id="translatedtitle">[Dynamic changes of soil amino sugar contents under drying and <span class="hlt">wetting</span> cycle].</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">A soil incubation test was conducted to study the quantitative changes of three amino sugars (glucosamine, muramic acid, and galactosamine) derived from microbes under drying and <span class="hlt">wetting</span> cycle, and to analyze the relative contribution of soil bacteria and fungi to the turnover of soil organic <span class="hlt">matter</span> by using the measured glucosamine/muramic acid ratio. Under continuous <span class="hlt">wetting</span>, the degradation of bacteria-derived muramic acid was faster than that of fungi-derived glucosamine, and the degradation rate of galactosamine was the lowest. Drying and <span class="hlt">wetting</span> cycle altered the degradation characteristics of the three amino sugars. As compared with that under continuous <span class="hlt">wetting</span>, the degradation rate of bacteria-derived muramic acid at the prophase of drying and <span class="hlt">wetting</span> was faster than that of fungi-derived glucosamine, and, with the increasing frequency of drying and <span class="hlt">wetting</span> cycle, the degradation rate of fungi-derived glucosamine was faster than that of bacteria-derived muramic acid. These results indicated that drying and <span class="hlt">wetting</span> cycle changed the course of the microbial transformation of soil amino sugar-derived nitrogen. PMID:22803471</p> <div class="credits"> <p class="dwt_author">Zhang, Wei; Han, Yong-Jiao; He, Hong-Bo; Xie, Hong-Tu; Zhang, Xu-Dong</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-04-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">330</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2008APS..MAR.D7005G"> <span id="translatedtitle">Biological and robotic movement through <span class="hlt">granular</span> media</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We discuss laboratory experiments and numerical simulations of locomotion of biological organisms and robots on and within a <span class="hlt">granular</span> medium. Terrestrial locomotion on <span class="hlt">granular</span> media (like desert and beach sand) is unlike locomotion on rigid ground because during a step the material begins as a solid, becomes a fluid and then re-solidifies. Subsurface locomotion within <span class="hlt">granular</span> media is unlike swimming in water for similar reasons. The fluidization and solidification depend on the packing properties of the material and can affect limb penetration depth and propulsive force. Unlike aerial and aquatic locomotion in which the Navier-Stokes equations can be used to model environment interaction, models for limb interaction with <span class="hlt">granular</span> media do not yet exist. To study how the fluidizing properties affect speed in rapidly running and swimming lizards and crabs, we use a trackway composed of a fluidized bed of of 250 ?m glass spheres. Pulses of air to the bed set the solid volume fraction 0.59<?<0.63; a constant flow rate Q below the onset of fluidization (at Q=Qf) linearly reduces the material strength (resistance force per depth) at fixed ? for increasing Q. Systematic studies of four species of lizard and a species of crab (masses 20 grams) reveal that as Q increases, the average running speed of an animal decreases proportionally to ?M/A-const(1-Q/Qf) where M is the mass of the animal and A is a characteristic foot area. While the crabs decrease speed by nearly 75 % as the material weakens to a fluid, the zebra tailed lizard uses long toes and a plantigrade foot posture at foot impact to maintain high speed ( 1.5 m/sec). We compare our biological results to systematic studies of a physical model of an organism, a 2 kg hexapedal robot SandBot. We find that the robot speed sensitively depends on ? and the details of the limb trajectory. We simulate the robot locomotion by computing ground reaction forces on a numerical model of the robot using a soft-sphere Molecular Dynamics code.</p> <div class="credits"> <p class="dwt_author">Goldman, Daniel</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-03-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">331</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/1995Sci...267.1632E"> <span id="translatedtitle"><span class="hlt">Granular</span> convection observed by magnetic resonance imaging</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Vibrations in a <span class="hlt">granular</span> material can spontaneously produce convection rolls reminiscent of those seen in fluids. Magnetic resonance imaging provides a sensitive and noninvasive probe for the detection of these convection currents, which have otherwise been difficult to observe. A magnetic resonance imaging study of convection in a column of poppy seeds yielded data about the detailed shape of the convection rolls and the depth dependence of the convection velocity. The velocity was found to decrease exponentially with depth; a simple model for this behavior is presented here.</p> <div class="credits"> <p class="dwt_author">Ehrichs, E. E.; Jaeger, H. M.; Karczmar, Greg S.; Knight, James B.; Kuperman, Vadim Yu.; Nagel, Sidney R.</p> <p class="dwt_publisher"></p> <p class="publishDate">1995-03-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">332</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2004PhRvE..70f0301H"> <span id="translatedtitle">Mach cone in a shallow <span class="hlt">granular</span> fluid</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We study the V -shaped wake (Mach cone) formed by a cylindrical rod moving through a thin, vertically vibrated <span class="hlt">granular</span> layer. The wake, analogous to a shock (hydraulic jump) in shallow water, appears for rod velocities vR greater than a critical velocity c . We measure the half angle ? of the wake as a function of vR and layer depth h . The angle satisfies the Mach relation, sin?=c/vR , where c=gh , even for h as small as one-particle diameter.</p> <div class="credits"> <p class="dwt_author">Heil, Patrick; Rericha, E. C.; Goldman, Daniel I.; Swinney, Harry L.</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">333</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013AIPC.1542..385J"> <span id="translatedtitle"><span class="hlt">Granular</span> jamming transitions for a robotic mechanism</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The jamming transitions for granules growing field of interest in robotics for use in variable stiffness mechanisms. However, the traditional use of air pressure to control the jamming transition requires heavy vacuums, reducing the mobility of the robot. Thus, we propose the use of water as a hydraulic fluid to control the transition between free and clustered granules. This paper presents comparative studies that show that a hydraulic <span class="hlt">granular</span> jammed finger joint can both achieve the same stiffness level and maintain the same hysteresis level of a pneumatic system, with only a small volume of fluid.</p> <div class="credits"> <p class="dwt_author">Jiang, Allen; Aste, Tomaso; Dasgupta, Prokar; Althoefer, Kaspar; Nanayakkara, Thrishantha</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-06-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">334</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013AIPC.1542..337H"> <span id="translatedtitle">DEM simulation of experimental dense <span class="hlt">granular</span> packing</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">In this study we present numerical analysis performed on the experimental results of sphere packings of mono-sized hard sphere whose packing fraction spans across a wide range of 0.59<?<0.72. Using X-ray Computed Tomography (XCT), we have full access to the 3D structure of the <span class="hlt">granular</span> packings. Numerical analysis performed on thr data provides the first experimental proofs of how densification affects local order parameters. Furthermore by combining Discrete Element Method (DEM) and the experimental results from XCT, we investigate how the intergranular forces change with the onset of crystallization.</p> <div class="credits"> <p class="dwt_author">Hanifpour, Maryam; Francois, Nicolas; Allaei, Mehdi Vaez; Saadatfar, Mohammad</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-06-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">335</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/759978"> <span id="translatedtitle">Simulation of <span class="hlt">Granular</span> Compacts in Two Dimensions</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Simulations of <span class="hlt">granular</span> packings in 2-D by throwing disks in a rectangular die are performed. Different size distributions as bimodal, uniform and gaussian are used. Once the array of particles is done, a relaxation process is carried on using a large-amplitude, low-frequency vertical shaking. This relaxation is performed a number N of times. Then, the authors measure the density of the package, contact distribution, coordination number distribution, entropy and also the disks size distribution vs. height. The dependence of all these magnitudes on the number N of shakings used to relax the packing and on the size distribution parameters are explored and discussed.</p> <div class="credits"> <p class="dwt_author">VIDALES,A.M.; KENKRE,V.M.; HURD,ALAN J.</p> <p class="dwt_publisher"></p> <p class="publishDate">2000-07-24</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">336</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/19391789"> <span id="translatedtitle">Rolling friction on a <span class="hlt">granular</span> medium.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">We present experimental results for the rolling of spheres on a <span class="hlt">granular</span> bed. We use two sets of glass and steel spheres with varying diameters and a high-speed camera to follow the motion of the spheres. Despite the complex phenomena occurring during the rolling, the results show a friction coefficient nearly independent of the velocity (0.45-0.5 for glass and 0.6-0.65 for steel). It is found that for a given sphere density, the large spheres reach a longer distance, a result that may also help explain the rock sorting along natural stone accumulations at the foot of mountain slopes. PMID:19391789</p> <div class="credits"> <p class="dwt_author">De Blasio, Fabio Vittorio; Saeter, May-Britt</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-02-12</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">337</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013APS..MAR.Z2004D"> <span id="translatedtitle">Dilatancy and Diffusion in Sheared <span class="hlt">Granular</span> Materials</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Disordered materials such as sand, foams and emulsions display a wide variety of different forms of mechanical behavior. Currently the origin of this rich dynamics is the subject of intense study. Experimentally it has proved difficult to probe the microscopic dynamics in these systems. We present an overview of experimental investigations that have been successful in giving more insight into the microstructural dynamics of disordered systems. We focus on shear induced dilatancy and diffusion in quasi statically deformed <span class="hlt">granular</span> materials and suspensions and contrast the behavior of low and high friction particulate materials. We shall discuss the consequences of our observations in the context of shear banding and jamming phenomena.</p> <div class="credits"> <p class="dwt_author">Dijksman, Joshua</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-03-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">338</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/10991519"> <span id="translatedtitle">Thermal convection in fluidized <span class="hlt">granular</span> systems</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Thermal convection is observed in molecular dynamic simulations of a fluidized <span class="hlt">granular</span> system of nearly elastic hard disks moving under gravity, inside a square box. Boundaries introduce no shearing or time dependence, but the energy injection comes from a slip (shear-free) thermalizing base. The top wall is perfectly elastic and lateral boundaries are either elastic or periodic. The spontaneous temperature gradient appearing in the system due to the inelastic collisions, combined with gravity, produces a buoyancy force that, when dissipation is large enough, triggers convection. PMID:10991519</p> <div class="credits"> <p class="dwt_author">Ramirez; Risso; Cordero</p> <p class="dwt_publisher"></p> <p class="publishDate">2000-08-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">339</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/19391932"> <span id="translatedtitle">Effective boundary conditions for dense <span class="hlt">granular</span> flows.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">We derive an effective boundary condition for dense <span class="hlt">granular</span> flow taking into account the effect of the heterogeneity of the force network on sliding friction dynamics. This yields an intermediate boundary condition which lies in the limit between no slip and Coulomb friction; two simple functions relating wall stress, velocity, and velocity variance are found from numerical simulations. Moreover, we show that this effective boundary condition corresponds to Navier slip condition when the model of G. D. R. Midi [Eur. Phys. J. E 14, 341 (2004)] is assumed to be valid, and that the slip length depends on the length scale that characterizes the system, viz. the particle diameter. PMID:19391932</p> <div class="credits"> <p class="dwt_author">Artoni, Riccardo; Santomaso, Andrea; Canu, Paolo</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-03-23</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">340</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/753412"> <span id="translatedtitle">Gravity-driven dense <span class="hlt">granular</span> flows</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">The authors report and analyze the results of numerical studies of dense <span class="hlt">granular</span> flows in two and three dimensions, using both linear damped springs and Hertzian force laws between particles. Chute flow generically produces a constant density profile that satisfies scaling relations suggestive of a Bagnold grain inertia regime. The type for force law has little impact on the behavior of the system. Failure is not initiated at the surface, consistent with the absence of surface flows and different principal stress directions at vs. below the surface.</p> <div class="credits"> <p class="dwt_author">ERTAS,DENIZ; GREST,GARY S.; HALSEY,THOMAS C.; DEVINE,DOV; SILBERT,LEONARDO E.</p> <p class="dwt_publisher"></p> <p class="publishDate">2000-03-29</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_16");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" 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showDiv("page_25");' href="#">25</a> </span> </span> <a id="NextPageLink" onclick='return showDiv("page_19");' href="#" title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">341</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013EPJC...73.2491J"> <span id="translatedtitle">Special relativity induced by <span class="hlt">granular</span> space</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We show that the special relativistic dynamics, when combined with quantum mechanics and the concept of superstatistics, can be interpreted as arising from two interlocked non-relativistic stochastic processes that operate at different energy scales. This framework leads to Feynman amplitudes that are, in the Euclidean regime, identical to the transition probability of a Brownian particle propagating through a <span class="hlt">granular</span> space. For illustration we consider the dynamics and the propagator of a Klein-Gordon particle. Implications for deformed special relativity, quantum field theory, quantum gravity and cosmology are also discussed.</p> <div class="credits"> <p class="dwt_author">Jizba, Petr; Scardigli, Fabio</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-07-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">342</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www2.msm.ctw.utwente.nl/sluding/PAPERS/alam_pg2005.pdf"> <span id="translatedtitle">Non-Newtonian <span class="hlt">Granular</span> Fluids: Simulation and Theory</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Rheological properties of <span class="hlt">granular</span> fluids are probed via event-driven simulations of the inelastic hard-sphere model. We find that <span class="hlt">granular</span> fluids support large normal stress differences for the whole range of densities, clearly indicating their non-Newtonian rheology. Interestingly, both first ( ) and second ( ) normal stress differences undergo sign-reversals with density. While changes its sign in the dense limit,</p> <div class="credits"> <p class="dwt_author">M. Alam; S. Luding</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">343</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/23610458"> <span id="translatedtitle"><span class="hlt">Granular</span> Cell Ameloblastoma: Enigmatic Cells in an Unusual Neoplasm.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">An unusual <span class="hlt">granular</span> variant of ameloblastoma presenting as a mandibular mass in a 43-year-old woman is described. These visually striking tumors display unusual and inconsistent immunohistochemical staining patterns although differential diagnosis from other <span class="hlt">granular</span> cell lesions of the head and neck is usually not problematic. PMID:23610458</p> <div class="credits"> <p class="dwt_author">Sharma, Prashant; Nigam, Sonu; Agarwal, Arun Kumar</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-04-22</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">344</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/48953845"> <span id="translatedtitle">Experimental study of bedrock erosion by <span class="hlt">granular</span> flows</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Field studies suggest that bedrock incision by <span class="hlt">granular</span> flows may be the primary process cutting valleys in steep, unglaciated landscapes. An expression has been proposed for debris flow incision into bedrock which posits that erosion rate depends on stresses due to <span class="hlt">granular</span> interactions at the snout of debris flows. Here, we explore this idea by conducting laboratory experiments to test</p> <div class="credits"> <p class="dwt_author">Leslie Hsu; William E. Dietrich; Leonard S. Sklar</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">345</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/12741168"> <span id="translatedtitle">Simple model for reverse buoyancy in a vibrated <span class="hlt">granular</span> system</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">We report an experimental study of the motion of a large sphere immersed in a deep dry <span class="hlt">granular</span> bed, subjected to vertical sinusoidal vibrations. Under certain conditions large heavy objects immersed in a homogeneous vibrated <span class="hlt">granular</span> medium rise and similar light ones sink to the bottom. This is called reverse buoyancy. We have measured the vertical velocity of immersed large</p> <div class="credits"> <p class="dwt_author">G. Gutiérrez; O. Pozo; L. I. Reyes; R. Paredes V; J. F. Drake; E. Ott</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">346</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/50688461"> <span id="translatedtitle">Duductive data analysis and mining <span class="hlt">Granular</span> Computing on relation data</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">This article is about the data analysis and mining aspects of <span class="hlt">granular</span> computing (GrC) that includes rough set theory (RST). This subject involves four concepts, deductive data analysis and mining (DDAM), relational databases (RDB), rough set theory (RST) and the <span class="hlt">granular</span> computing (GrC). The results are quite far reaching.</p> <div class="credits"> <p class="dwt_author">Tsau Young Lin</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">347</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/50778630"> <span id="translatedtitle">Threshold image segmentation based on <span class="hlt">granular</span> immune algorithm</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Image segmentation is an important processing step in many image, video and computer vision applications. Artificial Immune Systems (AIS) is a diverse area of research that attempts to bridge the divide between immunological and engineering. In this paper, we present a threshold method based on <span class="hlt">granular</span> immune algorithm (GIA) for image segmentation, which includes <span class="hlt">granular</span> hierarchy and immunological mechanism. Based</p> <div class="credits"> <p class="dwt_author">Xu Xinying; Zhang Zhijun; Xie Jun; Xie Keming</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">348</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://oaspub.epa.gov/eims/eimsapi.dispdetail?deid=104755"> <span id="translatedtitle">USE OF <span class="hlt">GRANULAR</span> GRAPHITE FOR ELECTROLYTIC DECHLORINATION OF TRICHLOROETHYLENE</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p class="result-summary"><span class="hlt">Granular</span> graphite is a potential electrode material for the electrochemical remediation of refractory chlorinated organic compounds such as trichloroethylene (TCE). However, the use of <span class="hlt">granular</span> graphite can complicate the experimental results. On one hand, up to 99% of TCE was re...</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">349</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/5554410"> <span id="translatedtitle">A network model of geometrically constrained deformations of <span class="hlt">granular</span> materials</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Abstract. We study quasi-static deformation of dense <span class="hlt">granular</span> packings. In the reference configuration, a <span class="hlt">granular</span> material is under confining stress (pre- stress). Then the packing is deformed by imposing external boundary condi- tions, which model engineering experiments such as shear and compression. The deformation is assumed,to preserve the local structure of neighbors for each particle, which is a realistic assumption</p> <div class="credits"> <p class="dwt_author">K. A. Ariyawansa; Leonid Berlyand; Alexander Panchenko</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">350</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/10161409"> <span id="translatedtitle">Flow and jamming of <span class="hlt">granular</span> mixtures through obstacles</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Due to the formation of arches, <span class="hlt">granular</span> materials may jam when flowing through obstacles, as in the case of hoppers. As a way to quantify this process, we study experimentally the flow of binary <span class="hlt">granular</span> mixtures through sieves, as a function of two parameters: the proportion of large grains and the ratio of large grains to sieve hole size. We</p> <div class="credits"> <p class="dwt_author">F. Chevoir; F. Gaulard; N. Roussel</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">351</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/55590922"> <span id="translatedtitle">Lie group symmetry analysis for <span class="hlt">granular</span> media stress equations</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The Airy stress function, although frequently employed in classical linear elasticity, does not receive similar usage for <span class="hlt">granular</span> media problems. For plane strain quasi-static deformations of a cohesionless Coulomb-Mohr <span class="hlt">granular</span> solid, a single nonlinear partial differential equation is formulated for the Airy stress function by combining the equilibrium equations with the yield condition. This has certain advantages from the usual</p> <div class="credits"> <p class="dwt_author">I. Kenneth Johnpillai; Scott W. McCue; James M. Hill</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">352</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/16224194"> <span id="translatedtitle">Lie group symmetry analysis for <span class="hlt">granular</span> media stress equations</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The Airy stress function, although frequently employed in classical linear elasticity, does not receive similar usage for <span class="hlt">granular</span> media problems. For plane strain quasi-static deformations of a cohesionless Coulomb–Mohr <span class="hlt">granular</span> solid, a single nonlinear partial differential equation is formulated for the Airy stress function by combining the equilibrium equations with the yield condition. This has certain advantages from the usual</p> <div class="credits"> <p class="dwt_author">I. Kenneth Johnpillai; Scott W. McCue; James M. Hill</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">353</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://oaspub.epa.gov/eims/eimsapi.dispdetail?deid=39503"> <span id="translatedtitle">BACTERIA ASSOCIATED WITH <span class="hlt">GRANULAR</span> ACTIVATED CARBON PARTICLES IN DRINKING WATER</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p class="result-summary">A sampling protocol was developed to examine particles released from <span class="hlt">granular</span> activated carbon filter beds. A gauze filter/Swinnex procedure was used to collect carbon fines from 201 <span class="hlt">granular</span> activated carbon-treated drinking water samples over 12 months. Application of a homogen...</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">354</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/51052129"> <span id="translatedtitle">Hydrothermal Modification of <span class="hlt">Granular</span> Steel Slag for Phosphate Removal</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The performance of phosphate removal using hydrothermal modified <span class="hlt">granular</span> steel slag was evaluated. The effects of steel slag dosage, reaction time, solution pH and initial phosphate concentration of synthesized wastewater on phosphate removal were also investigated. The results show that the modified steel slag is more efficient than raw <span class="hlt">granular</span> steel slag in phosphate removal. The residual phosphate concentration decreased</p> <div class="credits"> <p class="dwt_author">Guangwei Wang; Liping Qiu; Shoubin Zhang; Xuedong Zhai; Jun Ma</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">355</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/52908917"> <span id="translatedtitle">Hysteresis in a hydrodynamic model of dense <span class="hlt">granular</span> flows</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">A hydrodynamic model for dense <span class="hlt">granular</span> flows, previously developed for confined flows, has been extended to address free surface flow down an inclined chute. Results show that the model can predict the existence of two critical inclination angles, namely, the avalanche starting angle thetastart above which the <span class="hlt">granular</span> bed begins flowing from an initially jammed configuration, and an avalanche stopping</p> <div class="credits"> <p class="dwt_author">Riccardo Artoni; Andrea Santomaso; Paolo Canu</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">356</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.springerlink.com/index/m8247q0754524726.pdf"> <span id="translatedtitle">Common bile duct obstruction by <span class="hlt">granular</span> cell tumor (Schwannoma)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Summary A patient with <span class="hlt">granular</span> cell tumor causing intermittent obstruction of the common bile duct was found for the first time in a male. Surgical management of these lesions includes excision of the tumor, cholecystectomy, and choledochoduodenostomy. A syndrome of intermittent obstructive jaundice without preceding gallbladder symptoms in a young black individual should make one suspect <span class="hlt">granular</span> cell tumor obstructing</p> <div class="credits"> <p class="dwt_author">Joseph D. Whisnant; Shelley E. Bennett; Stanley R. Huffman; Daniel L. Weiss; Joseph C. Parker; Ward O. Griffen</p> <p class="dwt_publisher"></p> <p class="publishDate">1974-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">357</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/50863971"> <span id="translatedtitle">Ultrasonic characterization of unconsolidated <span class="hlt">granular</span> media undergoing compaction</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">In this work we present a method using ultrasonic waves to probe accurately the elasticity of a 3-D <span class="hlt">granular</span> packing, where other existing methods fail (optical for instance). In order to reach a large number of different mechanical states of the disordered <span class="hlt">granular</span> structure, we use the well-known compaction process. The objective is to understand the influence of parameters like</p> <div class="credits"> <p class="dwt_author">Jean-Baptiste Legland; Vincent Tournat; Vitalyi Gusev</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">358</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/875609"> <span id="translatedtitle">Elucidating the mysteries of <span class="hlt">wetting</span>.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Nearly every manufacturing and many technologies central to Sandia's business involve physical processes controlled by interfacial <span class="hlt">wetting</span>. Interfacial forces, e.g. conjoining/disjoining pressure, electrostatics, and capillary condensation, are ubiquitous and can surpass and even dominate bulk inertial or viscous effects on a continuum level. Moreover, the statics and dynamics of three-phase contact lines exhibit a wide range of complex behavior, such as contact angle hysteresis due to surface roughness, surface reaction, or compositional heterogeneities. These thermodynamically and kinetically driven interactions are essential to the development of new materials and processes. A detailed understanding was developed for the factors controlling wettability in multicomponent systems from computational modeling tools, and experimental diagnostics for systems, and processes dominated by interfacial effects. Wettability probed by dynamic advancing and receding contact angle measurements, ellipsometry, and direct determination of the capillary and disjoining forces. Molecular scale experiments determined the relationships between the fundamental interactions between molecular species and with the substrate. Atomistic simulations studied the equilibrium concentration profiles near the solid and vapor interfaces and tested the basic assumptions used in the continuum approaches. These simulations provide guidance in developing constitutive equations, which more accurately take into account the effects of surface induced phase separation and concentration gradients near the three-phase contact line. The development of these accurate models for dynamic multicomponent <span class="hlt">wetting</span> allows improvement in science based engineering of manufacturing processes previously developed through costly trial and error by varying material formulation and geometry modification.</p> <div class="credits"> <p class="dwt_author">Webb, Edmund Blackburn, III (,; ); Bourdon, Christopher Jay; Grillet, Anne Mary; Sackinger, Philip A.; Grest, Gary Stephen; Emerson, John Allen; Ash, Benjamin Jesse; Heine, David R.; Brooks, Carlton, F.; Gorby, Allen D.</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-11-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">359</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/379657"> <span id="translatedtitle">This technology is all <span class="hlt">wet</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">The <span class="hlt">wet</span> oxidation technology developed by Conor Pacific Environmental Technologies Inc. (CPET; Vancouver, British Columbia) is designed to eliminate hazardous and nonhazardous organic contaminants from liquid effluent. The technology, which originated in Denmark, uses oxygen homogeneously dissolved in water to treat organic contaminants. According to the company, the process eliminates hazardous and nonhazardous contaminants without generating pollutant emissions, making it relatively easy to permit. CPET says <span class="hlt">wet</span> oxidation eliminates some inorganic compounds, such as cyanides, and all hazardous and nonhazardous organic pollutants, including those found in petroleum products, aromatic solvents, tar compounds, pesticides and plasticizers. The process also handles relatively high concentrations of such contaminants as phenol, oil, and coal, tar and wood preservatives. The technology can achieve up to 99.9999% destruction efficiencies. The process is exothermic, generating its own heat, and allows energy to be recovered and recycled. Some heating is required at start-up, and heat exchangers are used to overcome heat build-up later in the process.</p> <div class="credits"> <p class="dwt_author">NONE</p> <p class="dwt_publisher"></p> <p class="publishDate">1996-09-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">360</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2010ects.book.....O"> <span id="translatedtitle">Experimental and Computational Techniques in Soft Condensed <span class="hlt">Matter</span> Physics</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">1. Microscopy of soft materials Eric R. Weeks; 2. Computational methods to study jammed Systems Carl F. Schrek and Corey S. O'Hern; 3. Soft random solids: particulate gels, compressed emulsions and hybrid materials Anthony D. Dinsmore; 4. Langmuir monolayers Michael Dennin; 5. Computer modeling of <span class="hlt">granular</span> rheology Leonardo E. Silbert; 6. Rheological and microrheological measurements of soft condensed <span class="hlt">matter</span> John R. de Bruyn and Felix K. Oppong; 7. Particle-based measurement techniques for soft <span class="hlt">matter</span> Nicholas T. Ouellette; 8. Cellular automata models of <span class="hlt">granular</span> flow G. William Baxter; 9. Photoelastic materials Brian Utter; 10. Image acquisition and analysis in soft condensed <span class="hlt">matter</span> Jeffrey S. Olafsen; 11. Structure and patterns in bacterial colonies Nicholas C. Darnton.</p> <div class="credits"> <p class="dwt_author">Olafsen, Jeffrey</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-09-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_17");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a onClick='return 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src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">361</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/6020663"> <span id="translatedtitle">Testing and verification of <span class="hlt">granular</span> filters for removal of particulate and alkalies. Final report</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">This report describes the testing and evaluation of a shallow bed <span class="hlt">granular</span> filter (GBF) concept for Pressurized, Fluidized Bed Combustion (PFBC) application. The GBF is a device on which the dustladen gas passes through a shallow bed of <span class="hlt">granular</span> media, depositing the particulate <span class="hlt">matter</span> on the surface of the bed forming a dust cake. The bed media is cleaned by a reverse flush that gently fluidizes the bed and elutriates the collected particulate <span class="hlt">matter</span> from the system. A 500 acfm subpilot scale GBF was built and tested at simulated PFBC operating conditions. Two different GBF configurations have been evaluated accounting for over 220 hours of testing (cumulative) and 615 cleaning cycles. Test variables have included bed media, filter flow face velocity, backflush conditions and dust loading. In addition to the subpilot scale test work, a modified single bed, bench scale GBF unit was evaluated as an improved design approach for PFBC conditions. Results of this work showed that the overall performance of the GBF can be improved if the system can be cleaned without fluidizing the bed media. This has resulted in redefining backflush conditions and the choice of bed media. The possibility of utilizing the GBF to remove both particulate and alkali has also been explored. Implementing an alkali gettering media as part of the GBF bed media would be possible but would require significantly deeper beds than anticipated in the current shallow bed, GBF concept. 27 references, 135 figures, 40 tables.</p> <div class="credits"> <p class="dwt_author">Not Available</p> <p class="dwt_publisher"></p> <p class="publishDate">1984-04-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">362</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013AIPC.1542..609S"> <span id="translatedtitle">Modeling of compressible self-organized <span class="hlt">granular</span> media under static load</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">A simple continual model of <span class="hlt">granular</span> medium, based on original hypotheses, is built. It describes the <span class="hlt">matter</span> under active quasi-static compression with taking into account the effects of both compaction and self-organization. The analysis of the hypotheses has given the model's constitutive relations. Thus, an exponential dependence for the porosity from the average stress and a linear relationship between the principal stresses are set. The analysis of the constitutive relations at the same time has given need for existence of two new constants. One of them characterizes particular material's compliance to compaction, its value should be determined from experiment. The other new constant is a macroscopic characteristic of the <span class="hlt">matter</span>'s mesoscopic state, its range of values has been determined and ensures for the internal consistency of the model as well as the accord with the mechanics general laws. Such applied questions as compacting <span class="hlt">granular</span> media under their own weight and the Lamé problem for them are solved in the elementary functions. The proposed Lamé problem's solution eliminates singularity at the origin. The derived theoretical predictions are in good agreement with available experimental data. The latter include data on a natural carbonates deposit at depth up to 5.5 km, snow drifts at depth up to 10 m, and nano-sized powders in capsules of 10 mm radius under the GPa order pressure.</p> <div class="credits"> <p class="dwt_author">Skachkov, Mikhail N.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-06-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">363</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/21882562"> <span id="translatedtitle">Comparison of two online flocculation monitoring techniques for predicting turbidity removal by <span class="hlt">granular</span> media filtration.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Particulate <span class="hlt">matter</span> removal in drinking water treatment via direct <span class="hlt">granular</span> filtration requires specific flocculation conditions (a process typically termed 'high energy flocculation'). Predicting filtered water turbidity based on flocculated water characteristics remains difficult. This study has sought to establish a relationship between filtered water turbidity and the flocculated water characteristics. Flocculation oflow-turbidity raw water was evaluated online using a Photometric Dispersion Analyser (PDA) and a Dynamic Particle Analyser in a modified jar test followed by a bench-scale anthracite filter. Coagulants used were alum, PASS100 and ferric sulphate, in addition to a polydiallyldimethylammonium chloride (polyDADMAC) cationic polymer. They were dosed in warm and cold waters, and flocculated with intensities (G) from 0 to 100 s(-1). Of the two instruments selected to analyse flocculation performance, the Dynamic Particle Analyser was shown to be the most sensitive, detecting small changes in floc growth kinetics and even floc growth under low flocculation conditions which remained undetected by the PDA. Floc size was shown to be insufficient in predicting particulate <span class="hlt">matter</span> removal by direct <span class="hlt">granular</span> filtration as measured by turbidity, although a threshold d(v) value (50 microm) could be identified for the test conditions evaluated in this project, above which turbidity was systematically lower than 0.2 NTU. PMID:21882562</p> <div class="credits"> <p class="dwt_author">Ball, T; Carrière, A; Barbeau, B</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-07-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">364</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/23989757"> <span id="translatedtitle">Explosively driven fragmentation of <span class="hlt">granular</span> materials.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">This paper investigates the explosively driven dynamics of dry and <span class="hlt">wet</span> sand. Contrary to popular belief, <span class="hlt">wet</span> sand under high strain rate loadings (10(4)s(-1)) is observed to have reduced resistance against flow compared to the dry sand, which is supported by a noticeably enhanced expansion before the breakup followed by an increased number of fragments. Even a small amount of interstitial oil (3.2 wt.%) suffices to substantially reduce the size of fragments whose average mass only amounts to 60% of the mass of the dry sand fragments. To predict the instability onset of the expanding sand shell, a kinetic instability model is proposed based on an instability criterion involving the opposing forces of stabilizing inertial pressures and destabilizing viscous resistance. The interstitial oil leads to a smaller viscous resistance of <span class="hlt">wet</span> sand by the lubrication effect as well as lessening the degree of shock compaction. The dominance of viscous resistance thus commences later for the <span class="hlt">wet</span> sand shell until a smaller thickness allows the inertial forces to be overtaken. Moreover, multi-shear localizations rather than interface instability are identified as the dominant mechanism for the instability onset of the expanding sand shells. PMID:23989757</p> <div class="credits"> <p class="dwt_author">Xue, Kun; Li, Fangfang; Bai, Chunhua</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-08-30</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">365</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/54306113"> <span id="translatedtitle">Different Effects of Roughness (<span class="hlt">Granularity</span>) and Hydrophobicity</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">With thanks to Stefan Doerr and Jorge Mataix-Solera for their invitation Superhydrophobicity is an interesting effect that appears to be simple on the outset; increased surface area from roughness increases interfacial area and therefore energy loss or gain. More extreme roughness prevents total <span class="hlt">wetting</span>, resulting in gas pockets present at the surface and a drastic change in the properties of</p> <div class="credits"> <p class="dwt_author">Neil Shirtcliffe; Glen McHale; Christopher Hamlett; Michael Newton</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">366</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2006AGUFM.A43A0126H"> <span id="translatedtitle"><span class="hlt">Wetting</span> and Non-<span class="hlt">Wetting</span> Models of Black Carbon Activation</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We present the results of recent modeling studies on the activation of black carbon (BC) aerosol to form cloud condensation nuclei (CCN). We use a model of BC activation based on a general modification of the Koehler equation for insoluble activation in which we introduce a term based on the activity of water adsorbed on the particle surface. We parameterize the model using the free energy of adsorption, a parameter directly comparable to laboratory measurements of water adsorption on carbon. Although the model of the water- surface interaction is general, the form of the activation equation that results depends upon a further model of the distribution of water on the particle. One possible model involves the symmetric growth of a water shell around the isoluble particle core (<span class="hlt">wetting</span>). This model predicts upper and lower bounding curves for the activation supersaturation given by the range of water interaction energies from hydrophobic to hydrophilic which are in agreement with a large body of recent activation data. The resulting activation diameters are from 3 to 10 times smaller than activation of soluble particles of identical dry diameter. Another possible model involves an exluded liquid droplet growing in contact with the particle (non-<span class="hlt">wetting</span>). The geometry of this model much more resembles classic assumptions of heterogeneous nucleation theory. This model can yield extremely high activation supersaturation as a function of diameter, as has been observed in some experiments, and enables calculations in agreement with some of these results. We discuss these two geometrical models of water growth, the different behaviors predicted by the resulting activation equation, and the means to determine which model of growth is appropriate for a given BC particle characterized by either water interaction energy or morphology. These simple models enable an efficient and physically reasonable means to calculate the activation of BC aerosol to form CCN based upon a single parameterization in the water interaction energy.</p> <div class="credits"> <p class="dwt_author">Henson, B. F.; Laura, S.</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">367</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/783207"> <span id="translatedtitle">COMPACTION WAVE PROFILES IN <span class="hlt">GRANULAR</span> HMX</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Meso-scale simulations of a compaction wave in a <span class="hlt">granular</span> bed of HMX have been performed. The grains are fully resolved in order that the change in porosity across the wave front is determined by the elastic-plastic response of the grains rather than an empirical law for the porosity as a function of pressure. Numerical wave profiles of the pressure and velocity are compared with data from a gas gun experiment. The experiment used an initial porosity of 36%, and the wave had a pressure comparable to the yield strength of the grains. The profiles are measured at the front and back of the <span class="hlt">granular</span> bed. The transit time for the wave to travel between the gauges together with the Hugoniot jump conditions determines the porosity behind the wave front. In the simulations the porosity is determined by the yield strength and stress concentrations at the contact between grains. The value of the yield strength needed to match the experiment is discussed. Analysis of the impedance match of the wave at the back gauge indicates that the compaction wave triggers a small amount of burn, less than 1% mass fraction, on the micro-second time scale of the experiment.</p> <div class="credits"> <p class="dwt_author">R. MENIKOFF</p> <p class="dwt_publisher"></p> <p class="publishDate">2001-06-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">368</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2005JGRB..110.8409A"> <span id="translatedtitle">Influence of particle characteristics on <span class="hlt">granular</span> friction</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We report on laboratory experiments designed to illuminate grain-scale deformation mechanisms within fault gouge. We vary particle size distribution, grain and surface roughness, and gouge layer thickness to better understand how grain sliding, rolling, dilation, and compaction affect the strength and stability of <span class="hlt">granular</span> fault gouge. The experiments employed the double direct shear testing geometry and were run at room temperature, controlled humidity, and shearing rates from 0.1 to 3000 ?m/s. Experiments were carried out under constant normal stress of 5 and 10 MPa and thus within a nonfracture loading regime where sliding friction for smooth, spherical particles is measurably lower than for rough, angular particles. We compare results from shear between smooth boundaries, where we hypothesize that grain boundary sliding is the dominant deformation mechanism, and roughened surfaces, where rolling and <span class="hlt">granular</span> dilation contribute to shear deformation. We find that particle angularity and bounding surface roughness increase the frictional strength within sheared layers, indicating differences in particle reorganization due to these factors. In gouge material composed of <30% angular grains we observe repetitive stick-slip sliding where stress drop decreases while preinstability creep increases with increasing gouge layer thickness. Our data show significant differences in stick-slip characteristics as a function of gouge layer thickness and particle size, which we interpret in terms of the mechanics of grain bridges that support forces on the layers. We suggest that force chains exhibit qualitative differences as a function of grain angularity and bounding surface roughness.</p> <div class="credits"> <p class="dwt_author">Anthony, Jennifer L.; Marone, Chris</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-08-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">369</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2006AGUFMNG43C1163D"> <span id="translatedtitle">The dynamics of <span class="hlt">granular</span> impact cratering</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary"><span class="hlt">Granular</span> media can exhibit both solid- and liquid-like behavior. This is familiar in everyday life, and underlies a wealth of applications and geophysical phenomena. One simple laboratory experiment to quantify this is to drop a ball into a bucket of sand, and to study the scaling of penetration vs system parameters. Earlier we discovered that the penetration is proportional to the one-third power of drop distance and the two-thirds power of ball diameter. This connects directly to the depth-average force acting between medium and ball. To tease apart separate position- and speed-dependent contributions to the instantaneous stopping force, we now report on high-resolution measurements of impact dynamics using a novel apparatus. We find that the force grows with depth, independent of speed, and that it grows with the square of speed, independent of depth. We also find that seemingly-contradictory results of prior researchers can all be accounted for by various limits of such a force law. This <span class="hlt">granular</span> mechanics must ultimately account for other behavior such as jetting and crater morphology.</p> <div class="credits"> <p class="dwt_author">Durian, D.; Katsuragi, H.</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">370</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/1030312"> <span id="translatedtitle">Pressure-shear experiments on <span class="hlt">granular</span> materials.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Pressure-shear experiments were performed on <span class="hlt">granular</span> tungsten carbide and sand using a newly-refurbished slotted barrel gun. The sample is a thin layer of the <span class="hlt">granular</span> material sandwiched between driver and anvil plates that remain elastic. Because of the obliquity, impact generates both a longitudinal wave, which compresses the sample, and a shear wave that probes the strength of the sample. Laser velocity interferometry is employed to measure the velocity history of the free surface of the anvil. Since the driver and anvil remain elastic, analysis of the results is, in principal, straightforward. Experiments were performed at pressures up to nearly 2 GPa using titanium plates and at higher pressure using zirconium plates. Those done with the titanium plates produced values of shear stress of 0.1-0.2 GPa, with the value increasing with pressure. On the other hand, those experiments conducted with zirconia anvils display results that may be related to slipping at an interface and shear stresses mostly at 0.1 GPa or less. Recovered samples display much greater particle fracture than is observed in planar loading, suggesting that shearing is a very effective mechanism for comminution of the grains.</p> <div class="credits"> <p class="dwt_author">Reinhart, William Dodd (Sandia National Laboratories, Albuquerque, NM); Thornhill, Tom Finley, III (, Sandia National Laboratories, Albuquerque, NM); Vogler, Tracy John; Alexander, C. Scott (Sandia National Laboratories, Albuquerque, NM)</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-10-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">371</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/16802932"> <span id="translatedtitle">Dynamics of random packings in <span class="hlt">granular</span> flow.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">We present a multiscale simulation algorithm for amorphous materials, which we illustrate and validate in a canonical case of dense <span class="hlt">granular</span> flow. Our algorithm is based on the recently proposed spot model, where particles in a dense random packing undergo chainlike collective displacements in response to diffusing "spots" of influence, carrying a slight excess of interstitial free volume. We reconstruct the microscopic dynamics of particles from the "coarse grained" dynamics of spots by introducing a localized particle relaxation step after each spot-induced block displacement, simply to enforce packing constraints with a (fairly arbitrary) soft-core repulsion. To test the model, we study to what extent it can describe the dynamics of up to 135,000 frictional, viscoelastic spheres in <span class="hlt">granular</span> drainage simulated by the discrete-element method (DEM). With only five fitting parameters (the radius, volume, diffusivity, drift velocity, and injection rate of spots), we find that the spot simulations are able to largely reproduce not only the mean flow and diffusion, but also some subtle statistics of the flowing packings, such as spatial velocity correlations and many-body structural correlations. The spot simulations run over 100 times faster than the DEM and demonstrate the possibility of multiscale modeling for amorphous materials, whenever a suitable model can be devised for the coarse-grained spot dynamics. PMID:16802932</p> <div class="credits"> <p class="dwt_author">Rycroft, Chris H; Bazant, Martin Z; Grest, Gary S; Landry, James W</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-05-24</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">372</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3692194"> <span id="translatedtitle">Congenital <span class="hlt">granular</span> cell epulis of a newborn</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">The congenital <span class="hlt">granular</span> cell epulis (CGCE) is a rare tumor, which is apparent at birth. The histogenesis is still uncertain, but several theories, including origin from epithelial, undifferentiated mesenchymal cells, pericytes, fibroblasts, smooth muscle cells, and nerve-related cells have been proposed. This case report describes management of a 2-day-old baby girl having a large, round, soft, single 3 × 4 cm, pedunculated swelling, on the lower anterior ridge, which was causing difficulty in feeding. Clinical diagnosis of congenital epulis (CE) was made and lesion was excised under conscious sedation. A vessel running over the surface of the lesion was continuous on the alveolar ridge. To reduce intra-operative hemorrhage transfixion suture was passed around the vessel on the alveolar ridge. Then the lesion was excised from the base of peduncle with a scalpel. Histopathologically, the diagnosis of a congenital <span class="hlt">granular</span> cell lesion of the jaw was given. Follow up of 3 months shows no signs of recurrence. CGCE may interfere with feeding, requiring a conservative excision as soon as the child is fit to undergo surgery. Tendency for recurrence and malignant transformation has not been documented.</p> <div class="credits"> <p class="dwt_author">Bang, Kshitij O.; Bodhade, Ashish S.; Dive, Alka M.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">373</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/22233910"> <span id="translatedtitle">Strength characteristics of aerobic <span class="hlt">granular</span> sludge.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Aerobic <span class="hlt">granular</span> sludge has a number of advantages over conventional activated sludge flocs, such as cohesive and strong matrix, fast settling characteristic, high biomass retention and ability to withstand high organic loadings, all aspects leading towards a compact reactor system. Still there are very few studies on the strength of aerobic granules. A procedure that has been used previously for anaerobic <span class="hlt">granular</span> sludge strength analysis was adapted and used in this study. A new coefficient was introduced, called a stability coefficient (S), to quantify the strength of the aerobic granules. Indicators were also developed based on the strength analysis results, in order to categorize aerobic granules into three levels of strength, i.e. very strong (very stable), strong (stable) and not strong (not stable). The results indicated that aerobic granules grown on acetate were stronger (high density: >150 g T SSL(-1) and low S value: 5%) than granules developed on sewage as influent. A lower value of S indicates a higher stability of the granules. PMID:22233910</p> <div class="credits"> <p class="dwt_author">Nor-Anuar, A; Ujang, Z; van Loosdrecht, M C M; de Kreuk, M K; Olsson, G</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">374</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013AIPC.1542..795A"> <span id="translatedtitle">Shearbanding and inhomogeneous states in <span class="hlt">granular</span> fluid</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">In micro-structural fluids, the homogeneous shear flow breaks into alternate regions of low and high shear rates (i.e., shear localization), respectively, when the applied shear rate exceeds a critical value and this is known as gradient banding. On the other hand, if the applied shear stress exceeds a critical value, the homogeneous flow separates into bands of different shear stresses (having the same shear rate) along the vorticity (spanwise) direction, leading to stress localization, and the resulting pattern is dubbed vorticity banding. Here we provide a brief overview of our recent work on nonlinear order-parameter theory to describe various pattern formation scenario in a sheared <span class="hlt">granular</span> fluid, with a specific focus on the vorticity-banding phenomena. The analysis holds for any general constitutive model, but the results are presented for a kinetic-theory constitutive model that holds for rapid <span class="hlt">granular</span> flows. Our theory predicts that the vorticity banding can occur via supercritical/subcritical pitchfork and subcritical Hopf bifurcations in dilute and dense flows, respectively, resulting in an inhomogeneous state of shear stress and pressure.</p> <div class="credits"> <p class="dwt_author">Alam, Meheboob; Shukla, Priyanka</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-06-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">375</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012JAP...112i3917T"> <span id="translatedtitle">Effect of inhomogeneous microstructure of <span class="hlt">granular</span> layer on inter <span class="hlt">granular</span>/inter layer exchange coupling in stacked perpendicular recording media</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The effect of inhomogeneous microstructure of <span class="hlt">granular</span> layer on inter <span class="hlt">granular</span>/inter layer exchange coupling in stacked perpendicular recording media is studied by varying SiO2 content of CoCrPt-SiO2 <span class="hlt">granular</span> layer. From cross-section and plane-view TEM observation, it can be concluded that each magnetic grain at cap layer (CL) grows on one magnetic grain of <span class="hlt">granular</span> layer (GL), and inhomogeneous nucleation site at GL leads to inhomogeneous initial growth of continuous layer at CL. This phenomenon leads to the increase of inter <span class="hlt">granular</span> coupling fluctuation in CL. Evaluation of inter <span class="hlt">granular</span> coupling between magnetic grains at GL in stacked media with CL deposited directly on GL shows average and fluctuation of exchange coupling constant of around 2.9 erg/cm2 and 0.6 erg/cm2. In order to reduce the inter <span class="hlt">granular</span> coupling, spacer layer (SL) with Pd material was inserted between GL and CL. As a result, average and fluctuation of exchange coupling constant decrease to 1.4 erg/cm2 and 0.3 erg/cm2 which suggests that by inserting a SL with small ferromagnetic exchange coupling between GL and CL will make it possible to control the inter <span class="hlt">granular</span> coupling between magnetic grains at GL with CoCrPt-oxide material.</p> <div class="credits"> <p class="dwt_author">Tham, Kim Kong; Saito, Shin; Hasegawa, Daiji; Itagaki, Norikazu; Hinata, Shintaro; Ishibashi, Shinichi; Takahashi, Migaku</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-11-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">376</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013CRPhy..14..531B"> <span id="translatedtitle"><span class="hlt">Wetting</span> by solid helium, a model system</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">This is a review of the <span class="hlt">wetting</span> properties of solid helium on various solid substrates. Due to its extreme purity and to its very fast growth dynamics, solid helium 4 is often considered as a model system in materials science. Several <span class="hlt">wetting</span> phenomena have been studied with helium 4 crystals, namely contact angles on solid substrates with variable roughness, <span class="hlt">wetting</span> on graphite where epitaxial growth takes place, the roughening transition as a function of film thickness, the <span class="hlt">wetting</span> of grain boundaries by the liquid phase.</p> <div class="credits"> <p class="dwt_author">Balibar, Sébastien</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-08-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">377</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2002PhRvE..66d1304S"> <span id="translatedtitle">Method of moments for the dilute <span class="hlt">granular</span> flow of inelastic spheres</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Some peculiar features of <span class="hlt">granular</span> materials (smooth, identical spheres) in rapid flow are the normal pressure differences and the related anisotropy of the velocity distribution function f(1). Kinetic theories have been proposed that account for the anisotropy, mostly based on a generalization of the Chapman-Enskog expansion [N. Sela and I. Goldhirsch, J. Fluid Mech. 361, 41 (1998)]. In the present paper, we approach the problem differently by means of the method of moments; previously, similar theories have been constructed for the nearly elastic behavior of <span class="hlt">granular</span> <span class="hlt">matter</span> but were not able to predict the normal pressures differences. To overcome these restrictions, we use as an approximation of the f(1) a truncated series expansion in Hermite polynomials around the Maxwellian distribution function. We used the approximated f(1) to evaluate the collisional source term and calculated all the resulting integrals; also, the difference in the mean velocity of the two colliding particles has been taken into account. To simulate the <span class="hlt">granular</span> flows, all the second-order moment balances are considered together with the mass and momentum balances. In balance equations of the Nth-order moments, the (N+1)th-order moments (and their derivatives) appear: we therefore introduced closure equations to express them as functions of lower-order moments by a generalization of the ``elementary kinetic theory,'' instead of the classical procedure of neglecting the (N+1)th-order moments and their derivatives. We applied the model to the translational flow on an inclined chute obtaining the profiles of the solid volumetric fraction, the mean velocity, and all the second-order moments. The theoretical results have been compared with experimental data [E. Azanza, F. Chevoir, and P. Moucheront, J. Fluid Mech. 400, 199 (1999); T. G. Drake, J. Fluid Mech. 225, 121 (1991)] and all the features of the flow are reflected by the model: the decreasing exponential profile of the solid volumetric fraction, the parabolic shape of the mean velocity, the constancy of the <span class="hlt">granular</span> temperature and of its components. Besides, the model predicts the normal pressures differences, typical of the <span class="hlt">granular</span> materials.</p> <div class="credits"> <p class="dwt_author">Strumendo, Matteo; Canu, Paolo</p> <p class="dwt_publisher"></p> <p class="publishDate">2002-10-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">378</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2011JAGeo...5..163E"> <span id="translatedtitle">Prediction of troposphere <span class="hlt">wet</span> delay</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The <span class="hlt">wet</span> delay is one of the most difficult sources of error to quantify in global navigation satellite systems (GNSS) due to its spatial and temporal variability. However, its estimation is vital in some applications, such as in Precise Point Positioning (PPP), network real-time kinematic and weather forecast. Such estimation is usually carried out for its projected component along the zenith, defined as the zenith <span class="hlt">wet</span> delay (ZWD). Prediction of the ZWD is important if there is a break in its estimation, and in providing initial values for future processing. In this paper, prediction modeling for the ZWD is investigated. An autocorrelation study was first performed on ZWD data over three different days at the international GNSS service station ONSALA to provide an insight into the temporal correlations among ZWDs. The choice of this station was based on the availability of reliable ZWD data measured by water vapor radiometers, which provide a reference for assessment of the accuracy of predicted values. Results have shown that successive ZWD estimates are significantly correlated for up to 1.7 hours. Different trend and smoothing prediction models were then investigated. Since prediction of ZWD requires continuous data sequence, interpolation methods of possible missing ZWD values are discussed. The use of linear interpolation or a cubic Hermite polynomial was found to be sufficient for interpolation of ZWD. Test results of prediction models show that the single-exponential smoothing model was the best performer where ZWD estimates were forecasted with a root mean square error of less than 1 cm for up to two hours.</p> <div class="credits"> <p class="dwt_author">El-Mowafy, Ahmed; Lo, Johnny</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">379</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/172193"> <span id="translatedtitle">Dark <span class="hlt">Matter</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">These proceedings represent papers presented at the Astrophysics conference in Maryland, organized by NASA Goddard Space Flight Center and the University of Maryland. The topics covered included low mass stars as dark <span class="hlt">matter</span>, dark <span class="hlt">matter</span> in galaxies and clusters, cosmic microwave background anisotropy, cold and hot dark <span class="hlt">matter</span>, and the large scale distribution and motions of galaxies. There were eighty five papers presented. Out of these, 10 have been abstracted for the Energy Science and Technology database. (AIP)</p> <div class="credits"> <p class="dwt_author">Holt, S. S.; Bennett, C. L. [eds.] [NASA Goddard SpaceFlight Center, Greenbelt, MD 20771 (United States)</p> <p class="dwt_publisher"></p> <p class="publishDate">1995-12-31</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">380</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3770008"> <span id="translatedtitle">An Unusual <span class="hlt">Granular</span> Cell Tumour of the Buttock and a Review of <span class="hlt">Granular</span> Cell Tumours</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary"><span class="hlt">Granular</span> cell tumours, first described by Abrikossoff in 1926, are known to occur in skin, connective tissue, breast, gastrointestinal and genital tracts. While they are rare, they are more common in people of African descent and show a slight female preponderance, usually presenting as solitary and painless masses. Less than 10% of occurrences are multiple, and fewer than 3% of tumours behave in a malignant fashion. The mean age, at presentation, is 40–60 years. We report a case of <span class="hlt">granular</span> cell tumour in a young white male presenting with a painful soft tissue tumour in his buttock. The presentation is unusual because of the age, patient demographic, body site, and clinical presentation. The clinical and histological aspects are reviewed in the context of this clinical case and the associated literature.</p> <div class="credits"> <p class="dwt_author">Paul, Sharad P.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-01-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_18");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return 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showDiv("page_21");' href="#" title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">381</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/23835468"> <span id="translatedtitle">Rebound of a confined <span class="hlt">granular</span> material: combination of a bouncing ball and a <span class="hlt">granular</span> damper.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">A ball dropped over a solid surface bounces several times before a complete stop. The bouncing can be reduced by introducing a liquid into the ball; however, the first rebound remains largely unaffected by the fluid. <span class="hlt">Granular</span> materials can also work as dampers. We investigated the rebound of a container partially filled with a given mass of grains mi. During the collision, the kinetic energy of the container is partially transferred to the grains, the rebound is damped, and the fast energy dissipation through inter-particle collisions and friction decreases the bouncing time dramatically. For grain-filled cylinders, a completely inelastic collision (zero rebound) is obtained when mi ? 1.5?omc, where ?o and mc are the coefficient of restitution and mass of the empty container. For grain-filled spheres, the first rebound is almost undamped, but the second collision is completely inelastic if mi ? mc. These findings are potentially useful to design new <span class="hlt">granular</span> damping systems. PMID:23835468</p> <div class="credits"> <p class="dwt_author">Pacheco-Vázquez, F; Dorbolo, S</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-07-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">382</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/49430748"> <span id="translatedtitle">The flow regime during the crystallization state and convection state on a vibrating <span class="hlt">granular</span> bed</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">It is possible to utilize the large particle distribution on the free surface and inside a vibrating <span class="hlt">granular</span> bed to understand the segregation phenomenon and the <span class="hlt">granular</span> motion states in the vibrating bed. In this study we strive to analyze different flow regimes in a binary mixture in a <span class="hlt">granular</span> vibrating bed. The <span class="hlt">granular</span> temperature of large particles on the</p> <div class="credits"> <p class="dwt_author">Shih-Chang Tai; Shu-San Hsiau</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">383</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.springerlink.com/index/qq3735538104258x.pdf"> <span id="translatedtitle">A lymphoproliferative disorder of <span class="hlt">granular</span> lymphocytes with a novel phenotype and suppressor function</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">In this study we have identified and characterized an expanded <span class="hlt">granular</span> lymphocyte population in a patient with anemia and granulocytopenia. <span class="hlt">Granular</span> lymphocytes were identified through the presence of cytoplasmic azurophilic granules, the dispersed <span class="hlt">granular</span> pattern of cytochemical staining for acid hydrolases, and the ultrastructural localization of acid phosphatase within the granules. The surface phenotype of the <span class="hlt">granular</span> lymphocytes was E+,</p> <div class="credits"> <p class="dwt_author">Alan Landay; Man-Chiu Poon; Loran T. Clement; Carlo E. Grossi</p> <p class="dwt_publisher"></p> <p class="publishDate">1984-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">384</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/16206844"> <span id="translatedtitle">Spatial variability of characteristics and origins of urban <span class="hlt">wet</span> weather pollution in combined sewers.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">An experimental on-site observatory of urban pollutant loads in combined sewers was created in the centre of Paris to quantify and characterise the dry and <span class="hlt">wet</span> weather flow in relation to spatial scale. Eight rainfall events were studied from April 2003 to May 2004. Samples were analysed for suspended solids, organic <span class="hlt">matter</span>, nitrogen and heavy metals. Results confirm the extent of <span class="hlt">wet</span> weather pollution. They have shown the relative homogeneity of SS and organic <span class="hlt">matter</span> characteristics from one urban catchment area to another. Two groups of heavy metals were identified. The first one concerns Cu, which has a higher concentration in <span class="hlt">wet</span> weather flow (WWF) than in dry weather flow (DWF), and runoff. The second includes Cd, Pb and Zn, where higher concentrations were measured in urban runoff than in WWF and DWF. A first evaluation of contribution of wastewater, urban runoff and sewer deposit erosion sources to <span class="hlt">wet</span> weather pollution was established and has highlighted the contribution of wastewater and sewer deposits to this pollution. However, it has shown that sewer deposit erosion remains an important source of <span class="hlt">wet</span> weather pollution at different spatial scales. PMID:16206844</p> <div class="credits"> <p class="dwt_author">Kafi-Benyahia, M; Gromaire, M G; Chebbo, G</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">385</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013AIPC.1542..559C"> <span id="translatedtitle">Dispersive behavior and acoustic scaling in <span class="hlt">granular</span> rocks</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Handling and making decisions based on data taken at different scales is a critical issue in the design of exploration and production tasks in the oil industry. Acoustic data is the classical example of the integration of dissimilar scales (i.e. seismic, well logs, lab data) where there is a scale dependent velocity. An understanding of the acoustic dispersion phenomenon in <span class="hlt">granular</span> samples is needed. A detailed numerical work was conducted in order to establish the relationship between frequency and propagation speed for an acoustical pulse induced in simulated <span class="hlt">granular</span> materials. The <span class="hlt">granular</span> samples were generated with different grain size distributions while porosity and pressure were targeted and kept invariant using the grain radii expansion method. A sinusoidal burst with frequencies from 10Hz to 1MHz was applied and the corresponding acoustical speeds were estimated for each frequency. A coherent sigmoid dispersion relationship was obtained for each <span class="hlt">granular</span> sample. The asymptotic boundaries for the dispersion function reflect the limiting cases for the wavelength/heterogeneity ratio in the <span class="hlt">granular</span> pack. The lower speed asymptote was explained as the mean field value while upper speed asymptote can be understood based on a ray theory approximation scaled by a parameter we defined as the ``acoustic tortuosity factor''. This factor reflects the intricate acoustical path due to the texture of the stress network developed in the <span class="hlt">granular</span> samples and can be used together with the sigmoid dispersive relationship to describe and clarify the scale discrepancy between different source acoustic data in <span class="hlt">granular</span> materials.</p> <div class="credits"> <p class="dwt_author">Carlos, Santos; Vanessa, Urdaneta; Ernesto, Medina; Xavier, García</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-06-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">386</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/15244559"> <span id="translatedtitle">Slow drag in <span class="hlt">granular</span> materials under high pressure.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">The resistance offered by a cylindrical rod to creeping cross flow of <span class="hlt">granular</span> materials under pressure is investigated. The experimental system consists of a confined bed of <span class="hlt">granular</span> particles, which are compacted under high pressure to consolidate the <span class="hlt">granular</span> medium. A cylindrical rod is pulled at a constant and slow rate through the <span class="hlt">granular</span> medium, and the measured pulling resistance is characterized as a drag force. The influence of various parameters such as the velocity of the cylindrical rod, the rod diameter and length, the <span class="hlt">granular</span> particle size, and the compaction pressure on the required drag force is investigated experimentally. Nondimensional analysis is performed to simplify the relationships between these variables. The results show that the drag force is independent of the drag velocity, is linearly proportional to compaction pressure and rod diameter, and increases with rod length and particle size. Additional compaction experiments show that the effective density of the <span class="hlt">granular</span> bed increases linearly with pressure, and similar behavior is noted for all particle sizes. These results should prove useful in the development of constitutive equations that can describe the motion of solid objects through compacted <span class="hlt">granular</span> media under high pressure, such as during ballistic penetration of soils or ceramic armors. PMID:15244559</p> <div class="credits"> <p class="dwt_author">Zhou, Fuping; Advani, Suresh G; Wetzel, Eric D</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-06-16</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">387</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2004PhRvE..69f1306Z"> <span id="translatedtitle">Slow drag in <span class="hlt">granular</span> materials under high pressure</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The resistance offered by a cylindrical rod to creeping cross flow of <span class="hlt">granular</span> materials under pressure is investigated. The experimental system consists of a confined bed of <span class="hlt">granular</span> particles, which are compacted under high pressure to consolidate the <span class="hlt">granular</span> medium. A cylindrical rod is pulled at a constant and slow rate through the <span class="hlt">granular</span> medium, and the measured pulling resistance is characterized as a drag force. The influence of various parameters such as the velocity of the cylindrical rod, the rod diameter and length, the <span class="hlt">granular</span> particle size, and the compaction pressure on the required drag force is investigated experimentally. Nondimensional analysis is performed to simplify the relationships between these variables. The results show that the drag force is independent of the drag velocity, is linearly proportional to compaction pressure and rod diameter, and increases with rod length and particle size. Additional compaction experiments show that the effective density of the <span class="hlt">granular</span> bed increases linearly with pressure, and similar behavior is noted for all particle sizes. These results should prove useful in the development of constitutive equations that can describe the motion of solid objects through compacted <span class="hlt">granular</span> media under high pressure, such as during ballistic penetration of soils or ceramic armors.</p> <div class="credits"> <p class="dwt_author">Zhou, Fuping; Advani, Suresh G.; Wetzel, Eric D.</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-06-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">388</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/1989STIN...9014518L"> <span id="translatedtitle"><span class="hlt">Granular</span> flow: Numerical simulation of dry <span class="hlt">granular</span> flows and calculation of hydrodynamic interactions in suspensions</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Research emphasized two major topics: determination of the flow behavior of rapidly shearing dry <span class="hlt">granular</span> solids and calculation of hydrodynamics forces in creeping flows of suspensions of spherical particles. Discrete particle computer models that calculate the motion of each inelastic, frictional particle in large assemblies were applied to the simulation of dry <span class="hlt">granular</span> flows. A hard sphere model, employing instantaneous collisions and straight line trajectories between collisions, was used to perform binary mixture calculations with size ratios from 1 to 4. These simulations showed a stronger sample size dependence than previously recognized and qualitatively confirmed earlier results that stresses in shearing mixtures with large size ratios are lower than predicted by current theories. As part of the study of dry <span class="hlt">granular</span> flows we also added new boundary conditions to the models, translated them to standard FORTRAN 77 for portability and continued existing collaborative efforts and established new collaborative research agreements with various University researchers. The suspension modeling portion of this research emphasized development of new accurate and efficient numerical schemes for calculating hydrodynamic interactions in suspensions of spherical particles. The method is based on a multipole moment expansion of the induced force density acting on the fluid at the surface of each particle. The convergence of the multipole expansion was improved by including the short-range lubrication forces explicitly. Numerical results for the viscosity, diffusion constant, sedimentation velocity, and permeability were obtained and serve to illustrate the various stages of development of the method and to assess their effectiveness in representing the hydrodynamic interactions.</p> <div class="credits"> <p class="dwt_author">Ladd, Anthony J. C.; Walton, Otis R.</p> <p class="dwt_publisher"></p> <p class="publishDate">1989-07-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">389</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/26318651"> <span id="translatedtitle">A study of delamination of <span class="hlt">wet</span> clutches</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The delamination mechanism of a <span class="hlt">wet</span> clutch in an automatic transmission has not been discussed in detail. In order to investigate this mechanism, two deterioration tests were run. One was applying mechanical stroking and shear torque to a <span class="hlt">wet</span> clutch. The other was immersing cotton thread in various fluids. There was a difference in the tendency of the strength change</p> <div class="credits"> <p class="dwt_author">Hiroyuki Kaneko; Atsushi Suzuki</p> <p class="dwt_publisher"></p> <p class="publishDate">1999-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">390</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/22841278"> <span id="translatedtitle">Modeling of <span class="hlt">wet</span> jet in fluidized bed</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">A <span class="hlt">wet</span> jet zone is established in many applications wherever feeding and dispersing a liquid, solution or slurry into fluidized bed by gases is needed. In the present study, a simple mathematical model has been developed to simulate the <span class="hlt">wet</span> jet in fluidized bed. The different stages involved inside the jet zone have been estimated and analyzed.The evaporation stage of</p> <div class="credits"> <p class="dwt_author">F. Okasha; M. Miccio</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">391</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/26672445"> <span id="translatedtitle">Spreading and <span class="hlt">Wetting</span> Behaviour of Trisiloxanes</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary"><span class="hlt">Wetting</span> and spreading processes which involve surfactant solutions are widely used in numerous industrial and practical applications nowadays. The performance of different non-ionic surfactants may vary significantly and so far superspreader solutions show the most promising spreading ability. The addition of trisiloxane surfactants to water was proven to enhance <span class="hlt">wetting</span>, even on hydrophobic surfaces, on which conventional surfactants seem to</p> <div class="credits"> <p class="dwt_author">Jovana Radulovic; Khellil Sefiane; Martin E. R. Shanahan</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">392</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/60248015"> <span id="translatedtitle"><span class="hlt">Wet</span> air oxidation of propellant wastewaters</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary"><span class="hlt">Wet</span> Air Oxidation studies have been conducted on a number of propellant wastewaters, to assess destruction levels of specific propellant components. OTTO fuel, used as a torpedo propellant, and hydrazine based rocket fuels were propellants of interest. OTTO fuel wastewaters contain substantial amounts of propylene glycol dinitrate. Hydrazine based rocket fuel wastewaters contain hydrazine and unsymmetrical dimethyl hydrazine. Laboratory <span class="hlt">Wet</span></p> <div class="credits"> <p class="dwt_author">T. L. Randall; W. M. Copa; M. J. Deitrich</p> <p class="dwt_publisher"></p> <p class="publishDate">1985-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">393</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/22243184"> <span id="translatedtitle">Local anisotropy in globally isotropic <span class="hlt">granular</span> packings.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">We report on two-dimensional computer simulations of frictionless <span class="hlt">granular</span> packings at various area fractions ? above the jamming point ?(c). We measure the anisotropy in coarse-grained stress ?(s) and shear modulus ?(m) as functions of coarse-graining scale, R. ?(s) can be collapsed onto a master curve after rescaling R by a characteristic length scale ? and ?(s) by an anisotropy magnitude A. Both A and ? accelerate as ???(c) from above, consistent with a divergence at ?(c). ?(m) shows no characteristic length scale and has a nontrivial power-law form, ?(m)~R(-0.62), over almost the entire range of R at all ?. These results suggest that the force chains present in the spatial structure of the quenched stress may be governed by different physics than the anomalous elastic response near jamming. PMID:22243184</p> <div class="credits"> <p class="dwt_author">Karimi, K; Maloney, C E</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-12-23</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">394</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/23093180"> <span id="translatedtitle">Similarities between protein folding and <span class="hlt">granular</span> jamming.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Grains and glasses, widely different materials, arrest their motions upon decreasing temperature and external load, respectively, in common ways, leading to a universal jamming phase diagram conjecture. However, unified theories are lacking, mainly because of the disparate nature of the particle interactions. Here we demonstrate that folded proteins exhibit signatures common to both glassiness and jamming by using temperature- and force-unfolding molecular dynamics simulations. Upon folding, proteins develop a peak in the interatomic force distributions that falls on a universal curve with experimentally measured forces on jammed grains and droplets. Dynamical signatures are found as a dramatic slowdown of stress relaxation upon folding. Together with <span class="hlt">granular</span> similarities, folding is tied not just to the jamming transition, but a more nuanced picture of anisotropy, preparation protocol and internal interactions emerges. Results have implications for designing stable polymers and can open avenues to link protein folding to jamming theory. PMID:23093180</p> <div class="credits"> <p class="dwt_author">Jose, Prasanth P; Andricioaei, Ioan</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">395</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3104325"> <span id="translatedtitle">Emotional <span class="hlt">Granularity</span> and Borderline Personality Disorder</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">This study examined the affective dysregulation component of borderline personality disorder (BPD) from an emotional <span class="hlt">granularity</span> perspective, which refers to the specificity in which one represents emotions. Forty-six female participants meeting criteria for BPD and 51 female control participants without BPD and Axis I pathology completed tasks that assessed the degree to which participants incorporated information about valence (pleasant–unpleasant) and arousal (calm–activated) in their semantic/conceptual representations of emotions and in using labels to represent emotional reactions. As hypothesized, participants with BPD emphasized valence more and arousal less than control participants did when using emotion terms to label their emotional reactions. Implications and future research directions are discussed.</p> <div class="credits"> <p class="dwt_author">Suvak, Michael K.; Litz, Brett T.; Sloan, Denise M.; Zanarini, Mary C.; Barrett, Lisa Feldman; Hofmann, Stefan G.</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">396</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/933106"> <span id="translatedtitle">Defining and testing a <span class="hlt">granular</span> continuum element</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Continuum mechanics relies on the fundamental notion of amesoscopic volume "element" in which properties averaged over discreteparticles obey deterministic relationships. Recent work on granularmaterials suggests a continuum law may be inapplicable, revealinginhomogeneities at the particle level, such as force chains and slow cagebreaking. Here, we analyze large-scale Discrete-Element Method (DEM)simulations of different <span class="hlt">granular</span> flows and show that a "granularelement" can indeed be defined at the scale of dynamical correlations,roughly three to five particle diameters. Its rheology is rather subtle,combining liquid-like dependence on deformation rate and solid-likedependence on strain. Our results confirm some aspects of classicalplasticity theory (e.g., coaxiality of stress and deformation rate),while contradicting others (i.e., incipient yield), and can guide thedevelopment of more realistic continuum models.</p> <div class="credits"> <p class="dwt_author">Rycroft, Chris H.; Kamrin, Ken; Bazant, Martin Z.</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-12-03</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">397</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/6653064"> <span id="translatedtitle">Particle filtration in consolidated <span class="hlt">granular</span> systems</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Grain-packing algorithms are used to model the mechanical trapping of dilute suspensions of particles by consolidated <span class="hlt">granular</span> media. We study the distribution of filtrate particles, the formation of a damage zone (internal filter cake), and the transport properties of the host--filter-cake composite. At the early stages of filtration, our simulations suggest simple relationships between the structure of the internal filter cake and the characteristics of the underlying host matrix. These relationships are then used to describe the dynamics of the filtration process. Depending on the grain size and porosity of the host matrix, calculated filtration rates may either be greater than (spurt loss) or less than (due to internal clogging) those predicted by standard surface-filtration models.</p> <div class="credits"> <p class="dwt_author">Schwartz, L.M.; Wilkinson, D.J. (Schlumberger-Doll Research, Ridgefield, Connecticut 06877-4108 (United States)); Bolsterli, M. (Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)); Hammond, P. (Schlumberger Cambridge Research, High Cross, Madingley Road, Cambridge, CB3 OE (United Kingdom))</p> <p class="dwt_publisher"></p> <p class="publishDate">1993-03-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">398</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2005APS..DFD.FJ008S"> <span id="translatedtitle">Particle-size segregation in <span class="hlt">granular</span> avalanches</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Particle size segregation in avalanches occurs through shearing within the <span class="hlt">granular</span> flow. In such a flow, large particles migrate upwards, their vacated spaces being filled by smaller particles. Gray and Thornton recently proposed a simple model to capture this segregation, based on conservation of mass for two-phase flow, and basic mixture theory. The equation is a scalar conservation law in two space variables and time, but with variable coefficients corresponding to the spatially dependent velocity in shear flow. In this talk, I describe initial boundary value problems for this equation, and show numerical simulations. In simple circumstances, the problem can be solved explicitly, by combining basic multidimensional solutions to understand the overall flow and segregation. Interfaces with large particles below small are physically unstable, and this property can be explained mathematically. Indeed, unstable interfaces provide the richest multidimensional structures, one of which is analyzed in this talk.</p> <div class="credits"> <p class="dwt_author">Shearer, Michael</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-11-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">399</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013PhRvE..87e2207S"> <span id="translatedtitle">Cohesive <span class="hlt">granular</span> materials composed of nonconvex particles</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The macroscopic cohesion of <span class="hlt">granular</span> materials made up of sticky particles depends on the particle shapes. We address this issue by performing contact dynamics simulations of 2D packings of nonconvex aggregates. We find that the macroscopic cohesion is strongly dependent on the strain and stress inhomogeneities developing inside the material. The largest cohesion is obtained for nearly homogeneous deformation at the beginning of unconfined axial compression and it evolves linearly with nonconvexity. Interestingly, the aggregates in a sheared packing tend to form more contacts with fewer neighboring aggregates as the degree of nonconvexity increases. We also find that shearing leads either to an isotropic distribution of tensile contacts or to the same privileged direction as that of compressive contacts.</p> <div class="credits"> <p class="dwt_author">Saint-Cyr, Baptiste; Radjai, Farhang; Delenne, Jean-Yves; Sornay, Philippe</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-05-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">400</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2011PhRvL.107z8001K"> <span id="translatedtitle">Local Anisotropy in Globally Isotropic <span class="hlt">Granular</span> Packings</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We report on two-dimensional computer simulations of frictionless <span class="hlt">granular</span> packings at various area fractions ? above the jamming point ?c. We measure the anisotropy in coarse-grained stress ?s and shear modulus ?m as functions of coarse-graining scale, R. ?s can be collapsed onto a master curve after rescaling R by a characteristic length scale ? and ?s by an anisotropy magnitude A. Both A and ? accelerate as ???c from above, consistent with a divergence at ?c. ?m shows no characteristic length scale and has a nontrivial power-law form, ?m˜R-0.62, over almost the entire range of R at all ?. These results suggest that the force chains present in the spatial structure of the quenched stress may be governed by different physics than the anomalous elastic response near jamming.</p> <div class="credits"> <p class="dwt_author">Karimi, K.; Maloney, C. E.</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-12-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_19");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a onClick='return showDiv("page_3");' href="#">3</a> <a onClick='return showDiv("page_4");' 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onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">401</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/15244815"> <span id="translatedtitle">Gaussian kinetic model for <span class="hlt">granular</span> gases.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">A kinetic model for the Boltzmann equation is proposed and explored as a practical means to investigate the properties of a dilute <span class="hlt">granular</span> gas. It is shown that all spatially homogeneous initial distributions approach a universal "homogeneous cooling solution" after a few collisions. The homogeneous cooling solution (HCS) is studied in some detail and the exact solution is compared with known results for the hard sphere Boltzmann equation. It is shown that all qualitative features of the HCS, including the nature of overpopulation at large velocities, are reproduced by the kinetic model. It is also shown that all the transport coefficients are in excellent agreement with those from the Boltzmann equation. Also, the model is specialized to one having a velocity independent collision frequency and the resulting HCS and transport coefficients are compared to known results for the Maxwell model. The potential of the model for the study of more complex spatially inhomogeneous states is discussed. PMID:15244815</p> <div class="credits"> <p class="dwt_author">Dufty, James W; Baskaran, Aparna; Zogaib, Lorena</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-05-04</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">402</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/23453799"> <span id="translatedtitle">Livestock wastewater treatment using aerobic <span class="hlt">granular</span> sludge.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">The present study demonstrated that aerobic <span class="hlt">granular</span> sludge is capable of treating livestock wastewater from a cattle farm in a sequencing batch reactor (SBR) without the presence of support material. A lab scale SBR was operated for 80 d using 4 h cycle time with an organic loading rate (OLR) of 9 kg COD m(-3) d(-1). Results showed that the aerobic granules were growing from 0.1 to 4.1 mm towards the end of the experimental period. The sludge volume index (SVI) was 42 ml g(-1) while the biomass concentration in the reactor grew up to 10.3 g L(-1) represent excellent biomass separation and good settling ability of the granules. During this period, maximum COD, TN and TP removal efficiencies (74%, 73% and 70%, respectively) were observed in the SBR system, confirming high microbial activity in the SBR system. PMID:23453799</p> <div class="credits"> <p class="dwt_author">Othman, Inawati; Anuar, Aznah Nor; Ujang, Zaini; Rosman, Noor Hasyimah; Harun, Hasnida; Chelliapan, Shreeshivadasan</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-02-09</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">403</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2010AIPC.1227..260R"> <span id="translatedtitle">How <span class="hlt">granular</span> materials deform in quasistatic conditions</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Based on numerical simulations of quasistatic deformation of model <span class="hlt">granular</span> materials, two rheological regimes are distinguished, according to whether macroscopic strains merely reflect microscopic material strains within the grains in their contact regions (type I strains), or result from instabilities and contact network rearrangements at the microscopic level (type II strains). We discuss the occurrence of regimes I and II in simulations of model materials made of disks (2D) or spheres (3D). The transition from regime I to regime II in monotonic tests such as triaxial compression is different from both the elastic limit and from the yield threshold. The distinction between both types of response is shown to be crucial for the sensitivity to contact-level mechanics, the relevant variables and scales to be considered in micromechanical approaches, the energy balance and the possible occurrence of macroscopic instabilities.</p> <div class="credits"> <p class="dwt_author">Roux, J.-N.; Combe, G.</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-05-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">404</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/23214582"> <span id="translatedtitle">Yield loci for an anisotropic <span class="hlt">granular</span> assembly.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Yield loci of a <span class="hlt">granular</span> material are derived in case of triaxial compression carried out at constant pressure. The theory is based upon a simple micromechanical model in which particles move according to an average, homogeneous deformation. We show how the presence of an inherent anisotropy in the aggregate (typical of laboratory samples due to depositional processes) produces a deviation of the yield loci in the stress space from the expected Mohr-Coulomb prediction. That is, when the compaction pressure in an anisotropic aggregate is increased, irreversibility associated with sliding between particles occurs and this will influence the yield function in the subsequent triaxial test. Numerical simulations support the theoretical result. PMID:23214582</p> <div class="credits"> <p class="dwt_author">La Ragione, Luigi; Oger, Luc</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-10-22</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">405</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012PhRvE..85a2301G"> <span id="translatedtitle">Flexural fracturing of a cohesive <span class="hlt">granular</span> layer</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We report on the fracturing of cohesive <span class="hlt">granular</span> materials subjected to a flexural deformation. A thin layer of glass beads or of flour is deposited on an unstretchable membrane to which flexion is imposed. We observe the formation of a periodic fracturing pattern whose characteristics are discussed in comparison with results previously obtained for an in-plane stretching [Alarcon, Ramos, Vanel, Vittoz, Melo, and Géminard, Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.105.208001 105, 208001 (2010)]. In particular, at a given relative humidity, the wavelength is observed to depend linearly on the layer thickness but to be independent of the grain size, although the smallest grains are clearly more cohesive.</p> <div class="credits"> <p class="dwt_author">Géminard, Jean-Christophe; Champougny, Lorène; Lidon, Pierre; Melo, Francisco</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">406</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2007PhRvE..75d1302W"> <span id="translatedtitle">Friction and relative energy dissipation in sheared <span class="hlt">granular</span> materials</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The oscillating cylinder of a low-frequency inverted torsion pendulum is immersed into layers of noncohesive <span class="hlt">granular</span> materials, including fine sand and glass beads. The relative energy dissipation and relative modulus of the <span class="hlt">granular</span> system versus the amplitude and immersed depth of the oscillating cylinder are measured. A rheological model based on a mesoscopic picture is presented. The experimental results and rheological model indicate that small slides in the inhomogeneous force chains are responsible for the energy dissipation of the system, and the friction of the grains plays two different roles in the mechanical response of sheared <span class="hlt">granular</span> material: damping the energy and enhancing the elasticity.</p> <div class="credits"> <p class="dwt_author">Wang, Wan-Jing; Kong, Xiang-Zhao; Zhu, Zhen-Gang</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-04-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">407</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013PhRvE..87e2208K"> <span id="translatedtitle">Drag force scaling for penetration into <span class="hlt">granular</span> media</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Impact dynamics is measured for spherical and cylindrical projectiles of many different densities dropped onto a variety non-cohesive <span class="hlt">granular</span> media. The results are analyzed in terms of the material-dependent scaling of the inertial and frictional drag contributions to the total stopping force. The inertial drag force scales similar to that in fluids, except that it depends on the internal friction coefficient. The frictional drag force scales as the square-root of the density of <span class="hlt">granular</span> medium and projectile, and hence cannot be explained by the combination of <span class="hlt">granular</span> hydrostatic pressure and Coulomb friction law. The combined results provide an explanation for the previously observed penetration depth scaling.</p> <div class="credits"> <p class="dwt_author">Katsuragi, Hiroaki; Durian, Douglas J.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-05-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">408</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/20866460"> <span id="translatedtitle">Sinking of light intruders in a shaken <span class="hlt">granular</span> bed.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">We present an experimental study of the displacement of a light intruder immersed in a vibrated <span class="hlt">granular</span> bed. Using high speed video we resolve the motion, during one cycle of oscillation, of a cylindrical object inside a Plexiglas box partially filled with grains. We report experimental evidence that, in the absence of convection, at least two forces are behind the intruder's motion: an air drag force--due to the airflow through the <span class="hlt">granular</span> bed--and a buoyancy force produced by an air-mediated <span class="hlt">granular</span> fluid. PMID:20866460</p> <div class="credits"> <p class="dwt_author">Sánchez, Iván; Gutiérrez, Gustavo; Zuriguel, Iker; Maza, Diego</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-06-23</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">409</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/40205383"> <span id="translatedtitle">Dynamics of electrostatically driven <span class="hlt">granular</span> media: Effects of humidity</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">We performed experimental studies of the effect of humidity on the dynamics of electrostatically driven <span class="hlt">granular</span> materials. Both conducting and dielectric particles undergo a phase transition from an immobile state (<span class="hlt">granular</span> solid) to a fluidized state (<span class="hlt">granular</span> gas) with increasing applied field. Spontaneous precipitation of solid clusters from the gas phase occurs as the external driving is decreased. The clustering dynamics in conducting particles is primarily controlled by screening of the electric field but is aided by cohesion due to humidity. It is shown that humidity effects dominate the clustering process with dielectric particles.</p> <div class="credits"> <p class="dwt_author">Howell, D. W.; Aronson, Igor S.; Crabtree, G. W.</p> <p class="dwt_publisher"></p> <p class="publishDate">2001-05-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">410</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/19678926"> <span id="translatedtitle"><span class="hlt">Matter</span> and anti-<span class="hlt">matter</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Summary  The implications of anti-<span class="hlt">matter</span> (consisting of positrons and antiprotons) existing on a cosmic scale are discussed. It is\\u000a shown from a consideration of the kinetic and magnetic energy of the interstellar gas clouds and from the energy of cosmic\\u000a radiation that the ratio of anti-<span class="hlt">matter</span> to ordinary <span class="hlt">matter</span> in our Galaxy cannot exceed ~ 10-7. The importance to radio astronomy</p> <div class="credits"> <p class="dwt_author">G. E. Burbidge; F. Hoyle</p> <p class="dwt_publisher"></p> <p class="publishDate">1956-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">411</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/16608308"> <span id="translatedtitle">Experimental investigation of particle-assisted <span class="hlt">wetting</span>.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">In principle, one might prepare thin polymer membranes in an easy and economic way by generating a <span class="hlt">wetting</span> layer of a polymerizable oil on a water surface, solidifying it, and transferring it to a solid substrate. However, there is hardly any oil that <span class="hlt">wets</span> a water surface. One efficient way to assist the <span class="hlt">wetting</span> of the water surface by an oil is to mix the oil with suitable particles. Theoretically, one expects several scenarios, which depend on the contact angles of the particles with the liquid interfaces. On the basis of these calculations, one can draw phase diagrams of particle-assisted <span class="hlt">wetting</span>. In the current paper, we verify such a phase diagram of particle-assisted <span class="hlt">wetting</span> experimentally. PMID:16608308</p> <div class="credits"> <p class="dwt_author">Ding, Ailin; Goedel, Werner A</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-04-19</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">412</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013JPCM...25R5006M"> <span id="translatedtitle">Filling and <span class="hlt">wetting</span> transitions at grooved substrates</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The <span class="hlt">wetting</span> and filling properties of a fluid adsorbed on a solid grooved substrate are studied by means of a microscopic density functional theory. The grooved substrates are modelled using a solid slab, interacting with the fluid particles via long-range dispersion forces, to which a one-dimensional array of infinitely long rectangular grooves is sculpted. By investigating the effect of the groove periodicity and the width of the grooves and the ridges, a rich variety of different <span class="hlt">wetting</span> morphologies is found. In particular, we show that for a saturated ambient gas, the adsorbent can occur in one of four <span class="hlt">wetting</span> states characterized by (i) empty grooves, (ii) filled grooves, (iii) a formation of mesoscopic hemispherical caps (iv) a macroscopically <span class="hlt">wet</span> surface. The character of the transition between particular regimes, that also extend off-coexistence, sensitively depends on the model geometry. The temperature at which the system becomes completely <span class="hlt">wet</span> is considerably higher than that for a flat wall.</p> <div class="credits"> <p class="dwt_author">Malijevský, Alexandr</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-11-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">413</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1478371"> <span id="translatedtitle">Do <span class="hlt">wet</span> suits affect swimming speed?</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">A randomised cross-over trial was conducted to see if <span class="hlt">wet</span> suits increase swimming speed--a question which has been fiercely debated in the fat-growing endurance sport of Triathlon. Sixteen swimmers volunteered to undertake two 30 minute swims, one with and one without a <span class="hlt">wet</span> suit. With <span class="hlt">wet</span> suits the subjects swam an average of 24.9 lengths of a 66 m pool. Without <span class="hlt">wet</span> suits they swam 23.2 lengths. A 95% confidence interval for the difference is from 0.8 to 2.6 lengths (p less than 0.001). This result suggests that regulations about the use of <span class="hlt">wet</span> suits must be agreed internationally to ensure equal competition whilst promoting the health and safety aspects of sport.</p> <div class="credits"> <p class="dwt_author">Parsons, L; Day, S J</p> <p class="dwt_publisher"></p> <p class="publishDate">1986-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">414</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.compadre.org/per/per_reviews/media/volume1/matterandinteractions-2007.pdf"> <span id="translatedtitle"><span class="hlt">MATTER</span> & INTERACTIONS</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary"><span class="hlt">Matter</span> & Interactions is a modern calculus-based introductory curriculum that em- phasizes the power of fundamental principles, and guides students through the proc- ess of starting from these principles in analyzing physical systems, on both the mac- roscopic and the microscopic level. The continual emphasis on the application of fundamental principles and on the atomic nature of <span class="hlt">matter</span> makes possible</p> <div class="credits"> <p class="dwt_author">Ruth Chabay; Bruce Sherwood</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">415</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3315053"> <span id="translatedtitle">Neuron Deficit in the White <span class="hlt">Matter</span> and Subplate in Periventricular Leukomalacia</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">Objective The cellular basis of cognitive abnormalities in preterm infants with periventricular leukomalacia (PVL) is uncertain. One important possibility is that damage to white <span class="hlt">matter</span> and subplate neurons which are critical to the formation of the cerebral cortex occurs in conjunction with oligodendrocyte and axonal injury in PVL. We tested the hypothesis that the overall density of neurons in the white <span class="hlt">matter</span> and subplate region is significantly lower in PVL cases compared to non-PVL controls. Methods We used a computer-based method for the determination of the density of MAP2-immunolabeled neurons in the ventricular/subventricular region, periventricular white <span class="hlt">matter</span>, central white <span class="hlt">matter</span>, and subplate region in PVL cases and controls. Results There were five subtypes of subcortical neurons: <span class="hlt">granular</span>, unipolar, bipolar, inverted pyramidal, and multipolar. The neuronal density of the <span class="hlt">granular</span> neurons in each of the four regions was 54–80% lower (p?0.01) in the PVL cases (n=15) compared to controls adjusted for age and postmortem interval (n=10). The overall densities of unipolar, bipolar, multipolar, and inverted pyramidal neurons did not differ significantly between the PVL cases and controls. No <span class="hlt">granular</span> neurons expressed markers of neuronal and glial immaturity (Tuj1, doublecortin, or NG1). Interpretation These data suggest that quantitative deficits in susceptible <span class="hlt">granular</span> neurons occur in the white <span class="hlt">matter</span> distant from periventricular foci, including the subplate region, in PVL, and may contribute to abnormal cortical formation and cognitive dysfunction in preterm survivors.</p> <div class="credits"> <p class="dwt_author">Kinney, Hannah C.; Haynes, Robin L.; Xu, Gang; Andiman, Sarah E.; Folkerth, Rebecca D.; Sleeper, Lynn A; Volpe, Joseph J.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">416</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013PhRvE..88c3010N"> <span id="translatedtitle">Dynamic <span class="hlt">wetting</span> at the nanoscale</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Although the capillary spreading of a drop on a dry substrate is well studied, understanding and describing the physical mechanisms that govern the dynamics remain challenging. Here we study the dynamics of spreading of partially <span class="hlt">wetting</span> nanodroplets by combining molecular dynamics simulations and continuum phase field simulations. The phase field simulations account for all the relevant hydrodynamics, i.e., capillarity, inertia, and viscous stresses. By coordinated continuum and molecular dynamics simulations, the macroscopic model parameters are extracted. For a Lennard-Jones fluid spreading on a planar surface, the liquid slip at the solid substrate is found to be significant, in fact crucial for the motion of the contact line. Evaluation of the different contributions to the energy transfer shows that the liquid slip generates dissipation of the same order as the bulk viscous dissipation or the energy transfer to kinetic energy. We also study the dynamics of spreading on a substrate with a periodic nanostructure. Here it is found that a nanostructure with a length scale commensurate with molecular size completely inhibits the liquid slip. The dynamic spreading is thus about 30% slower on a nanostructured surface compared to one that is atomically smooth.</p> <div class="credits"> <p class="dwt_author">Nakamura, Yoshinori; Carlson, Andreas; Amberg, Gustav; Shiomi, Junichiro</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-09-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">417</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/3980382"> <span id="translatedtitle">Heat exchanges in <span class="hlt">wet</span> suits.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Flow of water under foam neoprene <span class="hlt">wet</span> suits could halve insulation that the suits provided, even at rest in cold water. On the trunk conductance of this flow was approximately 6.6 at rest and 11.4 W . m-2 . C-1 exercising; on the limbs, it was only 3.4 at rest and 5.8 W . m-2 . degrees C-1 exercising; but during vasoconstriction in the cold, skin temperatures on distal parts of limbs were lower than were those of the trunk, allowing adequate metabolic responses. In warm water, minor postural changes and movement made flow under suits much higher, approximately 60 on trunk and 30 W . m-2 . degrees C-1 on limbs, both at rest and at work. These changes in flow allowed for a wide range of water temperatures at which people could stabilize body temperature in any given suit, neither overheating when exercising nor cooling below 35 degrees C when still. Even thin people with 4- or 7- mm suits covering the whole body could stabilize their body temperatures in water near 10 degrees C in spite of cold vasodilatation. Equations to predict limits of water temperature for stability with various suits and fat thicknesses are given. PMID:3980382</p> <div class="credits"> <p class="dwt_author">Wolff, A H; Coleshaw, S R; Newstead, C G; Keatinge, W R</p> <p class="dwt_publisher"></p> <p class="publishDate">1985-03-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">418</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://oaspub.epa.gov/eims/eimsapi.dispdetail?deid=42395"> <span id="translatedtitle">DISINFECTION OF BACTERIA ATTACHED TO <span class="hlt">GRANULAR</span> ACTIVATED CARBON</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p class="result-summary">Heterotrophic plate count bacteria, coliform organisms, and pathogenic microorganisms attached to <span class="hlt">granular</span> activated carbon (GAC) particles were examined for their susceptibility to chlorine disinfection. When these bacteria were grown on carbon particles and then disinfected wit...</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">419</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ntis.gov/search/product.aspx?ABBR=ADA173015"> <span id="translatedtitle">Study of Explosive Wave Propagation in <span class="hlt">Granular</span> Materials with Microstructure.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ntis.gov/search/index.aspx">National Technical Information Service (NTIS)</a></p> <p class="result-summary">This report describes an investigation into one-dimensional stress wave propagation in <span class="hlt">granular</span> materials with microstructure. The study employs the distributed body concept advanced by Goodman and the associated wave propagation studies conducted by Nuni...</p> <div class="credits"> <p class="dwt_author">B. Rohani M. Hossain M. H. Sadd</p> <p class="dwt_publisher"></p> <p class="publishDate">1986-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">420</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/21443648"> <span id="translatedtitle">Brownian motion in <span class="hlt">granular</span> gases of viscoelastic particles</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">A theory is developed of Brownian motion in <span class="hlt">granular</span> gases (systems of many macroscopic particles undergoing inelastic collisions), where the energy loss in inelastic collisions is determined by a restitution coefficient {epsilon}. Whereas previous studies used a simplified model with {epsilon} = const, the present analysis takes into account the dependence of the restitution coefficient on relative impact velocity. The <span class="hlt">granular</span> temperature and the Brownian diffusion coefficient are calculated for a <span class="hlt">granular</span> gas in the homogeneous cooling state and a gas driven by a thermostat force, and their variation with grain mass and size and the restitution coefficient is analyzed. Both equipartition principle and fluctuation-dissipation relations are found to break down. One manifestation of this behavior is a new phenomenon of 'relative heating' of Brownian particles at the expense of cooling of the ambient <span class="hlt">granular</span> gas.</p> <div class="credits"> <p class="dwt_author">Bodrova, A. S., E-mail: bodrova@polly.phys.msu.ru; Brilliantov, N. V.; Loskutov, A. Yu. [Moscow State University (Russian Federation)</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-12-15</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_20");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a onClick='return showDiv("page_3");' href="#">3</a> <a 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href="#">11</a> <a onClick='return showDiv("page_12");' href="#">12</a> <a onClick='return showDiv("page_13");' href="#">13</a> <a onClick='return showDiv("page_14");' href="#">14</a> <a onClick='return showDiv("page_15");' href="#">15</a> <a onClick='return showDiv("page_16");' href="#">16</a> <a onClick='return showDiv("page_17");' href="#">17</a> <a onClick='return showDiv("page_18");' href="#">18</a> <a onClick='return showDiv("page_19");' href="#">19</a> <a onClick='return showDiv("page_20");' href="#">20</a> <a onClick='return showDiv("page_21");' href="#">21</a> <a style="font-weight: bold;">22</a> <a onClick='return showDiv("page_23");' href="#">23</a> <a onClick='return showDiv("page_24");' href="#">24</a> <a onClick='return showDiv("page_25");' href="#">25</a> </span> </span> <a id="NextPageLink" onclick='return showDiv("page_23");' href="#" title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">421</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ntis.gov/search/product.aspx?ABBR=DE94012065"> <span id="translatedtitle">Sealing of boreholes using natural, compatible materials: <span class="hlt">Granular</span> salt.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ntis.gov/search/index.aspx">National Technical Information Service (NTIS)</a></p> <p class="result-summary"><span class="hlt">Granular</span> salt can be used to construct high performance permanent seals in boreholes which penetrate rock salt formations. These seals are described as seal systems comprised of the host rock, the seal material, and the seal rock interface. The performanc...</p> <div class="credits"> <p class="dwt_author">R. E. Finley D. H. Zeuch J. C. Stormont J. J. K. Daemen</p> <p class="dwt_publisher"></p> <p class="publishDate">1994-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">422</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ntis.gov/search/product.aspx?ABBR=ADA362534"> <span id="translatedtitle">Regeneration of <span class="hlt">Granular</span> Activated Carbon Using Hydrothermal Technology.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ntis.gov/search/index.aspx">National Technical Information Service (NTIS)</a></p> <p class="result-summary">The economic feasibility of using <span class="hlt">granular</span> activated carbon (GAC) to remove organic contaminants from industrial and municipal wastewater is contingent upon its reuse during multiple adsorption-regeneration cycles (Van Vliet, 1991). The most common proces...</p> <div class="credits"> <p class="dwt_author">M. D. Sufnarski</p> <p class="dwt_publisher"></p> <p class="publishDate">1999-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">423</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ntis.gov/search/product.aspx?ABBR=DE86005465"> <span id="translatedtitle">Particle Deposition in <span class="hlt">Granular</span> Media. Annual Progress Report.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ntis.gov/search/index.aspx">National Technical Information Service (NTIS)</a></p> <p class="result-summary">These studies were concerned with the various problems arising from the flow of gas-solids suspensions through <span class="hlt">granular</span> media and subsequent deposition of particles throughout the media. Included also are certain information concerning the project. (ERA c...</p> <div class="credits"> <p class="dwt_author">C. Tien</p> <p class="dwt_publisher"></p> <p class="publishDate">1985-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">424</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ntis.gov/search/product.aspx?ABBR=ADA956513"> <span id="translatedtitle">Removal of Trace Organics from Groundwater Using <span class="hlt">Granular</span> Activated Carbons.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ntis.gov/search/index.aspx">National Technical Information Service (NTIS)</a></p> <p class="result-summary">The purpose of this study was to determine the feasibility of using <span class="hlt">granular</span> activated carbon for the removal of dissolved organics from ground water. The primary contaminant considered during the testing program was DIMP(Diisopropyl Methyl Phosphonate). ...</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">1977-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">425</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/21231360"> <span id="translatedtitle">Thermal transients and convective particle motion in dense <span class="hlt">granular</span> materials.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">The mechanism of dry <span class="hlt">granular</span> convection within dense <span class="hlt">granular</span> flows is mostly neglected by current analytical heat equations describing such materials, for example, in geophysical analyses of shear gouge layers of earthquake and landslide rupture planes. In dry <span class="hlt">granular</span> materials, the common assumption is that conduction by contact overtakes any other mode of heat transfer. Conversely, we discover that transient correlated motion of heated grains can result in a convective heat flux normal to the shear direction up to 3-4 orders magnitude larger than by contact conduction. Such a thermal efficiency, much higher than that of water, is appealing and might be common to other microscopically structured fluids such as <span class="hlt">granular</span> pastes, emulsions, and living cells. PMID:21231360</p> <div class="credits"> <p class="dwt_author">Rognon, P; Einav, I</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-11-17</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">426</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/1998APS..MAR.Q1405S"> <span id="translatedtitle">Drag Force In <span class="hlt">Granular</span> Media: Analog to Viscosity?</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">An analogy is often drawn between the behavior <span class="hlt">granular</span> media and that of fluids, since <span class="hlt">granular</span> media flow when poured and also conform to the shapes of their containers. Furthermore, when a solid object is pulled through a <span class="hlt">granular</span> medium, it encounters a drag force resisting its motion which is analogous to the viscous drag force on a solid object moving through a fluid. We have measured the drag force and fluctuations in the drag force on an object dipped into a moving <span class="hlt">granular</span> medium. In the limit of low velocities, we find that the drag force is almost independent of velocity and increases with increasing depth within the medium. Neither of these properties can be understood within hydrodynamical viscosity, but they can be explained quantitatively within a theoretical framework based on chains of forces among the grains. Experimental data and a comparison to the theory will be presented.</p> <div class="credits"> <p class="dwt_author">Schiffer, Peter; Pfeifer, Mark; Albert, Reka; Barabasi, Albert-Laszlo</p> <p class="dwt_publisher"></p> <p class="publishDate">1998-03-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">427</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.physics.emory.edu/faculty/weeks/lab/papers/To_PRL_01.pdf"> <span id="translatedtitle">Jamming of <span class="hlt">Granular</span> Flow in a Two-Dimensional Hopper</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary"><span class="hlt">Granular</span> systems consist of particles which interact among themselves only by interparticle contacts (1-3). In nature, many important phenomena such as avalanche, landslide, soil fluidization, and blood flow can be related to three-dimensional (3D) <span class="hlt">granular</span> flow. On the other hand, two-dimensional (2D) flow phenomena can be found in the baggage flow on conveyer belts, the transport of cans and bottles</p> <div class="credits"> <p class="dwt_author">Pik-Yin Lai; H. K. Pak</p> <p class="dwt_publisher"></p> <p class="publishDate">2001-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">428</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/35557260"> <span id="translatedtitle">Quality of poultry litter-derived <span class="hlt">granular</span> activated carbon</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Utilization of poultry litter as a source material for generating activated carbon is a value-added and environmentally beneficial approach to recycling organic waste. In this study, the overall quality of poultry litter-derived <span class="hlt">granular</span> activated carbon was systematically evaluated based on its various physical and chemical properties. <span class="hlt">Granular</span> activated carbon generated from pelletized poultry litter following a typical steam-activation procedure possessed</p> <div class="credits"> <p class="dwt_author">Guannan Qiu; Mingxin Guo</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">429</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/5377356"> <span id="translatedtitle">Particle deposition in <span class="hlt">granular</span> media. Annual progress report</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Studies performed under Contract DE-AC02-79-ER10386.A000 Particle Deposition in <span class="hlt">Granular</span> Media during the period June 1, 1979 to date are described. These studies include the design and construction of apparatus for filtration experiments and a complete trajectory analysis for the calculation of the initial collection efficiency of <span class="hlt">granular</span> media. The results of the trajectory analysis have been used to develop a generalized correlation of the collection efficiency.</p> <div class="credits"> <p class="dwt_author">Tien, C.</p> <p class="dwt_publisher"></p> <p class="publishDate">1980-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">430</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/48678096"> <span id="translatedtitle">Two Scale Model (FEM-DEM) For <span class="hlt">Granular</span> Media</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">\\u000a The macroscopic behavior of <span class="hlt">granular</span> materials, as a consequence of the interactions of individual grains at the micro scale,\\u000a is studied in this paper. A two scale numerical homogenization approach is developed. At the small-scale level, a <span class="hlt">granular</span>\\u000a structure is considered. The Representative Elementary Volume (REV) consists of a set of N polydisperse rigid discs (2D),\\u000a with random radii. This</p> <div class="credits"> <p class="dwt_author">Micha? Nitka; Gaël Combe; Cristian Dascalu; Jacques Desrues</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">431</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012EL....10034004B"> <span id="translatedtitle">Stability of a <span class="hlt">granular</span> layer on an inclined “fakir plane”</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We present here experimental results on the effect of a forest of cylinder obstacles (nails) on the stability of a <span class="hlt">granular</span> layer over a rough incline, in a so-called “fakir plane” configuration. The nail forest is found to increase the stability of the layer, the more for the densest array, and such an effect is recovered by a simple model taking into account the additional friction force exerted by the pillar forest onto the <span class="hlt">granular</span> layer.</p> <div class="credits"> <p class="dwt_author">Benito, J.; Bertho, Y.; Ippolito, I.; Gondret, P.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-11-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">432</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013AIPC.1542..465Z"> <span id="translatedtitle">Novel experimental apparatus for <span class="hlt">granular</span> experiments on basal friction</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We have designed a novel experimental apparatus to probe the mechanics of sheared quasi two-dimensional frictional <span class="hlt">granular</span> materials with tunable friction from the supporting base of the apparatus. The experiment consists of a floating layer of photoelastic disks, which is subject to deformation. Forces on the particles are measured at the particle scale, using their photoelastic properties. This novel setup makes the study of the role of basal friction on sheared <span class="hlt">granular</span> media possible.</p> <div class="credits"> <p class="dwt_author">Zheng, Hu; Dijksman, Joshua A.; Behringer, Robert P.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-06-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">433</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.springerlink.com/index/a43582464254q556.pdf"> <span id="translatedtitle">Modeling of thermal conduction in <span class="hlt">granular</span> silica aerogels</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Monolithic silica aerogels of large sizes are difficult to synthesize and manipulate. <span class="hlt">Granular</span> form is the easiest way of\\u000a conditioning them. One of the most promising applications is probably thermal superinsulation applied to the building sector.\\u000a To understand and quantify thermal conduction in <span class="hlt">granular</span> silica aerogels, numerical simulations are necessary. Our method\\u000a is based on two steps: determining properties of</p> <div class="credits"> <p class="dwt_author">S. Spagnol; B. Lartigue; A. Trombe; V. Gibiat</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">434</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/19096974"> <span id="translatedtitle">Temporally disordered <span class="hlt">granular</span> flow: A model of landslides</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">We propose and study numerically a stochastic cellular automaton model for the dynamics of <span class="hlt">granular</span> materials with temporal disorder representing random variation of the diffusion probability 1-mu(t) around threshold value 1-mu0 during the course of an avalanche. Combined with the slope threshold dynamics, the temporal disorder yields a series of secondary instabilities, resembling those in realistic <span class="hlt">granular</span> slides. When the</p> <div class="credits"> <p class="dwt_author">Bosiljka Tadic</p> <p class="dwt_publisher"></p> <p class="publishDate">1998-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">435</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/50756922"> <span id="translatedtitle"><span class="hlt">Granular</span> Computing Applied to Data-Mining of Tunnel Information</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary"><span class="hlt">Granular</span> Computing(GrC) is a new concept and novel approach to solve the complex problems and provide a method for massive data-mining in the field of artificial intelligence. This paper presents a novel method which combines the quotient space theory to the <span class="hlt">granular</span> computing for analysis of the data warehouse and data mining .This method can manage city traffic information system</p> <div class="credits"> <p class="dwt_author">Luo Zhong; Jun Wu</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">436</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/909616"> <span id="translatedtitle">Dynamics of <span class="hlt">Granular</span> Materials and Particle-Laden Flows</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Rapid <span class="hlt">granular</span> flows and particle-laden flows were studied in laboratory experiments, molecular dynamics simulations, and simulations of continuum equations. The research demonstrated that the inclusion of friction is crucial in realistic modeling of <span class="hlt">granular</span> flows; hence extensive previous analyses and simulations by many researchers for frictionless particles must be reconsidered in the light of our work. We also made the first detailed comparison between experiment and the predictions of continuum theory for <span class="hlt">granular</span> media (hydrodynamic equations). We found that shock waves easily form in <span class="hlt">granular</span> flows since the speed of sound waves (pressure fluctuations) in a <span class="hlt">granular</span> gas is small, typically 10 cm, while flow velocities are easily an order of magnitude larger. Our measurements on vertically oscillating <span class="hlt">granular</span> layers led to the development of a novel technique for continuously separating particles of different sizes. Our study of craters formed by the impact of a projectile in a <span class="hlt">granular</span> medium showed, surprisingly, that the time taken for a projectile to come to a rest in the <span class="hlt">granular</span> layer is independent of the projectile’s impact energy. Another study supported by this grant examined a vertically oscillating layer of a mixture of cornstarch and water. The discovery of stable holes in the mixture was reported widely in the popular press, e.g., Science News [15 May 2004], “Imaging poking a liquid to create holes that persist like the holes in Swiss cheese. Incredible as that might sound, a group of scientists has done it.” Further experiments on glass spheres in an aqueous solution yielded the same holey fluid phenomenon, supporting our conjecture that such holes may occur in dense concentrations of particles in solution in industrial applications.</p> <div class="credits"> <p class="dwt_author">Swinney, Harry L.</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-07-11</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">437</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/59643132"> <span id="translatedtitle">Long-range interactions in dilute <span class="hlt">granular</span> systems</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">In this thesis, on purpose, we focussed on the most challenging, longest ranging\\u000apotentials. We analyzed <span class="hlt">granular</span> media of low densities obeying 1\\/r long-range\\u000ainteraction potentials between the granules. Such systems are termed <span class="hlt">granular</span>\\u000agases and differ in their behavior from ordinary gases by dissipative interactions,\\u000ai.e., they do not conserve energy. Due to the dissipation, a unique wealth of</p> <div class="credits"> <p class="dwt_author">Micha-Klaus Müller</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">438</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/663214"> <span id="translatedtitle">Effect of finite particle interaction time in <span class="hlt">granular</span> systems</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Almost all previously published theoretical papers that propose constitutive relations for <span class="hlt">granular</span> flows use some form of kinetic theory, which neglects effects of finite particle interaction time and multiparticle interactions. In dense systems, these effects contain essential physics and determine the evolution of the stress system in <span class="hlt">granular</span> flows. In this paper, the authors shall demonstrate the importance of these effects and study the behavior of the <span class="hlt">granular</span> stress in a dense system. The particle interaction time is a random variable in a <span class="hlt">granular</span> system, and they show that its probability distribution obeys an exponential law. The temporal decay of this probability represents the destruction of contacts between particles and is related to the relaxation of the collisional stress in a <span class="hlt">granular</span> system. By considering the balance between creation and destruction of contacts, they derive a constitutive relation for collisional stress. Depending on the form of the model chosen to approximate forces developed during particle interactions, the constitutive relation can predict either viscoelastic or viscoplastic behavior of the collisional stress. Numerical simulations are performed to verify the theoretical findings and to study further the properties of dense <span class="hlt">granular</span> systems.</p> <div class="credits"> <p class="dwt_author">Zhang, D.Z.; Rauenzahn, R.M.</p> <p class="dwt_publisher"></p> <p class="publishDate">1998-07-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">439</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/23004751"> <span id="translatedtitle">Collapse of <span class="hlt">granular</span>-liquid mixtures over rigid, inclined beds.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">This work deals with the propagation of <span class="hlt">granular</span>-liquid waves over rigid beds, originated by the sudden removal of a sluice gate in a rectangular, inclined flume. In particular, we experimentally investigate the role of the initial volume ratio of <span class="hlt">granular</span> material-monodispersed plastic cylinders-to water, the flume width, and the bed roughness on the time evolution of the <span class="hlt">granular</span> front. Due to the presence of the interstitial liquid, we observed previously unreported types of collapse: (i) discontinuous flows, where the <span class="hlt">granular</span> material stops after an initial spreading, and then flows again when the liquid, initially slower than the particles, reaches the front and remobilizes it; (ii) flows evolving into uniformly progressive waves at an angle of inclination of the flume well below the angle of repose of the dry <span class="hlt">granular</span> material. We also noticed an unusual influence of the lateral confinement on the wave propagation. Indeed, the constant front velocity in the uniformly progressive state decreases when the channel width increases. We claim that the latter observation and the presence of discontinuous flows, strongly support the idea that only two-phase, stratified mathematical models can predict the behavior of unsteady, <span class="hlt">granular</span>-liquid mixtures at high concentration, such as debris flows. PMID:23004751</p> <div class="credits"> <p class="dwt_author">Berzi, D; Bossi, F C; Larcan, E</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-05-17</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">440</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013AIPC.1542..803K"> <span id="translatedtitle">Can one ``Hear'' the aggregation state of a <span class="hlt">granular</span> system?</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">If an ensemble of macroscopic particles is mechanically agitated the constant energy input is dissipated into the system by multiple inelastic collisions. As a result, the <span class="hlt">granular</span> material can exhibit, depending on the magnitude of agitation, several physical states - like a gaseous phase for high energy input or a condensed state for low agitation. Here we introduce a new method for quantifying the acoustical response of the <span class="hlt">granular</span> system. Our experimental system consists of a monodisperse packing of glass beads with a free upper surface, which is confined inside a cylindrical container. An electro-mechanical shaker exerts a sinusoidal vertical vibration at normalized accelerations well above the fluidization threshold for a monolayer of particles. By increasing the number of beads the <span class="hlt">granular</span> gas suddenly collapses if a critical threshold is exceeded. The transition can be detected easily with a microphone connected to the soundcard of a PC. From the recorded audio track a FFT is calculated in real-time. Depending on either the number of particles at a fixed acceleration or the amount of energy input for a given number of particles, the resulting rattling noise exhibits a power spectrum with either the dominating (shaker) frequency plus higher harmonics for a <span class="hlt">granular</span> crystal or a high-frequency broad-band noise for a <span class="hlt">granular</span> gas, respectively. Our new method demonstrates that it is possible to quantify analytically the subjective audio impressions of a careful listener and thus to distinguish easily between different aggregation states of an excited <span class="hlt">granular</span> system.</p> <div class="credits"> <p class="dwt_author">Kruelle, Christof A.; Sánchez, Almudena García</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-06-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_21");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" 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showDiv("page_24");' href="#">24</a> <a onClick='return showDiv("page_25");' href="#">25</a> </span> </span> <a id="NextPageLink" onclick='return showDiv("page_24");' href="#" title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">441</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012PhRvE..85e1308B"> <span id="translatedtitle">Collapse of <span class="hlt">granular</span>-liquid mixtures over rigid, inclined beds</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">This work deals with the propagation of <span class="hlt">granular</span>-liquid waves over rigid beds, originated by the sudden removal of a sluice gate in a rectangular, inclined flume. In particular, we experimentally investigate the role of the initial volume ratio of <span class="hlt">granular</span> material—monodispersed plastic cylinders—to water, the flume width, and the bed roughness on the time evolution of the <span class="hlt">granular</span> front. Due to the presence of the interstitial liquid, we observed previously unreported types of collapse: (i) discontinuous flows, where the <span class="hlt">granular</span> material stops after an initial spreading, and then flows again when the liquid, initially slower than the particles, reaches the front and remobilizes it; (ii) flows evolving into uniformly progressive waves at an angle of inclination of the flume well below the angle of repose of the dry <span class="hlt">granular</span> material. We also noticed an unusual influence of the lateral confinement on the wave propagation. Indeed, the constant front velocity in the uniformly progressive state decreases when the channel width increases. We claim that the latter observation and the presence of discontinuous flows, strongly support the idea that only two-phase, stratified mathematical models can predict the behavior of unsteady, <span class="hlt">granular</span>-liquid mixtures at high concentration, such as debris flows.</p> <div class="credits"> <p class="dwt_author">Berzi, D.; Bossi, F. C.; Larcan, E.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-05-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">442</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/1991JSV...146..439F"> <span id="translatedtitle">Orthogonality of <span class="hlt">wet</span> modes in coupled vibration</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The orthogonality property of <span class="hlt">wet</span> modes for arbitrary storage vessels filled or partially filled with compressible fluid is investigated by means of Love's thin shell equations and a linear potential flow theory. The proof shows that the <span class="hlt">wet</span> modes do possess the orthogonality property for all kinds of fluid-filled tanks with zero boundary energy conditions when incompressible fluid is considered and the effect of free surface waves is neglected. It is pointed out that there is another kind of orthogonality relationship among <span class="hlt">wet</span> modes when a compressible fluid is contained or (and) the effect of the free surface waves is considered.</p> <div class="credits"> <p class="dwt_author">Fang, Zhu</p> <p class="dwt_publisher"></p> <p class="publishDate">1991-05-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">443</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012APS..MAR.C1258G"> <span id="translatedtitle">Coefficient of restitution for <span class="hlt">wet</span> impacts</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">As the experience of playing football in the rain may tell, <span class="hlt">wetting</span> could influence the coefficient of restitution (COR) dramatically. This is due to the extra energy dissipation from the <span class="hlt">wetting</span> liquid, for instance viscous damping. To unveil the underlying mechanisms accounting for the influence, we study experimentally the COR by tracing free falling particles bouncing on a <span class="hlt">wet</span> surface. The dependance of the COR on the impact velocity, various particle and liquid properties will be presented and discussed in terms of dimensionless Stokes' and capillary numbers.</p> <div class="credits"> <p class="dwt_author">Gollwitzer, Frank; Huang, Kai; Krülle, Christof A.; Rehberg, Ingo</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-02-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">444</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/5231572"> <span id="translatedtitle">Asbestos/NESHAP adequately <span class="hlt">wet</span> guidance</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">The Asbestos NESHAP requires facility owners and/or operators involved in demolition and renovation activities to control emissions of particulate asbestos to the outside air because no safe concentration of airborne asbestos has ever been established. The primary method used to control asbestos emissions is to adequately <span class="hlt">wet</span> the Asbestos Containing Material (ACM) with a <span class="hlt">wetting</span> agent prior to, during and after demolition/renovation activities. The purpose of the document is to provide guidance to asbestos inspectors and the regulated community on how to determine if friable ACM is adequately <span class="hlt">wet</span> as required by the Asbestos NESHAP.</p> <div class="credits"> <p class="dwt_author">Shafer, R.; Throwe, S.; Salgado, O.; Garlow, C.; Hoerath, E.</p> <p class="dwt_publisher"></p> <p class="publishDate">1990-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">445</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/6591462"> <span id="translatedtitle">Dark <span class="hlt">matter</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">The evidence for the existence of dark <span class="hlt">matter</span> in the universe is reviewed; the different classes of particles proposed to account for the missing mass are briefly characterized; and the current status of efforts to detect these particles is surveyed. The emphasis is on the problem of Galactic dark <span class="hlt">matter</span> and its detection. Consideration is given to baryons, black holes, neutrinos, axions, and the weakly interacting massive particles predicted by supersymmetry models (photinos, higgsinos, zinos, and solar cosmions). 68 refs.</p> <div class="credits"> <p class="dwt_author">Spergel, D.N. (Texas Univ., Richardson (USA))</p> <p class="dwt_publisher"></p> <p class="publishDate">1989-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">446</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ia.usu.edu/viewproject.php?project=ia:7341"> <span id="translatedtitle">Measuring <span class="hlt">Matter</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">Use the links to help you complete each section. Make sure to record what you learn on the Measuring <span class="hlt">Matter</span> worksheet. 1. Read through the information found on the Measuring Mass website. Answer problems 1-3 and check your answers. Write the correct answers on the Measuring <span class="hlt">Matter</span> worksheet. Measuring Mass 2. Read through the information found on the Measuring Volume website. Calculate the volumes for Case I and Case II. Then, use the volume ...</p> <div class="credits"> <p class="dwt_author">Stewart, Mrs.</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-10-11</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">447</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2009AIPC.1145..837D"> <span id="translatedtitle">Fundamental relations between particle shape and the properties of <span class="hlt">granular</span> packings</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary"><span class="hlt">Granular</span> <span class="hlt">matter</span>, in its densely random packed state, is commonly found in numerous physical, biological and industrial systems. Improving our understanding of such packings has wide spread applicability, from simple issues of grain transportation, to large geological events such as landslides. We have studied the properties of dense jammed packings for an extensive range of three-dimensional particle shapes. We employ super-quadric particles, which allow us to vary the particle's aspect ratio, surface curvature and blockiness. We explore how the individual particle shape affects both the macroscopic and the local configurational properties of the system, smoothly transitioning from spherical particles possessing only translational degrees of freedom to large aspect ratio non-spherical grains where rotational degrees of freedom are highly important. Finally, we demonstrate how a fundamental understanding of the role of particle shape in <span class="hlt">granular</span> packings allows us to implement better communition models in DEM simulations, where particle breakage occurs and generates packings of fragments with realistic size and shape distributions.</p> <div class="credits"> <p class="dwt_author">Delaney, Gary W.; Cleary, Paul W.</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-06-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">448</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/23147869"> <span id="translatedtitle">Extraction of sediment-associated polycyclic aromatic hydrocarbons with <span class="hlt">granular</span> activated carbon.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Addition of activated carbon (AC) to sediments has been proposed as a method to reduce ecotoxicological risks of sediment-bound contaminants. The present study explores the effectiveness of <span class="hlt">granular</span> AC (GAC) in extracting polycyclic aromatic hydrocarbon (PAH) from highly contaminated sediments. Four candidate GAC materials were screened in terms of PAH extraction efficiency using single-step 24-h GAC extractions, with traditional 24-h Tenax extraction as a reference. Subsequently, sorption of native PAHs to the best performing GAC 1240W (0.45-1.70?mm) was studied for sediment only and for GAC-sediment mixtures at different GAC-sediment weight ratios, using 76-µm polyoxymethylene (POM) passive samplers. <span class="hlt">Granular</span> AC sorption parameters for PAHs were determined by subtracting the contribution of PAH sorption to sediment from PAH sorption to the GAC-sediment mixture. It appears that the binding of PAHs and the effectiveness of GAC to reduce sediment porewater concentrations were highly dependent on the GAC-sediment mixing ratio and hydrophobicity of the PAH. Despite the considerable fouling of GAC by organic <span class="hlt">matter</span> and oil, 50 to 90% of the most available PAH was extracted by the GAC during a 28-d contact time, at a dose as low as 4%, which also is a feasible dose in field-scale applications aimed at cleaning the sediment by GAC addition and removal. PMID:23147869</p> <div class="credits"> <p class="dwt_author">Rakowska, M I; Kupryianchyk, D; Grotenhuis, T; Rijnaarts, H H M; Koelmans, A A</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-12-27</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">449</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/23880431"> <span id="translatedtitle">Performance of an aerobic <span class="hlt">granular</span> sequencing batch reactor fed with wastewaters contaminated with Zn2+.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">The main aim of this study was to investigate the performance of an aerobic <span class="hlt">granular</span> sludge sequencing batch reactor (AGS-SBR) receiving water streams supplied with different loads of Zn(2+) (50 and 100 mg L(-1)) during an operation of 866 cycles (ca. 109 days). When the metal was not fed, chemical oxygen demand (COD), PO4(3-) and NH4(+) were efficiently removed, with efficiencies of 56, 23 and 72% respectively. DGGE profiles showed that Zn(2+) supply negatively affected the bacterial diversity and community structure of the granules. Consequently, the shock loadings with Zn(2+), particularly at the higher levels (100 mg L(-1)), affected the nutrient removal in the AGS-SBR, although the reactor still generally complied with admissible legal values concerning organic <span class="hlt">matter</span>, nitrogen and Zn. Simultaneous removal of PO4(3-) and TSS in such conditions needs further refining but the application of aerobic <span class="hlt">granular</span> SBR in the treatment of Zn(2+) contaminated wastewaters seems viable. PMID:23880431</p> <div class="credits"> <p class="dwt_author">Marques, Ana P G C; Duque, Anouk F; Bessa, Vânia S; Mesquita, Raquel B R; Rangel, António O S S; Castro, Paula M L</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-07-20</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">450</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2011PhRvL.107j8001T"> <span id="translatedtitle">Numerical Simulation of the Sedimentation of a Sphere in a Sheared <span class="hlt">Granular</span> Fluid: A <span class="hlt">Granular</span> Stokes Experiment</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We study, computationally, the sedimentation of a sphere of higher mass in a steady, gravity-driven <span class="hlt">granular</span> flow of otherwise identical spheres, on a rough inclined plane. Taking a hydrodynamic approach at the scale of the particle, we find the drag force to be given by a modified Stokes law and the buoyancy force by the Archimedes principle, with excluded volume effects taken into account. We also find significant differences between the hydrodynamic case and the <span class="hlt">granular</span> case, which are highlighted.</p> <div class="credits"> <p class="dwt_author">Tripathi, Anurag; Khakhar, D. V.</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-09-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">451</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/22067434"> <span id="translatedtitle">An optimization of allocation of information <span class="hlt">granularity</span> in the interpretation of data structures: toward <span class="hlt">granular</span> fuzzy clustering.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Clustering forms one of the most visible conceptual and algorithmic framework of developing information granules. In spite of the algorithm being used, the representation of information granules-clusters is predominantly numeric (coming in the form of prototypes, partition matrices, dendrograms, etc.). In this paper, we consider a concept of <span class="hlt">granular</span> prototypes that generalizes the numeric representation of the clusters and, in this way, helps capture more details about the data structure. By invoking the granulation-degranulation scheme, we design <span class="hlt">granular</span> prototypes being reflective of the structure of data to a higher extent than the representation that is provided by their numeric counterparts (prototypes). The design is formulated as an optimization problem, which is guided by the coverage criterion, meaning that we maximize the number of data for which their <span class="hlt">granular</span> realization includes the original data. The <span class="hlt">granularity</span> of the prototypes themselves is treated as an important design asset; hence, its allocation to the individual prototypes is optimized so that the coverage criterion becomes maximized. With this regard, several schemes of optimal allocation of information <span class="hlt">granularity</span> are investigated, where interval-valued prototypes are formed around the already produced numeric representatives. Experimental studies are provided in which the design of <span class="hlt">granular</span> prototypes of interval format is discussed and characterized. PMID:22067434</p> <div class="credits"> <p class="dwt_author">Pedrycz, Witold; Bargiela, Andrzej</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-11-03</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">452</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://eric.ed.gov/?q=%22physical+and+chemical+changes%22&id=EJ473501"> <span id="translatedtitle">Making and Experimenting with a <span class="hlt">Wet</span> Cell.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p class="result-summary">|Presents an activity that demonstrates the physical and chemical changes that occur during the operation of a <span class="hlt">wet</span> cell battery as it produces an electrical current. Provides instructions for the lesson. (MDH)|</p> <div class="credits"> <p class="dwt_author">George, Arnold</p> <p class="dwt_publisher"></p> <p class="publishDate">1993-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">453</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/1959"> <span id="translatedtitle"><span class="hlt">Wetting</span> of a Chemically Heterogeneous Surface</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Theories for inhomogeneous fluids have focused in recent years on <span class="hlt">wetting</span>, capillary conden- sation, and solvation forces for model systems where the surface(s) is(are) smooth homogeneous parallel plates, cylinders, or spherical drops. Unfortunately natural systems are more likely to be hetaogeneous both in surt%ce shape and surface chemistry. In this paper we discuss the conse- quences of chemical heterogeneity on <span class="hlt">wetting</span>. Specifically, a 2-dimensional implementation of a nonlocal density functional theory is solved for a striped surface model. Both the strength and range of the heterogeneity are varied. Contact angles are calculated, and phase transitions (both the <span class="hlt">wetting</span> transition and a local layering transition) are located. The <span class="hlt">wetting</span> properties of the surface ase shown to be strongly dependent on the nature of the surface heterogeneity. In addition highly ordered nanoscopic phases are found, and the operational limits for formation of ordered or crystalline phases of nanoscopic extent are discussed.</p> <div class="credits"> <p class="dwt_author">Frink, L.J.D.; Salinger, A.G.</p> <p class="dwt_publisher"></p> <p class="publishDate">1998-11-20</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">454</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/23736041"> <span id="translatedtitle"><span class="hlt">Wetting</span> on flexible hydrophilic pillar-arrays.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Dynamic <span class="hlt">wetting</span> on the flexible hydrophilic pillar-arrays is studied using large scale molecular dynamics simulations. For the first time, the combined effect of the surface topology, the intrinsic wettability and the elasticity of a solid on the <span class="hlt">wetting</span> process is taken into consideration. The direction-dependent dynamics of both liquid and pillars, especially at the moving contact line (MCL), is revealed at atomic level. The flexible pillars accelerate the liquid when the liquid approaches, and pin the liquid when the liquid passes. The liquid deforms the pillars, resulting energy dissipation at the MCL. Scaling analysis is performed based on molecular kinetic theory and validated by our simulations. Our results may expand our knowledge of <span class="hlt">wetting</span> on pillars and assisting the future design of active control of <span class="hlt">wetting</span> in practical applications. PMID:23736041</p> <div class="credits"> <p class="dwt_author">Yuan, Quanzi; Zhao, Ya-Pu</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">455</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013NatSR...3E1944Y"> <span id="translatedtitle"><span class="hlt">Wetting</span> on flexible hydrophilic pillar-arrays</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Dynamic <span class="hlt">wetting</span> on the flexible hydrophilic pillar-arrays is studied using large scale molecular dynamics simulations. For the first time, the combined effect of the surface topology, the intrinsic wettability and the elasticity of a solid on the <span class="hlt">wetting</span> process is taken into consideration. The direction-dependent dynamics of both liquid and pillars, especially at the moving contact line (MCL), is revealed at atomic level. The flexible pillars accelerate the liquid when the liquid approaches, and pin the liquid when the liquid passes. The liquid deforms the pillars, resulting energy dissipation at the MCL. Scaling analysis is performed based on molecular kinetic theory and validated by our simulations. Our results may expand our knowledge of <span class="hlt">wetting</span> on pillars and assisting the future design of active control of <span class="hlt">wetting</span> in practical applications.</p> <div class="credits"> <p class="dwt_author">Yuan, Quanzi; Zhao, Ya-Pu</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-06-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">456</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://oaspub.epa.gov/eims/eimsapi.dispdetail?deid=60364"> <span id="translatedtitle">A <span class="hlt">WET</span> TALE: TOXICITY OF COMPLEX EFFLUENTS</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p class="result-summary">This course covers standards, regulations, policy, guidance and technical aspects of implementing the whole effluent toxicity program. The curriculum incorporates rationale and information on <span class="hlt">WET</span> test requirements from USEPA documents, such as the Technical Support Document for W...</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">457</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ntis.gov/search/product.aspx?ABBR=AD772692"> <span id="translatedtitle">Theory of Metamorphism of <span class="hlt">Wet</span> Snow.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ntis.gov/search/index.aspx">National Technical Information Service (NTIS)</a></p> <p class="result-summary">Grain growth, bond growth and densification of <span class="hlt">wet</span> snow are described in terms of the distribution of equilibrium temperature in the snow matrix. At high water saturations the equilibrium temperature increases with grain size; hence, small particles melt ...</p> <div class="credits"> <p class="dwt_author">S. C. Colbeck</p> <p class="dwt_publisher"></p> <p class="publishDate">1973-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">458</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012LPICo1683.1143Q"> <span id="translatedtitle">MECA <span class="hlt">Wet</span> Chemistry: The Next Generation.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The NERNST project is focused on developing the next generation <span class="hlt">wet</span> chemistry laboratory based on techniques employed and lessons learned during the Mars Phoenix Microscopy, Electrochemistry, and Conductivity Analyzer (MECA) in situ experiments.</p> <div class="credits"> <p class="dwt_author">Quinn, R. C.; Aubrey, A. D.; Hecht, M. H.; Grunthaner, F. J.; Lee, M. C.; O'Neil, G. D.; DeFlores, L.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-10-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">459</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://hal.archives-ouvertes.fr/docs/00/25/49/20/PDF/ajp-jp4199707C1236.pdf"> <span id="translatedtitle"><span class="hlt">Wet</span> Chemistry of Spinel Iron oxide Particles</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Various properties of spinel iron oxide nanograins are reviewed, illustrating the broad possibilities of <span class="hlt">wet</span> chemistry for tailoring materials for a wide range of utilizations, fmm catalysis and sensors to cast magnetic materials.</p> <div class="credits"> <p class="dwt_author">J. P. Jolivet; C. Chan; P. Pren; E. Tronc</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">460</div> <div class="resultBody element"> <p class="result-title"><a target="resultT