37,204 research outputs found
Turbulence and turbulent mixing in natural fluids
Turbulence and turbulent mixing in natural fluids begins with big bang
turbulence powered by spinning combustible combinations of Planck particles and
Planck antiparticles. Particle prograde accretions on a spinning pair releases
42% of the particle rest mass energy to produce more fuel for turbulent
combustion. Negative viscous stresses and negative turbulence stresses work
against gravity, extracting mass-energy and space-time from the vacuum.
Turbulence mixes cooling temperatures until strong-force viscous stresses
freeze out turbulent mixing patterns as the first fossil turbulence. Cosmic
microwave background temperature anisotropies show big bang turbulence fossils
along with fossils of weak plasma turbulence triggered as plasma photon-viscous
forces permit gravitational fragmentation on supercluster to galaxy mass
scales. Turbulent morphologies and viscous-turbulent lengths appear as linear
gas-proto-galaxy-clusters in the Hubble ultra-deep-field at z~7. Proto-galaxies
fragment into Jeans-mass-clumps of primordial-gas-planets at decoupling: the
dark matter of galaxies. Shortly after the plasma to gas transition,
planet-mergers produce stars that explode on overfeeding to fertilize and
distribute the first life.Comment: 23 pages 12 figures, Turbulent Mixing and Beyond 2009 International
Center for Theoretical Physics conference, Trieste, Italy. Revision according
to Referee comments. Accepted for Physica Scripta Topical Issue to be
published in 201
Litter on Wheels: An Ocean Garbage Art Car
In the Fall term of 2018, Gettysburg College seniors Bill LeConey and Will Gibson created the world\u27s first Ocean Garbage Art Car, by covering an old Ford truck with plastic bottles (and other trash commonly found in our oceans), to raise awareness about anthropogenic pollution in our seas. Since the 1950’s, plastics have been an essential and ubiquitous commodity in nearly every society on the planet. Plastics find their way into just about every aspect of our lives - from water bottles and cell phone cases, to even advanced medical equipment and space shuttles - it’s no secret how prevalent plastic is. Unfortunately, an overwhelming majority of the ≈450 million tons of plastic produced annually ends up in our oceans, posing a substantial threat to our aquatic life and the ecosystems they reside in. Much of this waste coalesces into gyres called garbage patches - some as large as countries - floating within the water column, and harming the tranquility of the environment they are intruding on. Several environmental art forms similar to our Ocean Garbage Art Car were studied and compared to give a more in depth background on our issue. Many other artists have utilized ocean trash, but ours is a one of a kind. An urgent call to action must take place to cleanup our oceans and to stop the excessive waste of plastic before irreversible repercussions occur. It is our hope that the Ocean Garbage Art Car created in the ES 400 seminar will help raise awareness about this dire issue threatening our planet as we know it
Higher-order compatible finite element schemes for the nonlinear rotating shallow water equations on the sphere
We describe a compatible finite element discretisation for the shallow water
equations on the rotating sphere, concentrating on integrating consistent
upwind stabilisation into the framework. Although the prognostic variables are
velocity and layer depth, the discretisation has a diagnostic potential
vorticity that satisfies a stable upwinded advection equation through a
Taylor-Galerkin scheme; this provides a mechanism for dissipating enstrophy at
the gridscale whilst retaining optimal order consistency. We also use upwind
discontinuous Galerkin schemes for the transport of layer depth. These
transport schemes are incorporated into a semi-implicit formulation that is
facilitated by a hybridisation method for solving the resulting mixed Helmholtz
equation. We illustrate our discretisation with some standard rotating sphere
test problems.Comment: accepted versio
The natural bacterial agglutinins
1. A study has been made of natural agglutination as exemplified by the reactions of the serum of nine animal species with a variety of bacteria.2. End-titres are recorded, and the fact is noted that sera of different animal species show an order of agglutinating activity which is almost constant for all organisms used. Ox, pig and horse sera give consist - :ently strong reactions, while specimens from rabbit, guinea -pig and rat react weakly or not at all. Sheep, human and cat sera occupy an intermediate position. Variations are noted, however, with different individual specimens of serum from the same species.3. Organisms of the series tested can also be grouped in order according to their apparent susceptibility to agglutination by normal sera.4. The serum of young animals is found to be deficient in the agglutinating principle.5. The agglutinating effect shows a thermolability intermediate between that of complement and the immune agglutinins. Complete inactivation occurs as a rule after exposure to 60 °C. - 65 °C. for half -an -hour. For certain strains the serum principle is inactivated at much lower temperatures.6. Lability curves show marked irregularity. In certain cases a zone of relative inactivation is produced at a temperature of 55 °C.7. The natural agglutinating substance is found to be present in greater degree in the carbonic acid in- :soluble fraction of serum than in the carbonic acid soluble fraction, In this respect it differs from the immune agglutinins, which are chiefly located in the carbonic acid soluble moiety.8. The agglutinating principle for each organism can be absorbed completely by the homologous strain, when a variable lowering of the end -titre for other unrelated organisms results. A similar lowering of activity for these organisms may be produced by treating the serum with non -specific physical absorbents. Charcoal and Kieselguhr were used to demonstrate this.9. By the technique of double absorption it can be shown that agglutination depends on non-specific and specific factors and it is concluded that normal serum agglutinates bacteria in virtue of a twofold mechanism: (a) A non-specific effect reacting in varying degree with all organisms and removable by treatment with a finely divided absorbent. (b) A series of specific effects reacting as true "natural antibodies ". These specific antibody -like principles exist for a wide variety of organisms. Absorption of any one organism removes the homologous effect leaving the remainder quantitatively unimpaired.10. Normal serum from various mammalian animals contains agglutinins which react with the "H" and "0" antigenic constituents of motile bacteria. Flagellar suspensions have been used to demonstrate H- agglutinins.11. Agglutinin- absorption experiments show that the specificity of natural agglutinins depends chiefly on the "H" type. The "0" type agglutinins appear to possess affinities for antigenic constituents which are more widely shared by different organisms.12. It was not found possible to demonstrate the antigenic relationship among members of the Salmonella and B. proteus X groups so precisely with normal sera as with immune sera.13. The thermolability of the 0- agglutinins was found to be greater than that of the "H" type in the normal serum of a number of animal species. Both showed greater lability than the corresponding immune agglutinins.14. "Rough" and "smooth" variants of the same bacterial strain showed antigenic differences in their reactions with normal sera.15. The origin of natural agglutinins is discussed in its relation to other natural immunity reactions.16. The suggestion is made that true natural antibodies must be contrasted with specific immune anti- bodies in the serum of apparently normal animals. .After reviewing the available evidence, the conclusion is reached that the former cannot be regarded as a response to a specific stimulus. The most satisfactory explanation of their presence is one which suggests that they arise spontaneously in the course of the serological development of the animal
A real-time digital computer program for the simulation of a single rotor helicopter
A computer program was developed for the study of a single-rotor helicopter on the Langley Research Center real-time digital simulation system. Descriptions of helicopter equations and data, program subroutines (including flow charts and listings), real-time simulation system routines, and program operation are included. Program usage is illustrated by standard check cases and a representative flight case
Gravitational hydrodynamics of large scale structure formation
The gravitational hydrodynamics of the primordial plasma with neutrino hot
dark matter is considered as a challenge to the bottom-up cold dark matter
paradigm. Viscosity and turbulence induce a top-down fragmentation scenario
before and at decoupling. The first step is the creation of voids in the
plasma, which expand to 37 Mpc on the average now. The remaining matter clumps
turn into galaxy clusters. Turbulence produced at expanding void boundaries
causes a linear morphology of 3 kpc fragmenting protogalaxies along vortex
lines. At decoupling galaxies and proto-globular star clusters arise; the
latter constitute the galactic dark matter halos and consist themselves of
earth-mass H-He planets. Frozen planets are observed in microlensing and
white-dwarf-heated ones in planetary nebulae. The approach also explains the
Tully-Fisher and Faber-Jackson relations, and cosmic microwave temperature
fluctuations of micro-Kelvins.Comment: 6 pages, no figure
Post-processing partitions to identify domains of modularity optimization
We introduce the Convex Hull of Admissible Modularity Partitions (CHAMP)
algorithm to prune and prioritize different network community structures
identified across multiple runs of possibly various computational heuristics.
Given a set of partitions, CHAMP identifies the domain of modularity
optimization for each partition ---i.e., the parameter-space domain where it
has the largest modularity relative to the input set---discarding partitions
with empty domains to obtain the subset of partitions that are "admissible"
candidate community structures that remain potentially optimal over indicated
parameter domains. Importantly, CHAMP can be used for multi-dimensional
parameter spaces, such as those for multilayer networks where one includes a
resolution parameter and interlayer coupling. Using the results from CHAMP, a
user can more appropriately select robust community structures by observing the
sizes of domains of optimization and the pairwise comparisons between
partitions in the admissible subset. We demonstrate the utility of CHAMP with
several example networks. In these examples, CHAMP focuses attention onto
pruned subsets of admissible partitions that are 20-to-1785 times smaller than
the sets of unique partitions obtained by community detection heuristics that
were input into CHAMP.Comment: http://www.mdpi.com/1999-4893/10/3/9
Vortex-type elastic structured media and dynamic shielding
The paper addresses a novel model of metamaterial structure. A system of
spinners has been embedded into a two-dimensional periodic lattice system. The
equations of motion of spinners are used to derive the expression for the
chiral term in the equations describing the dynamics of the lattice. Dispersion
of elastic waves is shown to possess innovative filtering and polarization
properties induced by the vortextype nature of the structured media. The
related homogenised effective behavior is obtained analytically and it has been
implemented to build a shielding cloak around an obstacle. Analytical work is
accompanied by numerical illustrations.Comment: 24 pages, 13 figure
Communicative success in spatial dialogue: The impact of functional features and dialogue strategies
This paper addresses the impact of dialogue strategies and functional features of spatial arrangements on communicative success. To examine the sharing of cognition between two minds in order to achieve a joint goal, we collected a corpus of 24 extended German-language dialogues in a referential communication task that involved furnishing a dolls’ house. Results show how successful communication, as evidenced by correct placement of furniture items, is affected by a) functionality of the furniture arrangement, b) previous task experience, and c) dialogue features such as description length and orientation information. To enhance research in this area, our 'Dolldialogue' corpus is now available as a free resource on www.dolldialogue.spac
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