Dynamics of sand-piles games on graphs

2005 ◽  
pp. 219-230 ◽  
Author(s):  
Eric Goles ◽  
Marcos A. Kiwi
Keyword(s):  
Games On Graphs ◽  
Sand Piles

The Scanning Electron Microscopic Observation of the Vestibular Sensory Epithelia

1969 ◽  
Vol 27 ◽  
pp. 40-41
Author(s):  
D.J. Lim ◽  
W.C. Lane
Keyword(s):  
Semicircular Canals ◽  
Electron Microscopic Observation ◽  
Gravitational Acceleration ◽  
Electron Microscopic ◽  
Sensory Epithelia ◽  
Scanning Electron Microscopic ◽  
Vestibular Sensory Epithelia ◽  
And Function ◽  
Sand Piles ◽  
Active Investigation

The morphology and function of the vestibular sensory organs has been extensively studied during the last decade with the advent of electron microscopy and electrophysiology. The opening of the space age also accelerated active investigation in this area, since this organ is responsible for the sensation of balance and of linear, angular and gravitational acceleration.The vestibular sense organs are formed by the saccule, utricle and three ampullae of the semicircular canals. The maculae (sacculi and utriculi) have otolithic membranes on the top of the sensory epithelia. The otolithic membrane is formed by a layer of thick gelatin and sand-piles of calcium carbonate crystals (Fig.l).

New Method for In-Trench Pipeline Support

2012 ◽  
Author(s):  
Geoff W. Connors
Keyword(s):  
Cathodic Protection ◽  
Welding Process ◽  
High Strength ◽  
Test Water ◽  
Poly Type ◽  
Additional Protection ◽  
Injection Molded ◽  
Heavy Loads ◽  
Sand Piles

Protection of the pipe during and after pipeline construction is of paramount importance for safety and pipeline integrity. Areas of rock and stone are often encountered during construction of new pipelines. Even with modern pipeline coatings, additional protection for the pipe is necessary where rock or stone exposure is significant. Historically, additional pipe protection used in these types of situations is achieved through adding either a significant layer of sand or select backfill above and below the pipeline (sand padding) and/or by attaching a high-impact resistant, poly-type rock shield around the pipeline during the pipeline installation process. To accommodate sand padding, some form of intermittent support of the pipeline is generally required to elevate the pipeline off the trench bottom. Similar intermittent support is also recommended practice when using poly-type rock shields to keep the pipeline from fully resting on trench rocks. Current methods of in-trench support involve sand piles, sand bags, spray foam and individually formed foam pillows — each with drawbacks: i) Sand Piles are difficult to install and often oval or dent the pipe when improperly placed. ii) Sand bags require hand placement for proper support. In open trenches, this can be time consuming and unsafe. Improper placement can cause the pipe to oval or dent. iii) Spray-in foam is considered to be an obstruction of cathodic protection currents. Newly constructed pipelines full of hydrostatic test water and one metre cover can cause foam to compress excessively. iv) Foam pillows are light and easily placed — but can float out of position and compress or crack under heavy loads. As with all foam, cathodic shielding is always a concern. A new, engineered method of in-trench pipeline support is now available — the Structured Pipeline Pillow (SPP). SPP’s are injection molded and made from high strength, environmentally inert polypropylene or polyethylene resins. Designed to support any size pipeline, SPP’s are most effective with larger diameter, heavier pipelines. One SPP is engineered to carry a single 40′ joint of heavy wall pipeline filled with hydrostatic test water. Compared with current methods, SPP’s: i) Stack tightly for transport. ii) Are light enough for installation from outside the trench and resist floatation when ground water is present. iii) Help ensure the pipeline is centered in the trench during the pipeline installation. iv) Maintain long-term pipe clearance above rocky trench bottoms. v) Ovality and denting concerns are reduced. vi) Allow cathodic protection an easy path to the pipeline. vii) Will never biodegrade. In their extended stacking mode, SPP’s tested well as an effective alternative to wooden skids for many situations such as pipe stockpiling; stringing along the rights-of-way (ROW); and even for some low level skidding during the welding process.

On the modelling of real sand piles

1992 ◽  
Vol 182 (3) ◽  
pp. 295-319 ◽  
Author(s):  
H. Puhl
Keyword(s):  
Sand Piles

Related Games on Graphs and Hypergraphs

2021 ◽  
pp. 83-108
Author(s):  
Boštjan Brešar ◽  
Michael A. Henning ◽  
Sandi Klavžar ◽  
Douglas F. Rall
Keyword(s):  
Games On Graphs

Fugitive-search games on graphs and related parameters

1995 ◽  
pp. 331-342 ◽  
Author(s):  
Nick D. Dendris ◽  
Lefteris M. Kirousis ◽  
Dimitris M. Thilikos
Keyword(s):  
Search Games ◽  
Games On Graphs

MULTIFRACTAL STRUCTURE IN SAND DRAWINGS

Fractals ◽  
2020 ◽  
Vol 28 (01) ◽  
pp. 2050004 ◽  
Author(s):  
R. E. MOCTEZUMA ◽  
JORGE GONZÁLEZ-GUTIÉRREZ
Keyword(s):  
Visual Art ◽  
Structural Complexity ◽  
Intangible Cultural Heritage ◽  
Self Similarity ◽  
Abstract Expressionist ◽  
Natural Landscapes ◽  
Human Figure ◽  
Self Similar ◽  
Sand Piles ◽  
Elaboration Process

The construction of an abstract expressionist artwork is driven by chaotic mechanisms that sculpt multifractal characteristics. Jackson Pollock’s paintings, for example, arise due to the random process of depositing drops and jets of paint on a canvas. However, most of the paintings and drawings try to recreate with fidelity common forms, natural landscapes, and the human figure. Accordingly, in the context of the formation of statistically self-similar objects, a question persists: will it be possible to find some vestige of multifractal structure in drawings or paintings whose elaboration process tries to avoid chaos? In this work, we scrutinize into several artistic drawings in sand to answer this intriguing question. These pieces of art are elaborated using craters, furrows, and sand piles; and some of them are inscribed on the Representative List of the Intangible Cultural Heritage of Humanity. We prove that the sand drawings analyzed here are multifractal objects. This finding suggests that a piece of visual art, which may initially appear ordered, contains many components distributed at different degrees of self-similarity that substantially increase the structural complexity.

scholarly journals The complexity of flood-filling games on graphs

2012 ◽  
Vol 160 (7-8) ◽  
pp. 959-969 ◽  
Author(s):  
Kitty Meeks ◽  
Alexander Scott
Keyword(s):  
Games On Graphs
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