Oil-based critical mud weight window analyses in HTHP fractured tight formation

A swarm of autonomous underwater vehicles can be a valuable alternative for fully equipped and very expensive super-vehicles. A distributed system of tightly cooperating vehicles can be cheaper, simpler in maintenance, more reliable, more flexible and universal than traditional single-vehicle systems. However, keeping a tight formation of underwater vehicles in the condition of the sea current, unclear environment, and rare inter-vehicle communication is a very challenging problem, which requires an effective vehicle control system. The paper proposes a solution to the above-mentioned problem, which is based on neuro-evolution. Moreover, the paper also presents the first results of the proposed system.

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The junctional complex in the intestine of Sagitta setosa (Chaetognatha): the paired septate junction

Journal of Cell Science ◽

10.1242/jcs.42.1.227 ◽

1980 ◽

Vol 42 (1) ◽

pp. 227-246

Author(s):

M. Duvert ◽

D. Gros ◽

C. Salat

Keyword(s):

Uranyl Acetate ◽

The Other ◽

Septate Junction ◽

Junctional Complex ◽

Outer Diameter ◽

Central Ring ◽

Straight Path ◽

New Type ◽

Pleated Sheet ◽

Tight Formation

The junctional complex of the intestine of Sagitta setosa has been studied in tissues stained with uranyl acetate or after lanthanum impregnation, and by freeze-cleavage. All types of junctions have been characterized in both perpendicular and tangential planes. From the apex to the base of the cell the following junctions occur in this order: a zonula adhaerens; a septate junction where the septa occur in pairs; a pleated sheet septate junction; and numerous gap junctions of the A-type. From the upper part of the cells inwards to the septate junction, the membranes follow a relatively straight path. In the lower part of the cells the membranes are deeply interdigitating. At the intersection between 3 cells a very different junction is to be observed where small units, periodically disposed, bind the membranes of the 3 adjoining cells. Each unit is composed of 3 short segments which bind the cell membranes to a central ring 16.6 +/− 2.3 nm in outer diameter. The paired septate junction constitutes a new type. Its main features are that the septa are paired and occur in 2 formations, one the ‘loose formation’, with elements between the septa of each pair, and the other, a ‘tight formation’. After lanthanum impregnation, the thickness of each septum is seen to be about 3 nm and the undulation period 12.6 +/− 1.6 nm. On freeze-fractures 10-nm particles are found on crests on the PF face and in furrows on the EF face. The possible significance of this type of junction is discussed. The junctional complex described is analogous to those found in various invertebrate epithelia.

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Large Weapons, Small Greeks: The Practical Limitations of Hoplite Weapons and Equipment

Men of Bronze ◽

10.23943/princeton/9780691143019.003.0008 ◽

2013 ◽

Cited By ~ 1

Author(s):

Adam Schwartz

Keyword(s):

Detailed Analysis ◽

Surface Area ◽

Original Design ◽

Sheer Size ◽

Tight Formation

This chapter argues that the defining elements of the hoplite were the spear and, above all, the double-grip shield. Other items of the panoply were subject to much change and innovation over the centuries, but the shield and spear remained essentially unaltered throughout the entire hoplite era. This chapter reasons that the Greeks maintained the shield's original design—circular, concave, and about one meter in diameter—because it was preeminently suited for a specific purpose, fighting in tight formation in a phalanx. It gives a detailed analysis of the Etruscan Bomarzo shield, one of the few hoplite type shields to survive more or less intact from antiquity, and assesses a number of key sources bearing out the burden and cumbersomeness of the hoplite shield, to conclude that its weight, shape, and sheer size in terms of surface area made the shield particularly unwieldy.

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