The Josef UEF—a new location for “in-situ” physical modelling

2010 ◽  
pp. 305-310 ◽  
Keyword(s):  
Physical Modelling ◽  
New Location

scholarly journals Recent Advances in Ice Mechanics in Canada

1987 ◽  
Vol 40 (9) ◽  
pp. 1214-1231 ◽  
Author(s):  
N. K. Sinha ◽  
G. W. Timco ◽  
R. Frederking
Keyword(s):  
Physical Modelling ◽  
Field Studies ◽  
Material Structure ◽  
Naturally Occurring ◽  
Extensive Field ◽  
Strength And Deformation ◽  
Work Done ◽  
Ice Forces ◽  
Analytical Expressions

Work on the mechanics of ice, which has been carried forward on a broad front in Canada, has resulted in a number of significant advances in the last 10 years. The factors influencing the growth of various types of sea ice have been quantified fundamentally and methods for examining the resulting material structure have been developed. Extensive work has been done on strength and deformation characteristics of ice. A significant effort has been the development of analytical expressions to describe the rheological behavior of ice. Elastic modulus, Poisson’s ratio, and creep were also treated. A great deal has been done on measuring the compressive strength of various types of naturally occurring ice and subsequently these data were combined into a suitable description of a failure envelope. Work has also been done on measuring the flexural strength, shear strength, adhesion and fracture toughness. Methods for laboratory testing and in situ measurements of mechanical properties have been developed. The problem of defining ice forces on structures has been the primary motivation for research on ice. Analytical modelling, physical modelling, laboratory studies and very extensive field studies have been used. Work done in this area has included development of methods and their application to actual problems and has benefitted greatly from the integration of all four approaches. Very significant progress has been made. Ice and ice covers have been successfully used to support various offshore activities: drilling off floating ice platforms, stabilizing grounded rubble fields to protect structures and transporting large loads over ice.

Laboratory and In-Situ Testing and Physical Modelling of the Tailing Dump Capacity Increasing in a Mode of Operation

2016 ◽  
Author(s):  
Alan B. Lolaev ◽  
Aram P. Akopov ◽  
Aleksan Kh. Oganesian ◽  
Emil Kh. Oganesian ◽  
Giovana B. Georgetti
Keyword(s):  
Physical Modelling ◽  
In Situ Testing ◽  
Tailing Dump ◽  
Mode Of Operation

scholarly journals Selective biodegradation of keratin matrix in feather rachis reveals classic bioengineering

2009 ◽  
Vol 277 (1685) ◽  
pp. 1161-1168 ◽  
Author(s):  
Theagarten Lingham-Soliar ◽  
Richard H. C. Bonser ◽  
James Wesley-Smith
Keyword(s):  
Close Association ◽  
Three Dimensional ◽  
Elastic Recoil ◽  
Keratin Filaments ◽  
Microbial Biodegradation ◽  
Major Structural Component ◽  
First Time ◽  
Fibre Matrix ◽  
New Location

Flight necessitates that the feather rachis is extremely tough and light. Yet, the crucial filamentous hierarchy of the rachis is unknown—study hindered by the tight chemical bonding between the filaments and matrix. We used novel microbial biodegradation to delineate the fibres of the rachidial cortex in situ . It revealed the thickest keratin filaments known to date (factor >10), approximately 6 µm thick, extending predominantly axially but with a small outer circumferential component. Near-periodic thickened nodes of the fibres are staggered with those in adjacent fibres in two- and three-dimensional planes, creating a fibre–matrix texture with high attributes for crack stopping and resistance to transverse cutting. Close association of the fibre layer with the underlying ‘spongy’ medulloid pith indicates the potential for higher buckling loads and greater elastic recoil. Strikingly, the fibres are similar in dimensions and form to the free filaments of the feather vane and plumulaceous and embryonic down, the syncitial barbules, but, identified for the first time in 140+ years of study in a new location—as a major structural component of the rachis. Early in feather evolution, syncitial barbules were consolidated in a robust central rachis, definitively characterizing the avian lineage of keratin.

Plasticity of transposed rhombomeres: Hox gene induction is correlated with phenotypic modifications

Development ◽  
1995 ◽  
Vol 121 (9) ◽  
pp. 2707-2721 ◽  
Author(s):  
A. Grapin-Botton ◽  
M.A. Bonnin ◽  
L.A. McNaughton ◽  
R. Krumlauf ◽  
N.M. Le Douarin
Keyword(s):  
Gene Expression ◽  
Neural Tube ◽  
Hox Genes ◽  
Gene Expression Pattern ◽  
Fate Map ◽  
Hox Gene ◽  
Inductive Signal ◽  
New Location ◽  
Chick And Quail Embryos

In this study we have analysed the expression of Hoxb-4, Hoxb-1, Hoxa-3, Hoxb-3, Hoxa-4 and Hoxd-4 in the neural tube of chick and quail embryos after rhombomere (r) heterotopic transplantations within the rhombencephalic area. Grafting experiments were carried out at the 5-somite stage, i.e. before rhombomere boundaries are visible. They were preceeded by the establishment of the precise fate map of the rhombencephalon in order to determine the presumptive territory corresponding to each rhombomere. When a rhombomere is transplanted from a caudal to a more rostral position it expresses the same set of Hox genes as in situ. By contrast in many cases, if rhombomeres are transplanted from rostral to caudal their Hox gene expression pattern is modified. They express genes normally activated at the new location of the explant, as evidenced by unilateral grafting. This induction occurs whether transplantation is carried out before or after rhombomere boundary formation. Moreover, the fate of the cells of caudally transplanted rhombomeres is modified: the rhombencephalic nuclei in the graft develop according to the new location as shown for an r5/6 to r8 transplantation. Transplantation of 5 consecutive rhombomeres (i.e. r2 to r6), to the r8 level leads to the induction of Hoxb-4 in the two posteriormost rhombomeres but not in r2,3,4. Transplantations to more caudal regions (posterior to somite 3) result in some cases in the induction of Hoxb-4 in the whole transplant. Neither the mesoderm lateral to the graft nor the notochord is responsible for the induction. Thus, the inductive signal emanates from the neural tube itself, suggesting that planar signalling and predominance of posterior properties are involved in the patterning of the neural primordium.

A METHOD OF CAPTURING COLONIES OF AERIAL NESTING VESPID WASPS (HYMENOPTERA: VESPIDAE)

1983 ◽  
Vol 115 (4) ◽  
pp. 351-355
Author(s):  
M. J. Pallett ◽  
R. C. Plowright ◽  
D. L. Gibo
Keyword(s):  
Colony Development ◽  
Foraging Activity ◽  
Tunnel System ◽  
Adult Wasp ◽  
New Location

AbstractA method was developed for the transfer of intact medium-sized Dolichovespula arenaria colonies from their original locations, without damage to the nest and with minimal narcosis of the adult wasp population. The method necessitates a substantial manipulation early in the course of colony development, after which the nest is left to develop normally in situ until it is sufficiently populous to permit tranfer to a new location without intolerable loss of adult insects. We describe also a system for housing vespid colonies following relocation, together with a one-way tunnel system which has proved efficient for the purpose of collecting data on foraging activity.

Rendez vous with Saturn's rings

1984 ◽  
Vol 75 ◽  
pp. 743-759 ◽  
Author(s):  
Kerry T. Nock
Keyword(s):  
Solar Energy ◽  
Electric Propulsion ◽  
Power Source ◽  
Propulsion System ◽  
Low Thrust ◽  
Ring Plane ◽  
The Earth ◽  
Total Impulse ◽  
Saturn's Rings

ABSTRACTA mission to rendezvous with the rings of Saturn is studied with regard to science rationale and instrumentation and engineering feasibility and design. Future detailedin situexploration of the rings of Saturn will require spacecraft systems with enormous propulsive capability. NASA is currently studying the critical technologies for just such a system, called Nuclear Electric Propulsion (NEP). Electric propulsion is the only technology which can effectively provide the required total impulse for this demanding mission. Furthermore, the power source must be nuclear because the solar energy reaching Saturn is only 1% of that at the Earth. An important aspect of this mission is the ability of the low thrust propulsion system to continuously boost the spacecraft above the ring plane as it spirals in toward Saturn, thus enabling scientific measurements of ring particles from only a few kilometers.

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