236,423 research outputs found
Exact analytical solution of viscous Korteweg-deVries equation for water waves
The evolution of a solitary wave with very weak nonlinearity which was
originally investigated by Miles [4] is revisited. The solution for a
one-dimensional gravity wave in a water of uniform depth is considered. This
leads to finding the solution to a Korteweg-de Vries (KdV) equation in which
the nonlinear term is small. Also considered is the asymptotic solution of the
linearized KdV equation both analytically and numerically. As in Miles [4], the
asymptotic solution of the KdV equation for both linear and weakly nonlinear
case is found using the method of inversescattering theory. Additionally
investigated is the analytical solution of viscous-KdV equation which reveals
the formation of the Peregrine soliton that decays to the initial sech^2(\xi)
soliton and eventually growing back to a narrower and higher amplitude
bifurcated Peregrine-type soliton.Comment: 15 page
Geological applications of LANDSAT-1 imagery to the Great Salt Lake area
The ERTS program has been designed as a research and development tool to demonstrate that remote sensing from orbital altitudes is a feasible and practical approach to efficient management of earth resources. From this synoptic view and repetitive coverage provided by ERTS imagery of the Great Salt Lake area, large geological and structural features, trends, and patterns have been identified and mapped. A comparative analysis of lineaments observed in September and December data was conducted, existing mineral locations were plotted, and areas considered prospective for mineralization based on apparent structure-mineralization relationships were defined. The additional information obtained using ERTS data provides an added source of information to aid in the development of more effective mineral exploration programs
Economical technique for fragmentation testing
Automatic rifle was modified for remote, single-shot use. To simulate statistically--determined fragment size from rocket-motor casing blunt-nosed bullet was made of same alloy. Cartridge was loaded with enough powder to make bullet reach target at same estimated velocity as shrapnel from rocket casing
Proposed Spontaneous Generation of Magnetic Fields by Curved Layers of a Chiral Superconductor
We demonstrate that two-dimensional chiral superconductors on curved surfaces
spontaneously develop magnetic flux. This geometric Meissner effect provides an
unequivocal signature of chiral super- conductivity, which could be observed in
layered materials under stress. We also employ the effect to explain some
puzzling questions related to the location of zero-energy Majorana modes
Dynamic characteristics of single crystal SSME blades
The Space Shuttle Main Engine (SSME) High Pressure Fuel Turbopump (HPFTP) blades are currently manufactured using a directionally solidified (DS) material, MAR-M-246+Hf. However, a necessity to reduce the occurrence of fatigue cracking within the DS blades has lead to an interest in the use of a single crystal (SC) material, PWA-1480. A study was initiated to determine the dynamic characteristics of the HPFTP blades made of SC material and find possible critical engine order excitations. This study examined both the first and second stage drive turbine blades of the HPFTP. The dynamic characterization was done analytically as well as experimentally. The analytical study examined the SC first stage HPFTP blade dynamic characteristics under typical operating conditions. The blades were analyzed using MSC/NASTRAN and a finite element model. Two operating conditions, 27500 RPM and 35000 RPM, were investigated
Tests on Built-Up Airplane Struts Having Initial Tension in Outside Fibers
The conventional airplane strut fails by buckling. The first signs of failure usually are compression cracks on the concave side of bending. It would therefore appear that if an initial tension could be introduced in the outside fibers, this tension would have to be relieved before the compression load could make itself felt
Pulmonary artery smooth muscle cells response to vaso-active stimulations in a real-time 3-Dimensional model
INTRODUCTION: The tone of the pulmonary arteries is the summation of the activity of each smooth muscle cell (PASMC) within a vessel wall and its interaction with the endothelial cells and extracellular matrix (including collagen). There are reported phenotypic differences between PASMC in the inner & outer layers of pulmonary artery walls1. The response of a tissue engineered blood vessel to contractile and relaxing stimulants in-vitro is essential to predicting the response of the physiological and pathological vessels in-vivo. Previous work showed that pulmonary artery relaxation to nitric oxide is inhibited after exposure to chronic hypoxia 2. We hypothesised that PASMC will differ in their ability to contract or relax a 3D collagen gel. Using a Culture Force Monitor (CFM) we sought to quantify the cellular response of PASMC derived from inner and outer normal and hypoxic arteries, harvested from piglet models, over 24 hours in response to contractile agonists and relaxing antagonists
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