Second-order nearly orthogonal Latin hypercubes for exploring stochastic simulations

2017 ◽  
Vol 11 (2) ◽  
pp. 137-150 ◽  
Author(s):  
A D MacCalman ◽  
H Vieira ◽  
T Lucas
Keyword(s):  
Second Order ◽  
Stochastic Simulations ◽  
Latin Hypercubes

Observations and Modeling of Linear and Nonlinear Spatio-Temporal Wave Statistics

2010 ◽  
Author(s):  
Leonel Romero ◽  
W. Kendall Melville
Keyword(s):  
Spatial Information ◽  
Second Order ◽  
Stochastic Simulations ◽  
Ocean Engineering ◽  
Engineering Applications ◽  
Large Wave ◽  
Wave Statistics ◽  
Wave Parameters ◽  
Wave Heights ◽  
Spatio Temporal

We present an analysis of airborne wave observations collected in the Gulf of Tehuantepec. The data includes LIDAR measurements of the surface displacement as a function of two horizontal dimensions and time in fetch-limited conditions, with fetches between 50 and 300 km and winds between 10 and 20 m/s. The spatio-temporal data have an advantage over the commonly used single point time-series measurements allowing direct estimates of the wavelength and wave slope, including spatial information such as the lengths of crests exceeding threshold wave heights and slopes. The statistics of these wave parameters are particularly important for risk assessment of off-shore structures and in other ocean engineering applications. We present an analysis of several statistical wind-wave parameters, including the joint probability distribution function (pdf) of wave amplitudes and wavelengths, the pdf of wave heights, wavenumber vectors, and wave slopes, including the statistics of crests lengths exceeding threshold wave heights or slopes. The empirical findings from the LIDAR data are related to the analytical work by Longuet-Higgins (1957) [1] for a linear spectrum, including the average length of contours surrounding large wave heights. The effect of second-order nonlinearities on the distribution of crest lengths is investigated with numerical stochastic simulations from computed directional wavenumber spectra. The results show that second-order nonlinearities can increase the crest length density of large waves by about a factor of two or more. The results are discussed in the context of predicting wave statistics for ocean engineering applications.

Disappearance Voltage Determinations Using a Convergent Beam

1971 ◽  
Vol 29 ◽  
pp. 184-185
Author(s):  
W. L. Bell
Keyword(s):  
Second Order ◽  
Objective Method ◽  
Uniform Thickness ◽  
Rocking Curve ◽  
Crystal Perfection ◽  
Kikuchi Line ◽  
Central Maximum ◽  
Diffraction Patterns ◽  
Convergent Beam ◽  
Beam Technique

Disappearance voltages for second order reflections can be determined experimentally in a variety of ways. The more subjective methods, such as Kikuchi line disappearance and bend contour imaging, involve comparing a series of diffraction patterns or micrographs taken at intervals throughout the disappearance range and selecting that voltage which gives the strongest disappearance effect. The estimated accuracies of these methods are both to within 10 kV, or about 2-4%, of the true disappearance voltage, which is quite sufficient for using these voltages in further calculations. However, it is the necessity of determining this information by comparisons of exposed plates rather than while operating the microscope that detracts from the immediate usefulness of these methods if there is reason to perform experiments at an unknown disappearance voltage.The convergent beam technique for determining the disappearance voltage has been found to be a highly objective method when it is applicable, i.e. when reasonable crystal perfection exists and an area of uniform thickness can be found. The criterion for determining this voltage is that the central maximum disappear from the rocking curve for the second order spot.

Second order interference in two photon absorption

1996 ◽  
Vol 43 (9) ◽  
pp. 1765-1771 ◽  
Author(s):  
M. W. HAMILTON and D. S. ELLIOTT
Keyword(s):  
Second Order ◽  
Photon Absorption ◽  
Two Photon Absorption ◽  
Two Photon
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