scholarly journals RESONANCES OF COASTAL WATERS BETWEEN PERTH AND GERALDTON (WESTERN AUSTRALIA)

1980 ◽  
Vol 1 (17) ◽  
pp. 16 ◽  
Author(s):  
H. Allison ◽  
A. Grassia ◽  
R. Litchfield
Keyword(s):  
Spectral Analysis ◽  
Coastal Waters ◽  
Statistical Estimation ◽  
Model Comparison ◽  
Two Dimensional ◽  
Resonance Frequencies ◽  
Sea Level Oscillations ◽  
Near Shore ◽  
Quality Factor Q ◽  
Western Australian

Sea-level oscillations along the Western Australian coast, with periods in the range of 20-40 mins, have considerably greater amplitudes between Perth and Geraldton than at other locations along the coastline. It is shown that amplification of these oscillations is due to resonance in the near shore basin formed by the shore and a submerged reef-chain parallel to and 5 km from the shore. The rigorous analytical solution for the resonance frequencies is obtained for the two-dimensional hydrodynamic model. Comparison with results from spectral analysis of recorded oscillations indicates a satisfactorily agreement with the theory. Statistical estimation of damping of the observed oscillations indicates that the predominant resonance in the first mode is sharp, having the quality factor Q=10.

Sporadic Sea-level Oscillations along the Western Australian Coastline

1979 ◽  
Vol 30 (6) ◽  
pp. 723 ◽  
Author(s):  
H Allison ◽  
A Grassia
Keyword(s):  
Sea Level ◽  
Amplification Factor ◽  
Average Distance ◽  
Predominant Period ◽  
Oscillation Energy ◽  
Sea Level Oscillations ◽  
Near Shore ◽  
Australian Coastline ◽  
Hemisphere Winter ◽  
Western Australian

Sporadic sea-level oscillations were recorded on the Western Australian continental shelf. The largest oscillations with amplitudes up to 50 cm occur on the shelf between Perth and Geraldton. It is shown that magnification of the oscillation in this area is caused by resonance in a near-shore channel, formed by the shore and a submerged reef-chain parallel to the shore at an average distance of 5500 m offshore. The estimated resonance amplification factor is about 10. Predominant period of oscillations is about 30 min. Statistical analysis of the oscillations during the period between 1963 and 1978 indicated a significant correlation with solar activity. Seasonal variations in oscillation energy were found to have a significant peak during Southern Hemisphere winter months, when storms in the Indian and Southern Oceans are more frequent. This supports the hypothesis that the near-shore oscillations observed have the same 'excitation- from-the-ocean' resonance mechanism as that established by Miles and Munk for harbours.

scholarly journals On the generation of internal waves by river plumes in subcritical initial conditions

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
R. Mendes ◽  
J. C. B. da Silva ◽  
J. M. Magalhaes ◽  
B. St-Denis ◽  
D. Bourgault ◽  
...  
Keyword(s):  
Numerical Modeling ◽  
Internal Waves ◽  
Coastal Waters ◽  
Initial Conditions ◽  
Spatial Scales ◽  
River Plumes ◽  
Wide Range ◽  
Near Shore ◽  
Generation Mechanisms ◽  
Douro River

AbstractInternal waves (IWs) in the ocean span across a wide range of time and spatial scales and are now acknowledged as important sources of turbulence and mixing, with the largest observations having 200 m in amplitude and vertical velocities close to 0.5 m s−1. Their origin is mostly tidal, but an increasing number of non-tidal generation mechanisms have also been observed. For instance, river plumes provide horizontally propagating density fronts, which were observed to generate IWs when transitioning from supercritical to subcritical flow. In this study, satellite imagery and autonomous underwater measurements are combined with numerical modeling to investigate IW generation from an initial subcritical density front originating at the Douro River plume (western Iberian coast). These unprecedented results may have important implications in near-shore dynamics since that suggest that rivers of moderate flow may play an important role in IW generation between fresh riverine and coastal waters.

Temperature dependence of nuclear resonance frequencies in the two-dimensional ferromagnet K2CuF4

1973 ◽  
Vol 43 (1) ◽  
pp. 39-41 ◽  
Author(s):  
Le Dang Khoi ◽  
P. Veillet ◽  
J-P. Renard ◽  
C. Jacoboni
Keyword(s):  
Temperature Dependence ◽  
Nuclear Resonance ◽  
Two Dimensional ◽  
Resonance Frequencies

scholarly journals On the detection of corrosion pit interactions using two-dimensional spectral analysis

2010 ◽  
Vol 52 (2) ◽  
pp. 303-313 ◽  
Author(s):  
Adil Jarrah ◽  
Jean-Marie Nianga ◽  
Alain Iost ◽  
Gildas Guillemot ◽  
Denis Najjar
Keyword(s):  
Spectral Analysis ◽  
Two Dimensional ◽  
Corrosion Pit

Plasmonic excitations in two-dimensional materials: effects of structural symmetry and material anisotropy

2022 ◽  
Author(s):  
Linhui Ding ◽  
Ningning Wang ◽  
Leiming Chen ◽  
Kui Han ◽  
Xiaopeng Shen ◽  
...  
Keyword(s):  
Noble Metals ◽  
Higher Order ◽  
Two Dimensional ◽  
Material Anisotropy ◽  
Structural Symmetry ◽  
Dipole Resonance ◽  
Higher Order Modes ◽  
Resonance Frequencies ◽  
Two Dimensional Materials ◽  
Two Factors

Abstract Plasmonics in two-dimensional materials, an emerging direction of nano-optics, has attracted great attention recently, which exhibits unique properties than that in noble metals. Extending its advanced features by different manipulations is very beneficial for its promotion. In this paper, we study plasmonic excitations in graphene and black phosphorus (BP) nanostructures, where the effects of structural symmetry and material anisotropy are discussed. We show that the two factors are crucial to mode excitations, e.g. the extinction can be dominated by higher order modes rather than dipole resonance. The behavior occurs only in the direction hosting larger resonance frequencies, e.g. armchair (AC) direction of BP and shorter side of graphene rectangles. In BP rectangles along AC direction, the two factors are competing, and thus can be applied cooperatively to tune plasmonic resonance, from dipole to higher order excitations. Besides, the manipulation can also be achieved by designing BP square rings, in which the interaction between outer and inner edges show great impact on mode excitations. Our studies further promote the understanding of plasmonics in two-dimensional materials, and will pave the way for particular plasmonic applications.

A Novel Micromechanical Resonator Using Two-Dimensional Phononic Crystal Slab

2011 ◽  
Vol 254 ◽  
pp. 195-198
Author(s):  
Nan Wang ◽  
Fu Li Hsiao ◽  
Moorthi Palaniapan ◽  
Ming Lin Julius Tsai ◽  
Jeffrey B.W. Soon ◽  
...  
Keyword(s):  
Acoustic Waves ◽  
Phononic Crystal ◽  
Acoustic Resonance ◽  
Two Dimensional ◽  
Free Standing ◽  
Sensing Applications ◽  
Aln Film ◽  
Digital Transducers ◽  
Square Array ◽  
Quality Factor Q

Two-dimensional (2-D) Silicon phononic crystal (PnC) slab of a square array of cylindrical air holes in a 10μm thick free-standing silicon plate with line defects is characterized as a cavity-mode PnC resonator. Piezoelectric aluminum nitride (AlN) film is deployed as the inter-digital transducers (IDT) to transmit and detect acoustic waves, thus making the whole microfabrication process CMOS-compatible. Both the band structure of the PnC and the transmission spectrum of the proposed PnC resonator are analyzed and optimized using finite element method (FEM). The measured quality factor (Q factor) of the microfabricated PnC resonator is over 1,000 at its resonant frequency of 152.46MHz. The proposed PnC resonator shows promising acoustic resonance characteristics for RF communications and sensing applications.

scholarly journals Two-Dimensional Spectral Analysis of Soil Surface Temperature

Hilgardia ◽  
1988 ◽  
Vol 56 (3) ◽  
pp. 1-28 ◽  
Author(s):  
M. Bazza ◽  
R. H. Shumway ◽  
D. R. Nielsen
Keyword(s):  
Spectral Analysis ◽  
Surface Temperature ◽  
Soil Surface ◽  
Two Dimensional ◽  
Soil Surface Temperature

The contrasting hatching patterns and larval growth of two sympatric clingfishes inferred by otolith microstructure analysis

2013 ◽  
Vol 64 (2) ◽  
pp. 157 ◽  
Author(s):  
Jorge E. Contreras ◽  
Mauricio F. Landaeta ◽  
Guido Plaza ◽  
F. Patricio Ojeda ◽  
Claudia A. Bustos
Keyword(s):  
Coastal Waters ◽  
Larval Growth ◽  
Microstructure Analysis ◽  
Larval Abundance ◽  
Otolith Microstructure ◽  
Austral Spring ◽  
Lunar Periodicity ◽  
Central Chile ◽  
Near Shore ◽  
Otolith Microstructure Analysis

Larval abundance, age, growth and hatching patterns of two sympatric clingfishes, Gobiesox marmoratus and Sicyases sanguineus (Pisces, Gobiesocidae), were estimated by using otolith microstructure analysis and compared on the basis of collections performed during the austral spring in 2010 off the coast of central Chile. G. marmoratus larvae were more abundant than S. sanguineus larvae during the study period. For both species, the sagittae deposited micro-increments during embryonic development (before hatching) and a hatch mark was observable in all examined otoliths. The sagittae otoliths of G. marmoratus grew in radius, perimeter and area faster than did the otoliths of S. sanguineus. Both species showed significant (P < 0.05) differences in larval growth and lunar periodicity of the hatching events. G. marmoratus hatched at smaller sizes (2.6 mm) mainly during the first-quarter moon and the larvae grew at rates of 0.24 ± 0.01 mm day–1. S. sanguineus hatched as larger larvae (>3 mm) during the first-quarter and full moons and grew at slower rates (0.14 ± 0.01 mm day–1) during the initial 25 days. The high abundance of larval clingfish in near-shore waters, temporal decoupling among the hatching events, and the different growth rates may be tactics to increase self-recruitment in coastal waters.

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