Waves: Undulatory Motion of a Water Surface
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31 Diffraction and Interference.Pdf
Diffraction and Interference Figu These expar new .5 wave oday Isaac Newton is most famous for his new v accomplishments in mechanics—his laws of Tmotion and universal gravitation. Early in his career, however, he was most famous for his work on light. Newton pictured light as a beam of ultra-tiny material particles. With this model he could explain reflection as a bouncing of the parti- cles from a surface, and he could explain refraction as the result of deflecting forces from the surface Interference colors. acting on the light particles. In the eighteenth and nineteenth cen- turies, this particle model gave way to a wave model of light because waves could explain not only reflection and refraction, but everything else that was known about light at that time. In this chapter we will investigate the wave aspects of light, which are needed to explain two important phenomena—diffraction and interference. As Huygens' Principle origin; 31.1 pie is I constr In the late 1600s a Dutch mathematician-scientist, Christian Huygens, dimen proposed a very interesting idea about waves. Huygens stated that light waves spreading out from a point source may be regarded as die overlapping of tiny secondary wavelets, and that every point on ' any wave front may be regarded as a new point source of secondary waves. We see this in Figure 31.1. In other words, wave fronts are A made up of tinier wave fronts. This idea is called Huygens' principle. Look at the spherical wave front in Figure 31.2. Each point along the wave front AN is the source of a new wavelet that spreads out in a sphere from that point. -
Prelab 5 – Wave Interference
Musical Acoustics Lab, C. Bertulani PreLab 5 – Wave Interference Consider two waves that are in phase, sharing the same frequency and with amplitudes A1 and A2. Their troughs and peaks line up and the resultant wave will have amplitude A = A1 + A2. This is known as constructive interference (figure on the left). If the two waves are π radians, or 180°, out of phase, then one wave's crests will coincide with another waves' troughs and so will tend to cancel itself out. The resultant amplitude is A = |A1 − A2|. If A1 = A2, the resultant amplitude will be zero. This is known as destructive interference (figure on the right). When two sinusoidal waves superimpose, the resulting waveform depends on the frequency (or wavelength) amplitude and relative phase of the two waves. If the two waves have the same amplitude A and wavelength the resultant waveform will have an amplitude between 0 and 2A depending on whether the two waves are in phase or out of phase. The principle of superposition of waves states that the resultant displacement at a point is equal to the vector sum of the displacements of different waves at that point. If a crest of a wave meets a crest of another wave at the same point then the crests interfere constructively and the resultant crest wave amplitude is increased; similarly two troughs make a trough of increased amplitude. If a crest of a wave meets a trough of another wave then they interfere destructively, and the overall amplitude is decreased. This form of interference can occur whenever a wave can propagate from a source to a destination by two or more paths of different lengths. -
Geology of Hawaii Reefs
11 Geology of Hawaii Reefs Charles H. Fletcher, Chris Bochicchio, Chris L. Conger, Mary S. Engels, Eden J. Feirstein, Neil Frazer, Craig R. Glenn, Richard W. Grigg, Eric E. Grossman, Jodi N. Harney, Ebitari Isoun, Colin V. Murray-Wallace, John J. Rooney, Ken H. Rubin, Clark E. Sherman, and Sean Vitousek 11.1 Geologic Framework The eight main islands in the state: Hawaii, Maui, Kahoolawe , Lanai , Molokai , Oahu , Kauai , of the Hawaii Islands and Niihau , make up 99% of the land area of the Hawaii Archipelago. The remainder comprises 11.1.1 Introduction 124 small volcanic and carbonate islets offshore The Hawaii hot spot lies in the mantle under, or of the main islands, and to the northwest. Each just to the south of, the Big Island of Hawaii. Two main island is the top of one or more massive active subaerial volcanoes and one active submarine shield volcanoes (named after their long low pro- volcano reveal its productivity. Centrally located on file like a warriors shield) extending thousands of the Pacific Plate, the hot spot is the source of the meters to the seafloor below. Mauna Kea , on the Hawaii Island Archipelago and its northern arm, the island of Hawaii, stands 4,200 m above sea level Emperor Seamount Chain (Fig. 11.1). and 9,450 m from seafloor to summit, taller than This system of high volcanic islands and asso- any other mountain on Earth from base to peak. ciated reefs, banks, atolls, sandy shoals, and Mauna Loa , the “long” mountain, is the most seamounts spans over 30° of latitude across the massive single topographic feature on the planet. -
Coastal Water Levels
Guidance for Flood Risk Analysis and Mapping Coastal Water Levels May 2016 Requirements for the Federal Emergency Management Agency (FEMA) Risk Mapping, Assessment, and Planning (Risk MAP) Program are specified separately by statute, regulation, or FEMA policy (primarily the Standards for Flood Risk Analysis and Mapping). This document provides guidance to support the requirements and recommends approaches for effective and efficient implementation. Alternate approaches that comply with all requirements are acceptable. For more information, please visit the FEMA Guidelines and Standards for Flood Risk Analysis and Mapping webpage (www.fema.gov/guidelines-and-standards-flood-risk-analysis-and- mapping). Copies of the Standards for Flood Risk Analysis and Mapping policy, related guidance, technical references, and other information about the guidelines and standards development process are all available here. You can also search directly by document title at www.fema.gov/library. Water Levels May 2016 Guidance Document 67 Page i Document History Affected Section or Date Description Subsection Initial version of new transformed guidance. The content was derived from the Guidelines and Specifications for Flood Hazard Mapping Partners, Procedure Memoranda, First Publication May 2016 and/or Operating Guidance documents. It has been reorganized and is being published separately from the standards. Water Levels May 2016 Guidance Document 67 Page ii Table of Contents 1.0 Topic Overview ................................................................................................................. -
NANOOS Asset List 1 National Oceanic and Atmospheric
NANOOS Asset List 2008 NANOOS Asset List 1 National Oceanic and Atmospheric Administration 1.1 The CoastWatch West Coast Regional Node http://coastwatch.pfel.noaa.gov Daily – Monthly composites of satellite observations Sea Surface Temperature (GOES & POES) Ocean Color (MODIS and SeaWiFS) Ocean Winds (QuikSCAT) 1.2 The National Data Buoy Center http://seaboard.ndbc.noaa.gov/maps/Northwest.shtml 6 Minute – Hourly buoy observations Meteorological Observations (Air Temp., Pressure, Wind Speed and Direction) Ocean Observations (Water Temp., Wave Height, Period and Direction) 1.3 The Center for Operational Oceanographic Products and Services http://tidesandcurrents.noaa.gov http://opendap.co-ops.nos.noaa.gov/content 6 Minute near-shore station observations Meteorological Observations (Air Temp., Pressure, Wind Speed and Direction) Ocean Observations (Water Temp., Water Level) 1.4 NOAAWatch http://www.noaawatch.gov Information related to ongoing environmental events NOAAWatch themes include Air Quality, Droughts, Earthquakes, Excessive Heat, Fire, Flooding, Harmful Algal Blooms (HABs), Oil Spills, Rip Currents, Severe Weather, Space Weather, Tsunamis, and Volcanoes 1.5 National Weather Service http://www.weather.gov Environmental observations and forecasts Coastal and Marine Forecasts Weather Warnings 1 NANOOS Asset List 2008 Surface Pressure Maps Coastal and Marine Observations (Wind, Visibility, Sky Conditions, Temperature, Dew Point, Relative Humidity, Atmospheric Pressure, Pressure tendency) GOES Satellite Observations (Visible, -
Tsunami, Seiches, and Tides Key Ideas Seiches
Tsunami, Seiches, And Tides Key Ideas l The wavelengths of tsunami, seiches and tides are so great that they always behave as shallow-water waves. l Because wave speed is proportional to wavelength, these waves move rapidly through the water. l A seiche is a pendulum-like rocking of water in a basin. l Tsunami are caused by displacement of water by forces that cause earthquakes, by landslides, by eruptions or by asteroid impacts. l Tides are caused by the gravitational attraction of the sun and the moon, by inertia, and by basin resonance. 1 Seiches What are the characteristics of a seiche? Water rocking back and forth at a specific resonant frequency in a confined area is a seiche. Seiches are also called standing waves. The node is the position in a standing wave where water moves sideways, but does not rise or fall. 2 1 Seiches A seiche in Lake Geneva. The blue line represents the hypothetical whole wave of which the seiche is a part. 3 Tsunami and Seismic Sea Waves Tsunami are long-wavelength, shallow-water, progressive waves caused by the rapid displacement of ocean water. Tsunami generated by the vertical movement of earth along faults are seismic sea waves. What else can generate tsunami? llandslides licebergs falling from glaciers lvolcanic eruptions lother direct displacements of the water surface 4 2 Tsunami and Seismic Sea Waves A tsunami, which occurred in 1946, was generated by a rupture along a submerged fault. The tsunami traveled at speeds of 212 meters per second. 5 Tsunami Speed How can the speed of a tsunami be calculated? Remember, because tsunami have extremely long wavelengths, they always behave as shallow water waves. -
Part II-1 Water Wave Mechanics
Chapter 1 EM 1110-2-1100 WATER WAVE MECHANICS (Part II) 1 August 2008 (Change 2) Table of Contents Page II-1-1. Introduction ............................................................II-1-1 II-1-2. Regular Waves .........................................................II-1-3 a. Introduction ...........................................................II-1-3 b. Definition of wave parameters .............................................II-1-4 c. Linear wave theory ......................................................II-1-5 (1) Introduction .......................................................II-1-5 (2) Wave celerity, length, and period.......................................II-1-6 (3) The sinusoidal wave profile...........................................II-1-9 (4) Some useful functions ...............................................II-1-9 (5) Local fluid velocities and accelerations .................................II-1-12 (6) Water particle displacements .........................................II-1-13 (7) Subsurface pressure ................................................II-1-21 (8) Group velocity ....................................................II-1-22 (9) Wave energy and power.............................................II-1-26 (10)Summary of linear wave theory.......................................II-1-29 d. Nonlinear wave theories .................................................II-1-30 (1) Introduction ......................................................II-1-30 (2) Stokes finite-amplitude wave theory ...................................II-1-32 -
The Emergence of Magnetic Skyrmions
The emergence of magnetic skyrmions During the past decade, axisymmetric two-dimensional solitons (so-called magnetic skyrmions) have been discovered in several materials. These nanometer-scale chiral objects are being proposed as candidates for novel technological applications, including high-density memory, logic circuits and neuro-inspired computing. Alexei N. Bogdanov and Christos Panagopoulos Research on magnetic skyrmions benefited from a cascade of breakthroughs in magnetism and nonlinear physics. These magnetic objects are believed to be nanometers-size whirling cylinders, embedded into a magnetically saturated state and magnetized antiparallel along their axis (Fig. 1). They are topologically stable, in the sense that they can’t be continuously transformed into homogeneous state. Being highly mobile and the smallest magnetic configurations, skyrmions are promising for applications in the emerging field of spintronics, wherein information is carried by the electron spin further to, or instead of the electron charge. Expectedly, their scientific and technological relevance is fueling inventive research in novel classes of bulk magnetic materials and synthetic architectures [1, 2]. The unconventional and useful features of magnetic skyrmions have become focus of attention in the science and technology Figure 1. Magnetic skyrmions are nanoscale spinning magnetic circles, sometimes teasingly called “magic knots” or “mysterious cylinders (a), embedded into the saturated state of ferromagnets (b). particles”. Interestingly, for a long time it remained widely In the skyrmion core, magnetization gradually rotates along radial unknown that the key “mystery” surrounding skyrmions is in the directions with a fixed rotation sense namely, from antiparallel very fact of their existence. Indeed, mathematically the majority of direction at the axis to a parallel direction at large distances from the physical systems with localized structures similar to skyrmions are center. -
Lecture 9, P 1 Lecture 9: Introduction to QM: Review and Examples
Lecture 9, p 1 Lecture 9: Introduction to QM: Review and Examples S1 S2 Lecture 9, p 2 Photoelectric Effect Binding KE=⋅ eV = hf −Φ energy max stop Φ The work function: 3.5 Φ is the minimum energy needed to strip 3 an electron from the metal. 2.5 2 (v) Φ is defined as positive . 1.5 stop 1 Not all electrons will leave with the maximum V f0 kinetic energy (due to losses). 0.5 0 0 5 10 15 Conclusions: f (x10 14 Hz) • Light arrives in “packets” of energy (photons ). • Ephoton = hf • Increasing the intensity increases # photons, not the photon energy. Each photon ejects (at most) one electron from the metal. Recall: For EM waves, frequency and wavelength are related by f = c/ λ. Therefore: Ephoton = hc/ λ = 1240 eV-nm/ λ Lecture 9, p 3 Photoelectric Effect Example 1. When light of wavelength λ = 400 nm shines on lithium, the stopping voltage of the electrons is Vstop = 0.21 V . What is the work function of lithium? Lecture 9, p 4 Photoelectric Effect: Solution 1. When light of wavelength λ = 400 nm shines on lithium, the stopping voltage of the electrons is Vstop = 0.21 V . What is the work function of lithium? Φ = hf - eV stop Instead of hf, use hc/ λ: 1240/400 = 3.1 eV = 3.1eV - 0.21eV For Vstop = 0.21 V, eV stop = 0.21 eV = 2.89 eV Lecture 9, p 5 Act 1 3 1. If the workfunction of the material increased, (v) 2 how would the graph change? stop a. -
Sea State in Marine Safety Information Present State, Future Prospects
Sea State in Marine Safety Information Present State, future prospects Henri SAVINA – Jean-Michel LEFEVRE Météo-France Rogue Waves 2004, Brest 20-22 October 2004 JCOMM Joint WMO/IOC Commission for Oceanography and Marine Meteorology The future of Operational Oceanography Intergovernmental body of technical experts in the field of oceanography and marine meteorology, with a mandate to prepare both regulatory (what Member States shall do) and guidance (what Member States should do) material. TheThe visionvision ofof JCOMMJCOMM Integrated ocean observing system Integrated data management State-of-the-art technologies and capabilities New products and services User responsiveness and interaction Involvement of all maritime countries JCOMM structure Terms of Reference Expert Team on Maritime Safety Services • Monitor / review operations of marine broadcast systems, including GMDSS and others for vessels not covered by the SOLAS convention •Monitor / review technical and service quality standards for meteo and oceano MSI, particularly for the GMDSS, and provide assistance and support to Member States • Ensure feedback from users is obtained through appropriate channels and applied to improve the relevance, effectiveness and quality of services • Ensure effective coordination and cooperation with organizations, bodies and Member States on maritime safety issues • Propose actions as appropriate to meet requirements for international coordination of meteorological and related communication services • Provide advice to the SCG and other Groups of JCOMM on issues related to MSS Chair selected by Commission. OPEN membership, including representatives of the Issuing Services for GMDSS, of IMO, IHO, ICS, IMSO, and other user groups GMDSS Global Maritime Distress & Safety System Defined by IMO for the provision of MSI and the coordination of SAR alerts on a global basis. -
This Content Is Prepared from Various Sources and Has Used the Study Material from Various Books, Internet Articles Etc
This content is prepared from various sources and has used the study material from various books, internet articles etc. The teacher doesn’t claim any right over the content, it’s originality and any copyright. It is given only to the students of PG course in Geology to study as a part of their curriculum. WAVES Waves and their properties. (a) Regular, symmetrical waves can be described by their height, wavelength, and period (the time one wavelength takes to pass a fixed point). (b) Waves can be classified according to their wave period. The scales of wave height and wave period are not linear, but logarithmic, being based on powers of 10. The variety and size of wind-generated waves are controlled by four principal factors: (1) wind velocity, (2) wind duration, (3) fetch, (4) original sea state. Significant Wave Height? What is the average height and what is the significant height? Wind-generated waves are progressive waves, because they travel (progress) across the sea surface. If you focus on the crest of a progressive wave, you can follow its path over time. But what actually is moving? The wave form obviously is moving, but what about the water just below the sea surface? Actually, two basic kinds of motions are associated with ocean waves: the forward movement of the wave form itself and the orbital motion of water particles beneath the wave. The motion of water particles beneath waves. (a) The arrows at the sea surface denote the motion of water particles beneath waves. With the passage of one wavelength, a water particle at the sea surface describes a circular orbit with a diameter equal to the wave’s height. -
Sea State Effect on the Sea Surface Emissivity at L-Band
View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by UPCommons. Portal del coneixement obert de la UPC IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING, VOL. 41, NO. 10, OCTOBER 2003 2307 Sea State Effect on the Sea Surface Emissivity at L-Band Jorge José Miranda, Mercè Vall-llossera, Member, IEEE, Adriano Camps, Senior Member, IEEE, Núria Duffo, Member, IEEE, Ignasi Corbella, Member, IEEE, and Jacqueline Etcheto Abstract—In May 1999, the European Space Agency (ESA) temperature images will provide looks of the same pixel under selected the Earth Explorer Opportunity Soil Moisture and incidence angles from 0 to almost 65 , which requires the Ocean Salinity (SMOS) mission to obtain global and frequent soil development of soil and sea emission models in the whole moisture and ocean salinity maps. SMOS single payload is the Microwave Imaging Radiometer by Aperture Synthesis (MIRAS), range of incidence angles, and suitable geophysical parameters an L-band two-dimensional aperture synthesis radiometer with retrieval algorithms. multiangular observation capabilities. At L-band, the brightness The dielectric permittivity for seawater is determined, among temperature sensitivity to the sea surface salinity (SSS) is low, other variables, by salinity. Therefore, in principle, it is possible approximately 0.5 K/psu at 20 C, decreasing to 0.25 K/psu at to retrieve SSS from passive microwave measurements as long 0 C, comparable to that to the wind speed 0.2 K/(m/s) at nadir. However, at a given time, the sea state does not depend only as the variables influencing the brightness temperature (TB) on local winds, but on the local wind history and the presence signal (sea surface temperature, roughness, and foam) can be of waves traveling from far distances.