The document summarizes principles for capturing energy from ocean waves through oscillating water column devices or floating bodies. It discusses that:
1) To absorb wave energy, a device must displace water in an oscillating manner that is in the correct phase with the incoming waves to destructively interfere and cancel them out.
2) For maximum energy capture, a device needs to oscillate at the optimum amplitude and phase for the incoming wave conditions. The phase should match the natural frequency of the device or be controlled to do so.
3) Phase control can be achieved through "latching" where a small amount of energy is returned to the sea during each cycle to better match the phase of the incoming waves
- The document discusses transverse and longitudinal waves. Transverse waves have a disturbance perpendicular to the direction of propagation, while longitudinal waves have a disturbance parallel to the direction of propagation.
- It provides examples of different types of waves - ocean water waves are a combination of transverse and longitudinal waves, while waves on guitar strings are transverse. Sound waves in air and water are longitudinal.
- Differentiating between longitudinal and transverse waves is important because the energy and motion propagate in different directions for each type of wave. This affects how the waves behave and transfer energy.
1. The document discusses various topics related to waves, optics, oscillation, and gravitation. It defines key terms like traveling waves, standing waves, and wave propagation.
2. Important concepts are covered, including the principle of superposition, simple harmonic motion, Newton's laws of gravitation, and Kepler's laws of planetary motion.
3. Examples are provided to demonstrate applications of these concepts, such as calculating spring oscillation properties and determining values related to a vibrating string and pendulum motion.
The document discusses several optical phenomena including:
1) The law of reflection states that the angle of incidence of a light ray equals the angle of reflection.
2) Transmission of light refers to the percentage of incident light that passes through a medium.
3) Refraction causes light to bend when passing from one medium to another with a different speed, as described by Snell's law.
This document discusses different types of waves including transverse and longitudinal waves. It defines key wave properties such as amplitude, wavelength, frequency, period, and speed. It also covers the electromagnetic spectrum and provides examples of sources that produce different types of electromagnetic waves like gamma rays, x-rays, ultraviolet light, visible light, infrared, microwaves, and radio waves.
This document discusses different types of waves including transverse waves, longitudinal waves, and electromagnetic waves. It defines key wave properties such as amplitude, wavelength, frequency, speed, and period. It provides examples of calculating wavelength, frequency, and speed using the wave equations. The document also covers the electromagnetic spectrum and properties of different regions including gamma rays, x-rays, ultraviolet, visible light, infrared, microwaves, and radio waves.
The document discusses reflection and transmission of mechanical waves at discontinuities in materials. It explains that waves can be reflected, transmitted, or absorbed depending on whether the wave's frequency matches the object's natural vibration frequencies. Reflection occurs if vibrations are not passed through the material, while transmission occurs if vibrations pass through. The document then applies these concepts to analyze reflection and transmission of pressure waves in arteries at locations where properties change, like narrowing, widening, or bifurcations into branches. Mathematical formulas are presented to calculate reflection and transmission coefficients at such discontinuities.
This document discusses driven harmonic oscillators. It explains that a damped oscillator will slow down over time due to friction, but an external driving force can counteract this and sustain the oscillations. Resonance occurs when the driving frequency matches the natural frequency of the system. Under resonance conditions, the amplitude of the oscillation will not decrease as the system is absorbing energy at the same rate it is losing it. The driving force can be represented by a harmonic function.
This document summarizes key concepts from Chapter 10 of a Giambattista physics textbook. It covers elasticity and oscillations, including elastic deformations of solids, Hooke's law, shear and volume deformations, simple harmonic motion, the pendulum, and damped and forced oscillations. Example problems demonstrate applying concepts like Hooke's law to calculate deformations of materials under stress. Diagrams illustrate oscillatory motion, restoring forces, and the conservation of energy in simple harmonic systems.
- The document discusses transverse and longitudinal waves. Transverse waves have a disturbance perpendicular to the direction of propagation, while longitudinal waves have a disturbance parallel to the direction of propagation.
- It provides examples of different types of waves - ocean water waves are a combination of transverse and longitudinal waves, while waves on guitar strings are transverse. Sound waves in air and water are longitudinal.
- Differentiating between longitudinal and transverse waves is important because the energy and motion propagate in different directions for each type of wave. This affects how the waves behave and transfer energy.
1. The document discusses various topics related to waves, optics, oscillation, and gravitation. It defines key terms like traveling waves, standing waves, and wave propagation.
2. Important concepts are covered, including the principle of superposition, simple harmonic motion, Newton's laws of gravitation, and Kepler's laws of planetary motion.
3. Examples are provided to demonstrate applications of these concepts, such as calculating spring oscillation properties and determining values related to a vibrating string and pendulum motion.
The document discusses several optical phenomena including:
1) The law of reflection states that the angle of incidence of a light ray equals the angle of reflection.
2) Transmission of light refers to the percentage of incident light that passes through a medium.
3) Refraction causes light to bend when passing from one medium to another with a different speed, as described by Snell's law.
This document discusses different types of waves including transverse and longitudinal waves. It defines key wave properties such as amplitude, wavelength, frequency, period, and speed. It also covers the electromagnetic spectrum and provides examples of sources that produce different types of electromagnetic waves like gamma rays, x-rays, ultraviolet light, visible light, infrared, microwaves, and radio waves.
This document discusses different types of waves including transverse waves, longitudinal waves, and electromagnetic waves. It defines key wave properties such as amplitude, wavelength, frequency, speed, and period. It provides examples of calculating wavelength, frequency, and speed using the wave equations. The document also covers the electromagnetic spectrum and properties of different regions including gamma rays, x-rays, ultraviolet, visible light, infrared, microwaves, and radio waves.
The document discusses reflection and transmission of mechanical waves at discontinuities in materials. It explains that waves can be reflected, transmitted, or absorbed depending on whether the wave's frequency matches the object's natural vibration frequencies. Reflection occurs if vibrations are not passed through the material, while transmission occurs if vibrations pass through. The document then applies these concepts to analyze reflection and transmission of pressure waves in arteries at locations where properties change, like narrowing, widening, or bifurcations into branches. Mathematical formulas are presented to calculate reflection and transmission coefficients at such discontinuities.
This document discusses driven harmonic oscillators. It explains that a damped oscillator will slow down over time due to friction, but an external driving force can counteract this and sustain the oscillations. Resonance occurs when the driving frequency matches the natural frequency of the system. Under resonance conditions, the amplitude of the oscillation will not decrease as the system is absorbing energy at the same rate it is losing it. The driving force can be represented by a harmonic function.
This document summarizes key concepts from Chapter 10 of a Giambattista physics textbook. It covers elasticity and oscillations, including elastic deformations of solids, Hooke's law, shear and volume deformations, simple harmonic motion, the pendulum, and damped and forced oscillations. Example problems demonstrate applying concepts like Hooke's law to calculate deformations of materials under stress. Diagrams illustrate oscillatory motion, restoring forces, and the conservation of energy in simple harmonic systems.
1. Maxwell's equations predict that electromagnetic energy propagates away from time-varying sources in the form of waves.
2. The document derives the electromagnetic wave equation and describes its solution for uniform plane waves in various media.
3. Key wave properties like velocity, wavelength, frequency and attenuation are determined by examining solutions to the wave equations for the electric and magnetic fields.
This document provides instructions for navigating a presentation on vibrations and waves. It begins with directions for viewing the presentation as a slideshow and advancing through it. It then lists the chapter contents which cover topics like simple harmonic motion, wave properties, and wave interactions. Sample problems and objectives are provided for each section. The document concludes with multiple choice questions related to simple harmonic motion.
This document provides a summary of Chapter 11 from a physics textbook on waves. It covers key topics about waves including: types of waves (transverse, longitudinal), speed and wavelength of waves, periodic and harmonic waves, the principle of superposition, reflection and refraction, interference, diffraction, and standing waves. Examples are provided to illustrate concepts such as calculating wave speed and wavelength. The chapter concludes with a discussion of standing waves on a string, including the conditions required to form standing waves and their characteristic node and antinode patterns.
This document provides instructions for navigating a presentation on vibrations and waves. It can be viewed as a slideshow and contains sections on simple harmonic motion, measuring simple harmonic motion, properties of waves, and wave interactions. Each section contains objectives, explanations of concepts, sample problems, and visualizations. Users can access specific lessons or resources from the chapter menu. The presentation is intended to help students understand key topics relating to vibrations and waves.
Oscillations and waves can be described by key parameters including amplitude, period, and frequency. Amplitude refers to the maximum displacement from equilibrium, period is the time for one full oscillation, and frequency is the number of oscillations per second. Common examples of oscillations include a pendulum, mass on a spring, and ocean tides. For an object to undergo simple harmonic motion, it must experience a restoring force proportional to and directed towards its displacement from equilibrium.
The document discusses wave behavior and reflection and refraction of waves. It provides examples of reflection at fixed and free boundaries and how this causes inversion or no inversion of pulses. It introduces the law of reflection where the angle of incidence equals the angle of reflection. Refraction is discussed where the speed and wavelength change upon entering a new medium. Snell's law is derived relating the sines of the angles of incidence and refraction to the refractive indices of the media. Total internal reflection at the critical angle is also mentioned.
This presentation discusses various topics related to wave motion, including:
1. The wave equation, which is an important differential equation used to describe waves in various fields like acoustics and fluid dynamics.
2. Plane progressive waves in fluid media, which travel continuously in the same direction without changing amplitude.
3. The principle of superposition, which states that when two or more waves pass through the same medium at the same time, the net displacement at any point is the sum of the individual wave displacements.
Here are the answers to the lab preparation problems:
1. A wave on the water surface is a transverse wave. The oscillation of the water surface is perpendicular to the direction of wave propagation.
2. The wavelength of visible light ranges from 400-800nm. Using the formula c=fλ, where c is the speed of light (3x108 m/s), we can calculate:
f = c/λ
f = (3x108 m/s) / (400x10-9 - 800x10-9) m
f = 7.5x1014 - 3.75x1014 Hz
3. A standing wave is produced with a frequency of 60 Hz. The
This document provides an overview of key concepts in sound and wave physics from Chapter 12 of Giambattista Physics. It covers sound waves, the speed of sound in different materials, amplitude and intensity, standing waves, timbre, and the human ear. Key points include: sound waves involve variations in pressure and displacement of air molecules; the speed of sound depends on factors like temperature, density, and elastic properties of the medium; amplitude relates to loudness while intensity relates to energy carried; and timbre is determined by the relative amplitudes of the fundamental frequency and overtones.
This document provides an overview of chapter 8 from a physics textbook on torque and angular momentum. The chapter covers rotational kinetic energy, torque, calculating work from torque, rotational equilibrium, rotational forms of Newton's laws, motion of rolling objects, and angular momentum. It includes definitions, concepts, examples, and equations related to these topics. Sample problems are worked through on rotational inertia, torque, work from torque, and bringing a potter's wheel up to speed. Diagrams are provided to illustrate concepts like torque as a function of force and distance from the axis of rotation.
This document discusses plans for gravitational wave observatories that could detect gravitational waves predicted by Einstein's theory of general relativity. The observatories would use laser interferometers housed in evacuated pipes stretching hundreds of meters to detect tiny distortions in space caused by passing gravitational waves. Two major observatories, LIGO, are being built in the U.S. to be sensitive enough to detect signals from binary star systems, supernovae, and colliding black holes in nearby galaxies. The first detection of gravitational waves would verify crucial predictions of general relativity and reveal new information about astrophysical events.
This document discusses electromagnetic waves and Maxwell's equations. It provides an overview of key topics:
- Maxwell derived equations showing electric and magnetic fields form propagating waves at the speed of light.
- The electromagnetic spectrum ranges from radio to gamma rays. Waves are generated by oscillating electric fields creating magnetic fields and vice versa.
- Maxwell's equations precisely relate the electric and magnetic fields and how they vary over time. This allowed calculation of the waves' speed as the measured speed of light.
This document discusses longitudinal waves, in which particle motion is parallel to the direction of wave propagation. Longitudinal waves include sound waves, which can propagate through gases, liquids, and solids. The document describes how a periodic longitudinal wave can be produced by a piston moving with simple harmonic motion, causing variations in pressure and density. It defines key characteristics of longitudinal waves like displacement, pressure variation, wavelength, frequency, speed and relates these to properties of the medium like bulk modulus and density. The speed of sound, power, intensity, and the inverse square law for intensity from a point source are also covered.
This experiment studied standing waves by measuring the length of an air column needed to produce resonance at different tuning fork frequencies. The length increased as the period of the tuning fork increased. Graphs of frequency vs. length and period vs. length showed a linear relationship. Only 3 data points were within the trend, limiting accuracy. Using more tuning forks and tubes of varying diameters could improve the experiment.
The document discusses the nature of photons and electromagnetic waves. It describes a photon as a self-sustaining, traveling electromagnetic wavepacket that propagates at the speed of light. A photon is also characterized as a spin wave with quantized spin angular momentum. Photons are interpreted as disturbances in a quantum vacuum composed of Planck mass dipoles, with the electric field representing an alignment of these dipoles and the magnetic field representing their vortical motion. Electromagnetic wave propagation, reflection, refraction, and diffraction are also examined in the context of the quantum vacuum.
This document is a lecture presentation on electromagnetic wave propagation by Mr. Himanshu Diwakar. It includes:
- An outline discussing Maxwell's equations, the Helmholtz equation, propagation constant, properties of electromagnetic waves, and wave propagation in free space.
- A note emphasizing the need to review electrostatics, magnetostatics, and vector identities to fully understand electromagnetic waves.
- Explanations of the Pointing theorem, which states that the time rate of change of electromagnetic energy within a volume plus the net energy flowing out equals the work done on charges within the volume.
- Definitions of the Poynting vector and its relationship to the electric and magnetic
This document provides an overview of key concepts in engineering physics related to oscillations and waves. It defines terms like displacement, amplitude, frequency, period, equilibrium position, and angular frequency. It describes simple harmonic motion and derives the differential equation of motion. It also covers topics like restoring force, force constant, free and forced vibrations, damping, and quality factor. The document is intended as course material for an engineering physics module taught by Dr. Dileep C.S. in the department of physics.
The document discusses research conducted on eating disorders in athletes. A survey assessed factors contributing to eating disorders and sports most focused on body weight. Focus groups asked about diagnostic criteria and prevention. Interviews revealed coaches and athletes should be educated young to prevent disorders. The data helped narrow the topic to how society influences disorders in athletes and that coaches and athletes are the key targets for education to decrease prevalence.
[TCC] Apresentacao - Agrupamento de InstânciasAugusto Giles
Este documento descreve um algoritmo guloso para agrupamento de dados duplicados. O algoritmo gera tokens para representar os dados, constrói um grafo de similaridade e então agrupa os dados iterativamente usando operações de fusão, divisão e movimentação de clusters para maximizar a similaridade média dentro dos clusters. O algoritmo é implementado para identificar dados duplicados em grandes volumes de dados de forma incremental e recuperável.
Este documento discute NoSQL e bancos de dados orientados a colunas. Apresenta o conceito de NoSQL, suas propriedades e o Teorema CAP. Descreve o modelo de dados orientado a colunas e ferramentas como BigTable, Cassandra e HBase. Por fim, discute perspectivas futuras para NoSQL e fornece referências.
Geneo Software Overview Mar 2012 Suggested Slides Copybobnewton1
Software to support and sustain the implementation of lean enterprise. Rapid standard work document build, control and version, with competency management.
1. Maxwell's equations predict that electromagnetic energy propagates away from time-varying sources in the form of waves.
2. The document derives the electromagnetic wave equation and describes its solution for uniform plane waves in various media.
3. Key wave properties like velocity, wavelength, frequency and attenuation are determined by examining solutions to the wave equations for the electric and magnetic fields.
This document provides instructions for navigating a presentation on vibrations and waves. It begins with directions for viewing the presentation as a slideshow and advancing through it. It then lists the chapter contents which cover topics like simple harmonic motion, wave properties, and wave interactions. Sample problems and objectives are provided for each section. The document concludes with multiple choice questions related to simple harmonic motion.
This document provides a summary of Chapter 11 from a physics textbook on waves. It covers key topics about waves including: types of waves (transverse, longitudinal), speed and wavelength of waves, periodic and harmonic waves, the principle of superposition, reflection and refraction, interference, diffraction, and standing waves. Examples are provided to illustrate concepts such as calculating wave speed and wavelength. The chapter concludes with a discussion of standing waves on a string, including the conditions required to form standing waves and their characteristic node and antinode patterns.
This document provides instructions for navigating a presentation on vibrations and waves. It can be viewed as a slideshow and contains sections on simple harmonic motion, measuring simple harmonic motion, properties of waves, and wave interactions. Each section contains objectives, explanations of concepts, sample problems, and visualizations. Users can access specific lessons or resources from the chapter menu. The presentation is intended to help students understand key topics relating to vibrations and waves.
Oscillations and waves can be described by key parameters including amplitude, period, and frequency. Amplitude refers to the maximum displacement from equilibrium, period is the time for one full oscillation, and frequency is the number of oscillations per second. Common examples of oscillations include a pendulum, mass on a spring, and ocean tides. For an object to undergo simple harmonic motion, it must experience a restoring force proportional to and directed towards its displacement from equilibrium.
The document discusses wave behavior and reflection and refraction of waves. It provides examples of reflection at fixed and free boundaries and how this causes inversion or no inversion of pulses. It introduces the law of reflection where the angle of incidence equals the angle of reflection. Refraction is discussed where the speed and wavelength change upon entering a new medium. Snell's law is derived relating the sines of the angles of incidence and refraction to the refractive indices of the media. Total internal reflection at the critical angle is also mentioned.
This presentation discusses various topics related to wave motion, including:
1. The wave equation, which is an important differential equation used to describe waves in various fields like acoustics and fluid dynamics.
2. Plane progressive waves in fluid media, which travel continuously in the same direction without changing amplitude.
3. The principle of superposition, which states that when two or more waves pass through the same medium at the same time, the net displacement at any point is the sum of the individual wave displacements.
Here are the answers to the lab preparation problems:
1. A wave on the water surface is a transverse wave. The oscillation of the water surface is perpendicular to the direction of wave propagation.
2. The wavelength of visible light ranges from 400-800nm. Using the formula c=fλ, where c is the speed of light (3x108 m/s), we can calculate:
f = c/λ
f = (3x108 m/s) / (400x10-9 - 800x10-9) m
f = 7.5x1014 - 3.75x1014 Hz
3. A standing wave is produced with a frequency of 60 Hz. The
This document provides an overview of key concepts in sound and wave physics from Chapter 12 of Giambattista Physics. It covers sound waves, the speed of sound in different materials, amplitude and intensity, standing waves, timbre, and the human ear. Key points include: sound waves involve variations in pressure and displacement of air molecules; the speed of sound depends on factors like temperature, density, and elastic properties of the medium; amplitude relates to loudness while intensity relates to energy carried; and timbre is determined by the relative amplitudes of the fundamental frequency and overtones.
This document provides an overview of chapter 8 from a physics textbook on torque and angular momentum. The chapter covers rotational kinetic energy, torque, calculating work from torque, rotational equilibrium, rotational forms of Newton's laws, motion of rolling objects, and angular momentum. It includes definitions, concepts, examples, and equations related to these topics. Sample problems are worked through on rotational inertia, torque, work from torque, and bringing a potter's wheel up to speed. Diagrams are provided to illustrate concepts like torque as a function of force and distance from the axis of rotation.
This document discusses plans for gravitational wave observatories that could detect gravitational waves predicted by Einstein's theory of general relativity. The observatories would use laser interferometers housed in evacuated pipes stretching hundreds of meters to detect tiny distortions in space caused by passing gravitational waves. Two major observatories, LIGO, are being built in the U.S. to be sensitive enough to detect signals from binary star systems, supernovae, and colliding black holes in nearby galaxies. The first detection of gravitational waves would verify crucial predictions of general relativity and reveal new information about astrophysical events.
This document discusses electromagnetic waves and Maxwell's equations. It provides an overview of key topics:
- Maxwell derived equations showing electric and magnetic fields form propagating waves at the speed of light.
- The electromagnetic spectrum ranges from radio to gamma rays. Waves are generated by oscillating electric fields creating magnetic fields and vice versa.
- Maxwell's equations precisely relate the electric and magnetic fields and how they vary over time. This allowed calculation of the waves' speed as the measured speed of light.
This document discusses longitudinal waves, in which particle motion is parallel to the direction of wave propagation. Longitudinal waves include sound waves, which can propagate through gases, liquids, and solids. The document describes how a periodic longitudinal wave can be produced by a piston moving with simple harmonic motion, causing variations in pressure and density. It defines key characteristics of longitudinal waves like displacement, pressure variation, wavelength, frequency, speed and relates these to properties of the medium like bulk modulus and density. The speed of sound, power, intensity, and the inverse square law for intensity from a point source are also covered.
This experiment studied standing waves by measuring the length of an air column needed to produce resonance at different tuning fork frequencies. The length increased as the period of the tuning fork increased. Graphs of frequency vs. length and period vs. length showed a linear relationship. Only 3 data points were within the trend, limiting accuracy. Using more tuning forks and tubes of varying diameters could improve the experiment.
The document discusses the nature of photons and electromagnetic waves. It describes a photon as a self-sustaining, traveling electromagnetic wavepacket that propagates at the speed of light. A photon is also characterized as a spin wave with quantized spin angular momentum. Photons are interpreted as disturbances in a quantum vacuum composed of Planck mass dipoles, with the electric field representing an alignment of these dipoles and the magnetic field representing their vortical motion. Electromagnetic wave propagation, reflection, refraction, and diffraction are also examined in the context of the quantum vacuum.
This document is a lecture presentation on electromagnetic wave propagation by Mr. Himanshu Diwakar. It includes:
- An outline discussing Maxwell's equations, the Helmholtz equation, propagation constant, properties of electromagnetic waves, and wave propagation in free space.
- A note emphasizing the need to review electrostatics, magnetostatics, and vector identities to fully understand electromagnetic waves.
- Explanations of the Pointing theorem, which states that the time rate of change of electromagnetic energy within a volume plus the net energy flowing out equals the work done on charges within the volume.
- Definitions of the Poynting vector and its relationship to the electric and magnetic
This document provides an overview of key concepts in engineering physics related to oscillations and waves. It defines terms like displacement, amplitude, frequency, period, equilibrium position, and angular frequency. It describes simple harmonic motion and derives the differential equation of motion. It also covers topics like restoring force, force constant, free and forced vibrations, damping, and quality factor. The document is intended as course material for an engineering physics module taught by Dr. Dileep C.S. in the department of physics.
The document discusses research conducted on eating disorders in athletes. A survey assessed factors contributing to eating disorders and sports most focused on body weight. Focus groups asked about diagnostic criteria and prevention. Interviews revealed coaches and athletes should be educated young to prevent disorders. The data helped narrow the topic to how society influences disorders in athletes and that coaches and athletes are the key targets for education to decrease prevalence.
[TCC] Apresentacao - Agrupamento de InstânciasAugusto Giles
Este documento descreve um algoritmo guloso para agrupamento de dados duplicados. O algoritmo gera tokens para representar os dados, constrói um grafo de similaridade e então agrupa os dados iterativamente usando operações de fusão, divisão e movimentação de clusters para maximizar a similaridade média dentro dos clusters. O algoritmo é implementado para identificar dados duplicados em grandes volumes de dados de forma incremental e recuperável.
Este documento discute NoSQL e bancos de dados orientados a colunas. Apresenta o conceito de NoSQL, suas propriedades e o Teorema CAP. Descreve o modelo de dados orientado a colunas e ferramentas como BigTable, Cassandra e HBase. Por fim, discute perspectivas futuras para NoSQL e fornece referências.
Geneo Software Overview Mar 2012 Suggested Slides Copybobnewton1
Software to support and sustain the implementation of lean enterprise. Rapid standard work document build, control and version, with competency management.
This document discusses the importance of safeguarding patient privacy and complying with privacy laws like HIPAA. It notes that all staff must complete annual HIPAA training through a computer-based course with an 80% passing score on the test. Any violations will be investigated and reported to authorities, as required by laws with criminal penalties for non-compliance.
Toluna is a global online research and insights company that provides sample, technology, and services to enable companies to conduct surveys and research. It has over 4 million panelists in 34 countries and uses a community-based approach to engage panelists. Toluna offers a variety of products and services including proprietary panels, surveys, online ad measurement, and consultancy services. It aims to provide opinions from targeted audiences to help companies gain insights.
Este documento descreve um trabalho de graduação sobre agrupamento de instâncias duplicadas no processo de identificação de dados duplicados. O trabalho apresenta uma introdução ao problema, revisa técnicas de agrupamento de dados existentes e descreve em detalhes o algoritmo incremental selecionado para implementação, que é proposto por Gruenheid, Dong e Srivastava. O documento também detalha a implementação realizada e apresenta os resultados de experimentos.
El documento presenta un mensaje corto con varias palabras en mayúsculas que parecen nombrar a integrantes de un equipo y reglas sencillas pero difíciles de comprender, seguido de frases exclamativas sobre no haber sabido antes y una queja sobre la juventud que no avisa. Finalmente, nombra factores como la ignorancia, la rapidez, la comodidad y el uso excesivo de redes sociales y celulares que pueden llevar al olvido de las reglas gramaticales.
The document discusses the benefits of exercise for mental health. Regular physical activity can help reduce anxiety and depression and improve mood and cognitive function. Exercise causes chemical changes in the brain that may help protect against mental illness and improve symptoms.
This document provides panel size and internet penetration statistics for 16 countries in the Asia Pacific region. It lists the number of panelists in Australia (111,510), China (515,749), Hong Kong (45,327), India (95,727), Indonesia (18,144), Japan (225,005), Malaysia (41,353), New Zealand (21,573), Philippines (25,321), Singapore (52,930), South Korea (290,800), Taiwan (77,990), Thailand (19,638), and Vietnam (21,465). For each country it also gives the percentage of internet penetration, which ranges from 8% in India to 84% in New Zealand. Contact information is provided for
The document provides an overview of the Company of Young Canadians (CYC), a federal Crown corporation established in 1966 to support volunteer programs for social and community development in Canada. It details the organization's structure and leadership, projects across various regions, and mounting problems that led to its decline and eventual end. Key events included accusations of criminal activity that sparked a parliamentary investigation in 1969, loss of autonomy under tighter government control, and funding cuts that made continuation difficult. While well-intentioned initially, the CYC struggled with bureaucratic challenges and an inability to truly represent youth interests independent of government influence.
Transparency issues continue to plague Ukraine's growing banking sector. While foreign banks have acquired nearly a quarter of Ukraine's banks, a lack of transparency and proper due diligence makes investment difficult. Experts warn that more transparency is needed for the sector to develop along Western standards, including transparent interest rates and risk management practices. Despite issues, the banking sector is expected to continue growing through additional foreign acquisitions and expansion in sectors like mortgages.
Virtualização a Nível de Sistema Operacional e sua Proposta de SegurançaAugusto Giles
Este documento discute a segurança na virtualização de sistemas operacionais. A virtualização permite isolar aplicações e containers, aumentando a proteção contra softwares maliciosos. A virtualização também facilita a recuperação em caso de falhas, permitindo reiniciar containers de forma segura. Embora a virtualização traga benefícios de segurança, ainda há desafios a serem superados para um maior isolamento e tolerância a falhas.
The document discusses decision support systems (DSS), which are computer-based systems that help organizational decision-making. It describes the components, tools, and models used in DSS, including databases, model bases, dialog generation systems, and mathematical models like linear programming. Linear programming is used to optimize outcomes under constraints by finding the best values for decision variables. DSS can help decision-making but also have disadvantages like overemphasizing decisions or obscuring responsibility.
The document discusses influences on adult education theory and practice in Canada during the 1960s and 1970s. Major influences included economic recessions, political shifts to the left, social protests related to class, gender, and youth culture, as well as technological advances like television and automobiles. Researchers began developing theories around adult learning and identifying characteristics of individuals who do and do not participate in adult education programs. This laid the foundation for the discipline of adult education in Canada.
1. O documento discute tecnologias NoSQL orientadas a colunas, comparando o modelo de armazenamento de dados relacional e não relacional.
2. Apresenta três ferramentas de armazenamento de dados orientadas a colunas - BigTable, Apache Cassandra e HBase - descrevendo suas arquiteturas e funcionalidades.
3. Discutem conceitos importantes como o Teorema CAP e os diferentes modelos de armazenamento de dados NoSQL.
The document provides information from a community needs assessment conducted to inform a presentation for a high school health class. An observation of the class found it to be quiet and unparticipatory. A survey of students found most had heard of celiac disease and a gluten-free diet but lacked detailed knowledge. It was determined a presentation on celiac disease, gluten intolerance, and gluten-free diets would be most appropriate, incorporating activities to engage the class.
Linear wave theory assumes wave amplitudes are small, allowing second-order effects to be ignored. It accurately describes real wave behavior including refraction, diffraction, shoaling and breaking. Waves are described by their amplitude, wavelength, frequency, period, wavenumber and phase/group velocities. Phase velocity is the speed at which the wave profile propagates, while group velocity (always lower) is the speed at which wave energy is transmitted. Wave energy is proportional to the square of the amplitude and is divided equally between kinetic and potential components on average.
1. The document discusses various topics in waves, optics, oscillation, and gravitation including traveling waves, standing waves, wave propagation, simple harmonic motion, Newton's laws of gravity, and key terms.
2. Examples are provided to demonstrate calculations for spring oscillation, wave speed in a string, pendulum motion, and gravitational acceleration based on pendulum period.
3. Formulas are listed for spring constant, frequency, wave velocity, and other important relationships.
Wave breaking is a complex phenomenon characterized by energy dissipation and turbulence. The study analyzed wave breaking through laboratory tests using wave gauges and an acoustic Doppler velocimeter. Fifteen wave conditions were tested in a wave channel with a variable slope bottom profile designed to induce breaking. Timeseries and spectral analysis of free surface elevation data provided insights into wave propagation and breaking behavior under different conditions. Empirical formulations were also evaluated based on the experimental results.
This document discusses waves and their properties. It defines a wave as the transfer of energy through a medium and lists the key properties of waves including amplitude, wavelength, frequency, and velocity. It describes the main types of waves as mechanical, electromagnetic, and matter waves. Mechanical waves are further divided into transverse and longitudinal waves. Electromagnetic waves include radio waves, microwaves, infrared, visible light, UV rays, X-rays, and gamma rays. The principle of superposition states that when two waves pass through the same medium at the same time, the displacement at any point is the sum of the individual displacements. Constructive interference occurs when waves are in phase, resulting in increased amplitude. Destructive interference is
This document provides an overview of Module 1: Oscillations and Waves. It covers the following topics:
1. Free oscillations, including the definition and characteristics of simple harmonic motion, the differential equation of motion, mechanical oscillations using a mass-spring system, and complex notation.
2. Damped and forced oscillations, including the theory of damped oscillations involving overdamping, critical damping, and underdamping. It also discusses forced oscillations and resonance.
3. Shock waves, including definitions of Mach number, properties and laws governing shock waves, and applications involving shock tube experiments.
4. The document concludes with references on oscillations, vibrations, and waves from various textbooks and journals
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1. PRINCIPLES FOR CAPTURE OF ENERGY FROM OCEAN WAVES.
PHASE CONTROL AND OPTIMUM OSCILLATION.
J. Falnes
Department of Physics, NTNU, N-7034 Trondheim, Norway
1. Absorption of waves means generation of waves.
A body oscillating in water will produce waves. A big body and a small body may
produce equally large waves provided the smaller body oscillates with larger amplitude. This
may be utilised for the purpose of wave energy conversion, for instance by a small floating
body heaving in response to an incident wave, in particular so if it can be arranged that the
body oscillates with a larger amplitude than the wave amplitude.
Generally it can be said that a good wave absorber must be a good wave-maker.1
Hence, in order to absorb wave energy it is necessary to displace water in an oscillatory
manner and with correct phase (timing). This can be obtained by an oscillating body as
explained above. Alternatively, wave generation by oscillatory displacement of water can be
obtained, for instance, by an oscillating water column (OWC) in a fixed chamber having an
opening into the sea. It is also possible to enclose the water by blocking the chamber opening
with an elastic or flexible bag, which can oscillate under wave action. In such a case sea water
in the chamber is not necessary; it can simply be replaced by air in which the pressure
oscillates in step with the motion of the flexible bag.
Absorbing wave energy for conversion means that energy has to be removed from the
waves. Hence there must be a cancellation or reduction of waves which are passing the
energy-converting device or are being reflected from it. Such a cancellation or reduction of
waves can be realised by the oscillating device, provided it generates waves which oppose (are
in counter-phase with) the passing and/or reflected waves. In other words, the generated wave
has to interfere destructively with the other waves. This explains the paradoxical, but general
statement that “to destroy a wave means to create a wave”. An illustrative example, where 100
% absorption of wave energy is possible, is shown in figure 1. This corresponds to an infinite
line (perpendicular to the figure) of oscillating small floating bodies, evenly interspaced a
short distance (shorter than one wavelength). Complete absorption of the incident wave
energy is possible also with an elongated body, of cross section as shown in figure 1, and
aligned perpendicular to the plane of the figure, provided the body oscillates vertically and
horizontally in an optimum manner.
It can be shown theoretically2,3,4 that only 50 % absorption is possible if there is only
the symmetrical radiated wave, as shown by the curve b in figure 1, when the wave is
generated by a symmetrical body oscillating in only one mode of motion, the vertical (heave)
oscillation. Likewise, if there is only the antisymmetric radiated wave (curve c) from the
symmetric body, more than 50 % absorption is theoretically impossible. However, if a
sufficiently non-symmetric body is oscillating in only one mode of motion, it may have the
ability to absorb almost all the incident wave energy. Salter had come rather close to this ideal
condition with his experiments on the Duck.5
1
2. Figure 1. To absorb waves means to generate waves. Curve a represents an undisturbed incident
wave. Curve b illustrates symmetric wave generation (on otherwise calm water) by means of
a straight array of, evenly spaced, small floating bodies oscillating in heave (up and down).
Curve c illustrates antisymmetric wave generation. Curve d, which represents the
superposition (sum) of the above three waves, illustrates complete absorption of the incident
wave energy.1
Another example is shown in figure 2. Here a heaving point absorber, absorbing wave
energy, has to radiate circular waves which interfere destructively with the incident plane
wave. A “point absorber”, which may be a heaving body, is (by definition6) of very small
extension compared to the wavelength. The maximum energy which may be absorbed by a
heaving axi-symmetric body equals2,3,6 the wave energy transported by the incident wave
front of width equal to the wavelength divided by 2π. This width may be termed the
“absorption width”. Early experimenters, not being aware of this relationship, were surprised
by measuring absorption widths larger than the physical width of a tested point-absorber
model. An alternative term to absorption width is “capture width”, which we shall use for the
smaller width corresponding to the useful energy, which is the absorbed energy minus energy
lost by friction and other dissipative effects.
Figure 2. Wave pattern of two interfering waves seen from above. When a “point absorber” absorbs
energy from an incident wave, it generates a circular wave radiating away from the
absorber’s immersed surface.
2
3. 2. Optimum oscillation for maximum energy capture.
In order to obtain maximum energy from the waves it is necessary to have optimum
oscillation of the wave-energy converter (WEC). For a sinusoidal incident wave there is an
optimum phase and an optimum amplitude for the oscillation.1
To illustrate this, let us once more refer to figure 1. In this case the amplitudes of the
radiated waves (curves b and c) have to be exactly half of the amplitude of the incident wave
(curve a). Thus it is required that the amplitudes of the vertical and horizontal oscillations of
the WEC have proper values. Note that these optimum amplitudes are proprtional to the
amplitude of the incident wave.
Moreover, with optimum phase conditions for the two modes of oscillation, the two
corresponding waves radiated towards right have to have the same phase (that is: coinciding
wave crests and coinciding wave troughs). This also means that the symmetric and
antisymmetic radiated waves cancel each other towards left. Furthermore, the phases of the
two oscillations have to be correct with respect to the phase of the incident wave, since the
crests of the waves radiated towards right (curves b and c) must coincide with the troughs of
the incident wave (curve a).
For a case with only one mode of oscillation, such as heave, the resulting wave
corresponds to the superposition (sum) of the waves a and b in figure 1. Then the optimum
heave (vertical) amplitude and phase are the as above, in the case of two modes. The wave
radiated towards left and the resulting wave transmitted towards right both have amplitude
equal to half of the amplitude of the incident wave. Since wave energy is proportional to the
square of the wave amplitude this means that 25 % of the incident wave energy is reflected
towards left, and also 25% of it is transmitted towards right. The remaining 50 % is absorbed
by the WEC, and this is the theoretical maximum, as mentioned previously.
A one-mode oscillating system happens to have the optimum phase condition if it is at
resonance with the wave. That means that the wave frequency (reciprocal of the period) is the
same as the natural frequency of the oscillating system. Then the oscillatory velocity of the
system is in phase with the wave’s exciting force which acts on the system. This is illustrated
by comparing the curves a and b in figure 3.
The optimum phase condition is approximately satisfied also for wave frequencies
slightly off resonance, namely for frequencies within the so-called resonance bandwidth of the
system. WECs of very large geometrical extension have broad bandwidths. In order to save
materials (concrete, steel, etc.) it is desirable to utilise a WEC system of smaller physical size.
A drawback with this is that the resonance bandwidth becomes rather narrow.
Thus for small-sized WECs it is very important to apply some form of phase control,
in order to obtain the optimum phase condition, at least approximately. Phase control by
latching is illustrated by curve c in figure 3. (It is assumed that the various floating bodies
considered in figure 3 have equal water plane areas. But the heavier body has deeper draught.)
As mentioned and explained above, there is also an optimum oscillation amplitude in
order for the WEC to absorb a maximum amount of energy. A somewhat smaller amplitude is
required to maximise the converted useful energy, which is the absorbed energy minus some
unavoidable lost energy (due to friction, viscosity, etc). Except for cases with small or rather
moderate wave heights, this desirable amplitude may not be achievable due to the limited
design amplitude of the WEC. In practice, the energy-handling capacity of the WEC’s
machinery and other equipment is also limited. For economic reasons the WEC ought to be
designed with specifications in such a way that it works close to its design limit a rather large
fraction of its life time.7,8 As a consequence much of the wave energy remains in the ocean,
except during time spans of rather moderate wave activity.
3
4. Also for the case when the oscillation amplitude is limited by design specification, the
absorbed energy, as well as the converted useful energy, is maximum when the oscillatory
velocity is in phase with the exciting force due to the incident wave.
3. Phase control by latching.
In order to obtain the optimum oscillatory motion for maximising the absorbed energy
or the converted useful energy it may be necessary to return some energy back into the sea
during some small fractions of each oscillation cycle and profit from this during the remaining
part of the cycle.9 For this reason “optimum control” of WECs has also been termed “reactive
control”.10 To achieve this in practice it is required to utilise a reversible energy-converting
machinery with very low conversion losses. It could, for instance be a high-efficiency
hydraulic machinery which can work either as a motor or as a pump.11 To realise the
optimum control in practice, a computer with appropriate programme software, and with input
signals from sensors measuring the wave1 and/or the WEC’s oscillatory motion10, is required.
It is also necessary to predict the wave some seconds into the future.12,13
If the wave periods are longer than the WEC’s natural period, optimum phase can, in a
simpler way, but only approximately, be obtained by “latching phase control” which provides
for a motion as indicated by curve c of figure 3. A clamping mechanism stops the motion at
the instant of extreme excursion, that is at the instant when the velocity becomes zero. A
release signal is applied to the mechanism a certain time (about one quarter of the natural
period) before the next extremum of the wave exciting force. For a heaving buoy this force is
approximately in phase with the wave elevation of the incident wave. Then the phase control
should provide for the buoy moving upwards/downwards at the occurrence of a wave
crest/trough.
Figure 3. Resonance and phase control. The curves indicate incident wave elevation and vertical
displacement of (different versions of) a heaving body as functions of time.
Curve a: Elevation of the water surface due to the incident wave (at the position of the body). This
would also represent the vertical position of a body with negligible mass. For a body of
diameter very small compared to the wavelength, curve a also represents the wave’s heave
exciting force on the body.
Curve b: Vertical displacement of heaving body whose mass is so large that its natural period is
equal to the wave period (resonance).
Curve c: Vertical displacement of body with smaller mass, and hence shorter natural period. Phase
control is then obtained by keeping the body in a fixed vertical position during certain time
intervals.1
4
5. A mathematical simulation study14 has been carried out on a scaled-down laboratory
model of an OWC placed at the vertical end wall of a 0.4 m wide and 0.7 m deep wave
channel. The width of the OWC is 0.18 m, and the rectangular area of the inner water plane
and of the entrance mouth is 0.22 m2. The upper edge of the mouth is at a depth 0.06 m. For a
situation where the incident wave is sinusoidal with period 2 s, the oscillation of the OWC is
as shown figure 4a without phase control and in figure 4b with latching phase control. It is
seen that the excursion amplitude is significantly larger with control.
While a fairly close approach to the optimum phase is attained by the method of
latching phase control, the amplitude may be less than optimum, because with this method
there is no reversible energy-converting machinery to return desirable amounts of energy back
to the sea during fractions of the oscillation cycle. This drawback is not, however, applicable
with wave conditions where the WECs have to operate at its design amplitude, anyhow.
For the above-mentioned simulation study,14 where amplitude limitation does not
come into play, the energy absorbed is as shown by the curves in figure 5 for the three cases:
no control, latching phase control, and full optimum control. For the latter case it is seen that
relatively large amounts of energy have to be returned to the sea during two intervals of each
oscillation cycle. The theoretical result is that, in the long run, the energy absorbed is about
twice the absorbed energy with latching phase control. And this latter energy is about four
times as much as without any control.
For real sea waves the time intervals between crests and troughs vary in a somewhat
stochastic manner. With operation of a latching-controlled WEC in such irregular (non-
sinusoidal) waves the release signal is determined by a computer with appropriate software. It
is required to feed the computer by input signals from sensors measuring the wave or the wave
exciting force. It is necessary that the computer is able to provide a reasonable prediction of
the wave force a certain time into the future. Evidently, the decision to unlatch the WEC
should be taken at least one quarter natural period before the next extremum of the wave
force.
The principle of latching phase control of a heaving (vertically oscillating) body in
irregular waves, is illustrated by the experimental results shown in figure 6. The experiment
was run in a large laboratory wave channel, 10.5 m wide and 10 m deep. In this particular case
the body was shaped as a cone pointing downwards. A piston pump inside the body was
activated by the heave motion. Through a long rod the piston was connected to a universal
joint on an anchor at the bottom of the wave channel. The cylinder of the pump was rigidly
tied to the body and moved up and down together with it. Through the heave motion energy
was directed through the pump and further through valves and a turbin to become useful
mechanical energy on a rotating shaft. The hydraulically operated latching mechanism
(functioning as a parking brake) could latch the body to the piston rod. Latching and
unlatching signals were provided through a computer fed with signals from sensors measuring
the body’s heave motion and the wave beside the body. The height of the conical body was
2.3 m. With the body in its equilibrium position, the uppermost end of the body, where the
diameter was 0.9 m, was 0.62 m above still water level. The rod diameter was 75 mm. The
body had a mass 120 kg and a volume 0.5 m3. The natural period of the body was about 1.0 s.
5
6. Figure 4. Vertical oscillation of OWC without (upper diagram) and with latching phase control
(lower diagram). The thinner curve represents the incident wave (approximately in phase
with the exciting force) and the thicker curve the ocillating position. Units are metres on the
vertical scale and seconds on the horizontal. The right-hand vertical bar indicates the
occurrence of a force maximum, and the left-hand bar the occurrence of a maximum in
oscillation velocity. In the case of phase control these occurrences coincide. Then the velocity
is in phase with the force, and consequently the overall oscillation excursion becomes larger.
Figure 5. Absorbed energy without phase control (lower broken curve), with latching phase control
(fully drawn curve) and with theoretically ideal optimum control (broken wavy curve). The
curves show the wave energy (in joule) accumulated during 5 seconds.
6
7. Figure 6. Measurements during 25 seconds of an experimental run with a latching-controlled
heaving buoy in an irregular incident wave.15
a. Two different measurements of the wave abreast the buoy.
Fully drawn line: Surface elevation (in m) measured by a two-wire probe.
Dotted line: Hydrodynamic pressure (in 104 N/m2) measured by a pressure transducer placed
0.70 m below the mean water surface.
b. Wave elevation and heave position (both in m).
c. Hydrodynamic pressure (in 103 N/m2) and heave velocity (in m/s).
d. Energy input to piston pump (in J). The average slope of the curve corresponds to a power
input 60 W.
7
8. With the results shown in figure 6, the average period of the irregular wave is at least
3 s, and thus significantly longer than the natural period. It seems that latching and unlatching
occur roughly at right instants, although figure 6b indicates that the latchings occurring at
times 6 and 21 s are slightly too late. Figure 6c reveals that the velocity had maximum slightly
before the wave at 2 and 9 s and slightly after at 12 and 22 s. This indicates slight inaccuracy
in some of the unlatching instants. Figure 6d shows how the accumulated energy is built up
when the body moves with proper phase. By and large, a successful phase control was
obtained in the experiment.
References
1 Falnes, J. and Budal, K. (1978). Wave power conversion by point absorbers.
Norwegian Maritime Research, Vol.6, No.4, pp. 2-11
2 Evans, D.V. (1976). A theory for wave-power absorption by oscillating bodies.
Journal of Fluid Mechanics, 77, pp. 1-25.
3 Newman, J.N. (1976). The interaction of stationary vessels with regular waves. Proc.
11th Symposium on Naval Hydrodynamics, London, pp. 491-501.
4 Mei, C.C. (1976). Power extraction for water waves. Journal of Ship Research,
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