Author: Florian Ion Petrescu
Publisher: BoD – Books on Demand
ISBN: 3848229900
Category : Science
Languages : en
Pages : 82
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Book Description
The Doppler effect (or Doppler shift), named after Austrian physicist Christian Doppler who proposed it in 1842 in Prague, is the change in frequency of a wave for an observer moving relative to the source of the wave. It is commonly heard when a vehicle sounding a siren or horn approaches, passes, and recedes from an observer. The received frequency is higher (compared to the emitted frequency) during the approach, it is identical at the instant of passing by, and it is lower during the recession. The relative changes in frequency can be explained as follows. When the source of the waves is moving toward the observer, each successive wave crest is emitted from a position closer to the observer than the previous wave. Therefore each wave takes slightly less time to reach the observer than the previous wave. Therefore the time between the arrival of successive wave crests at the observer is reduced, causing an increase in the frequency. While they are travelling, the distance between successive wave fronts is reduced; so the waves \\\\\\\"bunch together\\\\\\\". Conversely, if the source of waves is moving away from the observer, each wave is emitted from a position farther from the observer than the previous wave, so the arrival time between successive waves is increased, reducing the frequency. The distance between successive wave fronts is increased, so the waves "spread out". For waves that propagate in a medium, such as sound waves, the velocity of the observer and of the source is relative to the medium in which the waves are transmitted. The total Doppler Effect may therefore result from motion of the source, motion of the observer, or motion of the medium. Each of these effects is analyzed separately. For waves which do not require a medium, such as light or gravity in general relativity, only the relative difference in velocity between the observer and the source needs to be considered.
Author: Florian Ion Petrescu
Publisher: Createspace Independent Pub
ISBN: 9781469948829
Category : Science
Languages : en
Pages : 72
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Book Description
The Doppler effect (or Doppler shift), named after Austrian physicist Christian Doppler who proposed it in 1842 in Prague, is the change in frequency of a wave for an observer moving relative to the source of the wave. It is commonly heard when a vehicle sounding a siren or horn approaches, passes, and recedes from an observer. The received frequency is higher (compared to the emitted frequency) during the approach, it is identical at the instant of passing by, and it is lower during the recession. The relative changes in frequency can be explained as follows. When the source of the waves is moving toward the observer, each successive wave crest is emitted from a position closer to the observer than the previous wave. Therefore each wave takes slightly less time to reach the observer than the previous wave. Therefore the time between the arrival of successive wave crests at the observer is reduced, causing an increase in the frequency. While they are travelling, the distance between successive wave fronts is reduced; so the waves "bunch together." Conversely, if the source of waves is moving away from the observer, each wave is emitted from a position farther from the observer than the previous wave, so the arrival time between successive waves is increased, reducing the frequency. The distance between successive wave fronts is increased, so the waves "spread out." For waves that propagate in a medium, such as sound waves, the velocity of the observer and of the source is relative to the medium in which the waves are transmitted. The total Doppler Effect may therefore result from motion of the source, motion of the observer, or motion of the medium. Each of these effects is analyzed separately. For waves which do not require a medium, such as light or gravity in general relativity, only the relative difference in velocity between the observer and the source needs to be considered. The Doppler Effect [1-3] represents the frequency variation of the waves, received by an observer which is drawing (coming), respectively it's removing (going), from a wave spring (source). If a bright spring is drawing to an observer, the frequency of waves received by the observer is bigger than the emitted frequency of source, such that the respective spectral lines are moving to violet. On the contrary, if the light source is removing from the observer, the spectral lines are moving to red. One proposes to study the Doppler Effect for the light waves, generally for the electromagnetic waves.
Author: David D. Nolte
Publisher: Oxford University Press
ISBN: 0192528505
Category : Science
Languages : en
Pages : 384
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Book Description
Galileo Unbound traces the journey that brought us from Galileo's law of free fall to today's geneticists measuring evolutionary drift, entangled quantum particles moving among many worlds, and our lives as trajectories traversing a health space with thousands of dimensions. Remarkably, common themes persist that predict the evolution of species as readily as the orbits of planets or the collapse of stars into black holes. This book tells the history of spaces of expanding dimension and increasing abstraction and how they continue today to give new insight into the physics of complex systems. Galileo published the first modern law of motion, the Law of Fall, that was ideal and simple, laying the foundation upon which Newton built the first theory of dynamics. Early in the twentieth century, geometry became the cause of motion rather than the result when Einstein envisioned the fabric of space-time warped by mass and energy, forcing light rays to bend past the Sun. Possibly more radical was Feynman's dilemma of quantum particles taking all paths at once — setting the stage for the modern fields of quantum field theory and quantum computing. Yet as concepts of motion have evolved, one thing has remained constant, the need to track ever more complex changes and to capture their essence, to find patterns in the chaos as we try to predict and control our world.
Author: Victor C. Chen
Publisher: Artech House
ISBN: 1608070581
Category : Science
Languages : en
Pages : 309
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Book Description
The Doppler Effect can be thought of as the change in frequency of a wave for an observer moving relative to the source of the wave. In radar, it is used to measure the velocity of detected objects. This highly practical resource provides thorough working knowledge of the micro-Doppler effect in radar, including its principles, applications and implementation with MATLAB codes. The book presents code for simulating radar backscattering from targets with various motions, generating micro-Doppler signatures, and analyzing the characteristics of targets. In this title, professionals will find detailed descriptions of the physics and mathematics of the Doppler and micro-Doppler effect. The book provides a wide range of clear examples, including an oscillating pendulum, a spinning and precession heavy top, rotating rotor blades of a helicopter, rotating wind-turbine blades, a person walking with swinging arms and legs, a flying bird, and movements of quadruped animals.
Author: Matthew E. Cross
Publisher: Cambridge University Press
ISBN: 1107615887
Category : Medical
Languages : en
Pages : 439
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Book Description
A quick reference to basic science for anaesthetists, containing all the key information needed for FRCA exams.
Author: T.P. Gill
Publisher:
ISBN:
Category :
Languages : en
Pages : 160
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Book Description
Author: Rune Aaslid
Publisher: Springer Science & Business Media
ISBN: 3709188644
Category : Medical
Languages : en
Pages : 187
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Book Description
Every few years a dissertation comes to the area of clinical application of medical technology which carries us forward as on a magic carpet into new regions of understanding and patient care. This book is such a magic carpet. It brings together, in a clear and incisive fashion, important hemodynamic principles with a simple noninvasive method of application to a part of the cerebral vasculature which has been relatively inaccessible. To the lucky and perceptive person who reads this book, a feeling of excitement and hope for progress is engendered. The diligent application of the potentials of transcranial Doppler ultrasound brings new power to our efforts in understanding the cerebral circulation and the causes, treatment and prevention of cerebrovascular disorders. Merrill P. Spencer, M. D. Director Institute of Applied Physiology and Medicine Seattle, Wash. , July 1986 Acknowledgements I am greatly indebted to Prof. He1ge Nornes, Oslo, who introduced me to the fascinating study of cerebral hemodynamics in the early 1970's and since then continually encouraged my interest in this field. It was through his pioneering work on the cerebral circulation-using peroperative electromagnetic flowmetry and Doppler techniques-that the basis was laid for the noninvasive trans cranial approach to the circle of Willis described in this book. I also gratefully acknowledge the stimulating case discussions with Prof. Peter Huber, Berne, at the very early introduction of trans cranial Doppler, the inspiring exchange of ideas with Dr. Merrill P.
Author: Jørgen Arendt Jensen
Publisher: Cambridge University Press
ISBN: 9780521464840
Category : Medical
Languages : en
Pages : 344
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Book Description
A clear, extensively illustrated treatment of ultrasound systems used in estimating blood velocities.
Author: Victor C. Chen
Publisher: Artech House
ISBN: 1630815489
Category : Technology & Engineering
Languages : en
Pages : 370
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Book Description
Written by a prominent expert in the field, this updated and expanded second edition of an Artech House classic includes the most recent breakthroughs in vital sign and gender recognition via micro-radar, as well as covering basic principles of Doppler effect and micro-Doppler effect and describing basic applications of micro-Doppler signatures in radar. The book presents detailed procedures about how to generate and analyze micro-Doppler signatures from radar signals. Readers will learn how to model and animate an object (such as human, spinning top, rotating rotor blades) with movement, simulation of radar returns from the object, and generating micro-Doppler signature. The book includes coverage of the Google project “Soli”, which demonstrated the use of radar micro-Doppler effect to sense and recognize micro motions of human hand gesture for controlling devices. It also discusses noncontact detection of human vital sign (micro motions of breathing and heart beating) using radar, another important application of radar micro-Doppler sensors. Detailed MATLAB source codes for simulation of radar backscattering from targets with various motions are provided, along with source codes for generating micro-Doppler signatures and analyzing characteristics of targets.
Author: Dan Fullerton
Publisher: Silly Beagle Productions
ISBN: 0983563306
Category : Education
Languages : en
Pages : 300
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Book Description
APlusPhysics: Your Guide to Regents Physics Essentials is a clear and concise roadmap to the entire New York State Regents Physics curriculum, preparing students for success in their high school physics class as well as review for high marks on the Regents Physics Exam. Topics covered include pre-requisite math and trigonometry; kinematics; forces; Newton's Laws of Motion, circular motion and gravity; impulse and momentum; work, energy, and power; electrostatics; electric circuits; magnetism; waves; optics; and modern physics. Featuring more than five hundred questions from past Regents exams with worked out solutions and detailed illustrations, this book is integrated with the APlusPhysics.com website, which includes online question and answer forums, videos, animations, and supplemental problems to help you master Regents Physics essentials. "The best physics books are the ones kids will actually read." Advance Praise for APlusPhysics Regents Physics Essentials: "Very well written... simple, clear engaging and accessible. You hit a grand slam with this review book." -- Anthony, NY Regents Physics Teacher. "Does a great job giving students what they need to know. The value provided is amazing." -- Tom, NY Regents Physics Teacher. "This was tremendous preparation for my physics test. I love the detailed problem solutions." -- Jenny, NY Regents Physics Student. "Regents Physics Essentials has all the information you could ever need and is much easier to understand than many other textbooks... it is an excellent review tool and is truly written for students." -- Cat, NY Regents Physics Student
