Diffraction of electromagnetic waves by ultrasonic waves in an anisotropic medium. I

1967 ◽  
Vol 9 (1) ◽  
pp. 7-19
Author(s):  
V. S. Il'in ◽  
G. P. Kostyunina
Keyword(s):  
Anisotropic Medium ◽  
Electromagnetic Waves ◽  
Ultrasonic Waves

DESIGN, CONSTRUCTION AND TESTING OF A SMART STATIC AND DYNAMIC OBSTACLE WALKING STICK WITH EMF DETECTOR FOR THE BLINDS USING MCU AND CONTROLLING SOFTWARE

2021 ◽  
Vol 5 (2) ◽  
pp. 334-343
Author(s):  
Sani Abdullahi Adamu ◽  
Abdulkarim Adamu ◽  
M. S. Anas
Keyword(s):  
Electromagnetic Waves ◽  
Ultrasonic Waves ◽  
Project Work ◽  
Electrical Safety ◽  
Blind People ◽  
Visually Challenged ◽  
Dynamic Obstacle ◽  
Walking Stick ◽  
Modern Technologies ◽  
Design Construction

Smart static and dynamic obstacle walking stick with EMF detector is an upgraded smart stick designed for blind people for optimal navigation and electrical safety.  An advanced blind stick prototype that allows visually challenged people to navigate walking paths and identify electronic gadgets with ease using modern technologies is hereby developed. The blind stick is integrated with ultrasonic sensor along with an EMF detector. This prototype first uses ultrasonic sensors to sense obstacles ahead using ultrasonic waves. On sensing obstacles, the sensor directs this data to the microcontroller. The microcontroller then processes this data and examine if the obstacle is close enough. If the obstacle is not that close the circuit does nothing. If the obstacle is close the microcontroller sends a signal to sound a buzzer. One more feature is that it allows the blind to detect the presence of EMF (electromagnetic field/electromagnetic waves) in the region he/she is, if there is, the microcontroller also sends a signal to a vibration motor (i.e. the output is in form of vibration), and if otherwise, the circuit does not trigger and thus, the vibration motor does nothing. The results obtained from the measurements have shown that this project work is optimally working and indeed operative.

Head-Up Display System for Closed Circuit Rebreathers With Antimagnetic Wireless Data Transmission

2013 ◽  
Vol 47 (6) ◽  
pp. 42-51
Author(s):  
Arne Sieber ◽  
Andreas Schuster ◽  
Sebastian Reif ◽  
Dennis Madden ◽  
Peter Enoksson
Keyword(s):  
Data Transmission ◽  
Electromagnetic Waves ◽  
Sea Water ◽  
Low Frequency ◽  
Ultrasonic Waves ◽  
Limited Information ◽  
Wireless Data ◽  
Wireless Data Transmission ◽  
Field Of Vision ◽  
European Standards

AbstractRebreather divers use LED-based head-up displays (HUD) as a primary display and warning device for the partial pressure of O2 in the breathing loop. Such devices are usually mounted on the mouthpiece of the rebreather in the field of vision of the diver. LED-based HUDs are simple devices and can be designed so that they are easy to understand but have limited information content. Few alphanumeric or graphical screen-based HUDs have been developed in the past. Connecting such a device to a rebreather requires cable links, which divers dislike, and increases the risk of entanglement. State-of-the-art wireless data transmission uses ultrasonic waves or low-frequency electromagnetic waves; the former is not silent, and the latter achieves only very low data transmission rates of a few bytes per second and does not meet the antimagnetic standards required by military divers. The present paper describes a novel HUD system that incorporates a simple LED-based primary HUD along with an advanced secondary head-up diving computer with a micro organic LED screen. An optical infrared data transmission system is used to transmit all rebreather relevant data from the primary to the secondary device. One prototype of the system was manufactured and successfully tested in the laboratory according to relevant European standards as well as during several dives in fresh and sea water.

Polarization modulation of electromagnetic waves scattered from a quasi-homogeneous anisotropic medium

2012 ◽  
Vol 14 (12) ◽  
pp. 125705 ◽  
Author(s):  
Jia Li ◽  
Zhaoxia Shi ◽  
Hongliang Ren ◽  
Hao Wen ◽  
Jin Lu ◽  
...  
Keyword(s):  
Anisotropic Medium ◽  
Electromagnetic Waves ◽  
Polarization Modulation ◽  
Homogeneous Anisotropic Medium

scholarly journals Singular polarimetry: Evolution of polarization singularities in electromagnetic waves propagating in a weakly anisotropic medium

2008 ◽  
Vol 16 (2) ◽  
pp. 695 ◽  
Author(s):  
Konstantin Yu. Bliokh ◽  
Avi Niv ◽  
Vladimir Kleiner ◽  
Erez Hasman
Keyword(s):  
Anisotropic Medium ◽  
Electromagnetic Waves

A history of ultrasound in obstetrics and gynaecology

2011 ◽  
Author(s):  
Stuart Campbell
Keyword(s):  
Electromagnetic Waves ◽  
Three Dimensional ◽  
Ultrasonic Waves ◽  
Ultrasound Images ◽  
Pulsed Ultrasound ◽  
Obstetrics And Gynaecology ◽  
Abdominal Masses ◽  
Pierre Curie ◽  
History Of ◽  
Electric Effect

It is often difficult to know when most developments in medicine actually begin. They tend to evolve and many people will claim the credit of being the first to make the breakthrough. with ultrasound in obstetrics and gynaecology there is no such doubt for it had a very definite beginning with the 1958 classic Lancet paper by Ian Donald, John McVicar, and Tom Brown ‘The investigation of abdominal masses by pulsed ultrasound’. Actually this is an unfortunate title because it does not identify what was truly unique about the paper which is that it was entirely devoted to ultrasound studies in clinical obstetrics and gynaecology and contained the first ultrasound images of the fetus and also gynaecological masses. The other unique feature was that these were the first images taken with a compound contact scanner which was the first practical scanning machine. It would be short-sighted to write about the development of medical ultrasound without mentioning some of the great scientists of the 19th and 20th centuries whose conceptual advances paved the way for the modern ultrasound machine. Thomas Young in 1801 described ‘phase shifting’ in relation to light waves but this concept is used in ultrasound phased array systems to control interference patterns and is used in the production of three-dimensional (3-D) images. Christian Doppler in 1842 described what we now call the ‘Doppler effect’ in relation to the motion of stars but this principle is now used as the basis for blood flow studies in pelvic vessels and the fetus. Pierre Curie in 1880 described the piezo electric effect whereby mechanical distortion of ceramic crystals would produce an electric charge; the reverse of this effect is used in all transducers to generate ultrasonic waves. Paul Langevin in 1915 built the first hydrophone which used ultrasonic waves to locate the position and distance of submarines and is the principle behind the measurement of the fetus and abdominal masses by ultrasound. The development of Radar by watson-watt and his team using electromagnetic waves in 1943 was later adapted for ultrasound to produce two-dimensional (2-D) images.

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