An Ultrasonic Through-Wall Communication (UTWC) System Model

2013 ◽  
Vol 135 (1) ◽  
Author(s):  
Sebastian Roa-Prada ◽  
Henry A. Scarton ◽  
Gary J. Saulnier ◽  
David A. Shoudy ◽  
Jonathan D. Ashdown ◽  
...  
Keyword(s):  
Communication Channel ◽  
Solid Wall ◽  
Circuit Simulation ◽  
Ultrasonic Waves ◽  
Ultrasonic Transducers ◽  
Sensor Data ◽  
Ultrasonic Power ◽  
Concurrent Simulation ◽  
Electronic Circuit Simulation ◽  
Solid Walls

Ultrasonic waves at 1 MHz are used to send information across solid walls without the needs for through wall penetrations. A communication channel is established by attaching a set of three ultrasonic transducers to the wall. The first transducer transmits a continuous ultrasonic wave into the wall. The second transducer is mounted on the opposite side of the wall (inside) and operates as a receiver and signal modulator. The third transducer, the outside receiving transducer, is installed on the same side as the first transducer where it is exposed to the signal reflected from the blended interface of the inside wall and inside transducer. Inside sensor data is digitized and the bit state is used to vary in time the electrical load connected to the inside transducer, changing its acoustic impedance in accordance with each data bit. These impedance changes modulate the amplitude of the reflected ultrasonic signal. The modulated signal is detected at the outside receiving transducer, where it is then demodulated to recover the data. Additionally, some of the ultrasonic power received at the inside transducer is harvested to provide energy for the communication and sensor system on the inside. The entire system (ultrasonic, solid wall, and electronic) is modeled in the electrical domain by means of electro-mechanical analogies. This approach enables the concurrent simulation of the ultrasonic and electronic components. A model of the communication system is implemented in an electronic circuit simulation package, which assisted in the analysis and optimization of the communication channel. Good agreement was found between the modeled and experimental results.

Modeling of an Ultrasonic Communication System

2007 ◽  
Author(s):  
S. Roa-Prada ◽  
H. A. Scarton ◽  
G. J. Saulnier ◽  
D. A. Shoudy ◽  
J. D. Ashdown ◽  
...  
Keyword(s):  
Communication System ◽  
Communication Channel ◽  
Solid Wall ◽  
Circuit Simulation ◽  
Electrical Power ◽  
Electric Circuit ◽  
Acoustic Power ◽  
Ultrasonic Transducers ◽  
Electronic Components ◽  
Metallic Wall

This paper discusses the use of ultrasound to convey data from one side of a metallic wall to the other side. A communication channel is established by attaching a set of three ultrasonic transducers to the wall. The first transducer injects a continuous ultrasonic wave into the wall. The second transducer is mounted on the inside and operates as a receiver and signal modulator. The third transducer is installed on the same side as the first transducer and receives the signal that is reflected from the inside transducer. A sensor on the inside provides analog data that is then digitized. The digitized bits are used to vary the electrical load applied to the electrical terminals of the inside transducer, changing its acoustic impedance in accordance with the data bits. The impedance changes, in turn, modulate the amplitude of the reflected ultrasonic signal. This modulated signal is detected at the outside receiving transducer, where it is then demodulated to recover the data. Additionally, some of the acoustic power received at the inside transducer is harvested to produce the electrical power needed to operate the communication and sensor system on the inside. The entire system (ultrasonic, solid wall, and electronic) is modeled in the electrical domain through electro-mechanical analogies. This approach enables the simultaneous examination of the ultrasonic and electronic components. The electric circuit simulation package PSpice is used to simulate the communication system, which assisted in the analysis and optimization of the communication channel. Both simulation and experimental results are presented and discussed.

scholarly journals Hydrodynamic Boundary Layers at Solid Wall—A Tool for Separation of Fine Solids

2021 ◽  
Vol 5 (1) ◽  
pp. 11
Author(s):  
Ljubomir Nikolov
Keyword(s):  
Relative Density ◽  
Hydrodynamic Interaction ◽  
Theoretical Study ◽  
Solid Wall ◽  
Separation Processes ◽  
Starting Point ◽  
Potential Applications ◽  
Neutrally Buoyant ◽  
Solid Walls ◽  
Solid Spheres

A theoretical study is performed about the hydrodynamic interaction of fine species entrapped in the boundary layer (BL) at solid wall (plate). The key starting point is the analysis of the disturbance introduced by solid spheres in the background fluid flow. For a neutrally buoyant entity, the type of interaction is determined by the size of the spheres as compared to the thickness of the BL region. The result is granulometric separation of the solids inside the BL domain at the wall. The most important result in view of potential applications concerns the so-called small particles Rp < L/ReL5/4 (ReL is the Reynolds number of the background flow and Rp is the radius of the entrapped sphere). In the case of non-neutrally buoyant particles, gravity interferes with the separation effect. Important factor in this case is the relative density of the solid species as compared to this of the fluid. In view of further practical uses, particles within the range of Δρ/ρ < Fr2/ReL1/2 (Fr is Froude number and Δρ/ρ is the relative density of the entrapped solids) are systematically studied. The trajectories inside the BL region of the captured species are calculated. The obtained data show that there are preferred regions along the wall where the fine solids are detained. The results are important for the assessment of the general efficiency of entrapment and segregation of fine species in the vicinity of solid walls and have high potential for further design of industrial separation processes.

A Molecular Dynamics Study on Effects of Nanostructural Clearances at an Interface on Thermal Resistance

2008 ◽  
Author(s):  
Masahiko Shibahara ◽  
Kosuke Inoue ◽  
Kiyomori Kobayashi
Keyword(s):  
Molecular Dynamics ◽  
Temperature Gradient ◽  
Thermal Resistance ◽  
Solid Wall ◽  
Middle Layer ◽  
Dynamics Simulation ◽  
Nanometer Scale ◽  
Liquid Density ◽  
Solid Interface ◽  
Solid Walls

The classical molecular dynamics simulation was conducted in order to clarify the effects of structural clearances in nanometer scale on thermal resistance at a liquid-solid interface. A liquid molecular region confined between the solid walls, of which the interparticle potential was Lennard-Jones type, was employed as a calculation system. The solid walls consisted of three atomic layers where the temperature of the middle layer was controlled by the Langevin method. Heat flux in the system was calculated numerically by integrating the forces that acted on the temperature controlled atoms by the Langevin method. The temperature jump between the solid wall and the liquid molecular region was calculated numerically. The thermal resistance at a liquid-solid interface was calculated numerically with changing the surface structural clearances in nanometer scale. Temperature gradient and liquid density were also changed as calculation parameters. With changing the surface structural clearances from 0nm to 2.5nm the thermal resistance at the interface once decreased and became the minimum value when the structural clearances were between 0.6 to 1.0 nm. The thermal resistance between the solid and the liquid increased when the structural clearances were more than 1.0nm. With the increase of the liquid density the thermal resistance between the solid and the liquid substantially decreased regardless of the temperature gradient and the surface structures in nanometer scale.

Infrared Thermal Image on Vapor-Liquid Interface in Capillary Microgrooves Heat Sink

2009 ◽  
Author(s):  
Tao Wang ◽  
Xuegong Hu ◽  
Dawei Tang ◽  
Chaohong Guo
Keyword(s):  
Temperature Distribution ◽  
Heat Sink ◽  
Solid Wall ◽  
Thermal Image ◽  
Liquid Interface ◽  
Liquid Interfaces ◽  
Average Temperature ◽  
Solid Walls ◽  
Working Liquid ◽  
Vapor Liquid

An infrared thermoviewer is utilized to measure the temperature distribution on solid walls and vapor-liquid interfaces of the rectangular capillary microgrooves heat sink, which is made of borosilicate glass. The infrared thermal image clearly shows that the solid wall temperature of microgroove top is lower than the average temperature of vapor-liquid interface. The results indicate that heat source position has a significant influence on the microgrooves surface temperature distribution, besides working liquid, tilt angle (the angle between microgroove surface and gravity direction) and heat flux.

scholarly journals A New Four-Scroll Chaotic System with a Self-Excited Attractor and Circuit Implementation

2018 ◽  
Vol 7 (3) ◽  
pp. 1931 ◽  
Author(s):  
Sivaperumal Sampath ◽  
Sundarapandian Vaidyanathan ◽  
Aceng Sambas ◽  
Mohamad Afendee ◽  
Mustafa Mamat ◽  
...  
Keyword(s):  
Chaotic System ◽  
Chaotic Systems ◽  
Electronic Circuit ◽  
Circuit Simulation ◽  
Equilibrium Points ◽  
Phase Portraits ◽  
Chaotic Model ◽  
New Chaotic System ◽  
Electronic Circuit Simulation ◽  
New System

This paper reports the finding a new four-scroll chaotic system with four nonlinearities. The proposed system is a new addition to existing multi-scroll chaotic systems in the literature. Lyapunov exponents of the new chaotic system are studied for verifying chaos properties and phase portraits of the new system via MATLAB are unveiled. As the new four-scroll chaotic system is shown to have three unstable equilibrium points, it has a self-excited chaotic attractor. An electronic circuit simulation of the new four-scroll chaotic system is shown using MultiSIM to check the feasibility of the four-scroll chaotic model.

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