Determination of Vibrating Structure Patterns Using Acoustic Waves

2008 ◽  
Author(s):  
P. A. Lewin ◽  
W. A. Berger ◽  
C. J. Vecchio ◽  
M. E. Schafer
Keyword(s):  
Acoustic Field ◽  
Acoustic Waves ◽  
Angular Spectrum ◽  
Field Analysis ◽  
Surface Velocity ◽  
Design And Optimization ◽  
Reconstructed Surface ◽  
Ultrasound Applications ◽  
Structure Patterns

The objective of this work was to develop an acoustic field based technique that would be capable of remote sensing and reproduction of vibrating structure patterns. Knowledge of vibrating pattern characteristics is of interest in many applications, including minimization of noise generation in different media and design and optimization of piezoelectric transducers used in diagnostic ultrasound imaging. The technique is based on the angular spectrum method of wave-field analysis, and is applicable to both continuous and wideband pulsed waves. It also allows the effects of acoustic parameters such as absorption, dispersion, refraction, and phase distortion to be accounted for. Examples of remotely reconstructed surface velocity distributions of complex acoustic radiators operating in the low MHz (1–3MHz) range of frequencies will be presented. The examined geometries include single focused and plane axi-symmetric sources and arrays similar to those employed in both diagnostic and therapeutic ultrasound applications. The initial results obtained demonstrate the applicability of the angular spectrum approach and its extension to the analysis of acoustic field propagation through nonlinear liquid media. The method holds particular promise for use as a tool in the design and optimization of acoustic radiators. The ultimate goal of this research is to develop the model useful in optimization of ultrasound transducer performance and providing information on the degradation of transducer performance due to propagation through complex nonlinear media such as biological tissue.

Field analysis Cr(VI) in water samples by a smartphone-based ultralong absorption path reflection colorimetric device

2021 ◽  
Author(s):  
Xiaolan Chen ◽  
Cheng Ma ◽  
Qi Kang ◽  
Yu-Qin Chen ◽  
Dazhong Shen
Keyword(s):  
Hexavalent Chromium ◽  
Water Samples ◽  
Environmental Samples ◽  
Field Analysis ◽  
Absorption Path

Hexavalent chromium is highly toxic and regarded as one of the main pollutants in environmental samples. Sophisticated laboratory instruments are commercially available for in-field determination of chromium. It is highly...

scholarly journals Some indicators of water quality of the Tamis river

2011 ◽  
Vol 17 (1) ◽  
pp. 107-115 ◽  
Author(s):  
Nada Babovic ◽  
Dejan Markovic ◽  
Vojkan Dimitrijevic ◽  
Dragan Markovic
Keyword(s):  
Water Quality ◽  
Ph Value ◽  
Ammonium Nitrogen ◽  
Field Analysis ◽  
Total Hardness ◽  
Chemical Parameters ◽  
Physico Chemical

This paper shows the results obtained in field analysis performed at the Tamis River, starting from the settlement Jasa Tomic - border between Serbia and Romania to Pancevo - confluence of Tamis into the Danube. The Tamis is a 359 km long river rising in the southern Carpathian Mountains. It flows through the Banat region and flows into the Danube near Pancevo. During the years the water quality of the river has severely deteriorated and badly affected the environment and the river ecosystem. In situ measurements enabled determination of physico-chemical parameters of water quality of the Tamis River on every 400 m of the watercourse, such as: water temperature, pH value, electrical conductivity, contents of dissolved oxygen and oxygen saturation. The main reason of higher pollution of Tamis is seen in connection to DTD hydro system. Sampling was performed at 7 points with regard to color, turbidity, total hardness, alkalinity, concentration of ammonium nitrogen, nitrite nitrogen, nitrate nitrogen, iron, chlorides and sulphates in samples. The aim of the present work was to evaluate water quality in the Tamis River taking into account significant pollution, which originates from settlements, industry and agriculture, and to suggest appropriate preventive measures to further pollution decreasing of the river's water.

scholarly journals Automated Insertion of Objects Into an Acoustic Robotic Gripper

Proceedings ◽  
2020 ◽  
Vol 64 (1) ◽  
pp. 40
Author(s):  
Marc Röthlisberger ◽  
Marcel Schuck ◽  
Laurenz Kulmer ◽  
Johann W. Kolar
Keyword(s):  
Acoustic Field ◽  
Acoustic Waves ◽  
Acoustic Pressure ◽  
Pressure Field ◽  
Acoustic Power ◽  
Industrial Applications ◽  
High Density ◽  
Analytical Models ◽  
Acoustic Levitation ◽  
Mechanical Contact

Acoustic levitation forces can be used to manipulate small objects and liquid without mechanical contact or contamination. To use acoustic levitation for contactless robotic grippers, automated insertion of objects into the acoustic pressure field is necessary. This work presents analytical models based on which concepts for the controlled insertion of objects are developed. Two prototypes of acoustic grippers are implemented and used to experimentally verify the lifting of objects into the acoustic field. Using standing acoustic waves and by dynamically adjusting the acoustic power, the lifting of high-density objects (>7 g/cm3) from acoustically transparent surfaces is demonstrated. Moreover, a combination of different acoustic traps is used to lift lower-density objects from acoustically reflective surfaces. The provided results open up new possibilities for the implementation of acoustic levitation in robotic grippers, which have the potential to be used in a variety of industrial applications.

Design and optimization for current transformer core based on magnetic field analysis

2021 ◽  
pp. 1-14
Author(s):  
Guoyong Zhang ◽  
Jing Luo ◽  
Lifu He ◽  
Xiudong Zhou ◽  
Shaosheng Fan
Keyword(s):  
Transmission Lines ◽  
Great Influence ◽  
Current Transformer ◽  
Magnetic Core ◽  
Field Analysis ◽  
Core Material ◽  
Design And Optimization ◽  
Magnetic Field Analysis ◽  
Acquisition Device ◽  
On Line

In order to ensure the safety and reliability of power system, more and more monitoring and maintenance equipment on transmission lines are being used. However, these equipment would not work without the supply of power. At present, the current transformer has been widely used in the on line power acquisition device. As an important part of the current transformer, the performance magnetic core has great influence on the power acquisition. In this paper, the core parameters of the current transformer in the on-line power acquisition device are designed, and the parameters such as core material and air gap length are optimized and verified by simulation as well.

scholarly journals Determination Of Snow Facies and Ice Velocity Using Synthetic Aperture Radar Imagery

1990 ◽  
Vol 14 ◽  
pp. 330-330
Author(s):  
R.A. Bindschadler ◽  
P.L. Vornberger
Keyword(s):  
Synthetic Aperture Radar ◽  
Liquid Water ◽  
Snow Accumulation ◽  
Surface Velocity ◽  
Synthetic Aperture ◽  
Stream Network ◽  
Backscatter Signal ◽  
Volume Scattering ◽  
Aperture Radar

The properties of synthetic aperture radar (SAR) imagery are appropriate for its use to map snow facies. These facies, defined by Benson (1962), are subdivisions of the accumulation area of an ice sheet or polar glacier and represent the interaction of the ice mass with the climate through the processes of snow accumulation and melting. Changes in these climatic parameters are expected to cause changes in the extent and character of these facies. The ability of SAR to discriminate these facies is due to the significant amount of sub-surface volume scattering in the measured radar backscatter signal and the strong absorption of radar energy by liquid water. The amount of volume scattering is dependent on the size and distribution of scatterers in the medium. This dependence varies over the size range of snow grains to ice lenses. Specific examples of the ability to detect different scatterer populations in ice sheets with SAR are shown. Other examples are given to demonstrate the reduction of backscatter signal when liquid water is present.Another important application of SAR data is the determination of surface velocity. Coregistration of a SAR and a TM image spanning an eight-year period was completed for an area in south-western Greenland. The composite image shows that, while the network of surface streams is nearly unchanged, their distance from lakes upstream increased over the eight-year interval between images. Because the lakes are likely fixed in space, a result of surface depressions whose positions are determined by the stationary bedrock topography, the displacement of the stream network was used to calculate a surface velocity of 40 ± 10 m per year near the equilibrium line.

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