Development of Automated Measurement Setup for Characterizing Underwater Acoustic Transducers

2016 ◽  
Vol 50 (6) ◽  
pp. 69-75
Author(s):  
Amirthalingam Malarkodi ◽  
Peddinti SSR Sridhar ◽  
Ganesan Latha
Keyword(s):  
Accurate Determination ◽  
Motion Controller ◽  
Report Generation ◽  
Underwater Acoustic ◽  
Acoustic Transducers ◽  
Acoustic Transducer ◽  
Measurement Results ◽  
Computer Based ◽  
Calibration Program

AbstractAccurate determination of sensitivity and directivity is important for any underwater acoustic transducer. In this work, an automatic measuring platform was designed and implemented for characterizing underwater acoustic transducers. The overall hardware setup includes a PXI (PCI Extensions for Instrumentation)-based data acquisition system, computer-based controller module, motion controller module, and LabVIEW-based automatic calibration program. The system performs a sequence of operations automatically and achieves synchronous control of transmission and acquisition of real-time acoustic signals as well as processing, recording, and report generation. This measurement platform can be utilized for characterizing any type of acoustic transducer for its receiving sensitivity, transmitting response, and directivity measurement as per IEC60565 standard. The measurement results for RESON TC4034 and RESON TC 2080 transducers are presented and the results show that the system is able to carry out accurate calibration and characterization of any underwater acoustic transducer. Sources of uncertainty for calibration are also presented with the confidence level of approximately 95%.

Accurate Measurement on Cross Sectional Area of Single Filaments Using a Desktop SEM

2015 ◽  
Vol 1083 ◽  
pp. 111-117
Author(s):  
Xi Ying Yang ◽  
Ou Yang Ting ◽  
You Qing Fei
Keyword(s):  
Accurate Determination ◽  
Cross Sectional Area ◽  
Morphological Observation ◽  
Sectional Area ◽  
Cross Sectional ◽  
Fiber Properties ◽  
Measurement Results ◽  
Fiber Sample ◽  
Key Parameter

Cross sectional area of single filaments, a key parameter to characterize fiber properties, was experimentally studied using a desktop scanning electron microscope. Three different methods are employed based on the pixel area, averaged diameter and single diameter measurements, respectively. Results have shown that all three methods can achieve accurate measurement results once the axis of fiber sample is kept parallel to the electron beam. Significant errors are generated for the fiber samples with their axis tilted, which may frequently occur as a sample prepared. For circular fibers, a single diameter measured from tilted fibers is sufficient to determine their cross sectional area at high precision with COV values below 1.6%. By selecting an appropriate method, a desktop SEM can serve as a convenient and powerful tool for accurate determination of cross sectional area as well as morphological observation.

scholarly journals Design Flexural Piezoelectric Acoustic Transducers Array based d33 Mode Polarization

2018 ◽  
Vol 10 (1) ◽  
pp. 59
Author(s):  
K.A. Ahmad ◽  
A. Abd Manaf ◽  
Z. Hussain Hussain ◽  
Z. Janin
Keyword(s):  
Image Resolution ◽  
Single Element ◽  
Sensing Element ◽  
Underwater Acoustic ◽  
Acoustic Transducers ◽  
Acoustic Transducer ◽  
Low Sensitivity ◽  
Pulse Echo ◽  
Is Design ◽  
Pulse Echo Method

Piezoelectric Acoustic Transducer (PAT) is a transducers used in many application such as medical diagnostic, medical ultrasonic imaging and underwater acoustic applications. Latest research, PAT were investigated in marine application and underwater acoustic imaging. Conventional PAT is design based on sensing element, Piezoelectric Material, matching layer and backing layer. But the conventional method still has problem with issues of narrow bandwidth, directivity and low sensitivity. This problem is occurred when the transducer need to increase the image resolution. The size of single element will become smaller to meet the requirement of high resolution. PZT-5H have high piezoelectric constant (d31) and low dielectric loss. It is chosen as sensing element in this design of PAT because it will increase the sensitivity of transducers. The PAT is design based on d33 mode polarization to improve the receiving sensitivity. The fabrication process are included wet etching on Printed Circuit Board (PCB), spin coated Polydimethylsiloxane (PDMS), and baked transducer on hot plate. PAT is characterized using Pulse-Echo method. Pulse-Echo method will determine the sensitivity, directivity and operating bandwidth of acoustic transducers in underwater applications. Open circuit receiving voltage (OCRV) is voltage response to determine the sensitivity of acoustic transducer. The commercial projector and hydrophone will calibrate to obtain the reliability of result. In cross talk test, at some particular frequency, Pin 2 and Pin 3 have low sensitivity value. It is because Pin 2 and Pin 3 received low acoustic wave pressure. The PAT array based d33 mode polarization shows it has more receiving sensitive compared to commercial acoustic transducers. The design transducer has sensitivity at -56 dB re 1V/µPa at resonance frequency, 100kHz and fractional bandwidth at 30%.

A method for the determination of the complex permittivity by detuned ring resonators for bulk materials up to 110 GHz

2015 ◽  
Vol 7 (3-4) ◽  
pp. 251-260 ◽  
Author(s):  
Armin Talai ◽  
Frank Steinhäußer ◽  
Achim Bittner ◽  
Ulrich Schmid ◽  
Robert Weigel ◽  
...  
Keyword(s):  
Effective Permittivity ◽  
Accurate Determination ◽  
Ring Resonators ◽  
Dielectric Losses ◽  
Bulk Materials ◽  
Resonance Frequencies ◽  
Measurement Results ◽  
Microwave Materials

An accurate characterization of microwave materials is essential for reliable high-frequency circuit design. This paper presents a measurement setup, which enables a quick and accurate determination of the relative permittivity of dielectric bulk materials up to 110 GHz. A ring-resonator is manufactured on a well-characterized substrate, serving as reference resonator. The material under test (MUT) is placed on top of the ring, which increases the effective permittivity and therefore introduces a shift of the resonance frequency of the resonator. In case of moderate to large dielectric losses of the MUTs, the quality factor of the resonator decreases perceptibly, which provides conclusions about the dielectric losses. Electromagnetic field simulations with different heights and relative permittivities of the MUTs provide a look-up table for the measured resonance frequencies. The functionality of the proposed measurement setup is validated by measurement results of different MUTs.

A quantitative approach to inner shell losses

1978 ◽  
Vol 36 (1) ◽  
pp. 526-527 ◽  
Author(s):  
R.D. Leapman ◽  
P. Rez ◽  
D.F. Mayers
Keyword(s):  
Energy Transfer ◽  
Cross Section ◽  
Cross Sections ◽  
Accurate Determination ◽  
Background Intensity ◽  
Core Excitation ◽  
Quantitative Basis ◽  
Cross Section Differential ◽  
Bound Electrons

Microanalysis by EELS has been developing rapidly and though the general form of the spectrum is now understood there is a need to put the technique on a more quantitative basis (1,2). Certain aspects important for microanalysis include: (i) accurate determination of the partial cross sections, σx(α,ΔE) for core excitation when scattering lies inside collection angle a and energy range ΔE above the edge, (ii) behavior of the background intensity due to excitation of less strongly bound electrons, necessary for extrapolation beneath the signal of interest, (iii) departures from the simple hydrogenic K-edge seen in L and M losses, effecting σx and complicating microanalysis. Such problems might be approached empirically but here we describe how computation can elucidate the spectrum shape.The inelastic cross section differential with respect to energy transfer E and momentum transfer q for electrons of energy E0 and velocity v can be written as

Fast calibration of CBED patterns for quantitative analysis

1993 ◽  
Vol 51 ◽  
pp. 674-675
Author(s):  
M.A. Gribelyuk ◽  
M. Rühle
Keyword(s):  
Reciprocal Lattice ◽  
Accurate Determination ◽  
Incident Beam ◽  
Crystal Thickness ◽  
Structure Model ◽  
Beam Direction ◽  
Transmitted Beam ◽  
Reciprocal Vector ◽  
On Line

A new method is suggested for the accurate determination of the incident beam direction K, crystal thickness t and the coordinates of the basic reciprocal lattice vectors V1 and V2 (Fig. 1) of the ZOLZ plans in pixels of the digitized 2-D CBED pattern. For a given structure model and some estimated values Vest and Kest of some point O in the CBED pattern a set of line scans AkBk is chosen so that all the scans are located within CBED disks.The points on line scans AkBk are conjugate to those on A0B0 since they are shifted by the reciprocal vector gk with respect to each other. As many conjugate scans are considered as CBED disks fall into the energy filtered region of the experimental pattern. Electron intensities of the transmitted beam I0 and diffracted beams Igk for all points on conjugate scans are found as a function of crystal thickness t on the basis of the full dynamical calculation.

Computer-Assisted High-Re Solution TEM

1990 ◽  
Vol 48 (1) ◽  
pp. 162-163
Author(s):  
F.A. Ponce ◽  
H. Hikashi
Keyword(s):  
Signal To Noise Ratio ◽  
Accurate Determination ◽  
Computer Software ◽  
Video Camera ◽  
Image Contrast ◽  
Objective Lens ◽  
Computer Assisted ◽  
Optical Parameters ◽  
Astigmatism Correction

The determination of the atomic positions from HRTEM micrographs is only possible if the optical parameters are known to a certain accuracy, and reliable through-focus series are available to match the experimental images with calculated images of possible atomic models. The main limitation in interpreting images at the atomic level is the knowledge of the optical parameters such as beam alignment, astigmatism correction and defocus value. Under ordinary conditions, the uncertainty in these values is sufficiently large to prevent the accurate determination of the atomic positions. Therefore, in order to achieve the resolution power of the microscope (under 0.2nm) it is necessary to take extraordinary measures. The use of on line computers has been proposed [e.g.: 2-5] and used with certain amount of success.We have built a system that can perform operations in the range of one frame stored and analyzed per second. A schematic diagram of the system is shown in figure 1. A JEOL 4000EX microscope equipped with an external computer interface is directly linked to a SUN-3 computer. All electrical parameters in the microscope can be changed via this interface by the use of a set of commands. The image is received from a video camera. A commercial image processor improves the signal-to-noise ratio by recursively averaging with a time constant, usually set at 0.25 sec. The computer software is based on a multi-window system and is entirely mouse-driven. All operations can be performed by clicking the mouse on the appropiate windows and buttons. This capability leads to extreme friendliness, ease of operation, and high operator speeds. Image analysis can be done in various ways. Here, we have measured the image contrast and used it to optimize certain parameters. The system is designed to have instant access to: (a) x- and y- alignment coils, (b) x- and y- astigmatism correction coils, and (c) objective lens current. The algorithm is shown in figure 2. Figure 3 shows an example taken from a thin CdTe crystal. The image contrast is displayed for changing objective lens current (defocus value). The display is calibrated in angstroms. Images are stored on the disk and are accessible by clicking the data points in the graph. Some of the frame-store images are displayed in Fig. 4.

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