ABSTRACT The effects of ultrasonic irradiation at different frequencies, i.e. 0.25, 0.5, 1, and 5 MHz, on the biological reaction of the single cell creature have been investigated. When multi-cell creature is exposed to ultrasound, this reaction will lead the biological effect becomes complex. Therefore, in this dissertation, a single cell creature is chosen to study the biological effects induced by ultrasound exposure. The paramecium, which possesses many features typical of higher-order animal cells, was considered as an appropriate choice for this study. The ability shown by ultrasound in promoting and/or accelerating many reactions has been shown to be a useful field. The resonant frequency of paramecium by using the ultrasound irradiation is an important parameter in this research. All other parameters being kept constant, it has been ascertained that an appropriate frequency value of ultrasound can be selected, capable of driving a biological reaction to its suitable yield. The oscillation of the cells in response to the ultrasound radiation is simulated using Rayleigh-Plesset¡¦s bubble activation theory. The resonant frequency of the unicellular creature is then calculated. In the experiment, the resonant (0.5 and 1 MHz) and non-resonant (0.25 and 5 MHz) frequencies were employed. The theoretical resonant frequency of the paramecium vacuole is among 0.5013~1.2703 MHz. In this thesis, the experiment included two different series. The exposure intensity is the major subject of the first experimental series to study the bioeffect of ultrasound. The waveform was set to the tone pulse mode, pulsing 1:1. The exposure duration was continued and maintained 5 minutes. For a given frequency, exposures of the paramecium were made over a range of intensities spanning 0 to 1.7 mW/cm2. The second experimental series was focused on the exposure duration of the ultrasound. The transducers were operating in a pulsed mode with two duty cycles of 1:1 and 1:9. All insonated samples were exposed to ultrasound with a spatial peak temporal peak intensity (SPTP) of 0.127 mW/cm2. The total ¡§with signal¡¨ time was about 6 minutes in each trial. In addition, the control samples and the treated samples would be re-incubated up to the 96 hr. When the 1 MHz frequency of ultrasound was irradiated in the samples, there was about 24% inhibition rate and 30% enhancement rate in the first experimental series. The 0.5 MHz frequency of ultrasound, which approaches to the resonant frequency range, also appeared the inhibitive and beneficial effect. In the second experimental series, the relative growth number was about 32.4% higher than that of unexposed sample. The inhibition or enhancement growth conditions did not appear apparently during irradiation the non-resonant frequency of ultrasound. Moreover, experimental evidence suggests that the sustaining growth effect can be expected, when the irradiation time is divided into parts.

Thesis (M.S. in Electrical Engineering) Naval Postgraduate School, June 1997. / Thesis advisors, Richard W. Adler, Jovan E. Lebaric. Includes bibliographical references (p. 45). Also available online.

The study of acoustic resonance in fluid-filled piping systems with and without mean flow is important for the nuclear industry. For this industry, it is vital to understand the acoustic resonance in their systems; however, no comprehensive experimental benchmark data or accurate modeling tool exists for predicting such a phenomenon. The main goals of the current research are to create a new experimental data bank for the conditions not tested earlier using the configurations of straight lines and branches, and to evaluate the applicability of the linear wave solution using different damping methods and a computational fluid dynamic (CFD) code to simulate the acoustic resonance in fluid-filled piping systems. In this experimental study, data on resonant frequencies and resonant amplitudes are collected and analyzed for a frequency range of 20–500 Hz for straight and branched tubes by varying their wall thicknesses, materials, and branch configurations at different flow rates and outlet boundary conditions. To be closer to the nuclear industry medium, water is employed in our experiments, contrasting to the fact that most of the available experiments reported were with air at a much lower sonic velocity. I consider here, in particular, measurements at the end of closed branches, upstream, downstream, and at different locations of the main line, as well as the interactions of different sonic velocities along the main pipes. A small diameter is chosen for the branched experiments since the decrease in the width of the main line and the branches has a pronounced effect on the resonant amplitudes due to an increased interaction among the unsteady shear layers forming across the side branches. The experimental results show that there is a strong effect of turbulent flow, wall material, and wall thickness on resonant amplitudes at frequencies above ∼250 Hz. Numerical investigations are performed solving the one-dimensional (1D) linear wave equation with constant and frequency-dependent damping terms and a CFD code. Employing frequency-dependent damping methodologies shows improvement in terms of resonant amplitude prediction over constant volumetric drag method. Comparing the 1D and CFD results shows that the CFD solution yields better predictions. / February 2017

Multiple scattering effects from bubble clouds are investigated in this study. A high performance, general purpose numerical tool for multiple scattering calculations is developed. This numerical tool is applied in three computational scenarios in this study. The total scattering cross section of a bubble cloud is investigated. Numerical results indicate that the resonant frequency of the bubble cloud is much lower than that of a single bubble. The variation of resonant frequency of multiple scattering is also studied. It is found that the resonant frequency decreases as the number of bubbles increases, or as the void fraction of the bubble cloud decreases. Phase distributions of bubble oscillations in various multiple scattering scenarios are presented. It is found that, at resonance, the bubbles synchronize to the same phase, which is indicative of the lowest mode of collective oscillation. At wave localization, half of the bubbles oscillate at phase 0 while the other half oscillate at phase Pi. An intuitive interpretation of this behavior is given.

Fairy shrimp is an anostraca plankton which is raised for watching and scientific study. In recent year, due to the large requirement of fairy shrimp in the market, to increase the hatching rate of fairy shrimp is an important topic. It is found that when an Artemia Cysts hatched by light, the pigment absorption spectra in the Cysts match with the optical wavelength of the experimental incubators. Furthermore, the effect of ultrasound can stimulate the growth or activation of the fairy shrimp, when the ultrasonic parameters of frequency, intensity, exposure time and exposure period are properly controlled in the hatching experiments. This thesis is then focusing on the biological activities to increase the hatching rate of fairy shrimp by light and ultrasound exposure. This work investigates the light effect on the hatching experiment using different wavelength and intensity of LED light; in addition, Cysts is exposed to ultrasound by ultrasonic cleaner and transducer. The resonant frequency of the Cysts is obtained from Rayleig ¡VPlesset bubble activation formula. The radiation of the resonant and non-resonant regions during the hatching experiments are then set up by this resonant frequency for comparison. Finally, according to the experimental results, the correlations of hatching rate with light wavelength, light intensity, resonant frequency and ultrasound intensity are studied by Taguchi Method to understand the play role of the light and ultrasound. The research results show that the hatching rate is 25 % by lamp irradiation, and the maximum hatching rate is 42.5 % by blue light in the light experiment. In ultrasound experiment, the highest incubate percentage, 35 %, is obtained by ultrasound frequency 0.25 MHz and ultrasound intensity 39.2 mW/cm2. In the confirmed test, the blue light plus ultrasound frequency of 0.25 MHz plus ultrasound intensity of 30.9 mW/cm2 can let the incubate percentage up to 48.3%. This is the highest incubate percentage one can get from these experiments. Finally, the results of Taguchi analysis shows that the Confidence level of light affecting the hatching rate is 100%; thus, light source is the most critical factor to affect the hatching procedure. The results of this research can be referred by an endangered species or high economic value of species to increase the rate of hitching.

For evaluation and quality control of concrete structures, the impact resonant frequency method is widely accepted for monitoring structure in-service properties and detecting structural damage. Common defects in concrete include consolidation problems during casting and development of micro-cracks during stages of hydration. Monitoring the dynamic characteristics of concrete plays an essential role in detecting real-time and early stages of deterioration. Ample research is focused on detecting large defects, however not much information is available on detection of minor defects of composites like fiber reinforced concrete. Change of elastic behavior when Polypropylene fibers are added as reinforcement is investigated. Destructive tests on structures in-service are not always feasible thus leaving non-destructive condition assessment as the only option. Amongst the various non-destructive tests available, vibrational tests provide a practical method to predict the dynamic moduli of structures (dynamic modulus of elasticity, dynamic modulus of rigidity and dynamic Poisson’s ratio). The objective of this research is to assess the dynamic elastic properties of Polypropylene Fiber Reinforced Concrete (PFRC) in correlation with induced cracks and common consolidation defects using a lab developed non-destructive testing method that relies on impulse excitation and stress wave propagation to measure changes in the resonant frequency when polypropylene fibers are added to concrete. In the experimental program, two fiber sizes, macro and micro, with various volume contents have been used for casting PFRC cylinders and prisms. Fundamental resonant frequencies were measured for all cylinders and prisms in the transverse and longitudinal directions. All measured frequencies are directly related to the low-strain dynamic modulus of elasticity. In addition, PFRC prisms were used to investigate the relationship between the dynamic modulus of elasticity and modulus of rigidity. Several batches of similar mixtures are used to investigate different parameters that affect the resonant frequency of concrete such as the water to cement ratio, curing condition and age. Results indicated a decrease in the resonant frequency and elastic properties with an increase of the fiber content or length. Micro fibers showed higher dynamic elastic moduli when compared to macro fibers of the same mixture under saturated curing conditions. Post-cracked PFRC cylinders and flexural fractured prisms retained some of the resonant frequency with macro fibers exhibiting better elastic recovery when cracked. / Graduate

This thesis represents one phase of a joint effort of research on the properties of liquids and solids. This work is concerned primarily with the microwave properties of solids. In this investigation the properties exhibited by conductor and semiconductor materials when they are subjected to electromagnetic radiation of microwave frequency are studied. The method utilized in this experiment is the perturbation of a resonant cavity produced by introduction of a cylindrically shaped sample into it.

A two-dimensional isotropic metamaterials formed by crossed split-ring resonators (CSRRs) are studied in this paper. The effective characteristic parameters of this media are determined by quasi-static Lorentz theory. The induced current distributions of a single CSRR at the resonant frequency are presented. Moreover, the dependence of the resonant frequency on the dimensions of single CSRR and the spaces of the array are also discussed. / Singapore-MIT Alliance (SMA)

Recently, the evolutions of wireless communication systems are growing rapidly to satisfy the personal communication requirements. Compact, small size, low cost, and multi-function are the major developing trends among these modern wireless communication devices. The use of ceramic materials with high permittivity can effectively reduce the sizes of microwave devices. This thesis consists of two parts: the research of microwave dielectric materials and the implementation of microstrip ceramic antennas. In the first part of the dissertation, the systematic investigations of the microstructure and microwave dielectric properties in respect of BiNbO4-based ceramics and MCAS glass-added Al2O3-TiO2 ceramics have presented. By the addition of CuO, V2O5, or CuO-V2O5 mixture, the BiNbO4 ceramics can be densified at lower sintering temperatures less than 940¢J. The excellent microwave dielectric properties are obtained as 0.5 wt% CuO or V2O5 are added as sintering aids. The exceeded additive amount or sintering temperatures will result in the appearance of abnormal grain growth and the increase of grain boundary inclusions, which will decrease the microwave dielectric properties including the quality factor (Q) and the temperature coefficient of resonant frequency (£nf). The CuO-added BiNbO4 ceramics reveal a negative £nf value and V2O5-added BiNbO4 ceramics reveal a positive one. The £nf values can be reduced to near 0 ppm/¢J by controlling the weight ratio of CuO/V2O5. Another method to reduce the £nf values to near 0 ppm/¢J is the substitution of Sm for Bi. For the (Bi1-xSmx)NbO4 ceramics, the presence of the £]-form of (Bi1-xSmx)NbO4 ceramics will affect the grain growth, density, Q¡Ñf values and £nf values, but that has no apparent effect on £`r values. On the whole, a high permittivity, an acceptable quality factor, and the temperature stable BiNbO4-based ceramic can be obtained. As for (1-x)Al2O3-xTiO2 ceramics, the addition of MCAS glass can lower the sintering temperatures of (1-x)Al2O3-xTiO2 ceramics from 1500¢J to 1300¢J. And the £nf value can be adjusted to near zero by controlling the TiO2 content and sintering temperature. The appearance of Al2TiO5 phase, resulted from the consumption of TiO2, exhibits intense effect on the microwave dielectric properties of (1-x)Al2O3 -xTiO2 ceramics. The major contributions in this research would be the lower sintering temperatures and the near 0 ppm/¢J of £nf value. The 2wt%- MCAS-added (1-x)Al2O3-xTiO2 ceramics sintered at 1300¢J and x = 0.12 has a minimum £nf value of ¡V0.6 ppm/¢J. In the second part of the dissertation, the microstrip antennas with high permittivity BiNbO4 ceramics (£`r = 43) substrate are fabricated. The bandwidths obtained are narrow and insufficient for the WLAN application. The techniques of U-slots patch and stacked structure are used to enhance the bandwidth of the microstrip ceramic antennas by combining the two adjacent resonant modes. The results indicate that the impedance bandwidth can be enhanced from 2.3% to 5.3% by embedding double U-shaped slots in the rectangular patch, or to 4.5% by using stacked patches.

abstract: The utilization of power cables is increasing with the development of renewable energy and the maintenance replacement of old overhead power lines. Therefore, effective monitoring and accurate fault location for power cables are very important for the sake of a stable power supply. The recent technologies for power cable diagnosis and temperature monitoring system are described including their intrinsic limitations for cable health assessment. Power cable fault location methods are reviewed with two main categories: off-line and on-line data based methods. As a diagnostic and fault location approach, a new passive methodology is introduced. This methodology is based on analyzing the resonant frequencies of the transfer function between the input and output of the power cable system. The equivalent pi model is applied to the resonant frequency calculation for the selected underground power cable transmission system. The characteristics of the resonant frequencies are studied by analytical derivations and PSCAD simulations. It is found that the variation of load magnitudes and change of positive power factors (i.e., inductive loads) do not affect resonant frequencies significantly, but there is considerable movement of resonant frequencies under change of negative power factors (i.e., capacitive loads). Power cable fault conditions introduce new resonant frequencies in accordance with fault positions. Similar behaviors of the resonant frequencies are shown in a transformer (TR) connected power cable system with frequency shifts caused by the TR impedance. The resonant frequencies can be extracted by frequency analysis of power signals and the inherent noise in these signals plays a key role to measure the resonant frequencies. Window functions provide an effective tool for improving resonant frequency discernment. The frequency analysis is implemented on noise laden PSCAD simulation signals and it reveals identical resonant frequency characteristics with theoretical studies. Finally, the noise levels of real voltage and current signals, which are acquired from an operating power plant, are estimated and the resonant frequencies are extracted by applying window functions, and these results prove that the resonant frequency can be used as an assessment for the internal changes in power cable parameters such as defects and faults. / Dissertation/Thesis / Doctoral Dissertation Electrical Engineering 2015