The major task of imaging systems used in non-destructive testing is detection of defects (flaws, holes) echoes and evaluation or their dimensions and position. Images generated by direct imaging are poor quality due to diffraction, coherent echoes, limited capabilities of system, white noise. So acoustic images and optic images are very different. Solving these problems, numerical methods are used for signal processing and analysis. An application for ultrasonic signal processing of wavelet transformations was investigated in the work. The investigation was signals distortion type and level when wavelets transformation may give effective results. The investigation was performed using modeling and signal processing of the experimental signals.

This project has investigated and described a new ultrasonic, piezoelectrical, cylindrical "shaking beam" type actuator, meant for production of a new 3 degree of freedom operation piezomotor. Frequentive cheracteristics and ecliptical trajectory of contact points were also set in this project. Model of ultrasonic oscilatory system was developed and analysed by the programme ANSYS 6.1 using method of finite elements.

We have realized this work in cooperation with the Laboratory of Ophtalmology, Institute for Biomedical Research, Kaunas Medical University and Department of Anatomy and Physiology, Lithuanian Veterinary Academy. Using A-mode ultrasonography, we investigated structural parameters of the rabbit eye. The intraocular dimensions measured were as follows: distance between the anterior cornea to the anterior lens (CA), Thickness of the lens, distance between the surface of the retina (V), distance from the anterior cornea to the retina, which represents the total axial thickness. We have designed the original investigation methods and ultrasonic equipment with ultrasonic tranducer (f=12 Mhz). Using the acoustodiagnostic system, we were carrying out precise biometry of eye tissues. Ultrasonic investigations were done on 10 eyes of rabbit’s age 12 month. Comparative investigation between rabbits and pigs eye structural elements was done. The percentage relation between total axial length and other ocular dimensions rabbits and pigs eyes was estimated.

Mechanical waves provide information about the stiffness and the condition of a medium; thus, changes in medium conditions can be inferred from changes in wave velocity and attenuation. Non-destructive testing (NDT) methods based on ultrasonic waves are often more economical, practical and faster than destructive testing. Multichannel analysis of surface waves (MASW) is a well-established surface wave method used for determination of the shear-wave profile of layered medium. The MASW test configuration is also applicable to assess the condition of concrete elements using appropriate frequency range. Both attenuation and dispersion of ultrasonic waves can be evaluated by this technique. In ultrasonic testing, the characterization of a medium requires the precise measurement of its response to ultrasonic pulses to infer the presence of defects and boundary conditions. However, any ultrasonic transducer attached to a surface affects the measured response; especially at high frequencies. On the other hand, ultrasonic transducers available for engineering application are mostly used to measure wave velocities (travel time method). Therefore, these transducers do not have a flat response in the required frequency range. Moreover, in the case of full-waveform methods, the recorded signals should be normalized with respect to the transfer functions of the transducers to obtain the real response of the tested specimen. The main objective of this research is to establish a comprehensive methodology based on surface wave characteristics (velocity, attenuation and dispersion) for condition assessment of cemented materials with irregular defects. To achieve the major objective, the MASW test configuration is implemented in the ultrasonic frequency range. The measured signals are subjected to various signal processing techniques to extract accurate information. In addition, a calibration procedure is conducted to determine the frequency response functions (FRF) of the piezoelectric accelerometers outside their nominal frequency range. This calibration is performed using a high-frequency laser vibrometer. This research includes three main studies. The first study introduces the calibration approach to measure the FRFs of the accelerometers outside of their flat frequency range. The calibrated accelerometers are then used to perform MASW tests on a cemented-sand medium. The original signals and the corrected ones by eliminating the effect of the FRFs are used to determine material damping of the medium. Although, the damping ratios obtained from different accelerometers are not same, the values from the corrected signals are found closer to the characteristic damping value compared to those from the uncorrected signals. The second study investigates the sensitivity of Rayleigh wave velocity, attenuation coefficient, material damping and dispersion in phase velocity to evaluate the sensitivity of these characteristics to the damage quantity in a medium. The soft cemented-sand medium is preferred as the test specimen so that well-defined shaped defects could be created in the medium. MASW test configuration is implemented on the medium for different cases of defect depth. The recorded signals are processed using different signal processing techniques including Fourier and wavelet transforms and empirical mode decomposition to determine the surface wave characteristics accurately. A new index, ‘dispersion index’, is introduced which quantifies the defect based on the dispersive behaviour. All surface wave characteristics are found capable of reflecting the damage quantity of the test medium at different sensitivity levels. In the final study, the condition assessment of six lab-scale concrete beams with different void percent is performed. The beam specimens involving Styrofoam pellets with different ratios are tested under ultrasonic and mechanical equipment. The assessment produce established in the second study with well-defined defects is pursed for the beams with irregular defects. Among the characteristics, attenuation, P and R-wave velocities and dispersion index are found as the promising characteristics for quantifying the defect volume.

An automated prototype variable rate (VR) sprayer was developed for control of eight individual nozzles on a 6.1 m sprayer boom for spot-application (SA) of agrochemicals in wild blueberry fields. The VR control system consisted of eight ultrasonic sensors and four cameras mounted on a separate boom in front of the ATV, flow controller, VR controller, ruggedized computer, flow valve and solenoid valves. Custom software was capable of processing the images to detect weeds or plants in real-time and automatically send a signal to the VR controller for SA at the correct target. The performance of VR sprayer for SA on weeds (herbicide) and foliage (fungicide) was evaluated in commercial wild blueberry fields. Based on the results of this study, the VR sprayer was reliable, efficient and accurate enough for SA of agrochemicals. The average volume of chemical saved with SA was 70 % herbicide and 30 % fungicide.

Magistratūros baigiamajame darbe buvo analizuojamas jūrinio transportinio laivo korpuso korozinis dilimas ir jo priežastys, pateikiami defektacijos metodai, vertinami eksperimentinių matavimų metu gauti rezultatai. Baigiamasis darbas susideda iš teorinės, eksperimentinės ir praktinės dalies. Teorinėje dalyje apžvelgtos laivo korpuso nusidėvėjimo problemos, apžvelgti klasifikacinių bendrovių reikalavimai laivo korpuso būklei, išnagrinėtos laivo korpuso remonto technologijos. Eksperimentinėje dalyje pateiktos balkerio ,,LEDI CHRIS“ korpuso konstrukcijų liekamojo storio matavimo ultragarsiniu stormačiu rezultatai, palyginti matavimų duomenys, gauti laivo korpuso defektacijos tyrimo metu 2002, 2007 ir 2012 m., nustatytos labiausiai korozinio proceso paveiktos laivo konstrukcijos. Praktinėje baigiamojo darbo dalyje buvo atlikti skaičiavimai, siekiant nustatyti laivo korpuso lakštu stipruma po korozijos poveikio ir apskaičiuota tikimybes analize. / The master‘s thesis analyses the causes of the corrosive wear in marine transport ships. It is further followed by the examples of the flaw detection methods and the assessment of the results obtained through experimental measurements. The thesis has theoretical, experimental and practical parts to it. The theoretical part entails the review of the issues related to the depreciation of the ship‘s hull. Moreover, the theory includes the overview of the requirements imposed by the classification society in regards to the condition of the ship‘s hull. The thesis also brings forth the examination of the repair technology that is being used in connection to such issues. The experimental section of the thesis entails the residual thickness measurements of the hull structures obtained through the ultrasonic calipers that were applied on the bunker „LEDI CHRIS“. The comparison of the measurements‘results is also provided, based mainly on the data taken from the flaw detection test that was administered in the years 2002, 2007 and 2012. Additionally, the thesis identifies the structures of the ship that were impacted the most by the process of the corrosion. Last but not least, the practical part of the thesis presents calculations that were conducted in order to determine the durability of the ship‘s hull plating that was affected by the corrosion. The thesis concludes with the probability analysis of the corrosion causes.

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Thesis (M.Tech.: Chiropractic)-Dept.of Chiropractic, Durban Institute of Technology, 2003 / Medial Tibial Stress Syndrome Type II (MTSS), otherwise known as shin splints, accounts for approximately 13% of injuries in American runners. Van Mechelen (1992) reported that 37-57% of recreational runners experience an injury over the course of a year, from which 54-75% of all injuries are caused by overuse. The American Medical Association defines shin splints as “pain and discomfort in the leg from repetitive activity on hard surfaces, or due to forceful, excessive use of foot flexors. The diagnosis should be limited to musculoskeletal inflammations excluding stress fractures and ischemic disorders.” (Thacker et al., 2002) Treatment protocols vary from biomechanical interventions (orthotics), to non-steroidal anti-inflammatory drugs and modalities such as ultrasound all with varying degrees of success (Noakes, 2001). Apart from therapeutic interventions it is the overriding symptom of pain, which patients are left with (Noakes, 2001). A therapeutic intervention called periosteal pecking has received increased interest with regards to symptomatic treatment of shin splints. Periosteal pecking is a form of *dry needling in which the tip of the needle contacts the periosteum (Raso,1997). The aim of this study is to establish the effect of periosteal pecking in the clinical setting with and against that of an established intervention, namely therapeutic ultrasound.