No description available.

No description available.

Additive friction stir deposition (AFSD) is an innovative solid-state manufacturing process capable of producing parts with fine, equiaxed grains. However, due to the complexity of extensive plastic deformation and the viscoplastic behavior of metallic materials at elevated temperatures, the analysis of material flow and stress evolution during AFSD remains at a rudimentary stage. As a developing technology, gaining a deeper understanding of the underlying physical behaviors behind the processing is appreciable. This study comprises three objectives: investigating microstructure and stress-induced acoustic wave propagation behaviors, implementing non-contact in-situ monitoring in AFSD of aluminum alloy 6061 using a far-collimation acoustic metamaterial lens, and ex-situ analysis of parameter-dependent mechanics influences in AFSD of aluminum alloys 6061. To achieve this, a novel ultrasound in-situ monitoring method, along with ex-situ residual stress measurements, is facilitated by MD and FEA simulations and been experimentally verified. Real-time asymmetric property distribution and abnormal parameter-dependence acoustic wave phase change during the AFSD of aluminum alloy 6061 were identified through the in-situ monitoring and further investigated in detail through ex-situ inspection. A key parameter, effective viscosity, was introduced to the parameter windows selections, which can affect the thermo-fluidic mechanics during the process, thereby altering the physical aspects, mechanical properties, and microstructures.

The objective of this study was to develop a new method for co-crystal preparation which adhered to green chemistry principles, and provided advantages over conventional methods. A novel, solvent-free, high-power ultrasound (US) technique, for preparing co-crystals from binary systems, was chosen as the technology which could fulfil these aims. The application of this technology for solid state co-crystal preparation was explored for ibuprofen-nicotinamide (IBU-NIC), carbamazepine-nicotinamide (CBZ-NIC) and carbamazepine-saccharin (CBZ-SAC) co-crystals. The effect of different additives and processing parameters such as power level, temperature and sonication time on co-crystallisation was investigated. Characterisation was carried out using DSC, PXRD, FTIR, Raman and HPLC. In addition, an NIR prediction model was developed and combined with multivariate analysis (PLS) and chemometric pre-treatments. It was found to be a robust, reliable and rapid method for the determination of co-crystal purity for the IBU-NIC and CBZ-NIC pairs. Co-crystal quantification of US samples helped to optimise the US method. Finally, a model formulation of paracetamol containing 5% and 10% PEG 8000 was ultrasonicated at maximum power with different exposure times. A comparison of technological and physicochemical properties of the resulting tablets with those of the tablets obtained using the pressing method evidenced significant differences. This suggested that US energy dissipation (mechanical and thermal effects) was the main mechanism which caused the PAR form I tabletability to improve. It was found that the ultrasound–compacted tablets released the drug at a slower rate compared to pure PAR. This technique was shown to be useful for improving tabletability for low-compressible drugs without the need to use a conventional tabletting machine.

In our work we have studied the ultrasonic imaging systems and their use in ophthalmology, especially with the device Nidek 4000. We described ophthalmological examination methods. In addition, we are using the simulation program Field II. It simulated eye phantom and created his B-scan and biometry, where we compared the effects of different central frequency ultrasonic probes and different speeds of sound in the resulting values. We also created phantoms using agarose gel and materials of different properties. On phantoms, we studied the effect of the velocity of ultrasound in measurement results, effect of the concentration of the agarose gel to the velocity of sound. And we created phantoms simulating the human eye. Measurement protocol was created for use in teaching.

The thesis deals with physical principles of ultrasound with following specialization on ophtalmic ultrasound system Nidek Echoscan 4000 and its properties. And also it deals with description of investigative techniques in ophthalmology (A-mode, B-mode, biometry and pachymetry). Next, they was suggested procedures of measurement and that is spatial resolution (axial and lateral spatial resolution) and propagation speed of ultrasound depending on the temperature. Then these properties was tested on laboratory phantoms of eye – ETETECH LTD. and Multipurpose Ultrasound Phantom but on created phantoms of eye too, which will be made from agarose gel with build-in materail (fishing line, plastic film, plastic bag and rubber). At the end, measured values was processed in the generated program.

This master thesis deals with the measurement properties of ultrasound probes. Ultrasound probes and their parameters significantly affect the quality of the final image. Values of pa-rameters of the probes may change due to their use, because probes may be damaged and the final image may no longer be correct. For these reasons the measurements of parameters of probes are very important. In this master thesis there are described and implemented the possibility of measuring the spatial resolution, focal zone, the sensitivity of the probe and measuring the length of the dead zone. Two ultrasonic phantoms were used for measuring. In the practical part there was created the program called Mereni_parametru, which allows to determine the value of four parameters from captured images of the phantom. Further, there are listed and described measured values for five ultrasonic probes. Results for two of these probes are then compared with the parameters given by the manufacturers.

The critical role of language pronunciation in communicative competence is significant, especially for second language learners. Despite renewed awareness of the importance of articulation, it remains a challenge for instructors to handle the pronunciation needs of language learners. There are relatively scarce pedagogical tools for pronunciation teaching and learning, such as inefficient, traditional pronunciation instructions like listening and repeating. Recently, electronic visual feedback (EVF) systems (e.g., medical ultrasound imaging) have been exploited in new approaches in such a way that they could be effectively incorporated in a range of teaching and learning contexts. Evaluation of ultrasound-enhanced methods for pronunciation training, such as multimodal methods, has asserted that visualizing articulator’s system as biofeedback to language learners might improve the efficiency of articulation learning. Despite the recent successful usage of multimodal techniques for pronunciation training, manual works and human manipulation are inevitable in many stages of those systems. Furthermore, recognizing tongue shape in noisy and low-contrast ultrasound images is a challenging job, especially for non-expert users in real-time applications. On the other hand, our user study revealed that users could not perceive the placement of their tongue inside the mouth comfortably just by watching pre-recorded videos. Machine learning is a subset of Artificial Intelligence (AI), where machines can learn by experiencing and acquiring skills without human involvement. Inspired by the functionality of the human brain, deep artificial neural networks learn from large amounts of data to perform a task repeatedly. Deep learning-based methods in many computer vision tasks have emerged as the dominant paradigm in recent years. Deep learning methods are powerful in automatic learning of a new job, while unlike traditional image processing methods, they are capable of dealing with many challenges such as object occlusion, transformation variant, and background artifacts. In this dissertation, we implemented a guided language pronunciation training system, benefits from the strengths of deep learning techniques. Our modular system attempts to provide a fully automatic and real-time language pronunciation training tool using ultrasound-enhanced augmented reality. Qualitatively and quantitatively assessments indicate an exceptional performance for our system in terms of flexibility, generalization, robustness, and autonomy outperformed previous techniques. Using our ultrasound-enhanced system, a language learner can observe her/his tongue movements during real-time speech, superimposed on her/his face automatically.

No description available.

The objective of this study was to develop a new method for co-crystal preparation which adhered to green chemistry principles, and provided advantages over conventional methods. A novel, solvent-free, high-power ultrasound (US) technique, for preparing co-crystals from binary systems, was chosen as the technology which could fulfil these aims. The application of this technology for solid state co-crystal preparation was explored for ibuprofen-nicotinamide (IBU-NIC), carbamazepine-nicotinamide (CBZ-NIC) and carbamazepine-saccharin (CBZ-SAC) co-crystals. The effect of different additives and processing parameters such as power level, temperature and sonication time on co-crystallisation was investigated. Characterisation was carried out using DSC, PXRD, FTIR, Raman and HPLC. In addition, an NIR prediction model was developed and combined with multivariate analysis (PLS) and chemometric pre-treatments. It was found to be a robust, reliable and rapid method for the determination of co-crystal purity for the IBU-NIC and CBZ-NIC pairs. Co-crystal quantification of US samples helped to optimise the US method. Finally, a model formulation of paracetamol containing 5% and 10% PEG 8000 was ultrasonicated at maximum power with different exposure times. A comparison of technological and physicochemical properties of the resulting tablets with those of the tablets obtained using the pressing method evidenced significant differences. This suggested that US energy dissipation (mechanical and thermal effects) was the main mechanism which caused the PAR form I tabletability to improve. It was found that the ultrasound–compacted tablets released the drug at a slower rate compared to pure PAR. This technique was shown to be useful for improving tabletability for low-compressible drugs without the need to use a conventional tabletting machine.