Hursthelms0719

The use of an array of transducers to excite guided Lamb waves, within a plate or any complex structure, usually leads to a variation in the energy on the propagation direction. In this study, an optimization model is proposed to design an array of transducers to provide uniform energy distribution in a domain of an arbitrary shape. The model is based on finding the optimal placements of the transducers and the optimal time delay for excitation by using a genetic algorithm. The efficiency of the model was tested on an elliptically shaped domain, then on an arbitrarily shaped domain. Both cases showed promising results using various configurations/patterns of transducers. The method was experimentally validated on an aluminium alloy plate for two patterns of transducers including six and eight piezoelectric elements. Aluminum honeycomb has been widely used in many industrial fields, especially the aeronautics and aerospace industries, owing to its high strength and stiffness to weight ratio. Machining of aluminum honeycomb is usually associated with deformations and burrs. Ultrasonic cutting has been introduced as a promising method to overcome these constraints. In order to conduct in-depth research on the ultrasonic cutting for aluminum honeycomb by disc cutter, a 3D finite element model is carried out and verification tests are performed. Comparison result of simulated and experimental cutting forces indicates that the developed model agrees well with the experiment. Based on the developed model, cutting forces and contact relationship between cutter and honeycomb during the cutting process are studied. The reason for the periodic increase in cutting force is analyzed, subsequently. Moreover, the stress distribution in the cutting zone and honeycomb morphologies under different cutting conditions are compared and analyzed. Results show that the hexagonal structure of aluminum honeycomb can be protected and machining quality can be improved by using ultrasonic vibration. Therefore, high quality and efficient machining for aluminum honeycomb can be achieved. Speed of Sound (SoS) maps from ultrasound tomography (UST) provide valuable quantitative information for soft tissue characterization and identification of lesions, making this technique interesting for breast cancer detection. However, due to the complexity of the processes that characterize the interaction of ultrasonic waves with matter, classic and fast tomographic algorithms such as back-projection are not suitable. Consequently, the image reconstruction process in UST is generally slow compared to other more conventional medical tomography modalities. With the aim of facilitating the translation of this technique into real clinical practice, several reconstruction algorithms are being proposed to make image reconstruction in UST to be a fast and accurate process. The geometrical acoustic approximation is often used to reconstruct SoS with less computational burden in comparison with full-wave inversion methods. In this work, we propose a simple formulation to perform on-the-flight reconstruction for UST using geometrical acoustics with refraction correction based on quadratic Bézier polynomials. Here we demonstrate that the trajectories created with these polynomials are an accurate approximation to reproduce the refracted acoustic paths connecting the emitter and receiver transducers. The method is faster than typical acquisition times in UST. Thus, it can be considered a step towards real-time reconstructions, which may contribute to its future clinical translation. The opioid overdose epidemic kills about 130 people a day in the United States and it is estimated that there are about 2.1 million people who suffer from an opioid use disorder (OUD). Academic neuroscientists, psychiatrists and the National Institute of Drug Abuse have spent the last forty-years establishing the foundation of addiction as a brain disorder. It is now clear that extended opioid use causes multiple important and at times, irreversible changes to the brain, especially to its dopamine and opioid systems. With our recognized criteria for diagnosis and the accepted multifaceted treatment approach of both professional psychotherapy and medications that assist treatments, treatment failures should be limited. Unfortunately, this is not the case. Slips, relapses, overdose and multiple failures are all too common. Similar to treatment resistant depression there is a subpopulation who do not respond to standard OUD treatments. However, the field has suggested that if a treatment does not work, it is either the patients fault, they have not hit bottom or simply we need to try the same treatment again. There is a rational to consider this a new category of OUD, treatment resistant opioid use disorder (TROUD). This paper explores past treatment attempts data from OUD patients entering traditional outpatient treatment and makes recommendations how TROUD can be defined. It challenges the addiction research and treatment providers to change its focus from individuals being resistant to the unique conditions associated with this brain disorder as being resistant to treatment as usual. Zebrafish (Danio rerio) early life-stages are increasingly gaining attention as an alternative model in both human and environmental toxicology. Whereas there is amble knowledge about the transcription of various cytochrome P450 isoforms, the level of information about functional implications is still limited. This study investigated the development of CYP2-dependent 7-methoxycoumarin-O-demethylase (MCOD) activity throughout the early zebrafish development from 5 to 118 h post-fertilization (hpf) via confocal laser scanning microscopy. Results demonstrate that zebrafish embryos exhibit constitutive MCOD activity from as early as 5.5 hpf. Characteristic spatiotemporal patterns were documented with MCOD activities localized in several tissues and organs, namely the cardiovascular system, the brain, the digestive system, and the urinary tract. The study thereby contributes to a better understanding of the development and functional role of CYP enzymes in zebrafish early life-stages. 3-Methyladenine ic50