Detection of the tagged or untagged photons in acousto-optic imaging of thick highly scattering media by photorefractive adaptive holography

We propose an original adaptive wavefront holographic setup based on the photorefractive effect (PR), to make real-time measurements of acousto-optic signals in thick scattering media, with a high flux collection at high rates for breast tumor detection. We describe here our present state of art and understanding on the problem of breast imaging with PR detection of the acousto-optic signal

An Injury-Mimicking Ultrasound Phantom as a Training Tool for Diagnosis of Internal Trauma

Ultrasound phantoms that mimic injury are training devices that can emulate pre- and post-injury conditions within specific regions of human anatomy. They have the potential to be useful tools for teaching medical personnel how to recognize trauma conditions based on ultrasound images. This is particularly important because the increased use of portable ultrasound systems allows earlier diagnosis of internal trauma at locations such as traffic accidents, earthquakes, battlefields and terrorist attacks. A physical injury mimicking ultrasound phantom of the peritoneal cavity was constructed that mimicked the ultrasonic appearance of internal bleeding. Bleeding was simulated by injecting 600 mL of fluid of varying densities into the bulk of the phantom and comparing the ultrasonic appearance to before bleeding was simulated. The physical phantom was used to investigate whether or not the density of the injected fluid had any influence on the increase of inter-organ fluid volumes. The physical phantom was imaged in 3D with a 4.5 MHz phased array transducer, and two fluid volumes were segmented using the segmentation software ITK-SNAP. The 3D image representation of the phantom showed a difference qualitatively and quantitatively between pre-injury and post-injury conditions. Qualitatively, the physical model was analyzed. These specific criteria were analyzed within each image: 1) the number of individual organs that are present, 2) the number of other organs that each individual organ touches, 3) the appearance of fluid between the organs and the scanning membrane and 4) the merging of two separate fluid pockets. Using a Wilcoxon Rank-Sum test, a statistically significant difference was shown to exist between pre-injury and post-injury ultrasound images with a 95% level of confidence. Quantitatively, a Chi-Squared test was used to show that the volume of fluid between adjacent organs, calculated by ITK-SNAP, had no dependence on the density of the injected fluid. Furthermore, using a one-tailed T-test, there was at least a 99.9% confidence that the inter-organ volume estimations for the pre-injury and post-injury configurations were statistically different. As a final means of evaluation, the experimental phantom was taken to Harvard Medical School in November 2006 and analyzed by ultrasonographers. The doctors were very excited about its potential uses and found other interesting characteristics that the phantom was not designed for. In addition to modeling the appearance of an injected fluid volume, visualization of fluid flowing into the phantom, modeling the appearance of air in the inter-peritoneal space and simulating a surgical tool or bandage being accidentally left inside the patient could be modeled as well. The injury mimicking phantom was also modeled numerically, using ADINA finite element software. Using the same external dimensions as the experimental model, the numerical model showed that for physiologically unrealistic, very high fluid injection densities, the displacement of the organs had no statistical dependence on the density of the injected fluid, using an acceptance criterion of: P-value \u3c 0.05. This was confirmed using an F-test of the average organ phantom tip displacement tabulated at several different times during simulation. The P-value obtained for analyzing the average tip displacement was 0.0506. However, a plot of the mass ratio, an expression of how the injected fluid has dispersed into the bulk of the phantom, showed that an unrealistically high fluid injection density had a different mass ratio profile than the other fluid injection densities that were simulated. This F-test revealed a strong indication, P-value = 0.0069, that the very high density caused a different fluid dispersion pattern. The numerical phantom offered a distinct advantage over the experimental model in that the dispersion of the injected fluid could be modeled numerically but not observed experimentally. Modeling the phantom numerically had some disadvantages. The numerical model had to have a large gap between adjacent organs. This had to occur because the contact algorithm within ADINA is incapable of modeling dynamic contact when fluid-structure interactions are modeled. This led to a volume fraction representation of the solid domain that was too low compared with the experimental model and what is found anatomically. For future iterations of the injury mimicking phantom, the numerical model will be used to help design the physical phantoms

The Physics of Rodent Ultrasonic Vocalizations

Although much work has been done on the physics of vocalizations caused by the vibrating motion of vocal folds, relatively little work has been done on the physics of ultrasonic vocalizations (USVs). There are two orders of mammals known to make these kind of vocalizations: cetaceans and rodents. Of these two the mechanism behind the rodent calls are better understood. Thus, this thesis investigates the physics of rodent USVs with the hope that findings will help elucidate the mechanisms behind cetacean USVs. Chapter 1 discusses the anatomical background of rodent vocal tracts, evolutionary pressures that shaped the development of USVs, physical modeling of vibrating vocal folds, and experimental work that discounts the possibility of vibrating vocal folds as the mechanism behind rodent USVs. Chapter 2 discusses acoustic and fluid dynamics background as well as a previously proposed physical model, known as the hole tone, for the rodent USV mechanism. Chapter 3 discusses an original data analysis of rodent USVs. This analysis exploits the presence of frequency jumps in the USVs. These frequency jumps are extracted. A machine learning model is then used to fit the frequency jumps to acoustic equations. The results of this analysis show that the hole tone model is incorrect. Chapter 4 discusses original modeling of the rodent vocal production mechanism, in which the rodent vocal tract is treated as a resonator driven by a jet of air emerging from the vocal folds. This representation of the rodent vocal tract is used to derive a set of time domain acoustic oscillator equations, which describe the transient acoustics of rodent USVs. It is found in chapter 4 that an additional driving mechanism is needed in the oscillator equations, or the acoustic oscillations will decay to a fixed point. Chapter 5 discusses several attempts at including this driving mechanism by considering the forcing that results from the formation of vortex rings in the rodent vocal tract. First, a linear frequency domain approach is attempted. However, it is found that this approach is incompatible with the time domain equations of chapter 4. Next, a nonlinear time domain approach is attempted. This approach is compatible with the time domain equations of chapter 4, and solves the decay problem that occurs without the additional driving force. Furthermore, the model is able to reproduce the 22 kHz alarm call made by rats. However, it is unable to produce the higher harmonics or the frequency jumps observed in rodent USVs. It is concluded that the model is successful in producing the fundamental frequency of the rodent vocal tract, but it seems to be neglecting a mechanism which can account for the higher harmonics and the frequency jumps

The potential of additive manufacturing in the smart factory industrial 4.0: A review

Additive manufacturing (AM) or three-dimensional (3D) printing has introduced a novel production method in design, manufacturing, and distribution to end-users. This technology has provided great freedom in design for creating complex components, highly customizable products, and efficient waste minimization. The last industrial revolution, namely industry 4.0, employs the integration of smart manufacturing systems and developed information technologies. Accordingly, AM plays a principal role in industry 4.0 thanks to numerous benefits, such as time and material saving, rapid prototyping, high efficiency, and decentralized production methods. This review paper is to organize a comprehensive study on AM technology and present the latest achievements and industrial applications. Besides that, this paper investigates the sustainability dimensions of the AM process and the added values in economic, social, and environment sections. Finally, the paper concludes by pointing out the future trend of AM in technology, applications, and materials aspects that have the potential to come up with new ideas for the future of AM explorations

Cardiovascular instrumentation for spaceflight

The observation mechanisms dealing with pressure, flow, morphology, temperature, etc. are discussed. The approach taken in the performance of this study was to (1) review ground and space-flight data on cardiovascular function, including earlier related ground-based and space-flight animal studies, Mercury, Gemini, Apollo, Skylab, and recent bed-rest studies, (2) review cardiovascular measurement parameters required to assess individual performance and physiological alternations during space flight, (3) perform an instrumentation survey including a literature search as well as personal contact with the applicable investigators, (4) assess instrumentation applicability with respect to the established criteria, and (5) recommend future research and development activity. It is concluded that, for the most part, the required instrumentation technology is available but that mission-peculiar criteria will require modifications to adapt the applicable instrumentation to a space-flight configuration