2,844 research outputs found

    Robotic Ultrasound Imaging: State-of-the-Art and Future Perspectives

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    Ultrasound (US) is one of the most widely used modalities for clinical intervention and diagnosis due to the merits of providing non-invasive, radiation-free, and real-time images. However, free-hand US examinations are highly operator-dependent. Robotic US System (RUSS) aims at overcoming this shortcoming by offering reproducibility, while also aiming at improving dexterity, and intelligent anatomy and disease-aware imaging. In addition to enhancing diagnostic outcomes, RUSS also holds the potential to provide medical interventions for populations suffering from the shortage of experienced sonographers. In this paper, we categorize RUSS as teleoperated or autonomous. Regarding teleoperated RUSS, we summarize their technical developments, and clinical evaluations, respectively. This survey then focuses on the review of recent work on autonomous robotic US imaging. We demonstrate that machine learning and artificial intelligence present the key techniques, which enable intelligent patient and process-specific, motion and deformation-aware robotic image acquisition. We also show that the research on artificial intelligence for autonomous RUSS has directed the research community toward understanding and modeling expert sonographers' semantic reasoning and action. Here, we call this process, the recovery of the "language of sonography". This side result of research on autonomous robotic US acquisitions could be considered as valuable and essential as the progress made in the robotic US examination itself. This article will provide both engineers and clinicians with a comprehensive understanding of RUSS by surveying underlying techniques.Comment: Accepted by Medical Image Analysi

    Aerospace Medicine and Biology: A continuing bibliography with indexes, supplement 182, July 1978

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    This bibliography lists 165 reports, articles, and other documents introduced into the NASA scientific and technical information system in June 1978

    Experimental and finite element modelling of ultrasonic cutting of food

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    In recent years ultrasonic cutting has become an established technology in a variety of industries including the food processing industry to cut a variety of materials. An ultrasonic cutting system consists of a generator, transducer and either a single or multiple blade cutting devices tuned to a specific mode of vibration, commonly the longitudinal mode, between 20 and 100 kHz. High power ultrasonic cutting device design has traditionally relied on the cut requirements of the product, the use of empirical approaches where ultrasonic cutting system parameters such as cutting speed, frequency of vibration, mode of vibration, blade tip amplitude, gain and cutting orientation are determined from experimental and experience of the tool designers. Finite element (FE) models have also been used to predict the vibrational behaviour of the cutting tool. However, the performance of an ultrasonic device critically relies on the interaction of the cutting tool and material to be cut. Currently the interaction between the resonant blade and the material to be cut is neglected but the cutting mechanism at the interface is of significant importance and knowledge of this mechanism would be of considerable benefit to designers when developing ultrasonic cutting blade concepts and processing requirements. Simulations of the cutting process would also enable designers to conduct parametric studies quickly using computational methods instead of conducting lengthy, laborious experimental tests. The research reported in this thesis provides an insight into the requirements of the tool-material interaction to allow optimal cutting parameters to be estimated as an integral part of designing cutting blades for use in the food industry. A methodology is proposed for modelling the interaction between the resonant blade and the material to be cut using the finite element method, to gain an understanding of the cutting mechanism. The effect of ultrasonic cutting parameters, such as resonant frequency, mode of vibration, blade tip sharpness, cutting force, cutting speed, blade tip amplitude and are also investigated. Knowledge of the temperature distribution at the interface between the resonant blade and the substrate material would also be of benefit as currently experimental determination of the temperature at the interface is impractical using current measuring systems. Two thermo-mechanical FE models of ultrasonic cutting are developed which simulate the cutting tool and material interaction to allow cutting parameters to be derived numerically to enhance cutting blade design. The FE models incorporate experimentally derived mechanical and thermal properties of the common engineering thermoset Perspex and also of the following food materials; toffee, cheese, chocolate and jelly. The combined thermo-stress FE model allows the temperature at the cut interface to be determined under various loading conditions and provides a method for investigating the effects of blade design on temperature at the blade-material interface. Estimations of accurate mechanical and thermal properties of foodstuffs for inclusion in the FE models are determined experimentally using materials testing techniques such as tension and compression tests. Ultrasonic cutting blades are designed using finite element analysis and experimental investigations are performed on an ultrasonic cutting rig to validate the FE models. Two different generic 2D modelling approaches to simulate ultrasonic cutting are presented. One uses the debond method in ABAQUS standard and the alternative uses the element erosion method in ABAQUS explicit. Progression of the element erosion method into a 3D model is also presented with the intension of improving the accuracy of the modelling technique and to offer the flexibility to model complex geometries or cutting orientations. The models are presented and validated experimentally against a common engineering material, Perspex, and parametric studies are presented and discussed for the food materials; toffee, cheese, chocolate and jelly. For accurate modelling of any process, accurate material data is required and for common engineering materials such as Perspex accurate data is readily available in the literature. For food products however, the mechanical and thermal properties are not readily available and are often batch dependent. Methodologies for testing and determining the mechanical and thermal properties of two selected food materials, toffee and cheese, are also presented and the results from these experimental tests are incorporated in the finite element models to simulate the food materials during ultrasonic cutting. Models of ultrasonic cutting are for both single layer materials and also for multi layer material architectures

    Aerospace medicine and biology, a continuing bibliography with indexes. Supplement 236

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    This bibliography lists 207 reports, articles, and other documents introduced into the NASA scientific and technical information system in August 1982

    A comparison of processing techniques for producing prototype injection moulding inserts.

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    This project involves the investigation of processing techniques for producing low-cost moulding inserts used in the particulate injection moulding (PIM) process. Prototype moulds were made from both additive and subtractive processes as well as a combination of the two. The general motivation for this was to reduce the entry cost of users when considering PIM. PIM cavity inserts were first made by conventional machining from a polymer block using the pocket NC desktop mill. PIM cavity inserts were also made by fused filament deposition modelling using the Tiertime UP plus 3D printer. The injection moulding trials manifested in surface finish and part removal defects. The feedstock was a titanium metal blend which is brittle in comparison to commodity polymers. That in combination with the mesoscale features, small cross-sections and complex geometries were considered the main problems. For both processing methods, fixes were identified and made to test the theory. These consisted of a blended approach that saw a combination of both the additive and subtractive processes being used. The parts produced from the three processing methods are investigated and their respective merits and issues are discussed

    Reducing risk in pre-production investigations through undergraduate engineering projects.

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    This poster is the culmination of final year Bachelor of Engineering Technology (B.Eng.Tech) student projects in 2017 and 2018. The B.Eng.Tech is a level seven qualification that aligns with the Sydney accord for a three-year engineering degree and hence is internationally benchmarked. The enabling mechanism of these projects is the industry connectivity that creates real-world projects and highlights the benefits of the investigation of process at the technologist level. The methodologies we use are basic and transparent, with enough depth of technical knowledge to ensure the industry partners gain from the collaboration process. The process we use minimizes the disconnect between the student and the industry supervisor while maintaining the academic freedom of the student and the commercial sensitivities of the supervisor. The general motivation for this approach is the reduction of the entry cost of the industry to enable consideration of new technologies and thereby reducing risk to core business and shareholder profits. The poster presents several images and interpretive dialogue to explain the positive and negative aspects of the student process

    The Boston University Photonics Center annual report 2005-2006

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    This repository item contains an annual report that summarizes activities of the Boston University Photonics Center in the 2005-2006 academic year. The report provides quantitative and descriptive information regarding photonics programs in education, interdisciplinary research, business innovation, and technology development. The Boston University Photonics Center (BUPC) is an interdisciplinary hub for education, research, scholarship, innovation, and technology development associated with practical uses of light.This Annual Report is intended to serve as a synopsis of the Boston University Photonics Center’s wide-ranging activities for the period from July 2005 through June 2006, corresponding to the University’s fiscal year. It is my hope that the document is reflective of the Center’s core values in innovation, entrepreneurship, and education, and that it projects our shared vision, and our dedication to excellence in this exciting field. For further information, you may visit our new website at www.bu.edu/photonics. Though only recently appointed as Director, my involvement in Center activities dates back to the Center’s formation more than ten years ago. In the early years, I worked with a team of faculty and staff colleagues to design and construct the shared laboratories that now provide every Center member extraordinary capabilities for fabrication and testing of advanced photonic devices and systems. I helped launch the business incubator by forming a company around an idea that emerged from my research laboratory. While that company failed to realize its vision of transforming the compact disc industry, it did help us form a unique vision for our program of academically engaged business acceleration. I co-developed a course in optical microsystems for telecommunications that I taught to advanced undergraduates and graduate students in the new M.S. degree program in Photonics offered through the Electrical and Computer Engineering Department. And since the Center’s inception, I have contributed to its scholarly mission through my work in optical microsystem design and precision manufacturing at the Center’s core Precision Engineering Research Laboratory. Recently, I had the opportunity to lead the Provost’s Faculty Advisory Committee on Photonics, charged with broadening the Center’s mission to better integrate academic and educational programs with its more established programs for business incubation and prototype development. [TRUNCATED

    Human Machine Interfaces for Teleoperators and Virtual Environments

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    In Mar. 1990, a meeting organized around the general theme of teleoperation research into virtual environment display technology was conducted. This is a collection of conference-related fragments that will give a glimpse of the potential of the following fields and how they interplay: sensorimotor performance; human-machine interfaces; teleoperation; virtual environments; performance measurement and evaluation methods; and design principles and predictive models

    The 2019 surface acoustic waves roadmap

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    Today, surface acoustic waves (SAWs) and bulk acoustic waves are already two of the very few phononic technologies of industrial relevance and can been found in a myriad of devices employing these nanoscale earthquakes on a chip. Acoustic radio frequency filters, for instance, are integral parts of wireless devices. SAWs in particular find applications in life sciences and microfluidics for sensing and mixing of tiny amounts of liquids. In addition to this continuously growing number of applications, SAWs are ideally suited to probe and control elementary excitations in condensed matter at the limit of single quantum excitations. Even collective excitations, classical or quantum are nowadays coherently interfaced by SAWs. This wide, highly diverse, interdisciplinary and continuously expanding spectrum literally unites advanced sensing and manipulation applications. Remarkably, SAW technology is inherently multiscale and spans from single atomic or nanoscopic units up even to the millimeter scale. The aim of this Roadmap is to present a snapshot of the present state of surface acoustic wave science and technology in 2019 and provide an opinion on the challenges and opportunities that the future holds from a group of renown experts, covering the interdisciplinary key areas, ranging from fundamental quantum effects to practical applications of acoustic devices in life science
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