Acoustic power distribution techniques for wireless sensor networks

Recent advancements in wireless power transfer technologies can solve several residual problems concerning the maintenance of wireless sensor networks. Among these, air-based acoustic systems are still less exploited, with considerable potential for powering sensor nodes. This thesis aims to understand the significant parameters for acoustic power transfer in air, comprehend the losses, and quantify the limitations in terms of distance, alignment, frequency, and power transfer efficiency. This research outlines the basic concepts and equations overlooking sound wave propagation, system losses, and safety regulations to understand the prospects and limitations of acoustic power transfer. First, a theoretical model was established to define the diffraction and attenuation losses in the system. Different off-the-shelf transducers were experimentally investigated, showing that the FUS-40E transducer is most appropriate for this work. Subsequently, different load-matching techniques are analysed to identify the optimum method to deliver power. The analytical results were experimentally validated, and complex impedance matching increased the bandwidth from 1.5 to 4 and the power transfer efficiency from 0.02% to 0.43%. Subsequently, a detailed 3D profiling of the acoustic system in the far-field region was provided, analysing the receiver sensitivity to disturbances in separation distance, receiver orientation and alignment. The measured effects of misalignment between the transducers are provided as a design graph, correlating the output power as a function of separation distance, offset, loading methods and operating frequency. Finally, a two-stage wireless power network is designed, where energy packets are inductively delivered to a cluster of nodes by a recharge vehicle and later acoustically distributed to devices within the cluster. A novel dynamic recharge scheduling algorithm that combines weighted genetic clustering with nearest neighbour search is developed to jointly minimise vehicle travel distance and power transfer losses. The efficacy and performance of the algorithm are evaluated in simulation using experimentally derived traces that presented 90% throughput for large, dense networks.Open Acces

Aeronautical engineering: A continuing bibliography with indexes (supplement 267)

This bibliography lists 661 reports, articles, and other documents introduced into the NASA scientific and technical information system in June, 1991. Subject coverage includes design, construction and testing of aircraft and aircraft engines; aircraft components, equipment and systems; ground support systems; theoretical and applied aspects of aerodynamics and general fluid dynamics; electrical engineering; aircraft control; remote sensing; computer sciences; nuclear physics; and social sciences

1995 BRAC Commission

ARD Detachment, Naval Surface Warfare Center Carderock Division, Naval Surface Warfare Center Carderock Division Detachment Annapolis, Naval Surface Warfare Center Carderock Philadelphia Detachment. Data Call 64. Box 181, L-113

New Indicators for the Assessment and Prevention of Noise Nuisance

This Special Issue was launched to promote a subject that is deserving of more attention: the study of new metrics, indicators or evaluation methods for noise exposure, and the relationship of noise with annoyance or other health effects, thus not relying only on an average noise exposure measure. This Special Issue on the theme of the New Indicators for the Assessment and Prevention of Noise Nuisance has attracted the interest of authors from all over the world, with the publication of two reviews and two communications, as well as original research papers. Progress has been made in the investigated topic; however, it is still necessary to increase the awareness of the population, both in geographical terms and for workers in specific sectors, such as the marine industry. It emerged that it is essential to carry out future studies that distinguish better between different sound sources with respect to their sound quality in terms of frequency, time pattern (fluctuation, emergence), and psychoacoustic indices, because a differential human reaction to sound sources is increasingly evident. More longitudinal studies are required. However, cross-sectional studies employing a more detailed soundscape description (including background) by competing sound indices are also useful to further the required knowledge to understand the human response in terms of the broad spectrum of potential adverse effects on health and quality of life

University of Nebraska at Omaha 2017-2018 Course Catalog

The University of Nebraska Omaha (UNO) is a premier metropolitan university that combines the resources of a doctoral research institution with a thriving community in the heart of Omaha. With a global reach and vision, UNO is large enough to provide opportunities students seek, yet personal enough to include the mentorship they need to achieve academic excellence, creativity, and engaged learningat competitive tuition rates. UNO is committed to and engaged with the city surrounding it, allowing students unique hands-on opportunities, internships, service learning,applied research, and other collaborative activities that enhance time in the classroom. This is the ”O” we want you to know – forward thinking, student centered,and devoted to the city we call home. #KnowThe

University of Nebraska at Omaha 2018-2019 Course Catalog

Located in one of America’s best cities to live, work and learn, the University of Nebraska at Omaha (UNO) is Nebraska’s premier metropolitan university. With more than 15,000 students enrolled in 200-plus programs of study, UNO is recognized nationally for its online education, graduate education, military friendliness, and community engagement efforts.Founded in 1908, UNO has served learners of all backgrounds for more than 100 years and is dedicated to another century of excellence both in the classroom and in the community

University of Nebraska at Omaha 2019-2020 Course Catalog

Located in one of America’s best cities to live, work and learn, the University of Nebraska at Omaha (UNO) is Nebraska’s premier metropolitan university. With more than 15,000 students enrolled in 200-plus programs of study, UNO is recognized nationally for its online education, graduate education, military friendliness, and community engagement efforts. Founded in 1908, UNO has served learners of all backgrounds for more than 100 years and is dedicated to another century of excellence both in the classroom and in the communit