Akustisk teknologi og lydteknik

Wild Track is an exploration of birdsong and the ways in which that sound was conveyed, described and responded to through text, prior to the advent of recording and broadcast technologies in the late 19th and early 20th centuries. Street links sound aesthetics, radio, natural history, and literature to explore how the brain and imagination translate sonic codes as well as the nature of the silent sound we "hear" when we read a text. This creates an awareness of sound through the tuned attention of the senses, learning from sound texts of the natural world that sought - and seek - to convey the intensity of the sonic moment and fleeting experience. To absorb these lessons is to enable a more highly interactive relationship with sound and listening, and to interpret the subtleties of audio as a means of expression and translation of the living world.

This book provides the material for an introductory course in engineering acoustics for students with basic knowledge in mathematics. It is based on extensive teaching experience at the university level. Under the guidance of an academic teacher it is su?cient as the sole te- book for the subject. Each chapter deals with a well de?ned topic and r- resents the material for a two-hour lecture. The chapters alternate between more theoretical and more application-oriented concepts. For the purpose of self-study, the reader is advised to use this text in parallel with further introductory material. Some suggestions to this end are given in Appendix 15. 3. The authors thank Dorea Ruggles for providing substantial stylistic re?- ments. Further thanks go to various colleagues and graduate students who most willingly helped with corrections and proof reading. Nevertheless, the authors assume full responsibility for all contents. Bochum and Troy, Jens Blauert February 2008 Ning Xiang Contents 1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1. 1 De?nition of Three Basic Terms . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1. 2 Specialized Areas within Acoustics . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. 3 About the History of Acoustics . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 1. 4 Relevant Quantities in Acoustics . . . . . . . . . . . . . . . . . . . . . . . . . . 5 1. 5 Some Numerical Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 1. 6 Levels and Logarithmic Frequency Intervals . . . . . . . . . . . . . . . . . 8 1. 7 Double-Logarithmic Plots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 2 Mechanic and Acoustic Oscillations . . . . . . . . . . . . . . . . . . . . . . . . 13 2. 1 Basic Elements of Linear, Oscillating, Mechanic Systems . . . . . 14 2. 2 Parallel Mechanic Oscillators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 2. 3 Free Oscillations of Parallel Mechanic Oscillators . . . . . . . . . . . . 17 2. 4 Forced Oscillation of Parallel Mechanic Oscillators . . . . . . . . . . .

This book delivers a comprehensive and up-to-date treatment of practical applications of metamaterials, structured media, and conventional porous materials. With increasing levels of urbanization, a growing demand for motorized transport, and inefficient urban planning, environmental noise exposure is rapidly becoming a pressing societal and health concern. Phononic and sonic crystals, acoustic metamaterials, and metasurfaces can revolutionize noise and vibration control and, in many cases, replace traditional porous materials for these applications.In this collection of contributed chapters, a group of international researchers reviews the essentials of acoustic wave propagation in metamaterials and porous absorbers with viscothermal losses, as well as the most recent advances in the design of acoustic metamaterial absorbers. The book features a detailed theoretical introduction describing commonly used modelling techniques such as plane wave expansion, multiple scattering theory, and the transfer matrix method. The following chapters give a detailed consideration of acoustic wave propagation in viscothermal fluids and porous media, and the extension of this theory to non-local models for fluid saturated metamaterials, along with a description of the relevant numerical methods. Finally, the book reviews a range of practical industrial applications, making it especially attractive as a white book targeted at the building, automotive, and aeronautic industries.

Ideal for all practitioners of musculoskeletal medicine, this practical pocket guide provides a standardized approach, through detailed checklists and protocols, for a complete ultrasonographic examination of the musculoskeletal system to assist in the diagnosis and management of orthopedic and sports medicine pathologies. As the trend in the US healthcare system continues to move towards optimizaing value in care delivery, the utilization of ultrasound has been in the spotlight as a cost-efficient and accurate diagnostic modality for musculoskeletal pathology  Ultrasound assessment remains user-dependent, and multiple pathologies can often be overlooked due to the lack of a standardized approach to assess a specific joint or anatomic structure. To address this challenge, this user-friendly text presents a quick, accessible, and structured approach for a complete sonographic examination. After a general overview of the use of ultrasound in musculoskeletal medicine, each chapter proceeds anatomically and includes a detailed, step-by-step approach to the ultrasound diagnostic assessment, covering all major joints and pathologies of clinical importance: shoulder, elbow, hand and wrist, hip, knee, and foot and ankle. Plentiful images support this stepwise approach, covering the entire spectrum from patient positioning to ultrasound findings and appearance.  Students, residents, and fellows in orthopedics and sports medicine will find this text especially valuable, however all healthcare providers dealing with the diagnosis and management of musculoskeletal conditions will benefit from its clear and concise approach.

Listening, Belonging, and Memory puts connected listening at the center of current debates around whose voices might be listened to, who by, and why. Arguing that listening has to be understood in relation to the self, nation, age, witnessing, and memory, it uses examples from digital storytelling, listening projects, and critical media analysis to highlight connections between listening and power. It centers on voices, stories, and silence, how they interweave, and are activated, maneuvered, reconfigured, and denied. It focuses on the small, microengagementsthat crouch within the superstructures of violent border control and the censorious policing of sonic citizenry, identifying cracks in the reshuffling of histories and hierarchies that connected listening affords.