摘要:

Abstract not available.

ISSN:0001-4966    

DOI:10.1121/1.417345

出版商:Acoustical Society of America    

年代:1996

数据来源: AIP

ISSN:0001-4966    

DOI:10.1121/1.416254

出版商:Acoustical Society of America    

年代:1996

数据来源: AIP

摘要:

Abstract not available.

ISSN:0001-4966    

DOI:10.1121/1.416255

出版商:Acoustical Society of America    

年代:1996

数据来源: AIP

ISSN:0001-4966    

DOI:10.1121/1.416259

出版商:Acoustical Society of America    

年代:1996

数据来源: AIP

ISSN:0001-4966    

DOI:10.1121/1.416260

出版商:Acoustical Society of America    

年代:1996

数据来源: AIP

摘要:

The purpose of these acoustical patent reviews is to provide enough information for a Journal reader to decide whether to seek more information from the patent itself. Any opinions expressed here are those of the reviewers as individuals and are not legal opinions. Printed copies of United States Patents may be ordered at $3.00 each from the Commissioner of Patents and Trademarks, Washington, DC 20231. Patents are available via the Internet athttp://www.uspto.gov.

ISSN:0001-4966    

DOI:10.1121/1.416310

出版商:Acoustical Society of America    

年代:1996

数据来源: AIP

摘要:

Editorialnote: This invited and tutorial article is being published in three parts. The abstract for the series was published in Part I—Piano hammers and tonal effects [J. Acoust. Soc. Am.99, 3286–3296 (1996)].

ISSN:0001-4966    

DOI:10.1121/1.416233

出版商:Acoustical Society of America    

年代:1996

数据来源: AIP

摘要:

A calculation method is presented for transducer‐generated three‐dimensional, transient wave fields in layered media with curved interfaces by using a separation approach in combination with integral transform methods and point source synthesis. The transducer‐specimen module is decomposed into different layers and the wave propagation is calculated separately in each layer. To simplify the boundary conditions, the existence of a thin liquid layer between two solid media is used. Using generalized ray theory it can be shown that the normal stress on the interface caused by an incident wave provides sufficient information to calculate the transmitted waves in the adjacent media. Two different functions for the point sources of the exciting element and the source function for normal stress are derived. By means of a source function for normal stress, the transmitted transient wave can be determined from the normal‐stress distribution on the interface. The method is demonstrated by two examples.

ISSN:0001-4966    

DOI:10.1121/1.416219

出版商:Acoustical Society of America    

年代:1996

数据来源: AIP

摘要:

A method for the measurement of flow rate in a pipe is proposed. The method utilizes the vibration signals that are generated using an external excitor. Three accelerometers on the surface of a pipe are used to measure these signals. Applying wave decomposition theory to the measured vibration signal, change of wave number, which is one of the results caused by flow rate change, is estimated. The change of wave number is converted into flow rate using the simple mathematical model of fluid conveying pipe. The main advantage of this method is that it does not require any sensory system inside the pipe, so that the characteristics of flow are not disturbed and the measurement position can be easily moved. All possible errors associated with the proposed measurement system are investigated. Those are due to sensor spacing, relative position of sensor with respect to boundaries, phase mismatch as well as magnitude mismatch between sensors, and measurement noise. To verify the potential of this method, experiments using water conveying steel pipe are accomplished. Finally, the estimated flow rates are within 12% error bounds.

ISSN:0001-4966    

DOI:10.1121/1.416211

出版商:Acoustical Society of America    

年代:1996

数据来源: AIP

摘要:

In a linear approximation, an arbitrary axial‐symmetric source can be expressed as the linear superposition of a set of Gaussian sources and the corresponding radiated sound field can be represented as the superposition of this set of Gaussian beams. The analysis is extended to the second harmonic generation due to nonlinear effects under a quasilinear approximation, then the second harmonic sound field could be considered as a sum of self‐ and cross‐interaction terms produced by a series of Gaussian beams. Therefore, the calculation of the second harmonic sound field of an axial‐symmetric source can be reduced to a simple linear combination of a set of exponential integral functions, instead of a complicated triple integral. In order to verify this calculation approach, the second harmonic generation of a focused and a simple piston source is examined, and the result is in good agreement with that in earlier paper by complicated computation.

ISSN:0001-4966    

DOI:10.1121/1.416234

出版商:Acoustical Society of America    

年代:1996

数据来源: AIP