On the improvement measures of interior noise reduction of minivan’s roof based on acoustic modal analysis

In this work, three types of measures, i.e., 1) adding the damping adhesive, 2) changing the local beads and 3) utilizing the dynamic vibration absorber (DVA), are performed to investigate and improve the acoustic quality of the minivan’s interior noise. For adding the damping adhesive, the difference of the adhesive location directly affects the mode of minivan’s roof. For changing the local beads, eight cases of beads are selected. The results indicate that the change trend of the first natural frequency is parabolic as the number of beads increases. For adding the 33 Hz DVA, the results show that the sound pressure levels (SPLs) of the minivan’s response points located at the front, middle and rear seat in the critical frequency are approximately reduced by 2.1 dB, 1.5 dB and 1.1 dB in the minivan’s simulation, and by 2.6 dB(A), 1.4 dB(A) and 2.7 dB(A) in the minivan’s road experiment, respectively. By contrast, the DVA with a certain frequency should be chosen if the reduction of sound pressure level (SPL) is only considered. Furthermore, if the SPL’s reduction and the additional mass are taken into account at the same time, the measure with local flatted beads should be selected. The obtained results could provide a certain practical guiding significance for improving the mode and interior noise of minivan’s roof

NASA Tech Briefs, February 1997

Topics include: Test and Measurement; Electronic Components and Circuits; Electronic Systems; Physical Sciences; Materials; Computer Programs; Mechanics; Machinery/Automation; Manufacturing/Fabrication; Mathematics and Information Sciences; Life Sciences; Books and Report

Abstracts on Radio Direction Finding (1899 - 1995)

The files on this record represent the various databases that originally composed the CD-ROM issue of "Abstracts on Radio Direction Finding" database, which is now part of the Dudley Knox Library's Abstracts and Selected Full Text Documents on Radio Direction Finding (1899 - 1995) Collection. (See Calhoun record https://calhoun.nps.edu/handle/10945/57364 for further information on this collection and the bibliography). Due to issues of technological obsolescence preventing current and future audiences from accessing the bibliography, DKL exported and converted into the three files on this record the various databases contained in the CD-ROM. The contents of these files are: 1) RDFA_CompleteBibliography_xls.zip [RDFA_CompleteBibliography.xls: Metadata for the complete bibliography, in Excel 97-2003 Workbook format; RDFA_Glossary.xls: Glossary of terms, in Excel 97-2003 Workbookformat; RDFA_Biographies.xls: Biographies of leading figures, in Excel 97-2003 Workbook format]; 2) RDFA_CompleteBibliography_csv.zip [RDFA_CompleteBibliography.TXT: Metadata for the complete bibliography, in CSV format; RDFA_Glossary.TXT: Glossary of terms, in CSV format; RDFA_Biographies.TXT: Biographies of leading figures, in CSV format]; 3) RDFA_CompleteBibliography.pdf: A human readable display of the bibliographic data, as a means of double-checking any possible deviations due to conversion

NASA Tech Briefs, Summer 1978, Volume 3, No. 2

Topics covered include: NASA TU Services: Technology Utilization services that can assist you in learning about and applying NASA technology; New Product Ideas: A summary of selected innovations of value to manufacturers for the development of new products; Electronic Components and Circuits; Electronic Systems; Physical Sciences; Solar Energy; Materials; Life Sciences; Mechanics; Machinery; Fabrication Technology; Mathematics and Information Sciences

Intelligent Circuits and Systems

ICICS-2020 is the third conference initiated by the School of Electronics and Electrical Engineering at Lovely Professional University that explored recent innovations of researchers working for the development of smart and green technologies in the fields of Energy, Electronics, Communications, Computers, and Control. ICICS provides innovators to identify new opportunities for the social and economic benefits of society.　 This conference bridges the gap between academics and R&D institutions, social visionaries, and experts from all strata of society to present their ongoing research activities and foster research relations between them. It provides opportunities for the exchange of new ideas, applications, and experiences in the field of smart technologies and finding global partners for future collaboration. The ICICS-2020 was conducted in two broad categories, Intelligent Circuits & Intelligent Systems and Emerging Technologies in Electrical Engineering

Research and Technology 1990

A brief but comprehensive review is given of the technical accomplishments of the NASA Lewis Research Center during the past year. Topics covered include instrumentation and controls technology; internal fluid dynamics; aerospace materials, structures, propulsion, and electronics; space flight systems; cryogenic fluids; Space Station Freedom systems engineering, photovoltaic power module, electrical systems, and operations; and engineering and computational support