{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,26]],"date-time":"2025-10-26T20:56:00Z","timestamp":1761512160789},"reference-count":0,"publisher":"Acoustical Society of America (ASA)","issue":"1","content-domain":{"domain":["pubs.aip.org"],"crossmark-restriction":true},"short-container-title":[],"published-print":{"date-parts":[[1993,7,1]]},"abstract":"<jats:p>Contact sensors to monitor fetal heart, breathing, and movement sounds with increased sensitivity and bandwidth are under development. To understand the inherent acoustical properties of the maternal abdomen and its interaction with these sensors, the driving-point impedance Z(j\u03c9) was measured in nine women during their last trimester of pregnancy. An electromechanical shaker with a contact area of 2.85 cm2 produced abdominal vibrations between 10 and 500 Hz, and the resulting force and acceleration were measured. After digitally integrating the acceleration signal to obtain the velocity and removing the massive effects of the coupling between the shaker and the abdomen, Z(j\u03c9) was estimated using spectral techniques. The imaginary part of Z(j\u03c9) depicted a dominant compliance effect at low frequencies, a resonance at a frequency of 28\u00b116 Hz (mean\u00b1s.d.), and a dominant mass effect at higher frequencies. The real part of Z(j\u03c9) increased steadily with frequency. A series resistance-mass-compliance (R-M-C) circuit modeled these characteristics of Z(j\u03c9) well when R was allowed to exactly mimic the frequency dependence of the real part of Z(j\u03c9). Estimated element values of 6.6\u00b12.2\u00d710\u22123 kg for M, 2.1\u00b11.4\u00d710\u22123 m\/N for C, and roughly 10 Ns\/m for R (at resonance) were similar to those estimated for other body tissues such as the thigh but quite different from that of the often-studied chest wall.<\/jats:p>","DOI":"10.1121\/1.408220","type":"journal-article","created":{"date-parts":[[2005,10,13]],"date-time":"2005-10-13T21:04:32Z","timestamp":1129237472000},"page":"13-18","update-policy":"http:\/\/dx.doi.org\/10.1063\/aip-crossmark-policy-page","source":"Crossref","is-referenced-by-count":5,"title":["Acoustic impedance of the maternal abdomen"],"prefix":"10.1121","volume":"94","author":[{"given":"George R.","family":"Wodicka","sequence":"first","affiliation":[{"name":"School of Electrical Engineering and Hillenbrand Biomedical Engineering Center, Purdue University, West Lafayette, Indiana 47907-1285"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Alison M.","family":"Lam","sequence":"additional","affiliation":[{"name":"School of Electrical Engineering and Hillenbrand Biomedical Engineering Center, Purdue University, West Lafayette, Indiana 47907-1285"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Vinay","family":"Bhargava","sequence":"additional","affiliation":[{"name":"School of Electrical Engineering and Hillenbrand Biomedical Engineering Center, Purdue University, West Lafayette, Indiana 47907-1285"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Daniel","family":"Sunkel","sequence":"additional","affiliation":[{"name":"Women\u2019s Clinic, Lafayette, Indiana 47905"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"231","container-title":["The Journal of the Acoustical Society of America"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/pubs.aip.org\/asa\/jasa\/article-pdf\/94\/1\/13\/11927458\/13_1_online.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"syndication"},{"URL":"https:\/\/pubs.aip.org\/asa\/jasa\/article-pdf\/94\/1\/13\/11927458\/13_1_online.pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2023,8,4]],"date-time":"2023-08-04T08:25:11Z","timestamp":1691137511000},"score":1,"resource":{"primary":{"URL":"https:\/\/pubs.aip.org\/jasa\/article\/94\/1\/13\/970904\/Acoustic-impedance-of-the-maternal-abdomenAcoustic"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1993,7,1]]},"references-count":0,"journal-issue":{"issue":"1","published-print":{"date-parts":[[1993,7,1]]}},"URL":"https:\/\/doi.org\/10.1121\/1.408220","relation":{},"ISSN":["0001-4966","1520-8524"],"issn-type":[{"value":"0001-4966","type":"print"},{"value":"1520-8524","type":"electronic"}],"subject":[],"published-other":{"date-parts":[[1993,7]]},"published":{"date-parts":[[1993,7,1]]}}}