出版: | Washington, DC : National Science Foundation |
出版: | Springfield, VA : Distributed by NTIS, National Technical Information Service, U.S. Dept. of Commerce |
出版: | Washington : Office of Naval Research |
出版: | San Diego, Calif. : Naval Undersea Center |
出版: | Washington : U. S. Dept. of Commerce, National Oceanic and Atmospheric Administration, National Marine Fisheries Service ; for sale by the Supt. of Docs., U. S. Govt. Print. Off. |
出版: | Washington : U.S. Govt. Print. Off. |
附註: | Reuse of record except for individual research requires license from Congressional Information Service, Inc. "Printed for the use of the [House] Committee on Merchant Marine and Fisheries." At head of title: Committee print. CIS Microfiche Accession Numbers: CIS 73 H562-10 Microfiche.[Bethesda, Md.] :Congressional Information Service,197311 X 15 cm. [microform]. |
出版: | Washington, D.C. : U.S. Govt. Print. Off. |
出版: | Washington : U.S. Govt. Print. Off. |
附註: | Reuse of record except for individual research requires license from Congressional Information Service, Inc. "Serial no. 93-1." CIS Microfiche Accession Numbers: CIS 73 H561-6 Microfiche.[Bethesda, Md.] :Congressional Information Service,197311 X 15 cm. [microform] |
出版: | Washington : U.S. Govt. Print. Off. |
附註: | Reuse of record except for individual research requires license from Congressional Information Service, Inc. "Serial no. 93-14." CIS Microfiche Accession Numbers: CIS 73 H561-19 Microfiche.[Bethesda, Md.] :Congressional Information Service,197311 X 15 cm. [microform] |
出版: | Washington : U.S. Govt. Print. Off. |
出版: | Washington : National Oceanographic Center. |
ISBN: | 0091-9500 |
附註: | Nos. 1-6 issued by the Environmental Data Service; 7- issued by the Environmental Data and Information Service. |
出版: | [Washington, D.C.] : U.S. Dept. of Commerce, National Oceanic and Atmospheric Administration, Environmental Data Service |
出版: | Highlands, N.J. : National Marine Fisheries Service : Middle Atlantic Coastal Fisheries Center |
出版: | Seattle, Washington : National Marine Fisheries Service. |
出版: | Washington, D.C. : [Springfield, Va. : National Aeronautics and Space Administration ; For sale by the National Technical Information Service] |
附註: | Prepared at the NASA Flight Research Center. Cover title. Includes bibliographical references (p. 9-10). Measurements of engine noise generated by an F-111A airplane positioned on a thrustmeasuring platform were made at angles of 0 deg to 160 deg from the aircraft heading. Sound power levels, power spectra, and directivity patterns are presented for jet exit velocities between 260 feet per second and 2400 feet per second. The test results indicate that the total acoustic power was proportional to the eighth power of the core jet velocity for core exhaust velocities greater than 300 meters per second (985 feet per second) and that little or no mixing of the core and fan streams occurred. The maximum sideline noise was most accurately predicted by using the average jet velocity for velocities above 300 meters per second (985 feet per second). The acoustic power spectrum was essentially the same for the single jet flow of afterburner operation and the coaxial flow of the nonafterburning condition. By varying the inlet geometry and cowl position, reductions in the sound pressure level of the blade passing frequency on the order of 15 decibels to 25 decibels were observed for inlet Mach numbers of 0.8 to 0.9 System requirements: Adobe Acrobat Reader. [electronic resource] |
出版: | Washington, D.C. : [Springfield, Va. : National Aeronautics and Space Administration ; For sale by the National Technical Information Service] |
附註: | Prepared at Langley Research Center. Cover title. Bibliography: p. 14 An experiment was performed to measure the transmission losses of sound waves traversing an impedance layer. The sound emanated from a point source and the impedance layer was created by a low-speed helium jet. The transmission losses measured were of the order of 12 db for frequencies of the source between 4 and 12 kHz. These losses are greater than those predicted from analysis when the observer angle is less than about 35 deg, but less than those predicted for larger observer angles. The experimental results indicate that appreciable noise reductions can be realized for an observer shielded by an impedance layer, irrespective of his position relative to the source of sound. System requirements: Adobe Acrobat Reader. [electronic resource] |
出版: | Washington : U.S. Govt. Print. Off. |
附註: | Reuse of record except for individual research requires license from Congressional Information Service, Inc. "Serial no. 93-13." Hearings on H.R. 4756, 4760, 5447, 6074, 6931, 7231, and 7649 CIS Microfiche Accession Numbers: CIS 73 H561-20 Microfiche.[Bethesda, Md.] :Congressional Information Service,197311 X 15 cm. [microform] |
出版: | Seattle : Washington, D.C. : National Oceanic and Atmospheric Administration ; for sale by the Superintendent of Documents, U.S. G.P.O. |
附註: | "April 1973" "Proceedings of a workshop sponsored by the Division of Economic Research, National Marine Fisheries Service, November 5-6, 1970." Includes bibliographies. |
出版: | [Washington : |
附註: | Publication date stamped on t.p. "B-177024." Cover title. |
出版: | [Concord, N.H. ?] : The Dept. |
出版: | Washington, [D.C.] : National Marine Fisheries Service |
ISBN: | 0093-8327 |
出版: | Washington : U.S. Govt. Print. Off. |
附註: | Reuse of record except for individual research requires license from Congressional Information Service, Inc. "Serial no. 93-11." CIS Microfiche Accession Numbers: CIS 73 H561-18 Microfiche.[Bethesda, Md.] :Congressional Information Service,197311 X 15 cm. [microform] |
出版: | Washington : U.S. Govt. Print. Off. |
出版: | Washington : U.S. Govt. Print. Off. |
出版: | Seattle, WA : Washington, D.C. : U.S. Dept. of Commerce, National Oceanic and Atmospheric Administration, National Marine Fisheries Service ; for sale by the Superintendent of Documents, U.S. G.P.O. |
附註: | "July 1973." |
出版: | Seattle, WA : Washington, D.C. : U.S. Dept. of Commerce, National Oceanic and Atmospheric Administration, National Marine Fisheries Service ; for sale by the Superintendent of Documents, U.S. G.P.O. |
附註: | "May 1973." |
出版: | Seattle, WA : Washington, D.C. : U.S. Dept. of Commerce, National Oceanic and Atmospheric Administration, National Marine Fisheries Service ; for sale by the Superintendent of Documents, U.S. G.P.O. |
附註: | "July 1973." |
出版: | Seattle, WA : Washington, D.C. : U.S. Dept. of Commerce, National Oceanic and Atmospheric Administration, National Marine Fisheries Service ; for sale by the Superintendent of Documents, U.S. G.P.O. |
附註: | "July 1973." |
出版: | Seattle, WA : Washington, D.C. : U.S. Dept. of Commerce, National Oceanic and Atmospheric Administration, National Marine Fisheries Service ; for sale by the Superintendent of Documents, U.S. G.P.O. |
附註: | "November 1973." |
出版: | Seattle, WA : U.S. Dept. of Commerce, National Oceanic and Atmospheric Administration, National Marine Fisheries Service |
附註: | "April 1973." |
出版: | Seattle : National Oceanic and Atmospheric Administration |
ISBN: | 0093-4917 |
出版: | Seattle, Wash. : Washington, D.C. : U.S. Dept. of Commerce, National Oceanic and Atmospheric Administration, National Marine Fisheries Service ; For sale by the Supt. of Docs., U.S.G.P.O. |