A Seismic/acoustic Study of Low Altitude Air Blasts at Ft. Devens, Massachusetts PDF Download
Are you looking for read ebook online? Search for your book and save it on your Kindle device, PC, phones or tablets. Download A Seismic/acoustic Study of Low Altitude Air Blasts at Ft. Devens, Massachusetts PDF full book. Access full book title A Seismic/acoustic Study of Low Altitude Air Blasts at Ft. Devens, Massachusetts by Janet C. Johnston. Download full books in PDF and EPUB format.
Author: Janet C. Johnston
Publisher:
ISBN:
Category : Blast effect
Languages : en
Pages : 98
Get Book Here
Book Description
On 5 May 1986, 3 packages of TNT were detonated 100 ft in the air above the Turner Drop Zone at Ft. Devens, Massachusetts. The aerial explosions were recorded by seismic and acoustic sensors over 2 linear arrays that covered the distance range from 0 to 1000 meters. One array was installed over flat topography, while the other was installed across a hill with 80 ft of relief. The goal of the experiment was to examine the response of the ground and the air to a unit impulse. Although recording of the higher frequencies generated by the blasts was limited by the sampling rate capability of the equipment (100 and 200 samples/sec) it was clear that the hill produced a sheltering effect. Considerable transverse motion appeared in the records. Reduced time plots revealed a propagation speed of 0.35 km/sec corresponding primarily to an airwave induced seismic signal, although some seismic precursors are evident. The ratio of peak seismic velocity to pressure ranged from 10-4 cm/sec/Pa for the line that transversed the hill to .00001 cm/sec/Pa for the flat array. The experiment should be repeated in the same area during different seasonal coverings (snow and ice) and extended to areas with more complex topography and different vegetation. In future experiments the position of the air blasts should be varied to facilitate discrimination of paths to the receivers. The results could be extrapolated to an extended, continuous source such as a low flying aircraft or cruise missile.
Author: Janet C. Johnston
Publisher:
ISBN:
Category : Blast effect
Languages : en
Pages : 98
Get Book Here
Book Description
On 5 May 1986, 3 packages of TNT were detonated 100 ft in the air above the Turner Drop Zone at Ft. Devens, Massachusetts. The aerial explosions were recorded by seismic and acoustic sensors over 2 linear arrays that covered the distance range from 0 to 1000 meters. One array was installed over flat topography, while the other was installed across a hill with 80 ft of relief. The goal of the experiment was to examine the response of the ground and the air to a unit impulse. Although recording of the higher frequencies generated by the blasts was limited by the sampling rate capability of the equipment (100 and 200 samples/sec) it was clear that the hill produced a sheltering effect. Considerable transverse motion appeared in the records. Reduced time plots revealed a propagation speed of 0.35 km/sec corresponding primarily to an airwave induced seismic signal, although some seismic precursors are evident. The ratio of peak seismic velocity to pressure ranged from 10-4 cm/sec/Pa for the line that transversed the hill to .00001 cm/sec/Pa for the flat array. The experiment should be repeated in the same area during different seasonal coverings (snow and ice) and extended to areas with more complex topography and different vegetation. In future experiments the position of the air blasts should be varied to facilitate discrimination of paths to the receivers. The results could be extrapolated to an extended, continuous source such as a low flying aircraft or cruise missile.
Author:
Publisher:
ISBN:
Category : Environmental geology
Languages : en
Pages : 196
Get Book Here
Book Description
Author: R. G. Cameron
Publisher:
ISBN:
Category : Analog multipliers
Languages : en
Pages : 194
Get Book Here
Book Description
The development is described of fabrication techniques for construction of a silicon Hall effect element with characteristics suitable for application in an analog multiplier. The relative merits of various semiconductor materials are considered, and the reasons for the selection of silicon are outlined. The considerations necessary for the design of the element package structure are developed, and the tests required to characterize the Hall element in terms of electronic design parameters are also developed. Approximately 24 successful silicon elements were processed, and three pairs were mounted in suitable magnetic structures so as to obtain complete element packages. Experimental transistorized circuitry was constructed for use with these element packages in order to exhibit the ability of the silicon Hall device to multiply. (Author).
Author:
Publisher:
ISBN:
Category : Government reports announcements & index
Languages : en
Pages : 1126
Get Book Here
Book Description
Author:
Publisher:
ISBN:
Category : Government publications
Languages : en
Pages : 1270
Get Book Here
Book Description
Author: Air Corps. War Department
Publisher:
ISBN:
Category :
Languages : en
Pages : 626
Get Book Here
Book Description
Author:
Publisher: Department of the Army
ISBN:
Category : History
Languages : en
Pages : 202
Get Book Here
Book Description
A History of Army Communications and Electronics at Fort Monmouth, New Jersey, 1917-2007 chronicles ninety years of communications-electronics achievements carried out by the scientists, engineers, logisticians and support staff at Fort Monmouth, NJ. From homing pigeons to frequency hopping tactical radios, the personnel at Fort Monmouth have been at the forefront of providing the U.S. Army with the most reliable systems for communicating battlefield information. Special sections of the book are devoted to ground breaking achievements in "Famous Firsts", as well as "Celebrity Notes", a rundown on the notable and notorious figures in Fort Monmouth history. The book also includes information on commanding officers, tenants and post landmarks.
Author: James Bamford
Publisher: Anchor
ISBN: 0307425053
Category : Political Science
Languages : en
Pages : 782
Get Book Here
Book Description
The National Security Agency is the world’s most powerful, most far-reaching espionage. Now with a new afterword describing the security lapses that preceded the attacks of September 11, 2001, Body of Secrets takes us to the inner sanctum of America’s spy world. In the follow-up to his bestselling Puzzle Palace, James Banford reveals the NSA’s hidden role in the most volatile world events of the past, and its desperate scramble to meet the frightening challenges of today and tomorrow. Here is a scrupulously documented account—much of which is based on unprecedented access to previously undisclosed documents—of the agency’s tireless hunt for intelligence on enemies and allies alike. Body of secrets is a riveting analysis of this most clandestine of agencies, a major work of history and investigative journalism. A New York Times Notable Book
Author: Ray Horak
Publisher: John Wiley & Sons
ISBN: 1118585801
Category : Technology & Engineering
Languages : en
Pages : 795
Get Book Here
Book Description
For an accessible and comprehensive survey of telecommunications and data communications technologies and services, consult the Telecommunications and Data Communications Handbook, which includes information on origins, evolution and meaningful contemporary applications. Find discussions of technologies set in context, with details on fiber optics, cellular radio, digital carrier systems, TCP/IP, and the Internet. Explore topics like Voice over Internet Protocol (VoIP); 802.16 & WiMAX; Passive Optical Network (PON); 802.11g & Multiple Input Multiple Output (MIMO) in this easily accessible guide without the burden of technical jargon.
Author: A. L. Greig
Publisher:
ISBN:
Category : Nevada National Security Site (Nev.)
Languages : en
Pages : 36
Get Book Here
Book Description
