Download or read book Sirens written by Source Wikipedia and published by University-Press.org. This book was released on 2013-09 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt: Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Pages: 35. Chapters: ACA Allertor 125, ACA Cyclone, ACA Hurricane, American Signal Corporation, ATI HPSS, Chrysler air raid siren, Civil defense siren, EOWS, Federal 3T22, Federal 500 siren, Federal Signal Corporation, Federal Signal Model 2, Federal Signal Modulator, List of cities with Thunderbolt sirens, List of sirens built by Alerting Communicators of America, Public Warning System, Siren (noisemaker), Stator, STH-10 Siren, Whelen 3000 series, Whelen Engineering Company, Whelen Hornet. Excerpt: A civil defense siren (also colloquially referred to as an air raid or tornado siren) is a mechanical or electronic device (modern-day sirens are electrically powered whether they are electronic or electro-mechanical) for generating sound to provide warning of approaching danger and sometimes to indicate when the danger has passed. In some areas in the United States, civil defense sirens may sound in the late morning and early afternoon on a regular basis. Initially designed to warn of air raids in World War II, they were adapted to warn of nuclear attack and of natural phenomena such as tornadoes. The generalized nature of the siren led to many of them being replaced with more specialized warnings, such as the Emergency Alert System. In a mechanical siren, sound is generated by a motor driving a shaft with a special turbine (known as a rotor or chopper) on one or both ends. It will have only one fan if it is a single-toned siren, while if it is a dual-toned siren, it will have either one fan on each end or two fans in a stack on one end, with one fan having a few more blades than the other. Around each fan-or chopper or rotor-is a housing with a number of rectangular holes to match the number of fan blades. This housing is known as a stator. The end of each blade has a plate whose shape is matched with the rectangular holes and circular...

Download or read book Emergency Vehicle Sirens written by Emergency Warning Lights and Devices Standards Committee and published by . This book was released on 2008 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This SAE Recommended Practice provides laboratory test procedures, requirements and guidelines for electronic siren systems with a single loudspeaker, and electromechanical sirens for use on authorized emergency vehicles, which call for the right-of-way. This document is applicable only to such sirens that have all dimensions across the sound-emitting opening equal to or less than 0.5 m. Test procedures and performance requirements for individual system components are not included in this version.Data obtained from measurements of siren performance depend not only on the characteristics of the siren tested, but additionally on the test procedures and the characteristics of the measurement instrumentation and test environment. These additional factors must be well defined and controlled to obtain reliable data. Detailed test methods are described here, which include specifications for a laboratory environment, to minimize the measurement uncertainty and obtain accurate and reproducible measurement results. Such results are necessary to qualify the performance of all sirens as equally as practicable. Requirements have been established based on the laboratory-measured performance of sirens that have been effective in emergency service.This revision of SAE J1849 was developed during the second phase of a planned three-phase process. Phase one was performed to further develop test procedures and minimum performance requirements for electronic siren systems with a single speaker and electromechanical sirens. Phase two was conducted to specify an additional acoustical test for siren systems with a large speaker or a large speaker array. The intent of phase three will be to specify tests and performance requirements for individual siren components so that an electronic siren system, created from components tested accordingly, will meet the acoustical performance requirements developed during phase one. The primary goal of phase one was to further develop the measurement methods for siren performance specified in Title 13, Article 8 of the California Code of Regulations and previous versions of SAE J1849. As an outcome of phase one, the acoustical measurement methods are specified in more detail and reduce the uncertainty in the results. These methods produce data that are less dependent on the design of the sirens tested, and are more indicative of the sound levels produced across the entire frequency range of the measured signals. Phase one also produced a more comprehensive set of environmental tests than these other documents, acoustical performance re-testing subsequent to these environmental tests, and a specified procedure for the signal frequency measurement. The required warm-up period for the SPL measurement was increased to 10 min in phase one. Measurement results obtained after a ten-minute warm-up period are much less sensitive to the magnetic circuit design of the siren loudspeaker under test (with respect to its thermal properties), since most loudspeakers have more closely approached thermal equilibrium after warming up for 10 min. A 10 min warm-up period also produces measurement results that better represent siren performance during periods of extended use on emergency vehicles. Since the SPL decreases with time as the loudspeaker heats, a longer warm-up period results in measured SPL values that are lower than those measured after only one minute. Acoustical measurement instruments indicate SPL values obtained by averaging continuously over a given period specified by the exponential-time averaging constant, which is commonly referred to as the averaging time. For time-varying signals such as a siren signal, the averaging time will have a direct effect on the range of the fluctuations that occur during the measurement. In order to obtain results derived from the SPL produced across the entire frequency range of the measured signal, a long-term average SPL measurement is specified. This measurement replaced the measurement of the minimum, relatively instantaneous rms value of the SPL. The long-term averaging time was chosen to minimize the range of fluctuations observed when determining the average SPL produced across the entire frequency range of the siren signal measured. Requirements for the SPL measured with the long-term time setting are lower than those measured with the fast time setting since the former measurement averages over the entire signal cycle, which includes more low level portions of the signal that occur over a wider frequency bandwidth. For measurements done with the fast time setting, the requirements for the SPL of faster cycling signals are lower than the requirements for slower cycling signals. This is due to the fact that a much wider bandwidth is sampled over the averaging time used with this setting for faster cycling signals than relatively slower signals. Therefore, with all other parameters equal, a faster cycling signal will produce lower measured maximum rms levels since more low-level portions are included in the sampled signal. To reduce the uncertainty in the acoustical measurements, mechanical level recorders are not specified. These recorders are subject to overshoot, and have variable controls (e.g., writing speed) with nonstandardized settings that can affect the measurement results by changing the effective averaging time of the measurement. Measurements of the SPL produced by a siren off the device axis can be performed by continuously rotating the loudspeaker on a turntable while measuring the SPL at a fixed point. However, using a continuously rotating turntable makes it difficult to accurately determine the SPL produced by a siren loudspeaker as a function of angle since the SPL also varies with time in a cyclic manner. More accurate results are obtained with the turntable paused at each specified angle for a period at least as long as the siren cycle or the instrument averaging time, whichever is longer. The goal of phase two was to develop a test that would determine whether the SPL measured for a given large speaker or speaker array at 3.00 meters can be considered to approximate a far field measurement result. Procedures for performing this test and reducing the acquired data are described in 5.11. Requirements for the test results are specified in 6.11. The procedures for the vibration and corrosion tests specified in 5.2 and 5.3 respectively were revised to cite SAE J575 with no exceptions. Electromagnetic Radiated and Conducted Emissions testing has been updated to reference CISPR 25 as the new radiated and conducted emissions test method since SAE 1113-41 is obsolete.

Download or read book Emergency Vehicle Warning Devices written by United States. National Bureau of Standards. Building Research Division and published by . This book was released on 1972 with total page 122 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Emergency Vehicle Warning Systems written by Arthur I. Rubin and published by . This book was released on 1981 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Devices for Air Raid Warnings written by United States. Bureau of Standards and published by . This book was released on 1942 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book P Z written by Library of Congress. Office for Subject Cataloging Policy and published by . This book was released on 1990 with total page 1644 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Dictionary of Maritime written by Utku Taşova and published by Entropol. This book was released on 2023-11-03 with total page 689 pages. Available in PDF, EPUB and Kindle. Book excerpt: Your Compass to Maritime Mastery As boundless as the oceans, the field of maritime studies has charted the course of human civilization for centuries. It's an ever-evolving realm where the waves of change constantly reshape the contours of knowledge. In this expansive sea of understanding, having a reliable compass is indispensable. The Dictionary of Maritime, with its compendium of 4,645 meticulously curated entries, aims to be that navigational aid guiding enthusiasts, professionals, and scholars alike through the complex waters of maritime terminology. Our journey begins at the shores of basic nautical terms, ventures through the straits of maritime law, navigates the currents of naval architecture, and explores the depths of oceanography. Each entry within this dictionary is akin to a nautical star, guiding readers through the dense fog of maritime jargon towards the clarity of comprehension. The Dictionary of Maritime is far more than a mere collection of definitions; it's a lighthouse illuminating the path for those sailing the tumultuous seas of maritime studies. Whether you are a seasoned mariner, a maritime law scholar, a naval architect, or an oceanography student, this dictionary is designed to bridge the gap between the arcane and the understood, between obscurity and clarity. This book is not merely a passive repository of maritime terms but an active engagement with the rich tapestry of maritime knowledge. Each term, each phrase is a portal into a vast world that has shaped, and continues to shape, the course of human history. The terms encapsulated within these pages are buoy markers on your journey through the expansive waters of maritime understanding. Our endeavor is to foster a shared lexicon, a common ground of understanding that can enhance communication, collaboration, and comprehension across the myriad sectors within the maritime domain. By doing so, we aspire to contribute to the safety, efficiency, and evolution of the maritime world. As you delve into the pages of The Dictionary of Maritime, you are embarking on a voyage of discovery. Each term you encounter is a nautical mile on your journey towards a deeper understanding of the world that lies beyond the horizon. We invite you to hoist the sails of curiosity and let the winds of knowledge guide you through the enlightening pages of The Dictionary of Maritime. May your quest for understanding be as boundless as the oceans and may your exploration through these entries chart a course towards a lifetime of learning in the maritime realm.

Download or read book Reading Sounds written by Sean Zdenek and published by University of Chicago Press. This book was released on 2015-12-23 with total page 357 pages. Available in PDF, EPUB and Kindle. Book excerpt: The work of writing closed captions for television and DVD is not simply transcribing dialogue, as one might assume at first, but consists largely of making rhetorical choices. For Sean Zdenek, when captioners describe a sound they are interpreting and creating contexts, they are assigning significance, they are creating meaning that doesn t necessarily exist in the soundtrack or the script. And in nine chapters he analyzes the numerous complex rhetorical choices captioners make, from abbreviating dialogue so it will fit on the screen and keep pace with the editing, to whether and how to describe background sounds, accents, or slurred speech, to nonlinguistic forms of sound communication such as sighing, screaming, or laughing, to describing music, captioned silences (as when a continuous noise suddenly stops), and sarcasm, surprise, and other forms of meaning associated with vocal tone. Throughout, he also looks at closed captioning style manuals and draws on interviews with professional captioners and hearing-impaired viewers. Threading through all this is the novel argument that closed captions can be viewed as texts worthy of rhetorical analysis and that this analysis can lead the entertainment industry to better standards and practices for closed captioning, thereby better serve the needs of hearing-impaired viewers. The author also looks ahead to the work yet to be done in bringing better captioning practices to videos on the Internet, where captioning can take on additional functions such as enhancing searchability. While scholarly work has been done on captioning from a legal perspective, from a historical perspective, and from a technical perspective, no one has ever done what Zdenek does here, and the original analytical models he offers are richly interdisciplinary, drawing on work from the fields of technical communication, rhetoric, media studies, and disability studies."

Download or read book Library of Congress Subject Headings written by Library of Congress and published by . This book was released on 2013 with total page 1164 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Library of Congress Subject Headings written by Library of Congress. Office for Subject Cataloging Policy and published by . This book was released on 1991 with total page 1580 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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Download or read book Summary Report on Emergency Vehicle Sirens written by Frank Edward Jones and published by . This book was released on 1975 with total page 60 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Development and Testing of a Highly Directional Dual mode Electronic Siren written by Ronald L. Fisher and published by . This book was released on 1978 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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Download or read book Supplement to LC Subject Headings written by Library of Congress. Subject Cataloging Division and published by . This book was released on 1974 with total page 388 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Effectiveness of Sonic Outdoor Warning Devices written by Stanford Research Institute and published by . This book was released on 1953 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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