Tag Archives: Underwater Acoustic and Sonar

Underwater Acoustics for Biologists and Conservation Managers

Blue Whale was Tracked for Forty Three Days in North Atlantic Ocean

Video Clip: Click to Watch
A COMPREHENSIVE TUTORIAL DESIGNED

 

FOR ENVIRONMENTAL PROFESSIONALS

Different species of whales and dolphins produce different sounds, such as songs, moans, clicks, roars, sighs, and many other characteristic noises. Each species is unique in its vocalizations. Scientists can listen for these sounds and track the different marine mammal species, and sometimes even individual animals, while they are producing sound.

This four-day course from the Applied Technology Institute (ATI) is designed for biologists, and conservation managers, who wish to enhance their understanding of the underlying principles of underwater and engineering acoustics needed to evaluate the impact of anthropogenic noise on marine life.

This course provides a framework for making objective assessments of the impact of various types of sound sources. Critical topics are introduced through clear and readily understandable heuristic models and graphics. After taking this course you will have the knowledge to perform basic assessments of the impact of anthropogenic sources on marine life in specific ocean environments, and to understand the uncertainties in your assessments.

UNDERWATER ACOUSTICS FOR BIOLOGISTS AND CONSERVATION MANAGERS: A COMPREHENSIVE TUTORIAL DESIGNED FOR ENVIRONMENTAL PROFESSIONALS

What You Will Learn:

What are the key characteristics of man-made sound sources and usage of correct metrics?

How to evaluate the resultant sound field from impulsive, coherent and continuous sources.

How are system characteristics measured and calibrated?

What animal characteristics are important for assessing both impact and requirements for monitoring/and mitigation?

Capabilities of passive and active monitoring and mitigation systems.

Course Outline:

• The Language of Physics and the Study of Motion This quick review of physics basics is designed to introduce acoustics to the neophyte.

• What Is Sound and How To Measure Its Level The properties of sound are described, including the challenging task of properly measuring and reporting its level.

• Digital Representation of Sound Today, almost all sound is recorded and analyzed digitally. This section focuses on the process by which analog sound is digitized, stored and analyzed.

• Spectral Analysis: A Qualitative Introduction The fundamental process for analyzing sound is spectral analysis. This section will introduce spectral analysis and illustrate its application in creating frequency spectra and spectrograms.

• Basics of Underwater Propagation and Use of Acoustic Propagation Models The fundamental principles of geometric spreading, refraction, boundary effects and absorption will be introduced and illustrated using propagation models.

• Review of the Ocean Anthropogenic Noise Issue Current state of knowledge and key references summarizing scientific findings to date.

• Basic Characteristics of Anthropogenic Sound Sources Impulsive (airguns, pile drivers, explosives), Coherent (sonars, acoustic modems, depth sounder. profilers), Continuous (shipping, offshore industrial activities).

• Marine Wildlife of Interest & Their Characteristics Marine mammals, turtles, fish and invertebrates, Bioacoustics, hearing threshold, vocalization behavior. Supporting databases on seasonal density, distribution & movement.

• Assessment of the Impact of Anthropogenic Sound Source-transmission-receiver approach. Level of sound as received by the wildlife, injury, behavioral response, TTS, PTS, Masking. Modeling Techniques, Field Measurements Assessment Methods.

• Monitoring and Mitigation Techniques Passive Devices (fixed and towed systems), Active Devices, Matching Device Capabilities to Environmental Requirements (examples of passive and active localization, long term monitoring, fish exposure testing).

• Overview of Current Research Efforts

Click here for a slide sampler of this course

Your Instructors for this Course:

Dr. Adam S. Frankel is a senior scientist with Marine Acoustics, Inc., Arlington, VA and vice-president of the Hawai’i Marine Mammal Consortium. For the past 25 years, his primary research has focused on the role of natural sounds in marine mammals and the effects of anthropogenic sounds on the marine environment, especially the impact on marine mammals. A graduate of the College of William and Mary, Dr. Frankel received his M.S. and Ph.D. degrees from the University of Hawai’i at Manoa, where he studied and recorded the sounds of humpback whales. Post-doctoral work was with Cornell University’s Bioacoustics Research Program. Published research includes a recent paper on melon-headed whale vocalizations. Both scientist and educator, Frankel combines his Hawai’i – based research and acoustics expertise with teaching for Cornell University and other schools. He has advised numerous graduate students, all of whom make him proud. Frankel is a member of both the Society for the Biology of Marine Mammals and the Acoustical Society of America.

Dr. William T. Ellison is president of Marine Acoustics, Inc., Middletown, RI. Dr. Ellison has over 45 years of field and laboratory experience in underwater acoustics spanning sonar design, ASW tactics, software models and biological field studies. He is a graduate of the Naval Academy and holds the degrees of MSME and Ph.D. from MIT. He has published numerous papers in the field of acoustics and is a co-author of the 2007 monograph Marine Mammal Noise Exposure Criteria: Initial Scientific Recommendations, as well as a member of the ASA Technical Working Group on the impact of noise on Fish and Turtles. He is a Fellow of the Acoustical Society of America and a Fellow of the Explorers Club.

About ATI and the Instructors

Since 1984, ATI has provided leading-edge public courses and onsite technical training. Whether you are a busy engineer, a technical expert or a project manager, you can enhance your understanding of complex systems in a short time. You will become aware of the basic vocabulary essential to interact meaningfully with your colleagues.

Our mission here at ATI is to provide expert training and the highest quality professional development in space, communications, defense, sonar, radar, and signal processing. We are not a one-size-fits-all educational facility. Our short classes include both introductory and advanced courses.

ATI’s instructors are world-class experts who are the best in the business. They are carefully selected for their ability to clearly explain advanced technology.

Times, Dates, and Locations

This course is currently scheduled for:

October 17-20, 2011 in Seattle, WA

For the times, dates and locations of all of our short courses, please access the links below.

Sincerely,

The ATI Courses Team

P.S. Call today for registration at 410-956-8805 or 888-501-2100 or access our website at www.ATIcourses.com. For general questions please email us at ATI@ATIcourses.com.


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Top Five ATI Technical Short Courses for 2010

Applied Technology Institute (ATI)

 

Video Clip: Click to Watch

 

ATI specializes in short course technical training 

Since 1984, ATI has provided leading-edge public courses and onsite technical training to DoD and NASA personnel, as well as contractors. ATI short courses are designed to help you keep your professional knowledge up-to-date. 

Our courses provide you a practical overview of space and defense technologies which provide a strong foundation for understanding the issues that must be confronted in the use, regulation and development such complex systems. 

Our short courses are designed for individuals involved in planning, designing, building, launching, and operating space and defense systems. Whether you are a busy engineer, a technical expert or a project manager, you can enhance your understanding of complex systems in a short time. You will also become aware of the basic vocabulary essential to interact meaningfully with your colleagues. 

The five courses highlighted below were our most popular offerings in 2010. To see the complete course listing from ATI, click on the links at the bottom of the page. 

SATELLITE COMMUNICATION SYSTEMS ENGINEERING COURSE 

This three-day course is designed for satellite communications engineers, spacecraft engineers, and managers who want to obtain an understanding of the “big picture” of satellite communications. Each topic is illustrated by detailed worked numerical examples, using published data for actual satellite communications systems. The course is technically oriented and includes mathematical derivations of the fundamental equations. It will enable the participants to perform their own satellite link budget calculations. The course will especially appeal to those whose objective is to develop quantitative computational skills in addition to obtaining a qualitative familiarity with the basic concepts. 

See a sample of the Satellite Communications Systems Engineering Course on YouTube 

See a slide sampler for the Satellite Communications Systems Engineering Course 

ANTENNA AND ANTENNA ARRAY FUNDAMENTALS 

This three-day course teaches the basics of antenna and antenna array theory. Fundamental concepts such as beam patterns, radiation resistance, polarization, gain/directivity, aperture size, reciprocity, and matching techniques are presented. Different types of antennas such as dipole, loop, patch, horn, dish, and helical antennas are discussed and compared and contrasted from a performance – applications standpoint. The locations of the reactive near-field, radiating near-field (Fresnel region), and far-field (Fraunhofer region) are described and the Friis transmission formula is presented with worked examples. Propagation effects are presented. Antenna arrays are discussed, and array factors for different types of distributions (e.g., uniform, binomial, and Tschebyscheff arrays) are analyzed giving insight to sidelobe levels, null locations, and beam broadening (as the array scans from broadside.) The end-fire condition is discussed. Beam steering is described using phase shifters and true-time delay devices. Problems such as grating lobes, beam squint, quantization errors, and scan blindness are presented. Antenna systems (transmit/receive) with active amplifiers are introduced. Finally, measurement techniques commonly used in anechoic chambers are outlined. The textbook, Antenna Theory, Analysis & Design, is included as well as a comprehensive set of course notes. 

What You Will Learn: 

• Basic antenna concepts that pertain to all antennas and antenna arrays. 

• The appropriate antenna for your application. 

• Factors that affect antenna array designs and antenna systems. 

• Measurement techniques commonly used in anechoic chambers. 

CERTIFIED SYSTEMS ENGINEERING PROFESSIONAL (CSEP) PREPARATION COURSE 

This two-day course walks through the Certified Systems Engineering Professional (CSEP) requirements and the International Council on Systems Engineering (INCOSE) Handbook to cover all topics that might be on the CSEP exam. Interactive work, study plans, and sample examination questions help you to prepare effectively for the exam. Participants leave the course with solid knowledge, a hard copy of the INCOSE Handbook, study plans, and a sample examination. 

The INCOSE CSEP rating is a useful and coveted milestone in the career of a systems engineer, demonstrating knowledge, education and experience that is of high value to systems organizations. The certification requires passing an extensive examination based on the INCOSE Systems Engineering Handbook v3.2. This course provides you with the detailed knowledge and practice that you need to pass the CSEP examination. 

See CSEP Slide Samples or see a sample of the CSEP Preparation Course on YouTube 

GPS TECHNOLOGY COURSE 

Nearly every military vehicle and every satellite that flies into space uses the GPS to fix its position. In this popular four-day short course, GPS expert Tom Logsdon will describe in detail how those precise radionavigation systems work and review the many practical benefits they provide to military and civilian users in space and around the globe. 

Each student will receive a new personal GPS Navigator with a multi-channel capability. Through practical demonstration you will learn how the receiver works, how to operate it in various situations, and how to interpret the positioning solutions it provides. 

See GPS Technology Slide Samples or see a sample of the GPS Technology Course on YouTube. 

PRACTICAL STATISTICAL SIGNAL PROCESSING – USING MATLAB 

This four day course covers signal processing systems for radar, sonar, communications, speech, imaging and other applications based on state-of-the-art computer algorithms. These algorithms include important tasks such as data simulation, parameter estimation, filtering, interpolation, detection, spectral analysis, beamforming, classification, and tracking. Until now these algorithms could only be learned by reading the latest technical journals. This course will take the mystery out of these designs by introducing the algorithms with a minimum of mathematics and illustrating the key ideas via numerous examples using MATLAB. 

Designed for engineers, scientists, and other professionals who wish to study the practice of statistical signal processing without the headaches, this course will make extensive use of hands-on MATLAB implementations and demonstrations. Attendees will receive a suite of software source code and are encouraged to bring their own laptops to follow along with the demonstrations. 

Each participant will receive two books, Fundamentals of Statistical Signal Processing: Volumes I and II by instructor Dr. Kay. A complete set of notes and a suite of MATLAB m-files will be distributed in source format for direct use or modification by the user. 

Course Outline, Samplers, and Notes 

Determine for yourself the value of these or our other courses before you sign up. See our samples (See Slide Samples) on some of our courses. 

Or check out the new ATI channel on YouTube. 

After attending the course you will receive a full set of detailed notes from the class for future reference, as well as a certificate of completion. Please visit our website for more valuable information. 

About ATI and the Instructors 

Our mission here at the ATI is to provide expert training and the highest quality professional development in space, communications, defense, sonar, radar, and signal processing. We are not a one-size-fits-all educational facility. Our short classes include both introductory and advanced courses. 

ATI’s instructors are world-class experts who are the best in the business. They are carefully selected for their ability to clearly explain advanced technology. 

Times, Dates, and Locations 

For the times, dates and locations of all of our short courses, please access the links below. 

Sincerely, 

The ATI Courses Team 

P.S. Call today for registration at 410-956-8805 or 888-501-2100 or access our website at www.ATIcourses.com. For general questions please email us at ATI@ATIcourses.com. 

 

‘VIRGINIA’-CLASS SUBMARINE PROGRAM SAILS INTO FULL RATE PRODUCTION

The USN’s ‘Virginia’-class submarine program recently achieved ‘Milestone III’ and full rate production approval with the signing of an acquisition decision memorandum by the under secretary of Defense for Acquisition, Technology and Logistics. The achievement of Milestone III coincides with the program transitioning to a schedule involving the construction of two submarines per year, starting in fiscal year 2011. Construction of the first two Block III vessels began in March 2009 (SSN-784) and March 2010 (SSN-785). The seventh ship of the class, the ‘Missouri’ (SSN-780) was commissioned on 31 July 2010. There are five additional ‘Virginia’-class submarines under construction, and six more under contract.

New Course Explores Science of Noise Impacting Marine Mammals

The Beluga whale is one of over 120 species of marine mammals impacted by ocean noise.
The Beluga whale is one of over 120 species of marine mammals impacted by ocean noise.

Applied Technology Institute Introduces New Course:

Underwater Acoustics for Biologists and Conservation Managers

New course explores the science of noise that impacts marine mammals and other ocean life

(ANNAPOLIS. Md, May 17, 2010) Technical professional development training company, Applied Technology Institute (ATI), is introducing a new course, Underwater Acoustics for Biologists and Conservation Managers. The three-day course is designed for biologists and conservation managers who wish to enhance their understanding of the underlying principles behind underwater and engineering acoustics. Understanding this science is critical to the success of marine research facilities that are responsible for evaluating the impact of anthropogenic noise on marine life.

Target audiences will include marine research facilities like the Office of Naval Research (ONR) and the National Oceanic and Atmospheric Administration (NOAA). Currently the NOAA is overseeing the BP oil spill clean up that occurred in the Gulf of Mexico last week. The NOAA umbrella organization includes divisions responsible not only for environmental clean up emergencies, but also for assessing biological harm to marine life through the NOAA Fisheries Services division.

Take this course to make better assessments of the impact of sound on marine life

Specific course outline points include learning about key characteristics of man-made sound sources, evaluating sound fields from impulsive coherent and continuous sources, discussing how system characteristics are measured and calibrated, as well as what animal characteristics are important for assessing both impact and requirements for monitoring and mitigation. By the conclusion of the course attendees will have obtained the knowledge to perform basic assessments of the impact of anthropogenic sources on marine life in specific ocean environments, and to understand the uncertainties in their assessments.

Together, ATI Instructors, Dr. William T. Ellison and Dr. Orest Diachok, bring more than eighty years of expertise in marine acoustics and biology to share with attendees.

The full course outline can be viewed on ATI’s website at:

Course Outline: Underwater Acoustics Biologists Conservation Managers

Sample materials are available on ATI’s website for prospective attendees interested in seeing the value of the course before registering. Click on the following:

Sample Materials: Underwater Acoustics Biologists Conservation Managers

Date, Time and Location:

The first class will be offered from 8:30 am to 4:30 pm on June 15-17, 2010 in Silver Spring, MD (just outside of Washington, DC). Space is limited. Call today to reserve a seat.

Sincerely,

The ATI Courses Team

P.S. For registration: Call today at 410-956-8805 or 888-501-2100 or go online now at ATIcourses.com

About Us

The Applied Technology Institute (ATI) specializes in professional development seminars in the technical areas of Space, Communications, Defense, Sonar, Radar, and Signal Processing. For over twenty-five years, ATI has presented leading-edge technical training to defense and NASA facilities, as well as DoD and aerospace contractors. ATI courses provide a clear understanding of the fundamental principles and a working knowledge of current technology and applications. ATI has the unique capability to schedule and deliver courses in a matter of weeks. They offer customized on-site training at your facility anywhere in the United States, as well as internationally and over 100 public courses annually in dozens of locations. World-class design experts lead courses. To register or for an on-site quote, call (888) 501-2100, or visit them on the web at www.ATIcourses.com


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Comments From Environmental Scientist On Reducing Low-Frequency Home Noise and Vibration

Well, we seemed to have hit a nerve with our series of posts on Reducing Low-Frequency Home Noise and Vibration:

The comment below came from a wonderful gentleman willing to help a fellow human being.

I am an environmental scientist, and have been involved in the wind energy industry where this is also an issue. The problem is uncommon, with less than 1% of the general population able to detect LFS (Low Freq sound – less than 20 Hz) dominated by people over the age of 50, and two thirds are women. So you are not imagining the issue, but keep in mind that it is unlikely that it is your ears that are detecting the sound, and that LFS behaves very differently than audible sound does.

I find your solution to be very innovative, and supported by some excellent work by a retired Univeristy Prof (Dr Barnes) in London, England. He obtained a microphone and laptop datalogger and wandered the city obtaining background readings. One of his more interesting observations was that background LFS declined after heavy trucks passed when near high traffic roads. This suggests that LFS can be neutralized by other LFS sound.

I am no sound expert, but this is the only solution I have ever read about. It is basically the “white noise” approach used for audible sound, but in that case the goal is to increase the individuals toleration for the sound (which is how white noise works, by raising our detection threshold) but rather to distrupt and decrease the level of LFS inside your house, by increasing the levels of LFS generated inside the house.

I know this sounds a bit out there, but read a few of the other accounts given on this page, for example the one where the hum returned after a new water heater was installed. The owner blamed the new water heater as the source, but it may very well have been that the old heater was “noisy” enough to have created the interference with the LFS. Getting the new heater to run better would of course just make the problem worse.

So I put this idea out there. If you can generate a background inaudible “sound” of less than 20 Hz inside your house, using the technique described above, and play it over and over, it could disrupt the LFS being generated by the house. This could require a specialized “woofer” type of a speaker.
If anyone tries this, I would be very interested in the result.

Good Luck
D

“Green” Peace and Quiet: new noise source (the light rail train) in Seattle

Light Rail has arrived in Seattle. The first link, a 14-mile electric railway system, opened in July 2009, making access from South Seattle to the downtown core, easier and more efficient. The ability of a light rail system to run along streets and share space with road traffic makes it an ideal choice for an urban setting. Seattle’s new light rail operates on embedded tracks at street level, along elevated structures and through tunnels. This study focused on the street level segment and the potential increase in noise levels for residents along the alignment.

In order to accommodate the light rail, an arterial through Seattle’s Rainier Valley neighborhood was widened to allow the trains to travel down the center of the roadway. Not only did this introduce a new noise source (the light rail train) into the community, it also slightly increased existing traffic noise as the widening of the street relocated traffic nearer to the homes. Figure 1 shows the configuration of rail and traffic and the proximity to residences.

Figure 1. The light rail travels down the center of the road

Studies were conducted to predict the level of increased noise for homes along the alignment. The metric used to define the light rail noise was the Day-Night Level (Ldn). This metric is based upon a 24-hour average of sound with a penalty added to any sounds occurring between the hours of 10:00 PM and 7:00 AM. The penalty is intended to reflect a higher sensitivity to noise during typical sleeping hours. The traffic noise metric was based upon an hourly Equivalent Level (Leq), which is the average sound in a one-hour period. The loudest hour is used to assess impact.

The initial program included 137 residences, with predicted exterior sound levels due to the project, that were high enough to be considered “impacted”. Sound Transit, the local Transit Authority, received a grant from the Federal Transit Administration (FTA) to launch a Residential Sound Insulation Program (RSIP), designed to reduce transportation noise intrusion into homes. Each home received an acoustical audit to measure the level of sound insulation provided by the existing construction. Figures 2 and 3 demonstrate two approaches to measuring the sound insulation properties of window elements.


Masurement approach #1


Masurement approach #2

Read more here

More Information On Reducing Low-Frequency Home Noise and Vibration –

We received a question from a consumer regarding low-frequency home and vibration. After a response from expert staff of Acoustics and Noise instructors and a few additional posts on this general topic of interest, the response below came from the original consumer.

Dear Sir,

Here is my reply. You asked for it, and it is lengthy. I am so grateful that you all are taking your time to give me your suggestions. I think a probable low frequency noise source, in addition to the trains, and obvious manufacturers’ noises, could be an asphalt batch plant that is located just behind our neighborhood. I drove by and listened and it is quite noisy with its clattering conveyer belts, giant blower, and the huge rotating mixing bin. I doubt we could have any influence on quieting such an operation. When we moved into our present house this plant was hidden by trees. Now that the leaves are gone, it is easily seen. Let the renter beware!

We have tried all the things that were suggested in your e-mail. White noise machines and fans just added noise to the home and was not the solution I needed. The best brand of ear plugs worked well, but are kind of dangerous when you need to listen to what is going on in the house at night….like when someone might be sick and need help. ( mothers can appreciate this reason), or a tornado siren, etc. My husband must sleep and so I have the “night watch”. .The Bose headphones (thanks Grandma) did not do a thing for the low frequency, but one of my sons is enjoying them tremendously now for listening to music. I hate that she wasted so much money on something that didn’t work. I, too, have wasted lots of money buying several bundles of Fibrex to use as “bass traps” of sorts thinking that it might help. It did not.

We did the realtor thing also. We moved from our first house recently. That house has its own story. We had moved to this town from out of state and did not know much about the area. Well, the house we bought was down the street from a gas well compressor. It was hidden in a wooded area and we did not know about it. Who would ever think that such a thing as a gas well compressor would be in a neighborhood…..only in Texas. The days we viewed the house happened to be some of the few days a year that the compressor was down for repairs or maintenance. On closing day when I walked up the stairs to turn the key in the door, I said to my self, “What is that noise.” After searching the neighborhood, we discovered the culprit to be a very old noisy natural gas driven compressor on a gas well. I fought that oil company for a long time and only was successful getting them to put up a wooden fence that did absolutely no good. Oil companies are King around here. They always expressed to me that they were compliant. They were, but this city has wimpy standards and codes that do not measure low frequency. We had spent lots of time, sweat, tears and money fixing up “this old house” and we did not want to move. We had redone the wooden floors ourselves, and I did not want to cover them up with carpet, even though that might have helped with the sound. We couldn’t afford to change out the old windows that were huge and had just been refurbished by me. Our home was built in an L shape facing the compressor. This was perfect for capturing the “waves”. They came right in through our large glass windows. In addition to that, there were metal awnings over each window acting like ears to reflect the sound in through the single pane windows. (I had refurbished those as well) The neighborhood was refreshingly quiet on the few days that “The Beast” was off for one reason or another.

After three years of torment, the for sale sign went up. We disclosed the noise ( which probably brought our home value down) to the new buyer. She was not home much of the time anyway so she was not as bothered by it. The search for a quieter place was on. We were scared to think of buying again without knowing if “the sound” would be in that area too. , “ I had gone to look at houses for sale, just to see if I could hear how the house “sounded” and just to “test” a neighborhood. We decided just to rent. Little did we know that rental homes that are large enough for our family of six and that are in our price range are extremely hard to find in our town. We ended up having to grab a house when it became available just to get a decent place to live. As it turns out, we ended up moving from one frying pan to another frying pan so to speak. We have now been living in this rental for ten months and we are still plagued with noise problems. I say we because even though the others of our household are not as sensitive to LFN as I am, they still have to live with someone (the mom) who is and whose daily life is not as efficient as it could be were I able to sufficiently rest and relax. I went with our church on a mission trip to Mexico a couple of years ago. While up in a quiet mountain village, I discovered how wonderful peace and quiet were, and I realized just how much that LFN affected me while living in our bombarded home.

Since we now rent, I can’t beef up the windows, but I have heard that double panes do not help with low frequency anyway. I’ll try to make a window plug to see if that helps. I can’t run the TV “off channel” because we need to concentrate and study at home. We are one of those homeschooling families. Also, that noise is annoying to my teenage daughter and me.

You asked about whether or not other neighbors have had the same problems as I. I can’t tell you that. We haven’t gotten to know our neighbors very well yet. There are some factors to remember when questioning the neighbors about noise problems. Many in our neighborhood are retired and wearing hearing aids. They, of course, do not have problems with the noise. Second, if they did hear the offending frequency, they would be hesitant to say so in fear that this information might be something that could “go public” and cause their home values to go down. Third, low frequency noise is most often a source of annoyance to those fifty and older (I give away my age). The younger ones in the neighborhood have not yet reached that point. On a side note, there is an old man in the neighborhood who sits out in his attached garage with the garage door up for many hours a day. He will even sit out there when it is 100 degrees outside. I am just curious if he has a problem with LFN and is trying to escape it as I am. By the way, when I am out working in my ten by twelve foot shed (made of that composite siding stuff and sitting on wooden skids) I can’t hear or feel the vibration. This makes me wonder if the noise could be possibly ground borne. The LFN does seem to be worse when it is raining…..hum….saturated soil conducts noise very well doesn’t it. If the LFN was ground borne, would ….putting down a wood or laminate flooring that had a good coating of Green Glue behind it help. Is there any conclusive way to determine if LFN is indeed coming through a concrete slab? (I know this is some of that thousands of dollars of advice coming my way.) As was suggested, I am going to try to decouple the bed from the floor. I’ll order some sheets of sorbothane for that purpose. They are supposed to work better than rubber. What kind of instrument would measure the wall or slab vibrations?

My son, who is now an engineering major (ME), once measured the sound with a microphone on his computer. Using music recording software, he measured the frequencies from 30 to 60htz or so. He had fun isolating the sound and turning it way up for all to hear and feel till we yelled at him to shut it off….ah teens. He captured it in the tile shower. So I know it is “out there” and not just “in my head”. It could be that I am one of those “hummers”. Read about them online. They can hear the Kokomo Hum, the Taos Hum, the London Hum, etc. There is even a low frequency sufferer’s society. This is your market for whoever invents a comfortable low frequency blocking head gear that can be worn at night. This wouldn’t block (as ear plugs do) the types of noise that parent’s need to hear at night.

I would be interested in any tests like the one that one of the teacher’s mentioned ….measuring the frequency outdoors and comparing it to the indoor reading. I guess I just have to rent a device that measures what I need to measure. We would like to move, but as I said previously, I would not like to buy a home without knowing that I can block the offending noise that this town seems to produce whether from trains, underground gas pipes, well drilling, or chemical and manufacturing industries, etc. If we were to rent, we could not spend lots of money to “treat” the house for LFN. My husband likes his job and would like to stay in the area if possible. Me, I’d rather move to a small mountain village in Mexico. Or until then, I’ll just sleep with a pair of sorbothane shoe insoles smashed over my ears.

I am glad you are teaching classes to train engineers in ways of mitigating noise and vibration, because ultimately these problems have a personal side and a personal face. If I have been a “textbook” case for you then so be it, and may you all become the best problem solvers in this area. If any of you have any other suggestions for me, send them my way. If you solve my problem, then my hat is (or should I say ear plugs are) off to you. Please do not share my e-mail address with the masses.

My humble thanks,

C

Bottlenose dolphins mud-ring feeding

A pod of bottlenose dolphins off the coast of Florida have developed a remarkable hunting strategy in order to catch fish. Another awesome thing about this technique is that only one female in the pod can create this ring.


From the first episode (Challenges of Life) of the new BBC series Life.

Seafloor mapping – the many uses of multi-beam sonar

Scientists on board a federal fisheries research vassal in Alaska’s Pribilof Islands are using multi-beam sonar to survey and map seafloors. According to ecologists, mapping this vital crab habitat is an important step in preserving deteriorating king crab populations.

The primary goal of current mapping pilot project is to test the usefulness of multi-beam sonar systems for finding “shell hash” (deposits of crushed crab shell believed to be important in the survival of young crabs). In the past efforts to monitor, crab populations and record vital habitats were limited to trawl and pot surveys.

Although these surveys could inform ecologist which habitats were being used as nursery grounds for immature crabs they could not provide much needed information regarding the habitat itself. Today’s current multi-beam sonar technology has the potential to drastically transform ecologist’s ability to monitor and preserve critical habitats of declining sea species. These technologies, however, do not come without a cost. According to Michelle Ridgway, the ecologist in charge of the shell hash project the systems currently being tested cost over $3,000 an hour to operate.

After the initial data is, collected Ridgway will compare the newly collected sonar imagery to seafloor samples, side scan sonar imagery, and remotely operated vehicle video that have already been collected to help interpret the acoustic backscatter images.

http://www.alaskajournal.com/stories/062609/fis_img9_001.shtml

Acoustics and Sonar Classic Books

Classic Acoustics and Sonar books for from Peninsula Publishing Los Altos Hills, California USA

Many of these texts were written by current or retired ATIcourse instructors and several of the textbooks are given out free as part of the ATI sponsored short course on the subject.

June 2009
Principles of Underwater Sound, Third edition. Robert J. Urick. The most widely used book on underwater acoustics and sonar published today. This book continues to be the standby of practicing engineers, scientists, underwater systems managers and students. Its contents lie squarely in the middle between theory at one end and practical technology at the other. Principles summarizes fundamentals, effects and phenomena of underwater sound and their application to sonar. It provides numerical, quantitative data for the solution of practical problems. 229 figures; 23 tables; 673 references. Detailed index pinpoints data and explanations instantly. Problem section with solutions.
Hardcover. 444 pages. ISBN: 9780932146625
$74.00

Mechanics of Underwater Noise. Donald Ross. Most authoritative book on fundamentals of underwater noise radiated by ships, submarines, torpedoes. Stresses physical explanations of mechanisms by which noise is generated, transmitted by structures and radiated into the sea.
Hardcover. 375 pages. ISBN: 9780932146168
$74.00

Sediment Acoustics. Robert D. Stoll. Seminal book addressing Biot Theory for the modeling of acoustic behavior of ocean sediments. Written for seismic-acousticians in the geo-exploration, engineering, oceanographic and underwater sound communities. Stoll, a respected leader in marine geoacoustics for more than forty years, added a brief preface and updated selected bibliography to this second printing of his book, first published in 1989. Sediment Acoustics provides an excellent introduction to Biot Theory, the physics underlying the model parameters, and experimentally measurable predictions of the theory. The book constitutes a major synthesis for non-specialists: the results of laboratory, in-situ and numerical modeling studies of seismic-acoustic wave propagation, reflection and attenuation in two-phase poro-visco-elastic media. Includes tutorial sections and references for new researchers in seismic modeling, quantitative seismic stratigraphy, offshore marine geotechnique, underwater acoustics and sonar, and ground-interacting aeroacoustics.
Softcover. 172 pages. ISBN: 9780932146144
$77.00

Underwater Electroacoustic Transducers. Dennis Stansfield. This reprint is a practical handbook for users and designers of underwater transducers. It has been an authoritative text in the field since first published by the Bath University Press in 1991. Design methods are illustrated by concentrating on the design of piezoelectric transducers in the 2 – 20 kHz range, most commonly used in sonar systems. Designs for frequencies below this range are also discussed. Treatment is down-to-earth and avoids complex mathematics. Topics include the role of the transducer as an element of the complete system; wide bandwidth, high power transmitter applications; wide band hydrophones; characteristics of piezoelectric and magnetostrictive materials; and transducer testing. For the user, the wide range of topics and practical approach of the book help him to identify the most important features of the requirement and assist him in drawing up realistic specifications. For the designer, the book describes the necessary theoretical and practical aspects involved in developing a transducer to most effectively suit the application and it discusses the main features of the various types of designs.
Softcover. 429 pages. ISBN: 9780932146724
$73.00

Introduction to the Theory and Design of Sonar Transducers. Oscar Bryan Wilson. Written in 1985 as a text at the Naval Postgraduate School, this book provides a complete treatment of the fundamentals of transducer theory and design using equivalent circuit techniques. Subjects addressed: introductory baseline and definitions, equivalent circuits, properties of materials: piezoelectric and magnetorestrictive, hydrophone design and transducer arrays.
Hardcover. 202 pages. ISBN: 9780932146229
$69.00

Underwater Electroacoustic Measurements. Robert J. Bobber. Theory and practice of measuring electroacoustic parameters such as response, sensitivity, directivity, impedance, efficiency, linearity and noise limits of transducers used in sonars.
Hardcover. 341 pages. ISBN: 9780932146199
$61.00.

Matched Field Processing for Underwater Acoustics. Alexandra Tolstoy. Published by the World Scientific Publishing Company in 1993. The author was with the Naval Research Laboratory. Matched Field Processing is the process of cross-correlation of a measured field with a modeled, predicted or replica field to determine a set of input parameters that yield the highest correlation. Typically, input parameters in to a selected sound propagation model would include candidate range, bearing and depth of a source relative to the receiving array. The sound propagation model might be defined by environmental data such as sound speed profiles, bottom and surface conditions, tides, and composition of the water. The matched field processing (MFP) would be employed to determine the location of the source – the exact relative range, bearing and depth of the source. This book is for scientists and engineers who are familiarizing themselves with MFP and those in need of detailed information about the process. The first two chapters address a brief history of MFP and discuss other types of processors used in underwater acoustics. The third chapter discusses where errors in MFP solutions occur due to errors in the propagation model. Chapter 4 gives the reader a familiarity of how linear and minimum variance processors perform under a wide range of conditions. And the last chapter addresses broadband processing, source movement, and multiple sources.
Hardcover. 228 pages. ISBN: 9789810210595
$69.00

Space-Time Information Processing. Charles Loda and A. Winder. Classic reference for signal processing and data analysis for acoustic and sonar engineering. Features Fourier transforms, statistical analyses, spectra and correlation. Valuable chapters address spatially and temporally limited functions, optimal filtering procedures, and interpretation of results.
Hardcover. 192 pages. ISBN: 9780932146045
$49.00

Transducers and Arrays for Underwater Sound. Charles H. Sherman and John Butler. This book is published by Springer, released in 2007, and sold by Peninsula Publishing. This is the most recent and complete book on the theory and design of underwater transducers in print today. Sponsored by the Office of Naval Research of the U. S. Navy. This book addresses the theory, development and design of electroacoustic transducers for underwater applications. It is more comprehensive than any existing book in this field. It includes the basics of the six major types of electroacoustic transducers and shows why piezoelectric ceramic transducers are the most suitable for underwater sound. It presents the basic acoustic concepts and models needed in transducer and transducer array development, and discusses most currently used transducer designs. It analyzes nonlinear effects and describes methods of transducer evaluation and measurement. The extensive Appendix and numerous diagrams provide an up to date source for use by students and practicing engineers and scientists.
Hardcover. 630 pages. ISBN: 9780387329406
$123.00

Underwater Acoustic System Analysis, Second Edition. William S. Burdic. Provides a comprehensive exploration of underwater acoustics, acoustic signal generation, and acoustic signal processing for systems analysts, systems engineers and sonar engineers. This book is a reprint of the second edition published in 1991 and is still a classic text in the field. Updated and expanded in 1991, this edition contains all the valuable information it its earlier text plus a detailed discussion of adaptive processing as applied to spatial filtering. You will also find review sections on Fourier analysis, correlation, random processes and hypothesis testing. Highlights include: generation and propagation of compressional acoustic waves in the ocean; narrow band signatures of surface ships caused by cavitating propeller blades and diesel engine firing; optimization of signal-to-noise ratio and spatial resolution in the presence of multiple signals; ambient noise in the ocean; and examples of system performance.
Softcover. 489 pages. ISBN: 9780932146632
$87.00

Sonar Engineering Handbook. Harrison T. Loeser. Fundamentals and
engineering formulas dealing with sonar, signal processing, sound transmission, noise generation, vibration control and elastomers. Each formula is briefly explained in an associated paragraph with references provided for detailed follow up.
Softcover. 216 pages. ISBN: 9780932146595
$55.00

Ambient Noise in the Sea. Robert J. Urick. Examines significant aspects of ambient noise beneath sea’s surface: definition; measurement; sources; variation. Essential for work in sonar systems.
Hardcover. 205 pages. ISBN: 9780932146137
$48.00

Sound Propagation in the Sea. Robert J. Urick. Overviews underwater sound propagation, multipath, deep sound channel, sea surface reflections scattering, attenuation, absorption, modeling.
Hardcover. 225 pages. ISBN: 9780932146083
$53.00

Physics of Sound in the Sea. Milestone work on undersea sound propagation resulting from the World War II studies. Discusses transmission loss, target strength and echoes from subs/surface ships, sound transmission through wakes, etc.
Hardcover. 577 pages. ISBN: 9780932146244
$59.00

Side Scan Sonar Record Interpretation. Charles Mazel. Training manual produced by Klein Associates, Inc., manufacturer of side scan sonars. Applies to interpretation of all commercial side scan sonars. The 144 figures and photographs of actual sonar records depict mine and ship targets, shadows, clutter, noise, wakes and dolphins.
Softcover. 146 pages. ISBN: 9780932146502
$69.00

Noise Reduction. Edited by Leo L. Beranek. Classic book of fundamentals of noise control and noise reduction for the general engineer. Elementary beginnings leading to the advanced aspects of noise reduction for offices, residences, auditoriums and transportation vehicles. Case histories and abundant references.
Hardcover. 776 pages. ISBN: 9780932146588
$47.00

Collected Papers on Acoustics. Wallace Clement Sabine, the Father of Architectural Acoustics. Acoustic problems in theater, auditorium, church, classrooms and their solutions. Magnificent sketches and photos. This unabridged volume forms the foundation of modern architectural acoustics.
Hardcover. 304 pages. ISBN: 9780932146601
$57.00

Signal Detection and Recognition by Human Observers. Edited by John A. Swets in 1964, this book was the first to bring together into one volume a broad discussion coverage of modern signal detection theory applications to human performance, specifically in auditory and visual sensory tasks. Applications address problems in psychology including the integration of sensory information, signal uncertainty, auditory frequency analysis, speech communication, vigilance and recognition memory. Bibliography updated to 1988.
Hardcover. 734 pages. ISBN: 9780932146212
$64.00

Signal Detection Theory and Psychophysics. David Green and John Swets. Summarizes the application of signal detection theory to the analysis and measurement of the human observer’s sensory system. Outlines the theory of statistical decision making and its application to a variety of common psychophysical activities. Applies signal detection theory to problems in a sensory psychology.
Hardcover. 521 pages. ISBN: 9780932146236
$78.00

Applied Acoustics. G. Porges. Develops the basic theory of sound from first principles and applies the theory to obtain practical formula for the transmission and absorption of sound, sound levels in closed spaces and the radiation of sound from common noise sources. In keeping with the practical orientation of the book, the mathematics used is relatively elementary.
Hardcover. 190 pages. ISBN: 9780932146182
$41.00

The Sabines at Riverbank. John Kopec. Chronicles the people and research involved in the birth and first decades of the science of architectural acoustics. Here is the history of the first family of architectural acoustics, the Sabines, and the Riverbank Acoustical Laboratories, the world’s first independent laboratory for measuring the acoustical properties of architectural materials. The story begins in the early 1900s with Wallace Clement Sabine, a Harvard professor, who led the practice of acoustics toward a quantitative science with great insight, industry and integrity. He was followed by two other giants in the field of architectural acoustics: Paul Earls Sabine, a cousin, and his son, Hale Johnson Sabine, all Harvard graduates. No one other than John Kopec with his historical perspective and inside knowledge of the lab could have authored this extraordinary history.
Hardcover. 230 pages. ISBN: 9780932146618
$37.00

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