What is an Acoustic Transducer?

From Wisegeek.com “What is an Acoustic Transducer?” (16 January 2013)

An acoustic transducer is an electrical device that coverts sound wave vibrations into mechanical or electrical energy. They have various practical applications, including sound recording and sound playback. A specialized model, called an ultrasonic acoustic transducer, can be used to measure distance to, as well as the mass of, an object.

Common types of acoustic transducers used in sound recording include microphones, earphones, and guitar pickups. These create electrical energy when moving parts inside the transducer, such as electrical plates or ribbons, are exposed to sound vibrations. The electrical energy produced inside the transducer is sent first to an amplifier.

The amplifier then sends this energy to its final destination, usually a loudspeaker or recording device. The loudspeaker reproduces the sound at a level that the human ear can hear. A recording device will retain the electrical signal information. The recorder will send the stored signal to a loudspeaker during playback.

An ultrasonic acoustic transducer can be used to measure distance or the mass of an object. The most common type is the piezoelectric acoustic transducer. These include a piezoelectric ceramic element that creates and distributes ultrasonic sound waves.

Sound waves travel to an object from a piezoelectric transducer through material called a couplant. The couplant is usually water. Sound waves bounce off the object and return to the transducer in the form of an echo. The time it takes for these echoes to return to the transducer is used to calculate the distance to the object.

Underwater sound navigation and ranging (SONAR) is a common use of an ultrasonic acoustic transducer. SONAR uses directional beams of sound waves. This enables the SONAR operator to determine the direction and distance to an object.

SONAR systems can be active or passive. An active system sends out sound waves and listens for echoes. A passive system listens for noises made by ships, fish, and landmasses.

An electromagnetic acoustic transducer (EMAT) is another form of ultrasonic transducer. Instead of a ceramic element, an electro magnet is the main component of an EMAT. This is a type of non-contact, or non-destructive transducer. Unlike piezoelectric transducers, EMATs do not need a couplant to carry sound waves. Instead, two electromagnetic fields are generated to disburse ultrasonic waves.

EMATs can easily be used almost anywhere since no liquid is needed. For example, EMATs can be used to check for flaws in underground pipes. A downside to EMATs, compared to piezoelectric transducers, is that EMATs create weaker sound fields.

 

Diverse Power Leverages Exalt Backhaul for Large-Scale UHF Radio Network

With very little information on the internet about walkie talkie’s, it is very rare when we get a chance to re post, with permission, an article from this industry.

 

Exalt Communications, Inc., the leading innovator of next-generation wireless connectivity systems for private networks and Internet infrastructures, today announced that Diverse Power, an electric membership cooperative based in La Grange, GA has deployed Exalt ExploreAir microwave backhaul systems to link traffic from its TETRA UHF radio network back to its fiber core.

With 36,000 customers throughout counties in Georgia and Alabama, Diverse Power’s far-flung operations in this rural area require highly reliable radio communications among its maintenance personnel. Working with Exalt partner Dean’s Commercial Two-Way of Cataula, GA, Diverse Power deployed a TETRA UHF radio system for its workers and selected Exalt ExploreAir microwave backhaul systems to carry traffic among sites in Manchester, Mulberry Grove, and Red Oak, GA.

“We wanted a first-class system all the way with our radio network, and Dean’s Two Way recommended Exalt for its outstanding performance and reasonable price,” said Randy Shepard, senior vice president of Diverse Power. “Exalt gives us a fiber-speed backhaul infrastructure that we can rely on in all weather conditions, even during the recent ice storms.”

Diverse Power deployed Exalt ExploreAir systems in all-outdoor configurations on links between Mulberry Grove and Manchester, and between Red Oak and Manchester. The systems carry 100 megabits per-second of Ethernet traffic. While the microwave systems backhaul voice radio traffic today, Diverse Power is looking ahead to carrying SCADA traffic over the links in the future.

“Fiber and microwave are the only technologies that can reliably backhaul traffic, and Exalt microwave offers customers distinct advantages when expanding a network over a broad geographical area,” said Amir Zoufonoun, CEO of Exalt. “Our systems are scalable, providing customers like Diverse Power the capacity they need to optimize energy delivery, increase productivity, enable two-way information exchange with customers for greater control over their electricity costs, and easily add future service offerings.”

About Exalt Communications

Exalt Communications, Inc. is a forerunner in the global Internet revolution, delivering high-value wireless systems that transform the economics of connectivity. Exalt wireless systems extend or complement network fiber and replace now-outdated copper, enabling customers to accelerate time-to-market, optimize network performance, and reduce network infrastructure costs. Today, over 2,000 global customers, from the world’s largest mobile operators to independent service providers, government agencies, and multinational enterprises depend on Exalt systems as they move their applications to the Cloud, enable mobility, and connect the unconnected.

Read more at http://www.broadwayworld.com/bwwgeeks/article/Diverse-Power-Leverages-Exalt-Backhaul-for-Large-Scale-UHF-Radio-Network-20140402#VrUcmLhd4WjO3IKs.99

What is an Acoustic Transducer?

From Wisegeek.com “What is an Acoustic Transducer?” (16 January 2013)

An acoustic transducer is an electrical device that coverts sound wave vibrations into mechanical or electrical energy. They have various practical applications, including sound recording and sound playback. A specialized model, called an ultrasonic acoustic transducer, can be used to measure distance to, as well as the mass of, an object.

Common types of acoustic transducers used in sound recording include microphones, earphones, and guitar pickups. These create electrical energy when moving parts inside the transducer, such as electrical plates or ribbons, are exposed to sound vibrations. The electrical energy produced inside the transducer is sent first to an amplifier.

The amplifier then sends this energy to its final destination, usually a loudspeaker or recording device. The loudspeaker reproduces the sound at a level that the human ear can hear. A recording device will retain the electrical signal information. The recorder will send the stored signal to a loudspeaker during playback.

An ultrasonic acoustic transducer can be used to measure distance or the mass of an object. The most common type is the piezoelectric acoustic transducer. These include a piezoelectric ceramic element that creates and distributes ultrasonic sound waves.

Sound waves travel to an object from a piezoelectric transducer through material called a couplant. The couplant is usually water. Sound waves bounce off the object and return to the transducer in the form of an echo. The time it takes for these echoes to return to the transducer is used to calculate the distance to the object.

Underwater sound navigation and ranging (SONAR) is a common use of an ultrasonic acoustic transducer. SONAR uses directional beams of sound waves. This enables the SONAR operator to determine the direction and distance to an object.

SONAR systems can be active or passive. An active system sends out sound waves and listens for echoes. A passive system listens for noises made by ships, fish, and landmasses.

An electromagnetic acoustic transducer (EMAT) is another form of ultrasonic transducer. Instead of a ceramic element, an electro magnet is the main component of an EMAT. This is a type of non-contact, or non-destructive transducer. Unlike piezoelectric transducers, EMATs do not need a couplant to carry sound waves. Instead, two electromagnetic fields are generated to disburse ultrasonic waves.

EMATs can easily be used almost anywhere since no liquid is needed. For example, EMATs can be used to check for flaws in underground pipes. A downside to EMATs, compared to piezoelectric transducers, is that EMATs create weaker sound fields.

 

What Is Covert Surveillance?

The world is full of really cool, well written content pieces. Whenever you find one which catches your eye, you have to repost it, well i do! so with permission of the original writer i’ve re-posted this so that you can get pleasure from

Covert surveillance occurs when someone or something is being observed without knowledge. People who are under surveillance are most often under suspicion. Locations and buildings are primarily observed because of suspicious activity or to obtain information about a suspect.

covert surveillance Covert surveillance is generally performed by government agencies, private investigators or business owners. Intelligence organizations such as the Central Intelligence Agency (CIA) of the United States and the United Kingdom’s Secret Intelligence Service, also called MI6, participate in surveillance to obtain information for national security interests such as counter terrorism. Law enforcement agencies such as the United States’ Federal Bureau of Investigation (FBI) or the International Criminal Police Organization (INTERPOL) also perform surveillance. They concentrate on observing suspected criminals.

Private investigators perform covert surveillance for a variety of reasons. Husbands and wives hire private investigators to prove or disprove suspected infidelity. Businesses hire private investigators to observe employees who are suspected of fraudulent activities or former employees that may be breaking confidentiality agreements. Insurance companies are notorious for using private investigators to put claimants under surveillance to ensure they are not submitting a fraudulent claim.

Many business owners participate in covert surveillance of their employees and customers. Observing employees while they are working gives business owners valuable information, such as employee production and employee theft. Covertly observing customers can aid in marketing and research efforts and most importantly account for loss due to theft in retail businesses. Retail businesses can also use information obtained through covert surveillance to prosecute shoplifters.

A surveillance operation may be carried out in a number of ways. Agency employees and private investigators may choose to observe a subject without the aid of sophisticated technology, using things such as binoculars and cameras. However, in an age of modern technological conveniences, it is safer, cheaper and more convenient to use surveillance equipment.

Closed circuit television systems (CCTV) are one of the most popular ways to carry out covert surveillance. Cameras come in all sizes and can be placed inconspicuously almost anywhere. In order to obtain audio, wire taps can be placed on phones or audio surveillance equipment may be hidden in a suspect’s office, home or vehicle. Other ways to perform covert surveillance include aerial surveillance and the use of global positioning systems (GPS). A GPS placed on a person or moving vehicle can be tracked to monitor movement to specific locations. Similarly, aerial surveillance carried out by national governments can track objects on the ground.

 

I Work At A College And I’m Looking To Revamp Our Long-Distance Communications, Any Ideas?

Your best bet, be it for general use in academic studies, health and safety concerns or simply security, would be to employ a digital two-way radio system, something like the Motorola SL4000. I’m specifically suggesting Motorola because they handle jobs like this all the time, several of which are detailed on their website.

In fact, the Motorola website details a case almost exactly like yours, where this technology was employed to great effect.

According to the site, the Cincinnati State Technical and Community College (CSTCC) was in a situation just like the one you outlined in your email. Here’s the basic issue…

“CSTCC is comprised of three campuses and over 1.3 million square feet. Until recently, the college used an all-analog system, components of which were 15 years old.  According to Raymond Mirizzi, Director of Facilities atCSTCC, “We needed to upgrade our whole communications system,” and it was vital that the entire campus be covered with a radio solution that would support very clear, consistent and secure communications”.

How a two-way radio network helped the situation is also detailed.

“The three-part campus needed a supervisory channel that would provide the flexibility for critical security officers and related personnel to communicate during times of crisis. Of course, because such emergencies can arise at any time, it was also critically important that the migration from analog to digital proceed smoothly and quickly because even brief downtime could put the campus at risk”.

There are lots of companies other than Motorola, of course, but there’s no denying that they are giants in their field, with a long history of customer satisfaction. They are something like The ‘A’ Team in that respect. Still, if your budget doesn’t quite allow for bells and whistles, there are a number of quality independent firms that could do a very good job at a slightly more reasonable rate.

The reality here is that bargains are the exception, not the rule. That’s why we’re always so happy when we get one. By far your best bet is to get an expert to design and implement your faculty’s new communications method. It needn’t be the biggest company, but you want to spend a good amount on communications, as they really do save lives. 

I Work At A College And I’m Looking To Revamp Our Long-Distance Communications, Any Ideas?

Your best bet, be it for general use in academic studies, health and safety concerns or simply security, would be to employ a digital two-way radio system, something like the Motorola SL4000. I’m specifically suggesting Motorola because they handle jobs like this all the time, several of which are detailed on their website.

In fact, the Motorola website details a case almost exactly like yours, where this technology was employed to great effect.

According to the site, the Cincinnati State Technical and Community College (CSTCC) was in a situation just like the one you outlined in your email. Here’s the basic issue…

“CSTCC is comprised of three campuses and over 1.3 million square feet. Until recently, the college used an all-analog system, components of which were 15 years old.  According to Raymond Mirizzi, Director of Facilities atCSTCC, “We needed to upgrade our whole communications system,” and it was vital that the entire campus be covered with a radio solution that would support very clear, consistent and secure communications”.

How a two-way radio network helped the situation is also detailed.

“The three-part campus needed a supervisory channel that would provide the flexibility for critical security officers and related personnel to communicate during times of crisis. Of course, because such emergencies can arise at any time, it was also critically important that the migration from analog to digital proceed smoothly and quickly because even brief downtime could put the campus at risk”.

There are lots of companies other than Motorola, of course, but there’s no denying that they are giants in their field, with a long history of customer satisfaction. They are something like The ‘A’ Team in that respect. Still, if your budget doesn’t quite allow for bells and whistles, there are a number of quality independent firms that could do a very good job at a slightly more reasonable rate.

The reality here is that bargains are the exception, not the rule. That’s why we’re always so happy when we get one. By far your best bet is to get an expert to design and implement your faculty’s new communications method. It needn’t be the biggest company, but you want to spend a good amount on communications, as they really do save lives. 

What Is Kevlar Used For?

You mean besides reinforcing the tyres on the Batmobile? (True Bat-Fact – look it up).

For those not in the know, Kevlar (or Poly-paraphenylene terephthalamide, to give the material its scientific name) is a very tough and durable man-made fibre. It was first developed in 1965 by Polish-American scientist Stephanie Kwolek and has been commercially used around the world since the early 1970’s. Today, Kevlar is available in several grades, which are used for different tasks and exhibit greater, or lesser, tensile strength as well as flexibility and tenacity.

Since its introduction in 1971, Kevlar has been used for body armour (i.e. bullet proof vests), army helmets/protective gear, car and bicycle tyres (I once had a set, actually), protective clothing, paraglider suspension lines, shoe tread, headphones, musical instruments (strings and drumskins), fire resistant clothing, kitchenware (for its non-stick properties), cables and ropes, brake pads in cars, smartphone casing and even wind-turbines.

According to DuPont, Kevlar’s parent company,

“It’s about resilience, strength, saving the day, and helping keep people safe from harm —DuPont™ Kevlar®. DuPont™ Kevlar® aramid fiber is used to make a variety of clothing, accessories, and equipment safe and cut resistant. It’s lightweight and extraordinarily strong, with five times the strength of steel on an equal-weight basis. Best known for its use in ballistic and stab-resistant body armor, Kevlar® brand aramid fiber has shown its own heroism in helping to save the lives of thousands of people around the world. And since its invention over 40 years ago, things have only gotten better. DuPont™ Kevlar® continues to take on new challenges, with our scientists continuously innovating and working on a range of new opportunities through collaborations with communities, industrial manufacturers, and governments. Together we’re bringing the strength and durability of Kevlar® to so much more. The result? Kevlar® aramid fiber is now successfully used in everything from vehicles and industrial clothing to fiber optics and city roads. And we’re only getting started”.

The discovery of this wonderful material is actually quite an interesting story. Back in 1964, Kwolek’s group was searching for a way to make tyres stronger, but also a little bit lighter. Apparently, the by-products of their solutions were usually thrown away, but Kwolek saw potential in one of them, as it had formed a type of liquid crystal, something that had never been seen in their polymers before. She tested the strength of the new material and discovered that it was extremely strong. The rest, as they say, is Wikipedia.

Oh, Happy New Year, by the way! 🙂

How do I remove the wax from my hearing aid?

Asked by Colin from Leicester

Hi Colin, Before we start, can I ask if you have false teeth at all?

I know what you’re thinking, “Oh, just because I have a hearing aid, I must have dentures as well! Bloody cheek!”

Well stop. I assure you, I’m not thinking that. The reason I ask is that you will need some denture cleaning tablets for the procedure I’m sharing with you, that’s all.

Anyway, if you don’t have any tablets, go out and buy some (they are usually quite affordable, in fact, I think I saw some in the Pound Shop once).

Once you have the tablets, read this next bit (see, here I’m assuming that you DON’T have any false teeth, happy now?).

OK, first of all, you need to detach the earpiece and the tube from any electronic components.

Once you’ve done that, make a small ‘bath’ big enough to fit your hearing aid earpiece into. It is imperative to use a clean glass, in order to avoid infections (“Oh, I see, now my cups are dirty!?” he says. Maybe). Add the denture-cleaning tablet to the glass and let it effervesce (which is a lovely word that I don’t get to use nearly enough, so thank you for that).

Next, soak the earpiece and the tube in the water. DO NOT add any electrical components to the water – I’m sure you won’t, but I have to make sure that other people – stupid people, if I’m honest – don’t ruin their hearing aids and them blame me for it.

Finally, take the earpiece and/or tube and allow them to dry on a clean surface. It is best not to try and manually dry the earpiece because you’re likely to miss a bit (“Oh, I see! I can’t dry off a little bit of plastic now, is that it!?” – I imagine you saying). I say this because a wet hearing aid can damage your device and also cause ear infections.

Finally, when all is dry, simply put your hearing aid back together and start living your wax-free life.

I hope that helped (and that you didn’t mind my good-natured ribbing!)

How do I remove the wax from my hearing aid?

Asked by Colin from Leicester

Hi Colin, Before we start, can I ask if you have false teeth at all?

I know what you’re thinking, “Oh, just because I have a hearing aid, I must have dentures as well! Bloody cheek!”

Well stop. I assure you, I’m not thinking that. The reason I ask is that you will need some denture cleaning tablets for the procedure I’m sharing with you, that’s all.

Anyway, if you don’t have any tablets, go out and buy some (they are usually quite affordable, in fact, I think I saw some in the Pound Shop once).

Once you have the tablets, read this next bit (see, here I’m assuming that you DON’T have any false teeth, happy now?).

OK, first of all, you need to detach the earpiece and the tube from any electronic components.

Once you’ve done that, make a small ‘bath’ big enough to fit your hearing aid earpiece into. It is imperative to use a clean glass, in order to avoid infections (“Oh, I see, now my cups are dirty!?” he says. Maybe). Add the denture-cleaning tablet to the glass and let it effervesce (which is a lovely word that I don’t get to use nearly enough, so thank you for that).

Next, soak the earpiece and the tube in the water. DO NOT add any electrical components to the water – I’m sure you won’t, but I have to make sure that other people – stupid people, if I’m honest – don’t ruin their hearing aids and them blame me for it.

Finally, take the earpiece and/or tube and allow them to dry on a clean surface. It is best not to try and manually dry the earpiece because you’re likely to miss a bit (“Oh, I see! I can’t dry off a little bit of plastic now, is that it!?” – I imagine you saying). I say this because a wet hearing aid can damage your device and also cause ear infections.

Finally, when all is dry, simply put your hearing aid back together and start living your wax-free life.

I hope that helped (and that you didn’t mind my good-natured ribbing!)

A Review of The New Nexus 7 Tablet

In the 1994 movie ‘Star Trek: Generations’ the character of Guinan tells Captain Picard about the Nexus, a sort of temporal energy ribbon where all your hopes and dreams appear to have come true. “Its like being inside joy” she says of this ‘space ribbon’. It is a description that also fits the new Google Nexus 7, the latest update to the future-classic Android tablet. Just like Star Trek’s Nexus, this new 7-Inch masterpiece also feels like it can bring any passing whim to life…Its a little slice of space age magic.

Pathetically nerdy framing device aside, the new Nexus is truly a joy to use.

Essentially an update on the original Nexus 7 (but only inasmuch as tablet technology had advanced a lot in the last year or so), the newest member of the family Nexus has experienced a slight price increase (from £160 to £200 for a 16GB model), but that is to be expected given the updated technology available here, not to mention the rough and tumble of the decade’s economics thus far…

Frankly, it would be forgivable to expect a much larger price hike based on the strong sales of the original, but Google are smart people and they understand that the Nexus’ low price is a major selling point.

The 2013 Nexus 7 is lighter and thinner than its predecessor (the original weighed 340g, whereas the new one weighs just 290g). The new outer casing looks the part, for sure, but it’s actually the area that we found the most problems with…

For starters, the ‘improved’ screen is actually a major drawback; it is a case of form over function, of style over substance.

Essentially, the new screen has been embiggened, but to the detriment of the device itself. Due to this ‘improvement’, it is now tough to hold the Nexus without placing a digit on the touchscreen, which is problematic. It’s fine if you’re actively engaged in something, but a total pain in the you-know-where if you’re watching a video clip or navigating a menu. Unusually for Google, this comes across as poorly thought out.

The back is no longer coated with plastic, which makes it as slippery as a greased up iPhone. This will make the 2013 Nexus harder to keep hold of (and may increase its chances of sliding down in-between the sofa cushions and thereby being lost forever).

The screen, on the other hand, is beautiful. It’s as good as almost anything out there. It’s not a Retina screen, of course, but it’s easily the best you’re going to get for the asking price.

In addition, the 2013 Nexus is quicker than a whippet with a firework lodged tightly up you-know-where – and we mean that. You can put this thing to sleep (for hours, if you like) and yet, the second you boot it up again, the New Nexus is wide-awake, ready to rock and/or roll. As a matter of fact, the battery life, although not quite as good as the older Nexus, is good enough that you could probably let it sleep for days before you had to even think about charging.

Generally speaking, this is the old Nexus 7 but smaller, thinner and faster. It really is a joy to use, as well as an absolute steal at the price. Almost intuitively, this tablet knows what you want it to do and then does it.

Sure, Android OS eats about 6GB of the memory (causing immediate memory problems if you buy the 16GB version), but it really is worth it. The Nexus series are arguably the best Android models out there, with the OS and the tablet being literally made for each other, so it does make sense in the end, we suppose.

Overall, the New Nexus 7 is not without its faults. There are things we preferred about the original Nexus 7 and there are things we prefer about this one. As an upgrade, however, the 2013 Nexus 7 is still a sound investment. 

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