Wikipedia:Reference desk/Archives/Science/2013 November 14

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November 14

Type of hearing loss with anger at loud sounds

There's a type of hearing loss that is characterized by extreme sensitivity to loud sounds, which is typified by abnormal anger in the patient when subject to loud sounds. I remember it being called something like acquisition deafness; although acquisition is apparently the wrong word. Can anyone identify the name of this type of hearing loss? Thanks. μηδείς (talk) 01:08, 14 November 2013 (UTC)

(Three words I am not looking for are phonophobia, hyperacusis, and misophonia. It was a two-word term, axxxxxxxx deafness.)

Acoustic trauma? It's two words starting with "A", at least. Red Act (talk) 02:44, 14 November 2013 (UTC)

The "anger at loud sounds" bit sounds like one of the symptoms of autism. StuRat (talk) 03:39, 14 November 2013 (UTC)

No, acoustic trauma's not it. Autism isn't even close, unfortunately. It was a type of hearing loss in otherwise "normal" older people that was accompanied by extra sensitivity to loud sounds, to the point of outrage at an unexpected loud sound. It was something I hadn't heard of until I went looking for articles on hearing loss and heard of this specific type. μηδείς (talk) 04:58, 14 November 2013 (UTC)

I've never heard of that as a natural phenomenon, but I can tell you from experience that it commonly happens in older people who wear hearing aids. Looie496 (talk) 15:52, 14 November 2013 (UTC)

It sounds like you're describing loudness recruitment (see: [1], [2], [3]), which is related to/part of Sensorineural hearing loss. I couldn't find the specific term you were looking for, but the only thing I can think of would be "acquired deafness", but that's only an indicator of when, not the what. Presbycusis is age related hearing loss, it could be described as "acquired" and it can/does involve recruitment.Phoenixia1177 (talk) 07:15, 14 November 2013 (UTC)

Yes, that's it! It was loudness recruitment. Wonderful, thanks! μηδείς (talk) 16:02, 14 November 2013 (UTC)

Resolved

Ducks adopt unrelated chicks?

Hi, noticed that a particular species of duck often has hordes of ducklings following the parents around, often as many as 20-24. However checking out the species page i note the clutch size is only about 10 wood duck. Where do the extra chicks come from? I've heard of parents ducks adopting as many chicks as they can since ducklings are largely autonomous in terms of feeding and don't require any extra work while the more foreign ducklings she has the greater the chance of her own surviving a crow/seagull attack.. couldn't find anything after a few quick Google searches on the topic however. ideas? --Benjamint 01:40, 14 November 2013 (UTC)

I could think of additional reasons for adopting other ducklings:

1) Once the adopted ducklings mature, they provide mating opportunities for their own ducklings, and prevent inbreeding.

2) Since they fly in flocks, it's useful to have a larger flock, for better aerodynamic efficiency, etc. StuRat (talk) 03:37, 14 November 2013 (UTC)

Good observation, and question! First, I'll note that brood size varies wildly. Just because 10 is the average number of hatchlings doesn't mean some broods might be much larger. But, various duck species do "adopt" other ducklings which were not originally part of their brood (let's leave "unrelated" out of this, because there's a decent chance that neighboring females of of the same species are related.)

Here's a study of a few other spp., "Causes and functions of brood amalgamation in Barrow's Goldeneye and Bufflehead" [4]. From the abstract,

“ In 3 years of observations there was no significant relationship between brood size and duckling survival. I contend that brood amalgamation in Barrow's Goldeneye and in Bufflehead has not evolved as an adaptation to increase young and (or) female survival but that it is simply an accidental outcome of territorial aggressiveness. ”

--So at least one author thinks it is more of a by-product, and not an adaptive trait. However, different spp. will have different social structures, environment, migratory patterns, predators, and so on, so we can't just generalize to all fowl from a few spp.

Here's another paper looking at Eider brooding behavior [5], which says

“ Thus, the cost of adopting additional

ducklings may be small, and Eadie and Lumdsen (1985) listed three possible ways in which the risk of predation of the female's own young could be reduced through adoption. First, the addition of foreign young would dilute the recipient's brood size. Second, larger groups may more rapidly detect, and confuse, a predator. Third, mortality of the recipient's young may be reduced through the selfish herd effect (Hamilton 1971 ; Nudds 1980). In our study there was no increase or decrease in survival with brood or creche size. Thus, our data are not consistent with the dilution effect hypothesis, and we cannot reject the neutral effect hypothesis

”

(emphasis mine)--So, scientists have looked at possible benefits of brood amalgamation in at least three spp., and haven't found any strong evidence of said benefits, e.g. decrease in predation mortality. I might poke around a bit more, but anyone who's interested (and perhaps has access) can use google scholar's features to see who has cited these works, maybe someone has figured out more about this more recently, or perhaps more specifically to the Australian wood ducks that you've observed. Also, I only skimmed the articles, but both have much more info and discussion that is highly relevant. If anyone wants to read them but can't access, feel free to contact me. SemanticMantis (talk) 17:06, 14 November 2013 (UTC)

Earthling Phone Home!

Orbit size comparison of GPS, GLONASS, Galileo, BeiDou-2, and Iridium constellations, the International Space Station, the Hubble Space Telescope, and geostationary orbit (and its graveyard orbit), with the Van Allen radiation belts and the Earth to scale.

The Moon's orbit is around 9 times as large as geostationary orbit. (In the SVG file, hover over an orbit or its label to highlight it; click to load its article.)

If we disregard all possible national security and flight safety issues, can an astronaut in the ISS or any earth-orbiting spacecraft phone home using the Iridium service? (If the radio signal can penetrate the spacecraft's metal hull).

Most manned spacecrafts, except for Apollo moon rockets, are travelling below Iridium's orbits. They must have very good views of many of these satellites at any moment. Does the speed affect their use of Iridium phones?

What would happen if they use a very powerful GSM cellphone to phone home? Let's say a Russian cosmonaut wants to phone home when the ISS is over the great Russian land (if your country is too small, the ISS flies past your country in less one minute!). His beefed-up signal could be picked up by hundreds of ground stations. However, each station may only hear the signal for a very short time depending on signal strength. How does the GSM handle this situation.

Can an astronaut use his off-the-shelf GPS smart phone, tablet or wrist watch to get his approximate location over earth?

Many spacecrafts use GPS as a way of navigation. They must take altitude into consideration. However, the GPS or Glonass circuits in consumer devices probably assume that you're on the ground or maybe within civilian aviation altitudes. How do these inexpensive gadgets operate if they are 400 km above the earth? -- Toytoy (talk) 01:42, 14 November 2013 (UTC)

Some systems like the GPS receiver may not believe that it could be travelling so fast, and therefore not lock on correctly. For a telephone system the Doppler shift would be large and not acceptable to the operator. So I suspect it would not work. Graeme Bartlett (talk) 10:56, 14 November 2013 (UTC)

Consumer GPS is designed to shut down if it moves too fast and/or too high. This is to prevent garage tinkerers and unfriendly folks from building GPS-enabled intercontinental ballistic missiles. (Also annoys high altitude balloon hobbyists.) I expect (but have no source) that there are military grade GPS chips that are designed to go ballistic - you'd want that if you were an authorized ICBM manufacturer, wouldn't you. 88.112.41.6 (talk) 20:14, 14 November 2013 (UTC)

I believe that no "very powerful" GSM phone would work, because the speed the phone is travelling at would be so fast that the "handshake" between cell masts and the phone would make it impossible, and the phone would be visible to many cells at the same time, which wouldn't work. — Preceding unsigned comment added by 217.158.236.14 (talk) 14:21, 14 November 2013 (UTC)

However Iridium phones are not cell phones, and connect directly with the satellites, not via a ground station. Would this help? Rojomoke (talk) 17:48, 14 November 2013 (UTC)

I'd bet that this would have the same problem as the GPS. The phone has to figure out which satellites are overhead and where they are moving...and I'd bet that the configuration of satellites would change more rapidly than the calculations could be performed...that's true of GPS - but I'm only guessing for Iridium phones. SteveBaker (talk) 17:53, 14 November 2013 (UTC)

(ec) Our Cell site article says that the range of a cell tower is limited (in part) by: "Timing limitations in some technologies (e.g., GSM is limited to 35 km, with 70 km being possible with special equipment)". Which probably means that the tower and the phone are required to exchange some kind of signal with a round-trip time of maybe 1/5th of a millisecond - and that would be flat out impossible with the speed-of-light transit time to the 425 km-high ISS orbit being at least 1.2 milliseconds. So I'm pretty sure GSM won't work - but CDMA/IDEN phones don't have that restriction. Orbital speed might also be a problem - a typical cell is one or two kilometers across and the ISS is moving at 7.65km/sec - that would require it to switch cells maybe 7 times a second. Ironically, it might do better over rural areas where the towers are spaced further apart (maybe up to 60km apart) - which might give the software in phone and cell tower enough time to switch towers.

GPS is much more problematic - the difficulty being that when on the ground, they have to take account of relativity in order to get accurate positioning - they know the speed of the satellites in orbit - so they can do that. However, I'd be quite surprised if they bothered to take account of the speed that the GPS unit itself is travelling...and since the speed of the ISS is so high, I'd assume that would cause intolerable errors. Another issue with GPS is that it has to do protracted searching to find the satellites whenever you turn it on after moving it more than a few miles. With my GPS, it sometimes takes several minutes to get it all sorted out. I suspect that in the ISS, the configuration of visible satellites would change faster than the calculations could keep up and it would never lock on.

So, I'm fairly sure, the answer is "No" for both things...but it's not about radio propagation distances - it's about software performance and subtle issues like that. SteveBaker (talk) 17:51, 14 November 2013 (UTC)

I would think the ISS and orbiting satellites would use reverse GPS. Well known ground reference points, receiver in satellite that picks them up. Multiple radar installations could track very accurately where, what altitude and velocity objects in space where traveling with similar precision to GPS (error might be slightly higher due to length of transit in atmosphere). Bouncing a timed and coordinated signal from one source on earth to a satellite and back to multiple receivers on earth at different, known, locations accomplishes the same thing as GPS. Just need a powerful radar and sensitive receiver.. --DHeyward (talk) 08:32, 15 November 2013 (UTC)

Reverse GPS is a great idea. However, unless you're travelling on a much higher orbit (ISS is about 400 km above the ground), your horizons are quite limited (ISS: a 2300 km radius circle).

http://www.ringbell.co.uk/info/hdist.htm

This means you must install many many many radio beacons on land. And when the ISS is over the Pacific Ocean, it may only see a handful of beacons on some islands.

However, if you're on a much higher orbit, this idea may work! -- Toytoy (talk) 12:56, 15 November 2013 (UTC)

Duel Electric Meter for saving money?

I live in Michigan and have moved into a house that is electric everything and each room (10 in all)has it's own thermostat. I have been told that we can save money by having a duel electric meter put in if our electric company (Consumers Energy) provides this. What exactly is a duel electric meter and how can it help us save electricity? Officerswife (talk) 02:14, 14 November 2013 (UTC)

I don't know what it is but it's likely spelled "dual" as in two of something rather than "duel" as in a sword or gun fight between two people. A Google search confirms that there are such things as a Dual Electric Meter but I haven't been able to figure out what they do. Dismas|^(talk) 02:20, 14 November 2013 (UTC)

This talks about dual rate electricity but it seems to center on the UK, so I'm not sure how much it would apply to your situation. To my knowledge, we only have a single rate charged to us for electricity here in Vermont but Michigan may have two like the article discusses. Dismas|^(talk) 02:25, 14 November 2013 (UTC)

The article cited by Dismas talks about off-peak electricity delvered via the second meter. This can work well, lowering your electricity costs if you have storage hotwater systems and/or storage space heating - you mostly want heating in the evenings, which are off-peak for the power company, anyway. You can aslo run a small oven from the off-peak meter, so that if you like late (or even early) evening snacks, you can cook them on cheap electricity. You may alternatively have a system used by power companies elsewhere. The second meter is set up to charge at a slightly lower tariff, but the power company has the right to turn off the power to it when demand is high. They usually only do this for short periods - under an hour. You need to consider the usage of such power carefully. In hot weather, if your airconditioning is fed from the low tariff meter, it can result in increased electricity charges, as your aircon will go like the clappers to catch up when the power comes back on. 60.230.232.138 (talk) 03:05, 14 November 2013 (UTC)

I live in Michigan, and have dual meters, as our house was once set-up for an upstairs tenant. However, just having two meters alone may actually cost you money, since now you have 2X the flat monthly rate. However, there are so many plans it's difficult to tell, without analyzing your usage patterns:

1) They have "off-peak usage plans", as mentioned above, which typically charge more at peak times and less at off-peak times. That might require a dual-meter.

2) They have "interruptible service" which promises they will only interrupt it in an "emergency", but my brother had that, and every hot day was considered an emergency, with the result being that he could only use his A/C on days when he didn't need it. This might require dual meters, one for the interruptible "non-critical" portion of the service (used for A/C), and another for the rest.

3) They have "senior plans", where they charge a lower rate for light usage, and a higher rate for higher usage. I see no reason for a dual meter here.

4) They have lower rates for those with whole house electrical heating. If the heating unit is on one meter at the lower rate and the rest of the appliances go on the other meter at the higher rate, that might explain it. I think this is the case you have. Yes, that could reduce your bill. However, even at the lower rate, electrical heating is still far more expensive than gas heating. StuRat (talk) 03:30, 14 November 2013 (UTC)

Electric heating on a separate meter is also my guess - but electric heating is unusual in Michigan (only 8% of homes)[6]. Consumers Energy calls it Heat Plus Metering [7]. Rmhermen (talk) 18:36, 15 November 2013 (UTC)

Do they not have smart meters in Michigan? I have a single meter that is remotely read and has time-of-use rates. I am not sure how having two meters would be used for multi-rate service. Dual meters are used for solar and other grid-tie systems as they measure the power that is put back on the grid. If you house isn't designed to have multiple service entrances, I don't see how splitting up the service is possible or efficient. Is there a penalty for exceeding a certain amount of kWh per month? Is your house underpowered for a heat pump or central heat such that someone is recommending a different heating system on it's own service? StuRat's #4 sounds most likely (and also can't be turned off in winter by law). --DHeyward (talk) 07:20, 14 November 2013 (UTC)

They have "smart meters" designed to broadcast whether we are home or not to nearby thieves, yes. However, they don't broadcast on the Internet, but only to the street, so the meter readers need to go around in a vehicle to take readings. Unfortunately, the portable units they use to read the meters from the street have a seriously underpowered battery, and the utility company requires the employees to return to base to verify that the battery is dead and get a replacement. Rather than deal with this hassle, the employees instead continue to read the meter manually, just as before. :-) StuRat (talk) 08:20, 14 November 2013 (UTC)

Wow. I believe ours use the power-line for data transmission and is updated daily. The meter is addressable and queryable. Everyday, the power company posts usage (down to the hour) on my account. It's not 100% as sometimes it updates at midnight or 4am but it's correct. My meter is supposed to be physically accessible but I created a courtyard with a gate (the Fire Department could get in, but the power company would have complained if they had ever checked in the last 5 years. They phased out the meter readers. The gas company and the water company read by hand with the gas company being the least efficient. --DHeyward (talk) 10:26, 14 November 2013 (UTC)

That's what my Michigan smart meter is like. It actually lets you break it down to the minute if you want to. — Preceding unsigned comment added by 209.131.76.183 (talk) 12:32, 14 November 2013 (UTC)

Solar power systems have become common in Australia due to the stupid Government heavily subsidising the installation, and imposing a tarrif for power fed back to the grid much higher than for power drawn from it. No additional meter is required - they have new technology meters that store the amount of electricity fed back separately from electricity drawn off. But dual tarrif (either off-peak or off-in-high demand) are much older ideas that have required dual meters. 60.230.232.138 (talk) 08:56, 14 November 2013 (UTC)

Net metering (the solar meter) is usually required by the local city/utility code based on fire codes (NFPC/NEC) and also allows the utility to lock it out safely. Even though the inverters are suppose to cut out without a grid and there is both a DC and AC disconnect, removing and locking out the meter is the way the power company controls the service entrance. One of the the codes that makes solar ugly is that it's not allowed to penetrate the roof or a wall until it hits the service entrance disconnect and meter. Because of utility laws, only regulated companies are allowed to sell electricity to consumers (i.e. homeowners can't install a sub-metering system to tenants, but a power company can) so a meter is almost always required between the solar power and the consumer. I always wanted to forego the solar array and use off peak cheap energy to charge deep-cycle batteries and then connect the batteries to the solar inverters during on-peak hours. It's almost as cost effective as the raw cost for solar but they won't give me a tax break to buy the batteries. The break even point is around 12 years for current prices. --DHeyward (talk) 10:26, 14 November 2013 (UTC)

That must be a quirk of DHeywood's power company or of the US National Electrical Code (NEC). Or error by DHeywood. DHeywoods's requirement that the solar invertor output be routed to the meter/service connection point before entering the building cannot be applicable in Australia. We have what are known as "battle-axe" blocks. This is a way of saving money on roads. Each roadside in a battle-axe area has residential or light industrial blocks of land fronting the street, and another lot of blocks behind the roadside blocks. The "behind" or rear blocks get their access via drive-ways running down the side of the road-fronting blocks. Hence the name "battle-axe" as that is what it looks like on the title deed survey drawing. To make life reasonable for the meter readers, all gas, water, and electricity meters are installed at the road/street end of the driveway, and there is typically 100 to 300 m of gas-pipes, water pipes and electric cabling from the meters to the house or factory. If the owner of a battle-axe block installs solar power, the power company replaces the meter (and charges a fee), if the existing meter is an old type. But nobody installs additional cabling so that the solar can go via the meter - that would be very expensive, involving trenching, the new cable, filling-in, and re-instatement of the driveway surface, macadam, bitumen, or concrete, whatever it may be. Many $1000's. Who wants cabling running across their roof, over the eaves, and down the side of their house anyway? Not sensible. If the cable is correctly sized and fused, fire is extremely unlikely, virtually impossible, and it is much safer concealed inside the structure. Most invertors are not rated for external installation (ie they are not weather-proof and/or cannot tolerate direct sun) - they can be installed outside in porches and the like however, so long as the sun and rain cannot reach them. 60.230.247.177 (talk) 11:41, 14 November 2013 (UTC)

It's a hazard to fireman if they cannot easily disconnect it before entering a structure. It's a hazard to have undisconnected electric service (AC or DC) penetrating the roof or wall. So it stays outside for residential installations. Commercial installations sometimes have a service entrance utility room where everything, including the meter and disconnect, is in a room (the fire department has keys). Short of a blanket or night time, there is no way to stop the string of panels (which are often wired in series to provide upwards of 400VDC) from providing a hazard to firefighters so the DC pieces from the panels to the inverter never penetrate into a living space. Designs usually treat the solar array as a source when doing fault analysis so there are a number of calculations and requirements for disconnect before power from an array can enter the home (in the U.S. for example, the backfeed into the main panel is often done in the breaker position farthest from the other source. This is to limit the current into a fault generated in the middle of the panel. Large solar installations to existing services often require the main breaker be derated as the rest of the equipment would not be fault protected from the maximum setting of the breaker - i.e. a 2,000 amp service has components that are not rated for more than 2,000 amps. If you add a solar array that can supply 200 amps of additional current to a fault, a component may have more that 2,000 amps available to it. The main disconnect breaker has to be derated to account for these types of faults.) Grounding is also an issue with PV systems as what and where to ground is critical as there can always be a short-circuit current (sometimes in the PV panel itself). Most of the residential solar installations just follow the cookbook which is solar meters, mechanical disconnect at the service and no structure penetrations. Rules are covered by NFPA 70 (NEC) section 690 (www.nfpa.org). The electric code is written for fire safety (both for fighting and preventing them as well as protecting public from electrical hazards). Grid tie inverters are service side wiring. I don't know how Australia does it. --DHeyward (talk) 08:15, 15 November 2013 (UTC)

Rotor in a cylinder

Would a rotor generate more lift if it's inside a cylinder instead of spinning in an open space? Intuitively, I imagine that the cylinder will canalize the flow in the right direction. However, it seems a too simple of a solution to remain unimplemented. So, are both scenarios different? OsmanRF34 (talk) 19:02, 14 November 2013 (UTC)

You mean something like a Ducted fan? AndyTheGrump (talk) 20:58, 14 November 2013 (UTC)

Yes, I have something like that in mind, but also for ships. OsmanRF34 (talk) 23:35, 14 November 2013 (UTC)

Ducted propeller, Bow thruster. AndyTheGrump (talk) 23:38, 14 November 2013 (UTC)

Pump-jet and vectored thrust are related. StuRat (talk) 05:00, 15 November 2013 (UTC)