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Batteries Continue To Suck
pvt_medic writes "As technology continues to grow, and we see more and more of a shift to portable electronic devices in our daily life, we are still constricted by one simple thing: Batteries. Newsweek has an interesting article about the lack of development in battery technology. 'Ironically, in our headlong rush to create sophisticated untethered computing, the most problematic technology turns out also to be the oldest: those nondescript metal cylinders that never seemed to be included with our Christmas toys.' And for those of you who would like an extensive overview about batteries, ExtremeTech.com has a nice overview."
lets make with the cold fusion already.
turn up the jukebox and tell me a lie
Seriously, what about all those great Slashdot battery articles we've seen over the past few years? The amazing advances that were supposed to revolutionize our portable electronics? I've been wondering about them recently. Was manufacturing these theoretical advances just too difficult?
"nondescript metal cylinders that never seemed to be included with our Christmas toys"
Why is he talking about Nukes? I mean, yeah, you never seem to get them (Top of the list, five years running! But do my parents see fit to get one? NEVER!), but what place do they have in an article about batteries?
When life gives you crap, Make Crapade.
Sluggy Freelance.
There is actually a real use of these, see http://www.ballard.com/tD.asp?pgid=700&dbid=0
Its pretty cool, because you always hear about fuel cells, but almost never see a commercial application.
Hopefully once they make it smaller...
"Had batteries advanced at the pace of the computer processor, a double-A cell would contain more energy than a tactical nuke." - Paul Saffo
I suppose that would be somewhat hazardous wouldn't it.
At least a current day leaking battery will leave a nasty burn mark on my table, not burn thru the table and into the concrete floor underneath.
"The worst tyrannies were the ones where a governance required its own logic on every embedded node." - Vernor Vinge
The adult industy is the answer! They just need to make less efficent vibrators, than something will be done.
Quit bitching or open-source the laws of physics.
"Learning is not compulsory... neither is survival."
--Dr.W.Edwards Deming
Seiko has a watch that runs based on your arm motions. Think Geek also sells a flashlight that recharges itself by jacking it off.
Do you even lift?
These aren't the 'roids you're looking for.
Alkalines have high internal resistance, which makes them poor candidates for cameras and other high-current applications. Alkalines rule for transistor radios, etc, where you have miniscule current draw.
I want to delete my account but Slashdot doesn't allow it.
They could be built now, from radioactive waste, using the same really simple technology used aboard space missions..
Such a small amount of material per battery would make it safe, but would last years... ( not forever, but with teh way things are designed these days, at least long enough for the device to fall apart...)
---- Booth was a patriot ----
If only we could harness all of our wasted energy. Like those watches that gain power by your movement. Devices should be looking to get energy from as many sources as possible. Solar, moving etc. Do I have the answer on how to do this? Hell no, I'm just some punk on Slashdot with crazy ideas that are technically impossible. When *they* create wireless power, I'm definitely investing in their business.
"If you are a dreamer, a wisher, a liar, A hope-er, a pray-er, a magic bean buyer
Yes, yes I'm sure it all comes down to greed. Because you know, there's no way they wouldn't price longer lasting batteries higher than lower costing batteries. I mean to make up for the loss in volume. Oh and there's no incentive for any of the various battery companies to one-up their competition and grab market share by making a more efficient/longer-lasting battery. That's why we see that energizer bunny all the time, because it's unprofitable to sell batteries based upon length of life.
The key to the enjoyment of pop music is to replace any instance of "love" with "C.H.U.D."
power, size, and longetivity: choose any two
filter: +3. Hey, look! all the trolls went away!
"Fuel Cells:
The wonderful side of this dream is that some engineers expect it to be reality by the end of 2001"
Err... whats the hold up? Are they finishing duke nukem first?
Best Christmas present ever:
Pack of batteries with label: Toy not included.
-Adam
I commute by bicycle. Now that it is getting dark early, and I bike through heavy traffic, I have several bike lights:
- One 10-Watt halogen light with a lead-acid battery. It's lasted me for several years, but is starting to loose it's charge.
- 2-3 blinking lights which take any old AA & AAA batteries.
I'm getting sick of having to toss the discharged alkaline batteries all the time, and am looking for a replacement.
Since I'm comparing the prices of the different kinds of batteries and chargers, I'd also like to compare the different toxicity levels.
Are NiMH's safer then NiCADs or Alkalines?
Ironically, my lead-acid battery gets the most frowns, but it seems like it's actually one of the least toxic options. There are several places near me which recycle lead-acid batteries (They strip the batteries, neutralize the acid, and take the lead; all in-house).
"Can of worms? The can is open... the worms are everywhere."
It's not batteries that are the constriction, it is slow IO hardware.
Imagine what you could do if your hard disk could read data as fast as your processor could handle it (think RAM-like or cache-like speed)
A few years ago I got to meet with some folks from Eveready and a number of charge controller companies, and trust me, there's quite a bit of R&D that goes on.
For disposables, consider that we've gone from carbon-zinc to alkaline to lithium chemistries. In the case of Eveready, they have the L91 lithium AA, and it's pretty amazing in terms of power density and battery life (about 3X alkaline.) It's now about 10 years old.
Rechargables have gone from lead-acid to Nickel-Cadmium to Nickel Metal Hydride and also Lithium-Ion.
Keep in mind we're talking about a chemical device here that's storing larger and larger amounts of energy as times goes on. More energy = more potential for bad things to happen. Since it's chemical we're dealing with chemistry, materials science, and environmental factors (heat/cold, issues of outgassing, etc.) There's a lot more going on than a simple metal tube here.
A lot of the work that goes on is hidden -- it's hidden in the fact that the battery works for more than a few cycles. Many battery chemistries are very touchy when it comes to repeated cycling, for example, while others if not formulated (or charged) correctly would outgas or swell and explode. If any of you remember the good old days of carbon-zinc, it was routine to have things destroyed by leaking cells. That's one of the reasons the battery manufacturers actually offer warranties on the devices using them. (Think about that: It's like Exxon giving you a warranty on your engine if the gas harms it.)
While the future is probably fuel cells (I'd bet on methanol cells in particular, perhaps like Neah Power is working on) it'd be wrong to think that batteries aren't improving -- or that they won't be around for a long, long time.
Obviousally the writer is so young as to not remember the evil that is the NiCad battery.
Today's batteries are unbelieveably nice and great compared to the utter crap we had to use just 7 years ago.. NiCad batteries would get a memory effect, last very short times and have abyssimal storage capacity.
batteries have came a long way, and they will continue to improve... how about making processors and displays that dont suck down amps of power?
the problem isn't the batteries, the problem is the horrible inefficency of today's tech!
Do not look at laser with remaining good eye.
All the big gadget people out there (including me) are all waiting anxiously for fuel cells to come along and give us super long usage times for our devices. But what I suspect will happen is that fuel for fuel cells will become the next ink jet print cartridge, with manufacturers charging insane prices for refills. The price you pay for plugging in your laptop will be a fraction of what a single fuel cell refill will cost. And of course you can expect the same manufacturer technical lock-ins as ink, except now with even more warnings like "Use of non-approved refills will result in EXPLOSIONS AND DEATH, buy only certified refills UNLESS YOU ARE INTERESTED IN BLOWING YOUR HEAD OFF. You've BEEN WARNED, JACKASS!"
1. If there was a chemical reaction that could produce energy on the nuclear level, it would disrupt nuclear processes - So whatever elements it happened between would transmute each other on contact. Look around. Do you see any natural element below the radioactive ones on the periodic table that is undergoing alchemical style (i.e. lead to gold style) transmutation to another element? No? Then there is a peak limit for how much power you can get out of any chemical battery, and it's lower than the weakest natural nuclear reactions observed. 2. The most electromotive elements are the reactive metals, like Potassium, Calcium, and Sodium at one end, and Florine and Clorine at the other. The reactive metals burn on contact with cold water, and the problems with handling the reactive gasses are legion. Batteries generally work with an anode and a cathode of two different mentals or metal compounds. Electrodes are generally made from metals in the middle of the electromotive range, like Pb, Cd, Cu, Ni, and even Hg, and their compounds. To get better energy storage per weight than zinc, nickel or cadmium just about always means working with something more reactive for at least one electrode. So "better" batteries are generally more environmentally damageing, or pose bigger health risks to humans working with them. 3. There is a metal with electromotility better than oxygen or clorine gas. It's called Gold. Unfortunately it is hard to get gold to react with chemicals, it's heavy, and it's just a touch expensive.
Who is John Cabal?
The public accepts the idea that batteries die and need to be replaced, so therefore, battery companies make money. What would be their incentive to create better batteries? So that the public would have to purchase them less frequently? Then we'd probably just end up paying the difference for the better battery. I doesn't sound like a good business model to take a cut in profits to make everyone's life a little bit easier. I don't really think there's much of a public demand to reform the battery industry, so therefore there's no need to do so for the industry. Just keep up with the technology.
I guess on a side note, my rechargable batteries are a godsend. While you can debate the economics of it all (40$ for a charger and 4 batteries), I just like not having to worry about having batteries for my MP3 player [Nike PSA64]. I use it primarily for working out, I go through a battery every week or two, throw it in the charger, and then replace it. They've lasted all summer and still give me numerous days of life. Prior to purchasing them, I was going through batteries like a mad man, buying a pack every two weeks to keep up with my working out. I think its the best solution for anyone who goes through a lot of batteries...
"In a Democracy, people get the kind of government they deserve." -Winston Churchill
How is it that "batteries don't last as long as I'd like" turns into "there's no development put into batteries" in some people's minds? There's lots of time and money put into developing better batteries because if someone creates the better battery they will make lots of money.
The lack of headway is the chemistry, not the funding or effort. There's a finite limit on the amount of energy you can safely store and retrieve chemically from a given volume. A lot of development is focused on getting higher energy/volume ratios, lithium polymer and methanol fuel cells are good examples of this branch of development.
Looking for better battery chemistries is much more difficult. Between environmental concerns and ridiculous patents trying to market new chemistries isn't a cake walk for any company. There's a lot of materials that can be used in batteries. Not all of them are things you want ending up in land fills or in the hands of complete and utter morons.
I'm a loner Dottie, a Rebel.
Try the local hobby shop, or look for one of these. You can easily charged old ni-cads or NiMh batteries in less than an hour using a 'peak detecting' charger like that. Overnite chargers run at .1C or less (C = battery amp hour capacity) and can be left on w/o overheating. The fast chargers blast 'em with 1 or 2C which works, as long as you cut it off when they are charged or they overhead and get damaged. The 'peak detecting' chargers can tell when the battery is full and automatically shuts off. Works great.
try { do() || do_not(); } catch (JediException err) { yoda(err); }
Actually, the greatest (and most under rated) inventor in western history, Nikola Tesla, has already created it. For some unknown reason, J.P. Morgan refused to back it.
1) Energy in a given space has nothing to do with exploding. TNT doesnt explode without a detonator, Plutonium needs a critical mass and a neutron source, etc etc.
2) Since the original electricity is a trivial cost of batteries, the question is how much energy we can keep in the battery, not how much we use to get it there, so this is utterly irrelevant.
3) Vacuums apply to pressures, not energies. Have you seen the sun exploding lately because it's more energetic than the surrounding vacuum? (No, sorry, flares dont count.)
Real problem with batteries: inorganic chemistry hasn't made any huge progress lately.
Solution: capacitors. GM is planning to use them instead of car batteries in the relatively near future.
U.S. War Crimes blog. Email for free Mandriva support.
Fuel cells suck ONLY because no one ever commercialized fuel cells 30 years ago.
Fuel cell technology should have been the next leap forward. But it's taken a long time because most investments in fuel cell has been centered around space applications... where light weight, high-performance electrical power is a requirement.
An incredible amount of fuel cell technology was developed in the 1960s and 1970s for space programs - and when you make money on space programs, the bean counters know that there is no reason (financially) to look at other potential markets. That was simply a sign of the times.
Unfortuantely, now most fuel cell expertise has been lost to the retirement of industry experts. Much of the "innovation" in recent years is merely a rehash of research done 30 or 40 years ago, but forgotten because no one back then had a vision for using fuel cells to replace (terrestrial) batteries.
I contend that many modern fuel cell related ideas and patents are really old ideas that have been rediscovered by a new set of researchers unfamiliar with the developments of the past.
It's like we just lost 30 years of ful cell development... too bad, because if the corporations that originally developed this technology had their shareholders in mind, they'd have a slightly longer vision and would be leaders in a new industry.
Ok, it's old but it's still amusing:
Q: What happens when you put the batteries in the Energizer Bunny backwards?
A: He keeps coming... and coming... and coming...
Help save the critically endangered Blue Iguana
This one is the Shimano NX-30, and it will power a 6 watt front headlight.
Maybe not as bright as your old 10-Watt, and sure, there is a little drag, but it's not bad, and you get to stop charging your bike lights for good. And $60 for the functionality of a battery *and* a front hub is a good deal.
spreer
Having just attended a Canadian Forces Naval briefing on this very topic, I'm glad you asked :).
Naval subs use massive "wet" batteries, something akin to what your car uses, except exceptionally massive, typically filling two large-ish rooms. They are exceptionally heavy.
Note that diesel-electric submarines are only rated to run for aat most two weeks between charges. They have to surface to run their diesel engines in order to recharge their batteries, as the diesel engines need clean air for the combustion, and need to be able to vent their exhaust gasses.
This is a disadvantage over nuclear submarines, which can stay down for months at a time. The benifit of them, however, is that diesel-electric subs are quite a bit more silent than their nuclear counterparts :).
Yaz.
A battery that knows whether or not it is in use. Perhaps it would be possible for another voltage to trigger the chemical compounds in the first place, that is, when there is no voltage across it, the chemicals are relatively inert. A while ago I read (possibly on slashdot?) of a substance which is a liquid when any current is going through it, and a jelly-solid when it isn't.
Now the downside to this avenue is that each battery would have a battery (likely internal). However this wouldn't have to be nearly as big-- by design, make a very low current required to start/stop the chemical process in the larger battery, which is now free to be much more caustic in nature. Now the battery may still explode from mal-use, then again a passive fuse element could also be added which makes sure the battery permanently becomes in it's inactive state.
I'm not saying we know how to do half of this, it's just one option we can persue. Another option is fundamentally chance the amount of electricity anything handheld uses. This would be happening right now, but every time we make something more efficient, we make it faster so that it's consumption is more or less equal (usually more).
I find that my 1950 mAh NiMH rechargeables last longer on each charge (> 10 hours) than brand-name alkalines, let alone the Sorny versions that choke after a few hours in my mp3 player. You can probably pick up a charger and 4-8 battaries for $30-40. For me it paid for itself in a matter of weeks, and I don't constantly find myself without batteries for my walk home.
"Now gluttony and exploitation serves eight!" - TV's Frank
The instructors was somewhat insane, but what he said makes sense. He's also a considered a leading authority on Extra-Terrestrials. For as insane as he was, they classified a bunch of basic research he did into application of nuclear physics. You also couldn't find a problem in the book he couldn't solve. He was really smart about his physics, and it's applications. He taught all of the electronics classes.
It's also backed up by my emperical evidence of picking up the light bulbs that are 130v instead of 120v last longer in fixtures over the last 5 or 6 years. They aren't any more expensive then the bulbs you pick up a Walmart.
Kirby
The non-rechargable batteries gotten much better, going from the Zinc cells to the modern alkalines -- the capacity has gone up greatly (a factor of 10 or so?) And then there's the non rechargable lithium cells that can hold MUCH more (and costs more too, of course.)
Also, and perhaps even more importantly, the rechargable cells have gotten much better recently. Maybe fifteen years ago, you'd buy 500 mAh AA NiCd cells ... now most people buy 1800 mAh NiMH cells, and for a few dollars more, you can get 2100 mAh AA NiMH cells.
(Quick aside, NiCd vs. NiMH: NiMH have more capacity, but usually cannot deliver as much current in a very short period. NiMH cells do not suffer from voltage depression (often mistakenly called `memory'). NiMH cells are not as environmentally unfreindly as NiCd. NiMH cells usually don't last quite as long as NiCd cells. But for the most part, for most applications, NiMH and NiCd cells can be used interchangably.)
And more recently, Li-Ion and Li-Poly cells have really come of age. These cells often have energy densities and power densities several times greater than what NiCd and NiMH cells have. Li-Ion cells were extremely fragile and could not handle abuse at all, but the new Li-Poly cells are overcoming many of these shortcomings.
Ten years, electric R/C planes were very rare. Now, thanks mostly due to the improvements in batteries, they're found all over the place, and they can perform just as well as the glow and gas powered planes in many cases. All three types of batteries (NiCd, NiMH and Li-Ion/Li-Poly) have improved greatly recently, and all three are quite popular with pilots today.
(Li-Poly especially looks incredibly promising for the future -- today, some planes with motors powered by them can often fly a full hour on a single charge, and things are getting better all the time.)
In short, I don't agree with Michael Rogers at all -- there's all kind of developments being made in batteries. It's just that they're not happening fast enough for him :)
(Semi-relevant aside: I have a TRS-80 Model 100 laptop computer. It's powered by 4 AA batteries, and it lasts a very long time. Perhaps the problem isn't the batteries -- maybe it's the laptop makers who use CPUs that use so much power!)
What happened to the super capacitors? You know, caps with such a high energy density that they could be used to replace batteries in many applications.
Nonsense.
1 Farad = 1 Amp at 1 Volt for 1 Second
As anyone who knows capacitors can tell you, a farad is a huge unit. To put things in perspective, common, everyday capacitors often have capacitances measured in picofarads (a picofarad is one-thousandth of one-billionth of a farad).
Now, how much capacitance would it take to equal a single AA battery?
A typical AA battery might be rated at 2200mAH at 1.5V. It doesn't actually keep that voltage up the entire time, but let's just pretend that it does.
2200mAH = 2.2AH = 7920As
So, a typical AA battery delivers 7,920 amp-seconds at 1.5V. An equivalent capacitor would need to have a capacitance of around 11,880 farads. That's to equal ONE AA battery. No such capacitor exists, and even if one did, it would be absurdly dangerous to handle.
The strength of a capacitor is its ability to deliver its power very, very quickly. That's why a big capacitor would be so dangerous -- imagine discharging all of the power in a AA battery in a ten-thousand of a second. The strength of a battery, on the other hand, is its ability to deliver (relatively) unbelievable amounts of power, but it can only do so over much longer periods of time.
ZFS: because love is never having to say fsck
Of course our million dollar tanks, at least at this time, were equipped with cheezy aluminum tools. One a buddy of my uncle was tightening the lugs on a battery and crossed both terminals. The tool literally melted and burned in a flash.
"Learning is not compulsory... neither is survival."
--Dr.W.Edwards Deming
Moderators, in what way exactly is this "Informative"???
I'm sorry, but cheap alkalines are a good solution if you have a flashlight that you hardly ever use but that's about all they're good for. It does nothing for the case of the laptop or PDA, and they're envinronmentally unfriendly for anything that is used a lot or has a high draw.
130V bulbs last dramatically longer because their filaments run much cooler than 120V bulbs (they have larger and thicker filaments, hence a greater surface area to dissipate heat). This is great for longevity, but it comes at a heavy price in efficiency. The lower filament temperature shifts the bulbs emission spectrum towards the infrared (Planck's Law) reducing the amount of visible light produced. This reduction in efficiency will require more electricity to produce a given amount of light. When all is said and done it takes far fewer resources to make higher temperature bulbs that are more efficient than to keep one long life bulb chugging along. Of course, if resource/energy efficiency is a concern halogen and fluourescent bulbs are far better than any conventional incandescent.
There are also other techniques to increase the longevity of regular bulbs. Since the most likely time for bulb failure occurs at switch on, using a switch that only activates at a zero-crossing of the voltage waveform minimizes the turn-on stress. The inrush current to a cold bulb can be on the order of 10x the running current (an incandescent filament is an extremely non-ohmic load because its resistance varies dramatically with temperature). It's this high current that causes high stress on the filament (the motor effect can cause the filament to twist violently). From what I've read, this technique is often used on navigational beacon lights (these lights also use over-rated bulbs to gain lifetime at the expense of efficiency).
Another technique to minimize turn-on stress is keep the bulb running 'warm', that is to pass enough current to keep the filament at a temperature just below that needed to produce visible light. The relatively high temperature raises the resistance of filament, thus dramatically reducing inrush current. According to some theatre techs that I know, this technique is extensively used in theatre and television where a light failure could ruin a show.
Note that you can also charge such subs while in dock, by running cabling to a charge port (no kidding!).
Obviously, you need to pick and choose what types of missions you use such subs for. As I mentioned, they aren't for long-duration underwater missions. They serve a different purpose than nuclear subs serve.
And BTW, the Canadian Forces routinely detects the US Los Angles-class nuclear subs while they're supposedly running in "quiet" mode :).
Yaz.
I just saw one of the Los Angeles class subs. They are indeed impressive machines.
I'm not trying to slight the US's nuclear subs. They're obviously not rusty old junk buckets making a racket that any old fishing trawler can pick-up. They're exceedingly advanced machines.
However, if you run a decibel test between a Los Angeles class sub and one of the Canadian Forces Victoria class diesel electric subs, the Victoria class scores better. They have their own issues, of course (the Victoria class subs needing a whole lot of work to make them seaworthy for one thing :P)
Yaz.
Yes, reactors are noisy relative to batteries. They have hot fluids being pumped around in heat exchangers and driving generating turbines.
Listen up all y'all. It is time to testify.
Maybe the problem isn't the batteries, maybe the problem is what we expect them to do. Sure a laptop that runs Unreal Tournament 2003 at 100 fps is nice, but when was the last time you saw anyone playing it off their battery.
Portable eletronics will always need to be more rugged and less power hungry then their stationary brethern, without exception, no matter how good batteries get. So here is a bright idea.(let me know if this gets too deep for you) How about we stop expecting portable electronics to be as powerful as non-portable electronics?
Sure try to make better batteries, work as hard as you can at it, but keep in mind what Lone Star said to the Druish Princess Vespa: "Take only what you need to survive"
No, and by that I mean zero, laptops need a DVD-R. Almost no laptops need any 3D accelerator. Why, on god's green earth, do cell phones need a camera? Why does a PDA need enough hardware to play videogames? Do you buy a cellphone for a camera? Did you go shopping for a portable video game system and say to yourself, "Hey this GBA is pretty cheap and has really good games, but I am looking for something that is 4 times as much and is hard as hell to play games on?"
Opmization is what must prevail. Making one machine that does everything, will not work. Give the people what they need. No one is buying a phone for its camera. They buy a camera for that. Power saved. No one needs to burn a DVD while flying from New York to LA. Power saved.
I mean look at the Game Boy. The first took 4 AAs and lasted 4-6 hours. The Game Boy Color took 2 AAs and lasted 10 hours. The Game Boy Advance takes 2 AA and lasts 15 hours. Batteries have not gotten that much better, but today's Game Boy users are spending 1/8th as much on them.
Programmers need to care about memory and processor usage again; engineers need to care about power consumption again. Do you really think that an mp3 player really needs to take 20MB of space? Power saved.
Batteries aren't the problem. People are.
SW
When you switch one on, the tungsten filament is still cold, and - like most metals - the resistance of the filament is lower at lower temperatures.
This is what causes a major surge in amperage, and this is what actually 'breaks' the filament. The cold period lasts only a split second, but this is enough to fry a weak spot in the filament.
The weak spots are formed during 'normal' use, since it is virtually impossible to create a wire with even with along its entire length. A part that is only marginally thinner than the rest, will have higher resistance and hence voltage drop and power dissipation than the rest of the wire. This higher temperature will cause the tungsten to evaporate faster, and condense slower, on the already weak part of the filament - causing the weakness to get weaker until in eventually poops out under start-up conditions.
The funny thing is: some ordinary bulbs can run for decades continously, but don't even think of switching them off and on after that!
That bit about NiCd batteries having "memory" but not NiMH? Not true. Yeah, they got the crystalization part right, but they ignored the usual cause. Too many people (manufacturers and users) used dumb chargers and overcharged the batteries causing them to release hydrogen and oxygen. The resulting charge/discharge curve led people to think this was the memory effect, when it really wasn't.
Battery chargers today are much more sensitive to the charge state of a battery and as a result they're much less likely to overcharge a battery.
According to the GE manual on NiCd batteries, there really is a "memory effect" on NiCd batteries, but it relates to their use on board spacecraft in orbit where charge and discharge cycles are very regular. This effect is slightly different from that which results from overcharging the pack. Most people don't charge and discharge their battery packs so regularly.
In the case of the batteries in orbit, the full capacity can be restored by one or two irregular charge/discharge cycles. However in the case where you overcharge the batteries, you actually lose capacity in the battery.
By the way, overcharging a NiCd battery is less damaging than overcharing a NiMH battery. The former can recover some of it's capacity by exposure to air to recover the hydrogen and oxygen gasses it released, but the latter generally doesn't.
Nearly fifty percent of all graduates come from the bottom half of the class!