Suspended-Load Backpack

[far-trader]

So, here's a new toy for the locker...

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The Suspended-Load Backpack not only carries a heavy load with ease but allows soldiers, rescue workers, and field scientists who rely on several electronic instruments such as comms and sensors to maintain the batteries while on the go and far from rechargers.

The backpack is designed to make use of the natural up-and-down motion of a person's stride to generate electricity, either for immediate use or for storage.

Consisting of two main parts – a rigid frame strapped to the wearer's back and a load plate suspended from this frame by springs - as the person walks along, the load plate slides up and down the frame.

Attached to the load plate is a toothed bar that turns the gear of a generator affixed to the frame. As the bar turns the generator's gear it generates up to approximately 8 Watts, depending mostly on the actual load carried.

The frame weighs 4kg and the pack can hold up to 36kg and generates about 1 Watt for each 4.5kg carried in the pack.

Wearing the backpack will actually cause the wearer to alter their gait, causing them to walk more efficiently and burn less energy, more than offsetting the minor weight of the generator.

The springy pack also decreases the amount of force placed on the wearer's shoulders, making the bag more comfortable.

Because of these unexpected finds this technology has all but replaced conventional backpacks.

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Suspended-Load Backpack - TL8

Weight 4kg empty - capacity 36kg

Price Cr75

Generates 1 Watt per 4.5kg carried while walking. No increase in generation for running or overloading.

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From the story here: In the News

Also check out the P-Battery in the article linked at the bottom

I leave it to someone else to put that to Traveller, for the time being at least

 

[mike wightman]

Clever, what will they think of next?

 

[Fritz_Brown]

The only problem is this is based on people who don't walk properly - at least with a load. My hips don't move up and down that much when I'm running, much less walking. Of course, I actually learned how to march well before I entered the military - in a marching band. (You really have to walk smoothly when you have one of those giant q-tip hats on your head!)

Of course, could this be hooked to those powered exoskeletons we have seen lately? Then you could power the exoskeleton with the motion from the exoskeleton.... Hey, a perpetual motion machine!

 

[Maladominus]

So is this the Traveller version of Bigby's Bag of Infinite Space?

or maybe it was Baby Yaga's Bag of....err... I forgot

 

[mike wightman]

That'll be Baby Yaga's Bag of forgetfulness then

(It was Baga Yaga's Hut...

)

 

[Todg]

Why bother? I figure the 3I has a more enlightened view about nuclear energy. We may soon be able to build safe isotope powered batteries in familiar form factors (say AA) that will last for years.

http://www.betabatt.com

 

[Anthony]

While radioactives aren't the most toxic substances on earth (that honor belongs to some biotoxins), any radioactive capable of generating usable levels of power is enormously toxic -- these batteries may be harmless while intact, but they would be very dangerous if broken apart or crushed.

To be honest, this isn't anything specifically about nuclear power -- anything containing a watt-year of power is dangerous.

 

[Todg]

The first use of the BetaBatt may be in implanted medical devices. From a recent article:

There were a number of practical reasons for selecting tritium as the source of energy, says co-author Larry Gadeken of BetaBatt - particularly safety and containment.

"Tritium emits only low energy beta particles (electrons) that can be shielded by very thin materials, such as a sheet of paper," says Gadeken.

"The hermetically-sealed, metallic BetaBattery cases will encapsulate the entire radioactive energy source, just like a normal battery contains its chemical source so it cannot escape."

Even if the hermetic case were to be breached, adds Gadeken, the source material the team is developing will be a hard plastic that incorporates tritium into its chemical structure. Unlike a chemical paste, the plastic cannot not leak out or leach into the surrounding environment.

[snip]

The structures are robust - tolerant to motion and shock, and functional from -148° Fahrenheit (-100° Celsius) to 302° F (150°C) - and may never have to be changed for the lifetime of the device.

 

[Anthony]

Originally posted by Corejob:

"Tritium emits only low energy beta particles (electrons) that can be shielded by very thin materials, such as a sheet of paper,"

Yes, it has about the same penetration as an alpha source -- which can also be stopped by paper or your skin, but will kill you if it's loose unshielded in your body. I agree that as long as you have shielding, tritium (or any pure alpha source) is not harmful. This is why I was talking about what happens when the battery is crushed (most batteries are somewhat toxic when crushed, but tritium plastic would definately be on the high end of the toxicity scale).

 

[Todg]

I'm not sure why. It is merely the radiation and its uptake in the body that makes Tritium toxic.This is not nerve gas we're taling about. If the tritium is 'incorporated into the chemical structure of the plastic', even crushing it is not going to allow anything to escape. Unless maybe you pick up the pieces, grind them up and eat them. Such a battery is certainly going to be safe enough for use in military applications.

For that matter, betavoltaics are already in use in specialized applications. What is unique about BetaBatt is that it's a much higher powered battery than previously thought possible thanks to better capturing materials. It seem to indicate that betavoltaics will have much wider applications that previously thought.

 

[Anthony]

Originally posted by Corejob:
I'm not sure why. It is merely the radiation and its uptake in the body that makes Tritium toxic.This is not nerve gas we're taling about. If the tritium is 'incorporated into the chemical structure of the plastic', even crushing it is not going to allow anything to escape.

Tritium beta rays have low penetration, but it's not zero. It will escape from small pieces.

 

[Todg]

OK, so what is the exposure danger presuming you don't eat/inhale the stuff? Or even if you do. Any more toxic that DU? Where's the big danger label for my tritium night sights, tritium compass and tritium illuminated watch?

Life is dangerous. Are you more likely to die from exposure to a crushed battery, or a road accident? Can we please quantfy the toxicity, because the numbers I'm reading suggest the danger is pretty darn low.

 

[Anthony]

Originally posted by Corejob:
OK, so what is the exposure danger presuming you don't eat/inhale the stuff? Or even if you do. Any more toxic that DU?

The exposure danger, if you don't eat/inhale it, is pretty much zero. If you do, it really depends on the degree to which the stuff remains chemically stable in the body.

Basically, inhaling anything that glows is not going to be good.

Where's the big danger label for my tritium night sights, tritium compass and tritium illuminated watch?

As long as it's sealed, it's not a risk, but these batteries are using a _lot_ more tritium. Aside from that, I'd be curious about what the disposal rules are for your tritium night sights, compass, and watch are.

 

[Todg]

None that the manufacturer told me about. But my NiCad batteries are carefully labeled that they should be disposed of properly.

Everything is toxic to some degree. Too much water is distinctly unheathy for humans.

Nothing personal, but I had to laugh when I saw you were in Berkeley, a city that bans nuclear weapons (among other things). And I can recall seeing more than one item that is 'known to the state of California' to cause cancer.

But I bet people still get into their cars and drive to work.

 

[Anthony]

I'm aware that Berkeley is somewhat insane about radioactives. I'm not; I'm not even anti-nuclear per se. However, the fact is, a lethal dose of radiation is about 100 milliwatt-hours of power, which means I really don't care for high potency radioactive sources to be carried into situations where they are extremely prone to events that will rupture their shielding.

Other than that, do the ad hominem attacks really help?

 

[Todg]

Not meant to be ad hominem. Just trying to inject a little humor.

Some casual research on the web failed to show any particularly high risk associate with small amounts of tritium or betavoltaics. Without actual numbers, it's hard objectively assign risk.

Since one of the planned uses for these new BetaBatts is in implanted medical devices like pacemakers, it's hard to imagine that the risks are that high. Given the general distrust of anything radioactive by the public at large, it's hard to imagine anyone spending significant sums on R&D on a product that they won't be able to market.

 

[Todg]

Not meant to be ad hominem. Just trying to inject a little humor.

Some casual research on the web failed to show any particularly high risk associate with small amounts of tritium or betavoltaics. Without actual numbers, it's hard objectively assign risk.

Since one of the planned uses for these new BetaBatts is in implanted medical devices like pacemakers, it's hard to imagine that the risks are that high. Given the general distrust of anything radioactive by the public at large, it's hard to imagine anyone spending significant sums on R&D on a product that they won't be able to market.

 

[Anthony]

A tritium power source is certainly safe as long as the tritium remains contained. As most likely ways to release the tritium in an implanted source will give the victim more immediate health problems, it's not really a big problem. My only real concern is for military applications.

Even then, it may be that effects sufficient to release dangerous amounts of tritium are also sufficient to make any health hazards from tritium irrelevant. It's just something I'm not terribly confident about.

BTW, 1 watt of tritium is 9 kilocuries, which is not a small amount.

 

[Todg]

Hmm.

Do you know offhand how ionizing radation converts to electrical energy in something like a Betavoltaic? By that I mean how much radiation is required to produce a certain electrical power output?

Consider a betavoltaic replacement for the common AA 1.5 volt battery. While such batteries typically are rated at anywhere from 1000-2500mAH, it doesn't tell us what the normal operating current is, only the total current capacity at the given voltage.

I'm trying to figure out just how much material we are talking about, and what is the potential hazard in something like a betavoltaic AA cell.

Some data suggest that Beatvoltaics have the potential of as much as 10^7 to 10^8 watt hour per kilogram of radioisotope. Now, I'm not keen on the idea of packing around a kilo of RadioIsotope, but it gives us a starting point.

Going back to the AA battery, lets consider a common military application. Looking at a fairly common 1st genration starlight scope, I see that it has a battery life of 20 hours using 4 AA batteries. Assuming 2000mHA batteries, that works out to be 12 watts in 20 hours, or 600 mW-hours. If we take the figure from above, and assume that it's a linear function, it looks like we need a pretty small aount of radioisotope to generate the requied power. Just how dangerous is this amount?

Natually the above requires a large number of assumtions, but assuming a fairly mature technology in the 3I, do betavoltaics make a resonable replacement for batteries at a reasonable tech?

In other words, without resorting to any major handwavium, can we assume that past a moderate tech level battery life is going to be pretty much a non-issue, at least for low powered devices?

 

[Anthony]

Talking about wH/kg is kind of weird; one of the problems with radioisotope batteries is that you can't turn them off. The initial power output of tritium is slightly over 1W/g, and it will drop by 50% in 12.32 years; for a 1W device you probably want an initial power output of at least 1.5W (and you recycle it when power drops to 1W, which will take about 7 years). Including inefficiency, we're probably talking 2-5g of tritium per watt of power.

I don't quite get your calculations above. Given that 4AA batteries (holding ~10 wH) power it for 20 hours, it has a power draw of 0.5W, and needs a 0.5W power source, or 1-2.5G of tritium. That's definately enough radioactive material to be considered hazardous waste requiring special processing, though if properly handled it won't be a threat. It will also be extremely expensive (the current price for tritium is above $10,000/g).

Within the Traveller setting, nuclear dampers change everything about this:
1) manufacturing of radioisotopes should be appreciably cheaper.
2) use of a nuclear damper can adjust the power output of a radioisotope, allowing using dramatically smaller amounts of isotope, as long as you can also fit the damper components in (the minimum size for dampers is unclear).
3) someone else's nuclear damper can do the same thing. If you have a conventional radioisotope power source, and it gets hit by a nuclear damper tuned to accelerate decay, the power source is likely to be destroyed and may explode violently (a damper-based power source should be less vulnerable). Tune the damper to slow decay and the power source becomes useless, though this is usually less of a problem.