Tuesday Tech Links

Oscar Gordon

A Navy Turbine Tech who learned to spin wrenches on old cars, Oscar has since been trained as an Engineer & Software Developer & now writes tools for other engineers. When not in his shop or at work, he can be found spending time with his family, gardening, hiking, kayaking, gaming, or whatever strikes his fancy & fits in the budget.

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63 Responses

  1. Brandon Berg says:

    Isn’t “reverse osmosis” just a fancy way of saying pushing water through a very fine filter? Why is this expensive?Report

  2. Smart Bricks

    Does Jethro Tull know about this?Report

  3. Kimmi says:

    I cook. Moderate levels of pepper spray are expected while making stir fry.Report

  4. Damon says:

    Regarding the pepper spray pistol: how is this any different from pepper spray in a “spray container”, other than the mechanism and the range? I mean, sure, if you wanted to use this at 200 feet you could, but I doubt that that’s the range you’re defending yourself. At that range, you can run away yes?

    And what about that lingering cloud? Not sure I want that lingering in my house in a defensive use situation. Does this crap get absorbed by sheet rock or carpets. What about residue being harmful to pets?Report

    • Kimmi in reply to Damon says:

      Often, with nonlethals, the idea is to impede pursuit.
      I haven’t noticed any capsacin issues, and I use it frequently in the kitchen where it does turn into an aerosol that moderately impedes breathing (nose irritation) and occasionally eyesight.Report

    • Marchmaine in reply to Damon says:

      My bigger concern would be the CO2 delivery system failure. CO2 canisters leak when stored for long periods. Like the concept, not sold on the delivery.Report

      • DensityDuck in reply to Marchmaine says:

        How long is “long” and how leak is “leak”?

        And if you’re paying $400 for this thing, versus a $10 fill-up bottle from the local paintball shop, you might expect a rather lower leak rate.Report

        • Marchmaine in reply to DensityDuck says:

          Nevermind… they acknowledge the issue and have engineered around it:

          Unlike most air powered guns, you can keep a Salt gun loaded with an unused CO2 cartridge indefinitely. We have a proprietary patent on our Salt gun which allows the CO2 cartridge to stay sealed, and in the gun, until it is needed. Upon the first pull of the trigger in the Salt gun, the CO2 cartridge will be penetrated, and the second pull will then release a round. This leaves the product ready for use as soon as you need it without any hassle – which is key during a home invasion. Once penetrated on the first pull, the CO2 cartridge will last 24 hours or 21 shots.

          It does present a lower order concern that never having fired that canister, there’s some increase in risk that a malfunction might occur (sometimes the tapping of the canister doesn’t go well, it doesn’t seal, or its (very rarely) undergassed, or some other malfunction.).

          Ultimately, I’d prefer the propellant be part of the bullet… a bad bullet can be discharged, a failed unit is a failed unit.Report

          • Oscar Gordon in reply to Marchmaine says:

            Discharging a squib round requires a ram rod, and I bet squib rounds are probably as common as empty CO2 canisters.

            Let’s not let the perfect be the enemy of the good. As I said in my post a few months back, something like this is for people who want a device that is more effective than a single shot Taser or a can of spray, but are uncomfortable with firearms for whatever reason.Report

    • DensityDuck in reply to Damon says:

      Containing the pepper spray in a pellet until impact reduces the chance that it’ll blow back into the user’s face due to air-conditioning (or simple bad aim.) It also allows the deterrent to be deployed at a greater distance, so that your attacker can’t just bum-rush you and tank the spray until they grab you.Report

      • Damon in reply to DensityDuck says:

        I agree on the concept of a longer distance self defense non lethal device, I just don’t see how useful it would be inside a building, like a home. I would have more/better application on the street, but I think there people would get all confuse-y on whether the item was a real pistol or not, like cops. Might get you shot carrying one of these things around. I would also suspect that carrying it concealed would be illegal. Maybe not.Report

        • Kimmi in reply to Damon says:

          Guns aren’t terribly useful inside a home either. Too much clutter and cover.
          Much better to simply use some steel doors (for common criminals).Report

          • Damon in reply to Kimmi says:

            We’ll have to agree to disagree.

            If someone has breached my steel door, I want a lethal or fully incapacitating non lethal device to use as a final resort. And I much prefer the “empty the mag into the body, reload, and put two in the head” type of device.Report

            • Kimmi in reply to Damon says:

              I take it the people most likely to be after you aren’t like to use gas?
              I mean, seriously, this isn’t too hard, particularly if you’re sleeping. Pipe in some carbon monoxide or something…

              Guns work. Pretty well, if you’re conscious, have clear line of sight, and know where your enemies are. [hence why I favor them for rural areas where cops are not terribly reliable. ’round here it’s 5 minutes from home to hospital, and the cops aren’t that much slower].

              Or, you could invest in a cell phone, and a ladder to get the hell down and away from the idiot who broke through your steel door.Report

              • Damon in reply to Kimmi says:

                “I take it the people most likely to be after you aren’t like to use gas?” No, I don’t expect that.

                It wouldn’t make sense to exit via a ladder. I’d end up very near the front door and would probably be noticed. I have a cell phone, and I’m in a suburban environment, but the cops are still 5 mins away. Long enough to get kilt.Report

            • David Parsons in reply to Damon says:

              If someone is attacking you and has the horsepower to break down the door to your panic room, I /strongly/ suspect that anything other than a neighborhood nuclear deterrent will be the moral equivalent of mooning an oncoming freight train. I’m not going to try and stop you from gun fondling, but if you’ve got that sort of enemy maybe you should consider moving closer to the police station or beefing up your panic room so that the local SWAT team can get to you before your foes can break in?Report

              • Damon in reply to David Parsons says:

                My steel door is located right next to a big pane of glass–you know, the front door. (I don’t know where you got the idea I have a panic room.) If crooks are coming in, that’s how they are coming in….or they are cutting the glass and unlatching the bolt. The house cannot be modified to any major degree for various reasons I don’t care to disclose.

                I don’t know what kind of enemy you think I think I have. I’m talking about criminals, not some mercenary extraction team sent from Russia or such.

                I’m glad you endorse my right to possess and use small tactical nukes. And please understand I don’t fondle guns. Women yes, but only with their permission. Fondling firearms is like fondling a hammer. Not fun. But it seems that the anti gun folk think that’s all gun owners do…sit around and molest their guns. I assure they don’t.Report

              • David Parsons in reply to Damon says:

                Burglars, as a general rule, just want to take the 5-finger discount and get out without fuss. You being there, gun or ungunned, disturbs their peaceful routine of breaking and entering and will keep them away.
                (The only time I was ever robbed — twice, actually, though they didn’t get anything the second time — was when I was living in a flat that was so laughably insecure that it might as well have had rubber bands keeping the doors closed, but despite that and living in Chicago the burglers waited until I wasn’t around before taking my CD collection and stereo. If I had a gun to “protect myself”, well, that’s just something else that the burglers would have walked away with because no I’m not stupid enough to carry at work.)

                My grandfather, who was an impressive gun fondler in the days long before the NRA because a Republican lobbying organization, kept his huge collection of longarms (and a few handguns, for completeness’s sake) in gun cabinets in his study, which was at the opposite end of the house from his bedroom. He was a strong believer in the security advantage of being around, and avoided being robbed (Lyndon LaRouche was born about 2 miles up the street, so he wins the shady white neighborhood award) for his entire live, until he grew infirm, moved into a nursing home, and let my father sell his gun collection.

                So, yeah, your complaints about needing lethal force to defend yourself against burglars are not really a very compelling argument. Pepper pellet guns, water balloons full of fluorescent green paint, or a decorative paper fan would be just as useful, because what will scare the burglers away is you just being there.Report

              • Damon in reply to David Parsons says:

                Yes, robbers generally prefer to wait until folks are gone to rob places, in the US. Why? The higher preponderance of firearms. In the UK, it’s different, as the crooks know the residents are unarmed.

                And I’m not complaining that I need a firearm to defend myself. I have chosen to use one. You are free to disagree and/or not use one. Frankly I don’t care. What I do care about is people thinking that they should/do have the right to limit my choices in how / if I choose to defend myself.Report

        • Oscar Gordon in reply to Damon says:

          In my house, the family sleeps upstairs. If I get an intruder, and I can keep them downstairs by making the bottom of the stairs toxic, I keep my family safe until the cops arrive, or until I can get a gun out of the lockbox.

          Again, this isn’t for everyone, it’s just possibly a better option than a can of mace for some people.Report

          • Damon in reply to Oscar Gordon says:

            Oh, I agree. I think it’s marginally better the a spray can.Report

            • Oscar Gordon in reply to Damon says:

              Since I don’t own one, I can’t give an informed opinion, but I’d say it’s better than marginal.

              Now, what I’d do is start making other pellets, perhaps ones loaded with the irritant in an oil base. I’d buy that, because then I’d just paint the landing at the bottom of the stairs with the first magazine. Oil, hardwood floor, good luck finding traction while I hammer you with the second mag.

              Also, oil could be better for close range self defense.Report

          • Kimmi in reply to Oscar Gordon says:

            Steel door mostly does the same thing, at least for thieves and what not. “dude, you really don’t want to come up here. Also, hear me, I’m calling the police”Report

    • Oscar Gordon in reply to Damon says:

      It’s a powder, so absorption is probably low. A lot less than blood, at any rate.Report

    • dragonfrog in reply to Damon says:

      I figure if you’ve had to defend yourself from an intruder in your home, replacing the carpets is a minor concern. I’d probably have to replace the spot where I’d peed myself anyway.

      More generally though, I think a realistic solution to the firearms issue in the US is not going to be about replacing one kind of anti-personnel weapon with another, but more about addressing the mentality that it’s keeping anti-personnel weapons around the house is a sensible precaution; that somehow if you shoot an intruder you will be one of the minority who shoots an actual intruder, and not one of the majority who shoots a houseguest or your own child sneaking home late.Report

      • Kimmi in reply to dragonfrog says:

        If you don’t have clear line of sight, don’t shoot the fucking moving target.
        Shoot the lights. They’re stationary, and if you’re both blind — you know your house better than the other guy.

        Guns are a fine idea in rural areas where the cops are hours out. And you’ve got enough line of sight to find someone stupid enough to drive up to hassle you.Report

        • dragonfrog in reply to Kimmi says:

          Guns are perhaps a fine idea in rural areas of Honduras and Jamaica, where invasions of one’s walled compound are a statistically significant concern.

          They are a terrible idea in rural areas of Iceland or Japan, which have homicide rates so close to zero it might as well be zero.

          Somewhere in the middle is a gray area where it’s not clear if your safer with or without a gun – but given the rates of accidental vs self-defense shootings in the US (not to mention domestic disputes that wouldn’t have turned into homicides if there hadn’t been a gun in the home) it’s pretty clear the US is well into “safer without a gun” territory.Report

          • Damon in reply to dragonfrog says:

            It’s also common sense that cars are safer doing 30 mph everywhere vs the current posted speed limits, but our society seems to be able to cope with more risk / higher speeds. I see no difference with firearms and more compelling reasons to keep other people’s opinions about what to I should own/keep in my house limited.Report

            • dragonfrog in reply to Damon says:

              It’s not exactly analogous though – higher speeds get you to your destination faster, with the cost being a higher risk that your destination will be suddenly redirected to the emergency ward or morgue. A reward, balanced by an increase in risk.

              If guns for self defence in fact keep one safer or have some other quantifiable benefit then the risk tradeoff would seem more comparable – but statistics suggest that American gun owners on the whole are most likely to kill themselves, followed by someone else they didn’t mean to shoot, followed only in third likelihood by someone else they did mean to shoot.

              Note, I’m not here to take your gun away. I just question your risk management arithmetic.Report

          • Kimmi in reply to dragonfrog says:

            And argentina? (this is a reference to how quickly things can go to shit in normally decent places) Please tell me what you REALLY think about Iceland’s two hour riot (it then got dark. people went home).

            I don’t trust Japan’s homicide statistics, in tokyo or outside of it. They’re notoriously … bad about labeling homicides suicides.Report

      • Oscar Gordon in reply to dragonfrog says:

        if you shoot an intruder you will be one of the minority who shoots an actual intruder, and not one of the majority who shoots a houseguest or your own child sneaking home late.

        Stats needed (I doubt you could claim that a majority of shootings where the homeowner thought s/he was defending themselves actually involve the person shot being a guest or household member; I know it happens, but I think it’s more uncommon than shooting an actual intruder).Report

        • Kimmi in reply to Oscar Gordon says:

          Depends on whether you expect your kid to come home through the window often, I suppose.

          I find it vastly more likely that most people who have a gun won’t be able to get to it, and the ammo and actually defend their house. [Ditto for women who put a gun in their purse, unless the purse was designed for that in mind]Report

        • dragonfrog in reply to Oscar Gordon says:

          There’s http://www.ncbi.nlm.nih.gov/pubmed/9715182

          Granted their “unintentional shootings” probably include mostly things like “gun went off by accident”

          The mistaken identity shootings are somewhat harder to come by it seems.

          • dragonfrog in reply to dragonfrog says:

            I suppose it’s also possible some of the mistaken identity cases were actually homicides against family members where the murderer got the police or jury to believe their excuse that it was mistaken identity…Report

            • Oscar Gordon in reply to dragonfrog says:

              So it’s a hard value to flush out.

              Regardless, would you rather be shot with bullets, or just incapacitated? Likewise, would you rather put holes in someone, or just makes their mucus membranes go into overdrive and spike their pain receptors for a little while? If the idea of critically wounding or killing someone causes you to lose sleep, but you are still anxious about having to rely on police, this kind of thing is a probably a decent alternative.

              Likewise, if you are a person who can not own a firearm, this is probably still legal for you to own.

              I’d rather not play the game of, “That person doesn’t really need to worry about self defense”, because once we start playing it, we can play it across other topics we’d probably rather not.Report

            • Joe Sal in reply to dragonfrog says:

              df, what do you see as the down side to the salt gun? If it displaces a potential lethal discharge for non-lethal one that is useful right?Report

              • dragonfrog in reply to Joe Sal says:

                I don’t think it has any very serious downside. I just don’t think it has much upside either.

                That’s because I don’t think it will see very much uptake. I suspect that a major root of the problem, which this weapon does not address (and any advertising for it will likely contribute to, if only in a very small way) is a general feeling of fear of violence out of all proportion to actual threat levels, and a belief that the best way to reduce one’s risk of violent mishap is to carry anti-personnel weapons and/or keep them in one’s home. And as long as that fear and that belief are prevalent in the US, Americans are mostly going to keep guns, not any other weapon.

                That’s assuming that you see the rates at which Americans keep guns conveniently close with which to shoot themselves and one another as a problem, which obviously not everyone does.Report

              • Joe Sal in reply to dragonfrog says:

                What do you see as rational for a personal means of protection at existing threat levels? Not being flippant, I really would like to know.

                I mean this in the context of not calling on the police, or depending on something outside of ones personal abilities.Report

              • dragonfrog in reply to Joe Sal says:

                Generally if I felt unsafe I’d go for good quality doors, locks, and barred windows first. Maybe a surveillance system.

                It would very much depend on individual circumstance, I think. Not country, city, neighbourhood level, but specific individual level – do you have an estranged ex with a history of violence, a sibling involved in drug trafficking…

                It would have to be some kind of extreme situation before I went to weapons, and then I’d stick with something like bear spray. I’d consider a gun to have an increased risk of suicide and accidental harm to myself and my family that would far outweigh any increase in self-protective safety I might achieve.

                And I think that would apply in most situations I can think of – the greater the surrounding violence rate, the greater the personal stress, so I’d consider the suicide risk to rise along with, and remain more salient to me than, the risk of externally sourced violence, at almost any level.Report

              • Oscar Gordon in reply to dragonfrog says:

                Alright, you recognize that all of this is highly dependant upon individual circumstance, that’s where we start. Everyone has different needs based upon both their actual security needs, and what the risk they perceive and feel comfortable addressing is. Don’t be like Kimmie and make blanket statements.

                If a person has placed all of their personal security needs in having a gun at hand, they are likely a fool. Every security system has layers, some simple, some extreme. This is just one option for any person’s personal security suite. I applaud it because it offers something (IMHO) more effective than pepper spray, but less lethal than a gun. It fills a niche that has long been open.

                I also applaud it because tools like this can serve to displace firearms for two reasons:

                1) Firearms are dangerous and have very little tolerance for error. Most decent, thinking people understand this and, if given a less dangerous option that works, will migrate toward it.

                2) Shooting a firearm well is a perishable skill. If you are not spending the time & money to practice regularly, you are not going to shoot well (and shooting well when in flight/fight is already tough for practiced shooters). Having people with guns, who at best put it in a lockbox and maybe shoot a box of ammo once a year, is dangerous (ask any PD who doesn’t demand their officers train). Something like this can forgive a lot of proficiency sins.

                and then I’d stick with something like bear spray

                PS How is this different from a can of chemical spray?Report

              • Joe Sal in reply to Oscar Gordon says:

                I like the bear spray also and carry a can of it when I go into sketchy areas.Report

              • dragonfrog in reply to Oscar Gordon says:

                It’s not different – bear spray is the commonly available form of capsaicin spray around here.

                I have never in fact felt the need to actually have the stuff. Once I bartended for a night where there was a can of it under the counter. Made me paranoid to have it around is all it achieved.Report

              • Oscar Gordon in reply to dragonfrog says:

                Made me paranoid to have it around is all it achieved.

                Which is a pretty good indicator that you probably shouldn’t bother keeping weapons handy, and find other ways to satisfy your security concerns. But understand that not everyone feels that way. I have a big can of bear spray behind my night stand, doesn’t bother me a wink.

                but more about addressing the mentality that it’s keeping anti-personnel weapons around the house is a sensible precaution

                This is where the issue lies. Not that people want to keep weapons in the house, but that there is a range of comfort with weapons. Some folks are very uncomfortable with them (like you), some are way too comfortable with them, and most folks fall in the middle in varying degrees. The heat comes from the extremes who have decided their way is the only way, and like to get into shouting matches about it and try to pass laws mandating it.Report

              • Joe Sal in reply to dragonfrog says:

                Is there a reason the bear spray made you paranoid to have it around?Report

              • Joe Sal in reply to dragonfrog says:

                That’s a pretty rational answer, thanks for sharing.Report

      • Damon in reply to dragonfrog says:

        Well given the number of people that live in my house, that being 1, anyone else in the house is either invited in or not. Those invited in are sleeping in the same location as I am. Those not, well…..

        @kimmi downthread…”I find it vastly more likely that most people who have a gun won’t be able to get to it, and the ammo and actually defend their house.” That’s why you keep the weapon loaded with spare ammo right next to it. (you choice on whether or not you keep the safety on or not)Report

        • Kimmi in reply to Damon says:

          I assume most people with guns have kids, or may have other (possibly unsupervised) people in the house.

          It’s fine if you have a gun, and wake up easy. (why do i assume people will probably be asleep? Because darkness makes great cover for all sorts of nefarious things).Report

          • Damon in reply to Kimmi says:

            I tend not to worry about 1) other people-they are adults after all, 2) other people’s kids-they are OTHER people’s kids, who should be, you know, parenting.

            A friend of mine owns guns and has a wife and kid. He uses them for self defense, and keeps them locked up, loaded, close by. Being smart about how you handle firearms, and teaching everyone in the house how to handle them safely is important. I took official gun safety when I was 8 or 9, but I was educated by my father long before that and knew how to handle them at 7 or earlier.Report

  5. Marchmaine says:

    “This is a novel application for MFC modules to be made into actuating building blocks as part of wall structures. This will allow us to explore the possibility of treating household waste, generating useful levels of electricity, and have ‘active programmable’ walls within our living environments.”

    On the smart bricks, my first thought was why not line my septic tank with them, or possibly a grey water delivery line and holding tank? Is it a surface area issue? Otherwise, why route my sewage through my walls?

    Then again, I also wish Grey water systems were legal… they aren’t by code where we live.Report

  6. J_A says:

    The MoS2 membrane

    I would have to see the math, but I find the power claims very difficult to believe. Particularly because there is no mention of the rate at which ions traverse the membrane to understand the volumes of water involved in the process.

    A one MW membrane means that every second you are harvesting from a one sq mt (10 sq ft) membrane one MegaJoule of energy, enough to lift one Kg (2.2 pounds) slighly over 100 km (62 miles). It’s the energy contained in eight gallons of gasoline, EVERY SECOND, EVERY TEN SQUARE FEET (sorry, I’m excited).

    Either the three molecules thick membrane manufacturing is extremely costly, no matter how abundant MoS2 is, or the process cannot be scaled up to the 1 m2 area, or limitless energy has arrived to the world.Report

    • Oscar Gordon in reply to J_A says:

      Agree, which is why I called them out specifically.Report

    • Michael Cain in reply to J_A says:

      Or any number of other engineering problems. A membrane three atoms thick is going to require scaffolding to support it (unless, in addition to providing limitless energy, the stuff also has tensile strength that makes carbon nanotubes look fragile). The scaffolding is going to have to be porous enough to allow water contact with the membrane with minimal restriction on flow rate, and not interact with the membrane or the transported ions. It has to be resistant to fouling by any other junk that happens to be in the water. I suspect that the scaffolding will be a significant limiting factor to how much power can be produced.Report

      • J_A in reply to Michael Cain says:

        That’s a good reason to believe it’s not scalable.

        As a reference, solar (rule of thumb) requires 10,000 sq mts (one hectare) per MW. This technology would be 10,000 times more effective area wise.Report

      • Oscar Gordon in reply to Michael Cain says:

        They did say it was a projected value, which means they haven’t actually created 1 m^2 of the stuff and tested it.

        The important question is, if actually deployed, could it produce enough power at some degree of degradation from the theoretical max to have value? I mean, solar power can, theoretically, capture around a MW / m^2 if PV cells were something like 90% efficient at converting photons to electrons (more that a MW in some areas).Report

        • So far as I can tell from reading descriptions at other sites, they’ve created exactly two pores, and extrapolated from that :^) Given the pore size, and their 30% of a m^2 figure, would require ~10^21 pores. Something other than the laser drilling they used would be necessary.

          Solar irradiance in space at Earth’s mean orbital distance is about 1.36 kW/m^2. On the surface, under all that pesky air, something under one kW/m^2 at best. Not MW. Even at Mercury’s orbit total solar irradiation is about 9.1 kW/m^2.Report

  7. J_A says:


    You are off by a factor of 1,000. Solar irradiance in the upper atmosphere is 1.4 kW/m^2. At ground level is 1.0 kW/m^2 (a unit called a Sun 🙂 ). Current PV technology captures 10-15% of it depending on site/ tilting or not, etc. the membranes would produce 1,000 times more.

    If it could be done at 500 times the cost of solar power it would be a revolution. The fact that it’s not being talked about probably means that it is not scalable with current technology.Report

    • Oscar Gordon in reply to J_A says:

      Sorry, I missed the note in the map I was looking at that stated the values shown were annual.Report

      • J_A in reply to Oscar Gordon says:

        1.362 kW/m^2 (I rounded up to 1,4) is the average irradiation on an annual basis in the upper atmosphere. Variation is related to the variations in the earth/Sun distance. There must be a typo in the doc you were reading. Watts (Power) is an instantaneous reading, like HP, not a time based reading like Joules, kWh or BTUReport