My only connection to the field is that I am a guy who uses zeolites in a redneck way - so take this with a huge heap of salt - but I think this is a three part chicken and egg problem. People don't use MOFs because they're expensive, they're expensive because they're not mass-produced, and they're not mass produced because the shape of the demand is uncertain.
The shape of the demand is the tricky bit. They're not like many other emerging technologies; they are a whole class of materials with wildly different properties, each of which you can produce in several forms; and production is wildly different depending on the type. If there is demand for X tons/yr, spread across 10 industries, but 90% of that demand is in one industry that requires properties of XYZ, then you need to produce the right MOFs in the right form.
The issue, in my mind, is that a lot of this stuff sort of requires a very large vertically integrated company or government project to kickstart it. You can't go out as a company and say "we want to buy X tons of MIL-53(Sc)" [0], nobody would sell it to you. You also can't go out as a producer and start making X tons of MIL-53(Sc) either. The ideal would be that you are, say, TSMC and it would enhance one of your processes, so you make a few kg in house, you use most of it, you sell the rest, and kickstart an industry in that way.
From my perspective - which, again, take with a heap of salt - I think that academia could do their part by "advertising" the most promising candidates better. The list of MOFs is long and many are not usable or stable in real world conditions. Take some of the more promising candidates out of the lab and do some demos with industry. Put together some videos. Write up some honest reports toward an engineer's point of view. That would provide a real boost towards real-world applications.
[0] I just picked MIL-53(Sc) because it's funny, obviously nobody in the real world is going to use scandium in a production product.
There definitely is a bit of chicken-egg going on. But at the same time, if there was a truly emerging market, people would find a way to try and force it.
Right now the main issue is that there aren't even really great, cheap ways to mass produce them. Almost everything that's been performed on MOFs has been at the laboratory scale, and there's not necessarily a clear path to scale up. And there are fundamental cost-to-effect ratio issues that can't necessarily be easily overcome.
The article gives a good simplified explanation, here is my shorter explanation: porous materials, like sponges, have a lot of surface area, which is useful for two main reasons: 1) speeding up reaction rates and 2) capturing and releasing molecules (water, CO2, pollutants, etc.) More surface area is more valuable. Before, the most surface area we had was with zeolites, which are aluminosilicate minerals which occur naturally and are also synthetically produced - the synthetics mostly produced by trial and error. MOFs are unique in a few ways; for one, they are rationally designed molecules where we can predict some properties, and two, the surface area is far higher than zeolites. Zeolites range from 10-1700 m2/gram based on how you measure (most are from 20-400) and MOFs range from 1000-7000+.
Unfortunately MOFs are still quite expensive and very much on the cutting edge, so I am forced to use zeolites anytime I want a lot of surface area, but they are getting more accessible (you can now buy them on Amazon!) and I imagine the price will come down for some of the simpler to make MOFs in the near future.
I've done this before (not indefinitely, but for many trips around the world.)
I agree with the author on a lot: 1) it's not a good way to live long term, 2) traveling with as little as possible completely transforms the traveling experience, 3) zero-bag travel is great, 4) a good quality small bag with well designed compartments is critical, 5) M-series Macs are the only way to go, 6) two thumb drives is very convenient if you're not worried about searches, 7) darn tough socks, 8) first aid with bandaids/antiseptic/mylar blanket, I also include benadryl, ibuprofen and other common OTC meds.
I disagree on: 1) I prefer a 2M USB-C cord over 1M, 2) I have mostly cotton or merino clothes and try not to use any synthetic fabrics, especially no synthetic underwear, 3) I prefer jeans, especially in colder climates and 4) carrying "stuff" on you long term (like a jacket with things in the pockets) can get sort of annoying after a while.
And finally, extra stuff I carry that the author doesn't: separate camera, snacks (mostly nuts), Garmin inReach, handkerchiefs, wired earbuds, flashlight, knife, an eye mask, sometimes a Travelrest pillow, and two sizes of paper notebooks and pens.
- I can't do zero-bag travel, bags are just too convenient. I have at least a little foldable backpack. For example, if I have a jacket, I like the ability to put the jacket inside the bag if the weather calls for it. Or maybe I want to carry a water bottle. Zero-bag means stuffing your pockets, carrying stuff by hand, etc... not very convenient if you ask me.
- I don't really like bags with compartments, I find they get in the way more than they help. Instead, I use a regular bag and put stuff in ziploc bags if I need some organization. It also protects from rain.
- For the USB-C cord, I use 3m, even as an everyday carry. It may seem over the top but sometimes, the power outlet not where you want to plug your phone. For example you may want your phone charging on your nightstand while the socket is on the other side of the bed. 3m lets you cross the bed, 2m doesn't.
- I love synthetic fabrics, dries faster than natural fibers, it is important to me as dry time can be a problem when doing laundry while travelling. Merino wool is great too, but I keep cotton for home.
- Not a fan of jeans during travel, take forever to dry, and they are not that hot for how heavy they are. They make great work clothes (their original purpose), and are relatively fashionable, but during travel when I am not going for style, I use convertible hiking pants.
- I don't travel with a knife, too much of a problem with security. Though I sometimes carry a "swisstech utili-key". It has a blade but it really looks like a key, so it is stealthy. It is unusable as a weapon, but if some overzealous security guy takes it away from you, it is super cheap so it won't be a big loss.
Why no synthetic underwear? I feel like I would be miserable with only cotton boxer-briefs... I sweat entirely too much even in moderate weather to be comfortable in cotton. I am partial to Pair of Thieves extra long boxer-briefs, they don't ride up at all since I have big thighs. When travelling I can wash them in a sink, and they dry way more quickly than cotton.
The replacement for synthetic underwear is wool, not cotton. For weeklong wilderness backpacking trips, I used to vacillate between a fresh pair of synthetic boxer briefs every every day, which took a lot of space, and one for every other day, which was gross. Now I wear a single pair of wool boxer briefs all week, and it feels and smells better at the end of the week than synthetic underwear does after two days. Same for sleeping: I used to bring a couple of pairs of synthetic boxers, and now I'm down to one pair of wool underwear. Two pairs for the entire week, one for days and one for nights.
Granted, wilderness backpacking has completely different standards for smells and grossness, but the comparison carries over to the higher standards of the "front country." In hot, sweaty weather, synthetic underwear gets noticeably grosser and smellier than wool over the course of a day.
Mine are SmartWool brand. According to their web site, they use an 88% wool, 12% nylon blend, but I haven't experienced any odor issues.
I have an older pair that is 100% wool (I don't recall the brand; they might be a very very old SmartWool product) but the lack of stretch makes them less comfortable.
Editing here since my original comment is too old: in a pinch, I've also had much better results washing wool underwear in a hotel bathroom than synthetic underwear. Contrary to their reputation, neither wool nor synthetic underwear dry quickly, even with a hair dryer, but wool dries faster, feels cleaner after washing, and in the worst case scenario is much more comfortable wet than synthetic underwear.
I also feel the same way. I travel with the absolute minimum of synthetic fabric clothing, I have found that by far the best material is wool, especially merino wool, and if that's not an option something that is natural fiber derived modal like bamboo or wood cellulose modal is good. Polyester and other synthetic fabrics repel moisture better, but don't wash by hand or withstand hard wearing as well as natural fibers, and also don't work as well across climates and ecologies.
A layered clothing approach helps a lot. I wear an undershirt (Icebreaker Merino T) every single day, which helps me to regulate my body temperature between hot and cold climates, without requiring a major increase in the amount of clothing I have to bring. The only outerwear I had to bring on my trips was a single wool peacoat and a packable windbreaker/rainjacket. By using layers, I was able to use the same set of clothing between 45C and -25C, across 4 continents with no real trouble.
I also try and avoid synthetic fabrics especially for everyday use. What's your rationale behind it? Asking because I'm not exactly sure why I hold this view, and need some inspiration.
As far as concrete facts go, 1) we know that plastic fabrics (polyester, nylon, etc) generate airborne plastic particles which we then breathe in, 2) they exacerbate certain skin conditions, 3) they start to stink much faster than natural fibers, 4) they burn incredibly fast and fuse to your skin and 5) they’re funding the oil industry. Those factors alone are enough for me to essentially ban them from my body.
Beyond facts, there is also a certain ugly vibe to plastic clothes. They’re cheap and impersonal and disposable and typically generic. I have never really fallen in love with a polyester product. When it came time to throw away my polyester clothes, I wasn’t surprised to find that everything I really loved was wool/cotton/silk.
There's a funny comment downthread that says "It's like the backyard furnaces during the Great Leap Forward."
Everyone replying disagrees, but I think it's a perfect analogy: just like the backyard furnaces, these small-scale installations are inefficient, provide a negligible portion of total energy needs (<1% of total energy needs if everyone in Germany did it, from TFA), look ugly and - this is the most important - provide the feeling of doing something about a serious problem without actually doing anything substantial.
Actually, it is pretty common for homeowners to first install a balcony solar power plant and eventually "upgrading" to a full-scale solar power installation on the roof. The first is very easy and cheap to do and can be done on a weekend, the latter is costly, requires dealing with bureaucracy and partially-sleazy system sellers, and thus requires overcoming way more substantial hurdles, for which one must muster the motivation first.
Balcony solar power plants are sort of a gateway drug into actual, practical participation in the renewable energy sector. They are easy to install, cheap, have a clear and fast way to profitability, and provide significant gamification value (people who buy these kits tend to start with constantly monitoring their energy generation and usage in apps afterwards). That "ice breaker" effect should not be underestimated. It can pave the way to way more substantial actions (or to the acceptance of actions taken by others) that people wouldn't have considered otherwise simply due to inertia of the status quo.
> look ugly
That is YOUR taste. I consider most balconies with solar panels to look futuristic and cool. Garden houses with solar panels on the roof also look way cooler and more modern than without them.
> provide the feeling of doing something about a serious problem without actually doing anything substantial.
You're wrong about this. There are a lot of people who still think solar power is only about environmental virtue-signalling and it can never compete with good old dinosaur juice. If everyone adopts balcony solar, it'll help convince these people they're wrong. At least the ones who are merely misinformed rather than dug into an ideology.
And yes, 1% of German energy is a ton of energy; but that is an incredibly optimistic forecast of if _every_ German did this. There are 85 million Germans; they could do a lot of things with their combined efforts. Backyard furnaces produced millions of tons of steel; seems like a very apt comparison.
I actually have solar of my own. It powered my entire life (off grid!) for years. That still doesn't mean I think individual small-scale solar is a meaningful solution to the climate crisis.
The biggest risk around climate, in my opinion, is the risk that people and governments think "we're doing something" when they are not. In this case, balcony solar has a very short payback time (a claimed 5 years for one guy's install! That is preposterously short for any investment!) because of the strange way that residential power is priced. If people really paid for the power and the grid infrastructure in relation to the real costs, balcony solar would never pay itself back, but essentially nobody understands that. Instead, they see the large amount they're saving and mentally that magnifies the impact of what they're doing. From the various posts I found, an ideal, un-shaded install produces between 200 and 500 kWh per year, depending on orientation and size. Obviously any sort of shading would drop that off a cliff. Compare that with the 38 MWh (38,000 kWh) per year of primary energy that the average German consumes...
Your total energy needs figure today is completely irrelevant. Half of the so called needs are just for entertainment. Now excuse me I have to step in my SUV and drive to lake Garda Italy for the weekend at 200 km/h.
The GP comment is technically correct, if somewhat incomplete. A 40 m3 room (about 14’x14’x8’) has about 50kg of air in it; that’s only ~300 Wh to heat every molecule of it by an entire 20C. The thermal mass of the other things is orders of magnitude larger.
The reason that I consider that explanation somewhat incomplete is the behavior of the air and the embodied energy. Imagine it’s winter, the exterior air is quite dry, and you open a window. You will easily lose a large amount of moisture, making the air uncomfortably dry. So you turn on a humidifier, but that will cool the room further with the evaporation of water. You also have to consider convective heat transfer. The fast-moving air is quite good at transferring heat to the outdoors. So, even if you don’t care about humidity, you will lose a lot of heat through convection.
But yes, strictly speaking, the thermal mass of the air is very low in most structures and situations.
I've got one laptop case where it is quite spongy with panels like neoprene and some stretch fabric. When I ride about half an hour with a driver who is not smoking but had smoked in the vehicle (supposed to be always with the windows open out of courtesy to the other drivers), the next morning when I pick up the laptop it smells like tobacco and it takes a few days to go away. This doesn't happen with the backpack which is not built like that.
You can also take the domestic calculations further.
If you have 50 kilos of dead weight for instance, whether it's a set of workout weights or a piece of furniture, and it's all a stable 10 degrees C through and through, it's going to take 50 kilos of 30 C warm air constantly coming into intimate contact with the dead weight however long it takes before your dead weight gets to 20 C and the air does too.
That can be a whole lot longer without forced air. But it still takes 50 kilos of air no matter what.
>the thermal mass of the air is very low
This is exactly it, along with heat exchange capacity.
If you pull out the water hose you could spray it down with 50 kilos of water in no time, but not everybody's living room can withstand that :)
Now if you had 500 kilos of 20 C furniture along with everything else, and you opened your windows and let out the full 50 kilos of air which was fully replaced by 0 C air, then shut the window to achieve a closed system once again, you'd still be sitting on 20C furniture for some time and only breathing 0C air for a short period before the overwhelming mass of the furniture itself warmed the much lesser mass of air right back up a few degrees, and to about 18 C eventually. Which none of the other heated mass will drop below.
With no additional heat added, assuming insulation was perfect, but that's the number of degrees lost from one single full air exchange alone under those conditions.
While the windows are open is the time to vacuum the carpets, drapes and furniture so you can get some forced air through them and let absorbed irritants out instead of just stir it up and move it around. The high-surface-area porous materials can soak up more than you think.
Air exchange matters again because some of the irritants are not the kind that evaporate or "dissolve in air" very fast, and they might have had all kinds of continuous time to accumulate.
You've got to figure that curtains can hold grams of unwanted stuff in their pores from previous bad air days, furniture ounces & carpets pounds plus a lot of the latter is solids which may give off odors or stir up allergens for quite some time once it has gotten into the pores and other tortuous passages. That's a lot of air exchange when you do the math.
Change your air filter after stirring things up and breathe easier after that :)
Interesting, but I use a much more powerful germicidal UV source. Because of the power requirements it uses a fusion energy source located ~150M km away. (sunlight in fresh air.)
In fairness to the article, ventilation was mentioned, but also quickly dismissed. The 60% efficiency figure quoted for ERV is also a bit on the low side for many contexts. And sure, ERV fans themselves use some power (say 50W) but that's about what you'd use in a decent size room with some UV lamps and a fan.
This is a phenomenal article. It is interesting even if you have no interest in war. There are countless scattered insights about culture, pedagogy, leadership, personal relationships, secrecy and others.
The insights on pedagogy are some of the most interesting. The main problems, according to the author, are on-high lectures where instructors are not challenged, a lack of inter-student competition, insistence on both students and instructors saving face by not knowing the answer, and a culture of secrecy.
Other interesting issues: cohesion between officers and enlisted, being honest about your faults, taking responsibility. A lot of these lessons, I think, could be applied quite broadly (war, education, business, personal relationships, etc.)
Wow, this is a terrible interview. The interviewer repeatedly references his book Inferno. I like the Telegraph review of it, "Don't Make Fun of Renowned Dan Brown", available here sans paywall: https://onehundredpages.wordpress.com/2013/06/12/dont-make-f...
Most inventions related to music, food, clothing, children, entertainment, art, medicine, architecture...
Hm, strange. That has been allowed for many years now, you do pay a fee of 10 euros though. There are no restrictions on where you can ride the bikes either.
I see several comments here that misunderstand "perovskites", so to be clear: "perovskite" can refer to either the mineral or the crystal structures with the same structure as the mineral. Virtually everything written about "perovskites" refers to perovskite structures; the actual mineral perovskite is just used as a rock (geologists poke at it and miners crush it up.)
Perovskite structures are interesting because they have unique material properties. The range of properties is quite broad: ferroelectric, pyroelectric, and piezoelectric properties, photoelasticity, very high permittivity, et cetera. In popular science news, you will mostly read about potential uses in solar cells, but they are already commonly used in our world: barium titanate is used as a dielectric in capacitors, lead zirconium titanate is used as the piezoelectric crystal in many resonators, lithium niobate is used for optical waveguides and for optical antialiasing filters because of its birefringence.
The shape of the demand is the tricky bit. They're not like many other emerging technologies; they are a whole class of materials with wildly different properties, each of which you can produce in several forms; and production is wildly different depending on the type. If there is demand for X tons/yr, spread across 10 industries, but 90% of that demand is in one industry that requires properties of XYZ, then you need to produce the right MOFs in the right form.
The issue, in my mind, is that a lot of this stuff sort of requires a very large vertically integrated company or government project to kickstart it. You can't go out as a company and say "we want to buy X tons of MIL-53(Sc)" [0], nobody would sell it to you. You also can't go out as a producer and start making X tons of MIL-53(Sc) either. The ideal would be that you are, say, TSMC and it would enhance one of your processes, so you make a few kg in house, you use most of it, you sell the rest, and kickstart an industry in that way.
From my perspective - which, again, take with a heap of salt - I think that academia could do their part by "advertising" the most promising candidates better. The list of MOFs is long and many are not usable or stable in real world conditions. Take some of the more promising candidates out of the lab and do some demos with industry. Put together some videos. Write up some honest reports toward an engineer's point of view. That would provide a real boost towards real-world applications.
[0] I just picked MIL-53(Sc) because it's funny, obviously nobody in the real world is going to use scandium in a production product.
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