"All measurements were performed at 20° ± 0.2°C maintained by an air circulation system unless otherwise noted. The temperature of the films was controlled using a heating/cooling unit (THMS350V, Linkam Scientific Instruments, Salfords, UK) when necessary."
So the latent heat is conducted away by the cooling apparatus, it's just not explicitly stated, to sound more sensational.
Another part from the paper that a lot of people here seem to be ignoring: "Specifically, macroscopic water droplets isothermally form when the NP size is ≤22 nm, RH is >~90%, and ϕPE ranges from 0.05 to 0.35." and "Initial water droplets that are observable under optical microscopy (~1 μm in size) appear within a few seconds after being exposed to 97% RH."
This is really moist air that's only barely short of forming dew. A lot of people are focusing on sensational "violation of physics", when it's an incremental improvement on process that happens naturally.
I think the interesting bit is less about "breaking physics" and more about how finely tuned the material is to encourage this behavior without external cooling.
Keeping the temperature constant with a thermostat is not an issue here. That would only explain things if the surface were kept cooler than the surrounding air (below the dew point), but from the description in the paper that does not seem to be the case. They basically claim that macroscopic droplets form spontaneously from an unsaturated vapor. And no, this is not something permitted by the second law of thermodynamics.
> And no, this is not something permitted by the second law of thermodynamics.
If someone points out to you that your pet theory of the universe is in disagreement with Maxwell’s equations—then so much the worse for Maxwell’s equations. If it is found to be contradicted by observation—well these experimentalists do bungle things sometimes. But if your theory is found to be against the second law of thermodynamics I can give you no hope; there is nothing for it but to collapse in deepest humiliation.
While I generally agree that it sounds dubious, this argument depends on whether the entropy of the liquid in the pore is lower than the entropy of the vapor in the air in the pore. I could see a highly hydrophilic capillary restricting a vapor enough to where it has better entropy in a liquid state.
If that's true we just need to balance energy, which the cooler does.
> I could see a highly hydrophilic capillary restricting a vapor enough to where it has better entropy in a liquid state.
My other comment here (and and a reply to a similar question) has more detail [1], but in short: this is true for capillaries and pores, it is not true for "collectable" droplets on a flat surface.
Practically it just means that the energy to form the droplets is coming from somewhere else, just not via cooling the surface below the dew point. For instance, you could imagine something like squeezing a material that undergoes capillary condensation to get the water out, since you'd pay the requisite energy cost via mechanical work.
Ah that seems to explain it to me, if instead of presenting it as breaking some physics they should have said what actually makes it useful.
My understanding of it now is that since it can work at a higher temperature in an environment where the ambient temperature is low enough the latent heat can be passively radiated away. Even if using an active heat pump the higher temperatures would allow for a more efficient process. A closed system would eventually reach an equilibrium but there is no need to maintain a closed system.
I think the work stands out anyway. Unlike adsorption techniques there is zero change to the mechanism which just keeps pulling water from the air. Presumably, they will put a layer of this material on aluminum to conduct the latent heat and have something that just produces water full time, without additional energy input. consider a 'cube' of fins of this stuff sitting in shade with a collection bucket underneath it. It will be interesting when they build something like that how many liters/day it can extract from ambient air and under what conditions.
Devices like that would be essential during 'wet bulb' days where the temperature and water content of the air created dangerous conditions for people. A passive device that takes no energy and just sucks water out of the air? Could be a lifesaver.
You didn't read the paper did you :-). First, it isn't a "condenser" (which is kind of the cool science here) it is more of a molecular sieve that exploits two materials (one that repels, and one that attracts) the molecule in question (water). The water vapor is "forced[1]" together by the nano-structure, which result in a phase change (vapor to water) and that phase change releases heat into the nano-structure (and pushes the liquid water out to the surface) which makes the nano-structure warmer than the ambient temperature. The aluminum conducts that heat and is convectively radiating it into air on surfaces not covered with the nano-structure.
The researchers also noted that the water that was expressed to the surface of the material did not evaporate (as one would expect). There some interesting speculation as to why that is. It wasn't clear whether or not the water would move across the nano-structure if it was affected by gravity (aka dripping) but I can imagine several ways to transport it off the surface so I'm sure the researchers can too.
[1] The description in the paper is that capillary action forces the vapor into the interior of the structure where it collapses into liquid.
This is basic thermodynamics, you can do however much hydrophobic/hydrophilic nanomaterials, but you won't get condensation unless you somehow conduct away the latent heat. This can be done by storing energy in the material itself (that's how desiccants work), or by providing a temperature gradient (a cooler).
Okay I think we're saying the same thing, but let me check that..
> This can be done by storing energy in the material itself (that's how desiccants work)
This is exactly where the energy goes. From the paper (in it's Materials and Methods section) -- All measurements were performed at 20° ± 0.2°C maintained by an air circulation system unless otherwise noted. The temperature of the films was controlled using a heating/cooling unit (THMS350V, Linkam Scientific Instruments, Salfords, UK) when necessary.
So the hypothesis is that the heat in the water vapor goes into the nano-pore material, which in their experiment they were actively maintaining at 20 degrees C. So yes, they are actively removing the heat created by the phase change.
One difference with desiccants is that once they are saturated you have to restore them through heating them up, but this stuff doesn't have that property.
And while it may sound like nonsense it was reproduced in another lab[1].
Apparently capillary condensation is a thing, its the popping out of the liquid water that was unexpected.
[1] With a material that could potentially defy the laws of physics on their hands, Lee and Patel sent their design off to a collaborator to see if their results were replicable.
>>>> consider a 'cube' of fins of this stuff sitting in shade with a collection bucket underneath it.
There is no cube. The droplet's are attached strongly to the surface.
If the droplets drop to a cube, you can replace the cube with a cotton mat and let the water evaporate and get a low temperature mat. And then use the difference of temperature to generate electricity https://en.wikipedia.org/wiki/Thermoelectric_generator and turn on a lamp. And now you are breaking the second law of thermodynamics.
Consider a typical unplugged dehumidifier with Calcium Chloride. It generates water that drops to a cube, but it's salt water that evaporates less than fresh water, so you can't do the trick.
If you use silica gel, the water is trapped inside the material, so there is no cube.
With this new material the droplets are on the surface, but they refuse to fall down.
With an AC you get a cube full fresh water, but it obviously work only while plugged, so there is no magic.
> And while it may sound like nonsense it was reproduced in another lab [1].
They reproduced the visible droplets in the surface of the material. In neither lab they had a cube filing process. The sentence you quoted in [1] is very misleading.
Okay, I see where we diverge. The 'cube' was something I was thinking about not in the paper. I'll see if I can describe what I was thinking and you can tell me it breaks the rules :-).
You coat a piece of aluminum with nano-pore material and hang it vertically. Air flows over it and droplets appear on its surface (based on the paper). You also hang a frame of vertical wires (unenergized just small diameter wires, kind of like a screen but without the horizontal members) in front of the sheet by 1/2 the droplet's diameter. The wires don't touch the surface, they are suspended 1/2 droplet away.
Now when a droplet forms, it grows and intersects the wire (which is not hydrophobic) Surface tension puts the droplet around the wire and it slides down to the bottom of the wire frame, impacting any other droplets that had formed below it.
The resulting liquid water drops off the bottom of the wire frame into a catch pan below.
If one of these assemblies generates net water production from RH 70% air then an array of then would generate more water.
Does hydroelectric power violate the second law of thermodynamics in your opinion? I mean
1. Drops fall from the sky
2. They collect and flow down a river
3. We use that river to generate hydroelectric power to get free energy!
Water vapor, in air, has both thermal and potential energy that under the right conditions can be converted into a more useful form. We agree on that yes?
In case of hydroelectric power, there's a temperature gradient, driven by the Sun. Water evaporates in higher temperatures, radiates the heat into space, and falls out as rain.
"Water evaporates in higher temperatures, radiates the heat into space, and falls out as rain."
The paper says, "Water vapor in the nano-pores radiates its heat into the material and comes out to the surface as liquid water."
So you don't believe that the researchers experiment did what they say it did?
That's fine, typically in science you go and see if you can reproduce it.
So you don't believe that the researchers correctly described what was going on when it did what it did?
That's fine, typically in science you go and propose a way to falsify their hypothesis and test that.
My point was simply, if the researchers were presumptively accurate in their understanding (that's the principle of giving them the benefit of the doubt), then it would imply their material would pull liquid water out of the air below the temperature and conditions in which it would normally precipitate out.
They go to some length in their exposition to describe how they think it does that and where the energy comes from and where it goes. But if you don't believe them, then sure.
> "Water vapor in the nano-pores radiates its heat into the material and comes out to the surface as liquid water."
Then the _material_ is a store of energy. Once it's exhausted, the condensation will stop.
> So you don't believe that the researchers correctly described what was going on when it did what it did?
The article is very low-quality. They must understand that their work implies the conservation law violations, so there must be some unaccounted source of energy. But they have not attempted to find it.
And it can be as simple as energy from the moving air. Or maybe an electrostatic charge, or something similar.
Once the energy source is identified, they should have calculated the efficiency of their setup, compared to regular dehumidifiers.
> Then the _material_ is a store of energy. Once it's exhausted, the condensation will stop.
The paper points out that the sample was surface that maintains a particular temperature (20 degrees C in this case). The water condenses, the material heats up, the thing its sitting on removes that excess heat to maintain the temperature. No violation of CoE or TD.
Without that temperature controller, the material would presumably continue to store the heat, which would make it hotter than the ambient temperature. By how much is, as you point out, something to be characterized.
Thermodynamics says that the heat will equalize, so that excess heat will conduct to the air around it (it's not in a vacuum so it doesn't have to radiate it). That will lower the temperature of the material which will then condense more water and heat up again. My original thought was you could enhance that conduction by putting a heatsink on one side of the material.
The paper states that inside the pores they have managed to create a space that changes the parameters around the vapor carrying capacity of the air which results in the water condensing even though it would not have condensed outside those pores. Then they go on to describe how the effects of hydrophillic and hydrophobic materials, used in conjunction, create spaces near the molecular limit of water molecules and how the forces acting on that water might result in it condensing. When the vapor does condense, the heat goes somewhere, and they assume its going into the material (reasonable assumption in my opinion) and that their temperature controlled platform is then removing it. I found the description of how that water expresses to the surface a bit more "hand wavy" but that they observed liquid water on the surface, and that it is somehow coming from the material they created, seems reasonably well supported.
I think for the purposes of this discussion we're done. I really do appreciate that you are skeptical and feel that some of the more well tested laws of physics are being violated :-). Since we can only go on what they wrote up, I did make the presumption that they too know the laws of physics and have a good faith belief that they are not being violated either. It is one of the things I look for in papers that talk about things like this. Also the journal where they published their paper, Science Advances, is a refereed journal so I would presume that the reviewers were also satisfied they weren't violating any well known laws of physics. Doesn't mean that you should believe what they say, just that it's not obviously wrong.
> When water droplets reach a certain size, the system reaches a steady state. As the volume of voids decreases with increasing ϕPE, the growth and coalescence of water droplets are slowed down.
That does not break the current laws of physics.
Form the press release:
> these films could be integrated into passive water harvesting devices for arid regions
I asume "harvesting" mean we can collect the water and drink it or use to irrigation or something interesting. Not just absorbing it like silica, even if the unusable water is visible.
Passive as using the day-night temperature different to collect water: It has been done.
Passive as a continue stream of running water: It breaks the second law of thermodynamics.
I agree, but let's try to explain the microdetails of the scenario.
The new material is very hydrophilic, so the water prefer to be attached to it than been vapor.
If the wire is even more hydrophilic then the droplets will jump and collect around the wires, but they will be so attached that they will not fall down from the lower extreme of the wires.
If the wires are not so hydrophilic, the water will prefer to keep attached to the surface, or even the droplets will be smaller to avoid the wires and the collection will stop earlier.
Tweaking smartly the hydrophilic values and separations between the wires and the separation with the surface you may get interesting capillarity effect, but the water will be trapped again.
Anyway, it's difficult to look at all the details, but at the end of the day "The second law of thermodynamics. It's now trivially easy to create a free energy:"
To add to this, there is a well-known "free energy" device design: have wicks moving water from a lower reservoir to a higher reservoir. Then use it to drive a water wheel.
It sounds good on paper because everybody knows that water can travel up a wick. But of course, if the end of the wick in the upper reservoir is submerged in the water, then water will just as happily travel _down_ the wick. And if the end of the wick is in free air, then water will not drip from it because the same capillary forces prevent it.
Looking at the paper, it seems like they put some silicon-dioxide nanoparticles on a substrate, then add a plastic (poly-ethylene) layer on top and melt it (annealing). The spaces between the nanoparticles gets partially filled with plastic. The ratio of plastic to particles is the poly-ethylene volume fraction (ϕPE). They tested different fractions and found that a certain range caused the wetting behavior.
Their experiments suggest that tiny water droplets appear inside the material at 70% RH (relative humidity). If this is true, then I expect there is a way to extract the droplets using very little energy. Ideas:
- make open collection points on the film
- use ultrasound to bounce the droplets around and consolidate them
- make the film on a material that can be saturated with water so the new droplets can easily join the flow
> So the latent heat is conducted away by the cooling apparatus, it's just not explicitly stated, to sound more sensational.
In theory, if that makes it hotter than ambient air in the process, that would be a good thing - usually we have to cool things down below ambient air to get moisture out.
Not a good thing if you want to measure maximum moisture extraction, but cooling something to ambient temperatures is a much easier task.
Would this not invalidate the conclusions of the paper? considering they are not just claiming to form water droplets, but that they do so isothermally.
It could still be a useful material, but the science would be bad.
Focusing solely on taxes misses the point that most people do not fully utilize "included" baggage allowances on domestic trips, and that is pure profit.
Let's assume a $40 bag fee: $25 cost to handle the bag, $3 tax, $12 profit.
If people pay for the bags separately, in addition to their $220 ticket, they will only pay for utilized bags, so for 1 bag, the profit will be $12.
If the $300 ticket bundle includes 2 allowed bags, but people only check 1 bag, then the profit is: $80 - 2$6 (tax) - 1$25 (cost) = $49 profit, more than 4 times bigger!
The real reason is the comparison sites as the HN commenters pointed out, but the result is not always bad, because the savings is real in many cases as people indeed would only pay for one bag on average ($220+$40 = $260) instead of $300.
I think airlines are much less happy with the separated fees than consumers, but once one airline does it, the others are forced to do it. The same happened with the international trips, which clearly has no tax reason. Many years ago it included 2 pieces of 70-pound bags, then 2 50-pound bags, then 1 50-pound bag, and now in many cases, on basic tickets, nothing at all.
Practically the whole world educates doctors with a 6-year program straight out of high school, out of which 6 years are relevant to medical education, instead of the 8 years in the US, out of which 4 are barely relevant to medical education.
The real question is why the insurance companies are pushing the annual exams very hard, not just in consumer ads, but using lots of incentives for primary care physicians.
One would assume they would not want to pay for unnecessary tests for healthy people.
So either their own research shows they save money with annual checkups in spite of what the article says, or more sinisterly, they do want to spend money to be able to justify higher premiums, because in several states they are required to spend around 80% of the premiums, and this is one easily plannable way.
Does anyone know? Perhaps someone working for an insurance company?
I work at at a large health insurance company, though not involved in decision-making around annual exams or rate-setting so take that as you will.
A lot the decision-making we do is around trying to improve the health outcomes for large populations of members at scale. When dealing with millions of members, interventions that require lots of effort and time are hard to scale up. If the data shows members with annual checkups have better health outcomes on average than members without annual checkups, that is something that's relatively cheap and easy to do with potentially significant impact.
There are other benefits to annual checkups as well - catching an expensive condition early can be the difference between a $100,000 episode of care vs. a $10,000 episode of care.
To be honest internally I've noticed the tide is shifting on annual checkups. Physician time is limited and every slot is valuable. I believe we're currently exploring virtual care options as a better alternative.
> If the data shows members with annual checkups have better health outcomes on average than members without annual checkups, that is something that's relatively cheap and easy to do with potentially significant impact.
That or it's yet another example of selection bias. There have been so so many things like this where the epidemiological data shows a correlation with health, but there isn't actually a causal link. For example, annual checkups might correlate with better health because it's a more common behavior among people who can afford to do it, and wealthier people tend to be healthier.
Here's a local study that try to provide some data - although I'm a little uncertain about the control with respect to yearly checkup (would you do yearly checkup on the control, then do nothing if you found cancer?).
Maybe I’m saying the most obvious thing ever, but with that last paragraph, you really make it sound like the American healthcare regimen is decided upon by the for-profit insurance companies.
Thanks for the link! That’s quite refreshing to hear. I didn’t realize the Affordable Care Act did so much more than ensuring availability of coverage and whatnot.
The ACA got a lot of headlines for a lot of BS but some of the really great things it did were very basic, under the radar items.
For example, a lot of the research that we are reading (including possibly the article we’re responding to) is the result of funding created by the ACA.
My favorite aspect of it is the massive push to digitization which means handwritten prescriptions have pretty much been eliminated removing an entire class of death and disease causing errors (from pharmacists misreading doctors’s handwriting).
While there are some regulations, it's basically a tug of war between business interests (insurance, hospitals, pharma, device manufacturers, testing companies, revolving door government agencies) that buy politicians and scam the government* and patients. No one would plan a health system this way, but planned economies (for the interests of regular people, not private equity) are "socialism" so we get to be the victims of life-or-death extortion rackets.
Anyway, our government continues to denounce as "authoritarian and oppressive" the tiny socialist island nation of Cuba that built an incredibly impressive health system that exports doctors (such as to Italy at the start of the ongoing pandemic) when they can't even get metal for syringes b/c of U.S. sanctions.
Not OP, but I think the underlying meaning is that the focus on profit is primary. As in when it aligns with better patient outcomes it’s going to happen and that’s great.
But probably there are a ton of scenarios where profit is anti-aligned with patient outcomes and the decisions are made still to maximize profit.
I can believe that. Not because people are wicked, but collective behaviors behind the system favoring profits more than patient outcomes. The system is extremely complex and even small biases somewhere deep can possibly have a big swing in the outcomes.
> Not OP, but I think the underlying meaning is that the focus on profit is primary. As in when it aligns with better patient outcomes it’s going to happen and that’s great.
> But probably there are a ton of scenarios where profit is anti-aligned with patient outcomes and the decisions are made still to maximize profit.
It may align in their financial interests for most of these required preventive services[0] but there are some that very obviously don't like lung cancer (it would be cheaper to let smokers die quickly than to put them on immunotherapy + SBRT) and others with weak evidence, I doubt a good cost-benefit analysis has been performed for weight counseling.
Point being is that insurers are not the final say in a lot of this, the ACA did add a lot of requirements for them. But I concede there are times they don't, OP is just being overly harsh here and "improving health outcomes" isn't an insurance-specific PR line it has been used in academia and the government for a while now, even in public health systems.
But that’s how the system is supposed to work! The goal of the insurance company is to reduce costs. The govt and the healthcare system are the parts of the system that advocate for the patient.
The groups driving "improving health outcomes" are not (just or even mostly) insurance companies but rather physician societies and government agencies like the USPSTF. We can also look to other national agencies from countries with publicly funded systems (Canada, UK, France, Australia) which share the same mission statement of "improving health outcomes" and have very similar screening recommendations as the US does.
The statement is a bit of PR speak, but it's not made to sell more products. People working in healthcare generally do care about improving health outcomes.
> People working in healthcare generally do care about improving health outcomes.
If you knew the first thing about capitalism, you would know that what one "cares about" has only the most contingent relation to the end product of their labor. In other words, what the workers care about is effectively meaningless because the workers are not in charge; the profit is.
What profit in public systems and with non-profit insurers is driving increased screening?
Nihilism aside you seem to have a deep misunderstanding of evidence based medicine. While cost is a consideration in population-level screening programmes you seem to be ignoring that it is balanced with benefit and is not decided by insurers but rather the USPSTF.
> what the workers care about is effectively meaningless because the workers are not in charge
The agency in charge of screening (USPSTF) takes the work-product of physicians and other health professionals (workers) researching and building evidence on health outcomes (what they care about) which establishes the standard of care that is then forced down by the government onto insurers.
On an individual level I can also advocate as a physician by recommend screening regimens to patients who's care I am involved in and force the insurer to pay, which is what we did for breast screening before the USPSTF caught up.
Sure if you want to take a reductionist view I am using profit (specifically the fear of liability) as a tool to force the insurer but that does not mean what I care about (reducing breast cancer deaths) is effectively meaningless.
There's no need for this tone (and similarly in your previous comment). From HN guidelines:
> When disagreeing, please reply to the argument instead of calling names. "That is idiotic; 1 + 1 is 2, not 3" can be shortened to "1 + 1 is 2, not 3."
> If the data shows members with annual checkups have better health outcomes on average than members without annual checkups, that is something that's relatively cheap and easy to do with potentially significant impact.
In the case of annual checkups, I believe insurance companies are required to cover them 100% by the Affordable Care Act:
Employer subsidized plans are also mostly compliant with ACA. Based on the trends in figure 13.3, I might even say less than 10% of Americans with employer subsidized health insurance are in non ACA compliant plans.
If you bring up a complaint, it's no longer a preventative check-up, it's addressing a complaint, which has a different billing code and different reimbursement.
I feel it's a kickback to the companies that provide care.
If I bring up any health issues I'd like to discuss at my annual exam, it's billed as a doctor visit because it's no longer "preventative" care. For the visit to be free, I have to stay silent. It also gives providers an opportunity to recommend and order expensive tests or procedures that the patient might otherwise not have pursued.
> If I bring up any health issues I'd like to discuss at my annual exam, it's billed as a doctor visit because it's no longer "preventative" care. For the visit to be free, I have to stay silent. It also gives providers an opportunity to recommend and order expensive tests or procedures that the patient might otherwise not have pursued.
They tried to bill me for that in the past at practices I was a patient of. There's a fine line between preventative care and E/M. You can generally walk the "preventative care" line by presenting your concerns as an observed change to be documented rather than a problem to be solved.
If they do charge you, call the office to appeal the billing and they generally drop it as long as you can push the point that you weren't seeking a specific treatment but rather were just informing the doctor of a change in your health or conditions since the last visit.
Oh yea just call and talk to someone its easy and its not like you are going to be put through the ringer talking to 10 different people over several weeks inexplicably over several continents.
I've not found that to be an issue with smaller practices. Most of the times small practices just have one person other than the doctor who deals with billing. Sure they often outsource past that but if you can get either the doc or that person, they'll often just change the codes because even if they can technically bill you, it's probably not worth the time or effort for them.
But yeah at big practices good luck. They are a living nightmare to deal with and I feel for anyone who can't get access to a smaller (ideally solo) practice.
Wild speculation is a combination of one insurance company offering it and it becoming a relatively low cost competitive bullet point on one hand.
On the other hand, insurers probably have better actuarial data because of annual checkups and can better align their profit margins with fees. Thus reducing their own reinsurance fees.
Imagine you are an insurer and advise free annual checkups. Some of your patients don't bother. Those patients have a higher mortality. You conclude the annual checkup is good.
But you might be deceiving yourself - the kind of people to ignore health advice about getting an annual checkup might also be the kind of people to ignore the health advice on the back of a cigarette packet...
Sure, they understand the problem... But is there anything they can do about it?
I'm not aware of insurance companies being too keen on getting into medical experiments like 'people with a birthday on a Thursday don't get the free annual checkup'.
There was a case here in New Zealand where the "not for profit" insurance company "Southern Cross" was owned by a group of doctors.
You can see how something that might not be in the insurance company's best interest could be in owners best interest, particularly if they own the hospital too.
My work offers free annual check ups and it’s mostly DIY. Prick of a finger, punch in weight, height and blood pressure into web app. Eventually once the results on the blood return, you get feedback on cholesterol etc. I get $500 from it and it is psychological to an extent - it helps encourage healthier habits
That's simply not how the medical insurance business works. Since the Affordable Care Act, insurers have almost no ability to pick and choose their customers. And since profit margins are capped there is like little incentive to "save" money by reducing medical expenses.
That's not true because they can pick and choose where and what to offer based on geographic areas through the ACA plans. But even more selectively they can offer group plans to employers that incentivize maintaining a healthy workforce. Most unhealthy people don't work good jobs that provide insurance.
Under the ACA, insurance companies have a profit cap as a percentage of expenditures, so they need to drive expenses to increase total profit (but still have to be competitive price-wise so it isn't unlimited).
Around here the insurance companies created a billing code that is just for annual checkups, with discussion of ongoing care turning it into a different type of visit (that isn't necessarily free).
SMS forwarding sends the content, not the sender (phone number) info. In principle, they can search your previous messages and find the sender, but it's unclear if that would raise some privacy issues.
Most likely they just use the reported message to train their spam filter, not to block the particular sender number of that message.
You're probably right, but mining the results of that trained filter should provide quite a bit of data to a telco even so. It's not like it's a new bad actor for every message.
On the other hand, people in more industrial countries are exposed to different chemicals (BPA, FPOAs, flame retardants, food additives, etc.), than people in more agrarian countries (field chemicals, like fertilizers and pesticides). These chemicals are all harmful, but it's hard to blame a single class of them for a global problem.
If I had to pick a truly universal issue, I would say childhood and young adult obesity. Surprisingly, obesity is growing rapidly even in countries where hunger is also a problem.
Perl is preinstalled on pretty much every Linux and MacOS since time immemorial, and it's pretty much guaranteed to stay preinstalled for the foreseeable future.
Python3 is up and coming, and eventually it will get there, but old machines must die before it can reach ubiquity.
It will be a long time before it makes sense to use python where longevity/portability matter.
Python breaks backwards compatibility with old scripts every six months or so. In practice, this means you have to port scripts every time you switch machines. Virtual environments sometimes address this issue, but they are hit or miss.
In contrast, perl scripts from 1999 often work unchanged on clean 2022 OS installs.
Yes, I would consider awk and sh lingua francae (?) alongside Perl – but in slightly different contexts, namely low-complexity jobs.
I find Perl slightly more suitable once things get a little complicated, mainly because it's footgun:power ratio is better than awk (few footguns, but also very low power) and sh (many footguns, not that powerful).
I have come across plenty of boxen where bc was not installed, so I don't put that in that bucket.
And yes, if I want to describe text changes in a highly portable way, I will use sed (or ed, depending on context) rather than, say, unified diffs. I could accept an argument that unified diffs are also a lingua franca for more complicated changes, but they are harder to write.
Then what would, in your opinion, make it "lingua franca"?
I took it to mean "so common that it's available almost anywhere" (which is consistent with the context of the comment).
I've found it extremely useful to rely in tools such as the ones you just listed. Specially because they are often present even in light vms were perl might not.
People like the convenience of having their bookmarks and saved passwords available, so the Incognito mode serves a purpose, it's just not what its name implies. Only its name is a problem, the description on the starter page correctly describes the behavior.
"Guest Mode": (1) hides the identity on the internet, and (2) hides the activity on the local machine.
"Incognito window": (2 only) hides the activity on the local machine.
To clear the confusion, "Incognito mode" should simply be renamed "Ephemeral mode" or "Transient mode" or "No-Save mode".
"All measurements were performed at 20° ± 0.2°C maintained by an air circulation system unless otherwise noted. The temperature of the films was controlled using a heating/cooling unit (THMS350V, Linkam Scientific Instruments, Salfords, UK) when necessary."
So the latent heat is conducted away by the cooling apparatus, it's just not explicitly stated, to sound more sensational.