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There were similar comments on HN. The argument goes that since it takes energy to produce PV panels and wind turbines, China effectively is an energy exporting country. What’s even better is some of the PV and turbines are produced with renewable energy. And unlike oil and gas, which are used only once, PV panels and wind turbines generate power for many years.

That traditional biomass stove in paper's figures is perhaps the worst stove imaginable. Its efficiency could below 10%. Better designed stove has efficiency above 30% and has much less indoor air pollution.

That being said, the more I read it, the more I like this PV steam cooker. It is simple and easy to scale up by adding more PV panels and more sands. Although Ghana is close to the equator, I wonder whether it worth to steer the PV panels during the day.

Edit, efficiency measured by energy transferred to boiling water or cooking vs energy released from burning biomass.

I used LLM to rewrite above comment to make it sounds less negative. Then I read those two chapters again. This book adds complexities to simple concepts. There are good math books for non-math majors, but this isn't one of them.

Another JPEG XR user is Zeiss. It saves both grayscale and color microscope images with JPEG XR compression in a container format. Zeiss also released a C++ library (libczi) using the reference JPEG XR implementation to read/write these images. Somehow Zeiss is moving away from JPEG XR - its newer version of microscope control software saves with zstd compression by default.

Agreed.

I really appreciate author’s effort and for releasing the PDF to the public. There are however areas I think could be made more helpful.

In the chapter on Trigonometric Functions, it begins with discussion of the derivative of the exponential function is itself, and then moves on to define sine and cosine via second degree derivatives. While interesting, this may not be the most helpful approach for intended readers.

The following chapter on Taylor Series also starts with a long discussion about the value of e. It is interesting, but it can feel a bit distracted from the main topic. The treatment of Taylor polynomials might benefit from a different approach similar to other texts.

Looks like farm land. Perhaps the land was assigned to individual in small pieces, and the individual get a portion of the harvest.

"Fourier was obsessed with heat, keeping his rooms uncomfortably hot for visitors, while also wearing a heavy coat himself." [1]

[1]. The Fourier Transform and Its Applications. (Ronald Bracewell)

GP likely means defibrillator. EKG along won't save life and it requires training to read EKG. An AED has a built-in smart EKG that can identify shockable fibrillation. There is also automatic CPR machine that can do chest compression. However manual CPR is still light years better than no CPR.

High voltage DC power line can transfer electricity over long distances with little loss. So it is preferable to build a nuclear power station far away from densely populated area. The proposed plan near my home was close to a lake, as compared to near a running river or sea. That raised more concerns. Thankfully it stayed as plan and had been forgotten. I googled and could not find it.

My home is safe now. But I still think nuclear power in its current state is not a responsible option. The spent fuel remains dangerous after hundreds or thousands years.

I was a huge fan of nuclear power, until I heard a plan to build one 50 km from my home.

To understand the significance of artificial skin, first consider all sorts of bad things that happen after deep burn. The dead tissue in a burn wound can release toxins and provide nutrients for bacteria to grow, which in turn can spread toxins and infection throughout the body, eventually causing multiple organ failure and death. Early treatment of deep burns focuses on interrupting this cascade reaction by removing the dead tissue. The now-cleaned wound needs to be covered. Skin from many species, including chicken, rat, pigeon, cat, dog, frog, cow, and pig, has been tested, and pig skin was found to be the best. As the wound's condition improves, healthy skin from the same patient is grafted or seeded onto the wound to assist healing. Although pig skin is still widely used, the biggest problem is that it is from a different species and therefore can be immune rejected. Gene-edited pig skin helps, but it may still require immunosuppressive therapy, which is not helpful when the patient is at high risk of infection.

Artificial skin has the potential for better temporary wound cover, and ideally, it can promote healing without skin grafting or using less skin for grafting.

First impression from this list is that Russia has a lot of mathematicians!

From the list, I have only read What is Mathematics? by Courant, which is a well-known and excellent book. I’d add Princeton Companion to Mathematics as a more advanced version, and Mathematical Methods in the Physical Sciences by Mary Boas as a more detailed alternative to What is Mathematics, to the list. Other titles on the list, such as those on probability or linear algebra, are perhaps less well-known.

There were four:

  NS savannah (US): 1962 to 1971, too expensive to operate
  NS Mutsu (Japan): 1972 to 1992, neutron leak
  Otto Hahn (Germany): 1970 to 1982, converted to diesel power
  Sevmorput (Russian): 1988 to 2007, converted to world's first nuclear powered drilling ship

As much as we want the next generation ships with less CO2 emissions, that nuclear cargo ship is not coming anytime soon. It will use a Thorium melting salt reactor, which although not new, is still in experiment. US first proposed melting salt reactor in the 1940s and had operated one briefly in the 1960s. China is building and testing an experimental Thorium reactor. It made the news earlier this month for been successfully converting Thorium to Uranium, perhaps means it is actually burning Thorium as compare to rely on Uranium in previous melting salt reactors. The news also states the plan has 3 stages: experimental reactor, research reactor, and demonstration reactor. The current one is at first stage. The third stage, demonstrator reactor, is scheduled to build in 2035. Therefor that nuclear cargo ship is at least another 10 years from now.

Indeed, it's a very impressive speed. I have been on few ships of similar size as this sailboat. With their huge, extremely loud, hot, and diesel hunger engine they usually cruise at less than 15 knots. Container ships are outliers. Not sure how much more fuel they burn when sailing at 25 knots vs 15 knots. But they use cheaper heavy oil so perhaps are less sensitive to fuel cost.

Also the same speed feels faster at sea than on the land because waves make sailing like drive off-road. A small boat can feel like fly at 30 knots. 11 knots makes a joyful ride.

Very interesting modification. Perhaps it can be an optional accessory.

The Ludlum mode 3 is an amazingly steady instrument and looks like it can last forever. I only hope its user interface can be improved a little bit. It is not obvious how to turn it off because there are two Off labels. One is for sound and the other is for power. Panel around the sound switch looks like:

    ON
  switch
    OFF
    AUD
  button
   RESET

Because AUD can be read as belongs to the reset button below, people turn off the sound and think they have switched off the meter :). The ON/OFF sound switch can be labeled as Unmute/Mute.

Canada has an unique advantage in dealing with China that many don't realize or underestimate. Unlike many other countries, Canada holds a very special place for many Chinese people. Dr. Norman Bethune, who died during World War II while working in a field hospital, is a highly respected physician and a household name in China; There was a very catchy song from a Canadian potash TV commercial that many Chinese people remember from the early days when many Chinese watch the TV for the first time; Mark Henry Rowswell (aka Dashan) is perhaps the best-known stand-up comedian in China. Overall, I’d say Canada occupies a warm and special place in the hearts of Chinese people, including the age group of current administration. I don’t understand how the two countries have become hostile toward each other.

Learning Emacs is easy, I have done it many times...

Nowadays I open Emacs exclusively for magit. I only know perhaps less than 5 magit commands, however, even use it for staging changes is such a huge leap and its chunk staging is indispensiable.

Learning Chinese is not easy. That being said, one does not need to know Chinese in order to work with peers or business partners from China. For working in China, while knowing the local language is certainly an advantage, it is not a requirement, especially in science and technology. I have met a few scientists and exchange scholars in China. They basically only know how to say "Good morning," "Thank you," or "Sorry, I don't know how to say it in Chinese." One can expect co-workers to speak English. Buses and subways in big cities announce stops in English. There is English on road signs. Restaurant menus may not have English, but they likely have photos, or perhaps you can just surprise yourself anyway.

There is a new K visa that is granted to anyone holds a STEM degree from a well-established college anywhere in the world. People can come to China first and then look for a job. This K visa is less than a month old, so it is unclear how it works. Getting a job is a different story. Past data shows that non-state-owned small businesses created more than 90% of new jobs. Perhaps because they have not fully recovered, the job market is tight.

This is amazing! That HIFU 20 years ago used phase array to steer beam. Don't know the size of transducer. One of the tests I heard of was on a pig leg. The damage was bigger than expected, could be in the range of few centimeters, probably due to the leg has skin, subcutaneous fat, muscle and bone. All have different sound characteristic.

It's likely for Dutch. China exported 2414 metric tons of CeO2 in that period. The top 4 destinations are Netherlands (517 tons), Italy (438 tons), Japan (353 tons), USA (284 tons). So others can import it themselves just fine.

There was a startup in Shanghai in the early 2000. Their device used multiple transducers. The probe was at least 40 cm in diameter. They did trials on uterine fibroids, among other diseases. One of the difficulties was while it looks good in theory, but the path ultrasound travels in the body is more complicated than, say x-ray or gamma ray. They expected a fine focal zone, but sometimes the focal zone was much larger than expected. This new wave of ultrasound equipment may have discovered better ways to control the sound beam.

Netherlands imported more CeO2 (a rare earth) from China than any other country, with 517 metric tons during the first half of 2025.

> Edit: I just rechecked China and wow! $0.08 per kWh. Can anyone confirm?

Yes, it is in the ballpark of $0.08/kWh. It varies a little bit across regions. Also in some places the price is only half during the night. But as you consume more power, you may see the price rise to $0.12/kWh.

In 2024, cost of renewable + storage was 0.52-0.88 CNY/kWh($0.08-$0.12). Advancement in storage is expected to drive that cost down by more than 50%.

Are the cleaning crews federal employees? Who is taking out the trash and maintaining the restrooms during the shutdown?

Exactly! Few people may care about climate or whether energy is clean, but I'd argue that for most people, the cost is more important. My friend in Shanghai owns a BYD EV. The electricity cost is equivalent to around 2 Liters of gasoline per 100 km. That’s more than 100 MPG. If he charges during the night hours when electricity costs only half, he gets 200 MPG!

I used a different model of Palm and miss it. It is simple and just works. Ironically, with the current much more powerful smartphone, I have yet to find something similar to the Palm. The only downside of Palm was its frustrating touchscreen.

I mostly use text(markdown) these days.

Almost all the cooking I do are using microwave. While they are not bad, there are certain critical steps microwave cannot do. For example enrich the flavor of garlic and other spices in hot cooking oil. I found microwave is not good at heating vegetable oil and the garlic is more like boiling in lukewarm oil instead of frying. Also it heats food inside out equally as compared to stove which transmit heat from the out layer to inside, as result the food have different textures.

My workplace has two Windows 10 machines, one in daily use, and the other is mostly idle. Both are extremely slow. The one in daily use takes at least 15 minutes to become usable after boot. The other is not much better. They are domain-controlled so not much we can do to improve. In contrast, we still have a 20+ years computer, which has an IDE hard drive, running Windows 2000 with MS Office to operate an instrument, and it is much more responsive.

Thanks for the link! I didn't know they were using soda-lime glass and still call it Pyrex. In the meantime, the Pyrex labware remains real: I routinely pour liquid nitrogen into room-temperature Pyrex beakers without issue. That is a sudden temperature change of 220°C or 400°F.