The Genius Of Slide Rule Precision

Most people have heard of or seen slide rules, with older generations likely having used these devices in school and at their jobs. As purely analog computers these ingenious devices use precomputed scales on slides, which when positioned to a specific input can give the output to a wide range of calculations, ranging from simple divisions and multiplications to operations that we generally use a scientific calculator for these days. Even so, these simple devices are both very versatile and can be extremely precise, as [Bob, the Science Guy] demonstrates in a recent video.

Slide rules at their core are very simple: you got different scales (marked by a label) which can slide relative to each other. Simple slide rules will only have the A through D scales, with an input provided by moving one scale relative to the relevant other scale (e.g. C and D for multiplication/division) after which the result can be read out. Of course, it seems reasonable that the larger your slide rule is, the more precision you can get out of it. Except that if you have e.g. the W1 and W2 scales on a shorter (e.g. 10″) slide rule, you can use those to get the precision of a much larger (20″) slide rule, as [Bob] demonstrates.

Even though slide rules have a steeper learning curve than punching numbers into a scientific calculator, it is hard to argue the benefits of understanding such relationships between the different scales, and why they exist in the first place.

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Whole-Fruit Chocolate: Skipping The Sugar By Using The Entire Cacao Pod

Images of whole-fruit chocolate formulations after kneading at 31 °C and subsequent heating to 50 °C. The ECP concentration in the sweetening gel and the added gel concentrations into the CM are shown on the x and y axis, respectively. (Credit: Kim Mishra et al., Nature Food, 2024)
Images of whole-fruit chocolate formulations after kneading at 31 °C and subsequent heating to 50 °C. The ECP concentration in the sweetening gel and the added gel concentrations in the CM are shown on the X and Y axes, respectively. (Credit: Kim Mishra et al., Nature Food, 2024)

It’s hard to imagine a world without chocolate, and yet it is undeniable that there are problems associated both with its manufacturing and its consumption. Much of this is due to the addition of sugar, as well as the discarding of a significant part of the cacao pod, which harbors the pulp and seeds. According to a study by [Kim Mishra] and colleagues in Nature Food, it might be possible to ditch the sugar and instead use a mixture of cacao pulp juice (CPJC) and endocarp powder (ECP), which are turned into a sweetening gel.

This gel replaces the combination of sugar with an emulsifier (lecithin or something similar) in current chocolate while effectively using all of the cacao pod except for the husk. A lab ran a small-scale production, with two different types of whole-fruit chocolate produced, each with a different level of sweetness, and given to volunteers for sampling. Samples had various ECP ratios in the gel and gel ratios in the chocolate mixture with the cacao mass (CM).

With too much of either, the chocolate becomes crumbly, while with too little, no solid chocolate forms. Eventually, they identified a happy set of ratios, leading to the taste test, which got an overall good score in terms of chocolate taste and sweetness. In addition to being able to skip the refined sugar addition, this manufacturing method also cuts out a whole supply chain while adding significantly more fiber to chocolate. One gotcha here is that this study focused on dark chocolate, but then some chocolate fans would argue vehemently that anything below 50% cacao doesn’t qualify as chocolate anymore, while others scoff at anything below 75%.

Matters of taste aside, this study shows a promising way to make our regular chocolate treat that much healthier and potentially greener. Of course, we want to know how it will print. Barring that, maybe how it engraves.

Recycling Of Portland Cement And Steel In Electric Arc Furnaces

The use of concrete and steel have both become the bedrock of modern-day construction, which of course also means that there is a lot of both which ends up as waste once said construction gets demolished again. While steel is readily recyclable, the Portland cement that forms the basis of concrete so far is not. Although the aggregate from crushed concrete can be reclaimed, the remainder tends to end up in a landfill, requiring fresh input of limestone to create more cement. Now a team of researchers from the University of Cambridge claim to have found a way to recycle hydrated Portland cement by using it as flux during steel production in electric arc furnaces (EAFs).

Not only does this save a lot of space in landfills, it also stands to reduce a lot of the carbon dioxide produced during cement and steel production, which is primarily from the use of limestone for cement and lime-dolomite for steel. The details can be found in the open access paper in Nature by [Cyrille F. Dunant] and colleagues. Essentially reclaimed cement paste is mixed with some fresh material to form the flux that shields the molten steel in an EAF from the atmosphere. The flux creates the slag layer that floats on top of the molten steel, with this slag after cooling down being ground up and turned into cement clinker, which is then mixed to create fresh cement.

The process has been patented by Cambridge, who call the product ‘Cambridge Electric Cement‘, with the claim that if using low-carbon power sources for the EAF like hydro and nuclear, it would constitute ‘no emissions’ and ‘no landfill’ cement. We have to see how this works out on an industrial scale, of course, but it would definitely be nice to keep concrete and cement in general out of landfills, while cutting back on limestone mining, as well as questionable practices like adding heavy metal-laden fly ash as filler to concrete.

Thanks to [cscott] for the tip.

The Long Road Towards Reverse Engineering The ESP32 Wi-Fi Driver

Although much of the software that runs on the ESP32 microcontroller is open source, the Wi-Fi driver is not. Instead, it uses a proprietary binary blob. This was no problem for [Jasper Devreker]’s reverse-engineering of the ESP32’s Wi-Fi stack so far until he came face to face with reverse-engineering the initialization of the Wi-Fi peripheral. As it turns out, there is a lot of work involved after you call esp_phy_enable in the Espressif binary blob, with the team logging 53,286 peripheral accesses during the initialization phase. In comparison, sending a Wi-Fi packet takes about ten calls.

Currently, the way that the initialization step is handled is by having the initialization routine in the binary blob do its thing by configuring the radio and other elements before killing the FreeRTOS task and replacing it with their own version. The team is actively looking for a clean approach for moving forward that will avoid simply writing everything from scratch. For the Wi-Fi MAC, existing code (e.g., FreeBSD’s stack) could be used, but the radio code is much more of a headache. Clearly, there’s still a lot more work to be done in order to get a fully open-source Wi-Fi MAC and stack for the ESP32, but having the community (that’s you) pitch in might speed things up if there’s demand for an open-source driver.

[Jasper’s] been working on this for a while. He’s even built a Faraday cage to make the task easier.

Hunting For Part Numbers: Analyzing The Buck Converter On Mini 560 Modules

Some of us may have recently stumbled over these mysterious ‘Mini 560’ synchronous buck converter modules at various e-shopping websites. These little modules claim to take in 7-20 VDC and output whatever voltage they’re configured for (e.g., 5 VDC). What IC is used on these modules? Since the IC on these modules has had its markings laser-etched away, answering that particular question is a tedious sleuthing job. Fortunately, [MisterHW] has done the legwork for us already, with a detailed write-up.

Details like the nominal input rating, measured currents, and resulting efficiency values provide clues. Looking at the 0603 SMD resistor values for given output voltages provides the programming resistances, combined with the footprint of the QFN-20 package. After desoldering the IC on a sample board, the footprint was reminiscent of certain Texas Instruments (Ti) packages, leading to a perusal of the Ti parametric database and a couple of candidate matches.

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ICQ Will Shut Down On June 26 This Year

In many ways, ICQ has always been a bit of a curiosity. It was one of the first major instant messenger clients of the 1990s. It saw broad uptake alongside the likes of AOL Instant Messenger and MSN Messenger. Yet, it outlasted both of them despite not being attached to an industrial juggernaut like AOL or Microsoft. After 27 years, however, it seems that the last petal will drop, with the shutdown of ICQ announced on the ICQ website for June 26, 2024.

Originally launched by an Israeli company, Mirabilis, in June of 1996, it took the Internet by storm, leading to AOL buying Mirabilis in June of 1998. Under the wing of AOL, ICQ kept growing its user base until it was sold to Digital Sky Technologies (now VK, which operates in 2010. Around this time, the likes of Facebook and Google, with their own messaging solutions, came onto the scene, leaving ICQ to flounder. Ultimately, ICQ found a new home in the Russian market as a mobile messaging system until its imminent shutdown. Users are urged to move to the VK Messenger instead.

The demise of ICQ obviously led to a blast of nostalgia on sites like Hacker News, even though it has lost relevance in the West for many years. We’re sad to see this chapter end and will mourn the demise of our UINs (RIP, 61007952) along with our fellow compatriots in the usual IRC channels.

This is what happens when you depend on the grid. Going off the grid doesn’t have to look homemade, either.

Germany’s Solar Expansion And The Negative Effects Of Electricity Overproduction

Amidst the push for more low-carbon energy, we see the demolishing of one of the pillars of electric grids: that of a careful balancing between supply and demand. This is not just a short-term affair. It also affects the construction of new power plants, investments in transmission capacity, and so on. The problem with having too much capacity is that it effectively destroys the electricity market, as suppliers need to make a profit to sustain and build generators and invest in transmission capacity. This is now the problem that Germany finds itself struggling with due to an overcapacity of variable renewable power sources (VRE) like solar and wind.

With a glut of overcapacity during windy and sunny days, this leads to prices going to zero or even negative. While this may sound positive (pun intended), it means that producers are not being paid. Worse, it means that when, for example, France buys German wind power for negative Euros via the European Electricity Exchange (EEX), it means that Germany actually pays France, instead of vice versa. The highly variable output of wind and solar also means a big increase in curtailment and redispatch measures to keep the grid stable, all of which costs money and drives up operating costs.

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