Author: Maya Posch

1867 Articles

The Coming Copper Shortage: Aluminium Or Carbon Nanotubes To The Rescue?

September 30, 2021 by 90 Comments

The use of aluminium in wiring is unlikely to bring a smile to the face of anyone who has had to deal with it in a 1960s, or early 1970s-era house. The causes behind the fires and other accidents were myriad, including failure to deal with the higher thermal expansion of aluminium, the electrically insulating nature of aluminium oxide, and the general brittleness of aluminium when twisted.

Yet while copper is superior to aluminium in terms of electrical conductivity and ease of installation, copper prices have skyrocketed since the 1970s, and are on the verge of taking off to the moon. A big part of the reason is the increased use of copper in everything from electronics and electrical motors to generators, driven by large-scale deployment of wind turbines and electrical vehicles.

As the world moves to massively expand the use of electrical cars and installation of wind turbines, copper demand is predicted to outstrip current copper supply. With aluminium likely to make a big return as a result, it’s worth taking a look at modern-day aluminium-based wiring, including copper-clad aluminium and the use of carbon-based replacements. Continue reading “The Coming Copper Shortage: Aluminium Or Carbon Nanotubes To The Rescue?” →

Image of CFS's SPARC reactor

Commonwealth Fusion’s 20 Tesla Magnet: A Bright SPARC Towards Fusion’s Future

September 27, 2021 by 62 Comments

After decades of nuclear fusion power being always ten years away, suddenly we are looking at a handful of endeavours striving to be the first to Q > 1, the moment when a nuclear fusion reactor will produce more power than is required to drive the fusion process in the first place. At this point the Joint European Torus (JET) reactor holds the world record with a Q of 0.67.

At the same time, a large international group is busily constructing the massive ITER tokamak test reactor in France, although it won’t begin fusion experiments until the mid-2030s. The idea is that ITER will provide the data required to construct the first DEMO reactors that might see viable commercial fusion as early as the 2040s, optimistically.

And then there’s Commonwealth Fusion Systems (CFS), a fusion energy startup.  Where CFS differs is that they don’t seek to go big, but instead try to make a tokamak system that’s affordable, compact and robust. With their recent demonstration of a 20 Tesla (T) high-temperature superconducting (HTS) rare-earth barium copper oxide (ReBCO) magnet field coil, they made a big leap towards their demonstration reactor: SPARC.

A Story of Tokamaks

CFS didn’t appear out of nowhere. Their roots lie in the nuclear fusion research performed since the 1960s at MIT, when a scientist called Bruno Coppi was working on the Alcator A (Alto Campo Toro being Italian for High Field Torus) tokamak, which saw first plasma in 1972. After a brief period with a B-revision of Alcator, the Alcator C was constructed with a big power supply upgrade. Continue reading “Commonwealth Fusion’s 20 Tesla Magnet: A Bright SPARC Towards Fusion’s Future” →

Mechanisms Behind Vaccine Side-Effects: The Science That Causes That Sore Arm

September 21, 2021 by 85 Comments

After receiving a vaccination shot, it’s likely that we’ll feel some side-effects. These can range from merely a sore arm to swollen lymph nodes and even a fever. Which side-effects to expect depend on the exact vaccine, with each type and variant coming with its own list of common side-effects. Each person’s immune system will also react differently, which makes it hard to say exactly what one can expect after receiving the vaccination.

What we can do is look closer at the underlying mechanisms that cause these side-effects, to try and understand why they occur and how to best deal with them. Most relevant here for the initial response is the body’s innate immune system, with dendritic cells generally being among the first to come into contact with the vaccine and to present the antigen to the body’s adaptive immune system.

Key to the redness, swelling, and fever are substances produced by the body which include various cytokines as well as prostaglandin, producing the symptoms seen with inflammation and injury.

Continue reading “Mechanisms Behind Vaccine Side-Effects: The Science That Causes That Sore Arm” →

Powering Up With USB: Untangling The USB Power Delivery Standards

September 16, 2021 by 37 Comments

Powering external devices directly from a PC’s I/O ports has been a thing long before USB was even a twinkle in an engineer’s eye. Some of us may remember the all too common PS/2 pass-through leads that’d tap into the 275 mA that is available via these ports. When USB was first released, it initially provided a maximum of 500 mA which USB 3.0 increased to 900 mA.

For the longest time, this provided power was meant only to provide a way for peripherals like keyboards, mice and similar trivial devices to be powered rather than require each of these to come with its own power adapter. As the number of  computer-connected gadgets increased USB would become the primary way to not only power small devices directly, but to also charge battery-powered devices and ultimately deliver power more generally.

Which brings us to the USB Power Delivery (USB-PD) protocol. Confusingly, USB-PD encompasses a number of different standards, ranging from fixed voltage charging to Programmable Power Supply and Adjustable Voltage Supply. What are the exact differences between these modes, and how does one go about using them? Continue reading “Powering Up With USB: Untangling The USB Power Delivery Standards” →

Lithium Mine To Battery Line: Tesla Battery Day And The Future Of EVs

September 14, 2021 by 15 Comments

After last year’s Tesla Battery Day presentation and the flurry of information that came out of it, [The Limiting Factor] spent many months researching the countless topics behind Tesla’s announced plans, the resource markets for everything from lithium to copper and cobalt, and what all of this means for electrical vehicles (EVs) as well as batteries for both battery-electric vehicles (BEVs) and power storage.

A number of these changes are immediate, such as the use of battery packs as a structural element to save the weight of a supporting structure, while others such as the shift away from cobalt in battery cathodes being a more long-term prospective, along with the plans for Tesla to set up its own lithium clay mining operation in the US. Also impossible to pin down: when the famous ‘tabless’ 4680 cells that Tesla plans to use instead of the current 18650 cells will be mass-produced and when they will enable the promised 16% increase.

Even so, in the over 1 hour long video (also linked below after the break), the overall perspective seems fairly optimistic, with LFP (lithium iron phosphate) batteries also getting a shout out. One obvious indication of process to point out is that the cobalt-free battery is already used in Model 3 Teslas, most commonly in Chinese models.

Continue reading “Lithium Mine To Battery Line: Tesla Battery Day And The Future Of EVs” →

The Dark Side Of Package Repositories: Ownership Drama And Malware

September 8, 2021 by 77 Comments

At their core, package repositories sound like a dream: with a simple command one gains access to countless pieces of software, libraries and more to make using an operating system or developing software a snap. Yet the rather obvious flip side to this is that someone has to maintain all of these packages, and those who make use of the repository have to put their faith in that whatever their package manager fetches from the repository is what they intended to obtain.

How ownership of a package in such a repository is managed depends on the specific software repository, with the especially well-known JavaScript repository NPM having suffered regular PR disasters on account of it playing things loose and fast with package ownership. Quite recently an auto-transfer of ownership feature of NPM was quietly taken out back and erased after Andrew Sampson had a run-in with it painfully backfiring.

In short, who can tell when a package is truly ‘abandoned’, guarantee that a package is free from malware, and how does one begin to provide insurance against a package being pulled and half the internet collapsing along with it?

Continue reading “The Dark Side Of Package Repositories: Ownership Drama And Malware” →

Screenshot of MacOS Lunar app

Controlling External Monitors On M1 Macs With Undocumented APIs

September 8, 2021 by 8 Comments

Display Data Channel (DDC) is a very useful feature of modern digital displays, as it allows the graphics card (and thus the OS) to communicate with a display and control features such as brightness and contrast. The biggest negative aspect here is the relatively poor access to this feature within an operating system like MacOS, which can change on a whim, as [Alin Panaitiu] found out recently.

Current displays implement DDC2, which is based around an I2C bus. Despite this, few OSes offer DDC-based control of features such as brightness which is where [Alin] developed a popular utility for MacOS that used undocumented APIs to talk DDC2 with external monitors via I2C. Until the new Arm-based Mac systems got released and these undocumented APIs got changed, that is.

Even though there are some ways around this, with some utilities using a simple software-based overlay to ‘dim’ the display, or using an external gamma adjustment via an external Raspberry Pi system hooked up to HDMI and using ddcutil, the best way is still via DDC2. Ultimately the new (undocumented) APIs that provide access were discovered, with another user going by the name [zhuowei] notifying [Alin] of the new IOAVServiceReadI2C and IOAVServiceWriteI2C methods with Arm-based MacOS.

After this it took some more sleuthing to figure out which of the devices on the I2C bus were which monitor in the case of multiple external monitors, but in the end it all worked again, adding hardware-based brightness controls back in the hands of MacOS users. Minus a few apparent hardware issues with HDMI on the M1 Mac Mini and some displays, but who is counting?

[Heading image: Screenshot of the Lunar app on MacOS. Credit: Alin Panaitiu]