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A Crash Course In Thermodynamics For Electrical Engineers

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It’s a simple fact that, in this universe at least, energy is always conserved. For the typical electronic system, this means that the energy put into the system must eventually leave the system. Typically, much of this energy will leave a system as heat, and managing this properly is key to building devices that don’t melt under load. It can be a daunting subject for the uninitiated, but never fear — Adam Zeloof delivered a talk at Supercon 2019 that’s a perfect crash course for beginners in thermodynamics.

Adam’s talk begins by driving home that central rule, that energy in equals energy out. It’s good to keep in the back of one’s mind at all times when designing circuits to avoid nasty, burning surprises. But it’s only the first lesson in a series of many, which serve to give the budding engineer an intuitive understanding of the principles of heat transfer. The aim of the talk is to avoid getting deep into the heavy underlying math, and instead provide simple tools for doing quick, useful approximations.

Conduction and Convection

Conduction is the area first explored, concerning the transfer of heat between solid materials that are touching. Adam explains how this process is dependent on surface area and how this can be affected by surface condition, and the reasons why we use thermal paste when fitting heatsinks to chips. The concept is likened to that of electrical resistance, and comparisons are drawn between heat transfer equations and Ohm’s law. Thermal resistances can be calculated in much the same way, and obey the same parallel and series rules as their electrical counterparts.

With conduction covered, the talk then moves on to discussion of convection — where heat is passed from a solid material to the surrounding fluid, be it a liquid or a gas. Things get a little wilder here, with the heat transfer coefficient h playing a major role. This coefficient depends on the a variety of factors, like the fluid in question, and how much it’s moving. For example, free convection in still air may only have a coefficient of 5, whereas forced air cooling with a fan may have a coefficient of 50, drawing away 10 times as much heat. Adam discusses the other factors involved in convection, and how surface area has a major role to play. There’s a great explanation of why heatsinks use fins and extended surfaces to increase the heat transfer rate to the fluid.

Modelling Thermodynamics

[Adam] demonstrated a heat transfer simulation running on the Hackaday Superconference badge, to much applause.

With the basics out of the way, it’s then time to discuss an example. Given the talk is aimed at an electrical engineering audience, Adam chose to cover the example of a single chip in the middle of a printed circuit board. In three dimensions, the math quickly becomes complex, with many differential equations required to cover conduction and all the various surfaces for convection. Instead, the simulation is simplified down to a quasi-1-dimensional system. Some imperfect assumptions are made to simplify the calculations. While these are spurious and don’t apply in many circumstances, chosen properly, they enable the simple solution of otherwise intractable problems — the magic of engineering! After showing the basic methods involved, Adam shows how such an analysis can be used to guide selection of different cooling methods or heatsink choices, or make other design decisions.

The talk is a great primer for anyone wanting to take a proper engineering approach to solving thermal problems in their designs. And, as a final party piece, Adam closed out the talk with a demonstration of a heat transfer simulation running on the conference badge itself. Thermodynamics can be a dry topic to learn, so it’s great to see a straightforward, intuitive, and engineering-focused approach presented for a general technical audience!



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Purported OnePlus 8 specs leak contains a few surprising revelations

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The first wave of 2020 flagship Android phones is here, with the Galaxy S20 and Xiaomi Mi 10 being the first phones to rock Qualcomm’s brand new Snapdragon 865 processor, which comes with built-in 5G connectivity. These phones also feature insane specs when it comes to RAM and storage, with the 16GB/512GB Galaxy S20 Ultra being a phone that has no rival. It’s also extremely expensive, retailing for $1,599.

But the S20 won’t be the only high-end handset hitting stores this spring, and a much cheaper flagship is right around the corner. The OnePlus 8 series is also expected to rock the same Snapdragon 865 chip, but the new OnePlus phones will be a lot cheaper than Samsung’s without sacrificing performance. In fact, we have a brand new leak that lists the main specs of the purported OnePlus 8 models the Chinese vendor is about to unveil.

Word on the street is that OnePlus will unveil its newest phones in March or April. If that’s the case, more leaks will drop, which is a clear sign that a new phone series is incoming. OnePlus had already announced one of the tentpole features of the OnePlus 8 series – its 120Hz display – even before Samsung had a chance to unveil its own 120Hz screen tech for the Galaxy S20. But that’s about all we know about the upcoming handsets.

An online retailer whose track record can’t be verified posted listings for all three OnePlus 8 phones expected from OnePlus this spring: the Lite model, the standard model, and the Pro, complete with specs:

OnePlus 8 Lite

  • 6.4-inch AMOLED punch-hole display with 90Hz refresh rate
  • MTK Dimensity 1000 Octa-core Soc
  • Triple Rear cameras: 48MP+16MP+12MP, a 16MP Sony IMX471 selfie camera.
  • 8GB LPDDR4X RAM
  • 128GB/256GB UFS 3.0 storage
  • 4,000 mAh battery, Warp 30W fast charging
  • OxygenOS 10 base on Android 10 OS

OnePlus 8

  • 6.55-inch AMOLED FHD+ punch-hole display with 90Hz refresh rate
  • Qualcomm Snapdragon 865 5G SoC, with Adreno 640 GPU
  • Triple Rear cameras: 48MP+16MP+2MP, a 32MP Samsung GD1 selfie camera
  • 6GB/8GB/12GB LPDDR5 RAM
  • 128GB/256GB UFS 3.0 storage
  • 4,000 mAh battery, Warp 30W fast charging
  • OxygenOS 10 base on Android 10 OS

OnePlus 8 Pro

  • 6.5-inch AMOLED FHD+ punch-hole display with 120Hz refresh rate
  • Qualcomm Snapdragon 865 5G SoC, with Adreno 640 GPU
  • Triple Rear cameras: 60MP+16MP+13MP, 32MP Samsung GD1+ToF 3D dual selfie camera
  • 8GB/12GB LPDDR5 RAM
  • 128GB/256GB UFS 3.0 storage
  • 4,500 mAh battery, 50W Super Warp fast charging
  • OxygenOS 10 base on Android 10 OS

Assuming these specs are real, the three phones will be virtually identical in terms of performance. However, the bigger OnePlus 8 Pro model will be the only phone to feature a 120Hz display, and the only handset to feature a 4,500 mAh battery with faster 50W wired charging. The OnePlus 8 Lite, meanwhile, will be the only handset of the three to ship with a MediaTek flagship CPU, the new Dimensity 1000, instead of the Snapdragon 865. The phone will also be the only one to have slower DDR4X RAM instead of the brand new DDR5 memory. When it comes to the camera experience, the Pro is expected to feature better sensors as well.

If there’s one thing missing here, it’s wireless charging support. Several reports said recently that the OnePlus 8 phones will be the first OnePlus handsets to support wireless charging. Then again, this is just a leak and should be treated accordingly. Giztop may have very well populated its listing pages with placeholder information just so they wouldn’t be blank, and may not actually have any inside information on the matter.



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HQ Trivia is dead as app shuts down and all employees are fired

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The company behind HQ Trivia, the live-action quiz app that let users win real money, has announced it’s shutting down.

HQ Trivia hit its peak in 2017 and was named App of the Year by TIME Magazine as millions of people tuned in twice a day for the chance to win real money.

Over time, users began to fall away and the app struggled as a result.

And last week, all 25 full time employees working at the parent company HQ were told the app was closing and they were all being laid off.

‘We received an offer from an established business to acquire HQ and continue building our vision, had definitive agreements and legal docs, and a projected closing date of tomorrow, and for reasons we are still investigating, they suddenly changed their position and despite our best efforts, we were unable to reach an agreement.’ CEO Rus Yusupov said in a memo to staff.

‘Unfortunately, our lead investors are no longer willing to fund the company, and so effective today, HQ will cease operations and move to dissolution.’

The basic idea of HQ Trivia was that it’s a free app with live gameshows that happen at set times every day (usually twice or three times). Players tune in to the show, can interact with other players via the chat function, and follow and answer the questions as the presenter tells them.

Questions start easier, and gradually increase in difficulty as the game goes on. If a player answers all twelve questions correctly they win the money. If more than one person wins, the money is split.



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You Can Now Rickroll Your Fortnite Friends

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If you win at Fortnite it’s standard practice to troll your opponents. Because they’re losers. And now you have a new way to troll your Fortnite friends and enemies, thanks to the new Never Gonna emote. Yes, Rickrolling is still alive and well in 2020.

What Is Rickrolling?

Younger readers may not be familiar with Rickrolling, because the phenomenon peaked a decade ago. However, it still pops up every now and then. And even if Rickrolling has died down, people are still fond of Rick Astley and his song, Never Gonna Give You Up.

That song is the basis of Rickrolling, which is a classic bait and switch. To Rickroll someone, you pretend you’re linking to something amazing, but actually link to the YouTube video for Never Gonna Give You Up. A cheesy pop song first released in 1987.

How to Rickroll Your Fortnite Friends

While Rickrolling may have peaked around 2008, it’s getting a new lease of life in Fortnite. This is thanks to Epic Games launching a new emote called Never Gonna. And Epic Games even Rickrolled Fortnite players on the official Fortnite Twitter account.

The Never Gonna emote literally Rickrolls your opponents. Once triggered, your character will do Rick Astley’s infamous dance from the music video for Never Gonna Give You Up. And the actual song will play in the background, complete with Astley’s vocals.

You can buy the Never Gonna emote from the Fortnite item shop for 500 V-bucks. Which is about US$5. Even Rick Astley himself is promoting the emote on Twitter, but his warning to “grab it while you can” means it may not be available for long.

Everything You Need to Know About Fortnite

Rickrolling may not be the most up-to-date meme around, but it is a timeless classic. Hence why it can be employed in Fortnite. And if you’re old enough to remember Rick Astley being in the charts, here’s everything you need to know about Fortnite.

Image Credit: Alterna2/Flickr

Read the full article: You Can Now Rickroll Your Fortnite Friends



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