At my local pair of stores (Home Depot and Lowe's across the street), it's the Lowe's lot that has a Flock camera on every entrance.
145 karma · joined November 24, 2024
I have to disagree with that. Almost every time I've been called in to rescue a frustrated novice at the soldering bench (which has happened a lot), I've found them using the thinnest tip they could find with the temperature cranked to 400°C or higher because nothing was melting. It's fine to have an iron that can exceed 400°C (and I can't think of any I've used that couldn't), but that capability should be rarely used.
A heavier tip -- generally the heaviest that will fit between obstacles on the board -- at a lower temperature is much more forgiving.
The small tip has little heat capacity, significant resistance between the thermal reservoir (the heavy body of the tip) and the contact point, and usually very little contact area with the work. That makes the temperature at the joint highly sensitive to tip position, surface contamination, and copper geometry on the PCB. A thick trace or ground plane connection sinks heat from the joint so well that it will never melt, but a small pad on a thin signal trace will quickly get hot enough to detach the pad. Gunk on the board or oxidation of the tip adds more variability. And the high idle temperature makes for fast oxidation of the solder coat on the tip and then the plating, which creates more problems and frustration when you're new and don't recognize those symptoms.
A fat tip provides a large thermal reservoir right at the contact point and usually creates a larger contact area that's less disturbed by a bit of contamination. The much lower thermal resistance brings the joint temperature closer to the iron's thermostat setting, allowing you to keep that setting lower -- I'll go as low as 300°C for SnPb on a not-too-heavily-coppered board, maybe up to 350°C for lead-free. That gives you consistent heating of a wide range of targets and is much less likely to lift pads even with the long dwell times that often happen while a novice is learning. At the low end, it slows tip oxidation enough to make it almost a non-issue. And less flux charring means less gunk on the board to interfere with the next joint.
Predictability makes the whole learning process much smoother, and running small tips at high temperatures creates all sorts of issues that are hard to see or understand until you've got some experience behind you. When in doubt, use more copper before using higher temperature.
There's still a strong angular dependence in the reflection amplitude; 1/r^2 fall-off does not imply isotropic distribution.
Because the power returned to the antenna scales as the -4th power of the distance to the target, and detection depends on that power being greater than some threshold. If the fourth power (rather than the square) is surprising, think of the reflection as re-transmitting the power that arrived at the target. The incident power on the target goes as RCS/r^2, and the power that makes it back to the original antenna gets another factor of 1/r^2, so the return scales as RCS/r^4.
(a) I felt speed was far more important than readability (reasonable for rapid-fire short messages or constrained typing ability such as a flip phone, also a common way to imply "fuck you, my time is more important than yours" in longer forms such as email), or
(b) i'm 14 and e e cummings is so deep (blogs)
Yup. From the device description in its decommissioning plan:
The CFX was a sub-critical assembly of uranium-2-35 surrounding a Cf-252 source. The function of the U-235 fuel was to multiply the neutrons coming from the Cf-252 source, which fissions spontaneously. The CFX was designed never to exceed a Keff of 0.99. The CFX assembly yielded sufficient neutron fluxes for applications such as neutron activation analysis.
I'm not sure how the progress of institutional and amateur observations compare. Obviously the big guys benefit from the same technological advancement, but I don't know whether the fraction of new objects discovered by amateurs has been growing or not. I suspect the odds of the first interstellar object being found by an amateur were still pretty long.
By my back of the envelope math, burning 600000 kcal should produce couple hundred kg of CO2. You could also make that crossing in less than a third of the time under sail, with about a third of the daily calorie consumption, for maybe a tenth of the CO2 output.
Oh how the mighty have fallen. I've only worked on one major project with a Microchip MCU (PIC32MK), but their documentation and support were terrible. No detailed documentation, just a driver library with vague, sketchy API docs and disgustingly bug-ridden code. Deadlocking race conditions in the CAN driver, overflow-unsafe comparisons in timers, just intern-level dumbassery that you couldn't fix without reverse engineering the undocumented hardware. Oh, and of course what documentation did exist was split into dozens of separate PDFs, individually served, many of which were 404 unless you went hunting for older versions or other chips in the product line. It certainly cured me of any desire to touch another Microchip product.
But when I did go past the required courses and into math for math majors, things got a lot better. I just didn't find that out until I was about to graduate.
Right?! In my path through the physics curriculum, this whole area was presented in one of two ways. It went straight from "You don't need to worry about the details of this yet, so we'll just present a few conclusions that you will take on faith for now" to "You've already deeply and thoroughly learned the details of this, so we trust that you can trivially extend it to new problems." More time in the math department would have been awfully useful, but somehow that was never suggested by the prerequisites or advisors.
Are you talking about the 90s or now? Because those were all at least as true then as now. Everything took forever. You needed more RAM every month. Everything crashed constantly. I had to reinstall Win98SE so many fucking times that I can still type F73WT-WHD3J-CD4VR-2GWKD-T38YD from memory.
The amount of suck in commercial software is constant. Companies always prioritize adding the shiny-looking features that sell software to rubes over improving things like memory use, response time, and general quality of life until the quality of life is actually bad enough to drive customers to another vendor, so it's perpetually bad enough to keep the average customer right on the edge of "oh fuck this, I'm switching to something else."
SpaceX's advance was going from oxygen rich (where all of the oxidizer and a fraction of the fuel run through the preburner and turbine, as used in the Soviet/Russian engines) or fuel rich (vice versa, used in the Space Shuttle) to full flow (which has both oxygen- and fuel-rich preburners and all of the propellants flow through one turbine or the other).
There is one type that comes closer to a turbocharger's operation: the "tap-off cycle" runs the turbine on gas drawn from the main combustion chamber rather than using a separate combustor. Tap-off cycle engines aren't common but Blue Origin and Firefly are using them.
No, it does not. It illustrates that the portion of an atom that strongly scatters alpha particles occupies a small fraction of the atom's volume. Asserting that alpha particle scattering is the only correct definition of the threshold between emptiness and non-emptiness is an awfully strange position to take.
When interacting with other electrons at energy scales relevant to human life, i.e. maybe ten electron volts and down, an electron cloud is somewhere between solid (core electrons especially in heavy atoms) and squishy (valence electrons). Give a rock the ol' "I refute it thus!" and your toes will report that that rock's electrons are quite competently occupying their space.
Ask an alpha particle at nuclear energy scales a million times greater, and that electron cloud is like a swarm of gnats to a speeding car. The electrons only interact with the alpha electromagnetically, and it takes another object that interacts through the strong nuclear force to really bother a nucleus (most of the time).
Ask a neutrino, and it will tell you that all the nuclei in the Sun are but a wisp of fog.
This is a good example of how approximations valid in one regime fail in another but are not therefore useless. Rutherford's experiment reveals that there is more going on with matter than what can be probed by fingers and microscopes and chemical reactions, but it in no way invalidates those other observations.
The obviousness or lack thereof is subjective, but the exclusivity is firmly established. The absolute indistinguishability of particles is deeply woven into quantum mechanics; you don't get a Pauli exclusion principle without it, for example. If the particles remembered their previous lives, and an electron that used to be tied to an iron nucleus weren't completely identical to one that used to be stuck to a carbon nucleus, all of quantum mechanics as we know it would be impossible.
If some community teaches Rules of Beauty which these characters contravene and are thereby deemed ugly, that says more about the merit of such Rules than anything else.
That ampersand, though... okay. You can have that one.
Multi-junction cells beat that limit, but they're still horribly expensive to manufacture which confines them to niche uses like spacecraft.
> Create overly-ambitious timelines and set impossible-to-keep deadlines
> Send unnecessary meeting invites then cancel them last-minute
> Don't use collaborative software, just email things back and forth
> Introduce burdensome software license approval processes
> Leave off the phone or video call information from a calendar invite
Forget government, this is a summary of standard operating procedure at my last (large, private sector) employer. Maybe they weren't all idiots, they were just fighting the man.
Just like the original Simple Sabotage Manual, this is worth reading just to reflect a painfully clear image of your own organization's dysfunction (and possibly your own role in it).