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Cake day: July 2nd, 2023

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  • From an urban planning perspective, there are some caveats to your points:

    A new downtown would make a subway very easy and cheap to build, you could cut and cover instead of tunnelling

    Cut-and-cover will make shallow underground tunnels cheaper to construct in almost all cases irrespective of building in an old city center or as part of building a new city center from scratch. In fact, older pre-WW2 cities are almost ideal for cut-and-cover because the tunnels can follow the street grid, yielding a tunnel which will be near to already-built destinations, while minimizing costly curves.

    Probably the worst scenario for cut-and-cover is when the surface street has unnecessary curves and detours (eg American suburban arterials). So either the tunnel follows the curve and becomes weirdly farther from major destinations, or it’s built in segments using cut-and-cover where possible and digging for the rest.

    Cheeeaaap land for huge offices, roads, and even houses

    At least in America, where agricultural land at the edges of metropolitan areas is still cheap, the last 70 years do not suggest huge roads, huge offices, and huge house lead to a utopia. Instead, we just get car-dependency and sprawl, as well as dead shopping malls. The benefits of this accrued to the prior generations, who wheeled-and-dealed in speculative suburban house flipping, and saddled cities with sprawling infrastructure that the existing tax base cannot afford.

    Green field is just so cheap.

    It is, until it isn’t. Greenfield development “would be short term appealing but still expensive when it comes to building everything”. It’s a rare case in America where post-WW2 greenfield housing or commercial developments pay sufficient tax to maintain the municipal services those developments require.

    Look at any one municipal utility and it becomes apparent that the costs scale by length or area, but the revenue scales by businesses/households. The math doesn’t suggest we need Singapore-levels of density, but constant sprawling expansion will put American cities on the brink of bankruptcy. As it stands, regressive property tax policies result in dense neighborhoods subsidizing sprawling neighborhood, but with nothing in return except more traffic and wastewater.

    Either these cities must be permitted to somehow break away from their failed and costly suburban experiments, or the costs must be internalized upon greenfield development, which might not make it cheap anymore.


  • litchralee@sh.itjust.workstoDIY@lemmy.worldGate problems
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    5 days ago

    Looking at the images you’ve attached, this appears to be an 8 ft wide by 6 ft tall fence. That’s a good amount of weight in just the wood, and there isn’t any part of the design that diagonally braces the frame, except the steel cable… which tore from its mounts.

    My layman’s view is that you absolutely need diagonal wood elements, which should only be installed after unloading the fence, either by removing the boards or by propping up the wheel-end so the frame returns to being squared. If the wheel interferes with this, remove it for the time being.

    wide wood fence with diagonal bracing

    But I think you’d still need the steel cable, and if that has broken from its originally designed mooring, then this gate is already compromised. You may have to start over with a new Adjust-A-Gate kit or repair the current one so the cable will mount to the steel parts, rather than the wood.

    I would say to rectify the diagonal supports first, before doing anything with the hinges, since if the hinges were actually the root problem, this gate would have already fallen over. That said, it seems to me that such a wide gate might have called for more substantial hinges.

    The other commenter’s suggestion to consider a pair of less-wide gates is also sound, if the goal is a minimal-fuss gate that will last at least a decade of additional sagging and weather.



  • commercial appliances didn’t take any stand-by measures to avoid “keeping the wires warm”

    Generally speaking, the amount of standby current attributable to the capacitors has historically paled in comparison to the much higher standby current of the active electronics therein. The One Watt Initiative is one such program that shed light on “vampire draw” and posed a tangible target for what standby power draw for an appliance should look like: 1 Watt.

    A rather infamous example of profligate standby power was TV set-top boxes, rented from the satellite or cable TV company, at some 35 Watts. Because these weren’t owned by customers, so-called free-market principles couldn’t apply and consumers couldn’t “vote with their feet” for less power-hungry set-top boxes. And the satellite/cable TV companies didn’t care, since they weren’t the ones paying for the electricity to keep those boxes powered. Hence, a perverse scenario where power was being actively wasted.

    It took both carrots (eg EnergyStar labels) and sticks (eg EU and California legislation) to make changes to this sordid situation. But to answer your question in the modern day, where standby current mostly is now kept around 1 Watt or lower, it all boils down to design tradeoffs.

    For most consumer products, a physical power-switch has gone the way of the dodo. The demand is for products which can turn “off” but can start up again at a moment’s notice. Excellent electronics design could achieve low-power consumption in the milliwatts, but this often entails an entirely separate circuit and supply which is used to wake up the main circuit of the appliance. That’s extra parts and thus more that can go wrong and cause warranty claims. This is really only pursued if power consumption is paramount, such as for battery-powered devices. And even with all that effort, the power draw will never be zero.

    So instead, the more common approach is to reuse the existing supply and circuitry, but try to optimize it when not in active operation. That means accepting that the power supply circuitry will have some amount of always-on draw, and that the total appliance will have a standby power draw which is deemed acceptable.

    I would also be remiss if I didn’t mention the EU Directives since 2013 which mandate particular power-factor targets, which for most non-motor appliances can only be achieved with active components, ie Active Power Factor Correction (Active PFC). While not strictly addressing standby power, this would be an example of a measure undertaken to avoid the heating caused by apparent power, both locally and through the grid.



  • How were you measuring the current in the power cable? Is this with a Kill-o-watt device or perhaps with a clamp meter and a line splitter?

    As for why there is a capacitor across the mains input, a switching DC power supply like an ATX PSU draws current in a fairly jagged fashion. So to stabilize the input voltage, as well as preventing the switching noise from propagating through the mains and radiating everywhere, some capacitors are placed across the AC lines. This is a large oversimplification, though, as the type and values of these capacitors are the subject of careful design.

    Since a capacitor charges and discharges based on the voltage across it, and because AC power changes voltage “polarity” at 50 or 60 Hz, the flow of charge into and out of the capacitor will be measurable as a small current.

    Your choice of measuring instrument will affect how precisely you can measure this apparent power, which will in-turn affect how your instrument reports the power factor. It can also be that the current in question also includes some of the standby current for keeping the PSU’s logic ICs in a ready state, for when the computer starts up. So that would also explain why the power factor isn’t exactly zero.



  • litchralee@sh.itjust.workstoCrappy Design@sh.itjust.worksRNOP ADLH
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    8 days ago

    Agreed, it’s a very bad design. If your school speed limit covers most of the daylight hours on weekdays, is the implicit suggestion that it’s fine to drive faster on weekends and during nighttime? The street should be rebuilt to enforce the desired speed limits, not with paint or signs.

    Oh, we’re talking about the letters on the glass. My bad lol



  • A few months ago, my library gained a copy of Cybersecurity For Small Networks by Seth Enoka, published by No Starch Press in 2022. So I figured I’d have a look and see if it it included modern best-practices for networks.

    It was alright, in that it’s a decent how-to guide for a novice to set up sensible, minimum network fortifications. But it only includes an overview of how those fortifications work, without going into the additional depth needed to fine-tune or optimize them for specific environments. So if the reader has zero experience with network security, it’s a worthwhile read. But if you’ve already been operating a network with defenses for a while, there’s not much to gain from this particular text.

    Also, the author suggests that IPv6 should be disabled, which is a terrible idea. Modern best-practice is not to pretend IPv6 doesn’t exist, but to assure that firewalls and other defenses are configured to handle this traffic. There’s a vast difference between “administratively reject IPv6 traffic in/out of the WAN” and “disable IPv6 on all devices and pray no one ever connects an IPv6-enabled device”.

    You might have a look at other books available from No Starch Press, though.



  • Other commenters addressed some of the possible clearance issues, where a wider tire might interfere with the frame. But it seems to me that the discussion on tire/rim compatibility can be fleshed out.

    To lay some background, a bicycle tire is essentially mostly a hollow rubber donut, but with the inward-facing “donut hole” walls supported instead by a pair of co-axial steel hoops, known as the beads. Thus, the beads define the inner diameter of the tire. When a tire is inflated, the air pressure will cause expansion in all directions. The tire’s beads and walls (ie casing) will hold their shape, but the air pressure will try to push the two beads apart. This is where the rim walls come into play: the rim walls prevent the beads from widening apart. With the air pressure fully contained in all directions, the wheel assembly can now support impressive loads relative to the weight of the rubber and metal.

    bicycle tire cross section

    So for a bicycle rim and bicycle tire to be compatible, the two most basic criteria must be met:

    • the tire’s bead diameter must exactly match the rim’s “seated” diameter, ie at the bottom of the rim walls
    • the beads must fit within the rim walls, being neither too narrow or too wide, such that the tire maintains its correct shape and that normal loads will not cause the beads to slip out of the rim walls

    The first criteria is a strict match, so that’s easy to check. But the second criteria has some allowance for different tire widths on a given rim, or different rims for a given tire width. We can now look at what rims you have, and whether they’re compatible with your preferred tires.

    It looks like your rims are Weinmann DP18 rims, which have a trade diameter of 700C and the narrowest part of the rim walls are 12.40 mm apart. I say “trade diameter” because no part of the rim actually measures 700 mm. Instead, rim/tire compatibility can only reliably be calculated using the ISO/ETRTO measurements, which are a pair of numbers that directly answer the two compatibility criteria from earlier.

    The first number in the ETRTO system is the inner rim width, and the second number is the bead seat diameter, both in millimeters. So your rims would be universally identified as 12-622 or 13-622, since 622 mm is the actual circumference if you put a tape measure around the rim. The first number can be 12 or 13 because 12.40 mm could round up or down. Sub-mm precision does not substantially matter here.

    Now we can look at your desired tires, which have a trade designation of 700x38c but they also give the ETRTO measurement of 40-622. Unlike rims, the trade designation does actually convey some measurable dimension of the tire, but these are irrelevant for tire/rim compatibility. See the spoiler below for more.

    fuller explanation of tire trade designations

    In this case, 700 mm is the approximate outer diameter of the tire, which is only useful if:

    • you’re setting up your bike computer’s speedometer (bigger diameter means more distance per wheel revolution)
    • or you need to calculate the wheel’s ground clearance or its clearance to the forks

    Also, 38 mm is the approximate width of the tire when inflated. This is allowed to differ from the ETRTO width, since balloon tires on MTB bikes can be substantially wider than the rim, and road bike tires can be narrower than the rim. This width is mostly only useful to check the clearance between your forks, although it’s also useful to know if you’re riding near streetcar tracks.

    Narrow tires can get caught in the groove along the tracks, whereas wider tires can glide over them. A skilled rider can navigate tracks with any tire width, but it’s still a hazard that needs to be identified and negotiated.

    So we now know the rim is 13-622 and the desired tire is 40-622. Checking the first criteria, we see that the diameters (622 mm) are a perfect match. Great! But for the width, because there is an allowable range, we need to consult a width compatibility table. Some tire manufacturers will be more permissive while others are more conservative with their published tables. And there are often separate tables for road bikes versus MTB. But these tables won’t vary too substantially in their recommendations. Here are two tables, one from Continental and another from WTB.

    Continental width compatibility table

    WTB width compatibility table

    Both tables indicate that for the 13 mm rim width column, the recommended tire widths are 18-27 mm (Continental) or 23-25 mm (WTB). Your preferred tire has an ETRTO width of 40 mm, which is way too far outside of the recommendations. So no, it doesn’t look like this tire can be safely mounted on your existing rims.

    But what would happen if you tried it anyway? We can see from the table that a 40 mm tire should normally be mounted on a rim with widths 17-27 mm. So 13 mm would mean the tire beads will be squeezed closer together than designed. This means more of the tire’s tread will be wrapped up on the sides rather than facing down at the road. This also reduces the contact patch where the tire meets the road.

    Finally, a wide tire on a narrow rim exerts more leverage that could pull the tire up and off the rim. This would happen if the bike is loaded sideways, such as leaning the bike to one side while riding straight, or when the rider leans further than the bike in a curve. The recommended values take these conditions into account, so exceeding the recommendations might still work day-to-day but fail during rarer conditions.

    My recommendation is to pursue a new set of rims that can support tire widths suitable for your new environment. As the tables show, 13 mm rims are very limiting, but 17 mm rims are very permissive. Indeed, a 17 mm rim would actually allow you to mount your preferred tires (ETRTO 40-622) and possibly your existing tires (ETRTO 25-622 ?) too, if you wanted to.

    I wish you good luck in your endeavors!


  • This reminds me of the time I happened to be at a warehouse where an industrial motor control panel was being decommissioned. In the center of the panel is a large breaker, which was dutifully opened (ie powered off) before work commenced. But bizarrely, someone in the past managed to tap power from the supply-side of the breaker for some sort of monitoring sensor inside the panel. So when that circuit was cut through, there was a loud bang and the overhead lights went out.

    No one was injured, although everyone was jumpy from the inadvertent light-and-sound spectacle. And a set of cutters gained a 12 AWG-sized (approx 4 mm^2) hole.

    I may have misremembered some details, but my takeaway as a non-electrician was to 1) never assume a breaker handle at face value, and 2) don’t assume the prior person made sane choices.





  • The thing to keep in mind is that there exist things which have “circumstantial value”, meaning that the usefulness of something depends on the beholder’s circumstances at some point in time. Such an object can actually have multiple valuations, as compared to goods (which have a single, calculable market value) or sentimental objects (“priceless” to their owner).

    To use an easy example, consider a sportsball ticket. Presenting it at the ballfield is redeemable for a seat to watch the game at the time and place written on the ticket. And it can be transferred – despite Ticketmaster’s best efforts – so someone else could enjoy the same. But if the ticket is unused and the game is over, then the ticket is now worthless. Or if the ticket holder doesn’t enjoy watching sportsball, their valuation of the ticket is near nil.

    So to start, the coupon book is arguable “worth” $30, $0, or somewhere in between. Not everyone will use every coupon in the book. But if using just one coupon will result in a savings of at least $1, then perhaps the holder would see net-value from that deal. In no circumstance is KFC marking down $30 on their books because they issued coupons that somehow total to $30.

    That said, I’m of the opinion that if a donation directly results in me receiving something in return… that’s not a donation. It’s a sale or transaction dressed in the clothes of charity. Plus, KFC sends coupons in the mail for free anyway.


  • Notwithstanding the possible typo in the title, I think the question is why USA employers would prefer to offer a pension over a 401k, or vice-versa.

    For reference, a pension is also known as a defined benefit plan, since an individual has paid into the plan for the minimum amount will be entitled to some known amount of benefit, usually in the form of a fixed stipend for the remainder of their life, and sometimes also health insurance coverage. USA’s Social Security system is also sometimes called the public pension, because it does in-fact pay a stipend in old age and requires a certain amount of payments into the fund during one’s working years.

    Whereas a 401k is uncreatively named after the tax code section which authorized its existence, initially being a deferred compensation mechanism – aka a way to spread one’s income over more time, to reduce the personal taxes owed in a given year – and then grew into the tax-advantaged defined contribution plan that it is today. That is, it is a vessel for saving money, encouraged by tax advantages and by employer contributions, if any.

    The superficial view is that 401k plans overtook pensions because companies wouldn’t have to contribute much (or anything at all), shifting retirement costs entirely onto workers. But this is ahistorical since initial 401k plans offered extremely generous employer contribution rates, some approaching 15% matching. Of course, the reasoning then was that the tax savings for the company would exceed that, and so it was a way to increase compensation for top talent. In the 80s and 90s was when the 401k was only just taking hold as a fringe benefit, so you had to have a fairly cushy job to have access to a 401k plan.

    Another popular viewpoint is that workers prefer 401k plans because it’s more easily inspectable than a massive pension fund, and history has shown how pension funds can be mismanaged into non-existence. This is somewhat true, if US States’ teacher pension funds are any indication, although Ontario Teacher’s Pension Plan would be the counterpoint. Also, the 401k plan participants at Enron would have something to complain about, as most of the workers funds were invested in the company itself, delivering a double whammy: no job, and no retirement fund.

    So to answer the question directly, it is my opinion that the explosion of 401k plans and participants in such plans – to the point that some US states are enacting automatic 401k plans for workers whose employers don’t offer one – is due to 1) momentum, since more and more employers keep offering them, 2) but more importantly, because brokers and exchanges love managing them.

    This is the crux: only employers can legally operate a 401k plan for their employees to participate in. But unless the employer is already a stock trading platform, they are usually ill-equiped to set up an integrated platform that allows workers to choose from a menu of investments which meet the guidelines from the US DOL, plus all other manner of regulatory requirements. Instead, even the largest employers will partner with a financial services company who has expertise on offering a 401k plan, such as Vanguard, Fidelity, Merrill Edge, etc.

    Naturally, they’ll take a cut on every trade or somehow get compensated, but because of the volume of 401k investments – most people auto-invest every paycheck – even small percentages add up quickly. And so, just like the explosion of retail investment where ordinary people could try their hand at day-trading, it’s no surprise that brokerages would want to extend their hand to the high volume business of operating 401k plans.

    Whereas, how would they make money off a pension fund? Pension funds are multi-billion dollar funds, so they can afford their own brokers to directly buy a whole company in one-shot, with no repeat business.


  • Almost. By virtue of being a smaller antenna, the 30 cm panel does not focus its energy as tightly as a larger (eg 60 cm) antenna. Likewise, a smaller antenna does not pick up (ie receive) as much energy as a larger antenna does. Thus, by using a 30 cm panel, less of the high energy from the opposite radio will reach the receiver, and that keeps the receiver from being damaged.

    In RF engineering, there is a careful balance between output power, antenna size/shape, environmental conditions, and desired link quality. Whoever built the radio link originally did not apparently perform the necessary calculation. I’m not an RF engineer, but for spanning a mere 50 meters, this 20 cm antenna with built-in radio should be more than sufficient for a basic link.


  • Normally, increased RF power is helpful to overcome interference or noise. Just like how normally, an automobile or airplane will be easier to operate if it has a bigger engine with more power.

    At some point, though, the extra RF or engine power is no longer beneficial but also isn’t harmful. And if you go significantly beyond that, then you end up in a region where the extra power is downright harmful and is actively working against you.

    Consider an automobile driving in a rainstorm. Having more power is bad, because the tires can lose grip more easily, leading to a crash. In an airplane that has gotten into a stall, applying power is the wrong solution and just aggravates the stall, which is not good.

    Here, adding more RF power is just cooking the other receiver like it’s a Thanksgiving turkey. The extra power is no longer helpful for making communications, and may be physically damaging the receiver.


  • Although copyright and patents (and trademarks) are lumped together as “intellectual property”, there’s almost nothing which is broadly applicable to them all, and they might as well be considered separately. The only things I can think of – and I’m not a lawyer of any kind – are that: 1) IP protection is mentioned vaguely in the US Constitution, and 2) they all behave as property, in that they can be traded/reassigned. That’s it.

    With that out of the way, it’s important to keep in mind that patent rights are probably the strongest in the family of IP, since there’s no equivalent “fair use” (US) or “fair dealing” (UK) allowance that copyright has. A patent is almost like owning an idea, whereas copyright is akin to owning a certain rendition plus a derivative right.

    Disney has leaned on copyright to carve for themselves an exclusive market of Disney characters, while also occasionally renewing their older characters (aka derivatives), so that’s why they lobby for longer copyright terms.

    Whereas there isn’t really a singular behemoth company whose bread-and-butter business is to churn out patents. Inventing stuff is hard, and so the lack of such a major player means a lack of lobbying to extend patent terms.

    To be clear, there are companies who rely almost entirely on patent law for their existence, just like Disney relies on copyright law. But type foundries (companies that make fonts) are just plainly different than Disney. Typefaces (aka fonts) as a design can be granted patents, and then the font files can be granted copyright. But this is a special case, I think.

    The point is: no one’s really clamoring for longer parents, and most people would regard a longer exclusive term on “ideas” to be very problematic. Esp if it meant pharmaceutical companies could engage in even more price-gouging, for example.