skewbone

Those questions don't allow for the possibility of installing louder exhausts for non-psychoanalyzable reasons... There are also degrees of loudness.

I put a slightly louder exhaust on my turbo car because the large torque jump at around 2000 rpm is/was harder to anticipate with the standard exhaust and cabin sound dampening at speed. Now the engine note is a better indicator of the impending torque jump and makes driving smoother and easier without taking my eyes off the road and onto the tachometer.

And Jer Sypult who made Climb (track 10) who is not in Sonic Mayhem!

Thanks, that's a great suggestion. Looks like I can also use QEMU to also trace MMIO. I appreciate the advice!

This would be fantastic. I'm trying to write an audio driver for my HT|Omega eClaro PCIe soundcard for Linux by leveraging kernel modules for cards with a similar BOM. It is mostly working, but the main hurdle is the inability to increase the volume to >= 50% of the volume in Windows. I'm setting attenuation correctly to the correct DAC registers and I can hear the opamp relay click on, but can't adjust the final gain. It sure would be great to have the Windows driver source. Worse yet, the company is unresponsive to my requests for any info (schematics, gain setting sequence, anything).

The PE6000 and the LM6000 are two shaft machines, where there is a low speed shaft on which sits the low pressure compressor and low pressure turbine (the hot and cold ends), and a high speed shaft on which sits the high pressure compressor and high pressure turbine. The two shafts are concentrically located, with the high speed shaft being on the outside. The low speed shaft is where the generator is coupled, and can be done on either the hot or cold end.

You're right that the core doesn't spin at synchronous speed but the LP shaft does. It's optimized for 3600rpm, but could run at other speeds... the machine just isn't designed for it. The LM6000 only uses a gearbox for 50Hz units while 60Hz don't need it.

The PE6000 is closer to a GE LM6000 rather than an LM2500. https://www.gevernova.com/gas-power/products/gas-turbines/lm...

The LM6000 and its variants have been in operation since probably the 1980s. I can ask around at work. I used to develop the code for the LM6000.

You're spot on that people use them for peaking, but it's a big mix. Peaking, mid-merit, and sometimes base load. There are low emissions versions as well, that keep NOx to a handful of ppm without using extra water.

People tend to use the inertia H constant (MW*s/MVA) when it comes to describing the amount of inertia that grid forming inverters and batteries can provide. Sometimes the units are simplified to seconds, which makes it easier to understand how many seconds it could provide rated power for this specific function.

Active inertia or synthetic inertia do vary power when frequency changes but the key is the dynamic behavior. They typically do so by emulating a synchronous machine by implementing something like the swing equation in the active power control (see REGFM_B1 [1]). They essentially emulate the inertia, which makes them have some damping in changing the phase angle and frequency of their voltage waveform just like a spinning synchronous generator would when resisting frequency changes due to physical inertia, resulting in an inertial active power response. This makes it easier for people to analyze because they understand the swing equation from synchronous generators.

[1] https://docs.nrel.gov/docs/fy24osti/90260.pdf

Would you mind sharing any pictures or video about the mower? I converted my push reel to electric without a kit, and have been considering putting separate high torque, low speed motors for drive wheel control to start moving towards autonomous cutting. Would be great to see your experience!

GE Hitachi Nuclear is hiring people for across the nuclear island, steam island, and other plant components for their SMR design.

It is a pretty exciting time for that division, so if anyone is interested, definitely look into their openings.

https://jobs.gecareers.com/power/global/en/ge-hitachi-nuclea...

https://www.gevernova.com/nuclear/carbon-free-power/bwrx-300...

Gas plants can change load in seconds by increasing or decreasing fuel flow. You can consider the generators as operating at the local grid frequency, and power being the product of torque and frequency, so they just change torque to change load, which is done through fuel control. Aeroderivative gas turbines can go from near 0 to full load in less than 30 seconds, which is obviously an eternity compared to battery system inverters with sub 150ms settling times.

You are right that load isn’t independent of frequency, though. For those who are interested, in a simplistic and hand-wavy explanation, the torque imbalance between generation and load causes a change to the frequency. The net torque = torque of generation - torque of load = I*alpha, where alpha is the derivative of omega, or the angular frequency of the grid, and I is analogous to the inertia of the grid. If there is more generation torque than load torque on a generator (and the grid), the frequency increases and vice versa. Keeping the net torque constant, increasing the inertia makes the grid frequency derivative smaller for the same imbalance between generation and load, which is why it was typically desirable to have higher inertia synchronous generators.

What you were describing around changing fuel to maintain speed is typically frequency droop, which is where generators change their power as a function of the frequency, which is a distributed scheme for all generators to independently act to drive the torque imbalance to 0, with some insensitivity proportionality constant. For example, in California, gas turbines are assigned a droop value within the range of 3 to 5%, which means a 3 to 5 % reduction in frequency should result in a 100% increase in power, and vice versa. The total power should be provided in less than 30 sec typically.

For those that are really motivated to understand the interplay between generation, load, and frequency, look up the swing equation in the context of power system stability.

There is another aspect of synchronous generators that enable them to act to stabilize frequency independently, called the inertial response, which also has to do with their rotational energy. A generator at some frequency has KE = 0.5*J*omega^2 where J is rotational inertia and omega is angular frequency. If the frequency changes, it has a change in kinetic energy = 0.5*J*(omega1^2 - omega2^2) which is equal to some power for some period of time (= P*delta_t). This shows that as a generator sees a change in frequency, the shorter the duration, the larger the amount of energy is converted to power. Essentially, generators have an inertial response that act to inject power the faster frequency is falling, and vice versa, which is a self stabilizing function for grid frequency.

This loss of synchronous inertia as generators are replaced by inverter based resources (IBRs) is why managing grid frequency stability becomes more difficult. Various techniques are used to abate the loss of inertia, including emulating the swing equation within inverters to make them behave as synchronous generators and provide that inertial response. This is typically called grid forming with virtual synchronous machine.

There's no mention of the actual electrical architecture. In the rendering, I only see modules and no DC/DC converters or inverters separate from the modules. Some of the competition uses module level inverters so maybe that's their approach as well? It's hard to tell if the 3 large conductor looking objects going down the font of the module faces (or rear?) are 3 phase AC or 2 x DC cabling + 1 comms or a fire suppressant line.

It would also be good to know what depth of discharge nets them 12,000 cycles (edit: looks like 95%)

I design control systems for grid scale battery systems that can operate as standalone power plants, or as hybrid power plants with solar, wind, or gas turbines.

Batteries essentially enable planners to increase renewable generation and make it less variable.

For gas plants, they can avoid or reduce the need to run gas turbines as peaking power plants which are typically needed to cover the significant gap between renewable generation and residential loads in the early evenings. The batteries can cover that period with energy shifted from the day to the late afternoons and early evenings.

Of course there is still CO2 emitted in their manufacturing, but I am coming from a previous career in making gas turbine control systems, so it's still an improvement. I'm trying to make the broadest impact I can as an engineer.

Does this impact Google apps (or whatever their grandfathered personal email hosting/google drive is called now)? I hope it's just the registration component, but I think I should plan the move to another email/file sharing provider.

EDIT: Looks it is answered here. We become customers of squarespace for that too, so I doubt it will be free after this. Time to plan the move. https://support.google.com/domains/answer/13689670

Turns out it was STS120, launching the Harmony module on Oct. 23, 2007.

I was working at a facility where we tested gas turbines and spent a good amount of time studying combustion acoustics. The best way I could describe the feeling standing near the water for the shuttle launch was feeling a continuous combustion pressure hitting my chest. Pounding wasn't the best choice of words.

Rocket launches feel the same way. I got to see STS121 launch from the VIP area at Kennedy Space Center a couple of years back, and it felt like a continuous pressure wave pounding on my chest until the rocket was above the clouds. Crazy feeling.

There are two different types of state machines that behave differently. Moore machines have actions (or outputs) determined by the state while Mealy machines have actions determined by the specific transitions (or state + inputs).

Depending on the system and implementation constraints one type works better than the other (e.g. Mealy machines can implement Moore machine behavior with one less state, which may save hardware).

I agree with this.

You also don't know the exact mix of sources generating the particular amount of power consumed by your data centers instantaneously. Since each generation source has it's own (complicated) emissions profile, the amount generated by different sources is necessary to compute your CO(2) impact.

A power grid can calculate it's CO2 impact of generation more easily because they only need to use emissions measurements or emissions models for the total generation plant. Most places serious about air quality opt for sensors, but CO2 isn't their most pressing measurement. Typically NO2, NO3, CO, and unburned hydrocarbons are more regulated.

If you want to make an impact to GHG, setting aside quantifying the impact, switch to a renewables-backed power supply and increase your efficiency.

There is an industry that packages high quality Sony image sensors in packages with C or Cs mount lense compatibility and native UVC support on Linux/MacOS/Windows. Primary uses seem to be industrial cameras for manufacturing quality inspections, circuit magnification for repairs, installation onto telescopes, etc.

Prices range from $40 to multiple hundreds for extremely high quality sensors.

This sketchy site has comparisons of the sensors by area and signal to noise ratio.

https://navinside.ru/tablitsa-sravneniya-sony-snr1s/

I bought a 1080P one with very high SNR and 2-14mm lens using the Sony IMX291 sensor for $79.

Arducam 1080P USB Webcam,... https://www.amazon.com/dp/B0991XRFXB?ref=ppx_pop_mob_ap_shar...

For audio, I bought a Samson Q2U USB/XLR mic for $60. USB has been perfect, and the included stand works fine to the side of my keyboard.

Samson Technologies Q2U USB/XLR... https://www.amazon.com/dp/B001R747SG?ref=ppx_pop_mob_ap_shar...

Altogether, this is a cost effective way to increase audio and video quality for meetings / streaming.

Does anyone know if there is a limit on the number of users with this free option?

I agree with you on the gas peakers comment.

Peaking power plants are typically used to provide the extra electricity needed when the supply of renewables start to fall off in the evening and the increased demand from HVAC and other loads coincide. They ramp fast (or start in a spinning reserve mode) to supply power in 5 to 10 mins. Nuclear plans can ramp but they're not really designed to ramp to replace all of the gas peakers.

Another issue is that the grid requires a certain amount of connected inertia in order to resist changes in frequency. Imbalance between generation and loads will lead to frequency changes. Frequency changes can affect motors, fans, negatively (over fluxing leading to premature failure), so there are typically protection systems that disconnect loads or generation outside of a nominal frequency band. Renewables compound this problem because they are variable (generation fluctuates), and because they are inverter based and provide no physical inertia. Therefore, as you increase renewables only, you see greater problems with frequency stability.

To combat the frequency issues today, you use more agile generators (typically gas) that can provide some inertia but also do fast power changes to arrest changes in frequency and restore system frequency (see primary frequency response).

It's hard to see how turning off all gas and displace it with nuclear will work unless you expect nuclear to provide all of the primary frequency response, which includes needing to both increase AND reduce power to stabilize frequency. Large nuclear plants with high inertia generators on their steam turbines do help keep frequency more stiff though, so that's helpful.

If you were to use nuclear to replace gas, you'd also need to make them fast ramping to manage variable renewables. Or you could retain some gas to be the variable load management units, but then you'd basically be keeping gas peakers.

Alternatively, if there is greater adoption of energy storage to help make renewables more dispatchable with more predictable power, that solves part of the frequency issue. I believe gas peakers typically run for under 4 hours a day, so 4 hour duration energy storage would be effective at retiring a lot of the gas except for that kept available as emergency power plants during disasters or weather events.

Part of the frequency and inertia problem will also get solved in the next decade or so. Generators provide an electrical response to the rate of change of frequency that serves to stabilize frequency called the inertial response. Essentially, the change in kinetic energy from one rotational velocity to a lower one results in an uncommanded power injection into the grid. This power injection then counteracts the lack of generation that led to the initial drop of frequency. Inverters are starting to get deployed with grid forming capability in which they can provide synthetic inertia, and over the next decade could reduce the need for synchronous inertia.

It's not an easy problem to solve so I always take sweeping recommendations with a grain of salt.

(I have been doing control system design for gas turbines, batteries, and renewable/thermal/battery hybrid systems for 15 years).

It doesn't address the criticism from many legacy Google Apps users using custom domain email and drive / calendar for our families.

It would be great if they would at least provide a reasonably priced option. I don't mind paying, but paying $7/mo per account just seems like they're ignoring personal use rather than business use.

I'd be willing to pay $10 or $15/mo for up to 10 personal accounts.

Graphviz ships with a tool called dotty that can be used for visual graph editing. It's a bit cumbersome but does work.

https://www.graphviz.org/pdf/dottyguide.pdf

Edit: I don't know of a really good visual tool as I've found text editing .dot files directly with a live visualization pretty nice. I use graphviz pretty regularly.

I got one of these before going to university. Abit BP6, dual Malaysian C300a overclocked to 450 MHz on the slotkets, an ATI Rage 128, an SB Live, all sitting in an Inwin Q500 case. I was chasing the SMP dream to try it in Quake 3.

I donated the machine to a Goodwill store a few years ago before realizing there's a retro scene who would've appreciated it more.

Thanks for the nostalgia trip!

There are other players in the modular utility scale energy storage space. GE and Fluence are two examples.

https://www.ge.com/renewableenergy/hybrid/battery-energy-sto...

https://fluenceenergy.com/