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MoominPapa

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MoominPapa last won the day on January 23 2017

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About MoominPapa

  • Birthday 12/11/1964

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    CCer.

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    Computers
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    Melaleuca

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  1. From the CRT stoppages mailing list. MP. Lock 1, Top Lock to Lock 1, Top Lock on Hertford Union Canal Monday 16 September 2019 15:00 until further notice Type: Navigation Closure Reason: Water resources Original message: Following the long period of mainly dry weather, flows of water from the river tributaries that feed the Grand Union Canal remain low. This is having a direct impact on the water levels on the Paddington Arm, the Regent’s Canal, and the Herford Union Canal. Our water management team has also recorded that water is frequently being run through locks, including Hampstead Rd, overnight which is further depleting the water supply. This means that currently there isn’t enough water in central London for navigation. We have therefore taken the difficult decision to temporarily close navigation so that water levels can return to normal. The following locks will be closed from Monday 16 September 2019: Grand Union - Lock 90 Top Lock only. Regent’s - Hampstead Rd Lock 1A and 1B Regent’s – Kentish Town Lock 3 Regent’s – Mile End Lock 9 Hertford Union – Lock 1 We are monitoring the situation constantly and will reopen the locks as soon as practically possible. Our aim is to strike a balance between making the waterways as accessible as possible for boaters while mitigating against future risk and we appreciate your patience during this unprecedented time.
  2. You only need to get down to about 200K for it to be solid in a vacuum, not 0K, but the point is still valid. MP.
  3. Electric boat and steerer wearing space-suit MP.
  4. So, I just got around to reading last week's CRT boaters update, which includes the following gem. I think all the stuff about air pressure is just wrong - the air pressure changes from a boat cabin and above-water hull moving at 3mph are tiny, and anyway air pressure changes are not needed to explain changes in the water level: exactly the same water level changes would be experienced if there was a vacuum above the water. What does the team think? MP.
  5. but only on the Nene. On the Ouse you leave the exit gate(s) open, but all paddles (called "slackers" therabouts) closed. MP.
  6. The full report from the windfarm operators is in the appendicies. I couldn't make head nor tail of it, but a proper engineer probably could. MP.
  7. We've some up the Nene over the past week, and it's difficult to see which direction is upstream. The Nene can be fierce, but at the moment it's fine. It's also not too weedy, which is the main possible problem at this time of year. Join Friends of the River Nene for access to their moorings, get a copy of the EA Nene map, which shows its moorings, No. there are moorings on the Middle Level (Athy listed them) and moorings on the Ely Ouse, at least at Denver, Ten mile bank, The Ship Inn and two or three others from there to Ely. Mooring in Ely is nice, but crowded. Join GOBA for more moorings. You need to book Stanground lock in Peterborough 24 hrs in advance. Salters Lode to Denver is tidal, Talk to Paul in advance, or turn up and expect to wait up to 24 hours for the next tide. The tidal trip is half a mile, and not arduous. Lovely waterways. Enjoy! MP.
  8. The lightning strike is not being blamed, at least by the report. The blame, if any it put on the control systems at the windfarm and power station which tripped when they shouldn't have. The role of the lighting strike is to precipitate these two faults at the same time which caused the grid to e critically short of power. Had the two faults manifested themselves due to two different lightning strikes, separated in time by more than a few minutes, the load shedding would not have occurred. It's interesting that there seems to be no explanation for multiple failures at the gas station. 1) The steam turbine tripped to due to bad speed data. It looks like the theory on this is bad power to the control system as a result of the grid disturbance, but the UPS checks out OK. 2) Once the steam turbine tripped, the gas turbine tripped too, because the steam pressure was too high: the stream is supposed to be dumped direct to condenser under these conditions: it shouldn't be necessary to shut down the gas turbine too. MP.
  9. Final technical report is out. https://www.nationalgrideso.com/information-about-great-britains-energy-system-and-electricity-system-operator-eso Quick summary. Lightning strike caused system disturbance. So far, so routine. System disturbance caused windfarm to trip out. This was unanticipated, should not have occurred, and has been understood and corrected. System disturbance also caused Little Barford gas fired power station to trip out in stages. This should not have happened either, and it's not clear to me that the cause has been understood and corrected. These two events were unrelated, except that both being precipitated by the original disturbance, they happened at the same time. The grid is not designed or run to handle two major infeed failures happening at the same time without consequences. It mitigated the problem by dropping some load (power cuts) This went to plan, and kept things stable and allowed the problem to be solved over half an hour or so. The biggest disruption seems to have been on the railways, which was caused by trains which shut themselves down and couldn't be restarted. The supply to the railways was not interrupted, but the low frequency tripped the train control systems. The railway could fairly by described as much more more fragile than the Grid, no surprise there! MP.
  10. USB ports have DC-DC converters which can generate radio interference, similarly some kinds of LED and fluorescent lamps. DC motors have brushes/commutators which spark and generate radio interference. You'd have to be particularly unlucky that all three things generate enough RF at the right frequency to knacker your DAB radio, but it's at least a possibility. The "cliff edge" nature of digital radio doesn't help. It doesn't degrade gracefully, in a fringe reception area it works, or it doesn't. MP.
  11. This post cannot be displayed because it is in a forum which requires at least 10 posts to view.
  12. Oooh err, missus! MP. MomminMama says to avoid this problem in the future, you, or MrsRusty should hand wash her bras. MP.
  13. Our stove flue is somewhat "lacy" and we won't be in a position to get it replaced for a couple of weeks, so no stove for us. Expect unseasonable cold. MP.
  14. The implication of this is that Peukert's equation is irrelevant for, on average, small discharge rates, which would imply that LA works better than it actually does, in my experience. Actually, I suspect what happens is that peukert "constant" isn't, and increases as SoC is reduced. To fully discharge a LA battery therefore needs the same long, slow, asymptotic current curve as fully charging it does. (But in mirror image, as it were.) It's interesting to speculate why this effect is so much less visible in LiFePo4 cells. The mobility of Lithium ions in FePo4 is not that great, but the big difference is that the active material is in a very thin layer of tightly controlled depth, spread over a large area of current-collecting foil. The reason this works is that the charged and discharged forms of the active material have similar physical properties, so you can expect such an arrangement to be stable over many cycles. LA uses the "spongy lead" form because that's the only physical arrangement that can be expected to survive the transition between lead and lead sulphate and back again, not because it provides good access for ions in the electrolyte to the electrode material.
  15. But I like my Kalman filter MP.
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