Senior Members
  • Content count

  • Joined

  • Last visited

Community Reputation

7 Neutral

About druS

  • Rank

Profile Information

  • Favorite Area of Science

Recent Profile Visitors

1285 profile views
  1. Flood-related engineering...

    Or the building is old and built to old standards. Or they had not worked to best practice modern design. Or the US is behind in building standards. Or they the systems worked which is why emergency teams were there etc etc . Who knows. Having an emergency does not in itself mean a failure of design. The 1:100 benchmarks should be under review pretty much everywhere - a basic tool of adaptation. Though in my experience it tends to happen through Green Building Ratings Systems - such as LEEDS in the US. Legislation and the Standard writers tend to lag the latest thinkers such as adaptation measures in LEEDS (or GreenStar in Australia, or BREAM in the UK). Generally (as I mentioned) this particular issue would be handled through entries to the basements rising to a 1:100 (or other design) level before ramping down. But it won't stop every eventuality. On the whole there have been few experiences like the one under discussion. Not something that is going to suddenly impact building standards around the globe. Where say, something like Grenfell Tower fire in London - certainly impacting local building standards here in Sydney, and I suspect a rolling impact around the world.
  2. Flood-related engineering...

    Building rules on lifts (elevators) differ around the world, I speak from experience in Australia and the UK - not USA. Cell/Mobile reception Lift cars can and are sometimes made of glass. The core that lifts sit inside are mostly made of structural concrete, though sometimes lightweight infill cores are used. Generally it is a matter for efficiency of structural engineering and you would lose an aweful lot of space to sit the lift outside of the shaft. This is sometimes done in lobbies etc where a steel structure is used with glass, and a glass lift car. You can then see through. But that does not necessarily give you mobile/cell reception. External glass curtain walls contribute most of the interference issue to mobile/cell reception in city towers. This is overcome by DAS (Digital Antennae System) systems - essentially a repeater system plugged into cable and distributed through the building. Most Premium grade buildings are briefed to maintain reception in lift cars (granted that from personal experience it is not easy to achieve 100%). But mobile/cell is not an emergency call out system. Lifts are required to have handsets which call back to a central point - generally the lift service provider. AND a stopped lift should be noted back in the control system anyway so that a call out should be alerted. "Airholes"/Lift Shaft ventilation This generally depends on the size of shaft and speed of the lift, but most lift shafts will have vents to reduce pressure build up as the cars move up and down. It isn't really for fresh air for human breathing - there should be enough air in a shaft that this is not a problem anyway. Lift "flood measures" The lift pit will generally have a sump which in normal circumstances should be dry. You would normally expect a float system in that sump that is linked to the building control system. This is primarily for equipment protection, but should also set off alarms in this scenario. I note that far and away the most likely reason behind lift shaft flooding is a burst pipe or some similar internal issue. And this too should have already alerted on the building control systems. External flooding would be something you would expect the building management to step in on. Though if this is "flash" flooding possibly not quick enough. But someone should know what is going on and be calling in assistance. In flood prone areas, design would usually involve unseen barriers at street level to keep extrernal water out on the basements - up to a limit anyway. If there is catastrophic flash flooding you wont keep the water out. As others have said, it isn't common. In general existing building design and should be enough, if implemented reasonably.
  3. We seem to have forgotten about the quoll. I've never sighted one in the bush (not for want of looking in areas they are meant to exist) and wish the researchers all the best in their endeavours.
  4. D Block electron arrangements

    Loving it - plenty for me to cogitate here. Give me a moment or two. Thanks so far hyper
  5. D Block electron arrangements

    Hypervalent_iodine - thanks - i did expect responses that required more thinking on my part! 1. Can we start with why the d-block electron arrangement is 3d in the fourth period. 2. Thence to the specifics with Cr and Cu. In this case the stability issue seems like an observation rather than information behind why it is this way. Full valence electrons create a stable arrangement before we consider the d block. SOmething changes here where all of a sudden there is stability mid-period. 3. The exact cause can get fairly involved. I guess that I want to nudge that issue. Maybe I don't know enough to follow, but at the moment I haven't been able to find anything. Note that I have posited this thread under chemistry - I'm hoping to not end up too deep in quantum. 3. With Fe I need to look at the orbital diagrams or electronic configurations? Does that not take us back to my initial query? Perhaps though this is something that is not what I have learned yet? I'm comfortable with electron configuration up to Argon, and the step through d block doesn't look that hard. But maybe I'm missing something? Cheers Dru
  6. I'm between study periods at the moment and have gone back to something that I noted as interesting during the last study period. Here is a quote: "...the transition metals have the general configuration [Ar]4s23dn except chromium (4s13d5) and copper (4s13d10). The reasons for these exceptions are complex" [Zumdahl et al - Introductory Chemistry: A Foundation] ps I had to edit the super scripts and trust I have it correct. Digging through the various web based tutorials I can work out writing the electron configurations (with cheat notes) but so far nothing to explain why, just "it gets complex". The half shell and complete shell being stable isn't really it either - why is that? OR at least what is the background? Why are the electron configurations for Cu and Cr the way they are? It would be great if I could grasp, or at least be a little clearer, why and when Fe forms the cation iron(II) or iron(III). Let alone what is going on in something like Fe3O4. [I believe a mix of iron(II) and Iron(III) is happening but have no logic behind it.] How does this relate to the concept of noble metals? Why are Cu, Ag and Au noble, but Zn, Cd and Hg not always considered noble?
  7. Confused about resonance structures

    studiot, I doubt I am the only one who wont miss your posts. Plenty goes over my head, but I learn a little bit every time. It is never imo wasted effort.
  8. Scaling up a chemical process

    I am utterly astonished that there was no form of back up cooling. Astonished. Likewise at construction standards in the control room which I would hope would be designed as a safe house under emergency conditions.
  9. beecee This force, I couldn't follow where it is. Between the quarks, or inside the quarks?
  10. humans

    I'm astounded that you haven't seen a funnel web. And I wont run through sharks as it is a thing that perhaps I will cut across more often than people who don't spend much time on the water. Nor how far south irukaji actually travel. In the mean time - can't see how it impacts the human genome, which is where we started.
  11. humans

    Where I sit in Sydney (potentially) lethal animals it would be statistically high that you could meet within 100m would be a very small number of spiders. Fatality rate unlikely to be high though, certainly with modern medicine. In the harbour of course there are untold species of sharks, though realistically only the bull shark should be considered an actual risk. Further north in Brisbane you'd add the deadly brown snake, and in outer suburbs Taipan, red belly black etc. North again add the salty (crocodile), irukanji (and a small number of other jellyfish), add tigers and hammerheads (sharks). Continue north to add cassowary if you are foolish enough to disturb a male on a nest or protecting young. BUT at that point we have strayed, no deviated completely into the world of infotainment. Add a throbbing sound track and an American accent commentary along the lines of "a wild boar on three legs gorged my brother!". You'll find it on fox and time of the week. None of this has any statistical chance of impacting human evolution. In the mean time as a subjective observation from living here for decades, our gene pool now has statistically a much higher influence from the people of Asia, people live longer and are more healthy. Our rate of natural population increase is steadily on a downtrend, made up by migration. People stay in education longer. Technology in our lives seems on an exponential increase. Also note that the first nations of Australia lived here during the time of the mega fauna. Giant crocodiles, giant carnivorous kangaroos, giant wombats that followed annual migration patterns following annual rains through the grasslands of internal Australia. (WHich had already changed form the rainforests of Gondwanaland with plenty of earlier species that did not adapt.) These species failed to adapt quickly enough to the drying of the continent and no longer exist. The only megafauna left today would be the salty, emu, cassowary, possibly the grey kangaroo (at 6 feet tall). And the introduced camel. The first nation people adapted and survived. Differences to the extinct mega fauna? Surely agility, adaptability, resilience, mobility and intelligence.
  12. What is science?

    The definition I have is: The system of observation and experimentation (the scientific method) to discover the laws which govern the universe; and the body of knowledge resulting from this system. I would add that by it's very nature it is empirical not metaphysical. Step to philosophy if you wish to go there. But honest, where are you going?
  13. swimming on Titan

    I've been wondering about similar topics, so hope this is not considered off-topic. How would wind and waves on Titan compare to Earth. Instead of swimming how would sailing be effected? PS: Gian - if this is too far astray from your query let me know I'll start something else.
  14. An engineer's view: It's not really a question of thermodynamics, I suspect. And it's not just relative. I think you want to know more about the humidity of the air, and the air movement. Relative temperature will have an impact, but not as much as humidity and wind. Then add in sea spray. Which means I'm with mistermack.
  15. resonating electricity from sea wave

    I wasn't sure how to explain it but as usual studiot you are all over it. The power of a wave in the ocean decreases quickly with depth. Until the bottom is closer and you create surf. I would think, no more than gut feel, power from waves is likely to be low efficiency for power production.