Recent content by Nik_2213
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Why does a fan cool you in a sealed room if it adds heat?
Perhaps check out 'Wet Bulb' vs 'Dry Bulb' temperatures in addition to 'Wind Chill' ? FWIW, during thankfully rare UK heat-waves that coincided with Saharan dust incursions and dire pollen-count 'Spikes', only desk and wall-hung fans, plus big 'Air Mover' stirring stair-well, kept my wife and I...- Nik_2213
- Post #16
- Forum: Introductory Physics Homework Help
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Modelling the voltage measured across a dc motor
IMHO, there is a further issue: Is this a 'brushed' DC motor ?? Such are notoriously 'Noisy' tech. Been a while since I did hobby robotics, but brushed motors were the domestic equivalent of 'Spark Gap' transmitters. They needed close-coupled, over-rated, back-to-back Zeners, warily-rated...- Nik_2213
- Post #23
- Forum: Electrical Engineering
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Reality Check: Rogue Planet Flyby Scenarios and Survival Feasibility
FWIW, there is a wandering inter-stellar population of genuine 'Rogue Planets'. IIRC, some were probably tossed 'wild & wide' when their host star 'evolved' off main-sequence. Some probably came via the 'Brown Dwarf' route, perhaps not accreting to full size. Almost certainly, some were ejected...- Nik_2213
- Post #16
- Forum: Science Fiction and Fantasy Media
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Reality Check: Rogue Planet Flyby Scenarios and Survival Feasibility
Wiki, YMMV, has... https://en.wikipedia.org/wiki/List_of_nearest_stars This includes prior and pending passes... https://en.wikipedia.org/wiki/Scholz%27s_Star This mini-binary came close enough ~70ky ago to disturb Sol's Oort cloud. But, IIRC, such objects need another million years or so to...- Nik_2213
- Post #7
- Forum: Science Fiction and Fantasy Media
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Plausible Physics for a biblical Ark
Um, this *is* the tamper-trapped 'Covenant' Ark, with historical provenance, rather than the 'Noachian' absurdity ? The latter mega-hyped from Gilgamesh river-flood reportage ?? Two thoughts: If you dig into the electro-chemistry, you'll find it is as easy to use a primitive battery to...- Nik_2213
- Post #14
- Forum: Sci-Fi Writing and World Building
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Plausible Physics for a biblical Ark
If the 'Baghdad Battery' was used for electrolytic acceleration of acid-leaching, comparable to the Incas' acidic Andes streams, rather than a gold-plating system, then a 'Voltaic Pile' might follow. Given the 'Angelic Ark' was claimed to be a hefty whatsit, it could readily accommodate enough...- Nik_2213
- Post #2
- Forum: Sci-Fi Writing and World Building
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Molds in Front Loading Washing Machine
I suspect it correlates with majority of cycles now being cool 'eco-washes'.. IIRC, everything except 'fragile' used to run on a 'hot' wash. Such attrition seemed to keep the dreaded bio-film at bay. Now, 30ºC eco-wash is routine --And effective !!-- with 'hot' washes reserved for 'Heavy Soil'...- Nik_2213
- Post #12
- Forum: Biology and Medical
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Molds in Front Loading Washing Machine
I had an extended battle with black mould both in and behind our front-loader's detergent / softener tray. Unfortunately, a family member kept banging knee on drum's ajar door, would slam it shut.. And, without that minimal air circulation, mould set in..... There is usually a covert latch or...- Nik_2213
- Post #10
- Forum: Biology and Medical
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Do old CRT and O-scopes degrade to emit harmful X Rays?
Please DO NOT dispose of that lead-doped glass such that recycling *might* mix it with food-grade feedstock. Yes, yes, considerable dilution should occur, but the popularity of 'flat screens' means fragmented 'legacy' lead-fronted 'Bottles' may be over-looked...- Nik_2213
- Post #6
- Forum: STEM Educators and Teaching
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I am writing a SciFi story but I don't like Rayguns
Not necessarily. Don't forget some 'big' guns use 'bagged' charges. Technically, case-less... A magazine may include a small can of 'coolant' to better flush breech. Barrel heating is a bane of repeated firing, but a limited 'kick-charge' would mitigate that... Also see...- Nik_2213
- Post #48
- Forum: Science Fiction and Fantasy Media
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I am writing a SciFi story but I don't like Rayguns
I gave ' Expansionist Imperial' antagonists in a story-arc 'Hybrid Rocket Guns'. Down-side of 'trad' rocket guns is slow exit from barrel. The 'Gyrojet' lacked lethality at short range. And, when it 'got going', was sub-optimally accurate due aiming / spin issues. Reloading required external...- Nik_2213
- Post #45
- Forum: Science Fiction and Fantasy Media
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The Short Story Thread: Post Yours Here
Life World Most galactic species call the Terrans 'Death Worlders', for the myriad ways their home planet will kill you. A few, wiser, call that planet a 'Life World' {Spit_!!}, and shun Sol System as if about to go 'nova'. Consider how Terrans' mites, ants and roaches seem immune to most...- Nik_2213
- Post #23
- Forum: Sci-Fi Writing and World Building
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Using a copper pipe in an aluminum tank?
I'll not say 'DO NOT !!' but, IMHO, putting such electro-dissimilar metals into proximity is a very poor idea. IIRC, there are stiff-ish 'potable' grade polymer laminate pipe types which would side-step issues..- Nik_2213
- Post #4
- Forum: Materials and Chemical Engineering
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What is this metal insert for in a desk?
Note metal Cam lock dowels may even be double-ended, for joining panels end-on. A range of lengths available... Discovered such when needed to 'Frankenstein' two flat-pack kitchen units as '50' + '40' cm, when range did not include a '90' cm and '100' cm would be 'Just Too Long'... Yes...- Nik_2213
- Post #4
- Forum: Materials and Chemical Engineering
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Mono-isotopic silica melting points?
Sorry, my Google-Fu cannot find any' reference... Silicon has stable isotopes '28' ~92%, '29' ~5% and '30' ~3%. Oxygen has stable isotope '16' at >99 %, so effectively mono-isotopic. Do the three Si isotopes have significant effect on melting point etc of their silica SiO2 ?? For a...- Nik_2213
- Thread
- Replies: 1
- Forum: Materials and Chemical Engineering