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A board for scientific/technological discussion and the distribution of knowledge!


Скока надо тока чтобы панувати на Марсе Anonymous 06/26/2023 (Mon) 05:40 [Preview] No. 17 [Reply] [X] [Last 50 Posts]
Соберу в одном месте прикидки расчетов затрат электроэнергии

РАСХОД ЭЛЕКТРОЭНЕРГИИ НА ЭЛЕКТРОЛИЗ ВОДЫ

1 моль молекулярного водорода весит - 2 грамма
1 моль метана весит - 16 грамм
1 моль ЛЮБОГО газа при нормальных условиях занимает объем 22,4 литра.

Реакция
CO2+4H2->CH4+2H2O

На получение 1 моль метана израсходуется 4 моль молекулярного водорода.
На заправку ракеты надо 240 тонн метана или 15 миллионов моль метана (240000000/16) для получения которых надо 60 миллионов моль молекулярного водорода (1 344 000 м3 водорода - 60000000*0.0224).
Для получения 1 м3 молекулярного водорода из воды путем электролиза надо 4 кВт-ч.
Для получения 1 344 000 м3 молекулярного водорода из воды путем электролиза надо 5,376 ГВт-ч.

РАСХОД ЭЛЕКТРОЭНЕРГИИ НА СЖИЖЕНИЯ КИСЛОРОДА

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Anonymous 06/26/2023 (Mon) 05:46 [Preview] No.18 [X] del
Расчет по картофану

Растения должны быть изолированы от атмосферы и от потока протонов и ядер гелия солнечного ветра. Иначе им пиздец придет. Так что растить можно только в закрытых парниках под защитой слоя грунта и искусственном освещении.

Солнечная постоянная на орбите Марса 0,58 КВт/м2. На поверхности поток солнечного ниже, часть его поглощается и рассеивается в атмосфере. КПД солнечных панелей MER обеспечивал им 0,1 КВт/м2 днем.

Для вегетации нужен свет длиной волны 450-650 нм. Светодиодная лента с красными и синими светодиодами вполне покрывает этот диапазон.
Требуемая для картофеля освещенность 10 000 лк
Средняя урожайность картофана 100 ц/га (консервативно).
Следовательно для 1 т картофана нужна площадь 0,1 га или 1000 м2. Т.е. нужен световой поток 10 000 x 1000 = 10 000 000 люмен
Световая эффективность у светодиодов в среднем 100 Лм/Вт
10 000 000 / 100 = 100 000 Вт.

100 кВт электроэнергии для освещения которые обеспечат 100x0,1 = 1000 м2 солнечных панелей.

С обогревом сложнее, потеря тепла будет идти не только через теплопроводность грунта но и через излучение, все зависит от того как и чем будем теплоизолировать пол, потолок и стены помещения и кпд светодиодов.

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What's the science or algorythm to those 6 digit likes/sales social media post, content, illustrations?

Like waht are the criteria that makes them so?
maybe a line of algorythm so i can tell what i need to do to max up my post reach and such


Nordidyou Anonymous 06/19/2023 (Mon) 10:16 [Preview] No.15 [X] del
Bump


Anonymous 06/20/2023 (Tue) 09:43 [Preview] No.16 [X] del
Bump



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Betelgeuse Anonymous 06/16/2023 (Fri) 22:54 [Preview] No. 3 [Reply] [X] [Last 50 Posts]
Betelgeuse is a well known bright red supergiant that shows semi-regular variations with four approximate periods of 2200, 420, 230, and 185 days. While the longest period was customarily regarded as LSP (long secondary period) of unknown origin, we identify the ~2200-d period as the radial fundamental mode, and the three shorter periods as the radial first, second, and third overtones. From a nonadiabatic pulsation analysis including the pulsation/convection coupling, we have found that these radial pulsation modes are all excited in the envelope of a model in a late stage of the core-carbon burning. Models with similar pulsation property have masses around 11M_\odot (19M_\odot at ZAMS) with luminosities (log L/L_\odot =5.27~5.28) and effective temperatures (log T_{eff}\approx 3.53) that are consistent with the range of the observational determinations. We also find that a synthetic light curve obtained by adding the fundamental and the first-overtone mode qualitatively agrees with the light curve of Betelgeuse up to the Great Dimming. We conclude that Betelgeuse is in the late stage of core carbon burning, and a good candidate for the next Galactic supernova.


We have found carbon-burning models that excite the radial funda-mental mode, as well as the first, second, and third overtones. Theperiods excited pulsation modes agree with periods of 2190, 417,230, and 185 d that had been detected in Betelgeuse. On the HR dia-gram, these models are located within the allowed range of effectivetemperature and luminosity of Betelgeuse. Beginning with a massof 19 ⊙ at ZAMS (with a rotation velocity of 0.2 or 0.4 crit), themodels lose significant mass mainly in the core-He burning stage to have a mass of 11 ∼ 12 ⊙ in the core carbon-burning stage. A largeradius of about 1300 ⊙ (needed for the long-period fundamentalmode) is supported by interferometric measurements of the angulardiameter combined with the distance.

We conclude that Betelgeuseshould currently be in a late phase (or near the end) of the core car-bon burning. After carbon is exhausted in the core, a core-collapseleading to a supernova explosion is expected in a few tens years.

https://arxiv.org/pdf/2306.00287.pdf


Anonymous 06/18/2023 (Sun) 02:18 [Preview] No.9 [X] del
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Betelgeuse, the bright, yellow star at the top of the picture, dimmed considerably in 2020 (as seen in second image) and has since brightened by 50%. H.Raab/Flickr, CC BY-ND



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Gravitational Pair Production and Black Hole Evaporation Anonymous 06/18/2023 (Sun) 00:40 [Preview] No. 8 [Reply] [X] [Last 50 Posts]
We present a new avenue to black hole evaporation using a heat-kernel approach analogous as for the Schwinger effect.

Applying this method to an uncharged massless scalar field in a Schwarzschild spacetime, we show that spacetime curvature takes a similar role as the electric field strength in the Schwinger effect. We interpret our results as local pair production in a gravitational field and derive a radial production profile. The resulting emission peaks near the unstable photon orbit. Comparing the particle number and energy flux to the Hawking case, we find both effects to be of similar order. However, our pair production mechanism itself does not explicitly make use of the presence of a black hole event horizon.

https://phys.org/news/2023-06-black-hole-evaporation-theoretical-stephen.html

https://arxiv.org/pdf/2305.18521.pdf



1 TzwSVsOw 06/17/2023 (Sat) 03:42 [Preview] No. 7 [Reply] [X] [Last 50 Posts]
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1 TzwSVsOw 06/17/2023 (Sat) 03:41 [Preview] No. 6 [Reply] [X] [Last 50 Posts]
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1 Anonymous 06/17/2023 (Sat) 03:17 [Preview] No. 5 [Reply] [X] [Last 50 Posts]
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1 Anonymous 06/17/2023 (Sat) 03:17 [Preview] No. 4 [Reply] [X] [Last 50 Posts]
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Anonymous 09/09/2020 (Wed) 14:11:24 [Preview] No. 1 [Reply] [X] [Last 50 Posts]
thread for discussion of BTEC and A level sciences

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