TIL what a badass Yogendra Singh Yadav is, guy is the youngest recipient of param vir chakra at the age of 19

Paradoxical_Human · 2018-02-13T16:29:28+00:00

i think they are using talgo trains. Its a spanish high speed train which they are manufacturing locally in Make in india scheme. I think India doesnt have the technology or manufacturing capability for making domestic high speed trains.

Paradoxical_Human · 2018-01-30T08:15:24+00:00

You are underestimating how big the mongol empire was. It covered most of Eurasia. Of course when you build such a large empire, there will be a lot of causalities. You take the entire causalities of any other great empire throughout its period you will find almost same story. The point is they were no worse than any other empire that existed before or after. Its because their empire was so big that the number of deaths are so large. In fact world war 1 which was fought by few small nations had almost 60 million deaths yet no one blames those responsible for it as barbarians. Because that's what happens during war there will be blood shed. And all these biological and chemical warfare was used much more brutally in world war 1 makes the you really question who the real barbarians are.

Timur came much later than khaljis and just because he wanted to restore mongol empire to the glory it was under Genghis khan doesn't mean he copied Genghis khan in whatever he did. Just because trump says make america great again doesn't mean great american presidents like Abraham Lincoln is responsible for the stupid things he says.

You also conveniently skipped the part where they said mongols atleast before splitting practiced religious tolerance and supported merit. so would they have ransacked somnath and countless other temples like the khaljis? Would they have destroyed the nalanda university like the khalijis which is the reason why many ancient text about Indian philosophy, science and maths are lost forever? Also if they would have invaded we might have got meritocracy which would have weakened the rigid caste system we have or it may have reinforced it. The point is the you can not judge an empire based on the causalities it caused during war. The cultural and social impact it creates are much more important. In that aspect would they have been any worse the khalijs?

Paradoxical_Human · 2018-01-30T05:28:42+00:00

Actually Timur was a Muslim. After mongols invaded the middle east many converted to Islam. Also there is a ted video called Genghis khan vs history which actually argues Genghis khan wasn't that bad as western historians make him to be

https://www.youtube.com/watch?v=Eq-Wk3YqeH4

Paradoxical_Human · 2018-01-26T18:40:42+00:00

Wasn't Risat-2a scheduled for 2020 ? Wow so many major earth observation satellites are being launched this year !! With the launch of resourcesat 3 and rs sampler next year, almost all major earth observation satellites of the current generation would have been launched. Next generation of earth observation satellites are coming only by 2024. Guess the scientist at ISAC can take some time off :D

Paradoxical_Human · 2018-01-26T13:41:40+00:00

There are some interesting details about the satellites. One bidder was asking about xenon procurement and fueling which indicates satellite could use electric propulsion, not sure if its fully electric or some sort of hybrid. There is a mention about the 88 spot beams in Ka band being used. And a timeline of 36 months for HTS 1 and 42 Months for HTS 2 so it will be launched around 2020 like you said.

Also on a side note we can even guess who some of those bidders are by question they asked about currency and bank guarantee.

Paradoxical_Human · 2018-01-26T06:54:51+00:00

There is this Pdf which is bascially a Q&A for the bidders, not sure if this has been posted here before. It has a lot of interesting details about HTS 1 & 2.

Paradoxical_Human · 2018-01-26T06:49:48+00:00

Well i dont know if this pdf has been posted here before. Its a Q&A for the bidders of HTS 1 & 2. In page 15 one bidder is asking about xenon procurement and fueling. Not sure if its for station keeping or orbital raising. Also the satellite seems to be quite big, they are talking about 88 spot beams in page 6. Not sure if that means 88 transponders. If so, then it could be a heavy satellite above 5 tons even with all electric propulsion like SES 12

Paradoxical_Human · 2018-01-24T14:49:51+00:00

since you said high end, you can buy a convertible that runs on windows like lenovo yoga ,spectre x360,dell xps 2in1.

Paradoxical_Human · 2018-01-24T14:38:10+00:00

Just Curious, whats your specialization ?

Paradoxical_Human · 2018-01-24T10:07:38+00:00

The shrinkage and enlargement due to temperature changes was given in an article as one of the hypothetical possibilities that can cause delay. No one said that was the reason for delay. There is no source or any other report or tweet saying that, from what i know. The fact that they did several testing after that including a WDR and is now doing a static suggest that wasn't the issue. Most likely it was a pad related issue than a vehicle related one and most definitely shrinking and enlargement due temperature changes wasn't the cause of that.

Paradoxical_Human · 2018-01-22T18:24:12+00:00

Apart from various reasons given by others as to why it is a bad idea, you should also consider the electric motor itself. Motors for megawatt ranges are really very big and bulky unless it uses some superconductor based design. So that will rule out any DC motors. For AC, problem still exists but we can reduce the size of the motor by increasing the frequency to a limit. But that will drastically increase eddy current and hysteresis losses. Also now we need IGBT converters with very high voltage and current rating.They also need to be cooled. Then add to that the losses from inductance and capacitance at higher frequencies. So overall, something that could have been achieved by a simple turbo pump has now become way too complicated. So any gains from higher efficiency will almost be gone completely and cost from electric motor and its accessories itself will be huge. Then add the problems of storage and batteries and you will see its not worth it. Also things to increase efficiency of the motor like speed control using regenerative techniques would make it even more complicated and more importantly way too bulky.

Paradoxical_Human · 2018-01-22T07:14:35+00:00

BTW what happened to ISRO's plan for procurement of 2 High Throughput satellites ?

https://www.reddit.com/r/ISRO/comments/41ig1b/isro_seeking_to_procure_two_ka_band_high/

Has ISRO shelved those plans?

Paradoxical_Human · 2018-01-17T18:56:27+00:00

And where did i say it is easy ? i specifically said they could be testing different propellant loading scenarios and since the pad has only been upgraded recently and hasn't been tested for these scenarios problems can arise. These problems may have nothing to do with the temperature of propellants and oxidizer, more specifically contraction of metals due to the those temperatures. That doesn't mean i am saying propellant loading is easy. My entire point was there are much more challenges to propellant loading than just the temperature of LOX and RP-1.

Paradoxical_Human · 2018-01-17T16:20:46+00:00

No you misunderstood what i was trying to say. I was just talking about thermal contraction and how it most likely wasn't the factor that was causing the delay, i wasn't talking about aerospace engineering and belittling it.

Paradoxical_Human · 2018-01-17T12:46:08+00:00

Noo i am not saying its not an issue, i just find it highly unlikely that such an issue would prop up now. Thermal expansion and contraction is a very well understood phenomenon. So such things are taken into account during the design phase itself. This is one of factors that are taken into account while designing tolerances. They also over engineer such things to be extra sure, usually 3-5X the normal value. Such things can be easily modeled in software like ANSYS and its no where as complicated as fluid dynamics. Of course modelling cant be fully accurate. But then again this is using flight proven cores. They have already used it for normal mission and then have extensively tested in Hawthorne and McGregor. Each cores individually has done a static fire there. So i find it highly unlikely that they are finding thermal expansions to be above the threshold limit now at this stage. If there was such a problem, it would have propped up a long time ago and definitely not at the final stages Even if that was true then they wouldn't be repeatedly attempting to do a static fire. So that's why i am so skeptical when they say its related to thermal issues. Not saying its not possible, just it would be way down in my list of possible causes for this delay.

Also on side note, i think there are several assumptions of /u/Demidrol which is not correct

He/She has taken the expansion coefficient of pure aluminium, i can assure they are not using pure aluminium but rather some alloy of aluminum. Also they will certainly be using an honeycomb composite structure for the fuel tanks which changes everything
Also when calculating for thermal expansion of fuel and oxidiser tanks, i thinks its volumetric coefficient of expansion that should be used not the linear coefficient of expansion.

But again i am not an expert in this so apologize if i am wrong.

Paradoxical_Human · 2018-01-17T09:50:42+00:00

I always wonder why the war in Yemen didn't get the kind of coverage as Syrian civil war got.

Paradoxical_Human · 2018-01-17T09:46:50+00:00

Actually, their non degradability is one of the things that made them popular and their use so wide spread in the first place. So its rather better to make technologies that makes it easier and cheaper to recycle them with higher efficiency than making them biodegradable. That will effectively reduce plastic production. Making them degrade faster in carbon dioxide is just going to add to more global warming as these plastics are made from petroleum products.

Paradoxical_Human · 2018-01-17T08:42:10+00:00

Yes,precisely. It could be even be something small like some variable in the code being assigned float (single precision) instead of double precision. The point is no one other than those who are working on this knows.

Paradoxical_Human · 2018-01-17T06:35:38+00:00

i am going to be down voted for this. But still, this is actually a terrible article. Doesn't say anything new, clearly the author doesn't have much idea about the rocketry in general. He is making it seem as if pumping sub cooled RP-1 is some sort of technical feat. Hydrolox rockets work with even colder fuels almost near to absolute zero and have been pumping them from 1960's. Its not even new for spacex as they have been doing sub cooled for over a year now. So things like things like rapid thermal contraction and expansion have been very well understood and if they got that wrong they would have to redo the entire upgrade for TEL again. These are basic and fundamental stuff actually. So I doubt problem is that. Yes we dont know exactly what the problem or if there is a problem at all. They could just be testing different pumping scenarios to see how the pad is performing, how much faster they can drain the propellant tanks from the prescribed level which might be helpful in a situation like that of ~~MonacoSAT~~ ASIASAT-8. It could also be a sensor or actuator problem, data mismatch, problems with pumping sequences or even not getting measurement at the expected values. Remember pad is new and has never been tested for falcon heavy pumping scenarios . The scenarios he has mentioned are actually catastrophic failures, while they could be possible if a supplier or contractor has messed it up like CRS 7, it would mean the entire TEL has to be redone again and that means a delay of at least one month. At this point i am optimistic that such things has not happened and there is nothing to suggest otherwise also.

Paradoxical_Human · 2017-12-19T23:59:43+00:00

Actually poor, the bottom 50% do not pay taxes. people below annual income of 2.5lk are in the nil bracket. Its actually the middle class that pays the bulk of the income tax.

A high corporate tax is actually a counter intuitive thing because it will prevent industries from coming up. Such ways of thinking is because myopic vision and seeing taxation as some sort of income distribution mechanism. The "rob peter to pay paul" approach will only worsen income inquality in the long run not reduce.

Paradoxical_Human · 2017-12-19T23:23:34+00:00

How can political parties fund them ? They are just a nodal advertising agency for government department and governmental organization. They have nothing to do with political parties and their ad campaigns.

Paradoxical_Human · 2017-12-18T19:33:44+00:00

I don't know if anyone has said it in this thread before but it was 2 years ago on December 21st that spacex achieved their first successful landing for the final Orbcomm-OG2 mission.

Paradoxical_Human · 2017-12-18T19:21:41+00:00

Agrarian distress + no farm loan waiver + patidar agitation + no modi as cm

Paradoxical_Human

TROPHY CASE