How does adding texture to a surface reduce drag? |
- How does adding texture to a surface reduce drag?
- How would I give directions to earth?
- Questions about the stem cell therapy of the wilson disease?
- How is the James Webb telescope, especially its delicate foil shield, protected from space debris?
- Is immunity stored in dna?
- Is there an upper limit to the highest possible bypass ratio of a turbofan engine?
- What does p-value really mean?
- In stimulated emission, is the photon emitted in the same direction as the initial photon?
- Effectiveness of Malaria Vaccine against different plasmodiums?
- Why do people say that the expansion of the spacetime is accelerating if the Hubble sphere is expanding?
- Does common cold and flu both spread by the same mechanism?
| How does adding texture to a surface reduce drag? Posted: 18 Oct 2021 03:43 PM PDT I saw that Airbus is trying to mimic shark skin's denticles to decrease drag, but I don't understand how something rough creates less drag than something smooth. How does this work? Is it similar to why a golf ball has dimples? [link] [comments]  |
| How would I give directions to earth? Posted: 18 Oct 2021 12:30 PM PDT Hypothetical. I wake up on an alien space station. We can communicate fine, and I judge them to be good people, no threat to humanity. But I need to get home. I know I'm in the Milky Way. I don't know how long I've been asleep. They know most of the galaxy by documentation of it's visable properties at minimum, but given specifics they can narrow their search. What information could I provide them, if any, to point them back to Sol? Or are things too much in motion to use anything as a reference? Thanks, [link] [comments]  |
| Questions about the stem cell therapy of the wilson disease? Posted: 19 Oct 2021 05:25 AM PDT I have a number of questions about the Stem cell therapy for the wilson disease. I tried to look into this myself, but i cant find much information about this. Any relevant sources and links would be very helpful. 1.What stem cells are used and how are they obtained? 2.Are the stem cells themselves inserted into the patient? Or are the stem cells cultured in a lab to become a certain type of specialised cell which is then inserted into the patient.
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| How is the James Webb telescope, especially its delicate foil shield, protected from space debris? Posted: 18 Oct 2021 11:47 PM PDT |
| Posted: 19 Oct 2021 03:17 AM PDT Does our dna learn how to have an immune response to a virus and store that information? Why do we need boosters, do they forget that information over time? [link] [comments]  |
| Is there an upper limit to the highest possible bypass ratio of a turbofan engine? Posted: 19 Oct 2021 05:26 AM PDT I am not an engineer and only have an rudimentary understanding of the physics behind the jet engine, especially for commercial airliners. Admittedly, much of the physics behind why a high bypass ratio for commercial airliners is fuel efficiency was quite counter-intuitive for me, I.e slower compressor speed and more air directed to bypass duct means more thrust. Theoretically, how far high up can the bypass ratio be reached and what new technologies can enable greater fuel savings and greater range for jet engines? [link] [comments]  |
| What does p-value really mean? Posted: 18 Oct 2021 12:36 PM PDT |
| In stimulated emission, is the photon emitted in the same direction as the initial photon? Posted: 18 Oct 2021 08:22 AM PDT When an atom absorbs a photon, it will absorb its momentum as well and recoil in the direction which the photon was traveling. When an atom spontaneously emits a photon it will experience a recoil in the opposite of whatever direction the photon was randomly emitted in. What about stimulated emission? Will the newly stimulated photon be emitted in the same direction as the initial photon (thus giving the atom a recoil in the opposite direction of the initial photon direction), or will the stimulated photon go in a random direction (or is there a more complicated probability distribution over which direction the stimulated photon is emitted)? [link] [comments]  |
| Effectiveness of Malaria Vaccine against different plasmodiums? Posted: 18 Oct 2021 08:57 PM PDT Exactly what the title asks. I haven't been able to find a lot of info about the efficacy of the Mosquirix (RTS, S) vaccine against different plasmodium species that cause malaria. Any Immunologists or Biologists who can answer this? [link] [comments]  |
| Posted: 17 Oct 2021 05:59 PM PDT My understanding is this: The Hubble sphere is the distance from us at which spacetime (and the objects in it) are moving away from us at c. Assuming that the expansion of spacetime is constant, then that distance would also be constant. But, if the expansion of spacetime is accelerating, then the distance to space that is moving away at c would get closer to us over time, and thus the Hubble sphere would shrink. And if the Hubble sphere is instead expanding, that means that the expansion of spacetime is actually decelerating. But people say that the Hubble sphere is expanding AND that the expansion of spacetime is accelerating, which are completely contrary to each other. Is my understanding incorrect? Am I missing something? [link] [comments]  |
| Does common cold and flu both spread by the same mechanism? Posted: 17 Oct 2021 06:11 PM PDT |
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