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Cake day: July 5th, 2024

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  • skibidi@lemmy.worldtoScience Memes@mander.xyzPhD ain't no MD
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    3 months ago

    Completely correct. There is also a (much rather in the US) ScD degree - Doctor of science.

    In the US, it is often identical to a PhD. If your institution offers it, you just check a box at the end of your program on whether you want a PhD or ScD. In Europe, an ScD is a higher degree than a PhD and requires some extra work to obtain.



  • I’d be very careful relying on that site… just flipped through some of the build and it was very strange.

    E.g. they were recommending a $500 or $900 CASE at the highest tiers - not even good cases, you can get something less than half the price with better performance. They recommended a single pcie 4.0 SSD and a SPINNING HARD DRIVE for a motherboard with pcie 5.0 m2 slots. Recommending CPU coolers that are far, far in excess of requirements (a 3x140mm radiator for a 100W chip? Nonsense). Memory recommendations for AMD builds are also sus - DDR5 6000 CL30 is what those cups do best with, they were recommending DDR5600 CL32 kits for no reason.

    Just strange… makes me question the rest of their recommendations.



  • The momentum is the same, the impulse (and therefore forces) are very different. The bullet is propelled down the barrel gradually - the force is spread through the entire time it takes the bullet to travel the length of the barrel, the reaction forces are applied to the stock gradually, and spread over the area of contact between the shooter and the gun.

    A bullet stopped by a vest/plate has a much larger impulse. The bullet needs to be stopped essentially immediately, rather than gradually slowed down over a length equivalent to a rifle barrel, otherwise it kills you. The force is also more concentrated, occuring over the cross-sectional area of the bullet, rather than over the entire contact surface with the rifle.


  • It depends on the type of fusion.

    The easiest fusion reaction is deuterium/tritium - two isotopes of hydrogen. The vast majority of the energy of that reaction is released as neutrons, which are very difficult to contain and will irradiate the reactor’s containment vessel. The walls of the reactor will degrade, and will eventually need to be replaced and the originals treated as radioactive waste.

    Lithium/deuterium fusion releases most of its energy in the form of alpha particles - making it much more practical to harness the energy for electrical generation - and releases something like 80% fewer high energy neutrons – much less radioactive waste. As a trade-off, the conditions required to sustain the reaction are even more extreme and difficult to maintain.

    There are many many possible fusion reactions and multiple containment methods - some produce significant radioactive waste and some do not. In terms of energy output, the energy released per reaction event is much higher than in fission, but it is much harder to concentrate reaction events, so overall energy output is much lower until some significant advancement is made on the engineering challenges that have plagued fusion for 70+ years.


  • Just jumping in to say that red soils are not very fertile. They are nutrient-poor in the necessary macro-nutrients (nitrogen, potassium, and phosphorus) and have a very poor ability to retain water. They are very rocky - little organic matter content - which limits both water retention and cationic exchange capacity (affecting N+ and K+ bioavailability), and tend to be acidic.

    Cultivation is possible, but it requires large amounts of fertilizers and soil conditioning agents (liming to raise pH and add calcium, addition of organic matter). In effect, recreating an artificial soil that is closer in nutrient availability to the black soils present in the world’s most fertile regions (which today are also heavily fertilized).