All Activity

This stream auto-updates     

  1. Past hour
  2. StringJunky

    U.S. Democratic Primary

    That seems a bit weird, considering how long ago that was. Certainly, some kind of memorial effort would be good.
  3. Today
  4. franco malgarini

    Air compressed wind energy
  5. iNow

    U.S. Democratic Primary

    Warren is leading an issues first campaign. We’ll see how it works out. Today, for example, she called for an end to the electoral college. Also, affordable housing. Breaking up tech giants. Then today, financial reparations for the families of former slaves.
  6. Q-reeus

    Propellant less space engine

    From John Lowe's first post: "...but if somebody could at least explain what is wrong with my logic I would appreciate it..." Actually, you seem quite unappreciative. Why have you totally ignored my attempt to point out basic flaws in your reasoning? Obsessed? Totally sure you are right? Unwilling or unable to apply the formulae in article linked to? Not up to doing your own search for role of stress in relativistic physics? Or just ignorant maybe?
  7. Endy0816

    An ohmic contact

    Top is unfillled for monovalent. Easy route for electrons. You need gaps forming and then multiple electrons changing positions in the valent band for holes.
  8. Meredith, I have a question.... How would this person be alive and not be totally dehydrated...? Like don't you think it is slightly more likely that this person has some type of mental disorder or is faking it (or of course that news you have heard is just fake?)? Because I personally fail to see how this person is alive, if she can't ingest WATER. She will become totally dehydrated, and she most certainly did not live her entire life while getting water through her blood right? Also shouldn't she be getting into shock the moment the air is a bit humid? I presume that doesn't happen? -Dagl
  9. I' d request a case study before explaining anything.
  10. In the case of in real-time VR game simulation, you place two 3D virtual cameras for left and right eye. If person's head is at P 3D vector, left camera is at P-EYE, and right camera is at P+EYE, with EYE being vector with ~3 cm magnitude, direction of vector depends on rotation of the head of player. Majority (if not the all) of currently existing VR headsets can't track human eye movement to change angles at which 3D cameras are pointing at. So focusing is implemented by movement of mouse controlled aim cursor. Game know what 3D object is under mouse cursor, and know what is distance to that object (from analyze of Z-buffer for instance), and can set up 3D camera angles accordingly to have focus on it. Or alternatively it always focus on what is directly in the center of rendered image. It won't work with prerendered static data, like 3D movie, though. Astronomers are doing it using liquid highly reflective metal such as Mercury.
  11. Moreno

    An ohmic contact

    Principally, similar question can be related to p-n junction. But if in the case of p-n junction there is flow of holes into n-type region (forward bias), how there could be flow of holes into metal in the case of metal-semiconductor ohmic contact? Monovalent metals typically conduct no holes...
  12. Yesterday
  13. How do you explain this case where this girl went into anaphylactic shock from taking just a mouthful of water by accident?'s+deadly+allergy...-a061152595 She needed to be injected with adrenaline to prevent death.
  14. Perhaps for context, there are aquagenic ctuaneous disorders (urticaria, pruritus, acrokertoderma, depending on their manifestation). As they are so rare, they are quite understudied. However, claims of an "allergy" that do not fall into these categories are rather suspect. There are some studies suggesting that they could be the manifestation of systemic diseases, or at least associated with them.
  15. Many worldwide are pushing an anti-intellectual agenda, seemingly to make the average person mistrust educated people. Claiming the textbooks are wrong is one of the main themes to this propaganda, so I hope you aren't a part of this. Personally, I think it's part of a movement by the oil & gas industry to deny climate change by calling all our knowledge/expertise into question in order to delay phasing out fossil fuel use.
  16. I have no idea what "Montrel" is. And that link could be a work of fiction for all I know. As you are unable to provide a reputable source, I am sceptical of the whole story. Maybe you have made it up. Quite. Or she is faking it for attention.
  17. I never studied optics in physics, but can you guys tell me if a lense would go linear? It sounds like chr2019 is working on a video game. I have a vr headset and distances don't focus in distance to reading writing on the viewpoint. This is why a standard viewpoint using trig and an angle would work for a rifle simulator and eye chart but what do you do if you want to emulate a person's viewpoint? i realize you could always have a linear viewpoint calculated for different perspectives. But I am not skilled enough as a programmer to do this. It seems too memory and computational anyway. There are already Unity and other tools libraries. Isn't this a major problem in optics. My eye doctor said if I could invent glasses that focus near and far I'd be a millionaire.
  18. taeto

    Einstein in pre-Nazi Germany

    That is an interesting comment. I cannot come up with many examples of "opponents" of relativity from the first half of the 20'th century who were obviously anti-semitic. It did not really kick in as a popular item until late. I could volunteer numerous examples that I have encountered and/or engaged of current day anti-Einstein cranks who are very openly anti-semitic (as well as anti-Cantor cranks, for that matter). These days, it seems a vastly more popular thing. Admittedly, it is usually easier to identify a crank in our time, because it has to deny a hugely larger compound of observational evidence than was present 75 years ago. In previous times, they seemed somehow more timid and less attracted to public exposure. So that might skew the statistics.
  19. This right here is why I like SF, you sir have made my day with your post, this is why I’m coming back here except for the physics section ofcourse and for trolling the crackpots from time to time. Oh shut up Dim. I love you man. Please keep being who you are.
  20. Again, the only known cases of reactions to water are not allergic reactions, though the cause is little understood from what I see. These conditions are associated with skin contact, but not ingestion. Hypotheses ranges from the reaction of waters with sebum or sebaceous glands with subsequent stimulation of mast cells, pressure changes in hair follicles in presence of water and a few others. But the basic idea is that water reacts with something in the epidermis which then causes the reaction. Which is why sweat and tears elicit a response but saliva swallowing does not.
  21. Phi for All

    Are Humans Aliens of this Planet?

    We have a richer, denser, higher level of intelligence than most other animals. We don't have rows and rows of replaceable teeth. We don't have razor sharp claws. We can't flap our wings and fly. All animals use their talents to adapt to changing environments, and our intelligence coupled with some other skills (cooperation, communication, too use, for instance) allows us to be this "different". As vertebrates, our ancestry goes all the way back to tiny little fish that were the first creatures with skeletons on the insides. We've diversified much since then.
  22. Moreno

    An ohmic contact

    Isn't an ohmic contact a variety of a metal-semiconductor junction? In the case when the later doesn't have rectifying properties? My question was: why contact of a higher work function metal and a lower work function P-type semiconductor is an ohmic junction? When we apply potential and make electrons flow from metal to semiconductor in the case above doesn't semiconductor suppose to case resistance to such flow? And also, if electrons start to flow from metal to semiconductor, doesn't they suppose to recombine with holes and make semiconductor depleted for any kind of carriers further increasing the resistance? How P-type semiconductor can conduct free electrons, those which belong to conduction band of the metals?
  23. studiot

    Mass/energy equivalence question

    Not really forces, no, although they may be present and indirectly contributory. consider a (small) tank containing a hydrogen and oxygen mixture. This has potential energy you can release by igniting the hydrogen, but there are no forces between the particles whilst the tank sits there. Well there's translational energy (often called kinetic energy) vibrational energy rotational energy Heat energy (which is really a mixture of the above three) Then there's nuclear binding energy and some more esoteric types. Sort of but it get very complicated very quicky when you start talking about the tensors in general relativity that contribute to this.
  24. Saliva is 99.5% water.. Sea water is 94% water.
  25. Phi for All

    How do you feel about the progress of your life?

    When you lumped yourself in with the OP by claiming Royston's narrative might be what vexed you at the start. I suppose one could read that you were claiming Royston had talent you lack, but I didn't. Does not being as talented change the necessity of trying to better your situation? Don't you still have to be the person in charge of driving your own progress, even if you get help from others?
  26. studiot

    An ohmic contact

    Just use the conventional terminology, like everybody else. Then there is no confusion. A Schottky junction is the same as a metal-semiconductor junction. The emphasis is on the word junction the other words distinguish it from a semiconductor junction device. The other alternative is called an ohmic contact and does not include the word junction. Now that we have got that cleared up how about being more specific with your actual question that a link to an 11 page pdf? (Glancing through the document suggests it is worth reading, )
  1. Load more activity