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Carl Fredrik Ahl

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Posts posted by Carl Fredrik Ahl

  1. 48 minutes ago, koti said:

    Although common belief is that vaccines are injected directly into the bloodstream, they are actually administered into muscle or the layer of skin below the dermis where immune cells reside and circulate as occurs following natural infection”

    https://www.chop.edu/centers-programs/vaccine-education-center/vaccine-safety/immune-system-and-health

    „Most vaccines should be given via the intramuscular route into the deltoid or the anterolateral aspect of the thigh. This optimises the immunogenicity of the vaccine and minimises adverse reactions at the injection site. Recent studies have highlighted the importance of administering vaccines correctly.1–3 Clinical practice needs to reflect considerations about the right length and gauge of needles used to ensure that those vaccinated get the immunological benefit of the vaccines without local side effects”

    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1118997/

     

     

    I have read that, but thanks. Now I wonder what would happen if you were to inject it directly to the blood stream.

  2. 16 hours ago, Strange said:

    When you are cold, the body has to generate more heat, not less. So if anything you should feel more active so that you will warm yourself up.

    But generating more heat means more energy being used.

    16 hours ago, Prometheus said:

    Dehydration is probably a significant factor.

    Yeah, but even if you drink much water, you still can feel tired when it's hot right?

  3. 4 hours ago, Strange said:

    Do you have any evidence for this?

    No, I just guessed.

     

    5 hours ago, Strange said:

    Or maybe the difficulty of dissipating heat means that the body's natural response is to slow down in oder to control body temperature - it makes us feel tired to stop us generating more heat.

    Just found this, which confirms my latter guess: https://www.livescience.com/60116-why-heat-makes-you-feel-tired.html

    Okay, but why doesn't you feel tired when your cold? Then the body also has to regulate the body temperature.

  4. Hi,

    I know that laser guided bombs works by projecting a laser to an object and the bomb will have a photosensor that tries to keep the reflected laser in the center of the sensor, right? What I wonder is how does it know how to move in order to keep the laser in the center of the photosensor? Is this the only thing it requires to hit the target? Trying to move little all the time to keep the reflected laser in the center of the photosensor? 

  5. Hi,

    I wonder how monochrome, sunlight-visible, transflective memory-in-pixel (MIP) displays works. Like the one on my Garmin Instinct. Does it work like e-ink displays? The more light getting on the watch, the easier you see the display. When it's dark you can't see it at all. Image below.IMG_20190318_120141.thumb.jpg.2de87f7847a2bd8483a2ed86dac7949c.jpg  

  6. 3 hours ago, StringJunky said:

    I think the voltage regulator in a regulated device swaps voltage for current as the voltage drops to maintain the watts.  When it drops to about 3.2v the device will shut down to protect the battery. The load on the battery increases to maintain the power. 

    My device's output voltage is from 0.5 to 9 volts and the battery is 1600mAh. If it uses 9 volt when vaping 50 watts, how can it then vape at 50 watts when the voltage drops down to like 5 volts for example? Thx for the answer, but can you explain in more detail plz?

  7. Hi,

    I wonder how devices like vapes for example can have the same wattage until the battery dies. Shouldn't wattage drop down when the battery level drops, because then the voltage will be lower?

  8. 1 hour ago, DrP said:

    What happens when you dry a potato or a cucumber?  (it shrivels).

    What happens when you let the air out of a balloon or a tyre?

    Yeah ok thx for explaining. No I wonder why does it pull away from the skull? Is it because the movement when it shrivels? and what happens when it pull away for the skull except feeling pain. Is there any benefit for the brain to do so?

  9. Hi,

    Let's say that the watch in this example is AMOLED so that the battery usage depend on the color of the display:

    When smart watches go to ambient mode the background of the screen turn dark (in most cases, some just reduce brightness of the screen) and the rest of the watch face turns white. I wonder why the rest of the watch face turn white, which is the most battery consuming color to display, rather than red for example, which only require the red led to light up? I know that it's easier to see white, but red would save more battery.

  10. Hi,

    I know how LCDs and OLEDs works. LCDs uses a backlight and liquid crystals to control how much light is passed through the color filters. In OLEDs all pixels lights up by them selfe. Now, I wonder a few things:

    1. Why can't LCDs be completely dark? I know that the backlight is on all the time, but the polarizers can align so that no light can come through?

    2. Why does OLEDs have better contrast? Is it because it can get completely dark? LCDs can still get brighter. 

    3.  Why does OLEDs have better viewing angle than LCDs?

  11. 18 hours ago, Strange said:

    (Photon, not proton.)

    Spelling mistake or auto corect, sorry. I ment photons.

     

    18 hours ago, Strange said:

    Apply a voltage and the LCD twists the polarisation of the light (because the photons interact with the asymmetric charges in the molecules) so it no longer passes through the second filter.

    Yeah I know this but I wonder why it twists. What makes it twist explained in atomic level? Thx for the answer btw. I totally forgot that the electric field attract or repell the charges in atoms 

  12. Hi,

    I know that liquid crystals align with the electric field and therefore are able to either let the backlight through or not depending on if the there are electricity or not. What I wonder is why do the liquid crystals align with the electric field and why does the protons of the backlight wants to go in the direction of the liquid crystals?

    Source: 

    

     

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