Thread: Epic overuse/misuse of words

Originally Posted by holli4pirating

"Negative pressure" bothers me.

Probably a different context... Thanks to negative pressure you're able to breathe.

110% (as in he gave 110%), not possible.

Qualifiers on anything that is by its nature absolute (eg. kind of pregnant).

MRI (magnetic resonance imaging) the correct term is NMR (nuclear magnetic resonance); magnetics (what ever they may be) do not resonate.

Originally Posted by holli4pirating

Perhaps you should be axing yourself :-)

or "Axe" 1OldGI what you should be "axing" yourself

Originally Posted by MasterRolf

MRI (magnetic resonance imaging) the correct term is NMR (nuclear magnetic resonance); magnetics (what ever they may be) do not resonate.

I kind of understand what you're saying, 110%

Originally Posted by MasterRolf

110% (as in he gave 110%), not possible.

Qualifiers on anything that is by its nature absolute (eg. kind of pregnant).

MRI (magnetic resonance imaging) the correct term is NMR (nuclear magnetic resonance); magnetics (what ever they may be) do not resonate.

Well yes and no...technically, you are right. The resonance stems from the nuclei radiating back the energy absorbed from the EM pulse. This energy, which is radiated back out, is at a specific resonance frequency (which depends on strength of magnetic field, etc...). By definition:

NMR = Nuclear Magnetic Resonance is used primarily in scientific research (structural biology etc...). It is the resonance that occurs when a nucleus (usually hydrogen, but any nucleus that has non-zero spin will work) is placed in a magnetic field and is 'swept' by a radio frequency that causes the nuclei to 'flip'. This causes the radio frequency to be absorbed, which is what is measured.

MRI = Magnetic Resonance Imaging is use more in clinical settings (medicine). it is a more complex application of NMR in which the geometric source of the resonances are detected and deconvoluted by Fourier transform analysis.

Essentially, they do the same thing.

The main factor, imo has to do with nomenclature...Imagine if a doctor requested a patient to have a Nuclear Magnetic Resonance Imaging (rather than MRI) done, 95% of the patients would freak out. I believe that the term (for clinical practice) was changed to ease patient concerns.

But, that's just my 2 cents

Originally Posted by BladeRunner001

Imagine if a doctor requested a patient to have a Nuclear Magnetic Resonance Imaging (rather than MRI) done, 95% of the patients would freak out. I believe that the term (for clinical practice) was changed to ease patient concerns.

We have a nuclear medicine department at the facility where I work. Patients are injected with a radioactive isotope for imaging studies. I've never seen anyone freak out when it's explained to them that they are going to have radioactive material injected into their body.
Some ask questions, but I have yet to see anyone refuse a study.

Originally Posted by HNSB

We have a nuclear medicine department at the facility where I work. Patients are injected with a radioactive isotope for imaging studies. I've never seen anyone freak out when it's explained to them that they are going to have radioactive material injected into their body.
Some ask questions, but I have yet to see anyone refuse a study.

You are right HNSB...these days, they do all sorts of nuclear/isotope labeling and dye imaging these days as these become common place in medicine. But, I was speaking historically...I recall a panel that was set up shortly after the publication of an article outlining the successful use of NMR in humans (I think late 70s or so). The panel was to discuss the merits of whether they should change the name to something other than NMR, exactly because of the uncertainties associated in using the word "nuclear". If I recall, it was decided that by using the term as is, will result in the widespread "fear" amongst patients, and patient groups...so the term was MRI...less innocuous and "invasive"-sounding. Not to mention, they are slightly different in the way they image.

That makes sense.

Originally Posted by HNSB

Probably a different context... Thanks to negative pressure you're able to breathe.

I would say that's not negative pressure, but rather a difference in pressures.

Pressure, as I understand it, is the amount of force per unit area. Area cannot be negative, and technically speaking, neither can a force. Negative for a force is really shorthand, when it is in a direction that has been stipulated as "the negative" direction within the scope of a given problem. Unless you are discussing something for which the general population (or at least the general population that deals with whatever you are talking about) has agreed on a negative direction, the use of the term "negative pressure" is, at best, contextual and slightly ambiguous. For example, does gravity act in the positive or negative direction? I would say there is no generally accepted convention - depending on what problem you are trying to solve, one or the other may be easier to work with.

You are right though, I was referring to the use of "negative pressure" with regards to honing. When I think of pressure, I think of the amount of pressure between the parts of the razor that touch the hone and the hone. Here, that pressure cannot be negative. I think of pressure this way because this is the "pressure" one would seek to control. I also think this is the conventional use of "pressure." For example, we often talk about "the least amount of pressure possible" when finishing on any given hone.

A possible alternate "pressure" would be related to the force applied to the razor by your hand. But that's not really "pressure" at all, because it has no clearly defined surface. If one was to imagine the "surface area" was "the sum of all surface areas between your hand an the razor," then there would be some problems. A person holding a razor in just their fingertips and applying a downward force of... let's make something up... 1 Newton downwards might be applying MORE pressure than a person holding the tang and scales in their fist and applying... on I don't know... 50 Newtons downwards. But I think we would all agree that the person applying 1 Newton downwards is the one applying less "pressure" - so this definition seems to fail.

Even if this definition did work, it's still an upward force, not a negative pressure. You're not repelling your hand from the razor (that's the only possible think I can think of for negative pressure, but even that is inaccurate), but rather applying a net upwards force to the razor which is less than the downward force due to gravity.

I don't really have a problem with the phrase "negative pressure" being used, as I believe I understand what is being discussed (which is what matters) and I'm fine with "negative pressure" being adopted and adapted, but my inner physicist still notices it every time and lets me know.

The forces don't know or care where you have chosen to place the reference frame's zero point