These are usually abstracted as point-like particles, even though they have volumes, shapes, structures, etc. The term macroscopic particle, usually refers to particles much larger than atoms and molecules. The term "particle" is usually applied differently to three classes of sizes. However, the noun particulate is most frequently used to refer to pollutants in the Earth's atmosphere, which are a suspension of unconnected particles, rather than a connected particle aggregation. Anything that is composed of particles may be referred to as being particulate. The term particle is rather general in meaning, and is refined as needed by various scientific fields. Particles can also be used to create scientific models of even larger objects depending on their density, such as humans moving in a crowd or celestial bodies in motion. They vary greatly in size or quantity, from subatomic particles like the electron, to microscopic particles like atoms and molecules, to macroscopic particles like powders and other granular materials. In the physical sciences, a particle (or corpuscule in older texts) is a small localized object which can be described by several physical or chemical properties, such as volume, density, or mass. You'll then see that this is a specimen and not a sample and simply cannot be representative of the whole.Arc welders need to protect themselves from welding sparks, which are heated metal particles that fly off the welding surface. With any assumption, calculate the total mass of the particle(s) shown. The image is a tiny representation of the whole. Yep, a normal thing we have to do manually In the number-based evaluation then a 1 nm particle has the same weighting (statistical validity) as a 10 nm particle even though it contains just 1/1000 of the mass or volume or number of atoms/molecules This is vital in understanding what other techniques may give on the same system. Conversion to other forms - length, surface, volume, and intensity distributions).What are overlapping (one particle behind another), touching, aggregated, and agglomerated particles? Should we deconvolute/disperse them in software?.So the bottom end of any technique determines this (hence the flawed EU number-based definition of nanomaterial)
Yes, what is the 'truth' here? The harder we look then the more we see.
OPTIMAGE PARTICLES SOFTWARE
3 decimals in nano (pico) is ludicrous (and software developers persist in this nonsense) when we realize that the approximate diameter of a hydrogen atom is 0.074 nm or 74 pm
Like most software, far too many decimal places are generated (yes, generated they're not real.). Spherical (3-D) is an assumption - disc (2-D) is not. Yes, your comment 'The particles seem spherical though, so I guess this would be a reasonable approximation?' is worthy of much further dialog - what I query is the word 'spherical' - the particles do not seem spherical at all as we have no indication of the z-axis. We can just as easily state the nonsensical 'Imaging only applies to discs' when we know that visualization is essential/mandatory. We used to get nonsense such as in light scattering 'Mie theory only applies to spheres and your particles are not spherical'. So, we need to be aware that shape is a 3-D issue and that equivalents (circular/spherical etc) are used in imaging just as in any other size determination of irregular particles. Here ratios of 1-D parameters (such as Feret or aspect ratio) can be determined as well as appropriate equivalents. Here I'd look to the essential (IMHO) chemisorption SSA which should be able to 'highlight' the smaller fraction This is why complementary techniques are of so much benefit. Some of this may be due to depth of field but we need to be aware of how this happens. Even though the excellent Image J has the ability to deal with a varying background there is still a great deal of subjectivity and manual/visual interpretation
OPTIMAGE PARTICLES PLUS
But you are from Slovenija (and Ljubljana - a wonderful and beautiful city) plus from a first-class institute - Jožef Stefan.
OPTIMAGE PARTICLES FULL
I wish to add to your excellent contribution and give you full marks for effort here.
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