What is the difference between number average and weight average molecular weights?

What is the difference between number average and weight average molecular weights?

The number average molecular weight is the total weight of the sample divided by the number of molecules in the sample. To get the number average molecular weight you divide the total weight of the sample by the total number of the molecules.

What is average particle size?

One can determine the average particle size of a solid from a knowledge of its surface area per unit weight and its density; for if the particles are considered to be uniform spheres, then the ratio of volume to area is r/3, where r is the radius of the equivalent sphere.

What is PDI value?

PdI is defined as the standard deviation (σ) of the particle diameter distribution divided by the mean particle diameter. P d I = ( σ 2 a ) 2 . (3) PdI is used to estimate the average uniformity of a particle solution, and larger PdI values correspond to a larger size distribution in the particle sample.

What is PDI in particle size?

PDI is basically a representation of the distribution of size populations within a given sample. The numerical value of PDI ranges from 0.0 (for a perfectly uniform sample with respect to the particle size) to 1.0 (for a highly polydisperse sample with multiple particle size populations).

How is PDI calculated?

The pdi for that peak is the square of the standard deviation divided by the square of the mean. As an example consider the peak was at a mean size of 9.3nm and the st dev was 4.4nm. As a result then the pdi for this peak would be: 4.4*4.4/(9.3*9.3) = 0.22.

What is zeta potential of nanoparticles?

Zeta potential is a measure of the effective electric charge on the nanoparticle surface. The magnitude of the zeta potential provides information about particle stability, with particles with higher magnitude zeta potentials exhibiting increased stability due to a larger electrostatic repulsion between particles.

What is particle size distribution curve?

The particle-size distribution (PSD) of a powder, or granular material, or particles dispersed in fluid, is a list of values or a mathematical function that defines the relative amount, typically by mass, of particles present according to size. particles into the PSD that is then called a grain size distribution.

What is the purpose of particle size distribution curve?

The data obtained from grain size distribution curves is used in the design of filters for earth dams and to determine suitability of soil for road construction, air field etc. Information obtained from grain size analysis can be used to predict soil water movement although permeability tests are more generally used.

Why do we do particle size distribution?

Particle size distribution can be an important physical property or cleanliness indicator for a variety of manufactured products across many industries. For many manufacturers, measuring particle size distribution helps ensure products are free of contamination.

What is the purpose of particle size distribution?

Particle size distribution, also known as gradation, refers to the proportions by dry mass of a soil distributed over specified particle-size ranges. Gradation is used to classify soils for engineering and agricultural purposes, since particle size influences how fast or slow water or other fluid moves through a soil.

What is the principle of particle size distribution?

It works on the principle that when a beam of light (a laser) is scattered by a group of particles, the angle of light scattering is inversely proportional to particle size (ie. the smaller the particle size, the larger the angle of light scattering).

Which is the following is the widely used method for particle size analysis?

Sieve analysis

What does D10 particle size mean?

D10: The portion of particles with diameters smaller than this value is 10% D50: The portions of particles with diameters smaller and larger than this value are 50%. Also known as the median diameter. D90: The portion of particles with diameters below this value is 90%.

What is D97 particle size?

D97 is particle diameter value where 97% of the sample is smaller than that value. It is useful for determining the upper limit to the particle size distribution. 97 is a percentage that means 97% percent. In an AimSizer Particle Size Analysis Result Report, the D97 is represent as D97.

How is D10 D30 D60 calculated?

The particle diameters defining 10%, 30%, and 60% finer from the grain-size distribution curve are estimated as: D10 = 0.14 mm , D30 = 0.27 mm, and D60 = 0.42 mm.

What is D10 and D60?

D60 – 60 % of the soil particles are finer than this size. D30 – 30% of the particles are finer than this size. D10 – 10% of the particles are finer than this size. For example, if you have 100 particles of diameter ranging from 1 mm to 100 mm, D60 is 61 mm (below which 60% of particles are there).

Why is the hydrometer analysis not used for sand?

The largest opening size used was 2 mm so it was impossible to fully test if the soil sample was completely well-graded or not, but between the sieve and hydrometer analysis, the soil ranged from a particle size of around . This law consists of many assumptions that are not valid for hydrometer analysis.

What is a gradation curve?

The S-curve (often referred to as a gradation curve diagram) is logarithmic graphical representation of cumulative percent passing of grains on the y-axis, and the sieve size opening on the x-axis.

What is the coefficient of curvature?

It is the parameter estimated using the gradation curve through sieve analysis. The diameter taken from gradation curve for which the 10% particles are finer is known as effective size. When the value of C C is in between 1 and 3, the sand or gravel is said to be well graded.

What is CC and CU?

The uniformity coefficient (Cu), curvature coefficient (Cc) and the effective size (D10) are the grading characteristics of the soil. These are the geometric properties of a grading curve that describe a particular type of soil.

What is uniformity coefficient of sand?

The uniformity coefficient describes how similar in size the sand particles are. The silt content is the percentage of sand with a diameter < 0.1 mm. If your effective size is below 0.15 mm, that means too much of the sand is very small sand particles. This will lead to a low flow rate.

What is effective size of sand?

The effective size (D10) and uniformity coefficient (Uc) are the principal characteristics of granular media treatment systems. The ideal sand media for intermittent sand filters is a coarse sand with an effective size between 0.3 mm and 0.5 mm.

Can sand go through a sieve?

Sieving. A mixture made of solid particles of different sizes, for example sand and gravel, can be separated by sieving.

What is CC soil?

The uniformity coefficient (Cu) and the coefficient of gradation (Cc) are the measures of soil gradation. These coefficients help to classify the soil as well graded or poorly graded ones.

What is the most basic classification of soil?

Coarse grained soils are those with more than 50% of the material larger than 0.075mm size. Coarse grained soils are further classified into gravels (G) and sands (S)….(iv) Unified Soil Classification System.

Soil Soil Component Symbol
Coarse Grained Sand S
Fine Grained Silt M
Clay C
Organic Matter O

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