High School

How to manually calculate \(\frac{dN}{d\log D_p}\) from APS data when the output is the particle diameter and the \(dN\):

a. Define APS and \(\frac{dN}{d\log D_p}\).

b. Explain the manual calculation process step by step.

c. Discuss the significance of \(\frac{dN}{d\log D_p}\) in particle analysis.

d. Compare manual calculation with automated methods.

Answer :

Final answer:

The Aerodynamic Particle Sizer (APS) measures particle sizes and concentrations. dN/dlogDp represents the number of particles per logarithmic interval of diameter, valuable for particle distribution analysis. Automated methods are preferred over manual calculation due to efficiency and accuracy.

Explanation:

(A) Defining APS and dN/dlogDp

Aerodynamic Particle Sizer (APS) is an instrument used to measure the aerodynamic diameter of particles. This is typically used in particle technology fields like aerosol research. The term dN/dlogDp refers to the differential number concentration divided by the logarithm change in the particle diameter (Dp), essentially representing the number of particles within a specific size range in a logarithmic scale.

(B) Manual Calculation Process


  3. Collect APS data which provides particle diameter and number concentration (dN).

  6. Arrange the data in order of increasing diameter.

  9. Calculate the difference in the logarithm of adjacent particle diameters (dlogDp).

  12. Divide the number concentration difference (dN) by dlogDp to obtain dN/dlogDp for each size bin.

(C) Significance of dN/dlogDp in Particle Analysis

The parameter dN/dlogDp is significant as it provides information on the number distribution of particles across different size ranges, which is vital for understanding and controlling the nature of particulate matter in various environments and industrial processes.

(D) Manual vs Automated Calculation

While manual calculation of dN/dlogDp is possible, it is time-consuming and more prone to error compared to automated methods. Automated software associated with APS can quickly process data, deliver accurate results, and present them in a user-friendly format.

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