DRDFunctions for MS Excel®

          These functions work in Microsoft Excelâ to implement the calculations formerly performed by the MS DOS® particle packing programs that Professors Funk and Dinger freely distributed over the last 15 years.  Those MS DOS® programs are no longer available.

          To use these functions, the DRDFunctions.XLA file should be stored in the   C:\Program Files\Microsoft Office\Office\Library    folder, and the DRDFunctions should be checked as an Add-In to MS Excelâ (within the Excel Tools Menu, select Add-Ins, and check DRDFunctions).  Once declared as an ‘add-in’, all functions will be available from the Insert Menu, Functions, User-defined. 

          Individual who use these functions must incorporate them into their own spreadsheet programs to achieve the desired calculation results.  The author of these functions is not responsible for writing, debugging, or developing operating spreadsheet programs that run within users’ computers.  These functions are being made available as a service to the ceramics community.  It is the responsibility of the individuals who purchase and use these functions to write, debug, and develop their own spreadsheet programs.

          As a Ceramics consultant, the author of these functions is available to ceramics companies if they need help to create user-specific programs using these functions.  Normal consulting fees will apply in any such cases.  Please call or e-mail for consulting fees if interested.   

          Functions contained in this package include:

CPFT_DFEq     Calculates the Cumulative Percent Finer Than (CPFT) values for Dinger-Funk particle size distributions.

CPFT_Interp    Interpolates the CPFT values for particle sizes within the measured range that are not part of the original measured distribution. 

CumeSSA    Calculates the cumulative mass Specific Surface Area (SSA) after individual surface areas have been calculated. 

CumeVSA     Calculates the cumulative Volume specific Surface Area (VSA) after individual surface areas have been calculated.

Histo    Calculates the histogram particle size distribution values from the measured (or theoretically calculated) CPFT values.

Index_of_Size_that_Controls_Porosity    Shows the index of the particle size class that was used as the basis for the porosity calculation.  The algorithm calculates a porosity based on each particle size class in the calculation and then it selects the minimum value to report.  This function points to the size class that is associated with the porosity value reported.  It is useful because it usually points to the particle size class in the distribution that most disrupted the packing.

Log10    Calculates the base 10 logarithm of values.  Base 10 logs and charts plotted on log-log axes are common when dealing with particle size distributions.

MicronIPS    Calculates the average expected InterParticle Spacing (IPS) between particles in a suspension.  This function reports the answer in micrometers.

NanoIPS    Calculates the average expected InterParticle Spacing (IPS) between particles in a suspension.  This function reports the answer in nanometers.

NumParticles    Calculates the number of particles represented in a particle size class in a distribution.  All particles are assumed to be spheres.  

PCI    Calculates the Particle Crowding Index (PCI), which is the cumulative number of particles in a true cubic centimeter of powder, when the number of particles in each size class have already been calculated.

Porosity    Calculates the minimum expected porosity for a dense pack of a measured or calculated particle size distribution.  To compare particle size distributions, dense packing and/or minimum viscosity at a given solids content are expected to occur when this calculated porosity is a minimum.

Series2    Calculates a factor-of-2 particle size distribution series.

Series4Rt2    Calculates a fourth-root-of-2 particle size distribution series.

SeriesRt2    Calculates a square-root-of-2 particle size distribution series.

SSA    Calculates the mass Specific Surface Area (SSA) for a particle size distribution class.

VSA    Calculates the Volume specific Surface Area (VSA) for a particle size distribution class.

          Extra functions include those that are not necessary to the successful calculation of the most useful particle size distribution minimum parameters and some other functions that the author has written and included in this set.  These extra functions include:

100Extrap    Extrapolates (and completes) the histogram values to sizes below the lower measurable particle size limit of the analyzer used. 

100ExtrapSlope    This function calculates the slope of the extrapolation which is used with the previous function.

HExtrap    Extrapolates (and completes) the histogram values to sizes below the lower measurable particle size limit of the analyzer used.  This function forces the calculated SSA value to be equal to the measured SSA value.  

HExtrapSlope    This function calculates the slope of the extrapolation which is used with the previous function.  As mentioned above, this function forces the calculated SSA value to equal the measured SSA value.  Although SSA measurement techniques see and measure all contained surface areas, particle size analyzers have lower size measurement limits that prevent them from seeing all particles (especially the colloids).  These HExtrap functions perform a linear extrapolation to the lowest particle size (Ds) and the slope of this extrapolation line is the appropriate value to cause the calculated and measured surface areas to agree.

Smooth2ndDeg    This function fits a second degree polynomial (using least squares techniques) to a series of X,Y data points.  From the resulting polynomial, it then calculates the Y value at the desired X.   The value returned by this function will be in the same units as the other Y data points.  This function can be used to smooth sets of data.  It can also be used to reduce the number of data points in the data set as the smoothing takes place.  For instance, this function can smooth each point in a set of data that includes 200 raw data points.  Alternatively, it can smooth every 10 points in the data set and return one value at the center of the interval to replace the 10 points.  Used in this way, this function can convert a 200-point data set to a smoothed, 20-point data set.  

TypeS_DegC    This function calculates the temperature in degrees C that corresponds to the emf (mV) of a type S thermocouple.

TypeS_EMF    This function calculates the emf (mV) for a type S thermocouple at T degrees C.

          As the author writes new functions, they will be added to (and made available with) this function set.

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