Author Archives: Jeff Kenvin

Adding a custom model to the NLDFT library – a CO2 GCMC model for carbons

New models for determining the pore volume and pore size distribution of porous solids may be easily added to MicroActive.  These kernels developed using NLDFT, GCMC and other variants have been available for more than 20 years.  Traditionally instrument manufacturers have supplied these proprietary models.  To introduce new powerful capabilities for users, Micromeritics has developed a simple program to convert model isotherms (a kernel) to a model file that can be easily used with MicroActive.  This provides users the full capabilities of the MicroActive user interface and advanced deconvolution techniques. Continue reading

New capabilities for the 3Flex – simultaneous analysis of three samples each using a different adsorptive

The Micromeritics 3Flex design includes metal seals, hard seal valves, and both a Pirani and cold cathode vacuum gauges.  The hardware is complemented by the state of the art software which continuously monitors  the status of the instrument.  These hardware and software feautures allow 3Flex users to perform adsorption experiments that were previously unavailable in multi-port instruments.  3Flex users may characterize three samples simultaneously and each sample may use a different adsorptive.   Continue reading

Versatility is synonymous with MicroActive

MicroActive software by Micromeritics was designed to be fast, easy to use, and versatile.  These design goals translated into powerful but simple to use software.  One of the most versatile features of MicroActive is compatibility with data collected from a wide variety of instruments including all Micromeritics gas adsorption analyzers, reference data, and data from other instrument manufacturers. Continue reading

Krypton surface area and water sorption for common pharmaceutical excipients

The GAB (Guggenheim, Anderson, and de Boer) equation [1, 2, 3] is a widely referenced model that is often used for the characterization of pharmaceuticals, excipients, and food [4, 5, 6, 7].   Three excipients: lactose, gelatin, and talc were characterized in a single sorption instrument using krypton adsorption and BET modeling to determine the as-received surface area, water sorption, and then krypton sorption to determine the impact of water sorption on the BET surface area.   Continue reading

Automatic selection of data points and optimization of BET surface area

The selection of data used for fitting BET surface area is often an easy process using the MicroActive software.  A broad range of isotherm data is selected and then the BET fit may be further refined to yield the specific surface area of a material.  The process for data selection and optimization has been fully automated using the BET surface area rules advocated by Professor Jean Rouquerol, CNRS Marseille, FR.  Prof. Rouquerol recommends the following criteria:
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A simple method for combining pore size distributions calculated from gas adsorption isotherms with mercury intrusion porosimetry

MicroActive 2.0 and MicroActive for 3Flex include a powerful utility for including the pore size distribution from mercury porosimetry analyses with pore size distributions calculated from gas adsorption isotherms. This new import function allows users to rapidly view micro, meso, and macro pore size distributions in one easy to use application.

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