Synthetic hydrocarbons, generated by the Fischer-Tropsch reaction, are commonly used as fuels and lubricants. In the F-T reaction, syngas (a mixture of carbon monoxide (CO) and hydrogen (H2)) flows into a reactor loaded with a cobalt, iron, or nickel catalyst. The products are the liquid hydrocarbon and water. This process is typically done in a large scale reactor and requires a separation mechanism to remove the water. Now, the Particulate Systems Microactivity Effi and its patented liquid/liquid/gas separator brings this reaction to the bench-top. Continue reading
Metal powders are used in a wide variety of applications. Many of the items we use on a daily basis include parts molded using metal powders. One parameter to control the quality of the metal powders is particle or powder size, typically in the form of an average value or “Fisher number.”
A common metal powder sizing technique is by air-permeability which gives an average size. Traditionally, a Fisher Model 95 Sub-Sieve Sizer (FSSS), with a particle size range of 0.5 to 50 µm, has been used to get this average size value, or “Fisher number.” Using this technique is the basis for ASTM Standard B330-12, “Standard Test Methods for Estimating Average Particle Size of Metal Powders and Related Compounds Using Air Permeability” as well. Since the FSSS has been discontinued, industry has been clamoring to find an alternative to technique or device that gives the same results and agrees with all the historical data collected on the FSSS.
Sub-micron particles suspended in liquid medium are regularly utilized in many industries, from food and pharmaceutical production to lubricants for machinery. The stability of these suspensions is vital to their function and shelf-life. The typical way to characterize the stability of a suspension is to measure the zeta potential of the suspension.
So what is zeta potential and how is it used to determine suspension stability? Continue reading
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
Micromeritics Instrument Corporation is proud to announce its national accreditation as a Post-Secondary Avocational/Professional Development Institution by the Accrediting Council for Continuing Education and Training (ACCET), an accrediting agency recognized by the United States Department of Education. Attendees of Micromeritics Learning Center courses can now earn nationally accredited Continuing Education Units (CEUs) for completion of instrument operator training. As a result of this prestigious recognition, Micromeritics Learning Center has relocated all its educational information and training to www.micro.edu . Continue reading
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: