Development of an open-ended microstrip stub apparatus and technique for the dielectric characterization of powders

Abstract

Please cite this article as: Muhammad Y. Sandhu,IanC.Hunter,NigelS.Roberts,Development of an open-ended microstrip stub apparatus and technique for the dielectric characterization of powders, Powder Technology (2016Technology ( ), doi: 10.1016Technology ( /j.powtec.2016 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT AbstractA new apparatus and method to characterize the complex dielectric permittivity of powders is described. The complex permittivity of a range of detergent powder agglomerates with different moisture levels, at ambient and elevated temperatures, has been determined using this technique. Results are consistent with A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT2 predictions of how the water interacts with the different components of the detergent particles at these different conditions.

The process for making low density LAS surfactant detergent agglomerates using microwave heating

“…The loss factors and dielectric constants of the surfactant agglomerates were measured at room temperature using an open circuit microstrip stub partly loaded with the powder material [12]. The complex dielectric properties were determined by measuring the scattering parameters of a two port microstrip bandstop resonator and then replicating these results by simulation using the electromagnetic simulation tool Ansoft HFSS (High Frequency Structure Simulator).…”

“…Relative dielectric constants and loss factors were calculated from the relative shifts in frequency and dielectric absorption [12]. The dielectric properties of the agglomerate samples varied with the moisture level.…”

Microwave power absorption profile of detergent surfactant agglomerates during microwave heating

“…Following conditioning, the dielectric properties of the different agglomerate samples were measured and the samples then exposed to microwave heating. The loss factor and dielectric constant of the LAS agglomerate sample were measured using an open circuited microstrip stub partly loaded with the sample as described in [12]. between the heating applicator and the water load.…”

“…However, the materials within detergent agglomerate can have complex phase behaviors with a range of crystalline, liquid crystalline and amorphous phases being present dependent on factors such as concentration, available water level, presence of electrolytes etc. Only the "free" water contributes to the dielectric properties of the material [12]. Water tied up in crystalline hydrates is not able to interact with the microwaves and hence does not contribute to heating.…”