Paper about x-ray microwave calorimetry in Thermochimica Acta

A new paper entitled “Microwave calorimetry using X-rays” has just been published in the scientific journal Thermochimica Acta. The paper describes some recent experimental results of the Electromagnetic Wave Processing Group of the Swiss Federal Laboratories for Materials Testing and Research – EMPA- in collaboration with the Microwave Area of the Institute ITACA.

An alternative approach for microwave calorimetry is proposed which relies on the synchrotron radiation powder diffraction technique as well as on the Grüneisen formalism for the analysis of thermal expansion. Cobalt was selected as suitable magnetic material for the present evaluation of the method. First results are reported concerning the calorimetric assessment of the HCP (hexagonal close-packed) to FCC (face centered cubic) transition of cobalt from in situ time-resolved X-ray diffraction experiments performed during magnetic (H-field) microwave heating.

The X-ray calorimetry method yields specific heat capacity estimations that compare well with results from conventional differential scanning calorimetry measurements. In the presence of the 2.45 GHz microwave H-field, an ‘anomalous’ behaviour of the heat capacity across the structural phase transition is detected, which can be correlated with the magnetic spin reorientation transition of cobalt in the same temperature range.

The paper is published on line and it is available in the website of Thermochimica Acta.

For more information about the experiments described in the paper, please contact directly with the authors.

AMPERE conference about Microwave and HF heating

The 13th International Conference on Microwave and High Frequency Heating on behalf of the Ampere Association (AMPERE Conference) was held from 5 to 8 September 2011 at the “Ecole National Supérieure d’Electrotechnique, d’Electronique, d’Informatique, d’Hydraulique et des Télécommunications de Toulouse” (ENSEEIHT), France.

The conference, held every 2 years, was an excellent occasion for academic researchers and engineers from industries to show the latest achievements, to exchange innovative ideas of research, and to promote the most recent advanced investigations in the applications of microwave and high frequency technologies at laboratory and industrial level.

Researchers of the Microwave Division (DIMAS) participated in the organization of the conference, in the technical program and in the exhibition section. The following picture shows some DIMAS researchers in the exhibition room with some of the recent developments in the field of microwave measurements (portable impedance measurement system, high power impedance measurement system and dielectric kit for vials).

In the technical program, DIMAS participated with contributions in the oral sessions and poster sessions with the following papers:

[1] Pedro J. Plaza-Gonzalez, Antoni J. Canos, Jose M. Catala-Civera and Jose D. Gutierrez-Cano, Complex Impedance Measurement System Around 2.45GHz in a Waveguide Portable System. Proceedings of the 13th International Conference on Microwave and RF Heating, AMPERE 2011, September 5-9, 2011, Toulouse (FRANCE), pp. 447-450. ISBN: 978.2.85428.978.7

[2] Jose M. Catala-Civera, Jose D. Gutierrez-Cano, Felipe L. Penaranda-Foix and B. Garcia-Baños, Portable System for Dielectric Characterization of Materials at Microwave Frequencies. Proceedings of the 13th International Conference on Microwave and RF Heating, AMPERE 2011, September 5-9, 2011, Toulouse (FRANCE), pp. 127-130. ISBN: 978.2.85428.978.7

[3] Felipe L. Penaranda-Foix, Pedro J. Plaza-Gonzalez, Jose M. Catala-Civera, Elias de los Reyes-Davo and B. Garcia-Baños, Perlite Expansion in a Fluidized Bed Using Microwave Energy. Proceedings of the 13th International Conference on Microwave and RF Heating, AMPERE 2011, September 5-9, 2011, Toulouse (FRANCE), pp. 235-238. ISBN: 978.2.85428.978.7

[4] Amparo Borrell, L. Garcia-Riaño, Maria Dolores Salvador, Felipe L. Penaranda-Foix and Pedro J. Plaza-Gonzalez, Microwave Sintering of Yttria-Stabilized Zirconia with High Properties. Proceedings of the 13th International Conference on Microwave and RF Heating, AMPERE 2011, September 5-9, 2011, Toulouse (FRANCE), pp. 193-196. ISBN: 978.2.85428.978.7

[5] Maria Cabanes-Sempere, Jose M. Catala-Civera, C. Cozzo, Sebastien Vaucher and M. A. Pouchon, Innovative Production of Nuclear Fuel by Microwave Internal Gelation. Theoretical microwaves-microspheres interaction. Proceedings of the 13th International Conference on Microwave and RF Heating, AMPERE 2011, September 5-9, 2011, Toulouse (FRANCE), pp. 231-234. ISBN: 978.2.85428.978.7

Short course about microwave and HF heating basics

As part of the 13th International Conference on Microwave and High Frequency Heating on behalf of the Ampere Association held in Toulouse (France), a special one-day short course on microwave processing technologies was offered on Monday September 5th, 2011.

The short course covered the basics of microwave and high frequency heating, with special focus on the fundamentals of microwave heating, operation, dielectric properties, design and modelling of microwave devices and an overview of industrial microwave applications.

Course participants came from industry and research, as well as graduate students with diverse interest in applied microwave technologies and applications.

The lectures were provided by a group of international experts from the academia and the industry in the fields of industrial microwave processing, measurements, materials, microwave devices, modelling and computational methods.

The program of the short course was the following:

Short Course: “Basics of Microwave and HF-Heating” (Monday, September 5th, 2011). Co-chaired by: J.M. Catalá-Civera / Juan Monzó Cabrera

08.30 – 08.40 Opening by Course Director: Jose M. Catala-Civera (UPV, Spain)

08.40 – 09.40 Dielectric heating basics (J Monzo, UPC, Spain)

Theoretical basis of electromagnetic propagation, sources and microwave frequencies, wave material interactions are described in this introductory lecture.

09.40 – 10.40 Dielectric properties measurement (J.M. Catala-Civera, UPV, Spain)

This lecture reviews the different dielectric property measurement techniques at microwave frequencies, ranging from the open-ended coaxial probes to more sophisticated resonators. The lecture also includes a hands-on lesson with a portable Dielectric Measurement Kit.

10.40 – 11.00 Coffee break

11.00 – 12.00 Microwave applicators design criteria (P. Veronesi, UM, Italy)

This lecture tries to answer questions as: Which kind of applicator for my process? How to estimate the overall microwave power requirements for a certain application? How many magnetrons? Continuous or batch systems? Efficiency? etc.

12.00 – 13.15 Modeling of Microwave applicators (V. Yakovlev, WPI, USA)

The lecture briefly outlines fundamental and practical issues in computer modeling of systems in microwave power engineering and shows how modern advanced simulation can help engineers in designing microwave heating applicators.

13.15 – 15.00 Lunch

15.00 – 16.30 Industrial RF and Microwave Application: a brief review (A.C. Metaxas, CU, UK)

This lecture reviews the industrial applications of RF and microwave energy, ranging from rubber curing to food tempering with microwaves and from moisture leveling of biscuits to textile drying with RF. Examples of good and bad industrial practice will be highlighted.

16.30 Questions and debate