Pub Date : 2019-09-09DOI: 10.4995/ampere2019.2019.9897
Takeko Matsumura, M. Kishihara, U. Urushihara
We have developed a flow microwave reactor with a coaxial cavity. It comprises a cylindrical cavity of 100 mm inside diameter, a metal rod along its center axis, and a spiral glass tube for flowing solvents and reactants, as shown in Fig.1. When the input port of microwave is placed at the end of the metal rod, the TEM mode is excited in the cylindrical chamber due to the presence of the metal rod. Simulations of the electric field and the magnetic field within the coaxial cavity are shown in Fig.2. This configuration was confirmed suitable for rapid and continuous microwave syntheses of various functional metal complexes. Experimental results are presented of Ir(Ⅲ) complexes for OLED dopants and Ru(Ⅱ) complexes for various sensors. The application to rapid and continuous microwave synthesis of various functional metal complexes were performed in success. In the similar manner as the coaxial reaction chamber of 2.45GHz, a coaxial reaction chamber for 5.8GHz IMS band, dimension of 51mm in diameter and 50mm in height, is designed The electric field distributions in the chamber and the temperature profiles of solvent are simulated using the commercial simulator (COMSOL Multiphysics) for 5.8 GHz, 5W microwave input. Using the simulation results appropriate dimensions of the chamber are determined for the 5.8 GHz operation. When water is used as a solvent the simulation shows that the temperature rises from20℃ to 95℃ after 300 seconds of the microwave irradiation.
{"title":"Development of Coaxial Type flow microwave reactor and application to microwave reactions.","authors":"Takeko Matsumura, M. Kishihara, U. Urushihara","doi":"10.4995/ampere2019.2019.9897","DOIUrl":"https://doi.org/10.4995/ampere2019.2019.9897","url":null,"abstract":"We have developed a flow microwave reactor with a coaxial cavity. It comprises a cylindrical cavity of 100 mm inside diameter, a metal rod along its center axis, and a spiral glass tube for flowing solvents and reactants, as shown in Fig.1. When the input port of microwave is placed at the end of the metal rod, the TEM mode is excited in the cylindrical chamber due to the presence of the metal rod. Simulations of the electric field and the magnetic field within the coaxial cavity are shown in Fig.2. This configuration was confirmed suitable for rapid and continuous microwave syntheses of various functional metal complexes. Experimental results are presented of Ir(Ⅲ) complexes for OLED dopants and Ru(Ⅱ) complexes for various sensors. The application to rapid and continuous microwave synthesis of various functional metal complexes were performed in success. In the similar manner as the coaxial reaction chamber of 2.45GHz, a coaxial reaction chamber for 5.8GHz IMS band, dimension of 51mm in diameter and 50mm in height, is designed The electric field distributions in the chamber and the temperature profiles of solvent are simulated using the commercial simulator (COMSOL Multiphysics) for 5.8 GHz, 5W microwave input. Using the simulation results appropriate dimensions of the chamber are determined for the 5.8 GHz operation. When water is used as a solvent the simulation shows that the temperature rises from20℃ to 95℃ after 300 seconds of the microwave irradiation.","PeriodicalId":277158,"journal":{"name":"Proceedings 17th International Conference on Microwave and High Frequency Heating","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131061491","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-09-09DOI: 10.4995/ampere2019.2019.9757
Steffen Pauly, A. Schulz, M. Walker, G. Tovar, M. Balk, Joachim Schneider, K. Baumgärtner
The aim of the study is to optimize an existing microwave powered remote plasma source (RPS) with respect to the etching rate and gas temperature and to simplify the setup to save production costs. The RPS, which is shown in figure 1, is a low-pressure plasma source where the plasma is generated and exists mainly in the chamber of the source. Only radicals migrate out of the RPS. This is one important feature, that the plasma source is used for etching processes when ion bombardment and high thermal strain of the substrate must be prevented. The etching process is a chemical process, where the radicals react with the substrate surface atoms forming gaseous molecules. The benefit is a damage-free, dry and clean substrate surface. To achieve these goals, a FEM-based model of the RPS has been developed to investigate the microwave distribution and the microwave coupling into the plasma chamber, as well as the plasma itself. In this paper different examples of FEM based microwave simulations by different conditions and their experimental validations will be presented. To compare the calculated electric field distribution in the RPS with the real field distribution, PMMA-substrates were placed inside the plasma chamber of the source. They are heated up by the electric field and evaluated with an infrared camera and liquid crystal sheets. Both the measured and the calculated field distribution show a very good conformity. When the electric field is high enough in the plasma chamber the plasma ignites, the electron density and thus the permittivity and the conductivity increase, which changes again the electric field distribution. For this purpose, the FEM-model has been extended by the Drude model1. The model considers the equation of motion with a damping term for the electrons, leading to an expression for the conductivity. Results for various electron densities as well as their corresponding electric field distributions are presented and compared with optical measurements. Fig. 1. The figure shows the scheme of the RPS with its main components and functions.
{"title":"Modelling and Study of a Microwave Plasma Source for High-rate Etching","authors":"Steffen Pauly, A. Schulz, M. Walker, G. Tovar, M. Balk, Joachim Schneider, K. Baumgärtner","doi":"10.4995/ampere2019.2019.9757","DOIUrl":"https://doi.org/10.4995/ampere2019.2019.9757","url":null,"abstract":"The aim of the study is to optimize an existing microwave powered remote plasma source (RPS) with respect to the etching rate and gas temperature and to simplify the setup to save production costs. The RPS, which is shown in figure 1, is a low-pressure plasma source where the plasma is generated and exists mainly in the chamber of the source. Only radicals migrate out of the RPS. This is one important feature, that the plasma source is used for etching processes when ion bombardment and high thermal strain of the substrate must be prevented. The etching process is a chemical process, where the radicals react with the substrate surface atoms forming gaseous molecules. The benefit is a damage-free, dry and clean substrate surface. To achieve these goals, a FEM-based model of the RPS has been developed to investigate the microwave distribution and the microwave coupling into the plasma chamber, as well as the plasma itself. In this paper different examples of FEM based microwave simulations by different conditions and their experimental validations will be presented. To compare the calculated electric field distribution in the RPS with the real field distribution, PMMA-substrates were placed inside the plasma chamber of the source. They are heated up by the electric field and evaluated with an infrared camera and liquid crystal sheets. Both the measured and the calculated field distribution show a very good conformity. When the electric field is high enough in the plasma chamber the plasma ignites, the electron density and thus the permittivity and the conductivity increase, which changes again the electric field distribution. For this purpose, the FEM-model has been extended by the Drude model1. The model considers the equation of motion with a damping term for the electrons, leading to an expression for the conductivity. Results for various electron densities as well as their corresponding electric field distributions are presented and compared with optical measurements. Fig. 1. The figure shows the scheme of the RPS with its main components and functions.","PeriodicalId":277158,"journal":{"name":"Proceedings 17th International Conference on Microwave and High Frequency Heating","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114491923","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-09-09DOI: 10.4995/ampere2019.2019.9893
S. Kumari, Sujoy Kumar Samanta, Kush Patel
The exigencies of a swift, qualitative and economical procedure for the food industry was addressed by the microwave assisted processing such as heating, drying, thawing, etc1. A food material in itself is a complex sample with multiple components and varying dielectric properties which makes its mathematical modeling arduous. The most realistic approach is to consider the food as a porous dielectric which basically consists of a continuous phase and one or more dispersed phases2. The porous dielectrics considered for this study is meat as the continuous phase and oil, water or air as dispersed phase. A theoretical analysis has been performed to study the thermal effects on the 2D cylindrical porous food dielectrics subjected to microwave irradiation. The analysis comprises of different porosity conditions (Φ = 0.1, 0.25 and 0.4), different initial intensities (I0 = 1 and 1.5 Wcm-2) and different dispersed phases. Galerkin finite element analysis has been used to solve electric field and energy balance equations with suitable boundary conditions.
{"title":"ENHANCED MICROWAVE ASSISTED PROCESSING OF 2D CYLINDRICAL POROUS FOOD DIELECTRIC","authors":"S. Kumari, Sujoy Kumar Samanta, Kush Patel","doi":"10.4995/ampere2019.2019.9893","DOIUrl":"https://doi.org/10.4995/ampere2019.2019.9893","url":null,"abstract":"The exigencies of a swift, qualitative and economical procedure for the food industry was addressed by the microwave assisted processing such as heating, drying, thawing, etc1. A food material in itself is a complex sample with multiple components and varying dielectric properties which makes its mathematical modeling arduous. The most realistic approach is to consider the food as a porous dielectric which basically consists of a continuous phase and one or more dispersed phases2. The porous dielectrics considered for this study is meat as the continuous phase and oil, water or air as dispersed phase. A theoretical analysis has been performed to study the thermal effects on the 2D cylindrical porous food dielectrics subjected to microwave irradiation. The analysis comprises of different porosity conditions (Φ = 0.1, 0.25 and 0.4), different initial intensities (I0 = 1 and 1.5 Wcm-2) and different dispersed phases. Galerkin finite element analysis has been used to solve electric field and energy balance equations with suitable boundary conditions.","PeriodicalId":277158,"journal":{"name":"Proceedings 17th International Conference on Microwave and High Frequency Heating","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125037976","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-09-09DOI: 10.4995/ampere2019.2019.9895
Y. Kanematsu, Takeko Matsumura
It has been realized that various chemical reactions are accelerated under irradiation of MW. Such Microwave chemistry is known as time-saving, clear and eco-friendly. MW ovens are world-wide domestic tools for cooking which can serve meals quickly. Regardless of its convenience, few understand the essential mechanism of MW ovens. For better understanding of MW chemistry, authors think it is necessary for to introduce elementary knowledge by holding a 1-day program of experiments by using microwave (MW) ovens.“Science with microwave oven”, 1-day program which we developed and named “Hirameki Tokimeki Science” was supported by Japan Society for the promotion of Science, has been performed over four years.More than 100 students of elementary and junior-high school have joined the program.Here we report the program, response from students.Program of experiments: “1: Dyeing handkerchief with onion peer (*1), 2: Cooking of pizza quickly yeast-leavened, 3: Preparation of shining slime with fluorescein dye synthesized in nonsolvent reaction. 4. Plasma in MW oven (*2), etc.”Students realized how MW accelerated chemical reactions and that dyeing under MW was faster and more fixed compared with the conventional methods. Besides, they could enjoy lunch with pizza and dealing with the slime, both they made. They had a good time with a bit of scientific knowledge. Through 1-day program, we can make science more familiar with students, and it will cause young students to become more interested in science, lead them to future research workers.In addition to the “Hirameki Tokimeki (Inspiration and Spark) Program, we have doneVolunteer activities at Ishinomaki, one of the most damaged cities at the Higashi Nihon Big Earthquake, in 2011.“Science with microwave oven” program surely gives students mysterious interest anddream for Science. That is “Inspire and Spark!” (*1) (*2)
{"title":"DO A SCIENCE EXPERIMENT FOR FUTURE SCIENTISTS","authors":"Y. Kanematsu, Takeko Matsumura","doi":"10.4995/ampere2019.2019.9895","DOIUrl":"https://doi.org/10.4995/ampere2019.2019.9895","url":null,"abstract":"It has been realized that various chemical reactions are accelerated under irradiation of MW. Such Microwave chemistry is known as time-saving, clear and eco-friendly. MW ovens are world-wide domestic tools for cooking which can serve meals quickly. Regardless of its convenience, few understand the essential mechanism of MW ovens. For better understanding of MW chemistry, authors think it is necessary for to introduce elementary knowledge by holding a 1-day program of experiments by using microwave (MW) ovens.“Science with microwave oven”, 1-day program which we developed and named “Hirameki Tokimeki Science” was supported by Japan Society for the promotion of Science, has been performed over four years.More than 100 students of elementary and junior-high school have joined the program.Here we report the program, response from students.Program of experiments: “1: Dyeing handkerchief with onion peer (*1), 2: Cooking of pizza quickly yeast-leavened, 3: Preparation of shining slime with fluorescein dye synthesized in nonsolvent reaction. 4. Plasma in MW oven (*2), etc.”Students realized how MW accelerated chemical reactions and that dyeing under MW was faster and more fixed compared with the conventional methods. Besides, they could enjoy lunch with pizza and dealing with the slime, both they made. They had a good time with a bit of scientific knowledge. Through 1-day program, we can make science more familiar with students, and it will cause young students to become more interested in science, lead them to future research workers.In addition to the “Hirameki Tokimeki (Inspiration and Spark) Program, we have doneVolunteer activities at Ishinomaki, one of the most damaged cities at the Higashi Nihon Big Earthquake, in 2011.“Science with microwave oven” program surely gives students mysterious interest anddream for Science. That is “Inspire and Spark!” (*1) (*2) ","PeriodicalId":277158,"journal":{"name":"Proceedings 17th International Conference on Microwave and High Frequency Heating","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130973444","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-09-09DOI: 10.4995/ampere2019.2019.9829
P. Fiedor, J. Ortyl, Mariusz Galek
Fluorescent molecular probes become interesting analytical tools in determination and labeling of chemical compounds and physical properties such as viscosity and polarity. Currently known fluorescent molecular probes can selectively and regardless of the environment detect only few molecules, and applicability in determination of micro- viscosity and micro-polarity are limited to narrow range and specific condition, therefore design and synthesis of novel molecular probes with extended range of operation are highly needed [1]. Traditional synthesis of 2-amino-4,6-diphenyl-pyridine-3-carbonitrile’s requires two step reaction with long heating time or and toxic solvent. By application of microwave irradiation, reaction time can be firmly shortened with the same or higher efficiency [2]. Derivatives of 2-amino-4,6-diphenyl-pyridine-3-carbonitrile can find application in different fields of science. Depending on the structure of fluorophore, those compounds exhibit high sensitivity to changes in polarity and viscosity of environment, also concentration of specific cations, and pH can be determined by measuring of fluorescence spectrum.
{"title":"MICROWAVE-ASSISTED SYNTHESIS AND SPECTROSCOPIC PROPERTIES OF NOVEL PYRIDINE-BASED FLUORESCENT MOLECULAR PROBES","authors":"P. Fiedor, J. Ortyl, Mariusz Galek","doi":"10.4995/ampere2019.2019.9829","DOIUrl":"https://doi.org/10.4995/ampere2019.2019.9829","url":null,"abstract":"Fluorescent molecular probes become interesting analytical tools in determination and labeling of chemical compounds and physical properties such as viscosity and polarity. Currently known fluorescent molecular probes can selectively and regardless of the environment detect only few molecules, and applicability in determination of micro- viscosity and micro-polarity are limited to narrow range and specific condition, therefore design and synthesis of novel molecular probes with extended range of operation are highly needed [1]. Traditional synthesis of 2-amino-4,6-diphenyl-pyridine-3-carbonitrile’s requires two step reaction with long heating time or and toxic solvent. By application of microwave irradiation, reaction time can be firmly shortened with the same or higher efficiency [2]. Derivatives of 2-amino-4,6-diphenyl-pyridine-3-carbonitrile can find application in different fields of science. Depending on the structure of fluorophore, those compounds exhibit high sensitivity to changes in polarity and viscosity of environment, also concentration of specific cations, and pH can be determined by measuring of fluorescence spectrum.","PeriodicalId":277158,"journal":{"name":"Proceedings 17th International Conference on Microwave and High Frequency Heating","volume":"87 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122560623","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-09-09DOI: 10.4995/ampere2019.2019.9782
V. Bilik
A Rieke diagram [1] is a magnetron characteristic that visualizes the dependence of the generated frequency fg and the net delivered power PL on the load reflection coefficient GR. GR is defined in a specific magnetron-to-waveguide coupling structure called the standard or reference launcher (Fig. 1). The diagram is plotted as a family of isolines of constant fg and of constant PL in the polar diagram of GR. Rieke diagrams are essential in the design of applications without isolators, such as domestic or professional microwave ovens. Constructing Rieke diagrams is tedious, time-consuming and equipment-demanding [2], [3], preventing systematic studies of their dependence on operating conditions, such as anode voltage and its ripple, filament current, mounting repeatability, etc. We have devised a procedure, centering around a high-power automatic impedance matching device (autotuner), which enables fully automatic measurement and plotting of the stated dependences. A block diagram of the setup is shown in Fig. 1. The autotuner, when terminated in a match (waterload), can accomplish a task inverse to impedance matching: realizing any desired reflection coefficient GR. The measurement consists of stepping through a grid of n suitably chosen reflection coefficients GR = xR + jyR, covering a desired area of the polar diagram. Each GR is measured accurately by the autotuner, along with the corresponding fg and PL. Thus, raw data for constructing a Rieke diagram are obtained, the data consisting of a collection of n points {GR, fg, PL}i, i = 1…n, with GR, in general, irregularly scattered in the complex plane. A dedicated MATLAB routine then reads the data, sorts them out to create tabulated functions fg = f(xR, yR), PL = f(xR, yR), approximates these by a 2D spline, and uses the splines to plot smoothed isocontours for chosen constant values of fg and PL, completing thus the desired Rieke diagram construction. We will present details of this procedure as well as real-life examples. Fig. 1. Rieke diagram measurement setup. References Meredith, R. J., Engineers' Handbook of Industrial Microwave Heating, London: The IEE, 1998, 250–270. Takahashi, H., I. Namba, K. Akiyama, J. Microwave Power, 1979, 14, 261–267.Yixue, W., Z. Zhaotang, Proc. ICMMT'98, 1998, 795–798.
{"title":"Automatic Measurement of Magnetron Rieke Diagrams","authors":"V. Bilik","doi":"10.4995/ampere2019.2019.9782","DOIUrl":"https://doi.org/10.4995/ampere2019.2019.9782","url":null,"abstract":"A Rieke diagram [1] is a magnetron characteristic that visualizes the dependence of the generated frequency fg and the net delivered power PL on the load reflection coefficient GR. GR is defined in a specific magnetron-to-waveguide coupling structure called the standard or reference launcher (Fig. 1). The diagram is plotted as a family of isolines of constant fg and of constant PL in the polar diagram of GR. Rieke diagrams are essential in the design of applications without isolators, such as domestic or professional microwave ovens. Constructing Rieke diagrams is tedious, time-consuming and equipment-demanding [2], [3], preventing systematic studies of their dependence on operating conditions, such as anode voltage and its ripple, filament current, mounting repeatability, etc. We have devised a procedure, centering around a high-power automatic impedance matching device (autotuner), which enables fully automatic measurement and plotting of the stated dependences. A block diagram of the setup is shown in Fig. 1. The autotuner, when terminated in a match (waterload), can accomplish a task inverse to impedance matching: realizing any desired reflection coefficient GR. The measurement consists of stepping through a grid of n suitably chosen reflection coefficients GR = xR + jyR, covering a desired area of the polar diagram. Each GR is measured accurately by the autotuner, along with the corresponding fg and PL. Thus, raw data for constructing a Rieke diagram are obtained, the data consisting of a collection of n points {GR, fg, PL}i, i = 1…n, with GR, in general, irregularly scattered in the complex plane. A dedicated MATLAB routine then reads the data, sorts them out to create tabulated functions fg = f(xR, yR), PL = f(xR, yR), approximates these by a 2D spline, and uses the splines to plot smoothed isocontours for chosen constant values of fg and PL, completing thus the desired Rieke diagram construction. We will present details of this procedure as well as real-life examples. Fig. 1. Rieke diagram measurement setup. References Meredith, R. J., Engineers' Handbook of Industrial Microwave Heating, London: The IEE, 1998, 250–270. Takahashi, H., I. Namba, K. Akiyama, J. Microwave Power, 1979, 14, 261–267.Yixue, W., Z. Zhaotang, Proc. ICMMT'98, 1998, 795–798.","PeriodicalId":277158,"journal":{"name":"Proceedings 17th International Conference on Microwave and High Frequency Heating","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134360335","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-09-09DOI: 10.4995/ampere2019.2019.10234
S. Yanagida, Takeko Matsumura
Under irradiance of 1kW-MW, nickel oxide (Ni(II)O, 25 gr)) can heat up to 1,300°C in 6 min, while ferric oxide (Fe(III)2O3, 25gr) up to 88°C in 30 min. Since Ni(II) and Fe(III) have unpaired electron (spin) of respective 2 and 5, the big difference in the MW heating speed must be explained by thermo-upconversion mechanism as recently verified for quick MW heating of water clusters.1) MW heating power by magnetic loss factor of magnetic metal oxides with unpaired electron, i.e., spin dcould not rationalize such heating-speed and temperature difference. Density functional theory-based molecular modeling(DFT/MM, B3LYP, 6-31G*) of NiO-tetramer of [(NiO)2]2 is successfully carried out with negative heat of formation, giving effective absorption in both FIR and IR regions, which verifies that Ni(II)O should be heated up through thermo-upconversion to the IR region via radio-, MW- and FIR-absorption, i.e., FIR/IR absorption and thermal IR dissipation
{"title":"Quantum chemistry molecular modeling for radio-frequency and microwave- frequency thermo-upconversion heating of metal oxides of NiO and Fe2O3","authors":"S. Yanagida, Takeko Matsumura","doi":"10.4995/ampere2019.2019.10234","DOIUrl":"https://doi.org/10.4995/ampere2019.2019.10234","url":null,"abstract":"Under irradiance of 1kW-MW, nickel oxide (Ni(II)O, 25 gr)) can heat up to 1,300°C in 6 min, while ferric oxide (Fe(III)2O3, 25gr) up to 88°C in 30 min. Since Ni(II) and Fe(III) have unpaired electron (spin) of respective 2 and 5, the big difference in the MW heating speed must be explained by thermo-upconversion mechanism as recently verified for quick MW heating of water clusters.1) MW heating power by magnetic loss factor of magnetic metal oxides with unpaired electron, i.e., spin dcould not rationalize such heating-speed and temperature difference. Density functional theory-based molecular modeling(DFT/MM, B3LYP, 6-31G*) of NiO-tetramer of [(NiO)2]2 is successfully carried out with negative heat of formation, giving effective absorption in both FIR and IR regions, which verifies that Ni(II)O should be heated up through thermo-upconversion to the IR region via radio-, MW- and FIR-absorption, i.e., FIR/IR absorption and thermal IR dissipation","PeriodicalId":277158,"journal":{"name":"Proceedings 17th International Conference on Microwave and High Frequency Heating","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134607029","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-09-09DOI: 10.4995/ampere2019.2019.9651
G. Torgovnikov, G. Brodie
EXPERIMENTAL STUDY OF MICROWAVE SLOW WAVE COMB AND CERAMIC APPLICATORS FOR SOIL TREATMENT AT FREQUENCY 2.45 GHZ. G. Brodie and G. Torgovnikov University of Melbourne, 4 Water St, Creswick, Victoria 3363, Australia; e-mail: grigori@unimelb.edu.au Keywords: ceramic applicator, comb applicator, microwave, slow wave, soil microwave treatment In many cases in industry it is required to heat or treat surface layers of different material (soil, timber, concrete, plastics and so on) with microwaves (MW). Traditional MW irradiators (antennas) cannot provide heating only in the surface areas and energy penetrates deep into the material, where it decays exponentially due to normal attenuation. Therefore, energy losses, if a heating depth of 20 - 40 mm (for example to heat soil for killing weed seeds) is all that is required, are very significant. Therefore, it is required to develop special MW applicators for surface treatment to increase process efficiency. To address this problem, a slow wave (which is sometimes called a "surface wave" applicator) comb and ceramic structures, was studied. The main property of slow waves is that the energy concentration is very near impedance electrode – comb or ceramic plate surface. Previously, slow wave structures were used mostly as delay lines and as interaction circuits in MW vacuum devices, and their properties were explored only for these specific applications. The work objectives of this study were: design slow wave, ceramic and comb structure applicators for soil treatment at frequency 2.45 GHz;experimentally study the energy distribution from slow wave applicators in the soil;study of opportunities to use slow wave structures for surface soil layer heating; andrecommendations for practical use of new slow wave applicators. Comb and ceramic slab applicators for frequency 2.45 GHz operation were designed for the soil treatment on the bases of theoretical studies and computer modelling. The comb applicator was made from aluminium and the ceramic slab applicator was made from alumina (DC=9.8, loss tangent=0.0002). A 30 kW (2.45 GHz) microwave generator was used for experiments. Containers with soil were placed on the applicator surface. An auto tuner was used in MW system to provided good impedance matching of the generator and applicators (with soil on top). This resulted in practically no power reflection. The soil “Potting Mix Hortico”, with moisture content range 32-174% and density range 590-1070 kg/m3, was used for the experiments. Energy distribution in the soil was determined by temperature measuring in the soil using thermocouples, after MW heating. Distribution of temperature measuring points covered the whole volume of the soil along and across the applicator. Results of the experiments showed that the comb applicator provides maximum energy release in soil in the central vertical plane. The ceramic alumina applicator forms two temperature maximums in two vertical planes at a distance of about 40 mm fr
{"title":"G. Brodieand, G. Torgovnikov. EXPERIMENTAL STUDY OF MICROWAVE SLOW WAVE COMB AND CERAMIC APPLICATORS FOR SOIL TREATMENT AT FREQUENCY 2.45 GHZ","authors":"G. Torgovnikov, G. Brodie","doi":"10.4995/ampere2019.2019.9651","DOIUrl":"https://doi.org/10.4995/ampere2019.2019.9651","url":null,"abstract":"EXPERIMENTAL STUDY OF MICROWAVE SLOW WAVE COMB AND CERAMIC APPLICATORS FOR SOIL TREATMENT AT FREQUENCY 2.45 GHZ. G. Brodie and G. Torgovnikov University of Melbourne, 4 Water St, Creswick, Victoria 3363, Australia; e-mail: grigori@unimelb.edu.au Keywords: ceramic applicator, comb applicator, microwave, slow wave, soil microwave treatment In many cases in industry it is required to heat or treat surface layers of different material (soil, timber, concrete, plastics and so on) with microwaves (MW). Traditional MW irradiators (antennas) cannot provide heating only in the surface areas and energy penetrates deep into the material, where it decays exponentially due to normal attenuation. Therefore, energy losses, if a heating depth of 20 - 40 mm (for example to heat soil for killing weed seeds) is all that is required, are very significant. Therefore, it is required to develop special MW applicators for surface treatment to increase process efficiency. To address this problem, a slow wave (which is sometimes called a \"surface wave\" applicator) comb and ceramic structures, was studied. The main property of slow waves is that the energy concentration is very near impedance electrode – comb or ceramic plate surface. Previously, slow wave structures were used mostly as delay lines and as interaction circuits in MW vacuum devices, and their properties were explored only for these specific applications. The work objectives of this study were: design slow wave, ceramic and comb structure applicators for soil treatment at frequency 2.45 GHz;experimentally study the energy distribution from slow wave applicators in the soil;study of opportunities to use slow wave structures for surface soil layer heating; andrecommendations for practical use of new slow wave applicators. Comb and ceramic slab applicators for frequency 2.45 GHz operation were designed for the soil treatment on the bases of theoretical studies and computer modelling. The comb applicator was made from aluminium and the ceramic slab applicator was made from alumina (DC=9.8, loss tangent=0.0002). A 30 kW (2.45 GHz) microwave generator was used for experiments. Containers with soil were placed on the applicator surface. An auto tuner was used in MW system to provided good impedance matching of the generator and applicators (with soil on top). This resulted in practically no power reflection. The soil “Potting Mix Hortico”, with moisture content range 32-174% and density range 590-1070 kg/m3, was used for the experiments. Energy distribution in the soil was determined by temperature measuring in the soil using thermocouples, after MW heating. Distribution of temperature measuring points covered the whole volume of the soil along and across the applicator. Results of the experiments showed that the comb applicator provides maximum energy release in soil in the central vertical plane. The ceramic alumina applicator forms two temperature maximums in two vertical planes at a distance of about 40 mm fr","PeriodicalId":277158,"journal":{"name":"Proceedings 17th International Conference on Microwave and High Frequency Heating","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121954724","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-09-09DOI: 10.4995/ampere2019.2019.9861
A. Trifan, I. Călinescu, M. Vinatoru, A. Gavrila
Efficient processing of vegetal biomass is a great challenge to current research studies. This work is focused on improving the yield of enzymatic hydrolysis of wood residues by removal of lignin using a alkaline wash assisted by microwave heating. The treatments were carried out for one hour in a pressurized microwave reactor (Synthwave-Milestone). The performance of the treatments was assessed by monitoring the concentration of lignin (determined by UV absorbance at 320 nm against a calibration curve). Each experiment was carried out in duplicate. The treatment conditions were established according to an experimental matrix constructed (in Design Expert 11) after the careful selection of the most important factors that affect the lignin removal from wood residue: concentration of NaOH solution, liquid to solid ratio and temperature. A central composite design was constructed with the independent factors mentioned above. ANOVA indicated adequate fitting of the model (correlation coefficient R2=0.95). The exploration of the experimental space (figure 1) with the fitted model indicates the dominant effect of temperature as independent factor. Optimization of experimental conditions within the experimental space was carried according to the following criteria: minimization of temperature, liquid to solid ratio and NaOH concentration and maximization of the response variable, the lignin concentration. The optimal solution (141 mg lignin / g dry wood residue) proposed by the model for these optimization criteria indicates a point in the region determined by the following coordinates: 0.4M NaOH, 1070C and a ratio of liquid to solid equal to 50. Fig. 1. 3D plot of lignin responses surfaces function of the independent factors with significant effectsAcknowledgment The authors acknowledge the financial support received from Competitiveness Operational Program 2014-2020, Priority axis 1, Project No. P_36_611, MySMIS code 107066, Innovative Technologies for Materials Quality Assurance in Health, Energy and Environmental - Center for Innovative Manufacturing Solutions of Smart Biomaterials and Biomedical Surfaces – INOVABIOMED.
{"title":"OPTIMIZATION OF MICROWAVE ASSISTED DELIGNIFICATION OF WOOD RESIDUES BY SURFACE RESPONSE METHODOLOGY","authors":"A. Trifan, I. Călinescu, M. Vinatoru, A. Gavrila","doi":"10.4995/ampere2019.2019.9861","DOIUrl":"https://doi.org/10.4995/ampere2019.2019.9861","url":null,"abstract":"Efficient processing of vegetal biomass is a great challenge to current research studies. This work is focused on improving the yield of enzymatic hydrolysis of wood residues by removal of lignin using a alkaline wash assisted by microwave heating. The treatments were carried out for one hour in a pressurized microwave reactor (Synthwave-Milestone). The performance of the treatments was assessed by monitoring the concentration of lignin (determined by UV absorbance at 320 nm against a calibration curve). Each experiment was carried out in duplicate. The treatment conditions were established according to an experimental matrix constructed (in Design Expert 11) after the careful selection of the most important factors that affect the lignin removal from wood residue: concentration of NaOH solution, liquid to solid ratio and temperature. A central composite design was constructed with the independent factors mentioned above. ANOVA indicated adequate fitting of the model (correlation coefficient R2=0.95). The exploration of the experimental space (figure 1) with the fitted model indicates the dominant effect of temperature as independent factor. Optimization of experimental conditions within the experimental space was carried according to the following criteria: minimization of temperature, liquid to solid ratio and NaOH concentration and maximization of the response variable, the lignin concentration. The optimal solution (141 mg lignin / g dry wood residue) proposed by the model for these optimization criteria indicates a point in the region determined by the following coordinates: 0.4M NaOH, 1070C and a ratio of liquid to solid equal to 50. Fig. 1. 3D plot of lignin responses surfaces function of the independent factors with significant effectsAcknowledgment The authors acknowledge the financial support received from Competitiveness Operational Program 2014-2020, Priority axis 1, Project No. P_36_611, MySMIS code 107066, Innovative Technologies for Materials Quality Assurance in Health, Energy and Environmental - Center for Innovative Manufacturing Solutions of Smart Biomaterials and Biomedical Surfaces – INOVABIOMED.","PeriodicalId":277158,"journal":{"name":"Proceedings 17th International Conference on Microwave and High Frequency Heating","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116421077","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-09-09DOI: 10.4995/ampere2019.2019.9753
Jing Zhou, Yingguang Li, Di Li
For a long time, the heating pattern of the workpiece within a multimode microwave oven was considered to be highly sophisticated. As a consequence, the uneven microwave heating problem can only be partly alleviated by a random movement between the electromagnetic field and the workpiece. In this paper, we reported that the heating pattern has a specific correspondence with microwave system settings. The influence factor of the heating pattern and the corresponding mechanism were systematically studied by both theoretical analysis and experimental investigations. On this basis, a data-driven process model was established to learn the material’s dynamic temperature behaviors under different microwave system settings, and a new concept to improve the microwave heating uniformity by temperature monitoring and active compensation was proposed. The effectiveness of the method was demonstrated by a polymer composite microwave processing case study.
{"title":"A new concept to improve microwave heating uniformity through data-driven process modelling","authors":"Jing Zhou, Yingguang Li, Di Li","doi":"10.4995/ampere2019.2019.9753","DOIUrl":"https://doi.org/10.4995/ampere2019.2019.9753","url":null,"abstract":"For a long time, the heating pattern of the workpiece within a multimode microwave oven was considered to be highly sophisticated. As a consequence, the uneven microwave heating problem can only be partly alleviated by a random movement between the electromagnetic field and the workpiece. In this paper, we reported that the heating pattern has a specific correspondence with microwave system settings. The influence factor of the heating pattern and the corresponding mechanism were systematically studied by both theoretical analysis and experimental investigations. On this basis, a data-driven process model was established to learn the material’s dynamic temperature behaviors under different microwave system settings, and a new concept to improve the microwave heating uniformity by temperature monitoring and active compensation was proposed. The effectiveness of the method was demonstrated by a polymer composite microwave processing case study.","PeriodicalId":277158,"journal":{"name":"Proceedings 17th International Conference on Microwave and High Frequency Heating","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127424458","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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