DEVICE AND METHOD FOR CONTROLLING MICROWAVE SEED TREATMENT ON A CONVEYOR BELT

2021 ◽  
pp. 59-65
Author(s):  
ALEKSANDR N. MALAKHOV ◽  
Keyword(s):  
Microwave Heating ◽  
Electromagnetic Waves ◽  
Heating Temperature ◽  
Dielectric Materials ◽  
Microwave Treatment ◽  
Conveyor Belt ◽  
Microwave Devices ◽  
Microwave Source ◽  
Processing Modes ◽  
High Yields

The sowing qualities of seeds – such as germination, germination energy, weight of 1000 seeds, etc., are the factors ensuring high yields of agricultural crops. Technological methods of seed and grain treatment with the UHF MEMF (microwave electromagnetic fi eld of ultrahigh frequency) energy involve the use of various types of microwave devices, diff ering both in operating principle and in design. In fact, the process of microwave treatment of seeds is similar to the process of heat treatment of dielectric materials. Therefore, depending on the goal of treatment, microwave devices should provide some kind of selectivity of microwave heating, a high conversion factor of microwave energy into thermal energy, uniformity of microwave treatment of the bulk of material, protection of the microwave generator and electromagnetic safety. During the microwave treatment of seeds, it is important to ensure uniform treatment of the bulk of seeds and automatically maintain optimal treatment modes (microwave heating modes). An installation design is proposed for microwave treatment of seeds. A specifi c feature of the proposed design is that seeds are processed on a moving belt under an emitter with the process control and regulation according to the speed and fi nal heating temperature. Moreover, the microwave source intensity depends on the load (a layer of seeds on the conveyor belt). The authors also propose an algorithm for the microprocessor control of the device. Thus, the proposed design of the installation for treating seeds in a layer under the emitter on a moving conveyor belt, as well as the technological algorithm for matching the microwave source with the load ensure the compliance with the processing modes in strictly specifi ed ranges of the fi nal temperature and microwave heating rate of the material, as well as protect the microwave source from refl ected electromagnetic waves.

A New Way to Uniform Microwave Treatment of Epoxy Glass

2015 ◽  
Vol 813 ◽  
pp. 265-272
Author(s):  
Wei Wei Du ◽  
Lyes Douadji ◽  
Fethi Benkhenafou ◽  
Hong He ◽  
Cheng Li
Keyword(s):  
Electromagnetic Waves ◽  
Microwave Treatment ◽  
Microwave Processing ◽  
Leaf Spring ◽  
Microwave Source ◽  
Electromagnetic Modelling ◽  
Dielectric Effect ◽  
Microwave Heat ◽  
Uniform Treatment ◽  
Microwave Process

This work is part of an ambitious project aiming to manufacture epoxy-glass leaf spring by microwave processing. Physical properties of final products to be manufactured, in particular the mechanical properties, are directly dependent on uniform repartition of microwave source heating during the treatment. The major problem in microwave processing, however, is attenuation of microwave source. We propose Dielectric Effect of Attenuation Inversion of the Electromagnetic Waves (DEAI) as a new way for uniform treatment of epoxy glassmicrowave energy. This solution utilizes dielectric properties of the mold to control the microwave heat source attenuation into the composite to be treated. Electromagnetic modelling of microwave process was carried out and validated by experimental results. The results show that microwave source heating attenuation can be controlled and inversed. We demonstrated uniform treatment on epoxy-glass parts ca. 100 cm long by means of compensation of microwave source attenuation.

scholarly journals Features of technological processing of seeds with an electromagnetic field of microwave before sowing

2021 ◽  
Vol 845 (1) ◽  
pp. 012142
Author(s):  
S V Vendin
Keyword(s):  
Microwave Heating ◽  
Crop Production ◽  
Heating Temperature ◽  
Experimental Studies ◽  
Microwave Treatment ◽  
Microwave Exposure ◽  
Soil Preparation ◽  
Technological Processing ◽  
The Impact ◽  
The Relationship

Abstract To increase the efficiency of crop production in the arsenal of the agronomic service there is a number of techniques, methods and technologies that reveal the potential of agricultural plants for all stages of production, starting with soil preparation, selection and preparation of seeds for sowing, agrotechnological measures during the growing season, harvesting technologies, storage and processing of products. The article presents the results of experimental studies on the use of the energy of ultra-high frequency electromagnetic fields for pre-sowing treatment of lupine seeds in order to increase their germination. Revealed the relationship between the parameters of microwave exposure and seed germination. The areas of modes where microwave treatment allows to increase germination, as well as areas of modes in which the impact does not reach the planned effect, or has a negative (depressing) effect, have been determined. Recommendations are given for ensuring the optimal modes of microwave processing and ensuring control of the parameters of the technological process. Based on the results obtained, it can be reliably asserted that the region of microwave treatment of lupine seeds, with a result exceeding the control values, is observed at exposure in the range from 50 to 60 s and at a specific microwave power of exposure from 1.0 to 1.17 kW/kg. The best result of an increase in germination by 1.5% was obtained at 60 s and 1.17 kW/kg. When treating seeds, it is recommended to maintain an average microwave heating rate of 0.50 °C/s until an average microwave heating temperature of 51.5 °C is reached.

Microwave Heating of Hydrated Zeolites and Application of Zeolites as a Domestic Reusable Desiccant through its Technique

2005 ◽  
Vol 23 ◽  
pp. 195-198
Author(s):  
Tatsuo Ohgushi ◽  
Mayumi Nagae
Keyword(s):  
Adsorption Capacity ◽  
Microwave Heating ◽  
Microwave Radiation ◽  
Heating Temperature ◽  
Microwave Treatment ◽  
Thermal Runaway ◽  
X Zeolite ◽  
Degradation Degree ◽  
Lower Heating

Na-X zeolite easily caused a thermal runaway by microwave radiation of 500W but Ca-X zeolite merely reached ca. 300°C. Mixtures of Ca-X and Na-X reached lower heating temperature with increasing the content of Ca-X and the heating temperature could be controlled (>300°C) by adjusting the content. Since water in X zeolite almost completely desorbs by 400°C, conditions realizing the heating temperature of ca. 400°C were studied. The mixture with the ratio of Ca-X/Na-X=0.9/0.1 was quickly heated to ca. 400°C by the radiation of 10-20 min in the 500 W power and reached the dehydration state up to >90 %. A degradation degree of adsorption capacity of the mixture for water was examined after two and three treatments with the microwave heating. The average degradation degree was 1.4 % per treatment. The properties of the zeolite desiccant with microwave treatment were compared with those of commercial CaCl2 desiccant. It was found that the zeolite desiccant is superior to the commercial desiccant and an application of zeolite to a domestic reusable desiccant, through the heating technique, is promising.

Evaluation of the accuracy of reconstruction of the electrophysical and geometric parameters of multilayer dielectric coatings by the multi-frequency radio wave method of a slow surface electromagnetic waves

2020 ◽  
pp. 51-58
Author(s):  
Aleksandr I. Kazmin ◽  
Pavel A. Fedjunin
Keyword(s):  
Radio Wave ◽  
Noise Level ◽  
Electromagnetic Waves ◽  
Dielectric Materials ◽  
Geometric Parameters ◽  
Experimental Investigations ◽  
Wave Method ◽  
Dielectric Coatings ◽  
Surface Electromagnetic Waves ◽  
Multilayer Dielectric

One of the most important diagnostic problems multilayer dielectric materials and coatings is the development of methods for quantitative interpretation of the checkout results their electrophysical and geometric parameters. The results of a study of the potential informativeness of the multi-frequency radio wave method of surface electromagnetic waves during reconstruction of the electrophysical and geometric parameters of multilayer dielectric coatings are presented. The simulation model is presented that makes it possible to evaluate of the accuracy of reconstruction of the electrophysical and geometric parameters of multilayer dielectric coatings. The model takes into account the values of the electrophysical and geometric parameters of the coating, the noise level in the measurement data and the measurement bandwidth. The results of simulation and experimental investigations of reconstruction of the structure of relative permittivitties and thicknesses of single-layer and double-layer dielectric coatings with different thicknesses, with different values of the standard deviation (RMS) of the noise level in the measured attenuation coefficients of the surface slow electromagnetic wave are presented. Coatings based on the following materials were investigated: polymethyl methacrylate, F-4D PTFE, RO3010. The accuracy of reconstruction of the electrophysical parameters of the layers decreases with an increase in the number of evaluated parameters and an increase in the noise level. The accuracy of the estimates of the electrophysical parameters of the layers also decreases with a decrease in their relative permittivity and thickness. The results of experimental studies confirm the adequacy of the developed simulation model. The presented model allows for a specific measuring complex that implements the multi-frequency radio wave method of surface electromagnetic waves, to quantify the potential possibilities for the accuracy of reconstruction of the electrophysical and geometric parameters of multilayer dielectric materials and coatings. Experimental investigations and simulation results of a multilayer dielectric coating demonstrated the theoretical capabilities gained relative error permittivity and thickness of the individual layers with relative error not greater than 10 %, with a measurement bandwidth of 1 GHz and RMS of noise level 0,003–0,004.

Hafnium(IV) Chloride Catalyzes Highly Efficient Acetalization of Carbonyl Compounds

2019 ◽  
Vol 16 (6) ◽  
pp. 913-920 ◽  
Author(s):  
Israel Bonilla-Landa ◽  
Emizael López-Hernández ◽  
Felipe Barrera-Méndez ◽  
Nadia C. Salas ◽  
José L. Olivares-Romero
Keyword(s):  
Microwave Heating ◽  
Reaction Times ◽  
Protecting Groups ◽  
Catalyst Loading ◽  
Selective Protection ◽  
Highly Efficient ◽  
Aldehydes And Ketones ◽  
High Yields ◽  
Novel Catalyst ◽  
Acid Labile

Background: Hafnium(IV) tetrachloride efficiently catalyzes the protection of a variety of aldehydes and ketones, including benzophenone, acetophenone, and cyclohexanone, to the corresponding dimethyl acetals and 1,3-dioxolanes, under microwave heating. Substrates possessing acid-labile protecting groups (TBDPS and Boc) chemoselectively generated the corresponding acetal/ketal in excellent yields. Aim and Objective: In this study. the selective protection of aldehydes and ketones using a Hafnium(IV) chloride, which is a novel catalyst, under microwave heating was observed. Hence, it is imperative to find suitable conditions to promote the protection reaction in high yields and short reaction times. This study was undertaken not only to find a novel catalyst but also to perform the reaction with substrates bearing acid-labile protecting groups, and study the more challenging ketones as benzophenone. Materials and Methods: Using a microwave synthesis reactor Monowave 400 of Anton Paar, the protection reaction was performed on a raging temperature of 100°C ±1, a pressure of 2.9 bar, and an electric power of 50 W. More than 40 substrates have been screened and protected, not only the aldehydes were protected in high yields but also the more challenging ketones such as benzophenone were protected. All the products were purified by simple flash column chromatography, using silica gel and hexanes/ethyl acetate (90:10) as eluents. Finally, the protected substrates were characterized by NMR 1H, 13C and APCI-HRMS-QTOF. Results: Preliminary screening allowed us to find that 5 mol % of the catalyst is enough to furnish the protected aldehyde or ketone in up to 99% yield. Also it was found that substrates with a variety of substitutions on the aromatic ring (aldehyde or ketone), that include electron-withdrawing and electrondonating group, can be protected using this methodology in high yields. The more challenging cyclic ketones were also protected in up to 86% yield. It was found that trimethyl orthoformate is a very good additive to obtain the protected acetophenone. Finally, the protection of aldehydes with sensitive functional groups was performed. Indeed, it was found that substrates bearing acid labile groups such as Boc and TBDPS, chemoselectively generated the corresponding acetal/ketal compound while keeping the protective groups intact in up to 73% yield. Conclusion: Hafnium(IV) chloride as a catalyst provides a simple, highly efficient, and general chemoselective methodology for the protection of a variety of structurally diverse aldehydes and ketones. The major advantages offered by this method are: high yields, low catalyst loading, air-stability, and non-toxicity.

Electromagnetic waves transmission performance of alumina refractory ceramics in 2.45 GHz microwave heating

2019 ◽  
Vol 45 (17) ◽  
pp. 23493-23500 ◽  
Author(s):  
Xiaobiao Shang ◽  
Di Zhai ◽  
Fucheng Zhang ◽  
Cong Wei ◽  
Junruo Chen ◽  
...  
Keyword(s):  
Microwave Heating ◽  
Electromagnetic Waves ◽  
Transmission Performance ◽  
Alumina Refractory ◽  
Refractory Ceramics

scholarly journals Microwave-induced heating behavior of Y-TZP ceramics under multiphysics system

2020 ◽  
Vol 9 (1) ◽  
pp. 119-130
Author(s):  
Kaihui Cui ◽  
Tianqi Liao ◽  
Chen Qiu ◽  
Hua Chen ◽  
Junwen Zhou
Keyword(s):  
Numerical Model ◽  
Microwave Heating ◽  
Three Dimensional ◽  
Heating System ◽  
Dielectric Materials ◽  
Microwave Cavity ◽  
Heating Process ◽  
Highly Sensitive ◽  
Dimensional Distribution ◽  
Heating Behavior

AbstractThis paper aims to investigate the heating behaviors of Y-TZP arrays under microwave irradiation. In this study, a three-dimensional numerical model of the microwave heating system was developed by COMSOL Multiphysics software. The numerical model was verified by microwave heating experiment, and the average root means square errors (RMSE) between the simulation and experimental data also confirmed the reliability of the model. The varying position and arrays of materials were applied to predict and visualize the three-dimensional distribution of the electromagnetic field and temperature during the microwave heating process. The results show that the temperature field distribution in microwave cavity was highly sensitive to the dielectric materials, the arrangement of the Y-TZP array interfered with the distribution of standing waves. The results can serve as references for the study to design and optimize the ceramic’s application in terms of microwave heating.

scholarly journals Microwave treatment of rice

2013 ◽  
Vol 19 (No. 2) ◽  
pp. 62-66 ◽  
Author(s):  
J. Kaasová ◽  
P. Kadlec ◽  
Z. Bubník ◽  
V. Pour
Keyword(s):  
Microwave Heating ◽  
Starch Content ◽  
Initial Moisture Content ◽  
Microwave Treatment ◽  
Drying Time ◽  
Treated Sample ◽  
System Temperature ◽  
Rice Drying ◽  
The Stability ◽  
Total Starch

The effect of microwave treatment on wet rice was studied. Power output used was 90, 160, 350 or 500 W; final heating temperatures were 40, 60 and 80°C; initial moisture content of rice was 11, 21 or 30%. Temperature of treated sample during microwave heating was measured by means of NoEMI fiber-optic temperature system. Temperature of rice gelatinization, expressed as alkali spreading values and total starch content, was used to evaluate the influence of microwave heating on physicochemical properties of rice. Drying time reduction and the stability of total starch content during microwave treatment of rice makes it possible to recommend the combination of microwave and conventional rice drying for further use.

Electrochemically Prepared Pore Arrays for Photonic-Crystal Applications

MRS Bulletin ◽  
2001 ◽  
Vol 26 (8) ◽  
pp. 623-626 ◽  
Author(s):  
R.B. Wehrspohn ◽  
J. Schilling
Keyword(s):  
Photonic Crystal ◽  
Photonic Crystals ◽  
Electromagnetic Waves ◽  
Porous Alumina ◽  
Dielectric Materials ◽  
Dielectric Medium ◽  
Geometrical Parameters ◽  
Quarter Wavelength ◽  
Physically Based ◽  
1D Photonic Crystal

In the last few years, photonic crystals have gained considerable interest due to their ability to “mold the flow of light.” Photonic crystals are physically based on Bragg reflections of electromagnetic waves. In simple terms, a one-dimensional (1D) photonic crystal is a periodic stack of thin dielectric films with two different refractive indices, n1 and n2. The two important geometrical parameters determining the wavelength of the photonic bandgap are the lattice constant, a = d1(n1) + d2(n2), and the ratio of d1 to a (where d1 is the thickness of the layer with refractive index n1, and d2 is the thickness of layer n2). For a simple quarter-wavelength stack, the center wavelength λ of the 1D photonic crystal would be simply λ = 2n1d1 + 2n2d2. In the case of 2D photonic crystals, the concept is extended to either airholes in a dielectric medium or dielectric rods in air. Therefore, ordered porous dielectric materials like porous silicon or porous alumina are intrinsically 2D photonic crystals.

PHOTONIC GAPS IN PERIODIC DIELECTRIC STRUCTURES

1992 ◽  
Vol 06 (03) ◽  
pp. 139-144 ◽  
Author(s):  
C.T. CHAN ◽  
K.M. HO ◽  
C.M. SOUKOULIS
Keyword(s):  
Plane Wave ◽  
Electromagnetic Waves ◽  
Expansion Method ◽  
Dielectric Materials ◽  
Band Gaps ◽  
Plane Wave Expansion ◽  
Photonic Band Gaps ◽  
Plane Wave Expansion Method ◽  
Dielectric Structures ◽  
Photonic Band

Using a plane wave expansion method, we solved the Maxwell’s equations for the propagation of electromagnetic waves inside periodic dielectric materials, and found the existence of photonic band gaps in several classes of periodic dielectric structures.

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