Abstract The main problems of the traditional foundry dewaxing processes in fine arts workshops are the emission of gases, the loss of 80% of the wax, the high electrical consumption, and the high risks for the operators. The introduction of the microwave technology for dewaxing of ceramic shell molds allows to minimize some of these problems, although the use of electromagnetic susceptors that capture

Abstract In present studies, dielectric properties of eggshell powder were determined at microwave frequencies 2.45 and 5.8 GHz by varying temperature and moisture content in the range 15–75 °C and 0.5–8% (wet-basis) respectively, using cavity perturbation technique. Values of dielectric constant (ε′) and loss factor (ε″) increase with temperature and moisture content at both of these frequencies but

Abstract This study aims to analyze the patch antenna for moisture content measurement of made tea. The patch antenna-based system uses an air gap between the ground plane and an electrically conductive patch. The tea sample is contained in the air gap. The patch antenna design has a resonance frequency of 5 GHz. The resonance frequency and S11 parameters are measured for tea samples in the moisture

Abstract Dielectric behavior of soil has utmost applications in microwave remote sensing and soil treatment. In the present study, the soil's dielectric properties (Ɛ' and Ɛ") were measured using the vector network analyzer and an open-ended coaxial probe (85070E, Agilent Technologies) in the region of 0.2 to 14 GHz. The observed results showed that Ɛ' and Ɛ" strongly depend on frequency, texture,

Abstract In this study, a self-sensing smart structure was developed with a novel approach. Electromagnetic wave based self-sensing structure designed by sending waves to the reinforced concrete structure through the reinforcement by using a coaxial cable. EM measurements were based on estimating the reflected EM waves through the reinforced concrete. Correlations between reflected EM wave, damage

(2022). Editor's message: sufficient details in a manuscript, originality, and similarity score. Journal of Microwave Power and Electromagnetic Energy: Vol. 56, No. 2, pp. 69-70.

Abstract The present study was conducted to compare the effect of changing the spatial distance and time radio frequency (RF) radiation from mobile phone in standby mode on the structure and function of testicles. NMRI mice were randomly divided into three groups. The first group was the control and the second group (exposed group) was divided into four subgroups: groups A (A1 and A2) and groups B

Abstract It seems possible that Solid-State Radio Frequency (RF) transistors will one day replace magnetrons in consumer microwave ovens. These new ovens have the potential to be smaller and more energy efficient. Because they are closed loop systems, they can precisely cook food in ways that consumers have not seen before. This review outlines the basics of Solid-State RF systems and the consumer

Abstract Non-uniform heating is a significant challenge in radiofrequency (RF) heating of low moisture foods. Previous experiments showed that the immersion of fluids (air, deionized water, and soybean oil) changed the RF heating uniformity and rate of cornflour. However, the behind mechanism is not well understood. This study developed a finite-element-based model that incorporated quasi-static electromagnetics

Abstract This study investigated the comparative effects of conventional hot-air oven heating (CHO), microwave heating (MW) and sealing effect on the nutritive value of lucerne hay. Equivalent energy (125 J.g−1) was applied with a 1.1 kW of MW oven for 60 seconds (s) or a 3.06 kW CHO oven for 350 s. The required equivalent energy level was measured based on a preliminary calibration trial. Two heating

Abstract To effectively separate the valuable minerals in ludwigite, this study investigated the mineralogy of ore, particle-size distribution and mineral liberation characteristics. Most of the magnetite was intergrown with ascharite and serpentine. Nearly half of the serpentine existed in a dense, massive body. Most of the ascharite was encased in magnetite, and a small amount was embedded in the

(2022). Editor’s message: the solid-state applications era. Journal of Microwave Power and Electromagnetic Energy: Vol. 56, No. 1, pp. 1-2.

Abstract An investigation of sterilization by a low-temperature microwave-generated atmospheric pressure plasma jet (MAPPJ) is presented. Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), and yeast Saccharomyces species (Saccharomyces sp.) at 1.0 × 103 and 1.0 × 104 cfu/mL dilutions are investigated and fungi tested experimentally. The MAPPJ is generated by several watt continuous-wave

Abstract The aim of present work was mainly to study the influence of blanching-freezing pre-treatment on moisture removal characteristics of potato during microwave drying process. The influence of microwave power and the samples thickness was also assessed. For this purpose, microwave powers of 100, 350 and 550 W were practiced to dry discoid shape samples of fresh and blanched-frozen potatoes with

Abstract A concept for a millimetre-wave (MMW) heat exchanger (HX) featuring AlN:Mo ceramic composite structures as electromagnetic absorbing elements (susceptors) has been recently introduced as a receiving device in power beaming applications. Earlier computational studies of electromagnetic and thermal processes have shown reasonable energy efficiency and exceptional uniformity of MMW-induced temperature

Abstract This article deals with the investigations on mullite ceramics formation from Kyanite sample- an alumino-silicate mineral with microwave heating. In the present investigation kyanite was heated in microwave sintering furnace with calcined alumina, silicon carbide, zirconium dioxide and binder for mullite formation as well as for the preparation of zirconia toughened mullite product. The results

(2021). Editor message: farewell to our friend Bob Schiffmann. Journal of Microwave Power and Electromagnetic Energy: Vol. 55, No. 4, pp. 271-272.

Abstract Dielectric properties of any particular material will determine the level of microwave (MW) heating. Therefore, measurement of the dielectric properties of MW treatment subject materials is necessary. This study investigated the dielectric properties of six roughages and three concentrate animal feeds across the microwave frequency range of 1 × 109 to 5 × 109 Hz. Six treatment groups, named

Abstract This study investigates the application of artificial neural networks to determine the complex dielectric material properties derived from experimental VNA scattering parameter measurements. The study utilizes a finite element approach to synthetically generate data to train the neural network. The neural network was trained using a supervised learning approach and validated using experimental

Abstract Considering the importance of the embryonic stage, we investigated the brain and serum ADA of offspring chronically exposed to low and high frequency electromagnetic field (EMF-LF/HF) during their embryonic period. Male and female rats were randomly selected for mating. After mating, the females were divided into four groups. The first group was exposed to extremely EMF-LF (50 Hz) through

Abstract As a clean energy, microwaves have been widely used in thermal engineering. However, in the traditional microwave heating process, it is difficult to obtain high heating efficiency and uniformity. In this paper, a novel multi-port sweep frequency heating method is proposed to solve this problem. Multi-physics modelling and experiment are carried out to study the mechanism, efficiency, and

Abstract Foreign-material content determination in uncleaned peanuts based on dielectric properties and bulk density measurements by microwave techniques is presented in this paper. A microwave free-space transmission technique was used at 10 GHz. Two measurement systems for measuring the dielectric properties of cleaned unshelled peanuts (nine-peanut pods) and uncleaned unshelled peanuts placed in

(2021). Editor’s message: cooling evolution for validating microwave heating models. Journal of Microwave Power and Electromagnetic Energy: Vol. 55, No. 3, pp. 173-174.

Abstract In this study, sour cherry nectar and apple juice were concentrated using thermal concentration (75, 80, and 85 °C), and intermittent microwave concentration (180, 300, and 450 W) under vacuum condition (at 250 mbar). Thirteen different mathematical models were used to describe the concentration kinetics of the samples. The Midilli model exhibited the best fit to all experimental data (R2

Abstract The common practice of applying reflection loss to material is incorrect as it can only be applied to film. Also the dominant theory of impedance matching should be replaced by wave cancellation theory. Here, we show that experimental data obtained from microwave absorption by the film of the titled composite can be successfully analyzed theoretically from our new theories. Formulae for the

Abstract In this study, the drying kinetics and quality characteristics of microwave-assisted hot air dried beef chips were investigated. For this purpose, beef slices were treated with spice mixture (4 g/100 g beef) and then dried with 2 different air temperature (60 and 70 °C) and 3 different microwave power (0, 90 and 180 W at fixed product weight). Drying process was terminated when moisture content

Abstract The main aim of the present investigation is to develop and synthesis the precious nano-metals such as nano gold and its by product components such as nano copper, nano silver etc. The investigations were basically consisting of two level environmental friendly process i.e., recovering of the gold from discarded E-waste components and secondly with the proper reaction after boiling. The precious

Abstract The work attempts to investigate the dielectric properties and microwave drying characteristics of Yunnan lignite, so as to upgrade it. The effect of drying temperature, moisture content and microwave heating frequency on dielectric properties was measured using resonant cavity method. Results indicate that both the values of ε′ and ε″ presented two stage at the investigated temperatures.

(2021). Editor’s message: Substance of non-communication applications in JMPEE. Journal of Microwave Power and Electromagnetic Energy: Vol. 55, No. 2, pp. 91-92.

Abstract To effectively separate and recover the valuable elements iron and boron from ludwigite, this study investigated the magnetic properties and the magnetic separation efficiency. And the reactivity of boron component in the B-bearing tailing was studied. The results indicated that the saturation magnetization of ore samples was increased with the increase of microwave power and heating time

Abstract We present a new approach to the study of microwave efficiency (MW) and microwave susceptors in the process of obtaining high quality nanopowders. Susceptors accelerate the processing of various poorly absorbent materials in the microwave field, reduce processing time and energy consumption. We calculated the electric field by a three-dimensional modelling of a microwave applicator designed

Abstract This article proposed a new solution to do the plasma cleaning under low pressure based on a domestic microwave oven. A conical bottle was placed in the oven according to the electric field distribution calculated by finite element method and Helmholtz equation. A vacuum pump was employed to make a low pressure environment in the bottle to generate plasma. Experiments demonstrated that discharges

Abstract This study discusses development of a microwave-heated thin-panel metamaterial absorber (MA) for application in aircraft deicing. The base of the MA was selected to be high-silica glass cloth reinforced polyimide (GCRP), manufactured through the autoclave process. The material’s surfaces were sprayed with metal powder as per the absorber design. In simulation with an optimized parameter set

Abstract Triode-based circuits are still the less expensive and more reliable high power sources for industrial applications between 13.56 and 40.68 Mhz. Among them, self-excited oscillators feature the lower cost but with a frequency stability preventing them to address all ISM frequencies and applications. This article demonstrates the possibility to model numerically self-excited oscillators with

(2021). Editor’s message: Microwave imaging advances. Journal of Microwave Power and Electromagnetic Energy: Vol. 55, No. 1, pp. 1-2.

Abstract To effectively separate the valuable minerals in ludwigite, this study investigated the grinding fineness behaviour and liberation characteristics. The results indicated that the particle yield of −75 μm with a microwave power of 4 kW for 40 s was increased by 18.22% in comparison to that of raw ore. The D(50) and D(90) raw-ore grinding products reached 53.52 and 215.16 μm, both of which were

Abstract Non-uniform heating has been a challenging problem in microwave heating due to ‘standing wave pattern’ and ‘thermal runaway’ problems. Cycled microwave heating was used to improve microwave heating uniformity of frozen products, while a relatively new approach of inverter heating was claimed to help preserve food quality during thawing/heating. In this study, finite-element-method-based coupled

Abstract The dielectric properties and electromagnetic wave absorbing performance of granular polysilicon have important influences on microwave smelting efficiency. In this study, the dielectric parameters (dielectric constant, dielectric loss factor and loss tangent) of granular polysilicon were measured from room temperature (25 °C) to 800 °C at 2450 MHz by using the cylindrical cavity perturbation

Abstract Developing a mathematical model for the dielectric properties of water over a wide range of frequencies helps design, develop, model and optimize processes involving the interaction of electromagnetic waves with water containing materials. Based on large data sets (1744 published dielectric measurements) from literature and significant extensions to mathematical models, which have also been

Abstract To effectively separate the valuable minerals in ludwigite, this study investigated the grinding fineness behaviour and liberation characteristics. The results indicated that the particle yield of −75 μm with a microwave power of 4 kW for 40 s was increased by 18.22% in comparison to that of raw ore. The D(50) and D(90) raw-ore grinding products reached 53.52 and 215.16 μm, both of which were

Abstract The dielectric properties and electromagnetic wave absorbing performance of granular polysilicon have important influences on microwave smelting efficiency. In this study, the dielectric parameters (dielectric constant, dielectric loss factor and loss tangent) of granular polysilicon were measured from room temperature (25 °C) to 800 °C at 2450 MHz by using the cylindrical cavity perturbation

Many simulations employed in microwave heating simplify the geometric model of the microwave cavity to reduce the complexity of the model. Some detailed design features of the cavity, such as magne...

Both microorganisms and viruses are germs; the difference is that the first ones are alive while the viruses are a sort of capsules with genetic material that reproduce themselves by replication in...

Abstract Three-stub waveguides are common impedance matching devices which are essential for a wide range of high-power microwave applications. Based on equivalent circuit analysis method, this article presents a novel matching algorithm which can be applied for three-stub tuners to implement continuous, automatic and real-time impedance matching. Equivalent model of a stub waveguide is firstly established

Abstract In the present work, microwave energy was used for casting Al 7039 alloy at 2.45 GHz in the ambient cavity environment. Effects of input power and insulation of the mould assembly during irradiation on charge melting and mould preheating were studied. Five different casts were produced at 1000 W, 1200 W, 1400 W, 1400 W with an insulated pouring basin and 1400 W with insulated mould assembly

Abstract Dielectric properties of a set of glasses having the composition (70-x)%V2O5 - x%ZnO − 10%SrO − 20%FeO is studied in terms of their permittivity and electric modulus. The dielectric data are collected at the frequencies 120, 103, 104 and 105 Hz and in the temperature range 300 − 523 K. The electric moduli are treated with different theoretical models. Good fitting to the experimental data

Abstract The complex relative permittivity study of samples of liberdux® syrup dissolved in distilled–deionized water is presented. It should be mentioned that excess of this syrup as pharmaceutical residual in water is considered an emerging contaminant. The study covers liberdux® concentrations from 0% v/v to 100% v/v, which were measured from 500 MHz to 20 GHz. For each sample, the parameters of

(2020). Editor’s message: a glance to virtual conferences. Journal of Microwave Power and Electromagnetic Energy: Vol. 54, No. 3, pp. 183-185.

Abstract This paper presents a stable, accurate and wideband microwave fractional order differentiator (MFOD) based on infinite impulse response filter. The fractional order differentiator (FOD) design problem is formulated in the z-domain. This formulation alliances with the transmission line elements in cascading. Real coded genetic algorithm (RCGA), particle swarm optimization (PSO) and cuckoo search

Abstract The effects of different drying methods (hot air drying (HAD), microwave drying (MD), and hot air-microwave combined drying (HAMCD) processes) on the drying characteristics, rehydration ability, colour, texture, moisture state, microstructure, and energy characteristics of tilapia fillets have been investigated. The best rehydration and recovery ratios of tilapia fillets were obtained using

Abstract In order to exploit the use of remote sensing, microwave heating/drying and water stress in the agricultural sector, it is necessary to determine the dielectric properties of plant materials (branches, leaves, roots, fruits). In this way, the yield and quality of agricultural products can be increased. In this study, dielectric parameters of the sweet cherry and sour cherry leaves are measured

Abstract In this paper, the electromagnetic shielding effectiveness results of the plain weave composite fabric and the analytical solution of metal mesh were investigated. The composite fabric made of cotton yarns twisted with 50 µm copper filaments was used in the experiment. As the fabric was weaved and stretched, it had square shaped apertures which had length of 1.2 mm. The electromagnetic shielding

Abstract Microwave-assisted hydrodistillation and conventional hydrodistillation (MAHD and HD) were used for a comparative study of extraction Callistemon citrinus Skeels leaf essential oils. The time required for a MAHD method is 75 minutes that for HD method is 3.5 hours, so MAHD requires lesser time. The increases in yield of extracted oil by MAHD (0.84%) is found compared oil extracted by HD (0

Ancient technology was aimed to manufacture tools and other devices using materials chosen due to their good structural properties. Toughness was an important criterion, but with invention of new artefacts led to greater requirements so that new materials were sought. The problem was that available materials in nature did not fulfil such needs, hence it was no longer a matter of materials choice, but

Abstract This work aims to improve the uniformity and efficiency of microwave heating. A dual-port simulation model based on the finite element method was built, and two pins were applied to the heating cavity. The impact of dual frequency and pins on the coefficient of variation (COV) and heating efficiency were investigated. The results demonstrated that the uniformity of dual-frequency heating can

Abstract Little published information exists examining the effect of heating methods on nutrient retention in single-serve frozen meals, which can have instructions for conventional and microwave ovens. In peer-reviewed references, there are no recent studies that address this question. This work compares the effect of two reheating methods on nutrient retention of a frozen single-serve meal that has

Abstract The thin layer drying of Eri silkworm pupae using microwaves combined with hot air was conducted. Several empirical models simulating thin layer drying of Eri silkworm pupae were selected and analyzed. Microwave power between 100 and 200 W and drying temperatures between 50 and 70°C were used in the study. The comparison between experimental results and those of the models indicated that the

Abstract The use of polyols as green solvents in conjunction with microwave heating (MH) has become a very attractive synthetic protocol nowadays. However, among the needs of this area, as well as any other that uses MH, figure the electromagnetic properties of the materials. In this context, the contribution of this work is provide dielectric data of three polyols: glycerol, 1,2-propanediol and 1

Abstract There are five stages in acid coagulation of milk and most studies miss out on a stage or two depending on the experiments performed. Dielectric studies of milk and various physico-chemical studies on the formation of yogurt are well studied and established. However, most of the papers deal with either a limited range of frequencies in the dielectric studies and hence are unable to reflect

(2020). Editor’s message: experiments with microwave kitchen ovens. Journal of Microwave Power and Electromagnetic Energy: Vol. 54, No. 1, pp. 1-2.