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

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 HAMCD (58

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 algorithm

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 (0.6%). Essential

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 effectiveness

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 by waveguide

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 1,3-propanediol

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 all the

(2020). Editor’s message: microwave processing of modern materials. Journal of Microwave Power and Electromagnetic Energy: Vol. 54, No. 2, pp. 81-82.

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

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 Page’s

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 be improved

(2019). Editor’s message: Communication applications and perception of microwave effect. Journal of Microwave Power and Electromagnetic Energy: Vol. 53, No. 4, pp. 213-214.

This research studied the effects of power level and aspect ratio by numerical and experimental analysis in the microwave heating process. The sample was congee frozen rice. A three-dimensional model developed to solve Maxwell’s equations and Fourier’s heat equations using the finite element method in COMSOL Multiphysics software. The simulated temperature results were validated experimental results

Squalene is a triterpene of pharmaceutical interest, due to its antioxidant and anticancer properties. Amaranth oil is a source of plant origin with high squalene content which is extracted by conventional methods that involve high cost, time-consuming and create large amounts of waste by-products or CO2 emissions. In this study, the microwave-assisted extraction (MAE) was used to obtain amaranth oil

Continuous microwave heating has the potential to revolutionize processing operations in which high energy densities per unit volume are required. The adoption of microwave heating for large scale commercial application has been hampered by a lack of reliable information on the temperature distribution during heating of pumpable fluids. This study represents an initial attempt to design a system that

This article is related to the proposed hypothesis and experimental data regarding the ability of defined polar polymer compound (MRET polymer) applied to RF phones to increase the dielectric permittivity of water based solutions and to reduce the SAR (Specific Absorption Rate) values inside the "phantom head" filled with the jelly simulating muscle and brain tissues. Due to the high organizational

Cyanine dyes are an interesting class of near infrared (NIR) dyes that have captured the interest of the scientific community. The NIR cyanine dye of interest, heptamethine cyanine dye NIR-1, exhibits characteristics that satisfy the qualifications as an acceptor in a Fluorescence Resonance Energy Transfer (FRET) biosensor [Wher, 1976]. Applications of FRET systems include structure determination and

This work examines the role of 672 nm optical illumination on the diffusion and activation of B in Si as a function of various factors. The factors studied include length of anneal, maximum temperature of anneal, type of co-implanted and pre-amorphizing species and ambient oxygen concentration. The anneal conditions fell into one of three categories: (1) high-temperature (> 900 degrees C) spike and

Experiments were conducted to compare the annealing of nano-porous aluminum oxide membranes by 2.45 GHz microwave radiation and by conventional (resistive element) furnace heating. The starting material was Al2O3 membranes that were 60 microm thick, 13 mm in diameter, and containing pores of approximately 200 nm diameter. Changes in the porosity and morphology were recorded from digital processing

Microwave radiation of 2450 MHz frequency was used to irradiate sandy loam soil placed in 12 cm high and 10 cm dia columns as a function of exposure times of 30, 45, 60, and 120 s. This was done to evaluate the effect of radiation on the highest soil temperature attained and subsequent temperature patterns in relation to time. Soil columns were packed to a field bulk density of approximately 1.4 g/cm3

In this paper, external electric field values that are derived from the largest peak average 10 g SAR (Specific Absorption Rate) results in a realistic human head model are compared with current IEEE and ICNIRP reference levels. The head is illuminated by a plane wave source at seven different frequencies ranging from 500 MHz to 2500 MHz, with five different incident directions and three polarizations

Clear evidence for the microwave effect has been observed during experiments in which a variety of materials have been heated using experimental systems that allowed both conventional and conventional-microwave hybrid heating. A hybrid single mode cavity has been used to investigate the microwave effect during phase changes in silver iodide, barium titanate and benzil, whilst a hybrid multimode cavity

Experiments and computer simulations were conducted to systematically investigate the influence of mashed potato dielectric properties and circulating water electric conductivity on electromagnetic field distribution, heating rate, and heating pattern in packaged food during radio frequency (RF) heating processes in a 6 kW, 27 MHz laboratory scale RF heating system. Both experimental and simulation

This paper presents the design and realization of a microwave applicator at 2.45 GHz for the synthesis of gold nanoparticles. The particles are dissolved in N,N-dimethylformamide (DMF). The heating rate is approximately 8 K/s to achieve a short crystallization time. For a proper applicator design it is necessary to know the dielectric properties of DMF. Therefore, the complex permittivity of DMF at

Dehydration of inorganic crystallohydrates (Fe2F x 7.1H2O, FeF3 x 3.82O, CoF2 x 4H2O, and NiF2 x 4.4H2O) in the conditions of microwave treatment (MWT) is studied. It is shown that in all cases the MWT changes the defectness of crystals, as well as their thermal stability. The dehydration schemes for the compounds above are presented.

Silicon nitride requires the use of susceptive additives for microwave liquid phase sintering due to the material's low dielectric loss. In this article, we report the effect of complex dielectric properties of two compositions of sintering aids on 2.45 GHz microwave sintered Si3N4 with respect to power absorption, temperature distribution and densification behavior. The temperature dependent dielectric

A continuous microwave heating system was tested for its effectiveness at removing potentially invasive organisms during deballasting operations. Four different organisms, namely Nannochloropsis oculata (microalgae), Artemia nauplii, Artemia adults and Crassosstrea virginica (oyster larvae) normally found in ballast water were investigated in a controlled study to quantify their survival after continuous

The electromagnetic and thermal analyses of a mode-stirred chamber designed for the heat treatment of antique and precious books are proposed. In particular, the electromagnetic and thermal perturbations due to the presence of metallic insets inside the treated material (paper) are investigated. The temperature measurement results obtained by thermography and by temperature fiber-optic sensor are also

The palm oil mills extraction process requires the separation of oil-water-sludge emulsions. For this purpose, the use of sedimentation and/or centrifugation techniques have been required until now. However, significant losses persist in different process flows and new methods are needed to further decrease them, such as methods based on electromagnetic waves application. In the study, emulsions obtained

Ballast water presents an important vector for introduction of aquatic invasive species in the coastal waters around the world. Currently there are no established technologies proven to completely eliminate this problem due to the particularities of the ballasting and de-ballasting operations (extremely large volumes of water, efficiency at destroying macro and micro organisms, environmental issues

A practical method for measuring the complex relative permittivity of epoxy resins and other viscous liquids over a wide temperature range in S-band is presented. The method involves inserting a hot glass tube, filled with the liquid-under-test (LUT), into a length of WR-340 rectangular waveguide connected between two ports of a Vector Network Analyzer, which measures the reflection and transmission

The occurrence and extent of selective dielectric heating with microwaves (MW) and radio waves (RW) was studied with a variety of model systems using temperature-programmed desorption (TPD). Over a wide pressure and temperature range, selectivity effects were neither found for polar adsorbates (compared to non-polar compounds) nor expressed by an overheating of metal clusters supported on a nearly

The structure of the emission spectrum in the near-UV range (240 nm-310 nm) changes drastically from the continuous spectrum to a discrete line spectrum with increasing sample temperature during the carbothermic reduction of magnetite in a 2.45 GHz microwave multimode furnace. The continuous spectrum can be assigned as a cathodoluminescence of magnetite. The dynamic evolution of the spectrum from continuous

Through the use of molecular dynamics simulations, we have studied the enhanced heating of salty ice and water by the electric field of applied microwaves at 2.5 GHz, and in the range of 2.5-10 GHz for the frequency dependence. We show that water molecules in salty ice are allowed to rotate in response to the microwave electric field to the extent comparable to those in pure water because the molecules

A novel microwave (MW) injector at 2.45 GHz for resin infiltration has been developed at the Institute for Pulsed Power and Microwave Technology (IHM), Research Center Karlsruhe (FZK), Germany. Resin injection is an essential step in the production of carbon fibre reinforced plastics (CFRP) for aerospace applications. A compact, low-cost and automated MW injector provides an efficient and safe energy

Selective dielectric heating using the influence of a coupling medium such as water can lead to the formation of combined temperature-mass transport pulses moving through a packed bed. Depending on the dielectric and sorption properties of the material, these so-called thermo-chromatographic pulses (TCP) can cause large temperature differences between the starting temperature and the peak temperature

Microwave energy is an alternative energy source that is receiving a considerable amount of attention from researchers for a wide spectrum of applications. The fundamentally different method of transferring energy from the source to the sample is the main benefit of utilizing microwave energy; by directly delivering energy to microwave-absorbing materials, conventional issues such as long heating periods

The food industry is keen to have new techniques that improve the safety and/or shelf life of food products without the use of preservatives. There is considerable interest in developing UV light and ozone (O3) treatments to enhance shelf life. A microwave radiation device that is a novel source of germicidal UV and O3 suitable for the food industry has been developed, which offers speed, cost and

Saskatoon berry (Amelanchier alnifolia) is a high moisture content fruit crop, harvested at 75-80% moisture content (w.b.) and dried to lower moisture contents for a safe, extended shelf-life and for further usage in food applications. Saskatoon berries were dried from an initial moisture content of 75.5% to around 25% (w.b.) using microwave-vacuum drying. In this study, saskatoon berries were dried

The authors discuss some methods of permittivity and permeability measurements which use a single rectangular sample of material placed in a waveguide. They discuss the accuracy to which the vector network analyzer (VNA) is calibrated, and if the least squares treatment of the collected data is appropriate, and how it can best be done for obtaining a robust determination of the results.

The objective of the research reported here is to investigate the influence of radio-frequency electric fields of high strength on insect mortality. The experiments were accomplished at the frequencies 47.5, 900 and 2,450 MHz for the pulse modulated radiation treatment and the continuous wave RF radiation. Two types of systems, which are the coaxial irradiation chamber and the irradiation chamber with

Millimeter-wave components were re-examined for high power (Mega-Watt) and steady-state (greater than one hour) operation. Some millimeter-wave components, including waveguide joints, vacuum pumping sections, power monitors, sliding waveguides, and injection windows, have been improved for high power CW (Continuous Waves) transmission. To improve transmission efficiency, information about the wave

For aviation, a suitable alternative for currently used in-flight anti-/de-icing technologies for today's aircrafts with metal structures and future aircrafts with replaced composite structures is necessary. Intense investigations performed at FZK have been together in collaboration with aircraft manufacturers to design and develop a new avionic microwave technology for monolithic composite structures

In the present study we investigate the stability of Cu50Zr45Al5 and Ni59Ti16Zr20Sn5 glassy powders and the formation of the bulk metallic glassy samples by microwave heating in a single mode cavity (915 MHz) in the alternating magnetic field maximum. Metallic glasses exhibit low viscosity at temperatures close to the glass-transition which allows for the processing of glassy powders. Microwave heating

In the course of experiments to perform deprotonation and carbonization of doped polyaniline (PANI) nanotubes (NTs) by irradiating directly 2.45 GHz microwave (MW) in our microwave heating system (MWHS), we have discovered that the PANI-NTs self heat by absorbing the MW but the temperature of the PANI-NTs stops rising around 300 degrees C in spite of the heightened MW power Furthermore, we have found

In order to discuss the temperature distributions due to microwave (MW) selective heating of multi-phase solids, numerical analysis was conducted. The simulation was performed assuming the dielectric heating mechanism in a dual phase solid in which one phase has much larger permittivity (loss factor) than the other In addition, an electric (E-) field inside the solid was assumed to be homogeneous,

In this study, nonconductor (PZT), semiconductor (Si) and conductor (Pt/Ti) whose permittivity and permeability are distinctive are prepared into various multilayered structures for exploring the heating behavior of microwave (2.45 Hz) in a single-mode cavity. The heating efficiency of the semiconductor and conductor was much higher at the maximum of H field than that of E field. At the H maximum,

In the present study, we prepared Ni59.35Nb34.45Sn6.2 metallic glassy alloy powder by an argon gas atomization process. Microwave (MW)-induced heating and sintering was carried out by a single-mode 2.45 GHz MW applicator in the separated magnetic field or electric field using the obtained glassy powders. The structure and thermal stability of the sintered glassy alloy specimens were investigated.

Microwave processing is emerging as an innovative and highly effective material processing method offering many advantages over conventional methods, especially for sintering applications. It is recognized for its various advantages, such as: time and energy saving, rapid heating rates, considerably reduced processing cycle time and temperature, fine microstructures and improved mechanical properties

In recent years, microwave processing of metal/alloy powders have gained considerable potential in the field of material synthesis. Microwave heating is recognized for its various advantages such as: time and energy saving, rapid heating rates, considerably reduced processing cycle time and temperature, fine microstructures and improved mechanical properties, better product performance, etc. Microwave

A new radiation biotechnology for the acquirement of a commercial vaccine, designed for prophylaxis of ruminant infectious pododermatitis (IP), produced by gram negative bacteria Fusobacterium necrophorum (F.n.), is presented. Two different processes for preparing F.n. vaccine are used: a) the inactivation of F.n. bacteria exotoxins by microwave (MW) or/and electron beams (EB) irradiation; b) the isolation

Measured influence of microwave heating on time dependencies of component temperatures for two immiscible liquids in a mixture shows differences for polar (water) and non-polar (cyclohexane or carbon tetrachloride) liquids. The rate of increase for the temperature of water with time of microwave heating is larger than other liquids in the mixture (maximum rate of temperature growth for water is 8 times

Microwave heating and conventional heating were used in the drying process of white phosphates and the pyrolysis of black phosphate. Microwave drying has been found to present faster kinetics, and the reaction mechanism is controlled by interfacial progression with a cylindrical symmetry for low powers and by diffusion for high microwave powers. Infrared thermography analysis shows that the heating

Electromagnetic field interaction with biological tissues and their applications in cancer treatment research has become of growing interest. This paper describes the possibility of using a slot-line type applicator for microwave hyperthermia treatment in oncology. What we aim to show in this paper is that this type of applicator is particularly suitable for the treatment of superficial cancers with

In this paper the design of a handheld light applicator for microwave heating is presented. The applicator is made of an array of resonant longitudinal slots cut on a broad wall of a rectangular waveguide, and it is covered by a cylindrical lens made of Plexiglas with a permittivity of 2.53. The geometrical optics approach is used as initial approximation to establish the lens profile. It allows for

The desalted cod industry needs a suitable and reliable control system to check the desalting point of cod in order to provide a safe and high-quality product. The growth of the industries that are interested in a non-contacting, real-time control, encourages the development of new methods based on low-power radiation, such as dielectric spectroscopy. These techniques use the modification of wave parameters

Flax fiber is one of the important bast fiber available in North America which has low density and good mechanical properties for reinforcing various polymers to develop industrial biocomposite. But the hydrophilic nature of the fiber leads to poor adhesion between the fiber and the polymer matrices which, in turn, leads to poor dimensional stability. To enhance the adhesion between polymer matrix

This paper presents comparative results obtained by conventional vulcanization with benzoyl peroxide (CV-BP), separate electron beam vulcanization (EB-V) and simultaneous electron beam and microwave vulcanization (EB+MW-V) applied to two kind of rubber samples: EVA (ethylene vinyl acetate) rubber-sample (EVA-sample) and EPDM (ethylene-propylene terpolymer) rubber-sample (EPDM-sample). The EVA-samples

The paper presents two microwave (MW) exposure systems (MWESs) that permit observations and measurements on cell cultures during their exposure to MW of 2.45 GHz: MWES-1 and MWES-2. MWES-1 is designed for the measurement of the cell membrane fluorescence anisotropies (MFA) simultaneously with MW exposure. MWES-2 is designed for the cells culture exploration under an inverted microscope before, during