Effect Of Microwave Irradiation Research Articles

Experimental Study on Sucrose Losses of Sugarcane by 2450 MHz Microwave Technology

Sugarcane is one of the essential raw materials for sugar production worldwide. From a present perspective, extending the storage time of sugarcane after harvest is a crucial step toward increasing sugar production. Particularly, sugarcane harvested by sugarcane harvesters is more susceptible to biological damage due to the increased number of wounds created during harvesting. Once harvested, the most effective way to reduce bio-injury is to deliver sugarcane to the factory as soon as possible. In recent years, microwave radiation has been increasingly used in food products to reduce biological contamination. The present study examines the effect of microwave irradiation on the sucrose loss that occurs in post-harvest sugarcane. A microwave was employed for different time intervals, particularly from 5 to 9 s at a 2450 MHz frequency and 5100 W power. The results reveal that microwave radiation can effectively kill microorganisms in sugarcane wounds in a very short time. With a microwave irradiation time of 6 s, a microbial disinfection efficiency of 91.2% was achieved. The maximum temperature in the billets at that time was only 35.1 °C. Microwave radiation reduced the sucrose loss rate due to a significant decrease in the number of microflora during the 48 h period. As a result, the storage time of harvested sugarcane was prolonged, leading to improved economic benefits in sugar extraction.

Effect of 915‐MHz low‐temperature microwave irradiation on the molecular structure of coking coal

AbstractThe effect of microwave irradiation on the coking‐coal structure is important to study at the molecular scale to improve the quality of coking coal and optimize the coal‐blending technology for low‐quality coal. Through the characterization of coal structure by Fourier transform infrared spectrometer (FTIR), carbon‐13 nuclear magnetic resonance (13C‐NMR), and X‐ray photoelectron spectroscopy (XPS), the macromolecular structure unit model of coal before and after 915‐MHz microwave irradiation were constructed. A small number of alkyl side chains and cycloalkanes were broken, aromatic structures underwent condensation, and the aromatization of coal structure was increased after 915‐MHz microwave irradiation within 100–150°C. The content of hydroxyl self‐conjugated hydrogen bonds was increased, and the coal had more conjugated structures. Some phenolic hydroxyl groups and other functional groups were oxidized. The content of protonated pyridine and nitrogen oxides were increased, the content of pyridine and pyrrole nitrogen structures were decreased, and some nitrogen structures were oxidized. Mercaptan (thioether) and sulfoxide(sulfone) were partly converted into inorganic sulfur and partly converted into the more stable thiophene structure.

Conformation and hydration property of low-acetyl gellan gum under microwave irradiation: Experiments and molecular dynamics simulations

The effect of microwave irradiation on the conformation and hydration properties of low-acetyl gellan gum was investigated to reveal the mechanism using experimental methods and molecular dynamics (MD) simulations. The experimental data showed that cross-sectional radius of gyration of the gellan chain treated by microwave or water bath were identical and microwave treatment could improve the water holding capability and restrict water mobility. On the other hand, results of root-mean-square deviation (RMSD) and root-mean-square fluctuation (RMSF) showed that microwave irradiation had little impact on the structural conformation of the low-acetyl gellan molecule. The analysis of radial distribution function and interaction energy demonstrated that microwaves modified the gellan-water molecules structure by energy transfer, making hydration shells of the gellan molecule become more structured. In addition, there was an enhancement of the average hydrogen bond number and lifetime under microwave irradiation due to rearrangement and reorient of molecules. These findings can explain the mechanism of microwave-promoted gellan gum gelation to some extent, which enhance industrial applications of low-acetyl gellan.

Enhancement of wood filled polymer by microwave induced heat treatment

A domestic microwave oven was modified using a thermocouple to measure temperature while heating to experiment the effect of microwave irradiation on Meranti wood. The main aspect of this research paper would be to evaluate the performance of heating on how it affects the wood by microwave irradiation. Wood is the testing specimen of this control system. The purpose of this study was to see if the microwave drying method had an effect on young’s moduli, tensile strength, and permeability. The results of the experimental tests demonstrate that Young's moduli increased as wood powder volume increased. The samples with 10 wt% of microwave-treated wood powder had the highest elasticity modulus, tensile strength and permeability of 4043 MPa, 15.41 MPa and 24.43% respectively. It was followed by Fourier-transform infrared spectroscopy (FTIR) analysis and followed by SEM (Scanning electron microscope analysis). Microwave treated wood at high intensities increased the elastic modulus and tensile strength by deeply impregnating the wood into the composite, according to morphological analysis performed using SEM.

Carbonyl compounds as contaminants migrating from the ecological vessels to food

The study examined the effects of organic vessels and cutlery on food quality. Low-molecular carbonyl compounds were treated as markers of undesirable changes. Migration tests were carried out at ambient and high temperatures for different times. The substitutes of food simulants A and B were pure water and acidified water, respectively. The analyze also was conducted using 20% ethanol (food simulant C). The effect of microwave radiation on migration intensity was also examined. Gas chromatography coupled to an electron capture detector (GC-ECD) and derivatization were used for determination of analytes at low concentration levels (ng/l). In general, a proportional relationship was observed between the contact time of the vessel with the simulant and the total concentration of identified carbonyl compounds. Acidic foods may be more contaminated with carbonyls than pH-neutral foods. Microwave heating can change the migration intensity of acetaldehyde and acetone. Sensory and instrumental analysis (GCxGC-TOF/MS) showed that some aldehydes migrating from dishes can affect the sensory properties of food.

Arc-Discharge Synthesis of ZnO:Ag Nanoparticles for Photocatalytic Applications: Effects of Aging, Microwave Radiation, and Voltage

Arc-Discharge Synthesis of ZnO:Ag Nanoparticles for Photocatalytic Applications: Effects of Aging, Microwave Radiation, and Voltage

Effect of microwave and ultrasonic irradiation on the enzymatic hydrolysis of water hyacinth biomass in the presence of surfactants

This paper presents the effect of microwave and ultrasound irradiation on the enzymatic hydrolysis of water hyacinth biomass in the presence of surfactants. Prior to hydrolyzing, the water hyacinth was treated utilizing alkali with and without microwave assistance. It was revealed that the microwave improved the removal of lignin and hemicellulose. The treated water hyacinth biomass was also characterized using Scanning Electron Microscope (SEM), X-ray Diffraction (XRD), and Fourier-Transform Infrared (FT-IR) Spectroscopy. The effect of surfactant and the assistance of microwave and ultrasound were comprehensively studied. Some parameters varied, including stirring speed, surfactant type, concentration, and reaction time. The results indicated that microwave and ultrasound could enhance the reaction rate. Tween 80 here could improve conventional, microwave-assisted, and ultrasound-assisted hydrolysis of water hyacinth biomass. It was found that the ultrasound-assisted hydrolysis was better than that of others. The results of this research can be used as the groundwork for further developing the lignocellulosic biomass hydrolysis process, especially in an advanced enzymatic hydrolysis process.

"Alternative thermal insulation building material manufactured by expanding the glass waste with anthracite under the effect of microwave radiation"

"Alternative thermal insulation building material manufactured by expanding the glass waste with anthracite under the effect of microwave radiation"

Effect of microwave irradiations on exchange bias and spin reorientation in cr doped iron oxide thin films – Sol-Gel approach

Effect of microwave irradiations on exchange bias and spin reorientation in cr doped iron oxide thin films – Sol-Gel approach

Effect of Microwave Irradiation on the Dielectric Characteristics of Semi-Conductive Nanoparticle-Based Nanofluids: Progress towards the Microwave Synthesis.

Studies on dispersing nanoparticles in base fluid to elevate its essential and critical properties have evolved significantly in the recent decade. Alongside the conventional dispersion techniques used for nanofluid synthesis, microwave energy at 2.4 GHz frequency is irradiated onto the nanofluids is experimented with in this study. The effect of microwave irradiation on the electrical and thermal properties of semi-conductive nanofluids (SNF) is investigated and presented in this article. Titanium dioxide and zinc oxide are the semi-conductive nanoparticles used for this study to synthesize the SNF, viz., titania nanofluid (TNF) and zinc nanofluid (ZNF). Flash and fire points are the thermal properties verified, and dielectric breakdown strength, dielectric constant (εr), and dielectric dissipation factor (tan δ) are the electrical properties verified in this study. AC breakdown voltage (BDV) of TNF and ZNF is improved by 16.78% and 11.25%, respectively, more than SNFs prepared without microwave irradiation. Results justify that the synergetic effect of stirring, sonication, and microwave irradiation in a rational sequence (microwave synthesis) exhibited better electrical and unaltered thermal properties. This microwave-applied nanofluid synthesis could be a simple and effective route to prepare the SNF with improved electrical properties.

Effect of microwave pre-treatment on protein extraction from de-oiled cottonseed meal and its functional and antioxidant properties

Malnutrition and environmental sustainability are two major global concerns today for health and wellbeing of society as well as for economic development and prosperity of country. Cottonseed protein offers to be a promising candidate and sustainable source of protein but presence of deleterious polyphenolic compound gossypol impedes its application for food purpose. Effect of microwave radiations on toxic compound and properties of protein (concentrate and isolate) i.e. physicochemical, functional and anti-nutritional properties is investigated in present study. Cottonseed meal (CSM) used for protein extraction in present study contains 4.13% total gossypol and 0.81% free gossypol. Microwave pretreatment of meal prior to extraction process has shown substantial reduction of 50.17% in values of total gossypol. Further, both the untreated cottonseed meal and microwave pretreated meal (MW-CSM) were proceeded for protein extraction. Alkali-salt assisted extraction of protein from both the meals have resulted in reduction of free gossypol and total gossypol below permissible limits i.e., 0.45% and 1.20%, respectively. Optimized freeze-dried microwaved pretreated protein isolate contains 7.07% moisture, 92.79% crude protein, 0.05% free gossypol, 1.14% total gossypol and ash content of 1.47%. According to research, microwave treated cottonseed protein isolate (MW-CSPI) has shown notable modifications in its functional and anti-nutritional properties of protein.

Effect of UV, IR and microwave radiation on Tween-80 porogen based low-k films

Low dielectric constant (low-k) films due to their potential application as an inter-layer dielectric (ILD) attracted significant attention of researchers and scientists. Porous low-k films like xerogel, aerogel, porogen based and hybrid films are extensively investigated as they have dielectric constant value less than that of SiO2. Considering the advantages of porous low-k films, current investigation focused onto the study of porogen based porous low-k films. To obtain low-k films, solgel based spin-on technique is used. Incorporation of Tween-80 porogen in deposited low-k films is confirmed through the presence of –CH2-CH3 group around 2856–2916 cm−1 in FTIR spectra. Removal of porogen material from film matrix was done by using radiation exposure of samples and is confirmed through FTIR analysis. Refractive indices (RI) of deposited porogen based films treated with UV, IR and microwave radiations are observed to be 1.28, 1.29 and 1.33, respectively. Further, density of IR, UV and microwave radiation is calculated from RI, and is observed to be decreased for UV radiation up to 1.38 gm/cm3. Dielectric constant value k = 2.7 was achieved for UV treated samples. Investigation suggests that low-k films having lower k value may have potential applications as ILD for ULSI technology.

Effect of Microwave Radiation on the Red Flour Beetle <i>Tribolium castaneum</i> (Herbst)

Approximately 50% of total harvested cereal grains are lost during the post-harvest handling and storage, and insects are the main cause for both quantity (reductions in weight) and quality. In the present study the effect of microwave radiation was studied on one of the stored product pest, the flour beetle Tribolium castaneum (Hersbt). Adult insects were obtained from infested flour products at stores specialized in selling cereal and stored products from Sakaka. Insects with its food media inside sac were exposed to microwave radiation for 15, 30, 45 and 60 sec for each radiation power. Tribolium castaneum beetles were exposed to microwave for 15, 30 and 45 sec. This result revealed that the mortality of immature and adults reached 100% in 15 and 45 sec, respectively.

The Effect of Microwave Radiation on the Self-Healing Performance of Asphalt Mixtures with Steel Slag Aggregates and Steel Fibers.

Self-healing in asphalt mixtures is a property that can be enhanced by external heating, which causes a thermal expansion that increases the flow of bitumen with reduced viscosity through the cracks. Therefore, this study aims to evaluate the effects of microwave heating on the self-healing performance of three asphalt mixtures: (1) conventional, (2) with steel wool fibers (SWF), and (3) with steel slag aggregates (SSA) and SWF. After evaluating the microwave heating capacity of the three asphalt mixtures with a thermographic camera, their self-healing performance was determined with fracture or fatigue tests and microwave heating recovery cycles. The results demonstrated that the mixtures with SSA and SWF promoted higher heating temperatures and presented the best self-healing capacity during the semicircular bending test and heating cycles, with significant strength recovery after a total fracture. In contrast, the mixtures without SSA presented inferior fracture results. Both the conventional mixture and that containing SSA and SWF presented high healing indexes after the four-point bending fatigue test and heating cycles, with a fatigue life recovery of around 150% after applying two healing cycles. Therefore, the conclusion is that SSA greatly influences the self-healing performance of asphalt mixtures after microwave radiation heating.

MICROWAVE TECHNOLOGY OF LIQUID-GLASS HEAT-INSULATING MATERIALS BASED ON A GRANULAR PRODUCT

The paper investigates the properties of liquid glass thermal insulation products obtained on the basis of granular products under the influence of microwave radiation. Due to the volumetric heat release in the thickness of the liquid glass composition, it is possible to obtain homogeneously structured materials by applying the technology of simultaneous porosization with volumetric expansion of both granules and binder. Thanks to volumetric heating and the mechanism of "non-thermal" effect of microwave radiation on the processing objects, the duration and temperature of their heating is significantly reduced, as well as the operational properties of the products are improved. The properties of materials obtained by this technology are compared with the properties of materials obtained by binding pre-swollen granules. It was proved that the simultaneous swelling of granules with a binder made it possible to obtain materials of a monolithic, uniformly porous structure with high physical and mechanical parameters and an order of magnitude lower indicators of water absorption and sorption moisture due to the dense packing of the granules and the uniform distribution of the binder in the intergranular space. The developed technology for the production of composite materials in the form of heat-insulating products of various configurations by means of simultaneous porosization with volume expansion of granules and binding under the action of microwave radiation allows to obtain materials with a better set of operational characteristics than in the case of binding pre-swollen granules at lower energy costs for their production because it excludes the stage of separate swelling of the granules. The resulting composite thermal insulation materials do not deform and have a fairly high strength for their average density. They are practically incompressible, and this is a very important fact, since the compression of heat insulating materials over time leads to an increase in its thermal conductivity and a decrease in the heat-shielding properties of the structure.

Comparative Numerical Study on the Weakening Effects of Microwave Irradiation and Surface Flux Heating Pretreatments in Comminution of Granite

Thermal pretreatments of rock, such as conventional heating and microwave irradiation, have received considerable attention recently as a viable method of improving the energy efficiency of mining processes that involve rock fracturing. This study presents a numerical analysis of the effects of thermal shock and microwave heating on the mechanical properties of hard, granite-like rock. More specifically, the aim is to numerically assess the reduction of uniaxial compressive strength of thermally pretreated specimens compared to intact ones. We also compare the performance of these two pretreatments (conventional heating and microwave irradiation) in terms of consumed energy and induced damage. Rock fracture is modelled by a damage-viscoplasticity model, with separate damage variables in tension and compression. A global solution strategy is developed for solving the thermo-mechanical problem (conventional heating) and the electromagnetic–thermo-mechanical problem (microwave heating). The electromagnetic part of the microwave heating problem is solved in COMSOL Multiphysics software Version 6.1 first. The electromagnetic solution is used as an input for the thermo-mechanical problem, which is finally solved by means of a staggered explicit solution method. Due to the predominance of the external thermal sources, the thermal and the mechanical parts of the problem in both cases are considered as uncoupled. Three-dimensional finite element simulations are utilized to study the damage-viscoplasticity model. An ore-shaped three-mineral numerical rock specimen is used in uniaxial compression tests.

An approach to determine the effect of microwave radiation as a tool for forensic veterinary pathology

An approach to determine the effect of microwave radiation as a tool for forensic veterinary pathology

Flavor characteristics of peeled walnut kernels under two-steps roasting processes

Currently, the effects of roasting methods on the flavor profile of peeled walnut kernels (PWKs) remain unknown. The effects of hot air binding (HAHA), radio frequency (HARF), and microwave irradiation (HAMW) on PWK were evaluated using olfactory, sensory, and textural techniques. Solvent Assisted Flavor Evaporation-Gas Chromatography–Olfactometry (SAFE-GC-O) identified 21 odor-active compounds with total concentrations of 229 μg/kg, 273 μg/kg and 499 μg/kg due to HAHA, HARF, and HAMW, respectively. HAMW exhibited the most prominent nutty taste, with the highest response among roasted milky sensors with the typical aroma of 2-ethyl-5-methylpyrazine. HARF had the highest values for chewiness (5.83 N·mm) and brittleness (0.68 mm); however, these attributes did not contribute to the flavor profile. The partial least squares regression (PLSR) model and VIP values showed 13 odor-active compounds were responsible for the sensory differences from different processes. The two-step treatment with HAMW improved the flavor quality of PWK.

Effects of microwave drying on the cell wall structures of round bamboo

Effects of microwave irradiation on bamboo cell wall structures were studied. Microwave treatment resulted in samples exhibiting smoother surfaces, deformed parenchyma cells, and increased porosity. Microwave treatment altered microfibril orientation through the formation of hydrogen bonds. The peak at 3440 cm-1, assigned to O-H stretching, decreased. Meanwhile, intermolecular and intramolecular bonds were formed, increasing the uniformity of microfibrils. Condensation reactions in surface hydroxyl groups and the formation of intramolecular hydroxyl groups in the amorphous region under microwave irradiation also improved the fiber arrangement uniformity. After treatment, the HCH and HOC bonds were reduced and the ester bonds were broken down. The methoxy and aromatic ring hydroxyl groups were oxidized, as indicated by the increase in the absorption peak at 148 ppm. The hydroxyl groups in the amorphous region near the fiber surface decreased, as did hemicellulose content, but there was an increase in secondary crystalline fibers.

A study on microwave absorption properties of polyaniline/nitrile rubber/graphene/Fe3O4 composites with a thickness of 0.7 mm and high flexibility

AbstractThe genotoxic effect of microwave radiation on humans is one of the leading causes of some diseases like cancer. Despite many reported materials for microwave absorption, there is still a demand for a super‐thin and flexible microwave absorber. In the present work, we synthesized Fe3O4/graphene/polyaniline/nitrile butadiene rubber composites with a thickness of 0.7 mm using a melt mixing method. Then, we comprehensively studied the electromagnetic and microwave absorption properties of the composites from 8 to 12 GHz. The composite with 38 wt% Fe3O4 and 6 wt% graphene exhibited the highest microwave absorption of more than 8 dB in the entire range of 8–12 GHz, with a minimum reflection loss of −14 dB at 10.3 GHz. By increasing the weight content of Fe3O4 and graphene, the imaginary part of dielectric permeability and magnetic permeability initially went up and then declined, resulting in poor impedance matching. Hence, we precisely controlled the weight content of the fillers to reach the highest impedance matching and attenuation constant. Consequently, this work opened up a unique way for developing super‐thin, lightweight, flexible microwave‐absorbing materials.