Journal articles on the topic 'Microwaves'
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1
Horikoshi, Satoshi, Yuhei Arai, and Nick Serpone. "In Search of the Driving Factor for the Microwave Curing of Epoxy Adhesives and for the Protection of the Base Substrate against Thermal Damage." Molecules 26, no. 8 (April 13, 2021): 2240. http://dx.doi.org/10.3390/molecules26082240.
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This study used controlled microwaves to elucidate the response of adhesive components to microwaves and examined the advantages of microwave radiation in curing epoxy adhesives. Curing of adhesives with microwaves proceeded very rapidly, even though each component of the adhesive was not efficiently heated by the microwaves. The reason the adhesive cured rapidly is that microwave heating was enhanced by the electrically charged (ionic) intermediates produced by the curing reaction. In contrast, the cured adhesive displayed lower microwave absorption and lower heating efficiency, suggesting that the cured adhesive stopped heating even if it continued to be exposed to microwaves. This is a definite advantage in the curing of adhesives with microwaves, as, for example, adhesives dropped onto polystyrene could be cured using microwave heating without degrading the polystyrene base substrate.
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Li, Guolin, Ting Shu, Chengwei Yuan, Jun Zhu, Jing Liu, Bing Wang, and Jun Zhang. "Simultaneous operation of X band gigawatt level high power microwaves." Laser and Particle Beams 28, no. 1 (January 21, 2010): 35–44. http://dx.doi.org/10.1017/s0263034609990541.
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AbstractAs the pulse power and high power microwave source technologies gradually matured, technologies for enhancing the output capacities of high power microwaves are becoming more and more attractive. In this paper, two different methods for the increasing of X band microwave powers are discussed: diplexers based on microwave filter and photonic crystal. For the case of diplexer based on microwave filter, the dual channel X band microwaves transmit through the filters with high efficiencies, the polarization and radiation directions for the microwaves are the same. With the application of metal photonic crystal, the reflection and transmission of TE/TM polarized X band microwaves are realized simultaneously; thus, the dual channel microwaves have the same radiation direction. A pulse of 25 ns, 3.9 GW has been successfully obtained. However, according to the experimental results, the internal breakdown in these devices limits their power handling capacities when the peak power and pulse duration of the microwaves increase. In the end, several methods for enhancing the power handling capacities the diplexer have been proposed.
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Qu, Ming Zhe. "Research on the Applications and Measurements of the Microwave Technology." Applied Mechanics and Materials 556-562 (May 2014): 3176–79. http://dx.doi.org/10.4028/www.scientific.net/amm.556-562.3176.
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Microwave technology is extensively used for point-to-point telecommunications. Microwaves are especially suitable for this use since they are more easily focused into narrower beams than radio waves, allowing frequency reuse; their comparatively higher frequencies allow broad bandwidth and high data transmission rates, and antenna sizes are smaller than at lower frequencies because antenna size is inversely proportional to transmitted frequency. Microwaves are used in spacecraft communication, and much of the world’s data, TV, and telephone communications are transmitted long distances by microwaves between ground stations and communications satellites. Microwaves are also employed in microwave ovens and in radar technology. The prefix “micro-” in “microwave” indicates that microwaves are “small” compared to waves used in typical radio broadcasting, in that they have shorter wavelengths. The boundaries between far infrared light, terahertz radiation, microwaves, and ultra-high-frequency radio waves are fairly arbitrary and are used variously between different fields of study.
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Saito, Yukie, Kousuke Nakano, Satoshi Shida, Tomoaki Soma, and Takanori Arima. "Microwave-enhanced release of formaldehyde from plywood." Holzforschung 58, no. 5 (August 1, 2004): 548–51. http://dx.doi.org/10.1515/hf.2004.083.
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Abstract The release of formaldehyde from plywood has been greatly reduced by treatment with microwave radiation. Formaldehyde emission in the air was measured before, during, and after 2.45-GHz microwave treatment. The concentration of formaldehyde released increased with microwave irradiation and, after the microwave treatment, decreased to a level below that of nontreated material. Microwaves were effective in releasing free formaldehyde from the plywood, which is preferable to it being emitted as “potential formaldehyde” via hydrolysis. Microwaves released formaldehyde from plywood samples more effectively compared to samples subjected to thermal energy from external heating. This suggests that microwaves directly activate free formaldehyde molecules, which have a polarity that is susceptible to microwaves. Microwave treatment is expected to be an effective way to reduce free formaldehyde emissions from wood-based materials containing resins.
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Ikeda, Yuji, and Joey Kim Soriano. "Volumetric Image Analysis Of Pulsed Non-Thermal Plasma Produced By Microwave." Proceedings of the International Symposium on the Application of Laser and Imaging Techniques to Fluid Mechanics 21 (July 8, 2024): 1–21. http://dx.doi.org/10.55037/lxlaser.21st.81.
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We have been developing microwave pulsed mode ignition system using 2.45 GHz microwaves. This technology has shown improvements in the lean combustion limit and fuel efficiency using a real engine with propane using a microwave discharged igniter (MDI). However, the MDI’s expensive parts are a major drawback when compared to common igniters. For practicality, we shifted to a more economical flat spiral igniter to generate plasma enabling stable and sustained non-equilibrium plasma in the atmosphere. Incorporating semiconductor elements, we miniaturized the microwave generator system, enhancing compactness and increasing its efficiency. Initial plasma was generated by the partial energy from the microwaves (1 mJ) and the sustained plasma was maintained in the atmosphere by the rest of the microwave’s energy. We varied long to short-pulsed modes, changed microwave pulse widths, increasing repetition rates which affecting plasma volume and stability. Our findings highlight the significance of microwave input patterns and the transition from thermal to non-equilibrium plasma. Future discussions should focus on the ignition mechanisms of various fuels and the transition from plasma source to initialization region. Our work contributes to the understanding and practical application of non-thermal plasma in combustion systems.
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Grygierzec, Beata, Krzysztof Słowiński, Stanisław Mazur, Sylwester Tabor, Angelika Kliszcz, Agnieszka Synowiec, Dariusz Roman Ropek, and Lidia Luty. "Condition of Young Japanese Knotweed (Reynoutria japonica Houtt.) Offshoots in Response to Microwave Radiation of Their Rhizomes." Agronomy 13, no. 11 (November 18, 2023): 2838. http://dx.doi.org/10.3390/agronomy13112838.
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Invasive Japanese knotweed is one of Poland’s most aggressive and difficult-to-control species. New methods of control are of utmost importance. This study aimed to analyze young knotweed offshoots’ regeneration and physiological condition after treatment of their rhizomes with microwaves of high frequency. The fresh rhizomes were microwaved in the laboratory once for different times (from 5 to 60 s, interval 5 s). Next, in the greenhouse, the growth of offshoots and their biochemical state (spectrophotometry of leaves) were recorded in three measurement series. It was shown that the microwave treatment for 35 s directly destroys knotweed rhizomes of a diameter of 1–3 cm, so it does not produce new offsprings. The treatment times from 5–25 s delay offspring regeneration and growth and development of leaves. The leaves initiate the mechanisms of protection against microwave stress in offshoots grown from the rhizomes exposed to microwaves for 10 s (increase in the anthocyanin index) and the 5 or 20 s treatments (higher values of the photochemical reflectance index). Based on the effective dose (ED50) analysis, the threshold of harmful effects of microwaves on the growth and development of Reynoutria japonica rhizomes was assumed to be 17–19 s.
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Zhao, Li, Chuanfu Yao, Hui Wang, Ji Dong, Jing Zhang, Xinping Xu, Haoyu Wang, et al. "Immune Responses to Multi-Frequencies of 1.5 GHz and 4.3 GHz Microwave Exposure in Rats: Transcriptomic and Proteomic Analysis." International Journal of Molecular Sciences 23, no. 13 (June 22, 2022): 6949. http://dx.doi.org/10.3390/ijms23136949.
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With the rapidly increasing application of microwave technologies, the anxiety and speculation about microwave induced potential health hazards has been attracting more and more attention. In our daily life, people are exposed to complex environments with multi-frequency microwaves, especially L band and C band microwaves, which are commonly used in communications. In this study, we exposed rats to 1.5 GHz (L10), 4.3 GHz (C10) or multi-frequency (LC10) microwaves at an average power density of 10 mW/cm2. Both single and multi-frequency microwaves induced slight pathological changes in the thymus and spleen. Additionally, the white blood cells (WBCs) and lymphocytes in peripheral blood were decreased at 6 h and 7 d after exposure, suggesting immune suppressive responses were induced. Among lymphocytes, the B lymphocytes were increased while the T lymphocytes were decreased at 7 d after exposure in the C10 and LC10 groups, but not in the L10 group. Moreover, multi-frequency microwaves regulated the B and T lymphocytes more strongly than the C band microwave. The results of transcriptomics and proteomics showed that both single and multi-frequency microwaves regulated numerous genes associated with immune regulation and cellular metabolism in peripheral blood and in the spleen. However, multi-frequency microwaves altered the expression of many more genes and proteins. Moreover, multi-frequency microwaves down-regulated T lymphocytes’ development, differentiation and activation-associated genes, while they up-regulated B lymphocytes’ activation-related genes. In conclusion, multi-frequency microwaves of 1.5 GHz and 4.3 GHz produced immune suppressive responses via regulating immune regulation and cellular metabolism-associated genes. Our findings provide meaningful information for exploring potential mechanisms underlying multi-frequency induced immune suppression.
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Yao, Chuanfu, Hui Wang, Liu Sun, Ke Ren, Ji Dong, Haoyu Wang, Jing Zhang, et al. "The Biological Effects of Compound Microwave Exposure with 2.8 GHz and 9.3 GHz on Immune System: Transcriptomic and Proteomic Analysis." Cells 11, no. 23 (November 30, 2022): 3849. http://dx.doi.org/10.3390/cells11233849.
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It is well-known that microwaves produce both thermal and nonthermal effects. Microwave ablation can produce thermal effects to activate the body’s immune system and has been widely used in cancer therapy. However, the nonthermal effects of microwaves on the immune system are still largely unexplored. In the present study, we exposed rats to multifrequency microwaves of 2.8 GHz and 9.3 GHz with an average power density of 10 mW/cm2, which are widely used in our daily life, to investigate the biological effects on the immune system and its potential mechanisms. Both single-frequency microwaves and multifrequency microwaves caused obvious pathological alterations in the thymus and spleen at seven days after exposure, while multifrequency microwaves produced more pronounced injuries. Unexpectedly, multifrequency microwave exposure increased the number of both leukocytes and lymphocytes in the peripheral blood and upregulated the proportion of B lymphocytes among the total lymphocytes, indicating activation of the immune response. Our data also showed that the cytokines associated with the proliferation and activation of B lymphocytes, including interleukin (IL)-1α, IL-1β and IL-4, were elevated at six hours after exposure, which might contribute to the increase in B lymphocytes at seven days after exposure. Moreover, multifrequency microwave exposure upregulated the mRNA and protein expression of B cell activation-associated genes in peripheral blood. In addition to immune-associated genes, multifrequency microwaves mainly affected the expression of genes related to DNA duplication, cellular metabolism and signal transduction in the peripheral blood and spleen. In conclusion, multifrequency microwaves with 2.8 GHz and 9.3 GHz caused reversible injuries of the thymus and spleen but activated immune cells in the peripheral blood by upregulating mRNA and protein expression, as well as cytokine release. These results not only uncovered the biological effects of multifrequency microwave on the immune system, but also provide critical clues to explore the potential mechanisms.
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Yuchen, Li. "Application of Microwave Technology in Different Fields for Energy Saving and Emission Reduction." Chinese Sustainable Development Review 2, no. 2 (June 28, 2023): 26–36. http://dx.doi.org/10.48014/csdr.20230406001.
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In today's world, security of energy supply and greenhouse gas emissions due to rising energy demand are seriously threatening sustainable energy development, and it is urgent to promote energy structure reform. Microwave, as a clean and environmentally friendly green energy source, has developed rapidly in recent years. Unlike traditional heating methods, microwave heating generates heat through the random motion of polar molecules. This results in microwave heating having the advantages of selective heating, fast temperature rise, easy control and high heating efficiency. This allows microwaves to make a contribution in advancing the reform. of the energy mix. This paper investigates the use of microwave technology in different industries to save energy and reduce emissions. It finds that in the ironmaking industry, microwaves can speed up the reduction time of iron ore, reduce carbon dioxide emissions, while making iron ore more easier to crush and magnetically sort during iron ore pretreatment process. In the food industry, microwaves can reduce the time required to cook and dry, and maximise the retention of nutrients in food. In the field of waste recycling, microwaves reduce the volume of bottom radioactive waste in a shorter time and improve the efficiency of desulphurisation of waste rubber. In the Budur reaction, microwaves reduce the temperature required for the reaction and increase the conversion of carbon dioxide. After summarising the advantages of microwave technology, this paper also analyses the current shortcomings of microwave technology, introduces microwave-related patents and concludes with an outlook on the future of microwave technology.
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Milojevic, Natasa, D. Stanisavljev, Biljana Nikolic, M. Beljanski, Ljiljana Kolar-Anic, and Jelena Knezevic-Vukcevic. "Bacteriophage λ proliferation in Escherichia coli under the influence of microwave irradiation." Archives of Biological Sciences 62, no. 4 (2010): 935–40. http://dx.doi.org/10.2298/abs1004935m.
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The influence of microwaves on bacterial metabolism was investigated using the proliferation of bacteriophage ? in Escherichia coli cells as a model system. All experiments were performed under the same microwave absorption rate and constant temperature. Microwave treatment had no effect on bacterial or phage viability, or on phage adsorption. Microwaves significantly influenced phage proliferation but the effects depended on the experimental temperature. The kinetics of phage proliferation decreased with irradiation at the optimal temperature and increased at the suboptimal temperature. This result could be ascribed to the specific thermal effects of microwaves.
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Adhiksana, Arief, Andi Jumardi, Kusyanto, and Rina Andriani. "PEMANFAATAN GELOMBANG MIKRO DALAM EKSTRAKSI ANTOSIANIN DARI KULIT BUAH NAGA SEBAGAI PENGGANTI RHODAMIN B UNTUK SEDIAAN PEWARNA BIBIR ALAMI." Journal of Research and Technology 3, no. 1 (June 30, 2017): 63–69. http://dx.doi.org/10.55732/jrt.v3i1.812.
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Today, microwave can be used in various chemical processes. The advantage of microwaves is able to deliver energy directly to the material. One of microwave application is the extraction process of natural materials. Microwaves can be used to reduce extraction process time of the anthocyanin from the dragon fruit skin. This research aims to determine the solvent extracted effect to the anthocyanin extraction of dragon fruit skin using microwaves. The solvent used was 95% ethanol, 85% ethanol, 75% ethanol, 95% ethanol –citric acid, 85% ethanol -acids and 75% - citric acid ethanol to the anthocyanin extraction results of dragon fruit skin extracted using microwaves. The consumption of microwave power is 400 watt with 50 gram of dragon fruits skin. Then, anthocyanin extracts are mixed with supporting materials to be made as lipstick and proposed for topical and favorite test. The best yield can be obtained by using ethanol-citric acid solvent at 25,031%.
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Li, G. L., C. W. Yuan, J. Y. Zhang, T. Shu, and J. Zhang. "A diplexer for gigawatt class high power microwaves." Laser and Particle Beams 26, no. 3 (June 25, 2008): 371–77. http://dx.doi.org/10.1017/s0263034608000384.
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AbstractWith the rapid development of high power microwave (HPM) technologies, HPM devices with several output frequencies are becoming more and more attractive. Diplexer is a microwave device with two output frequencies, here, an L/X band diplexer with novel structure is tried to be employed in the HPM system. In order to obtain the same radiation direction for the L and X band microwaves in the diplexer, the reflection of L band microwaves and transmission of X band microwaves are realized by an array of irises. To obtain the required performance, the width and thickness of the irises and the distance between them should be well chosen. The diplexer is investigated through theoretical analysis and numerical computation, and the final design described in this work, is the result of an overall optimization process. In simulation, both the reflectivities of L-band microwaves and the transmissivities of X band microwaves reach 99.5%, and the power handling capacity of the diplexer is higher than 5.6 gigawatt (GW). Then, the L/X band diplexer is designed and fabricated according to the optimized results. After that, a series of experiments are carried out to test the diplexer. The cold test results show that the reflectivities of L band microwaves are as high as 97.5%, and the transmissivities of X band microwaves are up to 98.8%, and the acquired radiation patterns show that the designed diplexer is suitable for the diplexing of L/X band microwaves, in a word, the cold test results of the diplexer are in good agreement with the simulational results. In the end, the diplexer is tested with GW class HPMs. The radiated HPMs have little change in the pulse duration and magnitude with the diplexer applied, that is to say, there is no microwave breakdown during the HPM reflection and transmission.
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Handayani, S. U., Sutrisno, D. Ariwibowo, R. Amalia, and M. E. Yulianto. "OPTIMIZATION OF CONTINUOUS MICROWAVE INACTIVATOR FOR POLYPHENOL OXIDASE INACTIVATION ON GREEN TEA PROCESSING USING RESPONSE SURFACE METHODOLOGY." RASAYAN Journal of Chemistry 15, no. 02 (2022): 798–805. http://dx.doi.org/10.31788/rjc.2022.1526318.
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Microwave treatment is a promising technology for food processing such as drying, extraction, and enzyme inactivation because of its ionic heat transfer. This study develops and optimizes the fixation process in green tea using a microwave-based enzyme inactivator. A continuous microwave enzyme inactivator with a dimension of 3300 (L) × 550 (W) × 600 mm3 (H) was built to study the effect of temperature, microwave radiation time, and the number of microwaves on the catechin content of green tea. The optimum condition for the inactivation process was determined using response surface methodology and central composite design. The result shows that the model can predict the effect of temperature, microwave radiation time, and the number of microwaves on catechin content. Temperature, fixation time (conveyor velocity), and the number of microwaves, have a significant impact on enzyme inactivation when using a continuous microwave. The optimum microwave inactivation condition for polyphenol oxidase enzyme was four at 70C temperature and 30 rpm conveyor speed.
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VIDAČEK, SANJA, CRISTINA DE LAS HERAS, MARIA TERESA SOLAS, MARIA LUISA GARCÍA, ANGEL MENDIZÁBAL, and MARGARITA TEJADA. "Viability and Antigenicity of Anisakis simplex after Conventional and Microwave Heating at Fixed Temperatures." Journal of Food Protection 74, no. 12 (December 1, 2011): 2119–26. http://dx.doi.org/10.4315/0362-028x.jfp-11-108.
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Inactivation of parasites in food by microwave treatment may vary due to differences in the characteristics of microwave ovens and food properties. Microwave treatment in standard domestic ovens results in hot and cold spots, and the microwaves do not penetrate all areas of the samples depending on the thickness, which makes it difficult to compare microwave with conventional heat treatments. The viability of Anisakis simplex (isolated larvae and infected fish muscle) heated in a microwave oven with precise temperature control was compared with that of larvae heated in a water bath to investigate any additional effect of the microwaves. At a given temperature, less time was required to kill the larvae by microwaves than by heated water. Microwave treatment killed A. simplex larvae faster than did conventional cooking when the microwaves fully penetrated the samples and resulted in fewer changes in the fish muscle. However, the heat-stable allergen Ani s 4 was detected by immunohistochemistry in the fish muscle after both heat treatments, even at 70°C, suggesting that Ani s 4 allergens were released from the larvae into the surrounding tissue and that the tissues retained their allergenicity even after the larvae were killed by both heat treatments. Thus, microwave cooking will not render fish safe for individuals already sensitized to A. simplex heat-resistant allergens.
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Sze, H., J. Benford, and W. Woo. "High-power microwave emission from a virtual cathode oscillator." Laser and Particle Beams 5, no. 4 (November 1987): 675–81. http://dx.doi.org/10.1017/s0263034600003189.
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Pinched electron beams emit high power microwaves by formation of a virtual cathode. Radiation occurs simultaneously with pinching or slightly thereafter. Observations of strong electrostatic fields and the partitioning of current into reflexing and transmitting populations at the same time that microwaves are emitted indicate virtual cathode formation. Microwaves originate mainly from the virtual cathode side of the anode. A two-dimensional model for the electron flow in the presence of a virtual cathode is presented. The model allows for electron reflexing and velocity distribution spread. Solutions with strong radial flow agree closely with microwave measurements, and result in the microwave frequency scaling linearly with diode current.
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Mierzwa, Dominik, and Justyna Szadzińska. "An Investigation of the Use of Microwaves and Airborne Ultrasound in the Convective Drying of Kale: Process Efficiency and Product Characteristics." Sustainability 15, no. 23 (November 22, 2023): 16200. http://dx.doi.org/10.3390/su152316200.
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This study evaluated different hybrid drying modes, combining traditional convective drying with microwave radiation and airborne ultrasound for the dehydration of green leafy vegetables. The central composite design method was used to analyze the impact of microwave and ultrasonic waves on kinetics, energy consumption, and various quality parameters, like color, ascorbic acid, polyphenol, carotenoid, and chlorophyll content in Brassica oleracea, var. acephala. The results of the applied experimental design, i.e., the surface response methodology, showed that the application of microwaves and ultrasound decreased the drying time considerably and enhanced the moisture evaporation from the kale leaves, significantly improving the drying rate and energy efficiency. The drying rate increase demonstrated varying results with changes in air temperature. Specifically, ultrasound resulted in a 69–100% increase, microwaves in a 430–698% increase, and a combination of ultrasound and microwaves in a 463–950% increase at 70 and 50 °C, respectively. Specific energy consumption decreased by 42–51% for ultrasound, 80–87% for microwaves, and 82–90% for ultrasound and microwaves at 70 and 50 °C, respectively. The drying parameters were also found to be better at a higher temperature, but the increase in the drying rate caused by microwaves and ultrasound was notably lower. Moreover, the analysis of the key kinetic parameters and material qualities led to the conclusion that the synergistic action of microwave- and ultrasound-assisted convection contributes to better drying effectiveness and product quality, demonstrating greater retention of vitamin C, phenolics, and natural dyes of up to 90%.
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Bartoli, Frediani, Briens, Berruti, and Rosi. "An Overview of Temperature Issues in Microwave-Assisted Pyrolysis." Processes 7, no. 10 (September 26, 2019): 658. http://dx.doi.org/10.3390/pr7100658.
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Microwave-assisted pyrolysis is a promising thermochemical technique to convert waste polymers and biomass into raw chemicals and fuels. However, this process involves several issues related to the interactions between materials and microwaves. Consequently, the control of temperature during microwave-assisted pyrolysis is a hard task both for measurement and uniformity during the overall pyrolytic run. In this review, we introduce some of the main theoretical aspects of the microwaves–materials interactions alongside the issues related to microwave pyrolytic processability of materials.
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Pandey, Aditya, Omeed Momeni, and Pramod Pandey. "Quantitative Analysis of Genomic DNA Degradation of E. coli Using Automated Gel Electrophoresis under Various Levels of Microwave Exposure." Gels 10, no. 4 (April 2, 2024): 242. http://dx.doi.org/10.3390/gels10040242.
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The problem that this study addresses is to understand how microwave radiation is able to degrade genomic DNA of E. coli. In addition, a comparative study was made to evaluate the suitability of a high-throughput automated electrophoresis platform for quantifying the DNA degradation under microwave radiation. Overall, this study investigated the genomic DNA degradation of E. coli under microwave radiation using automated gel electrophoresis. To examine the viable organisms and degradation of genomic DNA under microwave exposure, we used three methods: (1) post-microwave exposure, where E. coli was enumerated using modified mTEC agar method using membrane filtration technique; (2) extracted genomic DNA of microwaved sample was quantified using the Qubit method; and (3) automated gel electrophoresis, the TapeStation 4200, was used to examine the bands of extracted DNA of microwaved samples. In addition, to examine the impacts of microwaves, E. coli colonies were isolated from a fecal sample (dairy cow manure), these colonies were grown overnight to prepare fresh E. coli culture, and this culture was exposed to microwave radiation for three durations: (1) 2 min; (2) 5 min; and (3) 8 min. In general, Qubit values (ng/µL) were proportional to the results of automated gel electrophoresis, TapeStation 4200, DNA integrity numbers (DINs). Samples from exposure studies (2 min, 5 min, and 8 min) showed no viable E. coli. Initial E. coli levels (at 0 min microwave exposure) were 5 × 108 CFU/mL, and the E. coli level was reduced to a non-detectable level within 2 min of microwave exposure. The relationships between Qubit and TapeStation measurements was linear, except for when the DNA level was lower than 2 ng/µL. In 8 min of microwave exposure, E. coli DNA integrity was reduced by 61.7%, and DNA concentration was reduced by 81.6%. The overall conclusion of this study is that microwave radiation had a significant impact on the genomic DNA of E. coli, and prolonged exposure of E. coli to microwaves can thus lead to a loss of genomic DNA integrity and DNA concentrations.
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Kakar, Uzair Mohammad, Atiqullah Sarwari, Mustafa Rahime, Mohammad Hassan Hassand, and Parwiz Niazi. "Revolutionizing Food Processing: A Comprehensive Review of Microwave Applications." European Journal of Theoretical and Applied Sciences 2, no. 2 (March 1, 2024): 38–47. http://dx.doi.org/10.59324/ejtas.2024.2(2).04.
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The review explores the extensive applications of microwaves, covering the non-ionizing radiation spectrum from 300 MHz to 300 GHz. It emphasizes the growing role of microwaves in modern food technology, delving into their evolution, principles, advantages, and drawbacks, the analysis delves into the unique dynamics of microwave heating, considering factors like frequency, permittivity, and thermal properties. Microwaves offer benefits such as fast and even cooking, nutrient preservation, and improved thermodynamic output, the use of radiation in sterilization, drying, pasteurization, and blanching, showcasing their efficiency in achieving product sterility while minimizing nutrient damage. Microwaves are important for modern food processing to meet dietary needs.
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Mogildea, Marian, George Mogildea, Valentin Craciun, and Sorin I. Zgura. "The Effects Induced by Microwave Field upon Tungsten Wires of Different Diameters." Materials 14, no. 4 (February 22, 2021): 1036. http://dx.doi.org/10.3390/ma14041036.
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The effects induced by microwave field upon tungsten wires of different diameters were investigated. Tungsten wires with 0.5 and 1.0 mm diameters were placed in the focal point of a single-mode cylindrical cavity linked to a microwave generator and exposed to microwave field in ambient air. The experimental results showed that the 0.5 mm diameter wire was completely vaporized due to microwaves strong absorption, while the wire with 1 mm diameter was not ignited. During the interaction between microwaves and tungsten wire with 0.5 mm diameter, a plasma with a high electronic excitation temperature was obtained. The theoretical analysis of the experiment showed that the voltage generated by metallic wires in interaction with microwaves depended on their electric resistance in AC and the power of the microwave field. The physical parameters and dimension of the metallic wire play a crucial role in the ignition process of the plasma by the microwave field. This new and simple method to generate a high-temperature plasma from a metallic wire could have many applications, especially in metal oxides synthesis, metal coatings, or thin film deposition.
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Gedye, Richard N., Werner Rank, and Kenneth C. Westaway. "The rapid synthesis of organic compounds in microwave ovens. II." Canadian Journal of Chemistry 69, no. 4 (April 1, 1991): 706–11. http://dx.doi.org/10.1139/v91-106.
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Using microwaves to carry out organic reactions does not significantly alter the product composition. The small changes in product composition that are observed when microwaves are used arise because the microwave reactions occur at higher temperatures than reflux reactions. The results demonstrate that ions in the reaction mixture alter the heating rate of the microwave reactions. Although scaling-up the reaction leads to a slightly lower rate of reaction (lower percentage yield), one still retains large rate enhancements. Key words: microwave, synthesis, product composition, scale-up, ionic strength effects.
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Binner, Jon, and Bala Vaidhyanathan. "When Should Microwaves Be Used to Process Technical Ceramics?" Materials Science Forum 606 (October 2008): 51–59. http://dx.doi.org/10.4028/www.scientific.net/msf.606.51.
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This paper attempts to shed light on why the stand alone microwave processing of technical ceramics, despite being one of the most popular field with respect to volume of research performed, is still struggling to achieve priority status with respect to commercialisation. To obtain some answers to this enigma and determine when microwaves should be used to process technical ceramics, three case studies are explored. The conclusion is that microwaves should be used to process technical ceramics when specific advantage can be taken of the intrinsic nature of microwave energy and not simply as an alternative energy source. In addition, it is concluded that from a commercialisation view point hybrid processing is often a better approach than the use of pure microwaves.
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Kayamori, Fumihiro, Hiroyuki Togashi, Natsumi Endo, Makoto Ozaki, Kan Hirao, Yonejiro Arimoto, Ryuji Osawa, et al. "Development of a CaCO3 Precipitation Method Using a Peptide and Microwaves Generated by a Magnetron." Processes 12, no. 7 (June 26, 2024): 1327. http://dx.doi.org/10.3390/pr12071327.
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Microwave applications, such as microwave ovens and mobile phones, are ubiquitous and indispensable in modern society. As the utilization of microwave technology is becoming more widespread, the effects of microwaves on living organisms and physiological processes have received increased attention. This study aimed to investigate the effects of microwaves on calcium carbonate biomineralization as a model biochemical process. A magnetron oscillator was used to generate 2450 MHz microwaves because magnetrons are relatively inexpensive and widespread. We conducted transmission electron microscopy (TEM), atomic force microscopy (AFM), TEM-electron energy-loss spectroscopy (EELS), dynamic light scattering (DLS), and high-performance liquid chromatography (HPLC) measurements to analyze the calcium carbonate precipitates. Our findings showed the formation of string-like precipitates of calcium carbonate upon microwave irradiation from one direction, similar to those obtained using a semiconductor oscillator, as reported previously. This implied that the distribution of the frequency had little effect on the morphology. Furthermore, spherical precipitates were obtained upon microwave irradiation from two directions, indicating that the morphology could be controlled by varying the direction of microwave irradiation. Magnetrons are versatile and also used in large-scale production; thus, this method has potential in medical and industrial applications.
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Yao, Chuanfu, Ji Dong, Ke Ren, Liu Sun, Hui Wang, Jing Zhang, Haoyu Wang, et al. "Accumulative Effects of Multifrequency Microwave Exposure with 1.5 GHz and 2.8 GHz on the Structures and Functions of the Immune System." International Journal of Environmental Research and Public Health 20, no. 6 (March 12, 2023): 4988. http://dx.doi.org/10.3390/ijerph20064988.
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Microwave ablation can produce immune activation due to thermal effects. However, the nonthermal effects of microwaves on the immune system are still largely unexplored. In this study, we sequentially exposed rats to 1.5 GHz microwave for 6 min and 2.8 GHz microwave for 6 min at an average power density of 5, 10, and 30 mW/cm2. The structure of the thymus, spleen, and mesenteric lymph node were observed, and we showed that multifrequency microwave exposure caused tissue injuries, such as congestion and nuclear fragmentation in lymphocytes. Ultrastructural injuries, including mitochondrial swelling, mitochondrial cristae rupture, and mitochondrial cavitation, were observed, especially in the 30 mW/cm2 microwave-exposed group. Generally, multifrequency microwaves decreased white blood cells, as well as lymphocytes, monocytes, and neutrophils, in peripheral blood, from 7 d to 28 d after exposure. Microwaves with an average density of 30 mW/cm2 produced much more significant inhibitory effects on immune cells. Moreover, multifrequency microwaves at 10 and 30 mW/cm2, but not 5 mW/cm2, reduced the serum levels of several cytokines, such as interleukin-1 alpha (IL-1α), IL-1β, interferon γ (IFN-γ) and tumor necrosis factor α (TNF-α), at 7 d and 14 d after exposure. We also found similar alterations in immunoglobulins (Igs), IgG, and IgM in serum. However, no obvious changes in complement proteins were detected. In conclusion, multifrequency microwave exposure of 1.5 GHz and 2.8 GHz caused both structural injuries of immune tissues and functional impairment in immune cells. Therefore, it will be necessary to develop an effective strategy to protect people from multifrequency microwave-induced immune suppression.
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Qin, Yu Rong, Ni Chen, Hao Lin, Dong Li Huang, and Zhi Yong Zhang. "Study on the Factors Influencing on the Variation of the Temperature in Cell Suspensions Exposed to Microwaves Based on the Temperature Sensor Technique." Applied Mechanics and Materials 239-240 (December 2012): 836–39. http://dx.doi.org/10.4028/www.scientific.net/amm.239-240.836.
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Because of convenient and price cheap, microwave therapy is an effective method to treat leukemia now. However it is quite difficult to detect with nondestrctive method and control accurately the temperature inside the purifying material exposed to microwaves. If the temperature is lower, the luekimic cell can not be killed effectively. But if the temperature is too high, the normal and cancer cell should be killed together. In this paper, the influence factors on the temperature variation in suspensions exposed to microwaves were studied so as to the temperature can be controlled effectively. The results show that there are many factors influencing on the temperature change in suspensions exposed to microwaves, and among them the influence of microwaves power is the biggest. The surface temperature was measured by a temperature sensor, then the inside temperature can be calculated according to the difference between inside and outside liquids. Further, an automatic control system of microwave power was used to control the inside temperature in an appropriate range, at which the normal cells were protected and the cancer cell were killed effectively.
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Iadarola, Linda, and Paul Webster. "Can Microwave Ovens Reduce Immunocytochemical Labeling Times?" Proceedings, annual meeting, Electron Microscopy Society of America 54 (August 11, 1996): 38–39. http://dx.doi.org/10.1017/s042482010016265x.
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In recent years the use of microwave ovens in biomedical microscopy laboratories has contributed to reducing the times of fixation and resin embedding. Reports of the use of microwaves for histochemsitry and immunocytochemistry led us to investigate the possible use of a microwave oven to reduce immunocytochemical labeling protocols.The application of specific antibodies to thawed cryosections of aldehyde-fixed material is becoming more accessible to research and service laboratories. These detection methods, routinely performed in our laboratory, were used to study the effect of microwaves on labeling protocols using affinity purified, polyclonal antibodies and protein A-gold.Cells containing 3-(2,4-dinitroanilino)-3-arnino-N-methyldipropylamine (DAMP), a compound which accumulates in low pH compartments, were aldehyde-fixed, cryosectioned and then labeled with rabbit antibodies to dinitrophenol (which bind to DAMP) and 10nm protein-A gold. Regular sequential labeling protocols were compared with protocols using a microwave oven operating at 100% power, where the antibody incubation and washing times were reduced. The effect of microwaves on the labeling efficiency was investigated using simple quantitative methods. The protocol which produced reduced incubation times with no loss of labeling efficiency was then applied to sections in the absence of microwaves. The effect of reducing the final methyl cellulose-uranyl acetate contrasting step was also investigated.
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Fukushima, Jun, Keiichiro Kashimura, and Hirotsugu Takizawa. "Nitridation Reaction of Titanium Powders by 2.45 GHz Multimode Microwave Irradiation using a SiC Susceptor in Atmospheric Conditions." Processes 8, no. 1 (December 21, 2019): 20. http://dx.doi.org/10.3390/pr8010020.
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A titanium nitride (TiN) coating using microwaves can be accomplished in air, and satisfies the required conditions of an on-demand TiN coating process. However, the coating mechanism using microwaves is not completely clear. In this study, to understand the detailed mechanism of microwave titanium nitridation in air, the quantity of nitrogen and oxygen in reacted TiN powder has been investigated by an inert melting method. Titanium powders were irradiated with microwaves by a multi-mode type 2.45 GHz microwave irradiation apparatus, while also being held at various temperatures for two different dwell times. X-ray diffraction (XRD) results revealed that nitridation of the powder progressed with increasing process temperature, and the nitridation corresponds to the powder color after microwave irradiation. The nitrogen contents of the samples increased with increasing processing temperature and dwell time, unlike oxygen. It is postulated that the reaction of convected air with titanium is a key role to control nitridation in this system.
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Walsh, Gerald E., Patrice M. Bohannon, and Paul B. Wessinger-Duvall. "Microwave irradiation for rapid killing and fixing of plant tissue." Canadian Journal of Botany 67, no. 4 (April 1, 1989): 1272–74. http://dx.doi.org/10.1139/b89-167.
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Irradiation by microwaves allows for rapid killing and fixing of plant tissue, with excellent cellular integrity for histological examination. Two exposures to microwaves for 3 s in formalin – acetic acid – alcohol gave good preservation of nuclei, chloroplasts, and other plant structures. The microwave method offers a considerable saving of time over traditional methods for killing and fixing plant tissue.
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Sano, Saburo, Sadatsugu Takayama, and Akira Kishimoto. "Microwave Absorbency Change of Nitride Powders under Vacuum Heating." Advances in Science and Technology 88 (October 2014): 31–36. http://dx.doi.org/10.4028/www.scientific.net/ast.88.31.
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We measured the microwave and millimeter-wave behaviors of ceramics and metal powders as a basis for developing microwave and millimeter-wave heating technology. In this study, nitride powders were subjected to microwave absorption measurements at elevated temperature. These measurements were performed using a system comprising a vector network analyzer, a circular wave-guide fixture, and a vacuum furnace. The sample’s microwave absorbency was evaluated by the change in reflection power from the sample in the circular wave-guide fixture under vacuum heating. Measurements were performed at approximately 24 GHz and at temperature up to approximately 1100°C. Boron nitride (BN) exhibited almost no absorption of microwaves up to 1100°C, similar to the results of a low-loss oxide powder such as alumina. Dichromium mononitride (Cr2N) powder exhibited a rather high absorption of microwaves at room temperature. During vacuum heating, absorbency of Cr2N started to decrease at 300°C, and became almost zero at temperature greater than 600°C, similar to the behavior of iron powder. This result indicated that roughly packed Cr2N powder absorbs microwave radiation; however, during vacuum heating, the compact body was sintered and the whole sample body became a reflector of microwaves. This change was irreversible, and the sample maintained its reflection behavior upon the cooling. When a mixed powder of Cr2N (20 mass%) and Al2O3 was heated under vacuum, the compact sample exhibited microwave absorption that increased with increasing temperature. This change was reversible upon cooling. These results indicated that the mixed powder did not become reflector of microwaves; Cr2N particles were not electrically connected each other because the Al2O3 particles kept the Cr2N particles separate during the vacuum heating process.
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Balakrishnan, E., M. I. Nelson, and X. D. Chen. "Microwave assisted ignition to achieve combustion synthesis." Journal of Applied Mathematics and Decision Sciences 5, no. 3 (January 1, 2001): 151–64. http://dx.doi.org/10.1155/s1173912601000128.
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The use of microwave heating to initiate combustion synthesis has been increasingly investigated in recent years because of its advantages over traditional methods. A simple mathematical model is used to model these experiments. The microwave power absorption term is modelled as the product of an Arrhenius reaction term with a function that decays exponentially with distance. The former represents the temperature-dependent absorption of the microwaves whereas the latter describes the penetration of the material by the microwaves. Combustion kinetics are modelled as a first-order Arrhenius reaction.
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Horikoshi, Satoshi, Yuuhei Arai, Iftikhar Ahmad, Clayton DeCamillis, Keith Hicks, Bob Schauer, and Nick Serpone. "Application of Variable Frequency Microwaves in Microwave-Assisted Chemistry: Relevance and Suppression of Arc Discharges on Conductive Catalysts." Catalysts 10, no. 7 (July 11, 2020): 777. http://dx.doi.org/10.3390/catal10070777.
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The application and advantages of variable frequency microwaves (VFM; range, 5.85–6.65 GHz) are reported for the first time in microwave chemistry, particularly when carrying out reactions catalyzed by metallic conductive catalysts so as to avoid the formation of arc discharges, and especially when using a strong microwave absorber such as activated carbon (AC) particulates as supports of metal-based catalysts. Two model reactions performed in low boiling point nonpolar solvents are described wherein arc discharges easily occur under the more conventional fixed frequency microwave (FFM) approach: (i) the synthesis of 4-methylbiphenyl (4MBP) by the Suzuki-Miyaura cross-coupling process catalyzed by Pd particles supported on AC particulates (Pd/AC), and (ii) the synthesis of toluene via the dehydrogenation of methylcyclohexane (MCH) catalyzed by Pt particles dispersed on AC particulates (Pt/AC). Contrary to the usage of fixed frequency microwaves (5.85 GHz and 6.65 GHz), the use of VFM microwaves increased the chemical yields of 4MBP {49% versus 5–8% after 60 min} and toluene {89% versus 24% after 10 min} by suppressing the formation of discharges that otherwise occur on the catalyst/AC surface with FFM microwaves. Consequently, relative to the latter approach, the VFM technology is significantly advantageous, especially in reactions with solid conductive catalysts, not least of which are the reduction in power consumption, thus energy savings, and the prevention of potential mishaps.
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Jayasanka, Senavirathna Mudalige Don Hiranya, and Takashi Asaeda. "The significance of microwaves in the environment and its effect on plants." Environmental Reviews 22, no. 3 (September 2014): 220–28. http://dx.doi.org/10.1139/er-2013-0061.
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Wireless technologies are becoming popular due to convenient lower implementation costs and operational costs compared with wired technologies. Various wireless internet and communication technologies, such as worldwide interoperability for microwave access (WiMAX) and long-term evolution (LTE), are expanding rapidly. As with mobile phones, all of these technologies operate using high-frequency electromagnetic waves in the microwave category (3 × 102 – 3 × 106 MHz). An increasing number of operators within a geographical area is resulting in high microwave densities in the environment. At the same time, wireless technologies are now utilizing radio frequency electromagnetic radiation of up to 5500 MHz, and frequency spectrum allocation tables indicate that countries have allocated additional high frequencies for broadcasting purposes. Scientists have widely investigated the effects of microwaves on humans and animals, and some findings confirm that such effects exist. In comparison, a very limited number of published studies have addressed the effects of microwaves on plants. The findings of these studies indicate that the effects of microwaves on plants depend on the plant family and growth stage involved as well as the exposure duration, frequency, and power density, among other factors. However, the number of published studies is not yet sufficient to support drawing strong conclusions regarding the effects of microwaves on whole plant communities. Therefore, further studies are necessary to support present findings and uncover new findings.
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Belkhir, Kedafi, Guillaume Riquet, and Frédéric Becquart. "Polymer Processing under Microwaves." Advances in Polymer Technology 2022 (May 6, 2022): 1–21. http://dx.doi.org/10.1155/2022/3961233.
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Over the last decades, microwave heating has experienced a great development and reached various domains of application, especially in material processing. In the field of polymers, this unusual source of energy showed important advantages arising from the direct microwave/matter interaction. Indeed, microwave heating allows regio-, chemio-, and stereo-selectivity, faster chemical reactions, and higher yields even in solvent-free processes. Thus, this heating mode provides a good alternative to the conventional heating by reducing time and energy consumption, hence reducing the costs and ecological impact of polymer chemistry and processing. This review states some achievements in the use of microwaves as energy source during the synthesis and transformation of polymers. Both in-solution and free-solvent processes are described at different scales, with comparison between microwave and conventional heating.
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Heriyadi, Bambang, Refky Adi Nata, Ardhymanto Am Tanjung, and Fadhilah. "The Impact of Microwave Treatment on the Andesite Rock Mechanical Properties." Journal of Physics: Conference Series 2582, no. 1 (September 1, 2023): 012023. http://dx.doi.org/10.1088/1742-6596/2582/1/012023.
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Abstract Alternate rock-breaking techniques to drilling and blasting could include using microwaves to break up rock masses. Drilling for blasting has a significant issue with the cost of drill bit replacement in a short time (weekly). The microwave-breaking technology could be a solution, but research is continuing. This research clarifies the proposed methods through a case study of PT. ATC is an andesite quarry that employs the drill-and-blast technique to break rock. This experiment replicates the previous study’s conclusion that rock strength decreases following microwave treatment on two rock strength tests involving the Point Load Index (PLI) and Schmidt Hammer (SH). The dynamic test (PUNDIT) result indicates that the p-wave velocity of microwaved samples is greater than that of non-microwaved samples (NMW). As a consequence of evaporation and mineral transformation within the rock, the density of the rock decreases, and the porosity increases.
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Kernou, Ourdia-Nouara, Amine Belbahi, Kenza Bedjaoui, Ghania Kaanin-Boudraa, Lila Boulekbache-Makhlouf, and Khodir Madani. "Inactivation of E. faecalis under microwave heat treatment and ultrasound probe." North African Journal of Food and Nutrition Research 7, no. 15 (March 20, 2023): 52–58. http://dx.doi.org/10.51745/najfnr.7.15.52-58.
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Background and aims: The Weibull model was fitted to survival curves in order to describe inactivation kinetics, and the effect of combined microwave (MW) and ultrasound (US) treatments was evaluated. Methods: Enterococcus faecalis ATCC 29212 present in 40 mL of sterile physiological water was treated with microwaves at 300W, 600W, and 900W and/or ultrasonic probes (amplitude 60 %, 80 % and 100 %, pulse (3s continuous, 3s discontinuous). Results: The use of an ultrasonic probe at 20 kHz displayed no significant impact on the patients' ability to survive. At 600 W and 300 W of MW treatment, a decrease of 3.96 log and 0.90 log, respectively, was obtained. Total destruction was accomplished in 70 seconds when 900 W of microwave therapy was used. Additionally, it was shown that the effectiveness of WM and US increased with increasing power and exposure duration. This was the case even when microwave or ultrasonic technology was utilized independently. In addition, the treatment that included both microwaves and ultrasound showed a significantly better effect than the treatment that only involved microwaves, but there were no significant differences between the coupled treatment and the microwave treatment given for 30 seconds. Conclusions: The results of the current study show that the inactivation of Enterococcus faecalis by ultrasound followed by microwave treatment was significantly higher than that obtained by microwave treatment followed by ultrasound. Keywords: Enterococcus faecalis, ultrasound, microwave, inactivation.
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Nilsson, Elna J. K., Tomas Hurtig, Andreas Ehn, and Christer Fureby. "Laminar Burning Velocity of Lean Methane/Air Flames under Pulsed Microwave Irradiation." Processes 9, no. 11 (November 19, 2021): 2076. http://dx.doi.org/10.3390/pr9112076.
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Laminar burning velocity of lean methane/air flames exposed to pulsed microwave irradiation is determined experimentally as part of an effort to accurately quantify the enhancement resulting from exposure of the flame to pulsed microwaves. The experimental setup consists of a heat flux burner mounted in a microwave cavity, where the microwave has an average power of up to 250 W at an E-field in the range of 350–380 kV/m. Laminar burning velocities for the investigated methane/air flames increase from 1.8 to 12.7% when exposed to microwaves. The magnitude of the enhancement is dependent on pulse sequence (duration and frequency) and the strength of the electric field. From the investigated pulse sequences, and at a constant E-field and average power, the largest effect on the flame is obtained for the longest pulse, namely 50 μs. The results presented in this work are, to the knowledge of the authors, the first direct determination of laminar burning velocity on a laminar stretch-free flame exposed to pulsed microwaves.
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Ozaki, Fumiyoshi, and Yutaka Okada. "Microwave-assisted Claisen Rearrangement of 1-Allyloxy-4-hydroxybenzene in the Presence of Metal Salt." Current Microwave Chemistry 8, no. 1 (July 13, 2021): 3–6. http://dx.doi.org/10.2174/2213335607666210106094449.
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Microwave-assisted Claisen rearrangement of allyloxybenzene with a hydroxyl group was conducted in the presence of metal salts. The rearrangement was promoted in the presence of an alkali metal salt, because the reaction substrate was converted into a phenoxide-type ion, which can efficiently absorb microwaves. In contrast, a Lewis acid was strongly coordinated to the ethereal oxygen, and this structure could also absorb microwaves efficiently.
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Rinkevich A. B., Perov D. V., Milyaev M. A., and Kuznetsov E. A. "Nonreciprocity of microwave propagation in the[(CoFe)/Cu]/(glass) system." Technical Physics 67, no. 12 (2022): 1672. http://dx.doi.org/10.21883/tp.2022.12.55204.189-22.
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The propagation of microwaves through the dielectric substrate/metal superlattice system [(CoFe)/Cu] has been investigated. The frequency dependences of transmission and reflection coefficients for the normal incidence of electromagnetic waves on the system in two opposite directions are measured. The effect of the substrate thickness on the magnitude of the microwave giant magnetoresistance effect during reflection and on nonreciprocity in the system is investigated. The influence of an external magnetic field on the nonreciprocity parameter is investigated. It has been established that under the conditions of nonreciprocity, the microwave giant magnetoresistance effect increases significantly when the wave is reflected. Keywords: metal superlattices, microwave giant magnetoresistance effect, microwaves, transmission and reflection coefficients, nonreciprocity.
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Danilchuk, Tatyana N., and Kamal М. Alkhateeb. "Effects of microwave radiation on living microorganisms: effects and mechanisms." Health, Food & Biotechnology 3, no. 1 (September 19, 2021): 75–84. http://dx.doi.org/10.36107/hfb.2021.i1.s107.
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The article analyzes the scientific literature on the effect of microwave exposure on the vital activity of microorganisms. The influence of the frequency of microwaves, the power of the applied impact and the total amount of absorbed energy on the viability of microorganisms and the features of their growth is considered. Possible mechanisms of interaction of microbial cells with the electromagnetic field in the ultrahigh frequency range are considered. It is noted that microorganisms die when exposed to high-energy and high-frequency microwaves, while low-energy and high-frequency microwaves contribute to the intensification of their growth. It is concluded that although many authors observe significant biological effects when exposed to microwaves on living systems, this issue has not been sufficiently studied in the scientific literature. It is of interest to conduct a systematic study of the effect of microwaves of a certain frequency on the biological, biochemical and growth parameters of the cells of microorganisms, in particular lactic acid organisms, in order to use the results of these studies in the food industry in the production of new food products.
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Ikeda, Y., J. K. Soriano, and N. Kawahara. "Plasma Formation And Its Sustainment In Time And Space In Microwave Enhanced Laser Induced Breakdown Spectroscopy." Proceedings of the International Symposium on the Application of Laser and Imaging Techniques to Fluid Mechanics 20 (July 11, 2022): 1–12. http://dx.doi.org/10.55037/lxlaser.20th.72.
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The transient and unstable plasma generation in the laser-induced breakdown is potentially resolved by the addition of microwaves. The laser and microwave technology combination extends the plasma lifetime and enhanced its emission intensity and volume. The expansion of the plasma started a few seconds after the initial formation of the plasma seed and the absorption of the microwave by the plasma also started to take effect. Large dome-shaped plasma is then briefly sustained until the end of the microwave duration. As the plasma expands, the plasma drifts away from the sample surface which is a good indication of the non-ablation effect of the microwave energy. The expansion of the plasma by microwaves enhances the breakdown of the plasma but potentially regulates the formation of toxic ablation fumes.
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Paduchowicz, P., M. Stachowicz, and K. Granat. "Effect of Microwave Heating on Moulding Sand Properties with Gypsum Binder." Archives of Foundry Engineering 17, no. 3 (September 1, 2017): 97–102. http://dx.doi.org/10.1515/afe-2017-0098.
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AbstractThe paper presents results of initial research on the possibility of applying microwave radiation in an innovative process of making casting moulds from silica sand, where gypsum CaSO4∙2H2O was acting as a binding material. In the research were compared strengths and technological properties of moulding mixture subjected to: natural bonding process at ambient temperature or natural curing with additional microwave drying or heating with the use of microwaves immediately after samples were formed. Used in the research moulding sands, in which dry constituents i.e. sand matrix and gypsum were mixed in the ratio: 89/11. On the basis of the results of strength tests which were obtained by various curing methods, beneficial effect of using microwaves at 2.45 GHz for drying up was observed after 1, 2 and 5 hours since moisture sandmix was formed. Applying the microwaves for hardening just after forming the samples guarantees satisfactory results in the obtained mechanical parameters. In addition, it has been noted that, from a technological and economic point of view, drying the silica sand with gypsum binder in microwave field can be an alternative to traditional molding sand technologies.
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Kovtun, Yu V., Y. V. Syusko, E. I. Skibenko, and A. I. Skibenko. "Experimental Study of Inhomogeneous Reflex-Discharge Plasma Using Microwave Refraction Interferometry." Ukrainian Journal of Physics 63, no. 12 (December 9, 2018): 1057. http://dx.doi.org/10.15407/ujpe63.12.1057.
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The phase shift at the plasma interferometry with oblique microwaves and microwaves passing through the center of a plasma formation has been calculated. The critical density Ncr and the critical radius rcr of a plasma layer, at which microwaves do not hit the horn antenna, are calculated for various radial plasma distribution functions. The time dependences of the phase shift for the transverse and oblique probing modes are experimentally measured. Using the phase shifts determined by the both methods, the time dependence of the product NpL of the electron concentration in plasma and the optical path length of a microwave beam in vacuum is found, and the average plasma density is estimated.
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Aldhaeebi, Maged A., Khawla Alzoubi, Thamer S. Almoneef, Saeed M. Bamatraf, Hussein Attia, and Omar M. Ramahi. "Review of Microwaves Techniques for Breast Cancer Detection." Sensors 20, no. 8 (April 22, 2020): 2390. http://dx.doi.org/10.3390/s20082390.
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Conventional breast cancer detection techniques including X-ray mammography, magnetic resonance imaging, and ultrasound scanning suffer from shortcomings such as excessive cost, harmful radiation, and inconveniences to the patients. These challenges motivated researchers to investigate alternative methods including the use of microwaves. This article focuses on reviewing the background of microwave techniques for breast tumour detection. In particular, this study reviews the recent advancements in active microwave imaging, namely microwave tomography and radar-based techniques. The main objective of this paper is to provide researchers and physicians with an overview of the principles, techniques, and fundamental challenges associated with microwave imaging for breast cancer detection. Furthermore, this study aims to shed light on the fact that until today, there are very few commercially available and cost-effective microwave-based systems for breast cancer imaging or detection. This conclusion is not intended to imply the inefficacy of microwaves for breast cancer detection, but rather to encourage a healthy debate on why a commercially available system has yet to be made available despite almost 30 years of intensive research.
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Lin, J. C. "Hearing microwaves: the microwave auditory phenomenon." IEEE Antennas and Propagation Magazine 43, no. 6 (2001): 166–68. http://dx.doi.org/10.1109/74.979546.
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Damasari, Arita. "PEMANFAATAN GELOMBANG MIKRO PADA EKSTRAKSI BUAH." Agritech: Jurnal Fakultas Pertanian Universitas Muhammadiyah Purwokerto 24, no. 1 (June 28, 2022): 109. http://dx.doi.org/10.30595/agritech.v24i1.13654.
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One of the preparations of Agrotechnology is a fruit. Fruit can be processed with non-conventional techniques by utilizing microwave technology. This study aims to analyze the use of microwaves in fruit extraction. Research methods are qualitative methods with Case Studies. Data collected by data analysis method by reducing, presenting and drawing conclusions. The results showed that the greater the temperature, power, and solvent ratio will produce fruit extraction with high levels of pectin. The solvent used is a kind of ethanol. Fruit extraction with Microwaved Assisted extraction is able to be a fast and efficient solution in producing high quality fruit extraction levels compared to processing in the traditional way.
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Antoniou, Nicholas. "Scanning Microwave Impedance Microscopy: Overview and Low Temperature Operation." EDFA Technical Articles 25, no. 1 (February 1, 2023): 9–13. http://dx.doi.org/10.31399/asm.edfa.2023-1.p009.
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Gartshore, Alexandra, Matt Kidd, and Lovleen Tina Joshi. "Applications of Microwave Energy in Medicine." Biosensors 11, no. 4 (March 26, 2021): 96. http://dx.doi.org/10.3390/bios11040096.
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Microwaves are a highly utilized electromagnetic wave, used across a range of industries including food processing, communications, in the development of novel medical treatments and biosensor diagnostics. Microwaves have known thermal interactions and theorized non-thermal interactions with living matter; however, there is significant debate as to the mechanisms of action behind these interactions and the potential benefits and limitations of their use. This review summarizes the current knowledge surrounding the implementation of microwave technologies within the medical industry.
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Adhiksana, Arief, and Kusyanto. "PENGARUH JUMLAH PELARUT PADA PROSES EKSTRAKSI MINYAK KAYU CENGKEH MENGGUNAKAN MICROWAVE." Journal of Research and Technology 1, no. 1 (December 30, 2015): 30–34. http://dx.doi.org/10.55732/jrt.v1i1.328.
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Clove oil is usually produced from the leaves and flowers, while the twigs cloves actually have potential to be exploited. One of the latest methods that can be used is the microwave assisted extraction. The advantages of microwaves is its ability to deliver energy directly to all material, so it can save time compared to conventional extraction methods. This research aims to study the effect of solvents on the extraction using microwaves. The solvent is water because the polar so very good at absorbing microwave. The variables studied were the weight (75-150 grams) and volume of solvent (400-500 ml) , while the microwave power of 264 W. The choice of wood clove oil yield was obtained of 3.89 % on the amount of solvent to 500 ml with weight is 150 grams.
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MOTALLEBI, Ahad. "Effect of microwave radiation on seed viability, survival of Aspergillus niger van Tieghem and oil quality of oilseeds crops canola, soybean and safflower." Acta agriculturae Slovenica 107, no. 1 (April 6, 2016): 73. http://dx.doi.org/10.14720/aas.2016.107.1.08.
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The effect of microwave's radiation on seed viability of three different oilseed crops, spores of <em>Aspergillus niger </em>and quality of extracted oil from treated seeds over various exposure times was evaluated. The seeds were exposed to 2450 MHz. at five different power levels of 0, 100, 200, 400, 600 and 800 W for two exposure times of three and five minutes. At a given time, a direct negative relationship between seed viability and microwave's radiation power level was detected. Substantial variation in the lethality of tested seeds to microwave's power levels was apparent in the fiducial limits of the estimated LD<sub>50 </sub>values in probit analysis approach. A similar trend of <em>A. niger</em> spores’ susceptibility to microwave radiation was detected. The microwaves' radiation and exposure time did not impact one another and a significant interaction was not detected. Short term fungal infection did not cause substantial quantitative and qualitative damage to the oilseeds. The oil quality was generally unaffected by microwave radiation and fungal infestation for tested oilseeds. Moreover, microwave radiation decreased seed germination percentage and vigor index. The microwave radiation could provide an effective and friendly environmental treatment technique for improving the dietary consumption of the oil in any seed disinfestation program.
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McArdle, Phillip. "Microwave Myths and Tissue Processing." Microscopy Today 15, no. 1 (January 2007): 14–17. http://dx.doi.org/10.1017/s1551929500051129.
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Microwave-assisted preparation of histological samples has been performed for decades; what began with a few pioneering researchers has now become a routine and accepted practice in many clinical and research laboratories. Reliable, reproducible microwave protocols have been developed for a variety of operations: LM and EM processing, decalcification, fixation, special stains, antigen retrieval and more. Laboratories employing microwave procedures often do so for several compelling reasons: in addition to the expected time savings (often on the scale of orders of magnitude), improved morphology, retained immunoreactivity, and the elimination of hazardous reagents are benefits typically realized as well.Despite the increasing availability of laboratory microwaves, consumer-grade (“kitchen”) microwaves continue to be used, almost invariably due to cost considerations. (EBS has maintained since 1992 that a kitchen microwave has no place in the lab.) At any time in the US there are hundreds of microwave models to choose from: a dizzying array of sizes, wattages, options, and configurations await the shopper.