Journal articles on the topic 'Microwave'
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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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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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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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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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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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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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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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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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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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Liu, Ya Jing, Tao Jiang, Zhi Deng, Xiang Xin Xue, and Pei Ning Duan. "Stuy on Microwave-Assisted Grinding of Low-Grade Ludwigite." Materials Science Forum 814 (March 2015): 214–19. http://dx.doi.org/10.4028/www.scientific.net/msf.814.214.
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The low-grade ludwigite is one of the complex and refractory ores. Based on the high energy consumption and inefficient in the grinding process and according to the microwave-assisted grinding principle, this paper studied the microwave absorption property of ludwigite and researched the effect of microwave heating on the grinding efficiency of it. The non-microwaved and microwaved samples were characterized with regard to the chemical components, mineral compositions, macroscopic structure and microstructure, grinding efficiency by methods of the chemical analysis, X-ray diffraction (XRD), scanning electron microscopy (SEM) and grain size analysis, etc. The results indicated that ludwigite, with good microwave absorption property, was suitable for microwave processing. The grindability of microwaved ludwigite was related to the microwave power and microwave heating temperature. By the microwave heating temperature attained 500~650°C, many macro-cracks and micro-cracks were produced by thermal stress between different mineral interfaces, which resulted in the decrease of strength of ludwigite and easy levigation, but the mineral compositions had no obviously changed, which would not affect the subsequent magnetic separation. It was concluded that short, high-power treatments were most effective but over-exposure of the sample led to reductions in efficiency. Under the same conditions, the grinding efficiency of ludwigite was improved 24.54% higher than untreated ore, which significantly improved the grinding efficiency and reduced energy consumption.
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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.
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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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Sun, Xiaohe, Changyuan Zhai, Shuo Yang, Haolin Ma, and Chunjiang Zhao. "Simulations and Experiments of the Soil Temperature Distribution after 2.45-GHz Short-Time Term Microwave Treatment." Agriculture 11, no. 10 (September 27, 2021): 933. http://dx.doi.org/10.3390/agriculture11100933.
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Microwave treatment is a green and pollution-free soil disinfection method. The application of microwaves to disinfect soil before cultivation is highly important to increase crop yields and protect the ecological environment. The electromagnetic field is an important parameter influencing the soil temperature field in the process of microwave soil treatment, and the change in soil temperature directly affects soil disinfection. Therefore, this article carried out research on the heating pattern in North China loess due to microwave treatment. First, COMSOL software was employed to simulate the microwave soil treatment process to analyze microwave penetration into soil. Second, with the application of microwaves at the designed frequency produced with a 2.45-GHz tunable microwave generating microdevice, soil with water contents of 0%, 10%, 20%, and 30% was treated for 10~60 s (at 10-s time intervals), and experiments on the influence of the microwave output power, treatment time, and soil moisture content on the soil temperature were performed via the controlled variable method. The simulation results indicate that with increasing soil moisture content, the microwave frequency inside the soil model increases, and the electric field intensity value decreases in the model at the same depth. After microwaves traverse through the 20-cm soil model, the incident field strength is three orders of magnitude lower than the outgoing field strength. The results of the microwave soil treatment experiment reveal that: (1) Compared to microwave output power levels of 1.8 and 1.6 kW, a level of 2 kW is more suitable for microwave soil disinfection. (2) After treatment, the highest temperature occurs on the soil surface, not within the soil. (3) The location of the highest soil internal temperature after microwave treatment increasingly approaches the soil surface with increasing soil moisture content, and the microwave output power does not affect the location of the highest soil internal temperature. Combining the electromagnetic field simulation and microwave soil treatment experiment results, it was found that the higher the field strength is, the higher the temperature value, and the highest soil internal temperature after microwave treatment often occurs at the first electromagnetic wave peak.
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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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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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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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Aherrao, Disha Sunil, Charanjeet Singh, and A. K. Srivastava. "Review of ferrite-based microwave-absorbing materials: Origin, synthesis, morphological effects, dielectric/magnetic properties, composites, absorption mechanisms, and optimization." Journal of Applied Physics 132, no. 24 (December 28, 2022): 240701. http://dx.doi.org/10.1063/5.0123263.
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With the advancement and up-gradation of wireless technology, people worldwide are surrounded by microwaves, however, with the brighter side comes the darker side too. These microwave/electromagnetic wireless signals interfere with the environment/mankind and are referred to as electromagnetic interference (EMI)/electromagnetic or microwave pollution. Microwave/electromagnetic absorbers are used to mitigate this EMI or electromagnetic pollution. Researchers have been working on microwave absorbents of different kinds to save humans, their gadgets, electronically printed cards, etc. to create a healthy and radiation-free environment. Recently, there is an advancement in different forms of ferrite absorbers. This review presents a description of what are ferrite-based microwave absorbers, the preparation method of absorbers, the working principle, and detailed insights involving necessary models and mechanisms regarding microwave absorption. It also encapsulates the description of how the ferrite composition, morphology, doping, reflection loss peaks, and matrix account for optimizing the performance of the absorbers. The history, origin, and ancestral use of microwave absorbers are mentioned, and how technological needs lead to advancement in ferrite microwave absorbers has also been discussed. A picture is portrayed of what are microwaves, their potential hazards, and how these hazards should be taken care of with the help of ferrite microwave absorbers.
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Fear, Elise C. "Microwave Imaging of the Breast." Technology in Cancer Research & Treatment 4, no. 1 (February 2005): 69–82. http://dx.doi.org/10.1177/153303460500400110.
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Microwave imaging for medical applications has been of interest for many years. Recently, microwave imaging for breast cancer detection has gained attention due to advances in imaging algorithms, microwave hardware and computational power. The breast is relatively translucent to microwaves, accessible for imaging, and there appears to be a significant electromagnetic property contrast between tumors and healthy tissues. Therefore, breast imaging may be the first clinically viable application of microwave imaging. This paper reviews recent developments in passive, hybrid, and active approaches to microwave breast cancer detection.
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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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Aparicio-Lopez, Cesar B. "Abstract 5747: Microwave responsive thermosensitive lipid nanoparticles for spatiotemporal delivery of chemotherapeutics." Cancer Research 84, no. 6_Supplement (March 22, 2024): 5747. http://dx.doi.org/10.1158/1538-7445.am2024-5747.
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Abstract Pancreatic cancer is a highly lethal malignancy with an urge for the exploration of novel treatments. One promising approach is microwaved-induced hyperthermia, which has shown great antitumor and synergistic effects when combined with other therapies. The application of microwaves produces heat by dielectric hysteresis which depends on the dielectric properties of molecules. Ionic liquids (ILs) are compounds composed of ions with <100 °C melting point and have strong dielectric properties. In short, we propose the creation of microwave-sensitive nanoparticles using IL, enabling precise hyperthermia induction with low-powered microwaves in localized areas. To achieve this, we stabilize a core composed of 1-butyl-methylimidazolium bromide or 1-butyl-3-methylimidazolium hexafluorophosphate using Span 80, Tween 20, and Triton-X as surfactants, along with phosphatidylcholine lipids as “cosurfactants”. Employing a double emulsion procedure for fabrication, nanoparticles are characterized using dynamic light scattering, Fourier-transform infrared spectroscopy, and transmission electron microscopy. Furthermore, we assess microwave sensitivity by comparing thermal changes between liposomes loaded with 120 mM and 250 mM NaCl solutions. Subsequently, we evaluate biocompatibility and heat effects by incubating IL nanoparticles with BXPC3 and KPC cells, monitoring cell viability through MTT assays. We aim to confine the ILs within the nanoparticle core rather than incorporating them into the membrane. We anticipate increased microwave sensitivity, translating to reduced off-target effects and enhanced precision in hyperthermia treatment. This research holds promise for improving the therapeutic outcomes of pancreatic cancer treatment. Citation Format: Cesar B. Aparicio-Lopez. Microwave responsive thermosensitive lipid nanoparticles for spatiotemporal delivery of chemotherapeutics [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5747.
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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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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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Slap, Steven E. "The Function of a Water Logd in A Laboratory Microwave." Microscopy Today 6, no. 9 (November 1998): 3–4. http://dx.doi.org/10.1017/s1551929500069431.
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There are three ways that objects can react to microwave energy within a microwave cavity:1.They can absorb microwave enengy. This is the case with all polar molecules (substances with positive and negative ionic poles). Examples include water, alcohols and biological specimens. Objects which absorb microwave energy will get hot as a result. The total amount of microwave absorbing material within the miaowave cavity is called the “load.”2.They can reflect microwaves. This is the case with metals. The function of the medal walls which make up a microwave cavity is to keep the microwave energy within the cavity. The metal walls themselves will not get hot.3.They can be “microwave-transparent.” This is the case with many non-polar molecules, such as paraffin and many plastics. Objects which ane microwave transpanent will heet very poorly in a microwave.
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Buchelnikov, Vasiliy D., D. V. Lousguine-Luzgin, Igor V. Bychkov, and A. P. Anzulevich. "Microwave Heating of Metallic Powders." Solid State Phenomena 152-153 (April 2009): 385–88. http://dx.doi.org/10.4028/www.scientific.net/ssp.152-153.385.
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It is known from experimental data that bulk metallic samples reflect microwaves while powdered samples can absorb such radiation and be heated efficiently. In the present paper we investigate theoretically the mechanisms of penetration of microwave radiation through a layer of metallic powder and microwave heating of such system.
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Palma, Vincenzo, Daniela Barba, Marta Cortese, Marco Martino, Simona Renda, and Eugenio Meloni. "Microwaves and Heterogeneous Catalysis: A Review on Selected Catalytic Processes." Catalysts 10, no. 2 (February 18, 2020): 246. http://dx.doi.org/10.3390/catal10020246.
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Since the late 1980s, the scientific community has been attracted to microwave energy as an alternative method of heating, due to the advantages that this technology offers over conventional heating technologies. In fact, differently from these, the microwave heating mechanism is a volumetric process in which heat is generated within the material itself, and, consequently, it can be very rapid and selective. In this way, the microwave-susceptible material can absorb the energy embodied in the microwaves. Application of the microwave heating technique to a chemical process can lead to both a reduction in processing time as well as an increase in the production rate, which is obtained by enhancing the chemical reactions and results in energy saving. The synthesis and sintering of materials by means of microwave radiation has been used for more than 20 years, while, future challenges will be, among others, the development of processes that achieve lower greenhouse gas (e.g., CO2) emissions and discover novel energy-saving catalyzed reactions. A natural choice in such efforts would be the combination of catalysis and microwave radiation. The main aim of this review is to give an overview of microwave applications in the heterogeneous catalysis, including the preparation of catalysts, as well as explore some selected microwave assisted catalytic reactions. The review is divided into three principal topics: (i) introduction to microwave chemistry and microwave materials processing; (ii) description of the loss mechanisms and microwave-specific effects in heterogeneous catalysis; and (iii) applications of microwaves in some selected chemical processes, including the preparation of heterogeneous catalysts.
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Wang, Kai, Bai-Ke Lin, You-Jian Song, Fei Meng, Yi-Ge Lin, Shi-Ying Cao, Ming-Lie Hu, and Zhan-Jun Fang. "Low-noise microwave generation based on optical-microwave synchronization." Acta Physica Sinica 71, no. 4 (2022): 044204. http://dx.doi.org/10.7498/aps.71.20211253.
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Low-noise microwave signals are of vital importance in fields such as cold atomic optical clocks, photon radars, and remote synchronization at large facilities. Here, we report a compact all-optical-fiber method to generate a low noise microwave signal, in which the fiber loop optical-microwave phase detector is used to coherently transfer the frequency stability of the ultra-stable laser to the microwave. Combining a narrow linewidth optical frequency comb and a fiber loop optical-microwave phase discriminator, a tight phase-lock between 7 GHz dielectric oscillator and optical frequency comb is achieved, the remaining phase noise of the synchronized optical pulse sequence and the microwave signal is –100 dBc/Hz@1 Hz, and the timing jitter is 8.6 fs (1 Hz—1.5 MHz); by building two sets of low-noise microwave generation systems, the measured residual phase noise of the 7 GHz microwave is –90 dBc/Hz@1 Hz, and the corresponding frequency stability is 4.8 × 10<sup>–15</sup>@1 s. These results provide a novel idea for generating the low-noise microwaves based on optical coherent frequency division.
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YANG, WEN-JEI, SADANARI MOCHIZUKI, and PAUL P. T. YANG. "APPLICATIONS OF MICROWAVE RADIATION IN MEDICINE." Journal of Mechanics in Medicine and Biology 02, no. 01 (March 2002): 53–63. http://dx.doi.org/10.1142/s0219519402000162.
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This paper presents major medical applications of microwave radiation in therapy and diagnostics of disorders of thermoregulation, especially hyperthermia and thermography. Microwave thermography is a thermal imaging system produced by self-emission, using emissivity differences to extend our vision beyond the shortwave red. Human tissues are partially transparent to microwaves, thus it is possible to detect the microwave of subcutaneous tissues in thermography, and to allow microwave energy penetration through subcutaneous tissues for deep-tissue heating in hyperthermia. The physics of microwave thermography together with the microwave properties and emission of body tissues are introduced. It is followed by reviews of the literature pertinent to microwave hyperthermia in therapy and treatment. Recent development in this field is briefly discussed.
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Schichnes, Denise, Jeffrey A. Nemson, and Steven E. Ruzin. "Microwave Protocols for Plant and Animal Paraffin Microtechnique." Microscopy Today 13, no. 3 (May 2005): 50–53. http://dx.doi.org/10.1017/s1551929500051658.
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The microwave oven is a valuable tool for light and electron microscopy microtechnique labs. Tissue processing times, traditionally taking up to two weeks, have been reduced to a few hours as a result of the implementation of microwave technology (Kok et al., 1988, Gibberson and Demaree, 2001). In addition, the quality of the tissue preparations has improved dramatically. Microwave ovens have also evolved since their first use in the laboratory. Early experiments were conducted using relatively crude commercial microwave ovens. Now, labs use microwave ovens with temperature probes, strict control over the magnetron (which generates the microwaves), variable power supplies, chamber cooling, and high microwave field uniformity.
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Ausania, F., R. Carracedo Iglesias, and M. Casal Rivas. "Microwave liver ablation and dark urine." Annals of The Royal College of Surgeons of England 96, no. 4 (May 2014): e1-e3. http://dx.doi.org/10.1308/003588414x13814021679870.
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Microwave assisted liver resection is a useful technique, especially when haemostasis could be difficult to achieve with conventional methods. However, prolonged administration of microwaves can be responsible for intraoperative haemoglobinuria. We describe the first case of acute haemolysis secondary to microwave assisted liver resection.
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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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Gopalakrishnan, Keerthy, Aakriti Adhikari, Namratha Pallipamu, Mansunderbir Singh, Tasin Nusrat, Sunil Gaddam, Poulami Samaddar, et al. "Applications of Microwaves in Medicine Leveraging Artificial Intelligence: Future Perspectives." Electronics 12, no. 5 (February 23, 2023): 1101. http://dx.doi.org/10.3390/electronics12051101.
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Microwaves are non-ionizing electromagnetic radiation with waves of electrical and magnetic energy transmitted at different frequencies. They are widely used in various industries, including the food industry, telecommunications, weather forecasting, and in the field of medicine. Microwave applications in medicine are relatively a new field of growing interest, with a significant trend in healthcare research and development. The first application of microwaves in medicine dates to the 1980s in the treatment of cancer via ablation therapy; since then, their applications have been expanded. Significant advances have been made in reconstructing microwave data for imaging and sensing applications in the field of healthcare. Artificial intelligence (AI)-enabled microwave systems can be developed to augment healthcare, including clinical decision making, guiding treatment, and increasing resource-efficient facilities. An overview of recent developments in several areas of microwave applications in medicine, namely microwave imaging, dielectric spectroscopy for tissue classification, molecular diagnostics, telemetry, biohazard waste management, diagnostic pathology, biomedical sensor design, drug delivery, ablation treatment, and radiometry, are summarized. In this contribution, we outline the current literature regarding microwave applications and trends across the medical industry and how it sets a platform for creating AI-based microwave solutions for future advancements from both clinical and technical aspects to enhance patient care.
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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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Ren, Yuqing, Yao Chen, Qinyu Li, Hexing Li, and Zhenfeng Bian. "Microwave-Assisted Photocatalytic Degradation of Organic Pollutants via CNTs/TiO2." Catalysts 12, no. 9 (August 24, 2022): 940. http://dx.doi.org/10.3390/catal12090940.
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Introducing microwave fields into photocatalytic technology is a promising strategy to suppress the recombination of photogenerated charge carriers. Here, a series of microwave-absorbing photocatalysts, xCNTs/TiO2, were prepared by combining titanium dioxide (TiO2) with carbon nanotubes (CNTs) using a typical alcoholic thermal method to study the promotion of microwave-generated thermal and athermal effects on the photocatalytic oxidation process. As good carriers that are capable of absorbing microwaves and conducting electrons, CNTs can form hot spots and defects under the action of the thermal effect from microwaves to capture electrons generated on the surface of TiO2 and enhance the separation efficiency of photogenerated electrons (e−) and holes (h+). Excluding the influence of the reaction temperature, the athermal effect of the microwave field had a polarizing effect on the catalyst, which improved the light absorption rate of the catalyst. Moreover, microwave radiation also promoted the activation of oxygen molecules and hydroxyl groups on the catalyst surface to generate more reactive oxygen radicals. According to the mechanism analysis, the microwave effect significantly improved the photocatalytic advanced oxidation process, which lays a solid theoretical foundation for practical application.
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Abdullah, Iram. "Manufacturing of Kevlar/Polyester Composite by Resin Transfer Moulding using Conventional and Microwave Heating." Pakistan Journal of Scientific & Industrial Research Series A: Physical Sciences 58, no. 1 (April 27, 2015): 34–40. http://dx.doi.org/10.52763/pjsir.phys.sci.58.1.2015.34.40.
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Microwave heating was incorporated into the resin transfer moulding technique. Polytetrafluoroethylene (PTFE) mould was used to cure the composite panel. Through the use of microwave heating, the mechanical and physical properties of produced Kevlar fibre/polyester composites were compared to those manufactured by conventional resin transfer moulding. The flexural modulus and flexural strength of 6-ply conventionally cured composites was 45% and 9% higher than the flexural modulus and flexural strength of 6-ply microwaved cured composites, respectively. However, 19% increase in interlaminar shear strength (ILSS) and 2% increase in compressive strength was observed in 6-ply microwave cured composites. This enhancement in ILSS and compressive strength is attributed to the better interfacial bonding of polyester resin with Kevlar fibres in microwaved cured composite, which was also confirmed via electron microscopy scanning. Furthermore, the microwave cured composite yielded maximum void contents (3%).
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Shukla, A. K., A. Mondal, and A. Upadhyaya. "Numerical modeling of microwave heating." Science of Sintering 42, no. 1 (2010): 99–124. http://dx.doi.org/10.2298/sos1001099s.
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The present study compares the temperature distribution within cylindrical samples heated in microwave furnace with those achieved in radiatively-heated (conventional) furnace. Using a two-dimensional finite difference approach the thermal profiles were simulated for cylinders of varying radii (0.65, 6.5, and 65 cm) and physical properties. The influence of susceptor-assisted microwave heating was also modeled for the same. The simulation results reveal differences in the heating behavior of samples in microwaves. The efficacy of microwave heating depends on the sample size and its thermal conductivity.
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Ma, Yulin, Yao Cheng, Wenlong Shang, Dong Zhao, and Xianggang Duan. "Experimental Study on Coal Permeability Variation during Microwave Radiation." Advances in Materials Science and Engineering 2020 (February 24, 2020): 1–18. http://dx.doi.org/10.1155/2020/7270185.
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Coal-bed methane (CBM) is a new type of clean energy, which is abundant in China. Rational development and use of CBM can not only reduce the occurrence of mine disasters but also alleviate energy shortages. However, the “high storage capacity and low-permeability” characteristics of China’s CBM have hindered the realization of industrialized CBM production. To study the effect of microwave radiation on the permeability of coal reservoirs, a seepage experiment under different stress and microwave radiation conditions was carried out by using the seepage experiment system of gas-bearing coal under microwave radiation developed by the authors. The relationship among different microwave powers, different irradiation times, different energy inputs, and coal permeability was explored. The results show that the microwave power effect and the temperature effect promote coal permeability. Under microwave radiation, the relationship between permeability and effective stress followed a negative exponential function, and all R-squared values were greater than 0.97. The permeability increased monotonically with increasing microwave power and irradiation time, and the linear fitting slope of the rate of increase in the low-effective-stress area was greater than in the high-effective-stress area. Under the same energy input, permeability increased with rising microwave power. The peak temperature of the coal sample also increased with increasing power. When the microwave power increased to a certain range, the permeability growth of the coal sample was the greatest, and the temperature gradient of the coal-sample temperature field was the steepest. The coal sample experienced the optimum microwave radiation power under the action of microwaves to achieve the permeability enhancement effect of microwaves on the coal sample. The experimental results provide a theoretical reference for applying microwave radiation technology in coal-bed methane extraction.
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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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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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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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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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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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MONTEIRO, Rafael Jordão Storino Vaz, Bárbara Daphini Matos SILVA, Lorena Esteves SILVEIRA, Maria Eugênia ALVAREZ-LEITE, Flavio Ricardo MANZI, and Cláudia Valéria de Sousa Resende PENIDO. "Microwave and autoclave usage in human teeth sterilization." RGO - Revista Gaúcha de Odontologia 66, no. 4 (December 2018): 317–20. http://dx.doi.org/10.1590/1981-863720180004000043437.
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ABSTRACT Objective: evaluate the sterilization of human teeth irradiated by microwaves. Methods: Sixty human third molars are divided into three groups (n = 20): G1 without sterilization (negative control); G2 - autoclaving for 20 minutes 1Kgf/cm2 at 120 ° C (positive control); G3 - sterilization in a microwave vessel containing 200ml of distilled water in a microwave irradiated at 650W for 3 minutes. Results: No culture media of G2 and G3 presented contamination after autoclaving and microwave sterilization. Conclusion: Autoclave sterilization and microwave sterilization were effective decontamination methods under the experimental conditions tested.
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Chen, Chi, Wenjie Fu, Chaoyang Zhang, Dun Lu, Meng Han, and Yang Yan. "Dual-Frequency Microwave Plasma Source Based on Microwave Coaxial Transmission Line." Applied Sciences 11, no. 21 (October 22, 2021): 9873. http://dx.doi.org/10.3390/app11219873.
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A dual-frequency plasma source has many advantages in applications. In this paper, a dual-frequency microwave plasma source is presented. This microwave plasma source is based on a coaxial transmission line without the resonator, and it can be operated in a wide band frequency region. Two microwaves are inputted from two ports into the plasma reactor: one is used firstly to excite the plasma and the other one is used to adjust plasma characteristics. Based on the COMSOL Multiphysics simulation, the experiment is carried out. In the experimental investigation, the plasma electron density and electron temperature can be controlled, respectively, by feeding in different frequencies from the second port, causing the particles at different energy levels to present different frequencies. This exploratory research improves the operation frequency of dual-frequency microwave plasma sources from RF to microwave.
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Sellgren, Katelyn L., Christopher W. Gregory, Ethan J. D. Klem, Jeffrey R. Piascik, and Brian R. Stoner. "Microwave disinfection as a treatment for blackwater from dewatered sludge." Gates Open Research 2 (March 23, 2018): 16. http://dx.doi.org/10.12688/gatesopenres.12801.1.
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Background: Fast and efficient on-site treatment of blackwater, rejected from the dewatering process, can decrease the costs associated with disposal of fecal sludge removed from pit latrines by reducing the volume of sludge transported to the disposal site.Methods: In this study, we examine the potential use of low cost consumer microwave units for disinfecting pathogen-rich blackwater. Domestic bench top microwave units were modified to allow flow through and re-circulation of blackwater. Energy, throughput, and disinfection characteristics related to microwaves are studied and compared to conventional thermal heating. A custom flow through stack of 5 microwaves was designed and used to examine the feasibility of single pass, high throughput application.Results and Conclusions: The results show microwave energy does not play a role in the disinfection of blackwater. The benefits of a microwave disinfection system are shown to be high energy efficiency, compact size, and cost efficiency.
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Wagh, Yogesh B., and Dipak S. Dalal. "Microwave-Assisted Domino Cyclization Reactions." Current Microwave Chemistry 8, no. 3 (December 2021): 140–72. http://dx.doi.org/10.2174/2213335608666211006121803.
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Background: Microwave-assisted domino cyclization reactions have attracted great interest for researchers to synthesize complex compounds in shorter times with increased yields. The domino reactions were used in various synthetic approaches and many drug deliveries in medicinal chemistry with microwave-assisted approaches. Methods: Microwave irradiation has been applied for various domino reactions. The research related to microwave-assisted domino cyclization was reviewed and the important methodologies were collected from 2011-2021. Results: Only those methodologies that involve microwave-assisted domino cyclization reactions during synthesis in a related manner have been reviewed. Along with some recent syntheses that are microwave-assisted regarding new heterocyclic moieties are summarized. Conclusion: Microwave-assisted domino cyclization reactions can be employed to quickly explore and increase molecular diversity in synthetic chemistry. We hope that this review will be helpful to find out complex molecule synthesis by microwave-assisted domino cyclization reactions. This review aimed to explain the applications of microwaves for the domino reactions from 2011- 2021. In this respect, microwave-mediated methods help researchers to make helpful studies.
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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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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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Sakemi, Daisuke, Nick Serpone, and Satoshi Horikoshi. "Search for the Microwave Nonthermal Effect in Microwave Chemistry: Synthesis of the Heptyl Butanoate Ester with Microwave Selective Heating of a Sulfonated Activated Carbon Catalyst." Catalysts 11, no. 4 (April 2, 2021): 466. http://dx.doi.org/10.3390/catal11040466.
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The heptyl butanoate ester was synthesized from butanoic acid and heptanol in a heterogeneous medium in the presence of sulfonated activated carbon (AC-SO3H) catalyst particles subjected to microwave irradiation, which led to higher conversion yields (greater product yields) than conventional heating with an oil bath. The advantage of the microwaves appeared only when the moisture content in the butanoic acid batch(es) was high, suggesting that, unlike conventional heating, the reverse reaction caused by the moisture content and/or by the byproduct water was suppressed by the microwaves. This contrasted with the results that were found when carrying out the reaction in a homogeneous medium in the presence of the 2,4,6-trimethylpyridinium-p-toluene sulfonate (TMP-PTS) catalyst, as product yields were not improved by microwave heating relative to conventional heating. The removal of moisture/water content in the reaction solution was more pronounced when the reactor was cooled, as the reaction yields were enhanced via selective heating of the heterogeneous catalyst. A coupled electromagnetic field/heat transfer analysis gave credence to the selective heating of the AC-SO3H catalyst, which was further enhanced by cooling the reactor. It was deduced that unforeseen impurities and local high-temperature fields generated on the surface of small fine catalyst particles may have had an effect on the microwave chemistry such that the associated phenomena could be mistaken as originating from a nonthermal effect of the microwaves. Accordingly, it is highly recommended that impurities and selective heating be taken into consideration when examining and concluding the occurrence of a microwave nonthermal effect.
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Zhu, Wenhe, Yan Cui, Xianmin Feng, Yan Li, Wei Zhang, Junjie Xu, Huiyan Wang, and Shijie Lv. "The apoptotic effect and the plausible mechanism of microwave radiation on rat myocardial cells." Canadian Journal of Physiology and Pharmacology 94, no. 8 (August 2016): 849–57. http://dx.doi.org/10.1139/cjpp-2015-0537.
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Microwaves may exert adverse biological effects on the cardiovascular system at the integrated system and cellular levels. However, the mechanism underlying such effects remains poorly understood. Here, we report a previously uncharacterized mechanism through which microwaves damage myocardial cells. Rats were treated with 2450 MHz microwave radiation at 50, 100, 150, or 200 mW/cm2 for 6 min. Microwave treatment significantly enhanced the levels of various enzymes in serum. In addition, it increased the malondialdehyde content while decreasing the levels of antioxidative stress enzymes, activities of enzyme complexes I–IV, and ATP in myocardial tissues. Notably, irradiated myocardial cells exhibited structural damage and underwent apoptosis. Furthermore, Western blot analysis revealed significant changes in expression levels of proteins involved in oxidative stress regulation and apoptotic signaling pathways, indicating that microwave irradiation could induce myocardial cell apoptosis by interfering with oxidative stress and cardiac energy metabolism. Our findings provide useful insights into the mechanism of microwave-induced damage to the cardiovascular system.
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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.
Full textAbstract:
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.