Zeitschriftenartikel: „Microwave ovens – Scientific applications“

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Arslan, Derya, M. Kürşat Demir, Ayşenur Acar und Fatma Nur Arslan. „Investigation of Wheat Germ and Oil Characteristics with Regard to Different Stabilization Techniques“. Food Technology and Biotechnology 58, Nr. 3 (28.09.2020): 348–55. http://dx.doi.org/10.17113/ftb.58.03.20.6638.

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Research background. Utilization of wheat germ (WG) and wheat germ oil (WGO) is limited due to high enzymatic activity and unsaturated fatty acids and therefore stabilization techniques are needed to overcome this problem. Experimental approach. In this study, the effects of stabilization methods (dry convective oven heating at 90 and 160 oC and microwave radiation under 180 W and 360 W output power, and steaming by autoclave) on both WG and WGO were evaluated. Results and conclusions. Steaming caused the most dramatic changes on lipoxygenase, free fatty acids (FFA), DPPH radical scavenging activity, tocopherols and tocotrienols. The lowest peroxide values (PVs) were measured in oils of convectional heating (160 oC) and steaming treatments which were performed at temperatures above 100 oC. However, para-anisidine values (pAVs) of samples treated at higher temperatures were considerably greater than those of stabilized at lower temperatures. Oven heating at 160 oC was also one of the most effective treatments on inactivation of lipoxygenase coming after steaming. Steaming also induced a significant reduction in total tocopherols which was directly associated with the greater lost in β-tocopherol content. On the contrary γ- and δ-tocopherols and tocotrienol homologs were abundant with higher amounts in steam applied samples. α-Tocopherol and γ-tocotrienol were the most resistant isomers to stabilization processes. Novelty and scientific contribution. This study shows that the high temperature oven heating method, which is widely used in the industry for thermal stabilization of wheat germ, does not provide an advantage in oxidative stability compared to steaming and microwave applications. Steaming delayed oxidation in germ, while further inhibiting lipoxygenase activity. Moreover, tocotrienols were more conservable. In industrial application, low power in microwave (180 W instead of 360 W), lower temperature in oven heating (90 instead of 160 oC) would be preferable.

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Panait, Diana E., Andreea C. Jufa, Laura Floroian, Alina M. Pascu, Mihaela Badea, Maria Popa, Eugen-Victor Macocian, Gabriela Cioca und Simona Bungau. „Electromagnetic Pollution of the Environment Due Leakage Radiation from Microwave Ovens“. Materiale Plastice 56, Nr. 1 (30.03.2019): 82–86. http://dx.doi.org/10.37358/mp.19.1.5128.

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This study compares the values of the electromagnetic fields generated by three types of microwave ovens with the values available in scientific literature, guides and protocols, considering their impact on human health. Variations in electromagnetic radiation have been determined during and outside the operating time of the microwave ovens at different distances from the oven and in different positions, thereof. The obtained data show higher values of the radiation leakage during operation than those provided by the regulations in force, for all types of studied ovens. The results of the study suggest the need to reduce the time spent near these devices and to optimize the equipment in order to reduce these radiation leakages.

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Ramaswamy, H., und J. Tang. „Microwave and Radio Frequency Heating“. Food Science and Technology International 14, Nr. 5 (Oktober 2008): 423–27. http://dx.doi.org/10.1177/1082013208100534.

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This paper brings to perspective issues related to research initiatives for the application of microwave (MW) and radiofrequency (RF) applications in foods. Both MW (300 MHz and 300 GHz) and RF waves (3 kHz — 300 MHz) are part of the electromagnetic spectrum that result in heating of dielectric materials by induced molecular vibration as a result of dipole rotation or ionic polarization. They have been credited with volumetric heat generation resulting in rapid heating of foodstuffs. Due to their lower frequency levels, RF waves have a larger penetration depth than MW and hence could find better application in larger size foods. Besides the popular domestic use of MW ovens, commercialized applications of MW/RF heating include blanching, tempering, pasteurization, sterilization, drying, rapid extraction, enhanced reaction kinetics, selective heating, disinfestations, etc. This paper reviews the current status and research needs for in-packaged sterilization technologies for commercial applications. Technological challenges include process equipment design, microbial destruction and enzyme inactivation kinetics, temperature and process monitoring, and achieving of temperature uniformity. Other issues also relate to the use of packaging material in in-package sterilization applications, package/container concerns in domestic MW ovens, receptor technology for creating dry-oven conditions, modeling and time-temperature process integrators. There is also the issue of non-thermal and enhanced thermal effects of microwave heating on destruction kinetics.

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Law, Victor J., und Denis P. Dowling. „Converting a Microwave Oven into a Plasma Reactor: A Review“. International Journal of Chemical Engineering 2018 (2018): 1–12. http://dx.doi.org/10.1155/2018/2957194.

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This paper reviews the use of domestic microwave ovens as plasma reactors for applications ranging from surface cleaning to pyrolysis and chemical synthesis. This review traces the developments from initial reports in the 1980s to today’s converted ovens that are used in proof-of-principle manufacture of carbon nanostructures and batch cleaning of ion implant ceramics. Information sources include the US and Korean patent office, peer-reviewed papers, and web references. It is shown that the microwave oven plasma can induce rapid heterogeneous reaction (solid to gas and liquid to gas/solid) plus the much slower plasma-induced solid state reaction (metal oxide to metal nitride). A particular focus of this review is the passive and active nature of wire aerial electrodes, igniters, and thermal/chemical plasma catalyst in the generation of atmospheric plasma. In addition to the development of the microwave oven plasma, a further aspect evaluated is the development of methodologies for calibrating the plasma reactors with respect to microwave leakage, calorimetry, surface temperature, DUV-UV content, and plasma ion densities.

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Qu, Ming Zhe. „Research on the Applications and Measurements of the Microwave Technology“. Applied Mechanics and Materials 556-562 (Mai 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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Cranganu-Cretu, Bogdan, Florea I. Hantila und Teodor Leuca. „Microwave ovens electromagnetic field analysis by means of boundary element method“. Journal of Materials Processing Technology 161, Nr. 1-2 (April 2005): 305–10. http://dx.doi.org/10.1016/j.jmatprotec.2004.07.041.

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Diaz-Ortiz, Angel, Antonio de la Hoz, Jesus Alcazar, Jose Ramon Carrillo, Maria Antonia Herrero, Alberto Fontana und Juan de Mata Munoz. „Reproducibility and Scalability of Solvent-Free Microwave-Assisted Reactions:From Domestic Ovens to Controllable Parallel Applications“. Combinatorial Chemistry & High Throughput Screening 10, Nr. 3 (01.03.2007): 163–69. http://dx.doi.org/10.2174/138620707780126679.

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Bhuvaneswari, Thangavel, Nor Hidayati Abdul Aziz, Jakir Hossen und Chinthakunta Venkataseshaiah. „Field Programmable Gate Array (FPGA) Based Microwave Oven“. Applied Mechanics and Materials 892 (Juni 2019): 120–26. http://dx.doi.org/10.4028/www.scientific.net/amm.892.120.

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In this paper, an FPGA-based microwave oven controller design which can be implemented using Altera DE1 development board is presented. The motivation for this work is to explore FPGA for real time applications. First, a microwave oven controller design architecture that could fit into Altera DE1 board, utilizing on-board peripherals is developed. Then, using the proposed architecture, the design is implemented using Verilog HDL. The microwave oven functionalities are demonstrated using Altera DE1 development board by means of Quartus II 13.0 software. The testbenches are created and waveforms are generated using Modelsim 10.1d software. The simulation results for various cases have been presented and the results confirmed that all the basic functionalities of a practical microwave oven can be realized. The proposed FPGA based controller has a high potential for incorporation in microwave ovens.

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Yoshikawa, Noboru. „Microwave Energy Application for Materials' Processing and Environmental Technology“. Advances in Science and Technology 88 (Oktober 2014): 21–30. http://dx.doi.org/10.4028/www.scientific.net/ast.88.21.

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Microwave heating was discovered more than 60 years ago. And nowadays, it became popular for the use as domestic ovens. Microwave has also been utilized for the industrial processes, such as drying and roasting. On the other hand, there have been many applications of microwave, being investigated for materials' processing and environmental technologies. They are attempted to take advantage of some specific characteristics in microwave heating, which differs from that of the conventional one. Rapid heating, internal heating, selective heating are the features to be taken into consideration. Moreover, so-called "non-thermal effect" is the additional feature in which researchers are particularly interested. In this article, it is intended to describe fundamental aspects in microwave heating and introduce some selected topics of research projects performed in our research group. They include researches on fabrication of some functional materials and on handling industrial wastes etc. In this article, it is also intended to interpret the phenomena observed in these applications from the fundamental view points of electromagnetic wave interaction with materials.

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Brandt, Justin R., und Rosario A. Gerhardt. „Assessment of Homogeneity of Extruded Alumina-SiC Composite Rods Used in Microwave Heating Applications by Impedance Spectroscopy“. MRS Proceedings 1538 (2013): 323–28. http://dx.doi.org/10.1557/opl.2013.657.

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ABSTRACTComposite rods consisting of Alumina (Al2O3) and Silicon Carbide whiskers (SiCw) are used to fabricate microwave cooking racks because they effectively act as a microwave intensification system that allows cooking at much faster rates than conventional microwave ovens. The percolation behavior, electrical conductivity and dielectric properties of these materials have been reported previously. However, it has been observed that the electrical response of the extruded bars is a function of the rod length and that long rods show substantially different behavior than thinner disks cut from them. A percolation model has been proposed that describes the effect of the alignment of the semiconducting SiC whiskers and the quality of the interfaces present in the composite rods: SiC-SiC and SiC-Al2O3-SiC for example. This study was undertaken with the goal of testing out whether the response of the individual sections could be used to generate the response of the full length rods and to assess the importance of the homogeneous distribution of the SiC fillers on the resultant impedance response.

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Gough, C. E., A. Porch, M. J. Lancaster, J. R. Powell, B. Avenhaus, J. J. Wingfield, D. Hung und R. G. Humphreys. „High Tc coplanar resonators for microwave applications and scientific studies“. Physica C: Superconductivity 282-287 (August 1997): 395–98. http://dx.doi.org/10.1016/s0921-4534(97)00284-0.

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Norashiddin, Faris Aiman, Mohamad Anuar Kamaruddin, Muhamad Faizal Pakir Mohamed Latiff und Mohamad Haziq Mohd Hanif. „Sustainable Activated Carbon Production via Microwave for Wastewater Treatment: A Comparative Review“. Borneo Journal of Resource Science and Technology 10, Nr. 1 (01.07.2020): 1–9. http://dx.doi.org/10.33736/bjrst.2030.2020.

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This is an era where the application of adsorption and usage of activated carbons (AC) are considered as mainstream water treatments. The upgrade of these materials may only be through its preparation methods, where most researchers have transitioned from using the conventional furnace methods to using microwave ovens. Derived from various precursors, ACs can be the key in developing numerous environmental applications. This paper reviews the development of production processes of AC from various precursors in the past decades by microwave heating. The importance of the applied methodology and how activating conditions play an influential role, such as carbonisation temperature, activation time, and impregnation ratio are also outlined in this review. From the review of AC production processes, ACs produced from various precursors by chemical method with microwave heating have shown to be the significant factor in developing ACs with relatively higher surface area compared to conventional heating ACs.

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Jain, R. C. „A Survey of Industrial Scientific and Medical Applications of Microwave Energy“. IETE Technical Review 15, Nr. 6 (November 1998): 443–59. http://dx.doi.org/10.1080/02564602.1998.11416778.

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Ulbricht, Gerhard, Mario De Lucia und Eoin Baldwin. „Applications for Microwave Kinetic Induction Detectors in Advanced Instrumentation“. Applied Sciences 11, Nr. 6 (17.03.2021): 2671. http://dx.doi.org/10.3390/app11062671.

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In recent years Microwave Kinetic Inductance Detectors (MKIDs) have emerged as one of the most promising novel low temperature detector technologies. Their unrivaled scalability makes them very attractive for many modern applications and scientific instruments. In this paper we intend to give an overview of how and where MKIDs are currently being used or are suggested to be used in the future. MKID based projects are ongoing or proposed for observational astronomy, particle physics, material science and THz imaging, and the goal of this review is to provide an easily usable and thorough list of possible starting points for more in-depth literature research on the many areas profiting from kinetic inductance detectors.

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Bolomey, J. C. „Recent European developments in active microwave imaging for industrial, scientific, and medical applications“. IEEE Transactions on Microwave Theory and Techniques 37, Nr. 12 (1989): 2109–17. http://dx.doi.org/10.1109/22.44129.

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Jain, R. C., und W. A. G. Voss. „Dielectric Measurement Methods for Industrial Scientific and Medical Applications in Microwave Frequency Range“. IETE Technical Review 11, Nr. 5-6 (September 1994): 297–311. http://dx.doi.org/10.1080/02564602.1994.11437479.

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Giordano, Vincent, Serge Grop, Benoît Dubois, Pierre-Yves Bourgeois, Yann Kersalé, Gregory Haye, Vladimir Dolgovskiy et al. „New-generation of cryogenic sapphire microwave oscillators for space, metrology, and scientific applications“. Review of Scientific Instruments 83, Nr. 8 (August 2012): 085113. http://dx.doi.org/10.1063/1.4747456.

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Bressan, Fernando, Fabrizio Dughiero, Marco Bullo und Paolo Di Barba. „Efficiency optimization of a two-port microwave oven: a robust automated procedure“. COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering 34, Nr. 4 (06.07.2015): 1213–28. http://dx.doi.org/10.1108/compel-05-2014-0109.

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Purpose – In the paper, a single-objective optimization problem characterized by high-frequency field analysis is investigated: the optimal design of a two-port microwave (MW) oven, taking into account the possibility of two independently controlled sources, with the aim of improving the efficiency is considered as the case study. The paper aims to discuss these issues. Design/methodology/approach – A high-frequency field analysis has been coupled to a robust evolutionary-computing algorithm in order to create an appropriate procedure for the optimal design of a MW oven based on a cascade optimization: in the first step the optimized geometry has been identified, while in the second step the optimized electrical supply values have been synthesized. In particular, the direct problem has been faced by means of a 3D-FEM approach in order to obtain realistic results; the inverse problem has been faced by means of a derivative-free robust algorithm based on evolutionary strategy in order to get a fast convergence of the solution. Findings – A new design procedure for high efficiency MW ovens for household application by means of the proposed numerical approach. Practical implications – These results allow industrial designers to improve this kind of devices. Originality/value – The original contribution of the paper is the systematic approach to the optimal design of a MW oven with multiple feeding, based on the link between an algorithm of evolutionary strategy optimization algorithm and a finite-element solver.

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Hewett, D. P., und I. J. Hewitt. „Homogenized boundary conditions and resonance effects in Faraday cages“. Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 472, Nr. 2189 (Mai 2016): 20160062. http://dx.doi.org/10.1098/rspa.2016.0062.

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We present a mathematical study of two-dimensional electrostatic and electromagnetic shielding by a cage of conducting wires (the so-called ‘Faraday cage effect’). Taking the limit as the number of wires in the cage tends to infinity, we use the asymptotic method of multiple scales to derive continuum models for the shielding, involving homogenized boundary conditions on an effective cage boundary. We show how the resulting models depend on key cage parameters such as the size and shape of the wires, and, in the electromagnetic case, on the frequency and polarization of the incident field. In the electromagnetic case, there are resonance effects, whereby at frequencies close to the natural frequencies of the equivalent solid shell, the presence of the cage actually amplifies the incident field, rather than shielding it. By appropriately modifying the continuum model, we calculate the modified resonant frequencies, and their associated peak amplitudes. We discuss applications to radiation containment in microwave ovens and acoustic scattering by perforated shells.

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Savi, Patrizia, Mauro Giorcelli und Simone Quaranta. „Multi-Walled Carbon Nanotubes Composites for Microwave Absorbing Applications“. Applied Sciences 9, Nr. 5 (27.02.2019): 851. http://dx.doi.org/10.3390/app9050851.

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The response of materials to impinging electromagnetic waves is mainly determined by their dielectric (complex permittivity) and magnetic (complex permeability). In particular, radar absorbing materials are characterized by high complex permittivity (and eventually large values of magnetic permeability), Indeed, energy dissipation by dielectric relaxation and carrier conduction are principally responsible for diminishing microwave radiation reflection and transmission in non-magnetic materials. Therefore, the scientific and technological community has been investigating lightweight composites with high dielectric permittivity in order to improve the microwave absorption (i.e., radar cross-section reduction) in structural materials for the aerospace industry. Multiwalled carbon nanotubes films and their composites with different kind of polymeric resins are regarded as promising materials for radar absorbing applications because of their high permittivity. Nanocomposites based on commercial multi-wall carbon nano-tube (MWCNT) fillers dispersed in an epoxy resin matrix were fabricated. The morphology of the filler was analyzed by Field emission scanning electron microscopy (FESEM) and Raman spectroscopy, while the complex permittivity and the radiation reflection coefficient of the composites was measured in the radio frequency range. The reflection coefficient of a single-layer structure backed by a metallic plate was simulated based on the measured permittivity. Simulation achievements were compared to the measured reflection coefficient. Besides, the influence of morphological MWCNT parameters (i.e., aspect ratio and specific surface area) on the reflection coefficient was evaluated. Results verify that relatively low weight percent of MWCNTs are suitable for microwave absorption applications when incorporated into polymer matrixes (i.e., epoxy resin).

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Benyetho, Taoufik, Jamal Zbitou, Larbi El Abdellaoui, Hamid Bennis und Abdelwahed Tribak. „A New Fractal Multiband Antenna for Wireless Power Transmission Applications“. Active and Passive Electronic Components 2018 (2018): 1–10. http://dx.doi.org/10.1155/2018/2084747.

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The Microwave Power Transmission (MPT) is the possibility of feeding a system without contact by using microwave energy. The challenge of such system is to increase the efficiency of transmitted energy from the emitter to the load. This can be achieved by rectifying the microwave energy using a rectenna system composed of an antenna of a significant gain associated with a rectifier with a good input impedance matching. In this paper, a new multiband antenna using the microstrip technology and fractal geometry is developed. The fractal antenna is validated into simulation and measurement in the ISM (industrial, scientific, and medical) band at 2.45 GHz and 5.8 GHz and it presents a wide aperture angle with an acceptable gain for both bands. The final antenna is printed over an FR4 substrate with a dimension of 60 × 30 mm2. These characteristics make the antenna suitable for a multiband rectenna circuit use.

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Zhang, Yong Zhen, Yi Wang, Xue Zhi Zhang und Fei Hou. „Microwave Measuring Instrument Application in the Radar Equipment Maintenance Support“. Applied Mechanics and Materials 687-691 (November 2014): 910–14. http://dx.doi.org/10.4028/www.scientific.net/amm.687-691.910.

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With the development of science and technology ,microwave measuring instrument become more important in the radar equipment maintenance support task.This paper expounds the principles of microwave measuring instrument work and test, describes the application of microwave measuring instrument in the maintenance detection of radar antenna feed system、radar antenna pattern test、power amplifier parameters measurement、the local oscillator test and receiving systems component test. Scientific applications of microwave measuring instrument is the important guarantee to ensure the radar equipment operate effectively.

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Singh, Abhilash, Kumar Gaurav, Ganesh Kumar Meena und Shashi Kumar. „Estimation of Soil Moisture Applying Modified Dubois Model to Sentinel-1; A Regional Study from Central India“. Remote Sensing 12, Nr. 14 (15.07.2020): 2266. http://dx.doi.org/10.3390/rs12142266.

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Surface soil moisture has a wide application in climate change, agronomy, water resources, and in many other domain of science and engineering. Measurement of soil moisture at high spatial and temporal resolution at regional and global scale is needed for the prediction of flood, drought, planning and management of agricultural productivity to ensure food security. Recent advancement in microwave remote sensing, especially after the launch of Sentinel operational satellites has enabled the scientific community to estimate soil moisture at higher spatial and temporal resolution with greater accuracy. This study evaluates the potential of Sentinel-1A satellite images to estimate soil moisture in a semi-arid region. Exactly at the time when satellite passes over the study area, we have collected soil samples at 37 different locations and measured the soil moisture from 5 cm below the ground surface using ML3 theta probe. We processed the soil samples in laboratory to obtain volumetric soil moisture using the oven dry method. We found soil moisture measured from calibrated theta probe and oven dry method are in good agreement with Root Mean Square Error (RMSE) 0.025 m 3 /m 3 and coefficient of determination (R 2 ) 0.85. We then processed Sentinel-1A images and applied modified Dubois model to calculate relative permittivity of the soil from the backscatter values ( σ ∘ ). The volumetric soil moisture at each pixel is then calculated by applying the universal Topp’s model. Finally, we masked the pixels whose Normalised Difference Vegetation Index (NDVI) value is greater than 0.4 to generate soil moisture map as per the Dubois NDVI criterion. Our modelled soil moisture accord with the measured values with RMSE = 0.035 and R 2 = 0.75. We found a small bias in the modelled soil moisture ( 0.02 m 3 / m 3 ). However, this has reduced significantly ( 0.001 m 3 / m 3 ) after applying a bias correction based on Cumulative Distribution Function (CDF) matching. Our approach provides a first-order estimate of soil moisture from Sentinel-1A images in sparsely vegetated agricultural land.

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Chwala, Christian, Felix Keis und Harald Kunstmann. „Real-time data acquisition of commercial microwave link networks for hydrometeorological applications“. Atmospheric Measurement Techniques 9, Nr. 3 (09.03.2016): 991–99. http://dx.doi.org/10.5194/amt-9-991-2016.

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Abstract. The usage of data from commercial microwave link (CML) networks for scientific purposes is becoming increasingly popular, in particular for rain rate estimation. However, data acquisition and availability is still a crucial problem and limits research possibilities. To overcome this issue, we have developed an open-source data acquisition system based on the Simple Network Management Protocol (SNMP). It is able to record transmitted and received signal levels of a large number of CMLs simultaneously with a temporal resolution of up to 1 s. We operate this system at Ericsson Germany, acquiring data from 450 CMLs with minutely real-time transfer to our database. Our data acquisition system is not limited to a particular CML hardware model or manufacturer, though. We demonstrate this by running the same system for CMLs of a different manufacturer, operated by an alpine ski resort in Germany. There, the data acquisition is running simultaneously for four CMLs with a temporal resolution of 1 s. We present an overview of our system, describe the details of the necessary SNMP requests and show results from its operational application.

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Chwala, C., F. Keis und H. Kunstmann. „Real time data acquisition of commercial microwave link networks for hydrometeorological applications“. Atmospheric Measurement Techniques Discussions 8, Nr. 11 (23.11.2015): 12243–62. http://dx.doi.org/10.5194/amtd-8-12243-2015.

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Abstract. The usage of data from commercial microwave link (CML) networks for scientific purposes is becoming increasingly popular, in particular for rain rate estimation. However, data acquisition and availability is still a crucial problem and limits research possibilities. To overcome this issue, we have developed an open source data acquisition system based on the Simple Network Management Protocol (SNMP). It is able to record transmitted- and received signal levels of a large number of CMLs simultaneously with a temporal resolution of up to one second. We operate this system at Ericsson Germany, acquiring data from 450 CMLs with minutely real time transfer to our data base. Our data acquisition system is not limited to a particular CML hardware model or manufacturer, though. We demonstrate this by running the same system for CMLs of a different manufacturer, operated by an alpine skiing resort in Germany. There, the data acquisition is running simultaneously for four CMLs with a temporal resolution of one second. We present an overview of our system, describe the details of the necessary SNMP requests and show results from its operational application.

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Wagner, Wolfgang, Günter Blöschl, Paolo Pampaloni, Jean-Christophe Calvet, Bizzarro Bizzarri, Jean-Pierre Wigneron und Yann Kerr. „Operational readiness of microwave remote sensing of soil moisture for hydrologic applications“. Hydrology Research 38, Nr. 1 (01.02.2007): 1–20. http://dx.doi.org/10.2166/nh.2007.029.

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Microwave remote sensing of soil moisture has been an active area of research since the 1970s but has yet found little use in operational applications. Given recent advances in retrieval algorithms and the approval of a dedicated soil moisture satellite, it is time to re-assess the potential of various satellite systems to provide soil moisture information for hydrologic applications in an operational fashion. This paper reviews recent progress made with retrieving surface soil moisture from three types of microwave sensors – radiometers, Synthetic Aperture Radars (SARs), and scatterometers. The discussion focuses on the operational readiness of the different techniques, considering requirements that are typical for hydrological applications. It is concluded that operational coarse-resolution (25–50 km) soil moisture products can be expected within the next few years from radiometer and scatterometer systems, while scientific and technological breakthroughs are still needed for operational soil moisture retrieval at finer scales (<1 km) from SAR. Also, further research on data assimilation methods is needed to make best use of the coarse-resolution surface soil moisture data provided by radiometer and scatterometer systems in a hydrologic context and to fully assess the value of these data for hydrological predictions.

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Mgbemena, Chinedum Ogonna, Danning Li, Meng-Fang Lin, Paul Daniel Liddel, Kali Babu Katnam, Vijay Kumar Thakur und Hamed Yazdani Nezhad. „Accelerated microwave curing of fibre-reinforced thermoset polymer composites for structural applications: A review of scientific challenges“. Composites Part A: Applied Science and Manufacturing 115 (Dezember 2018): 88–103. http://dx.doi.org/10.1016/j.compositesa.2018.09.012.

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Ahmed, Kawan F., und Rawaz H. Abdullah. „Design and Simulation of Microstrip Patch Antenna for Wireless Applications“. Kurdistan Journal of Applied Research 2, Nr. 3 (27.08.2017): 365–68. http://dx.doi.org/10.24017/science.2017.3.27.

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In this paper two rectangular microstrip patch antennas are designed to operate in and bands, using Computer Simulation Technology (CST) Microwave Studio. The designed antenna can be used for industrial, scientific and medical (ISM) band applications. The RO4350B hydrocarbon ceramic laminates from ROGRES corporation substrate is chosen in the design of the dielectric substrate of the antennas. The designed antenna has low profile, low cost, easy fabrication and good isolation. The parameters such as return loss, voltage standing wave ratio (VSWR), antenna gain, radiation pattern has been simulated and analyzed.

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Lu, Wei-Bing, Hui Chen und Zhen-Guo Liu. „A review of microwave devices based on CVD-grown graphene with experimental demonstration“. EPJ Applied Metamaterials 6 (2019): 8. http://dx.doi.org/10.1051/epjam/2019001.

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As a two-dimension planar material with zero-gap structure, graphene has a lot of outstanding properties in microwave frequency band, and the chemical vapor deposition (CVD) method can produce the large-scale graphene sheets with high quality for applications. Thus, the study about the microwave devices based on CVD-grown graphene has been aroused wide interests in the past few years. In this paper, mainly concentrating on the research by Chinese scientific groups, we review the development of microwave devices based on the CVD-grown graphene which are all validated by experiments, including attenuators, absorbers, antennas, electromagnetic interference (EMI) shielding and beam reconfiguration.

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Garmire, Elsa. „Stimulated Brillouin Review: Invented 50 Years Ago and Applied Today“. International Journal of Optics 2018 (02.12.2018): 1–17. http://dx.doi.org/10.1155/2018/2459501.

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Stimulated Brillouin scattering (SBS) is embedded today in a variety of optical systems, such as advanced high-power lasers, sensors, microwave signal processors, scientific instrumentation, and optomechanical systems. Reduction in SBS power requirements involves use of optical fibers, integrated optics, micro-optic devices, and now nano-optics, often in high Q cavities. It has taken fifty years from its earliest invention by conceptual discovery until today for SBS to become a practical and useful technology in a variety of applications. Some of these applications are explained and it is shown how they are tied to particular attributes of SBS: phase conjugation, frequency shifts, low noise, narrow linewidth, frequency combs, optical and microwave signal processing, etc.

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Cadeddu, M. P., J. C. Liljegren und D. D. Turner. „The Atmospheric radiation measurement (ARM) program network of microwave radiometers: instrumentation, data, and retrievals“. Atmospheric Measurement Techniques 6, Nr. 9 (12.09.2013): 2359–72. http://dx.doi.org/10.5194/amt-6-2359-2013.

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Abstract. The Climate Research Facility of the US Department of Energy's Atmospheric Radiation Measurement (ARM) Program operates a network of ground-based microwave radiometers. Data and retrievals from these instruments have been available to the scientific community for almost 20 yr. In the past five years the network has expanded to include a total of 22 microwave radiometers deployed in various locations around the world. The new instruments cover a frequency range between 22 and 197 GHz and are consistently and automatically calibrated. The latest addition to the network is a new generation of three-channel radiometers, currently in the early stage of deployment at all ARM sites. The network has been specifically designed to achieve increased accuracy in the retrieval of precipitable water vapor (PWV) and cloud liquid water path (LWP) with the long-term goal of providing the scientific community with reliable, calibrated radiometric data and retrievals of important geophysical quantities with well-characterized uncertainties. The radiometers provide high-quality, continuous datasets that can be utilized in a wealth of applications and scientific studies. This paper presents an overview of the microwave instrumentation, calibration procedures, data, and retrievals that are available for download from the ARM data archive.

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Cadeddu, M. P., J. C. Liljegren und D. D. Turner. „The Atmospheric Radiation Measurement (ARM) program network of microwave radiometers: instrumentation, data, and retrievals“. Atmospheric Measurement Techniques Discussions 6, Nr. 2 (15.04.2013): 3723–63. http://dx.doi.org/10.5194/amtd-6-3723-2013.

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Abstract. The Climate Research Facility of the US Department of Energy's Atmospheric Radiation Measurement (ARM) Program operates a network of ground-based microwave radiometers. Data and retrievals from these instruments have been available to the scientific community for almost 20 yr. In the past five years the network has been expanded to include a total of 22 microwave radiometers deployed in various locations around the world. The new instruments cover a frequency range between 22 and 197 GHz and are consistently and automatically calibrated. The latest addition to the network is a new generation of three-channel radiometers currently in the early stage of deployment at all ARM sites. The network has been specifically designed to achieve increased accuracy in the retrieval of precipitable water vapor (PWV) and cloud liquid water path (LWP) with the long-term goal of providing the scientific community with reliable, calibrated radiometric data and retrievals of important geophysical quantities with well-characterized uncertainties. The radiometers provide high-quality, continuous datasets that can be utilized in a wealth of applications and scientific studies. This paper presents an overview of the microwave instrumentation, calibration procedures, data, and retrievals that are available for download from the ARM data archive.

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Jákói, Zoltán, Balázs Lemmer, Cecilia Hodúr und Sándor Beszédes. „Microwave and Ultrasound Based Methods in Sludge Treatment: A Review“. Applied Sciences 11, Nr. 15 (30.07.2021): 7067. http://dx.doi.org/10.3390/app11157067.

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The amount of waste activated sludge (WAS) is increasing annually, and since it presents potential environmental and health-related risks, an appropriate treatment and stabilization process is needed. It has been shown in numerous studies in the past few decades that amongst the advanced treatment methods of sludge, microwave and ultrasound-based processes offer promising and effective alternatives. The main advantage of these physical methods is that they are energy-efficient, easy to implement and can be combined with other types of treatment procedures without major difficulties. In this review article we would like to present the recent scientific results of the microwave, ultrasound and combined (microwave-alkaline, microwave-H2O2, ultrasound-alkaline and ultrasound-H2O2) treatment of wastewater sludge, in terms of different process-efficiency indicators. Although the obtained results somewhat vary between the different scientific papers, it can be undoubtedly stated that both MW and US—either individually or in combination with chemical treatments—can enhance several aspects of sludge processing, like increasing the SCOD/TCOD rate, disintegration degree (DD), or the anaerobic digestibility (AD), but the extent of these increments clearly depends on the treatment conditions or parameters.

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Palma, Vincenzo, Daniela Barba, Marta Cortese, Marco Martino, Simona Renda und Eugenio Meloni. „Microwaves and Heterogeneous Catalysis: A Review on Selected Catalytic Processes“. Catalysts 10, Nr. 2 (18.02.2020): 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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Ding, Longting, Xuancang Wang, Wengang Zhang, Shuai Wang, Jing Zhao und Yongquan Li. „Microwave Deicing Efficiency: Study on the Difference between Microwave Frequencies and Road Structure Materials“. Applied Sciences 8, Nr. 12 (23.11.2018): 2360. http://dx.doi.org/10.3390/app8122360.

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A method of deicing using microwave heating is proposed to make scientific and economical road deicing in a cold area, and to make up for deficiencies in the existing methods for melting snow and ice. This paper proposes to define microwave deicing efficiency as the heating rate of a concrete surface when heated to 0 °C (the efficiency of deicing is equal to the difference divided by heating time, which is between 0 °C and the initial temperature at the junction of ice and concrete). Based on the mechanism of microwave heating and deicing, a method combining the finite element simulation model with indoor experiments was proposed to study the deicing efficiency of microwaves, and the effects of different microwave frequencies and different road structure materials on microwave deicing efficiency were analyzed. The results show that the microwave frequency and road structure materials have a great influence on microwave deicing. For asphalt concrete, the ice melting efficiency of 5.8 GHz is 4.31 times that of 2.45 GHz, but the heating depth is less than that of 2.45 GHz. At 2.45 GHz, the melting efficiency of cement concrete is 3.89 times that of asphalt concrete. At 5.8 GHz, the melting efficiency of cement concrete is 5.23 times that of asphalt concrete. Through the consistency of the simulation and experimental results, the validity of the simulation model based on the finite element theory is verified. The results provide theoretical guidance and a practical basis for future applications of microwave deicing.

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Al-Obaidi, Mohammed K., Ezri Mohd, Noorsaliza Abdullah, Samsul Haimi Dahlan und Jawad Ali. „Design and implementation of microstrip rotman lens for ISM band applications“. Bulletin of Electrical Engineering and Informatics 8, Nr. 1 (01.03.2019): 90–98. http://dx.doi.org/10.11591/eei.v8i1.1392.

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This work presents the design and implementation of Rotman lens as a beam steering device for Industrial, Scientific, and Medical (ISM) applications. 2.45 GHz is considered as a center frequency design with (2-6) GHz frequency bandwidth. The beam steering is examined to cover ±21o scan angle with maximum main lobe magnitude 10.1 dBi, rectangular patch antennas are used as radiation elements to beam the output far field. The work is extended to compare between the tapered line which is used for matching between 50-Ω ports and lens cavity. CST microwave simulation studio results show that the rectangular taper line can yield 2 dB return loss less than linear taper line with a little bit shifting in responses for same input and load impedance.

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Rossignol, Jerome, und Alain Thionnet. „Damage in Composite Material: A Microwave Detection“. Key Engineering Materials 605 (April 2014): 303–5. http://dx.doi.org/10.4028/www.scientific.net/kem.605.303.

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In the field of the transport, the increase of the security rule recommends to a periodic control of the structure to detect damage due to mechanical loadings. Now, current materials, used in the case of transport applications, are the composite materials. The methods, to control these materials or composite structures, need to be low cost, non-destructive, in-situ and swiftness as far as possible. The scientific literature reports many methods to control the damage in composite materials and structures. However the above requirements and the adaptation to composite materials reduce the number of methods that can be used. Currently, the adapted methods are based on infrared thermography, acoustical emission, EMIR (ElectroMagnetic InfraRed) or microwave imagery. We present an innovative non-destructive method of detecting damages in composite materials. The method is based on the observation and analysis of the modification in dielectric material resulting from damage. The originality of this method is that the diagnostic is obtained by using a microstrip resonator at microwave frequencies. The feasibility of the method is demonstrated by the detection of a fibre break into an unidirectional composite submitted to a flexural loading. The fibre break is the damage to detect. The perspective of this work is to develop a quantification and a localization of damages.

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Kaur, Jaswinder, Rajesh Khanna und Machavaram Kartikeyan. „Novel dual-band multistrip monopole antenna with defected ground structure for WLAN/IMT/BLUETOOTH/WIMAX applications“. International Journal of Microwave and Wireless Technologies 6, Nr. 1 (25.09.2013): 93–100. http://dx.doi.org/10.1017/s1759078713000858.

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In the present work, a novel multistrip monopole antenna fed by a cross-shaped stripline comprising one vertical and two horizontal strips has been proposed for wireless local area network (WLAN)/Industrial, Scientific, and Medical band (ISM)/International Mobile Telecommunication (IMT)/BLUETOOTH/Worldwide Interoperability for Microwave Access (WiMAX) applications. The designed antenna has a small overall size of 20 × 30 mm2. The goal of this paper is to use defected ground structure (DGS) in the proposed antenna design to achieve dual-band operation with appreciable impedance bandwidth at the two operating modes satisfying several communication standards simultaneously. The antenna was simulated using Computer Simulation Technology Microwave Studio (CST MWS) V9 based on the finite integration technique (FIT) with perfect boundary approximation. Finally, the proposed antenna was fabricated and some performance parameters were measured to validate against simulation results. The design procedure, parametric analysis, simulation results along with measurements for this multistrip monopole antenna using DGS operating simultaneously at WLAN (2.4/5.8 GHz), IMT (2.35 GHz), BLUETOOTH (2.45 GHz), and WiMAX (5.5 GHz) are presented.

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Rachakh, Amine, Larbi El Abdellaoui, Jamal Zbitou, Ahmed Errkik, Abdelali Tajmouati und Mohamed Latrach. „A Novel Configuration of A Microstrip Power Amplifier based on GaAs-FET for ISM Applications“. International Journal of Electrical and Computer Engineering (IJECE) 8, Nr. 5 (01.10.2018): 3882. http://dx.doi.org/10.11591/ijece.v8i5.pp3882-3889.

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Power Amplifiers (PA) are very indispensable components in the design of numerous types of communication transmitters employed in microwave technology. The methodology is exemplified through the design of a 2.45GHz microwave power Amplifier (PA) for the industrial, scientific and medical (ISM) applications using microstrip technology. The main design target is to get a maximum power gain while simultaneously achieving a maximum output power through presenting the optimum impedance which is characteristically carried out per adding a matching circuit between the source and the input of the power amplifier and between the load and the output of the power amplifier. A "T" matching technique is used at the input and the output sides of transistor for assure in band desired that this circuit without reflections and to obtain a maximum power gain. The proposed power amplifier for microwave ISM applications is designed, simulated and optimized by employing Advanced Design System (ADS) software by Agilent. The PA shows good performances in terms of return loss, output power, power gain and stability; the circuit has an input return loss of -38dB and an output return loss of -33.5dB. The 1-dB compression point is 8.69dBm and power gain of the PA is 19.4dBm. The Rollet's Stability measure B1 and the stability factor K of the amplifier is greater than 0 and 1 respectively, which shows that the circuit is unconditionally stable. The total chip size of the PA is 73.5× 36 mm2.

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Pohlmann, Jan-Dag, Marko Freese, Stefan Reiser und Reinhold Hanel. „Evaluation of lethal and nonlethal assessment methods of muscle fat content in European eel (Anguilla anguilla)“. Canadian Journal of Fisheries and Aquatic Sciences 76, Nr. 4 (April 2019): 569–75. http://dx.doi.org/10.1139/cjfas-2018-0032.

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Individual fat reserves are considered a key factor for the reproductive fitness of the endangered European eel (Anguilla anguilla). In contrast with most established standards, microwave measurements enable the determination of fat contents without sacrificing individual fish, offering a broad range of ecological applications. To test the reliability of nonlethal assessment methods of the muscle fat content in eels, the performance of microwave measurements was compared with the prevailing standard of measuring fat in a distinct subsample of muscle tissue by solvent extraction. Results indicate that either method is prone to error due to physiological and morphological changes during the sexual maturation of eels. Since microwave measurements were systematically affected by life stage and body length, it was possible to calibrate the method accordingly, putting it at least on par with the prevailing standard and further facilitating its use for scientific purposes.

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Juan, Carlos G., Benjamin Potelon, Cédric Quendo und Enrique Bronchalo. „Microwave Planar Resonant Solutions for Glucose Concentration Sensing: A Systematic Review“. Applied Sciences 11, Nr. 15 (29.07.2021): 7018. http://dx.doi.org/10.3390/app11157018.

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The measurement of glucose concentration finds interesting potential applications in both industry and biomedical contexts. Among the proposed solutions, the use of microwave planar resonant sensors has led to remarkable scientific activity during the last years. These sensors rely on the changes in the dielectric properties of the medium due to variations in the glucose concentration. These devices show electrical responses dependent on the surrounding dielectric properties, and therefore the changes in their response can be related to variations in the glucose content. This work shows an up-to-date review of this sensing approach after more than one decade of research and development. The attempts involved are sorted by the sensing parameter, and the computation of a common relative sensitivity to glucose is proposed as general comparison tool. The manuscript also discusses the key points of each sensor category and the possible future lines and challenges of the sensing approach.

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Ayari, Mohamed, Yamen El Touati und Saleh Altowaijri. „Method of Moments versus Advanced Transverse Wave Approach for EM Validation of Complex Microwave and RF Applications“. Journal of Electromagnetic Engineering and Science 20, Nr. 1 (31.01.2020): 31–38. http://dx.doi.org/10.26866/jees.2020.20.1.31.

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The art of benchmarking study has improved at an astonishing rate the scientific research in all areas but mainly in microwave engineering domain, and in particular, the field of microwave (MW) and radiofrequency (RF) integrated circuit design. Moreover, the fast simulation of complex MF/RF structures is considered a big challenge for the simulators, mainly in light of the continuous information and communication technology (ICT) development. In this context, the present paper sets out to present two important numerical electromagnetic (EM) methods, the method of moments (MOM) and our advanced transverse wave approach (A-TWA) for full-wave analysis of RF/MW structures. The computational complexity of these methods is evaluated. Two complex printed antennas working in the RF/MW range are selected and investigated. The EM problems that can be found in these circuits and that could not be solved analytically or by other numerical methods are discussed. The EM-validation of the studied structures using A-TWA and MOM is demonstrated and compared in the context of RF/MW applications. The obtained simulation results prove the efficiency and rapidity of our approach in comparison with the literature.

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Bhagat, Vijay. „Space borne Active Microwave Remote Sensing of Soil Moisture: A Review“. Remote Sensing of Land 1, Nr. 1 (03.11.2017): 53–86. http://dx.doi.org/10.21523/gcj1.17010104.

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Space-borne active microwave remote sensing is an efficient technique to acquire knowledge of land surface soil moisture (SM). Several studies have reported comparable results of surface SM using space-borne scatterometer responses to backscattering from soil layer. However, detection and measuring of SM using these techniques require an appropriate filtering of data, site-specific calibration of surface roughness parameters, prior knowledge of the study area, specific research purpose, careful selection of model, different suitable datasets with appropriate time series, etc. Reported success studies are very site-, data- and situation-specific and show uncertainty in SM estimations therefore, insufficient to reach global conclusions and applications. Scientific challenge before the community is to develop or modify models and appropriate datasets for SM estimations with simplification and high precision with global applicability for complex bio-physical units. The field is new, active, attractive, challenging and interesting area of research for sustainable land and climate change management.

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Santiago, I., und M. D. Calzada. „Population Measurement of the 3p54s Configuration Levels in an Argon Microwave Plasma at Atmospheric Pressure“. Applied Spectroscopy 61, Nr. 7 (Juli 2007): 725–33. http://dx.doi.org/10.1366/000370207781393343.

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Metastable atoms, due to their intrinsic properties, are very useful to characterize plasma and to control the scientific and technological applications carried out with it. This paper describes the implementation of a method to determine the densities of the argon 3p54s metastable and resonant levels in a microwave plasma at atmospheric pressure. Because the method is based on the self-absorption of the radiation emitted by the plasma, no external radiation source is needed. Using this method, the populations of the four levels of the 3p54s argon configuration were found to be in the range 1010–1012 cm−3, in agreement with the values found in the literature.

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Pelicano, Ana Catarina, und Raquel C. Conceição. „Development of a 3D Anthropomorphic Phantom Generator for Microwave Imaging Applications of the Head and Neck Region“. Sensors 20, Nr. 7 (04.04.2020): 2029. http://dx.doi.org/10.3390/s20072029.

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The development of 3D anthropomorphic head and neck phantoms is of crucial and timely importance to explore novel imaging techniques, such as radar-based MicroWave Imaging (MWI), which have the potential to accurately diagnose Cervical Lymph Nodes (CLNs) in a neoadjuvant and non-invasive manner. We are motivated by a significant diagnostic blind-spot regarding mass screening of LNs in the case of head and neck cancer. The timely detection and selective removal of metastatic CLNs will prevent tumor cells from entering the lymphatic and blood systems and metastasizing to other body regions. The present paper describes the developed phantom generator which allows the anthropomorphic modelling of the main biological tissues of the cervical region, including CLNs, as well as their dielectric properties, for a frequency range from 1 to 10 GHz, based on Magnetic Resonance images. The resulting phantoms of varying complexity are well-suited to contribute to all stages of the development of a radar-based MWI device capable of detecting CLNs. Simpler models are essential since complexity could hinder the initial development stages of MWI devices. Besides, the diversity of anthropomorphic phantoms resulting from the developed phantom generator can be explored in other scientific contexts and may be useful to other medical imaging modalities.

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Vakhin, Alexey V., Mohammed Amine Khelkhal, Arash Tajik, Marat R. Gafurov, Oleg G. Morozov, Aydar R. Nasybullin, Sergey A. Karandashov et al. „The Role of Nanodispersed Catalysts in Microwave Application during the Development of Unconventional Hydrocarbon Reserves: A Review of Potential Applications“. Processes 9, Nr. 3 (26.02.2021): 420. http://dx.doi.org/10.3390/pr9030420.

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Electromagnetic impact on oil reservoir manifests itself in various physical and chemical phenomena and attracts a significant scientific and technological interest. Microwave (MW) radiation heating can be more efficient for the oil recovery than heat transfer by convection or by thermal conduction. MW influence can also lead to significant changes in the physicochemical and rheological properties of oil caused by chemical processes of transformation of the oil high-molecular components such as resins and asphaltenes. The efficiency of transition-metal catalysts applied for the in-situ conversion of hydrocarbons directly in the reservoir might be significantly increased by exposing the oil formation to MW radiation. Actually, transition metals nanoparticles and their oxides are considered as active absorbers of MW radiation and; therefore, they can be used to intensify MW impact on the reservoir. Catalyst particles dispersed in the formation provide enhanced MW sweep. Taken together, the functioning of the catalysts and the effect of microwave radiation provide deep conversion of resins and asphaltenes, a decrease in the viscosity of the produced oil and an increase in oil recovery factor, along with a decrease in water cut of the well production. The present review analyzes the latest works on the combined application of microwave exposure and dispersed catalysts. In addition, this review discusses the prospects and perspectives of practical application of electromagnetic heating to enhance heavy oil recovery in the presence of nanoparticles.

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González-Penella, Vicente J., Francisco Beltrán Berenguer, Jaime Martínez Verdú, Celia Guillem López, Ángel M. López-Buendía und Javier Martínez-Mingote Navarro. „Energy Analysis in the Natural Stone Manufacturing Process“. Key Engineering Materials 548 (April 2013): 57–64. http://dx.doi.org/10.4028/www.scientific.net/kem.548.57.

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The current socio-economic situation, characterized by energy problems and environmental concerns, urgently requires an innovative intervention. Such action should be carried out in order to improve competitiveness and the strength of companies in general, and those belonging to the natural stone sector in particular. Production processes provide the largest source of data within a factory and it is therefore necessary to carry out an energy analysis, as it is a prerequisite for informed decision-making. This energy analysis would identify those areas where most energy is consumed. Consequently, an energy analysis was conducted on two of the most representative production processes (slab and tile production). First of all, researchers analysed each stage of the production process using IDEF0 standard notation. Previously, the power consumption was monitored from both electrical and thermal perspective and, using several energy indicators, an energy balance had been carried out. As a result of this analysis, the significance of electricity compared to gas was clearly identified; the analysis also showed that cutting and abrasive processes were more critical from an electrical point of view (in that order). Another important finding was that related to thermal energy: reinforcement processes were those with the greatest significance (and in particular those performed in ovens). Based on the conclusions of the energy analysis, it was possible to establish new research lines: design of cutting disc and multiblade framesaws, microwave curing technology applications, etc. Those research lines would therefore provide the most significant beneficial effects on the environment and energy saving and, hence, companies can overcome the current economic situation.

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Rahayu, Endah Fitriani, Bunnari Bunnari und Andri Hardyansyah. „Reduction of Graphene Oxide: Controlled Synthesis by Microwave Irradiation“. Molekul 15, Nr. 1 (23.03.2020): 56. http://dx.doi.org/10.20884/1.jm.2020.15.1.564.

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Graphene has been attracting enormous attention in the scientific community because of its unique properties and use for various applications. Graphene has been synthesized in various ways, one of which is the graphite oxidation method to form graphene oxide (GO). Reduction of GO to reduced graphene oxide (RGO) is necessary to recover the conjugated network and electrical conductivity, and for this research, this was achieved using microwave irradiation. Microwave synthesis provides an alternative method, saving more time in the reaction process. In this research, graphene was synthesized from graphite by the modified Hummers method and microwave irradiation. This research proves that graphene can be synthesized with a high-quality structure and in a shorter amount of time using microwave irradiation to reduce GO. With longer microwave exposure, less GO is present in the sample, as indicated by the absence of an n–π* electronic transition in the absorbance graph and the absence of oxide groups in the Fourier-Transform Infra-Red spectrum. With increasing microwave power, the reduction process is short-lived, and better quality RGO is produced. This study shows that the new reduction process occurs within 20 minutes with a power of 450 and 630 watts, but at 900 watts, the reduction of GO occurs within 10 minutes, as shown by UV-Vis and FTIR spectra.

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Kulandhaisamy, Indhumathi, Dinesh Babu Rajendran, Malathi Kanagasabai, Balaji Moorthy, Jithila V. George und Livya Lawrance. „Dual-frequency phase shifter deploying complementary split-ring resonator“. International Journal of Microwave and Wireless Technologies 8, Nr. 7 (26.06.2015): 1045–50. http://dx.doi.org/10.1017/s1759078715001051.

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Phase shifters are indispensable microwave components. In this paper, a dual-frequency, passive, analog, and reciprocal phase shifter is proposed, deploying the phase-delay characteristics of complementary split-ring resonator (CSRR). A transmission line is loaded with a pair of CSRR in the ground plane and the phase variations are compared with an ideal transmission line. The proposed phase shifter operates in the industrial, scientific and medical (ISM) and wireless local area network (WLAN) bands, providing a phase of 180° at 2.4 GHz and 90° at 5.4 GHz for beam steering applications.

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Sajjadi, Baharak, Wei-Yin Chen und Nosa O. Egiebor. „A comprehensive review on physical activation of biochar for energy and environmental applications“. Reviews in Chemical Engineering 35, Nr. 6 (26.07.2019): 735–76. http://dx.doi.org/10.1515/revce-2017-0113.

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Abstract Biochar is a solid by-product of thermochemical conversion of biomass to bio-oil and syngas. It has a carbonaceous skeleton, a small amount of heteroatom functional groups, mineral matter, and water. Biochar’s unique physicochemical structures lead to many valuable properties of important technological applications, including its sorption capacity. Indeed, biochar’s wide range of applications include carbon sequestration, reduction in greenhouse gas emissions, waste management, renewable energy generation, soil amendment, and environmental remediation. Aside from these applications, new scientific insights and technological concepts have continued to emerge in the last decade. Consequently, a systematic update of current knowledge regarding the complex nature of biochar, the scientific and technological impacts, and operational costs of different activation strategies are highly desirable for transforming biochar applications into industrial scales. This communication presents a comprehensive review of physical activation/modification strategies and their effects on the physicochemical properties of biochar and its applications in environment-related fields. Physical activation applied to the activation of biochar is discussed under three different categories: I) gaseous modification by steam, carbon dioxide, air, or ozone; II) thermal modification by conventional heating and microwave irradiation; and III) recently developed modification methods using ultrasound waves, plasma, and electrochemical methods. The activation results are discussed in terms of different physicochemical properties of biochar, such as surface area; micropore, mesopore, and total pore volume; surface functionality; burn-off; ash content; organic compound content; polarity; and aromaticity index. Due to the rapid increase in the application of biochar as adsorbents, the synergistic and antagonistic effects of activation processes on the desired application are also covered.

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