Pub Date : 2020-07-21DOI: 10.1080/08327823.2020.1794724
Habib Dogan, I. Basyigit, A. Genç
Abstract In order to exploit the use of remote sensing, microwave heating/drying and water stress in the agricultural sector, it is necessary to determine the dielectric properties of plant materials (branches, leaves, roots, fruits). In this way, the yield and quality of agricultural products can be increased. In this study, dielectric parameters of the sweet cherry and sour cherry leaves are measured by waveguide transmission line Method. The dielectric properties of the leaves (varying moisture content) are measured over a frequency ranging from (3.30–7.05 GHz) using WR229 (3.30–4.90 GHz) and WR159 (4.90–7.05 GHz) waveguide structures. A novel curve fitting technique is used to characterize dielectric properties of sweet cherry leaves. In order to verify the accuracy of the model the data obtained using this methodology is compared with measurement data of sour cherry leaves belonging to the same family. The determination coefficient R2 of the model for WR229 and WR159 are 0.996 and 0.998, respectively. Similarly, the Root Mean Square Error (RMSE) values of the model for WR229 and WR159 are 0.852 and 0.236, respectively.
{"title":"Determination and modelling of dielectric properties of the cherry leaves of varying moisture content over 3.30–7.05 GHz frequency range","authors":"Habib Dogan, I. Basyigit, A. Genç","doi":"10.1080/08327823.2020.1794724","DOIUrl":"https://doi.org/10.1080/08327823.2020.1794724","url":null,"abstract":"Abstract In order to exploit the use of remote sensing, microwave heating/drying and water stress in the agricultural sector, it is necessary to determine the dielectric properties of plant materials (branches, leaves, roots, fruits). In this way, the yield and quality of agricultural products can be increased. In this study, dielectric parameters of the sweet cherry and sour cherry leaves are measured by waveguide transmission line Method. The dielectric properties of the leaves (varying moisture content) are measured over a frequency ranging from (3.30–7.05 GHz) using WR229 (3.30–4.90 GHz) and WR159 (4.90–7.05 GHz) waveguide structures. A novel curve fitting technique is used to characterize dielectric properties of sweet cherry leaves. In order to verify the accuracy of the model the data obtained using this methodology is compared with measurement data of sour cherry leaves belonging to the same family. The determination coefficient R2 of the model for WR229 and WR159 are 0.996 and 0.998, respectively. Similarly, the Root Mean Square Error (RMSE) values of the model for WR229 and WR159 are 0.852 and 0.236, respectively.","PeriodicalId":16556,"journal":{"name":"Journal of Microwave Power and Electromagnetic Energy","volume":"54 1","pages":"254 - 270"},"PeriodicalIF":1.5,"publicationDate":"2020-07-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87377942","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-07-02DOI: 10.1080/08327823.2020.1794722
A. O. Kizilçay, Y. Akinay
Abstract In this paper, the electromagnetic shielding effectiveness results of the plain weave composite fabric and the analytical solution of metal mesh were investigated. The composite fabric made of cotton yarns twisted with 50 µm copper filaments was used in the experiment. As the fabric was weaved and stretched, it had square shaped apertures which had length of 1.2 mm. The electromagnetic shielding effectiveness of these fabrics was measured in the frequency range of 1.7–2.6 GHz via WR430 waveguide system. In order to model the shielding results of the aforementioned fabric, an analytical solution which facilitates to calculate shielding effectiveness of metal mesh, was taken into consideration. Due to the physical similarity between the fabric geometry and metal mesh structure, the values of fabric characteristics were substituted in analytical solution. A statistical approach showed that the measured SE results of plain weave composite fabric fitted in the analytical solution for metal mesh in 1.82–2.6 GHz frequency range with strength of 30–36 dB. Thus, depending on desired shielding efficiency the physical texture of shielding fabric can be determined analytically.
{"title":"Equivalent analytical model of plain weave composite fabric for electromagnetic shielding applications","authors":"A. O. Kizilçay, Y. Akinay","doi":"10.1080/08327823.2020.1794722","DOIUrl":"https://doi.org/10.1080/08327823.2020.1794722","url":null,"abstract":"Abstract In this paper, the electromagnetic shielding effectiveness results of the plain weave composite fabric and the analytical solution of metal mesh were investigated. The composite fabric made of cotton yarns twisted with 50 µm copper filaments was used in the experiment. As the fabric was weaved and stretched, it had square shaped apertures which had length of 1.2 mm. The electromagnetic shielding effectiveness of these fabrics was measured in the frequency range of 1.7–2.6 GHz via WR430 waveguide system. In order to model the shielding results of the aforementioned fabric, an analytical solution which facilitates to calculate shielding effectiveness of metal mesh, was taken into consideration. Due to the physical similarity between the fabric geometry and metal mesh structure, the values of fabric characteristics were substituted in analytical solution. A statistical approach showed that the measured SE results of plain weave composite fabric fitted in the analytical solution for metal mesh in 1.82–2.6 GHz frequency range with strength of 30–36 dB. Thus, depending on desired shielding efficiency the physical texture of shielding fabric can be determined analytically.","PeriodicalId":16556,"journal":{"name":"Journal of Microwave Power and Electromagnetic Energy","volume":"4 1","pages":"245 - 253"},"PeriodicalIF":1.5,"publicationDate":"2020-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85609640","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-07-02DOI: 10.1080/08327823.2020.1794721
P. Mande, N. Sekar
Abstract Microwave-assisted hydrodistillation and conventional hydrodistillation (MAHD and HD) were used for a comparative study of extraction Callistemon citrinus Skeels leaf essential oils. The time required for a MAHD method is 75 minutes that for HD method is 3.5 hours, so MAHD requires lesser time. The increases in yield of extracted oil by MAHD (0.84%) is found compared oil extracted by HD (0.6%). Essential oils were examined by GC–MS. MAHD extracted essential oils were wealthier in oxygenated molecules. The main constituent was 1, 8-cineole, followed by α-pinene in the case of MAHD. Percentage of the major component increases from 80% to 90% as compared to HD. Their antibacterial activity was examined on ‘Gram-negative’ and ‘Gram-positive bacteria’. In the case of both bacteria, MAHD extracted oil shows better activity than HD extracted one. Antioxidant action was studied by using 2, 2-diphenyl-1-picrylhydrazyl (DPPH•) radical scavenging and β-carotene/linoleic acid assay it is shown that MAHD extract has better activity than HD extract. Surface morphology of Callistemon leaves was studied with scanning electronic microscopy (SEM) which reveals that the MAHD leaves surface undergo major damage to the conventional HD.
{"title":"Comparison of chemical composition, antioxidant and antibacterial activity of Callistemon citrinus skeels (bottlebrush) essential oil obtained by conventional and microwave-assisted hydrodistillation","authors":"P. Mande, N. Sekar","doi":"10.1080/08327823.2020.1794721","DOIUrl":"https://doi.org/10.1080/08327823.2020.1794721","url":null,"abstract":"Abstract Microwave-assisted hydrodistillation and conventional hydrodistillation (MAHD and HD) were used for a comparative study of extraction Callistemon citrinus Skeels leaf essential oils. The time required for a MAHD method is 75 minutes that for HD method is 3.5 hours, so MAHD requires lesser time. The increases in yield of extracted oil by MAHD (0.84%) is found compared oil extracted by HD (0.6%). Essential oils were examined by GC–MS. MAHD extracted essential oils were wealthier in oxygenated molecules. The main constituent was 1, 8-cineole, followed by α-pinene in the case of MAHD. Percentage of the major component increases from 80% to 90% as compared to HD. Their antibacterial activity was examined on ‘Gram-negative’ and ‘Gram-positive bacteria’. In the case of both bacteria, MAHD extracted oil shows better activity than HD extracted one. Antioxidant action was studied by using 2, 2-diphenyl-1-picrylhydrazyl (DPPH•) radical scavenging and β-carotene/linoleic acid assay it is shown that MAHD extract has better activity than HD extract. Surface morphology of Callistemon leaves was studied with scanning electronic microscopy (SEM) which reveals that the MAHD leaves surface undergo major damage to the conventional HD.","PeriodicalId":16556,"journal":{"name":"Journal of Microwave Power and Electromagnetic Energy","volume":"54 1","pages":"230 - 244"},"PeriodicalIF":1.5,"publicationDate":"2020-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83022677","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-07-02DOI: 10.1080/08327823.2020.1794725
Linbao Wei, Weiqiang Qiu, Yingshan Jin, Ruilin Zheng, K. Row, Yudong Cheng, Yinzhe Jin
Abstract The effects of different drying methods (hot air drying (HAD), microwave drying (MD), and hot air-microwave combined drying (HAMCD) processes) on the drying characteristics, rehydration ability, colour, texture, moisture state, microstructure, and energy characteristics of tilapia fillets have been investigated. The best rehydration and recovery ratios of tilapia fillets were obtained using HAMCD (58.96 and 39.24%, respectively). Tilapia fillets quickly become a burnt-yellow colour by MD. HAMCD can improve the hardness, chewiness, and elasticity values, and can obtain crispy tilapia fillets. In the moisture state peak image, the symmetry of the T21 (fixed water) peak obtained at 70 °C + 250 W (H3M) was the best with an asymmetry factor (As) of 1.04. In the MRI image, the brightness of the proton density weighted image was arranged from high to low as follows: HAD > HAMCD > MD. Using SEM, the microstructure of the tilapia fillets prepared using HAMCD showed a large number of small holes. The specific energy consumption was reduced ∼1.8 fold and the thermal efficiency increased ∼5 fold using HAMCD when compared with the HAD process. It was concluded that HAMCD can be used for to process tilapia fillets with high quality and low operating costs.
摘要研究了热风干燥(HAD)、微波干燥(MD)和热风-微波复合干燥(HAMCD)工艺对罗非鱼鱼片干燥特性、复水化能力、色泽、质地、水分状态、微观结构和能量特性的影响。采用HAMCD对罗非鱼鱼片的复水率和回收率最高，分别为58.96和39.24%。经MD处理后，罗非鱼鱼片迅速呈焦黄色。hammcd能提高罗非鱼鱼片的硬度、嚼劲和弹性值，并能得到酥脆的罗非鱼鱼片。在水分状态峰图像中，70°C + 250 W (H3M)条件下获得的T21(固定水)峰的对称性最好，不对称系数(As)为1.04。在MRI图像中，质子密度加权图像亮度由高到低排列为:HAD > HAMCD > MD。利用SEM对HAMCD制备的罗非鱼鱼片进行微观结构分析，发现鱼片表面存在大量小孔。与HAD工艺相比，使用HAMCD的比能耗降低了1.8倍，热效率提高了5倍。结果表明，HAMCD可用于罗非鱼鱼片的高质量加工和低成本生产。
{"title":"Effects of different drying methods on quality changes and energy characteristics of tilapia fillets","authors":"Linbao Wei, Weiqiang Qiu, Yingshan Jin, Ruilin Zheng, K. Row, Yudong Cheng, Yinzhe Jin","doi":"10.1080/08327823.2020.1794725","DOIUrl":"https://doi.org/10.1080/08327823.2020.1794725","url":null,"abstract":"Abstract The effects of different drying methods (hot air drying (HAD), microwave drying (MD), and hot air-microwave combined drying (HAMCD) processes) on the drying characteristics, rehydration ability, colour, texture, moisture state, microstructure, and energy characteristics of tilapia fillets have been investigated. The best rehydration and recovery ratios of tilapia fillets were obtained using HAMCD (58.96 and 39.24%, respectively). Tilapia fillets quickly become a burnt-yellow colour by MD. HAMCD can improve the hardness, chewiness, and elasticity values, and can obtain crispy tilapia fillets. In the moisture state peak image, the symmetry of the T21 (fixed water) peak obtained at 70 °C + 250 W (H3M) was the best with an asymmetry factor (As) of 1.04. In the MRI image, the brightness of the proton density weighted image was arranged from high to low as follows: HAD > HAMCD > MD. Using SEM, the microstructure of the tilapia fillets prepared using HAMCD showed a large number of small holes. The specific energy consumption was reduced ∼1.8 fold and the thermal efficiency increased ∼5 fold using HAMCD when compared with the HAD process. It was concluded that HAMCD can be used for to process tilapia fillets with high quality and low operating costs.","PeriodicalId":16556,"journal":{"name":"Journal of Microwave Power and Electromagnetic Energy","volume":"28 1","pages":"186 - 209"},"PeriodicalIF":1.5,"publicationDate":"2020-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74521702","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-07-02DOI: 10.1080/08327823.2020.1794723
U. Gautam, T. Rawat, Apoorva Aggarwal, D. Upadhyay
Abstract This paper presents a stable, accurate and wideband microwave fractional order differentiator (MFOD) based on infinite impulse response filter. The fractional order differentiator (FOD) design problem is formulated in the z-domain. This formulation alliances with the transmission line elements in cascading. Real coded genetic algorithm (RCGA), particle swarm optimization (PSO) and cuckoo search algorithm (CSA) are applied to determine the optimum values of the characteristic impedances of the transmission line elements. The performance measure criterion of CSA algorithm as compared with other nature inspired algorithms-based differentiator are carried by the magnitude response, absolute magnitude error, phase response, pole-zero response, percentage improvement graph and convergence rate. The simulation and statistical analysis clearly affirm that the proposed MFOD using CSA outperforms RCGA and PSO in all state-of-the-art. The absolute magnitude error for the designed fifth order is as low as 2.9022. The designed fractional order differentiator is implemented in the form of microstrip on RT/Duroid substrate with dielectric constant 2.2 and thickness 0.762 mm. that is eligible for wideband microwave differentiator. The proposed design is compact in size and has low absolute magnitude error over the entire bandwidth. The measured result agrees well with the simulated result in the frequency range 1–12.5 GHz in MATLAB and advanced design software (ADS) environment.
{"title":"Optimal design of compact microwave fractional order differentiator","authors":"U. Gautam, T. Rawat, Apoorva Aggarwal, D. Upadhyay","doi":"10.1080/08327823.2020.1794723","DOIUrl":"https://doi.org/10.1080/08327823.2020.1794723","url":null,"abstract":"Abstract This paper presents a stable, accurate and wideband microwave fractional order differentiator (MFOD) based on infinite impulse response filter. The fractional order differentiator (FOD) design problem is formulated in the z-domain. This formulation alliances with the transmission line elements in cascading. Real coded genetic algorithm (RCGA), particle swarm optimization (PSO) and cuckoo search algorithm (CSA) are applied to determine the optimum values of the characteristic impedances of the transmission line elements. The performance measure criterion of CSA algorithm as compared with other nature inspired algorithms-based differentiator are carried by the magnitude response, absolute magnitude error, phase response, pole-zero response, percentage improvement graph and convergence rate. The simulation and statistical analysis clearly affirm that the proposed MFOD using CSA outperforms RCGA and PSO in all state-of-the-art. The absolute magnitude error for the designed fifth order is as low as 2.9022. The designed fractional order differentiator is implemented in the form of microstrip on RT/Duroid substrate with dielectric constant 2.2 and thickness 0.762 mm. that is eligible for wideband microwave differentiator. The proposed design is compact in size and has low absolute magnitude error over the entire bandwidth. The measured result agrees well with the simulated result in the frequency range 1–12.5 GHz in MATLAB and advanced design software (ADS) environment.","PeriodicalId":16556,"journal":{"name":"Journal of Microwave Power and Electromagnetic Energy","volume":"90 1","pages":"210 - 229"},"PeriodicalIF":1.5,"publicationDate":"2020-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80302092","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-04-02DOI: 10.1080/08327823.2020.1755484
Aswini Harindran, V. Madhurima
Abstract There are five stages in acid coagulation of milk and most studies miss out on a stage or two depending on the experiments performed. Dielectric studies of milk and various physico-chemical studies on the formation of yogurt are well studied and established. However, most of the papers deal with either a limited range of frequencies in the dielectric studies and hence are unable to reflect all the mechanisms of coagulation that occur, or are done as stand-alone experiments, with no correlations to other physico-chemical processes. In this paper, we discuss the broadband dielectric spectroscopy of lactic-acid coagulation of milk, identify the various stages, and compare it with pH, zeta potential, particle size and microscopy. We establish the superiority of dielectric spectroscopy in the identification of all stages of coagulation, the indifference of the process to fat content. Further a strong correlation between tan δ and pH is seen, that is an indicator of the five different stages of lactic-acid induced coagulation. Penetration depth is calculated as milk coagulates and it is seen to be decreasing with coagulation. Broadband dielectric spectroscopy is seen to reveal the onset of coagulation much earlier than other experimental techniques discussed here.
{"title":"On the efficacy of dielectric spectroscopy in the identification of onset of the various stages in lactic acid coagulation of milk","authors":"Aswini Harindran, V. Madhurima","doi":"10.1080/08327823.2020.1755484","DOIUrl":"https://doi.org/10.1080/08327823.2020.1755484","url":null,"abstract":"Abstract There are five stages in acid coagulation of milk and most studies miss out on a stage or two depending on the experiments performed. Dielectric studies of milk and various physico-chemical studies on the formation of yogurt are well studied and established. However, most of the papers deal with either a limited range of frequencies in the dielectric studies and hence are unable to reflect all the mechanisms of coagulation that occur, or are done as stand-alone experiments, with no correlations to other physico-chemical processes. In this paper, we discuss the broadband dielectric spectroscopy of lactic-acid coagulation of milk, identify the various stages, and compare it with pH, zeta potential, particle size and microscopy. We establish the superiority of dielectric spectroscopy in the identification of all stages of coagulation, the indifference of the process to fat content. Further a strong correlation between tan δ and pH is seen, that is an indicator of the five different stages of lactic-acid induced coagulation. Penetration depth is calculated as milk coagulates and it is seen to be decreasing with coagulation. Broadband dielectric spectroscopy is seen to reveal the onset of coagulation much earlier than other experimental techniques discussed here.","PeriodicalId":16556,"journal":{"name":"Journal of Microwave Power and Electromagnetic Energy","volume":"18 1","pages":"161 - 181"},"PeriodicalIF":1.5,"publicationDate":"2020-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74283915","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-04-02DOI: 10.1080/08327823.2020.1755481
Guichao Xiong, Huacheng Zhu, K. Huang, Yang Yang, Zhipeng Fan, Jinghua Ye
Abstract This work aims to improve the uniformity and efficiency of microwave heating. A dual-port simulation model based on the finite element method was built, and two pins were applied to the heating cavity. The impact of dual frequency and pins on the coefficient of variation (COV) and heating efficiency were investigated. The results demonstrated that the uniformity of dual-frequency heating can be improved by 15.4%. Moreover dual-frequency with double pins can maximally increase heating efficiency to 166.7% and the COV value can be reduced to 60.2%, compared with single-frequency heating. The heating effect of other materials was also analyzed. The uniform and efficient microwave heating were realized at dual frequency with pins.
{"title":"The impact of pins on dual-port microwave heating uniformity and efficiency with dual frequency","authors":"Guichao Xiong, Huacheng Zhu, K. Huang, Yang Yang, Zhipeng Fan, Jinghua Ye","doi":"10.1080/08327823.2020.1755481","DOIUrl":"https://doi.org/10.1080/08327823.2020.1755481","url":null,"abstract":"Abstract This work aims to improve the uniformity and efficiency of microwave heating. A dual-port simulation model based on the finite element method was built, and two pins were applied to the heating cavity. The impact of dual frequency and pins on the coefficient of variation (COV) and heating efficiency were investigated. The results demonstrated that the uniformity of dual-frequency heating can be improved by 15.4%. Moreover dual-frequency with double pins can maximally increase heating efficiency to 166.7% and the COV value can be reduced to 60.2%, compared with single-frequency heating. The heating effect of other materials was also analyzed. The uniform and efficient microwave heating were realized at dual frequency with pins.","PeriodicalId":16556,"journal":{"name":"Journal of Microwave Power and Electromagnetic Energy","volume":"50 1","pages":"83 - 98"},"PeriodicalIF":1.5,"publicationDate":"2020-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88242534","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-04-02DOI: 10.1080/08327823.2020.1755480
Mongkolchai Kampagdee, N. Poomsa-ad, L. Wiset
Abstract The thin layer drying of Eri silkworm pupae using microwaves combined with hot air was conducted. Several empirical models simulating thin layer drying of Eri silkworm pupae were selected and analyzed. Microwave power between 100 and 200 W and drying temperatures between 50 and 70°C were used in the study. The comparison between experimental results and those of the models indicated that the Page’s model was the best predictor for the thin layer drying of silkworm pupae. In addition color measurements showed that L* values increase with increased microwave power. The best drying condition of Eri silkworm pupae was also, found at microwave power of 200 W combined with the hot air at the temperature of 50°C.
{"title":"Model for drying of Eri silkworm pupae with microwave and hot air combination","authors":"Mongkolchai Kampagdee, N. Poomsa-ad, L. Wiset","doi":"10.1080/08327823.2020.1755480","DOIUrl":"https://doi.org/10.1080/08327823.2020.1755480","url":null,"abstract":"Abstract The thin layer drying of Eri silkworm pupae using microwaves combined with hot air was conducted. Several empirical models simulating thin layer drying of Eri silkworm pupae were selected and analyzed. Microwave power between 100 and 200 W and drying temperatures between 50 and 70°C were used in the study. The comparison between experimental results and those of the models indicated that the Page’s model was the best predictor for the thin layer drying of silkworm pupae. In addition color measurements showed that L* values increase with increased microwave power. The best drying condition of Eri silkworm pupae was also, found at microwave power of 200 W combined with the hot air at the temperature of 50°C.","PeriodicalId":16556,"journal":{"name":"Journal of Microwave Power and Electromagnetic Energy","volume":"63 1","pages":"110 - 124"},"PeriodicalIF":1.5,"publicationDate":"2020-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74367270","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-04-02DOI: 10.1080/08327823.2020.1758496
Juan Antonio Aguilar Garib
Ancient technology was aimed to manufacture tools and other devices using materials chosen due to their good structural properties. Toughness was an important criterion, but with invention of new artefacts led to greater requirements so that new materials were sought. The problem was that available materials in nature did not fulfil such needs, hence it was no longer a matter of materials choice, but materials engineering. In some cases different materials can be joined to enhance the properties of the system, having composites such as the mud brick made of a mixture of mud reinforced with straw, or processing them, metallurgy for instance, so that new manufactured items were either added or replaced those made of stone and clay. The specifications of the material are higher with each new application and now there are cases where strength, refractoriness, corrosion resistance and density, among others, are required at the same time, exceeding by far the possibilities of traditional materials. Mechanical resistance, density and refractoriness are properties that can be recognized qualitatively, better known than electrochemical and functional properties of materials. The latter allows the construction of semiconductors that are an engineering challenge since intrinsic semiconductors found in nature exhibit properties below the electronic industry requirements, while enhance is not a matter of superposition of materials for having additive properties. The properties are modified by adding dopant agents and conduct thermal treatments. That is, they are designed to have properties that are beyond (meta in Greek) those found in natural occurring materials. Although the term metamaterial is a way to make a distinction from other advancements in materials science and engineering, the modern reference to them considers “exotic” interaction with electromagnetic waves. Metamaterials are designed in size, shape and combination of different materials that can be stacked to form periodical arrangements, smaller than the wavelength. The list of applications is long; one that seems like science fiction is the invisibility cloak, by bending the wave propagation around an object, and that has been proven with some degree of success. The possibility for metamaterials to manipulate electromagnetic, and mechanical, waves, according to their wavelength, makes them attractive for fabricating small, high gain antennas for communication purposes. The wavelength is in the order of centimeters, large enough to prepare metamaterials for this application by mechanical assembling of periodical arrangements of rings and wires based on theoretical designs. There is a great number of documents dedicated to metamaterials for small antennas in different applications. Although in many cases they are related to microwaves, those documents are often addressed to the design and tests, sometimes virtual, of the fabricated devices for communication applications. In the case of shorter
{"title":"Editor’s message: microwave processing of modern materials","authors":"Juan Antonio Aguilar Garib","doi":"10.1080/08327823.2020.1758496","DOIUrl":"https://doi.org/10.1080/08327823.2020.1758496","url":null,"abstract":"Ancient technology was aimed to manufacture tools and other devices using materials chosen due to their good structural properties. Toughness was an important criterion, but with invention of new artefacts led to greater requirements so that new materials were sought. The problem was that available materials in nature did not fulfil such needs, hence it was no longer a matter of materials choice, but materials engineering. In some cases different materials can be joined to enhance the properties of the system, having composites such as the mud brick made of a mixture of mud reinforced with straw, or processing them, metallurgy for instance, so that new manufactured items were either added or replaced those made of stone and clay. The specifications of the material are higher with each new application and now there are cases where strength, refractoriness, corrosion resistance and density, among others, are required at the same time, exceeding by far the possibilities of traditional materials. Mechanical resistance, density and refractoriness are properties that can be recognized qualitatively, better known than electrochemical and functional properties of materials. The latter allows the construction of semiconductors that are an engineering challenge since intrinsic semiconductors found in nature exhibit properties below the electronic industry requirements, while enhance is not a matter of superposition of materials for having additive properties. The properties are modified by adding dopant agents and conduct thermal treatments. That is, they are designed to have properties that are beyond (meta in Greek) those found in natural occurring materials. Although the term metamaterial is a way to make a distinction from other advancements in materials science and engineering, the modern reference to them considers “exotic” interaction with electromagnetic waves. Metamaterials are designed in size, shape and combination of different materials that can be stacked to form periodical arrangements, smaller than the wavelength. The list of applications is long; one that seems like science fiction is the invisibility cloak, by bending the wave propagation around an object, and that has been proven with some degree of success. The possibility for metamaterials to manipulate electromagnetic, and mechanical, waves, according to their wavelength, makes them attractive for fabricating small, high gain antennas for communication purposes. The wavelength is in the order of centimeters, large enough to prepare metamaterials for this application by mechanical assembling of periodical arrangements of rings and wires based on theoretical designs. There is a great number of documents dedicated to metamaterials for small antennas in different applications. Although in many cases they are related to microwaves, those documents are often addressed to the design and tests, sometimes virtual, of the fabricated devices for communication applications. In the case of shorter ","PeriodicalId":16556,"journal":{"name":"Journal of Microwave Power and Electromagnetic Energy","volume":"9 1","pages":"81 - 82"},"PeriodicalIF":1.5,"publicationDate":"2020-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87608432","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-04-02DOI: 10.1080/08327823.2020.1755482
D. C. Campos
Abstract The use of polyols as green solvents in conjunction with microwave heating (MH) has become a very attractive synthetic protocol nowadays. However, among the needs of this area, as well as any other that uses MH, figure the electromagnetic properties of the materials. In this context, the contribution of this work is provide dielectric data of three polyols: glycerol, 1,2-propanediol and 1,3-propanediol. The data are presented in two ways: in frequency domain and in temperature domain (whose parameters were denominated f-dispersion and T-dispersion, respectively). In the frequency domain analysis, f-dispersion parameters were obtained for the Cole–Davidson model – one of Debye's models. From the analysis in this domain, the uncertainty and accuracy of the data was established. In the temperature domain analysis, an empirical model is proposed to represent the complex permittivity as a function of temperature – ɛ*(T) of the polyols. From the analysis in this domain, concluded that the presented model can be applied to other materials. In addition, that can to conclude that the phenomena of thermal runaway and self-limitation of heating are, in fact, subsequent opposite phenomena associated to the variation of the loss factor with the temperature.
{"title":"Dielectric properties of polyols, at frequency range 0.2–3 GHz and temperature range 293–473 K: an analysis in the frequency and temperature domain","authors":"D. C. Campos","doi":"10.1080/08327823.2020.1755482","DOIUrl":"https://doi.org/10.1080/08327823.2020.1755482","url":null,"abstract":"Abstract The use of polyols as green solvents in conjunction with microwave heating (MH) has become a very attractive synthetic protocol nowadays. However, among the needs of this area, as well as any other that uses MH, figure the electromagnetic properties of the materials. In this context, the contribution of this work is provide dielectric data of three polyols: glycerol, 1,2-propanediol and 1,3-propanediol. The data are presented in two ways: in frequency domain and in temperature domain (whose parameters were denominated f-dispersion and T-dispersion, respectively). In the frequency domain analysis, f-dispersion parameters were obtained for the Cole–Davidson model – one of Debye's models. From the analysis in this domain, the uncertainty and accuracy of the data was established. In the temperature domain analysis, an empirical model is proposed to represent the complex permittivity as a function of temperature – ɛ*(T) of the polyols. From the analysis in this domain, concluded that the presented model can be applied to other materials. In addition, that can to conclude that the phenomena of thermal runaway and self-limitation of heating are, in fact, subsequent opposite phenomena associated to the variation of the loss factor with the temperature.","PeriodicalId":16556,"journal":{"name":"Journal of Microwave Power and Electromagnetic Energy","volume":"58 1","pages":"125 - 160"},"PeriodicalIF":1.5,"publicationDate":"2020-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90987227","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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