In order to improve the quality of 3D printed raspberry preserves after post-processing,microwave ovens combining infrared and microwave methods were utilized.The effects of infrared heating temperature,infrared heati...In order to improve the quality of 3D printed raspberry preserves after post-processing,microwave ovens combining infrared and microwave methods were utilized.The effects of infrared heating temperature,infrared heating time,microwave power,microwave heating time on the center temperature,moisture content,the chroma(C*),the total color difference(ΔE*),shape fidelity,hardness,and the total anthocyanin content of 3D printed raspberry preserves were analyzed by response surface method(RSM).The results showed that under combining with the two methods,infrared heating improved the fidelity and quality degradation of printed products,while microwave heating enhanced the efficiency of infrared heating.Infrared-microwave combination cooking could maintain relatively stable color appearance and shape of 3D printed raspberry preserves.The AHP–CRITIC hybrid weighting method combined with the response surface test to determine the comprehensive weights of the evaluation indicators optimized the process parameters,and the optimal process parameters were obtained:infrared heating temperature of 190℃,infrared heating time of 10 min and 30 s,microwave power of 300 W,and microwave heating time of 2 min and 6 s.The 3D printed raspberry cooking methods obtained under the optimal conditions seldom had color variation,porous structure,uniform texture,and high shape fidelity,which retained the characteristics of personalized manufacturing by 3D printing.This study could provide a reference for the postprocessing and quality control of 3D cooking methods.展开更多
Chromium ore fines containing coal (COFCC) can be rapidly heated by microwave to conduct the voluminal reduction, which lays a foundation of getting sponge ferrochromium powders with a lower content of C. Under the co...Chromium ore fines containing coal (COFCC) can be rapidly heated by microwave to conduct the voluminal reduction, which lays a foundation of getting sponge ferrochromium powders with a lower content of C. Under the conditions of COFCC with n(O)-n(C) (molar ratio) as 1.00-0.84 and n(SiO2)-n(CaO) as 1.00-0.39, the samples were heated by 10 kW microwave power to reach the given temperatures and held for different times respectively. The results show that the low-C-Cr ferrochromium metal phase in the reduced materials forms before the high-C-Cr ferrochromium metal phase does. With increasing temperature the C content of ferrochromium metals is in a positive correlation with the content of Cr. The C content of ferrochromium metal in reduced materials is 0-10.07% with an average value of 4.68%. With the increase of holding time the Cr content in ferrochromium metals is in a negative correlation with the content of C, while the content of Fe changes in the contrary way. In the microwave field the kinetic conditions of carburization are closely related with the temperature of microwave heating, holding time and carbon fitting ratio.展开更多
Double self-adaptive fuzzy PID algorithm-based control strategy was proposed to construct quasi-cascade control system to control the speed of the acid-pickling process of titanium plates and strips. It is very useful...Double self-adaptive fuzzy PID algorithm-based control strategy was proposed to construct quasi-cascade control system to control the speed of the acid-pickling process of titanium plates and strips. It is very useful in overcoming non-linear dynamic behavior, uncertain and time-varying parameters, un-modeled dynamics, and couples between the automatic turbulence control (ATC) and the automatic acid temperature control (AATC) with varying parameters during the operation process. The quasi-cascade control system of inner and outer loop self-adaptive fuzzy PID controller was built, which could effectively control the pickling speed of plates and strips. The simulated results and real application indicate that the plates and strips acid pickling speed control system has good performances of adaptively tracking the parameter variations and anti-disturbances, which ensures the match of acid pickling temperature and turbulence of flowing with acid pickling speed, improving the surface quality of plates and strips acid pickling, and energy efficiency.展开更多
The exothermic efficiency of microwave heating an electrolyte/water solution is remarkably high due to the dielectric heating by orientation polarization of water and resistance heating by the Joule process occurred s...The exothermic efficiency of microwave heating an electrolyte/water solution is remarkably high due to the dielectric heating by orientation polarization of water and resistance heating by the Joule process occurred simultaneously compared with pure water.A three-dimensional finite element numerical model of multi-feed microwave heating industrial liquids continuously flowing in a meter-scale circular tube is presented.The temperature field inside the applicator tube in the cavity is solved by COMSOL Multiphysics and professional programming to describe the momentum,energy and Maxwell's equations.The evaluations of the electromagnetic field,the temperature distribution and the velocity field are simulated for the fluids dynamically heated by singleand multi-feed microwave system,respectively.Both the pilot experimental investigations and numerical results of microwave with single-feed heating for fluids with different effective permittivity and flow rates show that the presented numerical modeling makes it possible to analyze dynamic process of multi-feed microwave heating the industrial liquid.The study aids in enhancing the understanding and optimizing of dynamic process in the use of multi-feed microwave heating industrial continuous flow for a variety of material properties and technical parameters.展开更多
A new iron-making process using carburized pre-reduced iron ore pellets and microwave heating is investigated. The pre-reduced pellets, with a porous structure, and fine particles are carburized homogeneously at 400-6...A new iron-making process using carburized pre-reduced iron ore pellets and microwave heating is investigated. The pre-reduced pellets, with a porous structure, and fine particles are carburized homogeneously at 400-650 ℃ in a CO atmosphere. The carburized carbon not only acts reaction as a reduction agent, but also absorbs microwave in the reduction process. Hence, the carburized pre-reduced pellets can be rapidly reduced by microwave heating. There are three procedures involved in the process, namely, gas-based pre-reduction, low-temperatttre carburization and deep reduction by microwave heating. Carburized pre-reduced iron ore pellets show a rapid temperature rise that is twice as fast as the results for pre-reduced pellets in the laboratory. This not only improves the efficiency of the microwave heating, but also accelerates the reduction of iron oxides. The temperature of the pre-reduced pellets rises to 1050 ℃ in 45 min when the carburization rate is 2.02%, and the metallization rate and compressive strength reach 94.24% and 1725 N/pellet, respectively.展开更多
The technology that waste activated carbon after extracting gold is regenerated with steam under microwave heating was studied. The influence of the activation temperature, activation duration and steam flow rate on i...The technology that waste activated carbon after extracting gold is regenerated with steam under microwave heating was studied. The influence of the activation temperature, activation duration and steam flow rate on iodine adsorption value and regeneration yield of activated carbon was investigated. The response surface methodology （RSM） technique was utilized to optimize the process conditions. The optimum conditions for the preparation of activated carbon are identified to be activation temperature of 831 ℃, activation duration of 40 min and steam flow rate of 2.67 mL/min. The optimum conditions result in an activated carbon with an iodine number of 1048 mg/g and a yield of 40%, and the BET surface area evaluated using nitrogen adsorption isotherm is 1493 m2/g, with total pore volume of 1.242 cm3/g. And the pore structure of activated carbon regenerated is mainly composed of micropores and a small amount of mesopores.展开更多
To improve heating uniformity and anthocyanin content of the blueberry pulp under microwave heating,the intermittent variable power microwave heating technology was introduced in the study.The effects of technology pa...To improve heating uniformity and anthocyanin content of the blueberry pulp under microwave heating,the intermittent variable power microwave heating technology was introduced in the study.The effects of technology parameters in terms of high microwave intensity heating time,intermittent time,low microwave intensity and low microwave intensity heating time on the blueberry pulp quality parameters(heating uniformity,average moisture content,the highest temperature and anthocyanin content)were investigated by using the response surface method.The results showed that the longer heating time under different microwave intensities resulted in the poorer heating uniformity.The intermittent stage promoted heat and mass transfer within the pulp and reduced the temperature difference and moisture gradient within the pulp,which enhanced desired uniformity of temperature and moisture distribution before entering the low microwave intensity heating stage.Therefore,the longer the intermittent time,the greater the heating uniformity.The optimal parameters were developed as high microwave intensity of 4 W·g^(-1),high microwave intensity heating time of 9.86 min,intermittent time of 10 min,low microwave intensity of 2.2 W·g^(-1)and low microwave intensity heating time of 6 min.This research might provide guidance for microwave heating berry fruits.展开更多
The preparation of microsized hematite powder from ferrous sulfate using microwave calcination was investigated based on the TG/DTG curves. The decomposition of industrial ferrous sulfate under air atmosphere was divi...The preparation of microsized hematite powder from ferrous sulfate using microwave calcination was investigated based on the TG/DTG curves. The decomposition of industrial ferrous sulfate under air atmosphere was divided into three stages, and a ferrous sulfate sample added with 15% Fe_2O_3 could strongly absorb microwave energy. Therefore, preparing hematite powder from ferrous sulfate using microwave calcination was feasible. Hematite was obtained under the following optimized conditions: calcination temperature, 850 °C; microwave power, 650 W; and sample amount, 40 g. The obtained hematite satisfied the first-grade quality requirements. The total ferrum value was more than 58%, and the total sulfur and phosphorus contents were less than 0.5% and 0.2%, respectively. X-ray powder diffraction and scanning electron microscopy were used to characterize the structure and morphology of microsized hematite powder. The particles were non-spherical in shape, and the average particle size distribution was 10.45 μm. This work provides new potential applications for waste ferrous sulfate.展开更多
基金Supported by the National Natural Science Foundation of China(32072352)。
文摘In order to improve the quality of 3D printed raspberry preserves after post-processing,microwave ovens combining infrared and microwave methods were utilized.The effects of infrared heating temperature,infrared heating time,microwave power,microwave heating time on the center temperature,moisture content,the chroma(C*),the total color difference(ΔE*),shape fidelity,hardness,and the total anthocyanin content of 3D printed raspberry preserves were analyzed by response surface method(RSM).The results showed that under combining with the two methods,infrared heating improved the fidelity and quality degradation of printed products,while microwave heating enhanced the efficiency of infrared heating.Infrared-microwave combination cooking could maintain relatively stable color appearance and shape of 3D printed raspberry preserves.The AHP–CRITIC hybrid weighting method combined with the response surface test to determine the comprehensive weights of the evaluation indicators optimized the process parameters,and the optimal process parameters were obtained:infrared heating temperature of 190℃,infrared heating time of 10 min and 30 s,microwave power of 300 W,and microwave heating time of 2 min and 6 s.The 3D printed raspberry cooking methods obtained under the optimal conditions seldom had color variation,porous structure,uniform texture,and high shape fidelity,which retained the characteristics of personalized manufacturing by 3D printing.This study could provide a reference for the postprocessing and quality control of 3D cooking methods.
基金Project(50474083) supported by the National Natural Science Foundation of ChinaProject supported by the Baoshan Iron & Steel Co. Ltd. of China
文摘Chromium ore fines containing coal (COFCC) can be rapidly heated by microwave to conduct the voluminal reduction, which lays a foundation of getting sponge ferrochromium powders with a lower content of C. Under the conditions of COFCC with n(O)-n(C) (molar ratio) as 1.00-0.84 and n(SiO2)-n(CaO) as 1.00-0.39, the samples were heated by 10 kW microwave power to reach the given temperatures and held for different times respectively. The results show that the low-C-Cr ferrochromium metal phase in the reduced materials forms before the high-C-Cr ferrochromium metal phase does. With increasing temperature the C content of ferrochromium metals is in a positive correlation with the content of Cr. The C content of ferrochromium metal in reduced materials is 0-10.07% with an average value of 4.68%. With the increase of holding time the Cr content in ferrochromium metals is in a negative correlation with the content of C, while the content of Fe changes in the contrary way. In the microwave field the kinetic conditions of carburization are closely related with the temperature of microwave heating, holding time and carbon fitting ratio.
基金Project(51090385) supported by the National Natural Science Foundation of ChinaProject(2001IB001) supported by Yunnan Provincial Science and Technology Fund, China
文摘Double self-adaptive fuzzy PID algorithm-based control strategy was proposed to construct quasi-cascade control system to control the speed of the acid-pickling process of titanium plates and strips. It is very useful in overcoming non-linear dynamic behavior, uncertain and time-varying parameters, un-modeled dynamics, and couples between the automatic turbulence control (ATC) and the automatic acid temperature control (AATC) with varying parameters during the operation process. The quasi-cascade control system of inner and outer loop self-adaptive fuzzy PID controller was built, which could effectively control the pickling speed of plates and strips. The simulated results and real application indicate that the plates and strips acid pickling speed control system has good performances of adaptively tracking the parameter variations and anti-disturbances, which ensures the match of acid pickling temperature and turbulence of flowing with acid pickling speed, improving the surface quality of plates and strips acid pickling, and energy efficiency.
基金Project(KKSY201503006)supported by Scientific Research Foundation of Kunming University of Science and Technology,ChinaProject(2014FD009)supported by the Applied Basic Research Foundation(Youth Program)of ChinaProject(51090385)supported by the National Natural Science Foundation of China
文摘The exothermic efficiency of microwave heating an electrolyte/water solution is remarkably high due to the dielectric heating by orientation polarization of water and resistance heating by the Joule process occurred simultaneously compared with pure water.A three-dimensional finite element numerical model of multi-feed microwave heating industrial liquids continuously flowing in a meter-scale circular tube is presented.The temperature field inside the applicator tube in the cavity is solved by COMSOL Multiphysics and professional programming to describe the momentum,energy and Maxwell's equations.The evaluations of the electromagnetic field,the temperature distribution and the velocity field are simulated for the fluids dynamically heated by singleand multi-feed microwave system,respectively.Both the pilot experimental investigations and numerical results of microwave with single-feed heating for fluids with different effective permittivity and flow rates show that the presented numerical modeling makes it possible to analyze dynamic process of multi-feed microwave heating the industrial liquid.The study aids in enhancing the understanding and optimizing of dynamic process in the use of multi-feed microwave heating industrial continuous flow for a variety of material properties and technical parameters.
基金Project(NCET-04-0748)supported by the New Century Excellent Talent Planning of China
文摘A new iron-making process using carburized pre-reduced iron ore pellets and microwave heating is investigated. The pre-reduced pellets, with a porous structure, and fine particles are carburized homogeneously at 400-650 ℃ in a CO atmosphere. The carburized carbon not only acts reaction as a reduction agent, but also absorbs microwave in the reduction process. Hence, the carburized pre-reduced pellets can be rapidly reduced by microwave heating. There are three procedures involved in the process, namely, gas-based pre-reduction, low-temperatttre carburization and deep reduction by microwave heating. Carburized pre-reduced iron ore pellets show a rapid temperature rise that is twice as fast as the results for pre-reduced pellets in the laboratory. This not only improves the efficiency of the microwave heating, but also accelerates the reduction of iron oxides. The temperature of the pre-reduced pellets rises to 1050 ℃ in 45 min when the carburization rate is 2.02%, and the metallization rate and compressive strength reach 94.24% and 1725 N/pellet, respectively.
基金Project(2013AA064003)supported by the National High Technology Research and Development Program of ChinaProject(2012HB008)supported by Young and Middle-aged Academic Technology Leader Backup Talent Cultivation Program in Yunnan Province,China
文摘The technology that waste activated carbon after extracting gold is regenerated with steam under microwave heating was studied. The influence of the activation temperature, activation duration and steam flow rate on iodine adsorption value and regeneration yield of activated carbon was investigated. The response surface methodology （RSM） technique was utilized to optimize the process conditions. The optimum conditions for the preparation of activated carbon are identified to be activation temperature of 831 ℃, activation duration of 40 min and steam flow rate of 2.67 mL/min. The optimum conditions result in an activated carbon with an iodine number of 1048 mg/g and a yield of 40%, and the BET surface area evaluated using nitrogen adsorption isotherm is 1493 m2/g, with total pore volume of 1.242 cm3/g. And the pore structure of activated carbon regenerated is mainly composed of micropores and a small amount of mesopores.
基金Supported by the National Natural Science Foundation of China(32072352)。
文摘To improve heating uniformity and anthocyanin content of the blueberry pulp under microwave heating,the intermittent variable power microwave heating technology was introduced in the study.The effects of technology parameters in terms of high microwave intensity heating time,intermittent time,low microwave intensity and low microwave intensity heating time on the blueberry pulp quality parameters(heating uniformity,average moisture content,the highest temperature and anthocyanin content)were investigated by using the response surface method.The results showed that the longer heating time under different microwave intensities resulted in the poorer heating uniformity.The intermittent stage promoted heat and mass transfer within the pulp and reduced the temperature difference and moisture gradient within the pulp,which enhanced desired uniformity of temperature and moisture distribution before entering the low microwave intensity heating stage.Therefore,the longer the intermittent time,the greater the heating uniformity.The optimal parameters were developed as high microwave intensity of 4 W·g^(-1),high microwave intensity heating time of 9.86 min,intermittent time of 10 min,low microwave intensity of 2.2 W·g^(-1)and low microwave intensity heating time of 6 min.This research might provide guidance for microwave heating berry fruits.
基金Project(2013AA064003)supported by the National Technology Research and Development Program of ChinaProject(51564033)supported by the National Natural Science Foundation of ChinaProject(2016FA023)supported by the Yunnan Applied Basic Research(CNMRCUXT1403)State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization,Kunming University of Science and Technology,China
文摘The preparation of microsized hematite powder from ferrous sulfate using microwave calcination was investigated based on the TG/DTG curves. The decomposition of industrial ferrous sulfate under air atmosphere was divided into three stages, and a ferrous sulfate sample added with 15% Fe_2O_3 could strongly absorb microwave energy. Therefore, preparing hematite powder from ferrous sulfate using microwave calcination was feasible. Hematite was obtained under the following optimized conditions: calcination temperature, 850 °C; microwave power, 650 W; and sample amount, 40 g. The obtained hematite satisfied the first-grade quality requirements. The total ferrum value was more than 58%, and the total sulfur and phosphorus contents were less than 0.5% and 0.2%, respectively. X-ray powder diffraction and scanning electron microscopy were used to characterize the structure and morphology of microsized hematite powder. The particles were non-spherical in shape, and the average particle size distribution was 10.45 μm. This work provides new potential applications for waste ferrous sulfate.
