For the first time in the world advanced multi layered Red Mud and MWCNTs (ARMC) based EMI shielding material has been developed at CSIR-AMPRI, Bhopal. Red mud provides oxides of titanium and iron as precursor and the...For the first time in the world advanced multi layered Red Mud and MWCNTs (ARMC) based EMI shielding material has been developed at CSIR-AMPRI, Bhopal. Red mud provides oxides of titanium and iron as precursor and the MWCNTs provides electrical conductivity characteristics necessary for making desired EMI shielding materials. The novel process involves unique designing of chemical compositions and mineralogical phases of red mud, MWCNTs together with appropriate additive and solvent which results in the simultaneous and synergistic chemical reactions among various constituents thereby forming tailored precursor powder. Further, the ceramic processing of tailored precursor powder in appropriate environment enables formation of advanced ARMC shielding material having a variety of ceramic phases with multi elemental compositions and multi layered crystal structures. The synthesized material was characterized by various techniques namely XRD, PL, FESEM, EDXA. The reflection loss (R. L.) of the sample was calculated based on the measured complex permittivity and permeability. The advanced ARMC material with thickness t = 1.5 mm showed a minimum R. L. of -35.5 Db at 14.0 GHz with a response band width of 1.8 GHz. Thus, the developed advanced ARMC material acts as a good EMI wave absorber.展开更多
Two hybrid processes including ozonation-ceramic membrane-biological activated carbon （BAC） （Process A） and ceramic membrane-BAC （Process B） were compared to treat polluted raw water. The performance of hybrid p...Two hybrid processes including ozonation-ceramic membrane-biological activated carbon （BAC） （Process A） and ceramic membrane-BAC （Process B） were compared to treat polluted raw water. The performance of hybrid processes was evaluated with the removal efficiencies of turbidity, ammonia and organic matter. The results indicated that more than 99% of particle count was removed by both hybrid processes and ozonation had no significant effect on its removal. BAC filtration greatly improved the removal of ammonia. Increasing the dissolved oxygen to 30.0 mg/L could lead to a removal of ammonia with concentrations as high as 7.80 mg/L and 8.69 mg/L for Processes A and B, respectively. The average removal efficiencies of total organic carbon and ultraviolet absorbance at 254 nm （UV254, a parameter indicating organic matter with aromatic structure） were 49% and 52% for Process A, 51% and 48% for Process B, respectively. Some organic matter was oxidized by ozone and this resulted in reduced membrane fouling and increased membrane flux by 25%-30%. However, pre-ozonation altered the components of the raw water and affected the microorganisms in the BAC, which may impact the removals of organic matter and nitrite negatively.展开更多
In this work, the results of a study of laser ablation cleaning process on ceramic artifacts are presented. The experiments were conducted on a ＂Carosello＂, a structural hollow element made of clay, placed in arches...In this work, the results of a study of laser ablation cleaning process on ceramic artifacts are presented. The experiments were conducted on a ＂Carosello＂, a structural hollow element made of clay, placed in arches, in domes or even in the walls of buildings such as churches and houses. Our results show that laser ablation techniques is able to remove the surface impurity patina from artifacts surface without changes the chemical composition and the optical properties of ceramic. Moreover, because the laser cleaning heats only locally the surface of the sample, this method don＇t preclude the possibility to apply on artifact the thermo-luminescence dating process.展开更多
Perfl uorosulfonic acid/ceramic nanocomposite membranes were investigated as electrolytes for polymer electrolyte membrane fuel cell applications under low relative humidity. Different nanosized ceramics（SiO2, ZrO2, ...Perfl uorosulfonic acid/ceramic nanocomposite membranes were investigated as electrolytes for polymer electrolyte membrane fuel cell applications under low relative humidity. Different nanosized ceramics（SiO2, ZrO2, TiO2） with diameters in the range of 2-6 nm were synthesized in situ in Nafion solution through a sol-gel process and the formed nanosized ceramics were well-dispersed in the solution.The nanocomposite membranes were formed through a casting process. The nanocomposite membrane showes enhanced water retention ability and improved proton conductivity compared to those of pure Nafi on membrane. The mechanical strength of the formed nanocomposite membranes is slightly less than that of pure Nafi on membrane. The experimental results demonstrate that the polymer ceramic nanocompsite membranes are potential electrolyte for fuel cells operating at elevated temperature.展开更多
This paper presents a new type of ultra-material microwave pressure sensor designed for extreme environments,and conducts a systematic study on its structural design,manufacturing process,working mechanism,and experim...This paper presents a new type of ultra-material microwave pressure sensor designed for extreme environments,and conducts a systematic study on its structural design,manufacturing process,working mechanism,and experimental performance.The sensor is based on the cross-slot ultra-material resonant structure.Platinum-based conductive patterns are precisely fabricated on a high-purity alumina ceramic substrate through screen printing,and a strong bond between metal and ceramic is achieved through high-temperature sintering.Thanks to the high-temperature stability of the ceramic material and the high precision of the process,this sensor maintains excellent structural integrity and performance consistency in harsh environments.The working mechanism of the sensor is based on the microstructural deformation induced by pressure.When external pressure is applied to the ceramic cavity,the deformation of the cavity will change the equivalent electromagnetic boundary conditions inside,thereby causing perturbations in the resonant modes of the metamaterial,resulting in a continuous measurable shift in the resonant frequency.Based on this mechanism,the change in pressure can be precisely mapped to the frequency change,enabling wireless and passive pressure measurement.By utilizing the intrinsic resonant radiation of the metamaterial to achieve coupled readings,the complexity of sensor integration is significantly reduced and its working reliability in high-pressure,high-temperature,and strong electromagnetic interference environments is improved.During the design stage,the influence laws of the geometric parameters of the metamaterial and other factors on the resonant performance and pressure sensitivity were analyzed through finite element coupling simulation.Experimental verification shows that the sensor exhibits excellent linear pressure response within the range of 0−500 kPa,and maintains good repeatability and frequency stability in the high-pressure zone.The maximum sensitivity reaches 135 kHz/kPa,and the frequency drift is minimal during multiple loading-unloading cycles,fully demonstrating that the structural strength and reliability of the design meet the engineering requirements.The sensor proposed in this study could achieve longterm stable operation in aerospace engine compartments,high-temperature metallurgical furnaces,deep mine pressure monitoring,petrochemical high-corrosion pipelines,and extreme environment equipment.This research not only demonstrated the potential of integrating metamaterials with advanced ceramic processes to construct wireless passive sensors,but also provided new design ideas and process routes for the engineering application of microwave sensing technology in harsh environments.展开更多
The development of efficient components to save energy plays an important role in designing of sustainable solutions. Based on the concept of green energy, gas burners based on porous ceramic structures are interestin...The development of efficient components to save energy plays an important role in designing of sustainable solutions. Based on the concept of green energy, gas burners based on porous ceramic structures are interesting technologies to supply heat and lighting by burning even low calorific fuels as biogas. In this work, perspectives on development of porous ceramic burners in Brazil are presented. For this study a mixture of rare earth oxides―yttria (YTR) was selected as raw material, considering the unique luminescence proprieties of rare earth elements. Ceramic nettings with homogeneous morphology were produced by colloidal processing of rare earth powders. The results highlighted the potentiality of these components to be applied as biogas burners.展开更多
A kind of circular ring high frequency wideband underwater acoustic transducer is developed by using the Low Q value and broadband characteristics of the piezoelectricity composite material,and the dual mode coupling ...A kind of circular ring high frequency wideband underwater acoustic transducer is developed by using the Low Q value and broadband characteristics of the piezoelectricity composite material,and the dual mode coupling is used to broaden the bandwidth of the transducer by double ring stacking along the axial direction.Through theoretical analysis and simulation calculation,the geometric dimensions of the sensitive components are determined.The piezoelectric composite rings are processed and then the stack sensitive element can be made by stacking two piezoelectric composite rings with the same outer diameter and different thickness in axial direction by cutting piezoelectric ceramicsfilling the flexible polymer-coating electrode.Finally,the transducer can be made by pouring waterproof sound-permeable layer.The performances of transducer have also been tested in the water and the test results show that the resonant frequency is 410 kHz,the maximum transmit voltage response is 150 dB,the-3 dB bandwidth can reaches 60 kHz,the horizontal directivity（-5 dB） is 360°,and the vertical directivity（-3 dB） is 20°.It is also shown that the bandwidth of the transducer can be enlarged remarkably by using the method of stacking two different thickness piezoelectric composite rings along the axial direction,and the horizontal omnidirectional emission of acoustic wave can be realized展开更多
文摘For the first time in the world advanced multi layered Red Mud and MWCNTs (ARMC) based EMI shielding material has been developed at CSIR-AMPRI, Bhopal. Red mud provides oxides of titanium and iron as precursor and the MWCNTs provides electrical conductivity characteristics necessary for making desired EMI shielding materials. The novel process involves unique designing of chemical compositions and mineralogical phases of red mud, MWCNTs together with appropriate additive and solvent which results in the simultaneous and synergistic chemical reactions among various constituents thereby forming tailored precursor powder. Further, the ceramic processing of tailored precursor powder in appropriate environment enables formation of advanced ARMC shielding material having a variety of ceramic phases with multi elemental compositions and multi layered crystal structures. The synthesized material was characterized by various techniques namely XRD, PL, FESEM, EDXA. The reflection loss (R. L.) of the sample was calculated based on the measured complex permittivity and permeability. The advanced ARMC material with thickness t = 1.5 mm showed a minimum R. L. of -35.5 Db at 14.0 GHz with a response band width of 1.8 GHz. Thus, the developed advanced ARMC material acts as a good EMI wave absorber.
基金supported by the National Grand Water Project(No.2008ZX07423-002)the National Natural Science Foundation of China(No.50978170)the Guangdong Provincial Funding(No.2012B030800001)
文摘Two hybrid processes including ozonation-ceramic membrane-biological activated carbon （BAC） （Process A） and ceramic membrane-BAC （Process B） were compared to treat polluted raw water. The performance of hybrid processes was evaluated with the removal efficiencies of turbidity, ammonia and organic matter. The results indicated that more than 99% of particle count was removed by both hybrid processes and ozonation had no significant effect on its removal. BAC filtration greatly improved the removal of ammonia. Increasing the dissolved oxygen to 30.0 mg/L could lead to a removal of ammonia with concentrations as high as 7.80 mg/L and 8.69 mg/L for Processes A and B, respectively. The average removal efficiencies of total organic carbon and ultraviolet absorbance at 254 nm （UV254, a parameter indicating organic matter with aromatic structure） were 49% and 52% for Process A, 51% and 48% for Process B, respectively. Some organic matter was oxidized by ozone and this resulted in reduced membrane fouling and increased membrane flux by 25%-30%. However, pre-ozonation altered the components of the raw water and affected the microorganisms in the BAC, which may impact the removals of organic matter and nitrite negatively.
文摘In this work, the results of a study of laser ablation cleaning process on ceramic artifacts are presented. The experiments were conducted on a ＂Carosello＂, a structural hollow element made of clay, placed in arches, in domes or even in the walls of buildings such as churches and houses. Our results show that laser ablation techniques is able to remove the surface impurity patina from artifacts surface without changes the chemical composition and the optical properties of ceramic. Moreover, because the laser cleaning heats only locally the surface of the sample, this method don＇t preclude the possibility to apply on artifact the thermo-luminescence dating process.
基金Funded by the Postdoctoral Science Foundation of China(2013M540610)the Hubei Province Scientific Research Projects(D20131601)
文摘Perfl uorosulfonic acid/ceramic nanocomposite membranes were investigated as electrolytes for polymer electrolyte membrane fuel cell applications under low relative humidity. Different nanosized ceramics（SiO2, ZrO2, TiO2） with diameters in the range of 2-6 nm were synthesized in situ in Nafion solution through a sol-gel process and the formed nanosized ceramics were well-dispersed in the solution.The nanocomposite membranes were formed through a casting process. The nanocomposite membrane showes enhanced water retention ability and improved proton conductivity compared to those of pure Nafi on membrane. The mechanical strength of the formed nanocomposite membranes is slightly less than that of pure Nafi on membrane. The experimental results demonstrate that the polymer ceramic nanocompsite membranes are potential electrolyte for fuel cells operating at elevated temperature.
基金supported by Key Research and Development Plan of Shanxi Province(Nos.202102030201005,202203021222022)National Natural Science Foundation of China(No.62401522)+2 种基金Fundamental Research of Shanxi Province(No.202203021222070)China Postdoctoral Science Foundation(No.2023M743313)Research Project Supported by Shanxi Scholarship Council of China.
文摘This paper presents a new type of ultra-material microwave pressure sensor designed for extreme environments,and conducts a systematic study on its structural design,manufacturing process,working mechanism,and experimental performance.The sensor is based on the cross-slot ultra-material resonant structure.Platinum-based conductive patterns are precisely fabricated on a high-purity alumina ceramic substrate through screen printing,and a strong bond between metal and ceramic is achieved through high-temperature sintering.Thanks to the high-temperature stability of the ceramic material and the high precision of the process,this sensor maintains excellent structural integrity and performance consistency in harsh environments.The working mechanism of the sensor is based on the microstructural deformation induced by pressure.When external pressure is applied to the ceramic cavity,the deformation of the cavity will change the equivalent electromagnetic boundary conditions inside,thereby causing perturbations in the resonant modes of the metamaterial,resulting in a continuous measurable shift in the resonant frequency.Based on this mechanism,the change in pressure can be precisely mapped to the frequency change,enabling wireless and passive pressure measurement.By utilizing the intrinsic resonant radiation of the metamaterial to achieve coupled readings,the complexity of sensor integration is significantly reduced and its working reliability in high-pressure,high-temperature,and strong electromagnetic interference environments is improved.During the design stage,the influence laws of the geometric parameters of the metamaterial and other factors on the resonant performance and pressure sensitivity were analyzed through finite element coupling simulation.Experimental verification shows that the sensor exhibits excellent linear pressure response within the range of 0−500 kPa,and maintains good repeatability and frequency stability in the high-pressure zone.The maximum sensitivity reaches 135 kHz/kPa,and the frequency drift is minimal during multiple loading-unloading cycles,fully demonstrating that the structural strength and reliability of the design meet the engineering requirements.The sensor proposed in this study could achieve longterm stable operation in aerospace engine compartments,high-temperature metallurgical furnaces,deep mine pressure monitoring,petrochemical high-corrosion pipelines,and extreme environment equipment.This research not only demonstrated the potential of integrating metamaterials with advanced ceramic processes to construct wireless passive sensors,but also provided new design ideas and process routes for the engineering application of microwave sensing technology in harsh environments.
基金The State of Sao Paulo Research Foundation(FAPESP)and The National Council for Scientific and Technological Development(CNPq)for financial supportin addition,Coordination of High Degree People Improvement(CAPES)for scholarship support of the student Silas Cardoso dos Santos.
文摘The development of efficient components to save energy plays an important role in designing of sustainable solutions. Based on the concept of green energy, gas burners based on porous ceramic structures are interesting technologies to supply heat and lighting by burning even low calorific fuels as biogas. In this work, perspectives on development of porous ceramic burners in Brazil are presented. For this study a mixture of rare earth oxides―yttria (YTR) was selected as raw material, considering the unique luminescence proprieties of rare earth elements. Ceramic nettings with homogeneous morphology were produced by colloidal processing of rare earth powders. The results highlighted the potentiality of these components to be applied as biogas burners.
基金supported by the National Natural Science Foundation of China(614710470)
文摘A kind of circular ring high frequency wideband underwater acoustic transducer is developed by using the Low Q value and broadband characteristics of the piezoelectricity composite material,and the dual mode coupling is used to broaden the bandwidth of the transducer by double ring stacking along the axial direction.Through theoretical analysis and simulation calculation,the geometric dimensions of the sensitive components are determined.The piezoelectric composite rings are processed and then the stack sensitive element can be made by stacking two piezoelectric composite rings with the same outer diameter and different thickness in axial direction by cutting piezoelectric ceramicsfilling the flexible polymer-coating electrode.Finally,the transducer can be made by pouring waterproof sound-permeable layer.The performances of transducer have also been tested in the water and the test results show that the resonant frequency is 410 kHz,the maximum transmit voltage response is 150 dB,the-3 dB bandwidth can reaches 60 kHz,the horizontal directivity（-5 dB） is 360°,and the vertical directivity（-3 dB） is 20°.It is also shown that the bandwidth of the transducer can be enlarged remarkably by using the method of stacking two different thickness piezoelectric composite rings along the axial direction,and the horizontal omnidirectional emission of acoustic wave can be realized
