The C01-xMnxFez04 （0 ≤ x 〈-5 0.5） ferrite system is synthesized by using an auto combustion technique using metal nitrates. The influence of Mn substitution on the structural, electrical, impedance and magnetic pr...The C01-xMnxFez04 （0 ≤ x 〈-5 0.5） ferrite system is synthesized by using an auto combustion technique using metal nitrates. The influence of Mn substitution on the structural, electrical, impedance and magnetic properties of cobalt ferrite is reported. X-ray diffraction patterns of the prepared samples confirm that the Bragg＇s peak belongs to a spinel cubic crystal structure. The lattice constant of cobalt ferrite increases with the increase in Mn content. The microstructural study is carried out by using the SEM technique and the average grain size continues to increase with increasing manganese content. AC conductivity analysis suggests that the conduction is due to small polaron hopping. DC electrical resistivity decreases with increasing temperature for a Col-xMnxFe204 system showing semiconducting behavior. The activation energy is found to be higher in the paramagnetic region than the ferromagnetic region. Curie temperature decreases with Mn substitution in the host ferrite system. Dielectric dispersion having Maxwell-Wagner-type interfacial polarization has been observed for cobalt ferrite samples. Magnetic properties have been studied by measuring M-H plots. The saturation and remanent magnetization increases with Mn substitution.展开更多
The present article deals with filtration of seawater to remove sodium chloride(NaCl)using filter made from organized structures of carbon nanotubes(CNTs).The filter consists of hollow carbon cylinder(length~10 cm,dia...The present article deals with filtration of seawater to remove sodium chloride(NaCl)using filter made from organized structures of carbon nanotubes(CNTs).The filter consists of hollow carbon cylinder(length~10 cm,diameter~1 cm),which is composed of radially aligned CNTs.This carbon hollow cylinder has been synthesized by continuous spray pyrolysis of ferrocene–benzene solution in argon atmosphere.The hollow cylinder has been turned into a water filter by closing one end and keeping a small funnel at the other.Filtration of seawater(Marina Beach,Chennai,India)has been obtained both under the self pressure of seawater column in the hollow cylinder and under the difference of pressure created by enclosing the filter in a vacuum tight container.It has been found that the efficiency of filtration is about two times higher under partial vacuum(~10–2 torr)created on the filtrate(water)side.After filtration of seawater,a deposit in the inner surface of hollow cylinder has been found.This deposit has been characterized by X-ray diffraction,transmission electron microscopy and energy dispersive X-ray analysis,and it has been found that the deposit was NaCl.The filtration leads to almost complete removal of NaCl from the seawater.展开更多
Recently a lot of medical tablets with special packets in the global market are available. For the safety and purity of the tablet, we need to scan it by developed scanner technology, which should be not more expensiv...Recently a lot of medical tablets with special packets in the global market are available. For the safety and purity of the tablet, we need to scan it by developed scanner technology, which should be not more expensive and easily available in the market. The THz technology is one of them. In the proposed work, we have tasted tablet images with the help of the THz super-resolution scanner, which is already available in our lab. The AI machine learning data concept has been investigated. Good resolution of images has been obtained. Furthermore, the challenging research problems are discussed. Finally, it summarizes the recent updates in terahertz technology for drug inspection and medical applications with potential research challenges.展开更多
The study on artificial intelligence(AI) methods for tuning of particle accelerators has been reported in many literatures.This paper presents tuning method for agent-based control systems of transport lines in the ca...The study on artificial intelligence(AI) methods for tuning of particle accelerators has been reported in many literatures.This paper presents tuning method for agent-based control systems of transport lines in the case of sensor/actuator failures.The method uses model-based tracking concept to relax the demand on sensor data.The condition for successful operation of the stated scheme is derived,and the concept is demonstrated through simulation by applying it to the model of microtron,transport line-1 and booster of indus accelerator.The results show that this approach is very effective in transport line control during sensor/actuator failures.展开更多
This Letter tackles the issue of non-contact detection of ultrasonic fields by utilizing a novel optical method based on the parametric indirect microscopic imaging(PIMI) technique. A general theoretical model describ...This Letter tackles the issue of non-contact detection of ultrasonic fields by utilizing a novel optical method based on the parametric indirect microscopic imaging(PIMI) technique. A general theoretical model describing the three-dimensional anisotropic photoelastic effect in solid was developed. The mechanism of polarization status variations of light passing through the stress and strain fields was analyzed. Non-contact measurements of the ultrasonic field propagating in an isotropic quartz glass have been fulfilled by the PIMI technique under different ultrasonic excitation conditions. PIMI parameters such as sin δ, Φ, and the Stokes parameters have been found to be sensitive to ultrasonic fields.展开更多
This paper addresses a computationally compact and statistically optimal joint Maximum a Posteriori(MAP)algorithm for channel estimation and data detection in the presence of Phase Noise(PHN)in iterative Orthogonal Fr...This paper addresses a computationally compact and statistically optimal joint Maximum a Posteriori(MAP)algorithm for channel estimation and data detection in the presence of Phase Noise(PHN)in iterative Orthogonal Frequency Division Multiplexing(OFDM)receivers used for high speed and high spectral efficient wireless communication systems.The MAP cost function for joint estimation and detection is derived and optimized further with the proposed cyclic gradient descent optimization algorithm.The proposed joint estimation and detection algorithm relaxes the restriction of small PHN assumptions and utilizes the prior statistical knowledge of PHN spectral components to produce a statistically optimal solution.The frequency-domain estimation of Channel Transfer Function(CTF)in frequency selective fading makes the method simpler,compared with the estimation of Channel Impulse Response(CIR)in the time domain.Two different time-varying PHN models,produced by Free Running Oscillator(FRO)and Phase-Locked Loop(PLL)oscillator,are presented and compared for performance difference with proposed OFDM receiver.Simulation results for joint MAP channel estimation are compared with Cramer-Rao Lower Bound(CRLB),and the simulation results for joint MAP data detection are compared with“NO PHN"performance to demonstrate that the proposed joint MAP estimation and detection algorithm achieve near-optimum performance even under multipath channel fading.展开更多
This paper presents the tri-band slot loaded patch antenna for mobile communication. The antenna consists of parallel slots loaded circular disk with defected ground structure antenna (DGS). The antenna without DGS, a...This paper presents the tri-band slot loaded patch antenna for mobile communication. The antenna consists of parallel slots loaded circular disk with defected ground structure antenna (DGS). The antenna without DGS, acts like wide band antenna and bandwidth is 34.45% (3.47 - 4.92 GHz) with maximum gain of 4.97 dBi, which can be used in WiMax application. This structure has the following advantages: 1) co-axial feeding technique, which is very simple as compared to other feeding technique, 2) simple and cost effective and 3) it is more efficient than the antenna without DGS. This antenna has been analyzed using IE3D simulation software.展开更多
This paper repotts an experimental investigation of the flow field inside a low aspect ratio dump combustor.The length of the combustor studied was less than the reattachment length for the separated flow.The exit of ...This paper repotts an experimental investigation of the flow field inside a low aspect ratio dump combustor.The length of the combustor studied was less than the reattachment length for the separated flow.The exit of the combustor is tapered which supports the flow reversal from the exit section.The flow field behaviour in the combustor is evaluated from pressure and velocity measurement studies.The velocity,stream function and pressure distribution inside the combustor are used to elucidate the presence of recircu lation and flow reversal from the exit section of the combustor for different Reynolds numbers.A small variation in Ums velocity was observed in axial direction while in the radial direction it was quite high.Two recirculation zones are recognized and the strength of the recirculation was seen to increase with flow Reynolds number.The turbulence intensity in the recirculation and shear layer zone was seen to be higher than the potential core.展开更多
The inhibition effect of synthesized diethyl 3,4-bis（4-methoxybenzylideneamino） thieno[2,3-b] thiophene-2,5- dicarboxylate （Inh I） and diethyl 3,4-bis（benzylideneamino） thieno[2,3-b] thiophene-2,5-dicarboxylate ...The inhibition effect of synthesized diethyl 3,4-bis（4-methoxybenzylideneamino） thieno[2,3-b] thiophene-2,5- dicarboxylate （Inh I） and diethyl 3,4-bis（benzylideneamino） thieno[2,3-b] thiophene-2,5-dicarboxylate （Inh II）, on cor- rosion of mild steel in 15% HC1 solution was investigated using weight loss measurements, electrochemical polarization, and electrochemical impedance spectroscopy techniques. The experimental results show that the inhibition efficiency of studied inhibitors increased with the increase of inhibitors concentration but decreased with the increase of temperature. Corrosion inhibition efficiencies of 94.5% and 92.1% were obtained with 250 ppm of Inh I and Inh II at 303 K, respectively. The potentiodynamic polarization measurements indicate that the studied inhibitors act as mixed inhibitor. The thermodynamic parameters of the corrosion and adsorption processes were calculated and evaluated. The adsorption of these inhibitors was found to obey Langmuir adsorption isotherm. Scanning electron microscopy was used to characterize the surface morphology of the mild steel specimens in presence and absence of inhibitors. The mechanism of the inhibition process was discussed in the light of the chemical structure and quantum-chemical calculations of the investigated inhibitors.展开更多
This paper is concerned with the flow of two immiscible fluids through a porous horizontal channel. The fluid in the upper region is the micropolar fluid/the Eringen fluid, and the fluid in the lower region is the New...This paper is concerned with the flow of two immiscible fluids through a porous horizontal channel. The fluid in the upper region is the micropolar fluid/the Eringen fluid, and the fluid in the lower region is the Newtonian viscous fluid. The flow is driven by a constant pressure gradient. The presence of micropolar fluids introduces additional rotational parameters. Also, the porous material considered in both regions has two different permeabilities. A direct method is used to obtain the analytical solu- tion of the concerned problem. In the present problem, the effects of the couple stress, the micropolarity parameter, the viscosity ratio, and the permeability on the velocity profile and the microrotational velocity are discussed. It is found that all the physical parameters play an important role in controlling the translational velocity profile and the microrotational velocity. In addition, numerical values of the different flow parameters are computed. The effects of the different flow parameters on the flow rate and the wall shear stress are also discussed graphically.展开更多
The problem of the creeping flow through a spherical droplet with a non-homogenous porous layer in a spherical container has been studied analytically.Darcy’s model for the flow inside the porous annular region and t...The problem of the creeping flow through a spherical droplet with a non-homogenous porous layer in a spherical container has been studied analytically.Darcy’s model for the flow inside the porous annular region and the Stokes equation for the flow inside the spherical cavity and container are used to analyze the flow.The drag force is exerted on the porous spherical particles enclosing a cavity,and the hydrodynamic permeability of the spherical droplet with a non-homogeneous porous layer is calculated.Emphasis is placed on the spatially varying permeability of a porous medium,which is not covered in all the previous works related to spherical containers.The variation of hydrodynamic permeability and the wall effect with respect to various flow parameters are presented and discussed graphically.The streamlines are presented to discuss the kinematics of the flow.Some previous results for hydrodynamic permeability and drag forces have been verified as special limiting cases.展开更多
基金the UGC-DSA-I, DSTPURSE and DST-FIST-II programs for financial support
文摘The C01-xMnxFez04 （0 ≤ x 〈-5 0.5） ferrite system is synthesized by using an auto combustion technique using metal nitrates. The influence of Mn substitution on the structural, electrical, impedance and magnetic properties of cobalt ferrite is reported. X-ray diffraction patterns of the prepared samples confirm that the Bragg＇s peak belongs to a spinel cubic crystal structure. The lattice constant of cobalt ferrite increases with the increase in Mn content. The microstructural study is carried out by using the SEM technique and the average grain size continues to increase with increasing manganese content. AC conductivity analysis suggests that the conduction is due to small polaron hopping. DC electrical resistivity decreases with increasing temperature for a Col-xMnxFe204 system showing semiconducting behavior. The activation energy is found to be higher in the paramagnetic region than the ferromagnetic region. Curie temperature decreases with Mn substitution in the host ferrite system. Dielectric dispersion having Maxwell-Wagner-type interfacial polarization has been observed for cobalt ferrite samples. Magnetic properties have been studied by measuring M-H plots. The saturation and remanent magnetization increases with Mn substitution.
基金grateful to the Department of Science and Technology(DST),Nano Science Mission scheme and Ministry of New and Renewable Energy(MNRE)India for financial support.
文摘The present article deals with filtration of seawater to remove sodium chloride(NaCl)using filter made from organized structures of carbon nanotubes(CNTs).The filter consists of hollow carbon cylinder(length~10 cm,diameter~1 cm),which is composed of radially aligned CNTs.This carbon hollow cylinder has been synthesized by continuous spray pyrolysis of ferrocene–benzene solution in argon atmosphere.The hollow cylinder has been turned into a water filter by closing one end and keeping a small funnel at the other.Filtration of seawater(Marina Beach,Chennai,India)has been obtained both under the self pressure of seawater column in the hollow cylinder and under the difference of pressure created by enclosing the filter in a vacuum tight container.It has been found that the efficiency of filtration is about two times higher under partial vacuum(~10–2 torr)created on the filtrate(water)side.After filtration of seawater,a deposit in the inner surface of hollow cylinder has been found.This deposit has been characterized by X-ray diffraction,transmission electron microscopy and energy dispersive X-ray analysis,and it has been found that the deposit was NaCl.The filtration leads to almost complete removal of NaCl from the seawater.
文摘Recently a lot of medical tablets with special packets in the global market are available. For the safety and purity of the tablet, we need to scan it by developed scanner technology, which should be not more expensive and easily available in the market. The THz technology is one of them. In the proposed work, we have tasted tablet images with the help of the THz super-resolution scanner, which is already available in our lab. The AI machine learning data concept has been investigated. Good resolution of images has been obtained. Furthermore, the challenging research problems are discussed. Finally, it summarizes the recent updates in terahertz technology for drug inspection and medical applications with potential research challenges.
文摘The study on artificial intelligence(AI) methods for tuning of particle accelerators has been reported in many literatures.This paper presents tuning method for agent-based control systems of transport lines in the case of sensor/actuator failures.The method uses model-based tracking concept to relax the demand on sensor data.The condition for successful operation of the stated scheme is derived,and the concept is demonstrated through simulation by applying it to the model of microtron,transport line-1 and booster of indus accelerator.The results show that this approach is very effective in transport line control during sensor/actuator failures.
基金supported by the National Key Research and Development Program of China(No.2017YFF0107100)the National Natural Science Foundation of China(NSFC)(Nos.61501239 and 51805268)+3 种基金the NSFC International Young Scientist Research Fund(No.61750110520)China Postdoctoral Science Foundation(No.2017M621745)Overseas Expertise Introduction Project for Discipline Innovation(111 Project)Zijin Professor Project of Nanjing University of Science and Technology
文摘This Letter tackles the issue of non-contact detection of ultrasonic fields by utilizing a novel optical method based on the parametric indirect microscopic imaging(PIMI) technique. A general theoretical model describing the three-dimensional anisotropic photoelastic effect in solid was developed. The mechanism of polarization status variations of light passing through the stress and strain fields was analyzed. Non-contact measurements of the ultrasonic field propagating in an isotropic quartz glass have been fulfilled by the PIMI technique under different ultrasonic excitation conditions. PIMI parameters such as sin δ, Φ, and the Stokes parameters have been found to be sensitive to ultrasonic fields.
文摘This paper addresses a computationally compact and statistically optimal joint Maximum a Posteriori(MAP)algorithm for channel estimation and data detection in the presence of Phase Noise(PHN)in iterative Orthogonal Frequency Division Multiplexing(OFDM)receivers used for high speed and high spectral efficient wireless communication systems.The MAP cost function for joint estimation and detection is derived and optimized further with the proposed cyclic gradient descent optimization algorithm.The proposed joint estimation and detection algorithm relaxes the restriction of small PHN assumptions and utilizes the prior statistical knowledge of PHN spectral components to produce a statistically optimal solution.The frequency-domain estimation of Channel Transfer Function(CTF)in frequency selective fading makes the method simpler,compared with the estimation of Channel Impulse Response(CIR)in the time domain.Two different time-varying PHN models,produced by Free Running Oscillator(FRO)and Phase-Locked Loop(PLL)oscillator,are presented and compared for performance difference with proposed OFDM receiver.Simulation results for joint MAP channel estimation are compared with Cramer-Rao Lower Bound(CRLB),and the simulation results for joint MAP data detection are compared with“NO PHN"performance to demonstrate that the proposed joint MAP estimation and detection algorithm achieve near-optimum performance even under multipath channel fading.
文摘This paper presents the tri-band slot loaded patch antenna for mobile communication. The antenna consists of parallel slots loaded circular disk with defected ground structure antenna (DGS). The antenna without DGS, acts like wide band antenna and bandwidth is 34.45% (3.47 - 4.92 GHz) with maximum gain of 4.97 dBi, which can be used in WiMax application. This structure has the following advantages: 1) co-axial feeding technique, which is very simple as compared to other feeding technique, 2) simple and cost effective and 3) it is more efficient than the antenna without DGS. This antenna has been analyzed using IE3D simulation software.
基金This project is sponsored by ISRO and Space Technology Cell at Indian Institute of Technology,Kanpur.Mr.N.K.Gupta of LPSC is the project coordinator at ISRO。
文摘This paper repotts an experimental investigation of the flow field inside a low aspect ratio dump combustor.The length of the combustor studied was less than the reattachment length for the separated flow.The exit of the combustor is tapered which supports the flow reversal from the exit section.The flow field behaviour in the combustor is evaluated from pressure and velocity measurement studies.The velocity,stream function and pressure distribution inside the combustor are used to elucidate the presence of recircu lation and flow reversal from the exit section of the combustor for different Reynolds numbers.A small variation in Ums velocity was observed in axial direction while in the radial direction it was quite high.Two recirculation zones are recognized and the strength of the recirculation was seen to increase with flow Reynolds number.The turbulence intensity in the recirculation and shear layer zone was seen to be higher than the potential core.
文摘The inhibition effect of synthesized diethyl 3,4-bis（4-methoxybenzylideneamino） thieno[2,3-b] thiophene-2,5- dicarboxylate （Inh I） and diethyl 3,4-bis（benzylideneamino） thieno[2,3-b] thiophene-2,5-dicarboxylate （Inh II）, on cor- rosion of mild steel in 15% HC1 solution was investigated using weight loss measurements, electrochemical polarization, and electrochemical impedance spectroscopy techniques. The experimental results show that the inhibition efficiency of studied inhibitors increased with the increase of inhibitors concentration but decreased with the increase of temperature. Corrosion inhibition efficiencies of 94.5% and 92.1% were obtained with 250 ppm of Inh I and Inh II at 303 K, respectively. The potentiodynamic polarization measurements indicate that the studied inhibitors act as mixed inhibitor. The thermodynamic parameters of the corrosion and adsorption processes were calculated and evaluated. The adsorption of these inhibitors was found to obey Langmuir adsorption isotherm. Scanning electron microscopy was used to characterize the surface morphology of the mild steel specimens in presence and absence of inhibitors. The mechanism of the inhibition process was discussed in the light of the chemical structure and quantum-chemical calculations of the investigated inhibitors.
基金supported by the Science and Engineering Research Board,New Delhi(No.SR/FTP/MS-47/2012)
文摘This paper is concerned with the flow of two immiscible fluids through a porous horizontal channel. The fluid in the upper region is the micropolar fluid/the Eringen fluid, and the fluid in the lower region is the Newtonian viscous fluid. The flow is driven by a constant pressure gradient. The presence of micropolar fluids introduces additional rotational parameters. Also, the porous material considered in both regions has two different permeabilities. A direct method is used to obtain the analytical solu- tion of the concerned problem. In the present problem, the effects of the couple stress, the micropolarity parameter, the viscosity ratio, and the permeability on the velocity profile and the microrotational velocity are discussed. It is found that all the physical parameters play an important role in controlling the translational velocity profile and the microrotational velocity. In addition, numerical values of the different flow parameters are computed. The effects of the different flow parameters on the flow rate and the wall shear stress are also discussed graphically.
基金Project supported by the Science and Engineering Research Board,New Delhi(No.SR/FTP/MS-47/2012)。
文摘The problem of the creeping flow through a spherical droplet with a non-homogenous porous layer in a spherical container has been studied analytically.Darcy’s model for the flow inside the porous annular region and the Stokes equation for the flow inside the spherical cavity and container are used to analyze the flow.The drag force is exerted on the porous spherical particles enclosing a cavity,and the hydrodynamic permeability of the spherical droplet with a non-homogeneous porous layer is calculated.Emphasis is placed on the spatially varying permeability of a porous medium,which is not covered in all the previous works related to spherical containers.The variation of hydrodynamic permeability and the wall effect with respect to various flow parameters are presented and discussed graphically.The streamlines are presented to discuss the kinematics of the flow.Some previous results for hydrodynamic permeability and drag forces have been verified as special limiting cases.
