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Welding characteristics of butt-welded Inconel625 plate using CO2 laser beam
摘要： Inconel weldments are widely used in automobile and structural industries. In this study, the joints of Inconel625 are made with CO2 Laser beam welding process. The experimentation is carried out with two sets of process parameters varying the laser power and estimating the response of the welded component. Radiography analysis and distortion in the weldments are carried out. Distortion is measured using the Vernier height gauge. The lower the better-quality characteristics are chosen for distortion. The welds are free from flaws and the lower heat input results in the lower distortion.
关键词： Radiography,Distortion,Laser beam welding,Inconel625,Bead geometry
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Epitaxial GaP grown on Silicon by MEE and MBE Techniques as a Pathway for Dilute Nitride-Si Tandem Solar Cells
摘要： For long-wavelength space-based radars, such as the P-band radar on the recently selected European Space Agency BIOMASS mission, system distortions (crosstalk and channel imbalance), Faraday rotation, and system noise all combine to degrade the measurements. A first-order analysis of these effects on the measurements of the polarimetric scattering matrix is used to derive differentiable expressions for the errors in the polarimetric backscattering coefficients in the presence of Faraday rotation. Both the amplitudes and phases of the distortion terms are shown to be important in determining the errors and their maximum values. Exact simulations confirm the accuracy and predictions of the first-order analysis. Under an assumed power-law relation between σhv and the biomass, the system distortions and noise are converted into biomass estimation errors, and it is shown that the magnitude of the deviation of the channel imbalance from unity must be 4–5 dB less than the crosstalk, or it will dominate the error in the biomass. For uncalibrated data and midrange values of biomass, the crosstalk must be less than ?24 dB if the maximum possible error in the biomass is to be within 20% of its true value. A less stringent condition applies if the amplitudes and phases of the distortion terms are considered random since errors near the maximum possible are very unlikely. For lower values of the biomass, the noise becomes increasingly important because the σhv signal-to-noise ratio is smaller.
关键词： Biomass,Faraday rotation,polarimetric measurements,system distortion,calibration,long-wavelength radar
更新于2025-09-19 17:13:59
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[IEEE 2019 Workshop on Recent Advances in Photonics (WRAP) - Guwahati, India (2019.12.13-2019.12.14)] 2019 Workshop on Recent Advances in Photonics (WRAP) - Stand-off Femtosecond Laser Induced Breakdown Spectroscopy of Metals, Soil, Plastics and Classification Studies
摘要： This paper presents one of the first studies of the harmonic impact of a significantly large photovoltaic (PV) solar farm of 20 MW in a utility distribution system. This solar farm is a constituent of the 80-MW PV solar farm in Sarnia, Ontario, which is so far the largest solar farm in Canada. The utility network is modeled in detail using the commercial grade PSCAD/EMTDC software, which is validated through load flow studies conducted by CYME software and correlated with SCADA measurements. The validated network model is used for network resonance study and harmonics impact analysis of the solar farms under different network conditions. The harmonics data instrumented for several months were provided by the transmission utility at the two solar farm units and at the main feeder substation. These data were utilized for extensive harmonic impact studies with widely different short-circuit levels and network resonance conditions. This paper presents the detailed procedure adopted for performing such harmonic impact studies. It is concluded that this large solar farm may not cause any substantial voltage distortion on the distribution network during steady-state operating conditions. However, recommendations are made for utilities to perform such studies to ensure the safe operation of critical loads.
关键词： network resonance,total harmonic distortion,solar energy,harmonics,Distribution systems,total demand distortion,photovoltaic (PV) solar system,frequency scan
更新于2025-09-16 10:30:52
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Disturbances Generated by Lighting Systems with LED Lamps and the Reduction in Their Impacts
摘要： The paper deals with electromagnetic disturbances in the form of current higher harmonics, which are generated by LED lighting elements. It presents the problems related to the formation and impact of higher harmonics in the electrical systems of commercial facilities. The results of tests and analyses of current distortions for two di?erent LED lamps are included, and these are in reference to the parameters set out in the normal applicable standards. A system was then proposed to improve the quality of energy in the mains of commercial facilities in the form of a two-stage power supply. Tests of the systems with the aforementioned LED lamps were conducted and commented upon after introduction of the two-stage power supply. The ?nal part of the paper contains a summary of the obtained test results.
关键词： electromagnetic compatibility,total harmonic distortion (THD),LED lamp,two-stage power supply,current and voltage distortion,lighting system,power factor correction (PFC),higher harmonics
更新于2025-09-16 10:30:52
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[IEEE 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Huangshan, China (2019.8.5-2019.8.8)] 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Research on the Gain Saturation Induced Noise in an Optical Fiber Sensing System
摘要： In an optical fiber sensing time division multiplexing (TDM) system, when the optical pulse with high peak power and low repetition rates is boost amplified, it is prone to be gain saturation and pulse distortion. The paper analysed their effects on the intensity and phase noises, and the results show that the pulse distortion induced noise is mainly down-converted relative intensity noise (RIN) lines spectra caused by the gain jitter. Then the RIN lines are converted into corresponding phase noise lines by the interferometer, which finally cause false signals in the sensor system. However in the case of saturated gain and pulse distortion, the increase of noise background is insignificant. Basing on the above results, several noise suppression schemes have been proposed, which will provide guidance for the design of large-scale remote sensing systems in the future.
关键词： Pulse distortion,Gain saturation,Relative intensity noise,Phase noise,Optical fiber sensor
更新于2025-09-16 10:30:52
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Computation and Communication Technologies || Implementation of Multilevel Z-Source Inverter using Solar Photovoltaic Energy system for Hybrid Electric Vehicles
摘要： This paper extends a topology for cascaded multilevel Z source inverter employs of z source inverter unit block with bidirectional switches. The conventional z source inverter consist network impedance with multiple indictors and capacitors arranged Z type topology performs either buck or boost the input voltage for non linear load depending upon duty ratio and modulation index in a multiple stage conversion with the help of impedance source passive network (L and C Z source inverter reduces harmonic distortion and overcomes limitations of conventional inverters. The proposed multilevel Z source inverter reduces harmonics further and provides a novel topology for power conversion. Capability of proposed configuration in producing all odd and even output voltage level source with input to the power source and increase the power efficiency is proved by simulation result for 3-level inverter. The output of the proposed system is simulated using MATLAB-SIMULINK and implemented in real simulation hardware for electric vehicles using dSPIC controller.
关键词： MATLAB,dSPIC,multilevel z-source inverter,ZSI,total harmonic distortion
更新于2025-09-16 10:30:52
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Extreme learning machine-based receiver for MIMO LED communications
摘要： This work concerns receiver design for light-emitting diode (LED) multiple input multiple output (MIMO) communications where the LED nonlinearity can severely degrade the performance of communications. We firstly propose an extreme learning machine (ELM) based receiver to jointly handle the LED nonlinearity and cross-LED interference. Then, by taking advantage of the features of the ELM, we propose to use a circulant structure for the input weight matrix and the fast Fourier transform (FFT) for implementation, leading to significant computational complexity reduction. It is demonstrated that, the proposed ELM based receivers can handle the nonlinearity and interference much more effectively compared to conventional techniques, and the low complexity ELM-based receiver with circulant input matrix delivers almost the same performance as the receiver based on the conventional ELM.
关键词： Extreme learning machine,Nonlinearity,Post-distortion,Feedforward neural networks,LED communications
更新于2025-09-16 10:30:52
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[IEEE 2019 IEEE PES Innovative Smart Grid Technologies Conference - Latin America (ISGT Latin America) - Gramado, Brazil (2019.9.15-2019.9.18)] 2019 IEEE PES Innovative Smart Grid Technologies Conference - Latin America (ISGT Latin America) - Analysis of Harmonic Distortion on Low Voltage Distribution Systems with Electric Vehicles and Photovoltaic Systems
摘要： Power electronic interfacing based devices, such as photovoltaic systems and electric vehicles chargers cause harmonic distortion on the power grid. This has been an increasing concern, especially in low voltage residential systems as these devices are becoming common and expected to be largely integrated into distribution systems. In this context, this paper focuses on a harmonic analysis based on daily simulations considering loads and generation pro?les with characteristics spectra of harmonics for residential loads, photovoltaic systems and electric vehicle chargers. Effects on the grid will depend on the phase angles of each harmonic component, distortion indexes will not behave in a simple additive way due to the variety of connected devices.
关键词： harmonic distortion,electric vehicles,Distribution systems,photovoltaic systems,low voltage
更新于2025-09-16 10:30:52
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Effect of Inter-Layer Dwell Time on Distortion and Residual Stresses of Laser Metal Deposited Wall
摘要： The laser metal deposition is an advanced manufacturing technology enabling the production of large-sized parts and partially or completely elimination of machining and welding. The process is characterised by a non-uniform local heating of the buildup leading to a stress distribution, which may exceed the yield strength of the material and leads to loss of dimensional accuracy. The interlayer dwell time has a strong influence on the temperature field. The effect of the interlayer dwell time on the distortion and the stress distribution during laser metal deposition of a single-pass wall on the edge of 2 mm thick plate was studied experimentally and numerically. The deposited material was IN625 and the substrate material was AISI 316. A decrease of the residual displacement, due to a uniform shrinkage after the deposition of the last layer and a lower level of the residual compressive longitudinal plastic strain, has been observed in the studies without a dwell time. The peak increment of the free edge displacement corresponds to the first layer and hence the subsequent layers will be deposited on the already plastically deformed buildup. The tensile residual longitudinal stress near the top of the buildup and transverse stress near the edges of the buildup is higher than yield strength in the studies with dwell time.
关键词： Temperature field,Laser metal deposition,Residual stresses,Simulation,Distortion
更新于2025-09-16 10:30:52
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[IEEE 2019 Third International Conference on Intelligent Computing in Data Sciences (ICDS) - Marrakech, Morocco (2019.10.28-2019.10.30)] 2019 Third International Conference on Intelligent Computing in Data Sciences (ICDS) - Photovoltaic Interfaced Shunt Active Power Filter Under Online-Varying Parameters Based On Fuzzy Logic Controller And Adaptive Hysteresis Band Current Controller
摘要： This paper explores performances of the photo-voltaic plant associated with shunt active power ?lter (PV-SAPF). The model guarantees uninterrupted power quality, with the bene?t of PV power injection. In order to improve the PV-SAPF dynamics and to reduce harmonic current distortion, the control of the proposed system is based on: 1) instantaneous PQ strategy for reference harmonic term identi?cation, 2) fuzzy logic controller for the Maximum power point tracking MPPT of the PV, 3) fuzzy logic based controller for DC capacitor voltage regulation, and 4) adaptive hysteresis current controller (AHCC) for the switching signals of the PV-SAPF system. The suggested control is performed in a Matlab/Simulink environment and compared with the conventional one using P& O algorithm, proportional integral controller and a ?xed hysteresis band controller. The results show that the proposed control adapted to PV-SAPF gives low value of total harmonic distortion THD and better dynamic performance in terms of references tracking under abrupt variation of the functioning point of the nonlinear load while applying a variable PV irradiance pro?le.
关键词： Fuzzy logic controller (FLC),Adaptive hysteresis current controller (AHCC),PV-SAPF,Dynamic performance,Total harmonic distortion (THD)
更新于2025-09-16 10:30:52