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Study of Type-B QPOs Observed in Black Hole X-Ray Binary Swift J1728.9-3613

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Research in Astronomy and Astrophysics 2024年第3期24卷 1-9页

作者： Raj Kumar Astrophysical Sciences Division Bhabha Atomic Research CentreMumbai 400085India Homi Bhabha National Institute Mumbai 400094India

We report the detection of type-B quasi-periodic oscillation(QPO)of the black hole X-ray binary Swift J1728.9-3613 observed by NICER during the 2019 outburst.A type-B QPO was observed for the first two days and it disappeared as flux increased,but again appeared at∼7.70 Hz when flux was dramatically *** source was found in the soft intermediate state during these *** further studied the energy dependence of the *** found that QPO was observed only for a higher energy range implying that the origin of QPO is possibly due to the corona emitting higher energy photons by the inverse Compton *** variation of spectral parameters can be explained with the disk truncation *** fractional rms was found to be monotonically increased with *** phase lag spectrum followed the“U-shaped”*** rms and phase lag spectrum are modeled and explained with the single-component Comptonization model vkompthdk.

关键词： X-rays binaries-accretion-accretion disks-X-rays individual (Swift J1728.9-3613)

Robust Optimal Framework for Doubly Fed Induction Generator with Uncertain Dynamics

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Protection and Control of Modern Power Systems 2024年第5期9卷 129-141页

作者： Yongfeng Lü Xiaowei Zhao Priyank Shah College of Electrical and Power Engineering Taiyuan University of TechnologyTaiyuan 030024China Intelligent Control and Smart energy(ICSE)Research Group School of EngineeringThe University of WarwickCoventry CV47ALUK

A robust optimal framework is designed herein to mitigate the oscillatory dynamics in a doubly fed induction generator(DFIG)even in the presence of network disturbances and input *** address uncertain dynamics,herein,a novel transformation formula is developed for a wind energy conversion *** unscented Kalman filter is applied to estimate the un-measured internal states of the wind energy conversion system using terminal *** detailed convergence and stability analyses of the presented framework are investigated to validate its ***,comparative modal analyses are carried out to demonstrate the improvement in the damping of critical low-frequency oscillatory modes using the presented *** simulation results demonstrate satisfactory performance under various operating scenarios,such as increasing and decreasing wind speed and varying the terminal *** comparative performance is demonstrated to validate the effectiveness of the presented framework over that of the state-of-the-art *** Terms—Optimal control,power system,renew-able energy sources,wind energy conversion system,doubly fed induction generator.

关键词： Optimal control power system renew-able energy sources wind energy conversion system doubly fed induction generator

Comparing four machine learning algorithms for household non-intrusive load monitoring

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energy and AI 2024年第3期17卷 206-219页

作者： Thomas Lee Young James Gopsill Maria Valero Sindre Eikevåg Ben Hicks University of Bristol UK

The combination of Machine Learning (ML), smart energy meters, and availability of household appliance energy profile data has opened new opportunities for Non-Intrusive Load Monitoring (NILM). However, the number of options makes it challenging in selecting optimal combinations for different energy applications, which requires studies to examine their *** paper contributes one such study that investigated four established ML approaches – K Nearest Neighbour (KNN), Support Vector Machine (SVM), eXtreme Gradient Boosting (XGBoost) and Convolutional Neural Network (CNN) – and their performance in classifying appliance events from Alternating Current (AC) and Root Mean Square (RMS) energy data where the sampling frequency and training dataset set size was varied (10 Hz–1 kHz and 50–2000 examples per class, respectively). The computational expense during training, testing and storage was also assessed and evaluated with reference to real-world *** CNN classifier trained on AC data at 500 Hz and 11,000 examples gave the best F1-score (0.989) followed by the KNN classifier (0.940). The storage size required by the CNN models was 3̃MB, which is very close to fitting on cost-effective embedded system microcontrollers. This would prevent high-rate data needing to be sent to the cloud as analysis could be performed on edge computing Internet-of-Things (IoT) devices.

关键词： NILM ML Edge computing Signal processing Smart meters

Fluid-rock interaction experiments with andesite at 100℃ for potential carbon storage in geothermal reservoirs

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Deep Underground Science and Engineering 2024年第3期3卷 369-382页

作者： Grace E.Belshaw Elisabeth Steer Yukun Ji Herwin Azis Benyamin Sapiie Bagus Muljadi Veerle Vandeginste School of Chemistry University of NottinghamNottinghamUK Geoenergy Research Centre University of NottinghamNottinghamUK British Geological Survey KeyworthUK State Key Laboratory of Intelligent Construction and Healthy Operation and Maintenance of Deep Underground Engineering China University of Mining and TechnologyXuzhouChina PT Supreme energy JakartaIndonesia Faculty of Earth Sciences and Technology Institut Teknologi BandungBandungIndonesia Faculty of Engineering University of NottinghamNottinghamUK Department of Materials Engineering KU LeuvenCampus BrugesBrugesBelgium

Geothermal energy extraction often results in the release of naturally occurring carbon dioxide(CO_(2))as a *** on carbon storage using volcanic rock types other than basalt under both acidic and elevated temperature conditions has been limited so *** study uses batch reactor experiments at 100℃ to investigate the dissolution of andesite rock samples obtained from an active geothermal reservoir in Sumatra(Indonesia).The samples are subjected to reactions with neutral-pH fluids and acidic fluids,mimicking the geochemical responses upon reinjection of geothermal fluids,either without or with dissolved acidic gases,*** elemental analysis reveals the release of Ca^(2+)ions into the fluids through the dissolution of *** overall dissolution rate of the rock samples is 2.4×10^(–11)to 4.2×10^(–11)mol/(m^(2)·s),based on the Si release during the initial 7 h of the *** dissolution rates are about two orders of magnitude lower than those reported for basaltic rocks under similar reaction *** study offers valuable insights into the potential utilization of andesite reservoirs for effective CO_(2) storage via mineralization.

关键词： andesite carbon sequestration geothermal reservoirs plagioclase dissolution

Effect of Aging on the Toughness of Austenitic and Duplex Stainless Steel Weldments

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Journal of Materials Science & Technology 2010年第9期26卷 810-816页

作者： Omyma Hassan Ibrahim Ibrahim Soliman Ibrahim Tarek Ahmed Fouad Khalifa Metallurgy Dept. Nuclear Research CentreAtomic Energy Authority(Egypt) Nuclear Safety Centre Atomic Energy Authority(Egypt) Shoubra Faculty of Engineering Benha University

In the present study,the effect of aging heat treatment at 650,750,and 850？C on the impact toughness of 316L austenitic stainless steel,2205 duplex stainless steel and their weldments has been *** process was conducted using the TIG（tungsten inert gas） welding *** impact testing,at room temperature,was employed to determine the effect of aging treatment on the impact properties of investigated *** treatment resulted in degradation in the impact toughness as demonstrated by the reduction in the impact fracture energy and deformation parameters（strain hardening capacity,fracture deffection,and crack initiation and propagation energy）.The degree of embrittlement was more noticeable in duplex stainless steel parent and weld-metal than in 316L stainless steel and became greater with the increase of aging *** degradation in impact toughness was discussed in relation to the observed precipitation of the intermetallic sigma phase in the microstructure of the stainless steel weldments and the corresponding fracture surface morphology.

关键词： Austenitic and duplex stainless steels Aging Instrumented impact Toughness

Performance of the Aluminide Coating of SomeLow Alloy Steels

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Journal of Materials Science & Technology 1997年第6期13卷 462-466页

作者： H.M.Soliman and M.E.Abd E1-Azim(Metallurgy Dept., atomic energy authority, Cairo, Egypt ) Metallurgy Dept. Atomic Energy Authority Cairo Egypt

Two low alloy steels 0.5Cr-0.5Mo-0.25V and H85 were pack-aluminized at 900°for 4 h by using Fe-Al powder mixture containing 48% Fe, 20.6% Al- 29.4% Al2O3 and 2% NH4Cl by weight. The microhardness and oxidation resistance at 900℃ of the aluminide coatings were studied. It was found that pack-aluminizing improves the microhardness of the 0.5Cro.5Mo-0.25V steel while it reduces the microhardness of the H85 steel. Pack aluminizing highly improves the oxidation resistance after 20h exposure at 900℃ in air for the investigated steels.

关键词： Cr Performance of the Aluminide Coating of SomeLow Alloy Steels

Comparison of Impact Properties for Carbon and Low Alloy Steels

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Journal of Materials Science & Technology 2011年第10期27卷 931-936页

作者： O.H.Ibrahim Metallurgy Dept. Nuclear Research CentreAtomic Energy Authority

The impact properties of hot rolled carbon steel （used for the manufacture of reinforcement steel bars） and the quenched ＆ tempered （Q＆T） low alloy steel （used in the pressure vessel industry） were determined. The microstructure of the hot rolled carbon steel contained ferrite/pearlite phases, while that of the quenched and tempered low alloy steel contained bainite structure. Impact properties were determined for both steels by instrumented impact testing at temperatures between -150 and 200℃. The impact properties comprised total impact energy, ductile to brittle transition temperature, crack initiation and propagation energy, brittleness transition temperature and cleavage fracture stress. The Q＆T low alloy steel displayed much higher resistance to ductile fracture at high test temperatures, while its resistance to brittle fracture at low test temperatures was a little higher than that of the hot rolled carbon steel. The results were discussed in relation to the difference in the chemical composition and microstructure for the two steels.

关键词： Ferritic/pearlitic steel Bainitic steel Impact properties

Analytical and simulation studies for diode and triode ion beam extraction systems

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Chinese Physics C 2012年第4期36卷 344-349页

作者： M. M. Abdelrahman N. I. Basal S. G. Zakhary Accelerators & Ion Sources Department Nuclear Research Center Atomic Energy Authority P.O. Box: 13759 Inchas Atomic Energy Authority

This work is concerned with ion beam dynamics and compares the emittance to aberration ratios of two-and three-electrode extraction systems. The study is conducted with the aid of Version 7 of SIMION 3D ray-tracing software. The beam dependence on various parameters of the extraction systems is studied and the numerical results lead to qualitative conclusions. Ion beam characteristics using diode and triode extraction systems are investigated with the aid of the computer code SIMION 3 D, Version 7.0. The diode （two electrode extraction system） and triode （three- electrode extraction, acceleration-deceleration system） extraction systems are designed and optimized with different geometric parameters of the electrode system, voltage applied to the extraction electrode, and plasma parameters inside the ion source chamber, as well as by the ion beam space charge. This work attempts to describe the importance of the acceleration-deceleration extraction system. It shows that besides an increase of the beam energy, the ion beam has lower emittance than the two-electrode extraction system. Ion beams of the highest quality are extracted whenever the half-angular divergence is minimum for which the perveance current intensity and the extraction gap have optimum value. Knowing the electron temperature of the plasma is necessary to determine plasma potential and the exact beam energy.

关键词： ion beam emittance plasma meniscus space charge ion beam SIMION computer program

Localized Corrosion Behavior of 6% Mo Super Austenitic & 316L Stainless Steels in Low pH 3% NaCl Solution

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Journal of Materials Science & Technology 2005年第4期21卷 465-469页

作者： M.M.A.Gad H.G.Salem A.M.Nasreldin H.Sabry A.A.EI-Sayed Metallurgy Department Atomic Energy Authority Cairo EgyptMechanical Engineering Department AUC Cairo EgyptMetallurgy Department Atomic Energy Authority Cairo EgyptEuropean Neighbourhood and Partnership Instrument (ENPI) Cairo EgyptMetallurgy Department Atomic Energy Authority Cairo Egypt

Electrochemical techniques were applied to study the crevice corrosion resistance of two types of stainless steel alloys namely, conventional 316L and 6% Mo super austenitic in acidified 3% NaCl solution at room *** results showed that 6% Mo alloy possessed a remarkable resistance to crevice corrosion compared with 316L alloy when they are tested in the same solution. The breakdown potential at which passivity broke down for 316L alloy was 0.00 mV （SCE）. The corresponding value for 6% Mo alloy could not reach up to the potential value of 700 mV （SCE）. 316L alloy suffered extremely from crevice corrosion at room temperature （about 25℃）, which indicates that the critical crevice corrosion temperature, below which crevice corrosion does not occur, was lower than the test temperature. For 6% Mo alloy, the critical crevice corrosion temperature was higher than the testing temperature. Electrochemical parameters indicated that 6% Mo alloy exhibited higher crevice corrosion resistance than 316L alloy.

关键词： Crevice corrosion 6% Mo super austenitic Conventional 316L Critical crevice temperature