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991.
Boiler tube steels, namely low carbon steel ASTM-SA-210-Grades A1 (GrA1), 1Cr-0.5Mo steel ASTM-SA213-T-11 (T11), and 2.25Cr-1
Mo steel ASTM-SA213-T-22(T22), were used as substrate steels. Ni-22Cr-10Al-1Y powder was sprayed as a bond coat 150 μm thick
before a 200 μm final coating of Ni-20Cr was applied Coatings were characterized prior to testing in the environment of a
coal fire boiler. The uncoated and coated steels were inserted in the platen superheater zone of a coal fired boiler at around
755°C for 10 cycles, each 100 h. Coated steels showed lower degradation (erosion-corrosion) rate than uncoated steels showed.
The lowest rate was observed in the case of Ni-20Cr coated T11 steel. Among the uncoated steels, the observed rate of degradation
was the lowest for the T22 steel. 相似文献
992.
U. S. Dixit S. Chandra 《The International Journal of Advanced Manufacturing Technology》2003,22(11-12):883-889
Neural network models can be effectively used to predict any type of functional relationship. In this paper, a neural network model is used to predict roll force and roll torque in a cold flat rolling process, as a function of various process parameters. A strategy is developed to obtain a prescribed accuracy of prediction with a minimum number of data for training and testing. The effect of increasing the size of training and testing data set is also examined. After the prediction of most likely value, upper and lower bound estimates are also found with the help of the neural network. With these estimates, the predicted value can be represented as a fuzzy number for use in fuzzy-logic based systems. 相似文献
993.
Cr3C2-NiCr, NiCr, WC-Co and Stellite-6 alloy coatings were sprayed on ASTM SA213-T11 steel using the HVOF process. Liquid petroleum
gas was used as the fuel gas. Hot corrosion studies were conducted on the uncoated as well as HVOF sprayed specimens after
exposure to molten salt at 900 °C under cyclic conditions. The thermo-gravimetric technique was used to establish the kinetics
of corrosion. XRD, SEM/EDAX and EPMA techniques were used to analyze the corrosion products. All these overlay coatings showed
a better resistance to hot corrosion as compared to that of uncoated steel. NiCr Coating was found to be most protective followed
by the Cr3C2-NiCr coating. WC-Co coating was least effective to protect the substrate steel. It is concluded that the formation of Cr2O3, NiO, NiCr2O4, and CoO in the coatings may contribute to the development of a better hot-corrosion resistance. The uncoated steel suffered
corrosion in the form of intense spalling and peeling of the scale, which may be due to the formation of unprotective Fe2O3 oxide scale. 相似文献
994.
Effect of substrate temperature on adhesion strength of plasma-sprayed nickel coatings 总被引:1,自引:0,他引:1
V. Pershin M. Lufitha S. Chandra J. Mostaghimi 《Journal of Thermal Spray Technology》2003,12(3):370-376
We plasma-sprayed nickel coatings on stainless steel and cobalt alloy coupons heated to temperatures ranging from room temperature
to 650 °C. Temperatures, velocities, and sizes of spray particles were recorded while in-flight and held constant during experiments.
We measured coating adhesion strength and porosity, photographed coating microstructure, and determined thickness and composition
of surface oxide layers on heated substrates. Coating adhesion strength on stainless steel coupons increased from 10–74 MPa
when substrate temperatures were raised from 25–650 °C. Coating porosity was lower on high-temperature surfaces. Surface oxide
layers grew thicker when substrates were heated, but oxidation alone could not account for the increase in coating adhesion
strength. When a coupon was heated to 650 °C and allowed to cool before plasma-spraying, its coating adhesion strength was
much less than that of a coating deposited on a surface maintained at 650 °C. Cobalt alloy coupons, which oxidize much less
than stainless steel when heated, also showed improved coating adhesion when heated. Heating the substrate removes surface
moisture and other volatile contaminants, delays solidification of droplets so that they can better penetrate surface cavities,
and promotes diffusion between the coating and substrate. All of these mechanisms enhance coating adhesion. 相似文献
995.
996.
997.
Ashok Chhetry Sudeep Sharma Sharat Chandra Barman Hyosang Yoon Seokgyu Ko Chani Park Sanghyuk Yoon Hyunsik Kim Jae Yeong Park 《Advanced functional materials》2021,31(10):2007661
Smart electronic skin (e-skin) requires the easy incorporation of multifunctional sensors capable of mimicking skin-like perception in response to external stimuli. However, efficient and reliable measurement of multiple parameters in a single functional device is limited by the sensor layout and choice of functional materials. The outstanding electrical properties of black phosphorus and laser-engraved graphene (BP@LEG) demonstrates a new paradigm for a highly sensitive dual-modal temperature and strain sensor platform to modulate e-skin sensing functionality. Moreover, the unique hybridized sensor design enables efficient and accurate determination of each parameter without interfering with each other. The cationic polymer passivated BP@LEG composite material on polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene (SEBS) substrate outperforms as a positive temperature coefficient material, exhibiting a high thermal index of 8106 K (25–50 ° C) with high strain sensitivity (i.e., gauge factor, GF) of up to 2765 ( > 19.2%), ultralow strain resolution of 0.023%, and longer durability ( > 18 400 cycles), satisfying the e-skin requirements. Looking forward, this technique provides unique opportunities for broader applications, such as e-skin, robotic appendages, and health monitoring technologies. 相似文献
998.
Md Abu Zahed Sharat Chandra Barman Md. Sharifuzzaman Shipeng Zhang Hyosang Yoon Chani Park Sang Hyuk Yoon Jae Yeong Park 《Advanced functional materials》2021,31(25):2009018
Heteroatom-incorporated graphene represents a prominent family of materials utilized as active electrodes for multimodal sensing and energy storage applications. Herein, a novel polyaziridine-encapsulated phosphorene (PEP)-incorporated flexible 3D porous graphene (3DPG) electrode is developed using facile, cost-effective laser writing, and drop-casting techniques. Owing to the excellent electrochemical characteristics and surface functionality of the highly stable PEP, the fabricated PEP/3DPG is evaluated as a potential electrode for immunosensing, electrocardiogram (ECG) recording, and microsupercapacitors (MSCs). Under optimized conditions, the produced PEP/3DPG-based carcinoembryonic immunosensor exhibits linear ranges of 0.1–700 pg mL−1 and 1–100 ng mL−1 with a detection limit of 0.34 pg mL−1 and high selectivity. The finger touch-based ECG sensor demonstrates a relatively low and stable impedance at the skin-electrode interface; therefore, the signal-to-noise ratio of the ECG signal received from the fabricated sensor (13.5 dB) is comparable to that of conventional Ag/AgCl electrodes (13.9 dB). Besides, the highest areal capacitance of the prepared MSC reached a magnitude of 16.94 mF cm−2, which is six times higher than that of a non-doped 3DPG-based MSC. These results demonstrate the effectiveness of the described fabrication procedure and the high utilization potential of the encapsulated phosphorene-doped 3D graphene in multimodal applications. 相似文献
999.
1000.
Sasikumar Gurumoorthy Naresh Babu Muppalaneni Chandra Sekhar Golla Sandhya Kumari 《International Journal of Communication Systems》2020,33(13)
Electroencephalogram (EEG) is the signals that measure the electrical variances of brain using metal electrodes. We observe the EEG signals by using European Data Format (EDF) BROWSER and EEG STUDIO. By using EDF BROWSER, we can get the mean and frequency from the filtered output signal using band‐pass filter. Using EDF BROWSER, we can also perform Root Mean Square (RMS) and signal samples. Using EEG STUDIO, we can analyze the average frequency and standard deviation. Epileptic seizure prediction and detection are done by spike detection, frequency domain analysis, and nonlinear methods. EEG signal contains different artifacts like electrooculography (EOG), EKG, and electrocardiogram (ECG). ECG signals are produced by heart. EOG signals are produced by eyes. EMG signals are produced by muscle coordination. 相似文献