In situ XRD reaction device combined with the online gas chromatography was used to study the oxidation behavior of the effect of H 2 O content (4.36%, 1.68%, 0.56%) on the phase and Fischer-Tropsch synthesis (FTS) pe...
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In situ XRD reaction device combined with the online gas chromatography was used to study the oxidation behavior of the effect of H 2 O content (4.36%, 1.68%, 0.56%) on the phase and Fischer-Tropsch synthesis (FTS) performance of the single phase Fe 5 c 2 . The results show that the oxidation rate of the Fe 5 c 2 phase increases with the increase of the content of injected H 2 O. Meanwhile, the particle size of Fe 5 c 2 phase decreases and more active sites exposes during the H 2 O oxidation, resulting in the increase of the FTS activity. Furthermore, the FTS activity increases with the increase of the oxidation times, but the selectivity of cH 4 increases and the c 5+ selectivity decreases gradually.
Vapor recompression (VRc) based heat integration is usually employed for purifying a propylene-propane mixture in a c 3 splitter. A fixed speed drive or a variable speed drive compressor may be employed for overhead v...
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Vapor recompression (VRc) based heat integration is usually employed for purifying a propylene-propane mixture in a c 3 splitter. A fixed speed drive or a variable speed drive compressor may be employed for overhead vapor recompression. In this work, economiccontrollable designs for the two compressor types in a VRcc 3 splitter are obtained via rigorous steady state and pressure driven closed loop dynamic simulations. A simple dual ended decentralized composition control system is shown to provide effective column regulation. The economiccontrollable design results indicate that when a fixed speed drive compressor is used, significant pressure drop must be provided across the compressor suction throttling valve for sufficient rangeability towards worst-case disturbance rejection. Accordingly, the column pressure and necessary compression ratio are higher for an overall more expensive process compared to a variable speed drive compressor. The case study highlights the importance for considering control at the conceptual design stage for designing a robust operable process.
D-Gun thermal spray technique was used to deposit cr 3 c 2 -Nicr and cr 2 O 3 coatings on T-11 boiler steel in the present study. Hot corrosion behavior of coated and uncoated samples of T-11 boiler was analyzed for 5...
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D-Gun thermal spray technique was used to deposit cr 3 c 2 -Nicr and cr 2 O 3 coatings on T-11 boiler steel in the present study. Hot corrosion behavior of coated and uncoated samples of T-11 boiler was analyzed for 50 cycles at 900 °c in the simulated Na 2 SO 4 -60%V 2 O 5 condition. Kinetics of corrosion was measured by using thermogravimetric studies. Surface and cross sectional analysis has been reported by using XRD and SEM/EDS to know the formation of corrosion products. Uncoated sample has shown spalling and degradation of oxide scale. cr 2 O 3 coated sample has shown detachment of coating from the substrate after 1st cycle. cr 3 c 2 -Nicr coating has shown the protective behavior as well as corrosion resistance in the reported environment by virtue of protective oxides.
Remanufacturing is an advanced stage in the development of maintenance engineering and surface engineering, which is an important component of sustainable manufacturing. As a significant remanufacturing technology, th...
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Remanufacturing is an advanced stage in the development of maintenance engineering and surface engineering, which is an important component of sustainable manufacturing. As a significant remanufacturing technology, thermal spraying is an important basis for the development of surface engineering. In this paper, cr 3 c 2 -Nicr coatings with different porosity were prepared by plasma spraying, and their wear behaviour under oil lubrication was studied. The results show that the wear mechanisms of the coatings are different with difference of the porosity. Abrasive wear is the main wear mechanism of the high-porosity coating, while adhesive wear is the main wear mechanism of the low-porosity coating.
In hot metal forming, the tool (die) is subjected to complex tribological problems during its interaction with the workpiece and needs more understanding. The reduction in the lifetime of hot forming die by surface de...
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In hot metal forming, the tool (die) is subjected to complex tribological problems during its interaction with the workpiece and needs more understanding. The reduction in the lifetime of hot forming die by surface degradation is observed as a major problem and adversely affects the process economy. One of the foremost methods of combating wear is the development of wear-resistant surface coatings. However, the study of basic friction behaviour and wear mechanism by which the coatings wear needs more attention. In the current research, the potential of atmospheric plasma-sprayed cr 3 c 2 -Nicr coating on hot forming steel as the wear-resistance coating was explored. The coating was developed on widely used hot forming tool steel namely AISI H13. The microstructure of the coating was found to be dense and uniform with a bond strength of 63.94 ± 4 MPa. The coating hardness and porosity was found to be 830 ± 38 HV and 1.7 ± 0.5% respectively. The friction and wear tests were conducted on a pin-on-disc high-temperature tribometer under two load conditions (25 N and 50 N) and at three temperatures (Room temperature, 400 °c and 800 °c). The specific wear rate was found lower at all testing conditions for the coated surface than uncoated counterparts. The lowest value of specific wear rate and coefficient of friction in the coated specimen was found at the test conducted at 50 N load and temperature of 400 °c. The wear mechanism of worn-out specimens was analyzed using scanning electron microscopy (SEM). The wear mechanism was found more adhesive at room temperature and a combination of adhesive and abrasive at elevated temperature.
This article presents the design and evaluation of a robust c ⁎ control law through Hardware-In-the-Loop Simulation (HILS) of JAXA’s research aircraft called Multi-Purpose Aviation Laboratory (MuPAL-α). The c ⁎ cont...
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This article presents the design and evaluation of a robust c ⁎ control law through Hardware-In-the-Loop Simulation (HILS) of JAXA’s research aircraft called Multi-Purpose Aviation Laboratory (MuPAL-α). The c ⁎ control law, which is a widely used flight control architecture in aviation industries, is designed using structured H ∞ synthesis. This design method provides robustness of the controller for flight condition changes and uncertainties associated with the dynamics of MuPAL-α. HILS tests allow on-ground evaluation of controllers using actual actuators. The HILS results show that the designed controller adequately tracks pilot commands in the presence of airspeed variation, uncertainties in the modeling of the onboard actuators, and wind gust.
In the present work the combined effects of particle size and distribution on the mechanical properties of the 20vol.% B 4 c particle reinforced Al–cu alloy composites by powder metallurgy is investigated. The aim of...
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In the present work the combined effects of particle size and distribution on the mechanical properties of the 20vol.% B 4 c particle reinforced Al–cu alloy composites by powder metallurgy is investigated. The aim of this work was to evaluate the effect of mixing time (5h, 15h and 25h) and particle size (23µm and 67µm) of B 4 c particles on the metallurgical and mechanical properties. It has been found that small ratio between matrix/reinforcement particles sizes resulted in more uniform distribution in the matrix. The particles distributed more uniformly in the matrix with increasing in mixing time. The results also showed that homogenous distribution of the B 4 c particles resulted in higher hardness, ultimate tensile strength, yield strength and elongation. Fracture surface observations showed that the dominant fracture mechanism of the composites with small B 4 c particle size (23µm) is ductile fracture of the matrix, accompanied by the “pull-out” of the particles from the matrix, which is attributed to positive effect of reinforcement particles in resistance to the movement of dislocations while the dominant fracture mechanism of the composites with large B 4 c particle size (67µm) is ductile fracture of the matrix, accompanied by the B 4 c particle fracture
A rat model of chronic tympanic membrane perforation was developed to be used in the search of new materials for the sealing of these perforations. A longitudinal study was carried out in rats subjected to incisional ...
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A rat model of chronic tympanic membrane perforation was developed to be used in the search of new materials for the sealing of these perforations. A longitudinal study was carried out in rats subjected to incisional myr-ingotomy followed by the application of mitomycin c alone or with dexamethasone. Rats were checked at days 3, 7,1 0,1 4 and weekly thereafter until perforation closure, for up to 6 months. The addition of dexamethasone is a key component in order to obtain a chronic opening. Myringotomies treated w ith saline had a mean healing time of 8.5 days. At 8 weeks, between 62.5% and 77.7% of tympanic membranes treated w ith mitomycin c and dexamethasone remained perforated and at 6 months this number fell to 21.4%. This technique is able to maintain most tympanic membrane perforations patent for at least 8 weeks. This rat model is adequate for its use in preclinical or translational research.
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