Magnetically induced phase separation in the fcc phase and thermodynamic calculations of phase equilibria of the Co-Cr system

Two-phase equilibria between the ferromagnetic fcc and the paramagnetic fcc phase from 800 ℃ to 900 ℃ in the Co-rich region have been detected by the diffusion couple technique. Two phase separation region of the fcc has been confirmed along the Curie temperature.The phase equilibria including the present results and the thermodynamic data of the Co-Cr system reported in the literature were analyzed on the basis of the thermodynamic evaluation. A set of thermodynamic values for the liquid, fcc, hcp, bcc, sigma phases was obtained. The calculated phase equilibria were in good agreement with most of the experimental data.

FCC riser quick separation system: a review

The riser reactor is the key unit in the fluid catalytic cracking（FCC） process. As the FCC feedstocks become heavier, the product mixture of oil, gas and catalysts must be separated immediately at the outlet of the riser to avoid excessive coking. The quick separation system is the core equipment in the FCC unit. China University of Petroleum（Beijing） has developed many kinds of separation system including the fender-stripping cyclone and circulating-stripping cyclone systems, which can increase the separation efficiency and reduce the pressure drop remarkably. For the inner riser system, a vortex quick separation system has been developed. It contains a vortex quick separator and an isolated shell. In order to reduce the separation time, a new type of separator called the short residence time separator system was developed. It can further reduce the separation time to less than 1 s. In this paper, the corresponding design principles,structure and industrial application of these different kinds of separation systems are reviewed. A system that can simultaneously realize quick oil gas separation, quick oil gas extraction and quick pre-stripping of catalysts at the end of the riser is the trend in the future.

Metallurgical analysis of a failed maraging steel shear screw used in the band separation system of a satellite launch vehicle

Maraging steels have excellent combination of strength and toughness and are extensively used for a variety of aerospace applications. In one such critical application, this steel was used to fabricate shear screws of a stage separation system in a satellite launch vehicle. During assembly preparations, one of the shear screws which connected the separation band and band end block has failed at the first thread. Microstructural analysis revealed that the crack originated from the root of the thread and propagated in an intergranular mode. The failure is attributed to combined effect of stress and corrosion leading to stress corrosion cracking.

Analytical solution for the time-fractional heat conduction equation in spherical coordinate system by the method of variable separation

In this paper,using the fractional Fourier law,we obtain the fractional heat conduction equation with a time-fractional derivative in the spherical coordinate system.The method of variable separation is used to solve the timefractional heat conduction equation.The Caputo fractional derivative of the order 0 〈 α≤ 1 is used.The solution is presented in terms of the Mittag-Leffler functions.Numerical results are illustrated graphically for various values of fractional derivative.

First-principles calculation of phase equilibria and phase separation of the Fe-Ni alloy system

Theoretical investigation of the phase equilibria of the Fe-Ni alloy has been performed by combining the FLAPW total energy calculations and the Cluster Variation Method through the Cluster Expansion Method. The calculations have proved the stabilization of the LIE phase at 1：3 stoichiometry, which is in agreement with the experimental result, and predicted the existence of L1 0 as a stable phase below 550 K; this L1 0 phase has been missing in the conventional phase diagram. The calculations are extended to the Fe-rich region that is characterized by a wide range phase separation and has drawn considerable attention because of the intriguing Invar property associated with a Fe concentration of 65%. To reveal the origin of the phase separation, a P-V curve in an entire concentration range is derived by the second derivative of free energy functional of the disordered phase with respect to the volume. The calculation confirmed that the phase separation is caused by the breakdown of the mechanical-stability criterion. The newly calculated phase separation line combined with the L1 0 and L12Eorder-disordered phase boundaries provides phase equilibria in the wider concentration range of the system. Furthermore, a coefficient of thermal expansion （CTE） is attempted by incorporating the thermal vibration effect through harmonic approximation of the Debye-Gruneisen model. The Invar behavior has been reproduced, and the origin of this anomalous volume change has been discussed.

Separation of Neighboring REElementsfrom Sm_2O_3Eu_2O_3Gd_2O_3 System by a Stepwise ChlorinationChemical Vapor Transport Reaction

The mutual separation characteristics were investigated for the neighboring Sm, Eu and Gd from their ternary oxide mixture Sm 2O 3 Eu 2O 3 Gd 2O 3 by a stepwise chlorination chemical vapor transport reaction within 6 h using AlCl 3 as complex former. The rare earth chlorides were more readily transported and concentrated in the middle temperature range of 980～1100 K and the transport efficiency was in the order of Sm≈Gd>Eu. The separation factor, expressed as molar ratio for the resulting chlorides, was 1 70 for Eu∶Sm, 1 88 for Eu∶Gd, 1 24 for Sm∶Gd in the higher temperature region, and 2 76 for Sm∶Eu, 2 83 for Gd∶Eu and 1 12 for Gd∶Sm in the lower temperature region, respectively. All results are much higher than those of the conventional wet process.

Flat Belt Separation System under Slat in Fattening Pig Housing: Effect of Belt Slope Angle

In this study, the separation and drying efficiency of the excreta, separated into solid and liquid fraction by a flat conveyor belt under a partial slatted floor in a facility for fattening pigs, was determined. Two transverse slope angles (4&#176 and 6&#176) for the flat belts were used, in a trial with pigs from 20.61 to 117.83 kg of live weight (LW), and the sample size was 7 pigs per pen, 42 pigs per room. The flat belt was more efficient with 6° than with 4° slope angle (32.65% vs. 29.91% dry matter content of solid fraction during the whole fattening period, respectively;P &#176 than for the 4&#176 (1.4137 vs. 1.3030, during the whole fattening period;P &#176, this efficiency was not improved in finishing period -83.40 to 117.83 kg LW (two extractions per day) with regard to the growth period -20.61 to 83.40 kg LW (one extraction per day). Meanwhile, with 4&#176 it did improved. The ventilation system underneath slat seems to play a key role in the obtained results.

A FUZZY MATCH BASED EXPERT SYSTEM FOR SYNTHESIS OF SEPARATION PROCESSES

A predictive parallel search algorithm,the fuzzy match inference strategy,is implemented ina prototype expert system.Selection of separation technologies and sequencing of separators are beingapproached in an integrated manner.The fuzzy match mechanism results in a relatively smaller subsetof favored schemes,constituting a hyperstructure for further quantitative evaluation and combinationoptimization.An industrial application example of aromatics extraction separation is presented.

Type selection and maintenance of the control system of large-scale air separation units

Based on the practice of Baosteel＇ s 60000 m3/h air separation unit （ASU） ,which is the first domestically- integrated unit of such a scale, this paper studies the principles of type selection of the distribution control system （DCS）. It discusses the design of the unit＇s control system,which involves a compressor system,a purification system （molecular sieving）, a turbo expansion system and an air separation system. The final part of the paper discusses the maintenance and future development of the ASU control system at Baosteel.

Variable separation solutions and new solitary wave structures to the （l＋l）-dimensional Ito system

A variable separation approach is proposed and extended to the （1＋1）-dimensional physics system. The variable separation solution of （1-F1）-dimensional Ito system is obtained. Some special types of solutions such as non-propagating solitary wave solution, propagating solitary wave solution and looped soliton solution are found by selecting the arbitrary function appropriately.

Microfluidic Analytical System with On-Line Luminol Chemiluminescence Detection Based on Annular Flow of Phase Separation Multiphase Flow

Microfluidic analytical system was developed based on annular flow of phase separation multiphase flow with a ternary water-hydrophilic/hydrophobic organic solvent solution. The analytical system was combined with on-line luminol chemiluminescence detection for catechin analysis. The water (10 mM phosphate buffer, pH 7.3)-acetonitrile-ethyl acetate mixed solution (3:8:4, volume ratio) containing 60 μM luminol and 2 mM hydrogen peroxide as a carrier was fed into the capillary tube (open-tubular fused-silica, 75 μm inner diameter, 110 cm effective length) at a flow rate of 1.0 μL·min-1. The carrier solution showed stable chemiluminescence as a baseline on the flow chart. Eight catechins were detected as negative peaks for their antioxidant potential with different detection times. The system was applied to analyze the amounts of catechin in commercially available green tea beverages.

ls-Ponomarev-systems与1-序列覆盖映像

为了寻求局部可分度量空间的映像,引入双点星sn覆盖这一概念,并借用近年来由传统的Ponomarev-system推广而得的ls-Ponomarev-system,给出了局部可分度量空间1-序列覆盖映像的一个新刻画,并且这一新刻画较以往所得相关刻画更为简洁.

Recent advances on the membrane processes for CO_2 separation

Membrane separation technology has popularized rapidly and attracts much interest in gas industry as a promising sort of newly chemical separation unit operation. In this paper, recent advances on membrane processes for CO_2 separation are reviewed. The researches indicate that the optimization of operating process designs could improve the separation performance, reduce the energy consumption and decrease the cost of membrane separation systems. With the improvement of membrane materials recently,membrane processes are beginning to be competitive enough for CO_2 separation, especially for postcombustion CO_2 capture, biogas upgrading and natural gas carbon dioxide removal, compared with the traditional separation methods. We summarize the needs and most promising research directions for membrane processes for CO_2 separation in current and future membrane applications. As the time goes by, novel membrane materials developed according to the requirement proposed by process optimization with increased selectivity and/or permeance will accelerate the industrialization of membrane process in the near future. Based on the data collected in a pilot scale test, more effort could be made on the optimization of membrane separation processes. This work would open up a new horizon for CO_2 separation/Capture on Carbon Capture Utilization and Storage(CCUS).

Particle size distribution of coal and gangue after impact-crush separation

Based on the separation and backfilling system of coal and gangue, the mineral material impact experiments were conducted utilizing the hardness difference between coal and gangue according to the uniaxial compression experiments. The broken coal and gangue particles were collected and screened by different size meshes. The particle size distributions of coal and gangue under different impact velocities were researched according to the Rosin-Rammler distribution. The relationships between separation indicators and impact velocities were discussed. It is found from experiments that there is a fully broken boundary of coal material. The experimental results indicate that the Rosin-Rammler distribution could accurately describe the particle size distribution of broken coal and gangue under different impact velocities, and there is a minimum overlap region when the impact velocity is 12.10 m/s which leads to the minimum mixed degree of coal and gangue, and consequently the benefit of coal and gangue separation.

Thermodynamic analysis of separating lead and antimony in chloride system

In chloride system, thermodynamic analysis is a useful guide to separate lead and antimony as well as to understand the separation mechanism. An efficient and feasible way for separating lead and antimony was discussed. The relationships of [Pb2+][Cl-]2—lg[Cl]T and E—lg[Cl]T in Pb-Sb-Cl-H2O system were studied, and the solubilities of lead chloride at different antimony concentrations were calculated based on principle of simultaneous equilibrium. The results show that insoluble salt PbCl2 will only exist stably in a certain concentration range of chlorine ion. This concentration range of chlorine ion expands a little with increasing the concentration of antimony in the system while narrows as the system acidity increases. The solubility of Pb2+ in solution decreases with increasing the concentration of antimony in the system, whereas increases with increasing the concentration of total chlorine. The concentration range of total chlorine causing lead solubility less than 0.005 mol/L increases monotonically.

Ejection Separation Characteristic Analysis of Parachute Container Cover from Return Capsule for Lunar Exploration

The parachute container cover ejection separation is the first and foremost motion for the return capsule recovery system,which is related to the success of a recovery system.Adopting the computational fluid dynamics(CFD)simulation and flight dynamics coupling method,the parachute container cover ejection separation is simulated.The rationality of the ejection separation speed and dynamic characteristics of the separation process is analyzed.Meanwhile,the influences of angle of attack,Mach number and ejection separation speed on the parachute container cover ejection are also investigated.Results show that the ejection separation speed design is reasonable.It has a certain design margin for parachute container cover to escape from the wake region,and to pull out the drag parachute completely.The results may provide a theoretical basis for recovery system engineering design of the lunar exploration project.

Simple and universal method in designs of high-efficiency diffractive optical elements for spectrum separation and beam concentration

Diffractive optical elements（DOEs） with spectrum separation and beam concentration（SSBC） functions have important applications in solar cell systems. With the SSBC DOEs, the sunlight radiation is divided into several wave bands so as to be effectively absorbed by photovoltaic materials with different band gaps. A new method is proposed for designing high-efficiency SSBC DOEs, which is physically simple, numerically fast, and universally applicable. The SSBC DOEs are designed by the new design method, and their performances are analyzed by the Fresnel diffraction integral method.The new design method takes two advantages over the previous design method. Firstly, the optical focusing efficiency is heightened by up to 10%. Secondly, focal positions of all the designed wavelengths can be designated arbitrarily and independently. It is believed that the designed SSBC DOEs should have practical applications to solar cell systems.

Model-based Predictive Control for Spatially-distributed Systems Using Dimensional Reduction Models

In this paper, a low-dimensional multiple-input and multiple-output （MIMO） model predictive control （MPC） configuration is presented for partial differential equation （PDE） unknown spatially-distributed systems （SDSs）. First, the dimension reduction with principal component analysis （PCA） is used to transform the high-dimensional spatio-temporal data into a low-dimensional time domain. The MPC strategy is proposed based on the online correction low-dimensional models, where the state of the system at a previous time is used to correct the output of low-dimensional models. Sufficient conditions for closed-loop stability are presented and proven. Simulations demonstrate the accuracy and efficiency of the proposed methodologies.

Observer-based H-infinity control in multiple channel networked control systems with random packet dropouts

This paper investigates the observer-based H-infinity control problem for networked control systems （NCSs） with random packet dropouts. A general packet dropout model with multiple independent stochastic variables in the multiple channels case is adopted to describe the data missing in the limited communication channels. With the consideration of the sensor-to-controller and controller-to-actuator packet dropouts at the same time, a new method is pro- posed based on a separation lemma to design an observer-based H-infinity controller, which exponentially stabilizes the closed-loop system in the sense of mean square and also achieves a prescribed H-infinity disturbance attenuation level. A numerical example is given to illustrate the effectiveness of the proposed control method.

Study on Electromagnetic Transient Condition of EMU Passing by Phase-separation with Electric Load in High-speed Railway

Aiming at the complex electromagnetic transient process of EMU passing by phase-separation with electric load in high-speed railway, mechanism of overvoltage caused by switching off, overvoltage caused by switching on and impact current is analyzed systematically in this article. π-type equivalent circuit of feeding section is put forward in the analysis of overvoltage mechanism. Overvoltage and overcurrent model of passing by phase-separation with electric load are also built. Correctness of mechanism was validated by simulation. In addition, the methods to solve the influence on substations, transformers and protection devices in this process are put forward, which provides a new idea on passing by phase-separation with electric load technology.