Experimental forward and reverse in situ combustion gasification of lignite with production of hydrogen-rich syngas

This research focused on the feasibility of applying the forward and reverse combustion approach to the in situ gasification of lignite with the production of hydrogen-rich syngas(H_(2)and CO).The so-called forward combustion gasification(FCG)and reverse combustion gasification(RCG)approach in which oxygen and steam are simultaneously fed to the simulated system of underground coal gasification(UCG)was studied.A simulated system of UCG was designed and established.The underground conditions of the coal seam and strata were simulated in the system.The combustion gasification of lignite has been carried out experimentally for almost 6.5 days.The average effective content(H_(2)+CO)of syngas during the FCG phase was 62.31%and the maximum content was 70.92%.For the RCG phase the corresponding figures are 61.33%and 67.91%.Thus,the feasibility of using RCG way for UCG has been demonstrated.The temperature profiles have been provided by using of 85 thermocouples during the model experiment,which portrayed the several nephograms of thermal data in the gasifier were of significance for the prospective gasification processes.

Research on Technological Process Control Model of Reverse Logistics in Manufacturing System

This paper has found out some important input factors of reverse logistics in manufacturing system throuth analysis and summary,and established four kinds of technological process control models of reverse logistics in manufacturing system according to different processing methods. These models embed each other that form a cubic control system of reverse logistics.

Mechanism of improving forward and reverse blocking voltages in AlGaN/GaN HEMTs by using Schottky drain

In this paper, we demonstrate that a Schottky drain can improve the forward and reverse blocking voltages （BVs） simultaneously in A1GaN/GaN high-electron mobility transistors （HEMTs）. The mechanism of improving the two BVs is investigated by analysing the leakage current components and by software simulation. The forward BV increases from 72 V to 149 V due to the good Schottky contact morphology. During the reverse bias, the buffer leakage in the Ohmic- drain HEMT increases significantly with the increase of the negative drain bias. For the Schottky-drain HEMT, the buffer leakage is suppressed effectively by the formation of the depletion region at the drain terminal. As a result, the reverse BV is enhanced from -5 V to -49 V by using a Schottky drain. Experiments and the simulation indicate that a Schottky drain is desirable for power electronic applications.

Design and Optimization of Reverse Salient Permanent Magnet Synchronous Motor Based on Controllable Leakage Flux

In this paper,a controllable leakage flux reverse salient permanent magnet synchronous motor(CLF-RSPMSM)is designed,which has the advantages of wide speed range and low irreversible demagnetization risk.Firstly,the principle of controllable leakage flux and reverse saliency effect is introduced,and the design of the rotor flux barrier is emphatically discussed.Secondly,multiple design variables are stratified by the comprehensive sensitivity method,and the main variables are screened out.Then the relationship between the main variables and the optimization goal is discussed according to the response surface diagram.Thirdly,a sequential nonlinear programming algorithm(SNP)is used to optimize the three optimization objectives comprehensively.Finally,the electromagnetic performance of the proposed motor is compared with the initial IPM motor,the mechanical strength of the proposed rotor is analyzed,and the results verify the effectiveness of the design and optimization method of the proposed motor.

Size Changes of Reverse Micelles after Extraction of Peanut Protein and Their Forward Extraction Rates

The aim of this study was to detect the size changes of reverse micelles after extraction of peanut protein and their forward extraction rates. Factors that affect the size of reverse micelles and the extraction of peanut protein were also investigated. The size of reverse micelles and the size changes were measured according to the theory of dynamic light scattering under different conditions such as different sodium bis(2-ethylhexyl) sulfosuccinate(AOT) concentrations, p H values, ion concentrations, and salt species.With the increase of AOT surfactant concentrations in a certain range, the size of empty and full reverse micelles increased and the forward extraction rate decreased. The effect of pH on empty reverse micelles was not significant. However, the effect of pH on the full reverse micelle size and forward extraction rate were significant. Its forward extraction rate increased to the maximum39.6% at pH 7.5. The increase of the salt concentration of a buffer solution in a certain range decreased the size of empty and full reverse micelles and reduced the forward extraction rate of peanut protein. Ionic species had important effects on reverse micelles and peanut protein extraction. An increase in the amount of buffer solution enlarged the empty reverse micelle size in 0.03%-0.11%(V/V). However, it did not translate to a larger reverse micelle size. The size of the empty reverse micelles containing K_2SO_2 reached 24.1 nm with a 0.19%(V/V) buffer solution added. The sizes of the full reverse micelles were larger than those of the empty reverse micelles after forward extraction. However, maximum sizes were achieved with the addition of a 0.03%(V/V) buffer solution. The amount of 0.03%(V/V) buffer solution added was appropriate for extracting peanut protein.

Inventory control model based on external and interior reverse logistics

To improve the inventory control strategy for enterprise and optimize inventory control parameters of existing external and interior reverse logistics, a multi-resource inventory control model is proposed to better simulate the logistics fact, which is aimed at periodic inventory checking and pull mode of inventory control strategy, based on the return product arrival time obeying Poisson distribution, the return product employing lotsize process and the nonzero lead time of manufaeturinge/remanufacturing. The rational cost function with multiple constraints is employed to describe the inventory model. The genetic algorithm is employed to solve the inventory cost function to obtain the optimal solution of inventory checking periods, safe inventory point, product lot-sizes and process lot-sizes of return product. An example is presented to prove the feasibility and validity of the proposed method. Moreover, the influence of manufacturing/remanufacturing lead time and reuse rate of return production on the inventory control strategy of enterprise is analyzed.

Deep Learning Based Model Predictive Control for a Reverse Osmosis Desalination Plant

Reverse Osmosis (RO) desalination plants are highly nonlinear multi-input-multioutput systems that are affected by uncertainties, constraints and some physical phenomena such as membrane fouling that are mathematically difficult to describe. Such systems require effective control strategies that take these effects into account. Such a control strategy is the nonlinear model predictive (NMPC) controller. However, an NMPC depends very much on the accuracy of the internal model used for prediction in order to maintain feasible operating conditions of the RO desalination plant. Recurrent Neural Networks (RNNs), especially the Long-Short-Term Memory (LSTM) can capture complex nonlinear dynamic behavior and provide long-range predictions even in the presence of disturbances. Therefore, in this paper an NMPC for a RO desalination plant that utilizes an LSTM as the predictive model will be presented. It will be tested to maintain a given permeate flow rate and keep the permeate concentration under a certain limit by manipulating the feed pressure. Results show a good performance of the system.

Reversible Semi-Fragile Watermarking Technique for Integrity Control of Relational Database

Reversible watermarking schemes for relational database are usually classified into two groups: robust schemes and fragile schemes. The main limitation of existing reversible fragile methods is that they cannot differentiate between legal and malicious modifications. In this paper, we introduce a novel lossless semi-fragile scheme based on prediction-error expansion for content protection of relational database. In the proposed method, all attributes in a database relation are first classified according to their sensitivity to legitimate updates. Then, the watermark is embedded by expanding the prediction error of the two least significant digits of securely selected attributes. At watermark extraction, the proposed method has the ability to fully restore the original data while detecting and localizing tampering. The applicability of our method is demonstrated theoretically and experimentally.

Reverse-transformation austenite structure control with micro/nanometer size

To control the reverse-transformation austenite structure through manipulation of the micro/nanometer grain structure, the influences of cold deformation and annealing parameters on the microstructure evolution and mechanical properties of 316L austenitic stainless steel were investigated. The samples were first cold-rolled, and then samples deformed to different extents were annealed at different temperatures. The microstructure evolutions were analyzed by optical microscopy, scanning electron microscopy (SEM), magnetic measurements, and X-ray diffraction (XRD); the mechanical properties are also determined by tensile tests. The results showed that the fraction of stain-induced martensite was approximately 72% in the 90% cold-rolled steel. The micro/nanometric microstructure was obtained after reversion annealing at 820-870A degrees C for 60 s. Nearly 100% reversed austenite was obtained in samples annealed at 850A degrees C, where grains with a diameter ae<currency> 500 nm accounted for 30% and those with a diameter > 0.5 mu m accounted for 70%. The micro/nanometer-grain steel exhibited not only a high strength level (approximately 959 MPa) but also a desirable elongation of approximately 45%.

Intravascular ultrasound-guided “extended” reverse controlled antegrade and retrograde subintimal tracking technique using a cutting balloon for recanalizing chronic coronary total occlusion with a side branch

Percutaneous coronary intervention (PCI) of chronic total occlusion (CTO) represents the most technically challenging procedure in contemporary interventional cardiology.[1] Blunt lesions and presence of proximal side branch are considered to be strong predictors of reduced technical success.[ 2,3] For such lesions, the antegrade approach may not be feasible or desirable, and the retrograde approach can be used as the initial crossing strategy. However, when treating the blunt CTO with a large side branch proximal to the occlusion, the side branch might be occluded after stent implantation if the retrograde guidewire passed the occluded segment through the subintimal space and re-entered into the true lumen at the opposite side of the side branch.[4] We reported a useful method to solve the above issue which utilizes intravascular ultrasound (IVUS) to guide “extended” reverse controlled antegrade and retrograde subintimal tracking (CART) technique with a cutting balloon.

Multi-objective Optimization of Controller for Process with Reverse Response and Dead Time

Due to the difficulty of controlling the process with inverse response and dead time,a Multi-objective Optimization based on Genetic Algorithm (MOGA) method for tuning of proportional-integral-derivative (PID) controller is proposed. The settings of the controller are valued by two criteria,the error between output and reference signals and control moves. An appropriate set of Pareto optimal setting of the PID controller is founded by analyzing the results of Pareto optimal surfaces for balancing the two criteria. A high order process with inverse response and dead time is used to illustrate the results of the proposed method. And the efficiency and robustness of the tuning method are evident compared with methods in recent literature.

Discussion on Reverse Design of Components with Complex Curved Surface and Computer Numerical Control Machining

With the continuous development and advancement of science and technology,the work of tool path planning has received extensive attention.Among them,curved surface generation and data processing are the focus of management and design,which necessitate the full application of reverse design of complex curved surface components to complete numerical control processing,effective optimization and upgrading,integration the tasks of point cloud data collection,and point cloud data processing to ensure that the corresponding computer numerical control machining model can exert its actual value.This paper briefly analyzes the basic principles of curved surface reconstruction as well as discusses the reverse design of complex curved components and the experimental processes and results that involved computer numerical control machining,which serves the purpose as reference only.

Improvement of PV/T Based Reverse Osmosis Desalination Plant Performances Using Fuzzy Logic Controller

Photovoltaic based reverse osmosis desalination systems (PV/RO) present an effective method of water desalination especially in remote areas. The increase of the feed water temperature leads to an amelioration of the plant performances. Photovoltaic Thermal Collector (PV/T) represents an ideal power source as it provides both electric and thermal energies for the reverse osmosis process. Nevertheless, PV/T based RO plants should be controlled in order to solve operation problems related to electrical efficiency, reverse osmosis membrane, produced water and the rejected salts. This paper suggests a fuzzy logic controller for the flow rate of the circulating fluid into the PV/T collectors so as to ameliorate the system performances. The designed controller has improved the PV/T field electrical efficiency and preserved the reverse osmosis membrane which upgrades the system productivity. LABVIEW software is used to simulate the controlled system and validate the effectiveness of the controller.

Design of speed controller for electronic fuel injection gasoline generator based on feed-forward PID control

As for the application of electronic fuel injection （EFI） system to small gasoline generator set, mechanical speed controller cannot be coupled with EFI system and has the shortcomings of lagged regulation and poor accuracy, a feed-forward control strategy based on load combined with proportional-integral-differential （PID） control strategy was proposed, and a digital speed controller applied to the electrical control system was designed. The detailed control strategy of the controller was intro- duced. The hardware design for the controller and the key circuits of motor driving, current sampling and angular signal captu- ring were given, and software architecture was discussed. Combined with a gasoline generator set mounted with EFI system, the controller parameters were tuned and optimized empirically by hardware in loop and bench test methods. Test results show that the speed deviation of generator set is low and the control system is stable in steady state; In transient state the control system responses quickly, has high stability under mutation loads especially when suddenly apply and remove 100% load, the speed deviation is within 8% of reference speed and the transient time is less than 5 s, satisfying the ISO standard.

Compound control for speed and tension multivariable coupling system of reversible cold strip mill

To weaken the nonlinear coupling influence among the variables in the speed and tension system of reversible cold strip mill, a compound control(CC) strategy based on invariance principle was proposed. Firstly, invariance principle was used to realize static decoupling between the speed and tension of reversible cold strip mill. Then, considering the influence caused by the time variation of steel coil radius and rotational inertia of the left and right coilers, as well as the uncertainties, a CC strategy that is composed of extended state observer(ESO) and global sliding mode control(GSMC) with backstepping adaptive was proposed,which further realized dynamic decoupling and coordination control for the speed and tension system. Theoretical analysis shows that the resulting closed-loop system is global bounded stable. Finally, the simulation was carried out on the speed and tension system of a 1422 mm reversible cold strip mill by using the actual data, and through the comparison of the other control strategies, validity of the proposed CC strategy was shown by the results.

Preparation of Highly Concentrated Silver Nanoparticles in Reverse Micelles of Sucrose Fatty Acid Esters through Solid-Liquid Extraction Method

Silver nanoparticles were synthesized in reverse micelles consisting of sucrose fatty acid esters by dissolving reactant powder in the water pool of reverse micelles through the solid-liquid extraction. Silver nanoparticles having various sizes and shapes were obtained at high concentration. The size of silver nanoparticles was controlled by reaction temperature. Moreover, the size of silver nanoparticles was dependent upon the average esterification degree of sucrose fatty acid esters forming reverse micelles. The wavelength in the peaks, which corresponded upon the localized surface plasmon resonance of resultant silver nanoparticles, was correlated with their sizes.

Stabilization control of a bumblebee in hovering and forward flight

Our previous study shows that the hovering and forward flight of a bumblebee do not have inherent stability （passive stability）. But the bumblebees are observed to fly stably. Stabilization control must have been applied. In this study, we investigate the longitudinal stabilization control of the bumblebee. The method of computational fluid dynamics is used to compute the control derivatives and the techniques of eigenvalue and eigenvector analysis and modal decomposition are used for solving the equations of motion. Controllability analysis shows that at all flight speeds considered, although inherently unstable, the flight is controllable. By feedbacking the state variables, i.e. vertical and horizontal velocities, pitching rate and pitch angle （which can be measured by the sensory system of the insect）, to produce changes in stroke angle and angle of attack of the wings, the flight can be stabilized, explaining why the bumblebees can fly stably even if they are passively unstable.

Reversed portal flow: Clinical influence on the long-term outcomes in cirrhosis

AIM: To elucidate the natural history and the longitudinal outcomes in cirrhotic patients with non-forward portal flow(NFPF).METHODS: The present retrospective study consisted of 222 cirrhotic patients(120 males and 102 females; age, 61.7 ± 11.1 years). The portal hemodynamics were evaluated at baseline and during the observation period using both pulsed and color Doppler ultrasonography. The diameter(mm), flow direction, mean flow velocity(cm/s), and mean flow volume(m L/min) were assessed at the portal trunk, the splenic vein, the superior mesenteric vein, and the collateral vessels. The average values from 2 to 4 measurements were used for the data analysis. The portal flow direction was defined as follows: forward portal flow(FPF) for continuous hepatopetal flow; bidirectional flow for to-and-fro flow; and reversed flow for continuous hepatofugal flow. The bidirectional flow and the reversed flow were classified as NFPF in this study. The clinical findings and prognosis were compared between the patients with FPF and those with NFPF. The median follow-up period was 40.9 mo(range, 0.3-156.5 mo).RESULTS: Twenty-four patients(10.8%) demonstrated NFPF, accompanied by lower albumin level, worse ChildPugh scores, and model for end-stage liver disease scores. The portal hemodynamic features in the patients with NFPF were smaller diameter of the portal trunk;presence of short gastric vein, splenorenal shunt, or inferior mesenteric vein; and advanced collateral vessels(diameter > 8.7 mm, flow velocity > 10.2 cm/s, and flow volume > 310 m L/min). The cumulative incidence rates of NFPF were 6.5% at 1 year, 14.5% at 3 years, and 23.1% at 5 years. The collateral vessels characterized by flow velocity > 9.5 cm/s and those located at the splenic hilum were significant predictive factors for developing NFPF. The cumulative survival rate was significantly lower in the patients with NFPF(72.2% at 1 year, 38.5% at 3 years, 38.5% at 5 years) than in those with forward portal flow(84.0% at 1 year, 67.8% at 3 years, 54.3% at 5 years, P = 0.0123) using the Child-Pugh B and C classifications.CONCLUSION: NFPF has a significant negative effect on the prognosis of patients with worse liver function reserve, suggesting the need for careful management.

Reversing multiple age-related pathologies by controlling the senescence-associated secretory phenotype of stem cells

Regenerative medicine by cell transplantation is a novel therapy for treating end-stage organ failure and tissue damage. Cell-based therapy based on the transplantation of neural stem/progenitor cells （NSPCs） represents an attractive strategy for the treatment of neurodegenerative diseases, but obtaining large numbers of these cells is difficult and their differentiation potential is strictly restricted in a spatiotemporally-regulated manner during central nervous system （CNS） development. Therefore, embryonic stem cells and induced pluripotent stem cells represent an attractive alternative for cell-transplantation therapy in regenerative medicine.