Simple PID Parameter Tuning Method Based on Outputs of the Closed Loop System

Most of the existing PID parameters tuning methods are only effective with pre-known accurate system models, which often require some strict identification experiments and thus infeasible for many complicated systems. Actually, in most practical engineering applications, it is desirable for the PID tuning scheme to be directly based on the input-output response of the closed-loop system. Thus, a new parameter tuning scheme for PID controllers without explicit mathematical model is developed in this paper. The paper begins with a new frequency domain properties analysis of the PID controller. After that, the definition of characteristic frequency for the PID controller is given in order to study the mathematical relationship between the PID parameters and the open-loop frequency properties of the controlled system. Then, the concepts of M-field and θ-field are introduced, which are then used to explain how the PID control parameters influence the closed-loop frequency-magnitude property and its time responses. Subsequently, the new PID parameter tuning scheme, i.e., a group of tuning rules, is proposed based on the preceding analysis. Finally, both simulations and experiments are conducted, and the results verify the feasibility and validity of the proposed methods. This research proposes a PID parameter tuning method based on outputs of the closed loop system.

Carbon dioxide/calcium oxide responsive behavior and application potential of amine emulsion

Green and low cost CO_(2) and CaO were used to stimulate amine emulsions to reveal the responsive behavior of amine emulsions.On this basis,oil-based drilling fluids responsive to CO_(2) and CaO were formulated and their properties were evaluated.The results showed that the amine emulsions inversed from water-in-oil state to oil-in-water state readily and their rheological behavior underwent transitions of decreasing,rising again and decreasing again via induction by CO_(2).These CO_(2) responsive behaviors could be reversed by CaO.Oil-based drilling fluids prepared based on the amine emulsions with oil-water volume ratios of 50:50 to 70:30,densities of 1.4-2.0 g/cm^(3) had good rheological and filtration properties at 160℃;and be readily cleaned up using CO_(2) bubbling.The useless solid phase with low density could be removed efficiently via reducing the viscosity of emulsion by CO_(2) and the residual liquid phase could be restored to the original state by CaO and reused to prepare drilling fluid.The mechanisms analysis indicated that CO_(2)/CaO induced the reversible conversion between amine emulsifiers and their salts,which enabled the reversible regulation of both the hydrophilic-lipophilic balance of amine emulsifiers and the emulsion particles’size and finally caused the controllable-reversion of the form and rheology of amine emulsion.

Study on Water Pollution and Control in China

In recent years, water pollution has become increasingly serious in China. Meanwhile, decrease of water bodies in quality, frequent pollution incidents, safety of drinking water and water shortage have become prominent day by day. However, water pollution can not be controlled effectively. To clear underlying reasons for increasingly worsening water environment, the external effects of pollution behavior and fictitious property right of pollution control bodies were analyzed using property right theory, and then internal reasons for serious water pollution were discussed. Fi- nally, control measures of water pollution were put forward.

Modeling of Microstructure Evolution and Mechanical Properties of Steel Plates Produced by Thermo-Mechanical Control Process and Its On-line Application

An integrated metallurgical model was developed to predict microstructure evolution and mechanical properties of low-carbon steel plates produced by TMCP. The metallurgical phenomena occurring during TMCP and mechanical properties were predicted for different process parameters. In the later passes full recrystallization becomes difficult to occur and higher residual strain remains in austenite after rolling. For the reasonable temperature and cooling schedule, yield strength of 30 mm plain carbon steel plate can reach 310 MPa. The first on-line application of prediction and control of microstructure and properties (PCMP) in the medium plate production was achieved. The predictions of the system are in good agreement with measurements.

Phase Control of Transient Optical Properties of Double Coupled Quantum-Dot Nanostructure via Gaussian Laser Beams

We theoretically analyze the transient properties of a probe field absorption and dispersion in a coupled semiconductor double-quantum-dot nanostructure.We show that in the presence of the Gaussian laser beams,absorption and dispersion of the probe field can be dramatically influenced by the relative phase between applied fields and intensity of the Gaussian laser beams.Transient and steady-state behaviors of the probe field absorption and dispersion are discussed to estimate the required switching time.The estimated range is between 5-8 ps for subluminal to superluminal light propagation.

Focusing Properties of Partially Coherent Controllable Dark-Hollow Beams through a Thin Lens

Analytical propagation formulas are derived for partially coherent controllable dark-hollow beams （CDHBs） through a thin lens based on the generalized Huygens-Fresnel integral. The expressions of the position for maximum irradiance on-axis and the relative focal shift are evaluated by the analytical propagation formulas. Our numerical results show that both the relative focal shift and the effective beam width of focused partially coherent CDHBs are mainly determined by the initial transverse coherence width 6g and the Fresnel number Nw, which are also affected by the changes of both the dark-size adjusting parameter p and the order N of CDHBs.

Controllable Synthesis and Magnetic Properties of Monodisperse Fe_3O_4 Nanoparticles

Magnetite （Fe3O4） nanoparticles with different sizes and shapes are synthesized by the thermal decomposition method. Two approaches, non-injection one-pot and hot-injection methods, are designed to investigate the growth mechanism in detail. It is found that the size and shape of nanoparticles are determined by adjusting the precursor concentration and duration time, which can be well explained by the mechanism based on the LaMer model in our synthetic system. The monodisperse Fe3O4 nanoparticles have a mean diameter from 5nm to 16nm, and shape evolution from spherical to triangular and cubic. The magnetic properties are size-dependent, and Fe3O4 nanoparticles in small size about 5 nm exhibit superparamagnetie properties at room temperature and maximum saturation magnetization approaches to 78 emu/g, whereas Fe3O4 nanoparticles develop ferromagnetic properties when the diameter increases to about 16nm.

Soft Sensors for Property‑Controlled Multi‑Stage Press Hardening of 22MnB5

In multi-stage press hardening,the product properties are determined by the thermo-mechanical history during the sequence of heat treatment and forming steps.To measure these properties and finally to control them by feedback,two soft sensors are developed in this work.The press hardening of 22MnB5 sheet material in a progressive die,where the material is first rapidly austenitized,then pre-cooled,stretch-formed,and finally die bent,serves as the framework for the development of these sensors.To provide feedback on the temporal and spatial temperature distribution,a soft sensor based on a model derived from the Dynamic mode decomposition(DMD)is presented.The model is extended to a parametric DMD and combined with a Kalman filter to estimate the temperature(-distribution)as a function of all process-relevant control vari-ables.The soft sensor can estimate the temperature distribution based on local thermocouple measurements with an error of less than 10°C during the process-relevant time steps.For the online prediction of the final microstructure,an artificial neural network(ANN)-based microstructure soft sensor is developed.As part of this,a transferable framework for deriving input parameters for the ANN based on the process route in multi-stage press hardening is presented,along with a method for developing a training database using a 1-element model implemented with LS-Dyna and utilizing the material model Mat248(PHS_BMW).The developed ANN-based microstructure soft sensor can predict the final microstructure for specific regions of the formed and hardened sheet in a time span of far less than 1 s with a maximum deviation of a phase fraction of 1.8%to a reference simulation.

An in situ growth method for property control of LPCVD polysilicon film

Polysilicon films deposited by low-pressure chemical vapor deposition (LPCVD) exhibit large residual stress and stress gradient, depending on the deposition condition. An in situ growth method based on multilayer concept is presented to control the property for as-deposited polysilicon. A 3-μm thick polysilicon film with nine layers structure is demonstrated under the detailed analysis of multi-layer theory and material characteristic of polysilicon. The results show that a 3-μm-thick polysilicon film with 8-MPa overall residual tensile stress and 2.125-MPa/μm stress gradient through the film thickness is fabricated successfully.

Simultaneous structure and luminescence property control of barium carbonate nanocrystals through small amount of lanthanide doping

Rare earth doping has been widely applied in many functional nanomaterials with desirable properties and functions,which would have a significant effect on the growth process of the materials.However,the controlling strategy is limited into high concentration of lanthanide doping,which produces concentration quenching of the lanthanide ion luminescence with an increase in the Ln^(3+)concentration,resulting in lowering the fluorescence quantum yield of lanthanide ion.Herein,for the first time,we demonstrate simultaneous control of the structures and luminescence properties of BaCO_3nanocrystals via a small amount of Tb^(3+)doping strategy.In fact,Tb^(3+)would partially occupy Ba^(2+)sites,resulting in the changes to the structures of the BaCO_3nanocrystals,which is primarily determined by charge modulation,including the contributions from the surfaces of crystal nuclei and building blocks.These structurally modified nanocrystals exhibit tunable luminescence properties,thus emerging as potential candidates for photonic devices such as light-emitting diodes and color displays.

Chronic training status affects muscle excitation of the vastus lateralis during repeated contractions

This study examined electromyographic amplitude(EMGRMS)-force relationships during repeated submaximal knee extensor muscle actions among chronic aerobically-(AT),resistance-trained(RT),and sedentary(SED)individuals.Fifteen adults(5/group)attempted 20 isometric trapezoidal muscle actions at 50%of maximal strength.Surface electromyography(EMG)was recorded from vastus lateralis(VL)during the muscle actions.For the first and last successfully completed contractions,linear regression models were fit to the log-transformed EMGRMS-force relationships during the linearly increasing and decreasing segments,and the b terms(slope)and a terms(antilog of y-intercept)were calculated.EMGRMS was averaged during steady force.Only the AT completed all 20 muscle actions.During the first contraction,the b terms for RT(1.3010.197)were greater than AT(0.9100.123;p?0.008)and SED(0.9120.162;p?0.008)during the linearly increasing segment,and in comparison to the linearly decreasing segment(1.0180.139;p?0.014),respectively.For the last contraction,the b terms for RT were greater than AT during the linearly increasing(RT?1.3730.353;AT?0.8830.129;p?0.018)and decreasing(RT?1.5260.328;AT?0.9700.223;p?0.010)segments.In addition,the b terms for SED increased from the linearly increasing(0.9680.144)to decreasing segment(1.2680.126;p?0.015).There were no training,segment,or contraction differences for the a terms.EMGRMS during steady force increased from the first-([64.0851.68]μV)to last-contraction([86.7349.55]μV;p?0.001)collapsed across training statuses.The b terms differentiated the rate of change for EMGRMS with increments in force among training groups,indicating greater muscle excitation to the motoneuron pool was necessary for the RT than AT during the linearly increasing and decreasing segments of a repetitive task.

Composite microcapsules with enhanced mechanical stability and reduced active ingredient leakage

A calcium shellac （CS） matrix was used to encapsulate polymeric melamine formaldehyde microcapsules （A） or CaCO3 nanoparticles-stabilized microcapsules （B）, both of which encapsulated an oil-based active ingredient, producing A-CS or B-CS composite microcapsules. The mechanical properties and oil release profiles of the composite microcapsules were evaluated. The composite microcapsules showed enhanced mechanical stability and reduced leakage of the active ingredient hv one order of magnitude.

Effect of sodium alginate/phosphate-stabilized amorphous calcium carbonate nanoparticles on chitosan membranes

Biodegradable chitosan(CS)films can meet the demand for sustainable development.However,the performance of pure CS membrane still exists a particular gap compared with the traditional film.Inorganic nanomaterials with the controllable release are added to improve its physical and chemical properties.Herein,a series of CS/phosphate-stabilized amorphous calcium carbonate(CS/ACCP)and CS/sodium alginate/ACCP(CS/Alginate/ACCP)composite films were prepared by the flow method.The effects of ACCP and Alginate/ACCP nanoparticles on the physical and chemical properties of the composite membrane were investigated.The results showed that the composite nanoparticles could significantly improve CS film’s compactness,hydrophobicity,and mechanical properties and enhance its ultraviolet(UV)blocking ability,water resistance,and water vapor blocking ability.When the number of nanoparticles was 8%,the mechanical properties of the CS composite membrane reached optimum value,and the comprehensive performance was better.In addition,the controlled-release properties of CS composite membranes were also studied,and the antioxidant,antibacterial,biocompatibility,and fresh-keeping effects of the composite membranes were explored.The results indicated that the CS composite membranes had not only excellent bacteriostatic(72%)properties(Escherichia coli)but also presented well fruit preservation(15 days)properties(sugar orange).In particular,the controlled release range of CS composite membrane at 12 h was between 30%and 90%,which provided a theoretical basis for its use as an edible membrane.Therefore,based on ACCP and Alginate/ACCP nanoparticles,CS composite membranes with more excellent application value in the biological field were prepared through further optimization design.

Applications of the crystallization process in the pharmaceutical industry

The applications of the crystallization technique in the pharmaceutical industry as a purification and separation process for the isolation and synthesis of pure active pharmaceutical ingredients(API),co-crystals,controlled release pulmonary drug delivery,and separation of chiral isomers are briefly discussed using a few case studies.The effect of process variables and solvent on the polymorphism and morphology of stavudine is discussed.The implementation of external control in the form of feedback and real-time optimal control using cooling and antisolvent crystallization of paracetamol in water-isopropyl alcohol is introduced.Two methods to prepare micronsized drug particles,namely,micro-crystallization and polymer-coated API-loaded magnetic nanoparticles for pulmonary drug delivery,are discussed.The significance of co-crystals in drug administration is highlighted using the theophylline-nicotinamide co-crystal system.Resolution of chloromandelic acid derivatives,a racemic compound,is achieved using direct crystallization and diastereomeric salts crystallization.The crystal structures of diastereomeric salts of chloromandelic acid and phenylethylamine are determined.The structure comparison between the less soluble and more soluble salts shows that weak interactions such as CH/πinteractions and van der Waals forces contribute to chiral recognition when the hydrogen bonding patterns are similar.

Finite Sample Properties of Virtual Reference Feedback Tuning Control

In this paper, finite sample properties of virtual reference feedback tuning control are considered, by using the theory of finite sample properties from system identification. To design a controller in closed loop system structure, the idea of virtual reference feedback tuning is proposed to avoid the identification process corresponding to the plant model. After constructing one identification cost without any knowledge of plant model, the author derives one bound on the difference between the expected identification cost and its sample identification cost under the condition that the number of data points is finite. Also the correlation between the plant input and external noise is considered in the derivation of this bound. Furthermore, the author continues to derive one probability bound to quantify this difference by using some probability inequalities and control theory.