Stimulus-response Method Research Articles

FedSiM: a similarity metric federal learning mechanism based on stimulus response method with Non-IID data

Federal learning based on parameter sharing under the assumption that the data obey independent identical distribution (IID has already achieved good results in areas such as fault diagnosis. Data collected by the decentralized devices often do not obey IID. However, when faced with the scenario of client data obeying Non-IID distribution, its diagnostic accuracy is usually weak. Based on this, we did an investigation on the mechanism causing this phenomenon and found that it was attributed to the weight shift of the network. Therefore, based on the stimulus response principle, we investigated the network similarity of federal clients under different data distributions and explain the reasons for the weight shift. Firstly, it was pointed out that there are differences in the regions where the network is activated when performing different classification tasks. Then, similarity metric federal learning (FedSiM) was proposed based on the principle that there are differences between the activated regions. Finally, experiments were designed on the Case Western Reserve University bearing failure dataset for different degrees of IID cases. The results show that FedSiM can improve the diagnostic accuracy by 15.8 percentage points in the case of Non-IID, and a few shared FedSiM methods to further improve the accuracy were also given.

Current Limitations for Predicting Liquid Dispersion in Continuous Flow Bubble Columns Using CFD

Liquid-phase dispersion in a continuous flow bubble column was studied using computational fluid dynamics (CFD) and different combinations of turbulence and biphasic models. The results were compared with the experimental data obtained by the stimulus-response method in an air-water pilot-scale bubble column (2 m tall, 0.234 m internal diameter). Two flow combinations were examined: high flow rates of 3.2 m3 h−1 and 4.5 m3 h−1 and low flow rates of 1.98 m3 h−1 and 0.954 m3 h−1 for water and air, respectively. The objective was to evaluate commercial CFD 16.1 software to predict flow behavior beyond macroscale parameters such as hold-up or mixing time. The turbulence models that best replicated the experimental tracer dispersion were large eddy simulation-type models: scale-adaptive simulation (SAS) and shear stress transport-SAS. The simulations qualitatively predicted the tracer concentration with time but were unable to reveal the small-scale perturbations in the biphasic system. The predicted tracer residence time was double or triple the measured times for low and high flow, respectively.

Preparation of CO2 responsive cellulose composite adsorbent and its application in protein separation

AbstractThe separation of the proteins is of great theoretical and practical importance for biotechnological application. Considering the requirement of non‐destructive separation, the stimulus–response method is an alternative to the separation of protein. In this work, a cellulose‐based composite with CO2 stimulus–response property is prepared by a simple coprecipitation of poly (N, Nˊ‐diethylamino ethyl methacrylate)‐co‐poly (hydroxyethyl methacrylate) (PDH) and cellulose mixture solution. Subsequently, these composites as the adsorption medium are used to separate the bovine serum albumin (BSA, as the model protein) from solution through stimulus–response course (by CO2/N2 alternation). The results indicate that the ratio of the copolymers/cellulose composite have an obvious effect on the separation of BSA. The average maximum adsorption capacity can get to 562.6 mg/g, and the composites exhibits good adsorption/desorption cycling characteristics. After the composite materials are cycled for three times, the adsorption capacity can still decrease to 300 mg/g. Due to its high adsorption capacity and low preparation cost, the composite is expected to be widely used in industry.

The role of stimulus features and response method on feature-continuous motion perception

The role of stimulus features and response method on feature-continuous motion perception

Troubleshooting in a full-scale wastewater treatment plant: what can be learnt from tracer tests

The experimental assessment of the actual reactor hydrodynamic behavior is aimed at detecting possible deviations from the design configuration, as well as suggesting corrective/improving modifications, efficacy of which can be also assessed in the aftermath. The hydrodynamic scheme can be defined by means of tracer tests (stimulus–response method) used for detecting the residence time distribution curve. This study shows the results of three hydrodynamic tests performed on a wastewater treatment plant half-line, in which a biological process (denitrification and oxidation–nitrification) is carried out. Hydrodynamic faults (in terms of dead space and/or flow bypass) were identified, and consequent actions suggested (i.e., change in submerged mixers orientation in the reactors; sinking of the final section of the sludge recirculation pipe below the free surface to avoid foaming phenomena; introduction of new mixed liquor recirculation lines). These actions, together with a careful selection of wastes to be treated, led to an improvement of the overall process performance.

Open-cell foams as beds in multiphase reactors: Residence time distribution and mass transfer

The hydrodynamic properties (residence time distribution and holdup), gas-liquid surfaced area and mass transfer coefficients for two foamed fixed beds are measured and compared with correlations proposed in the literature. Two foam materials, an Al2O3 foam of 20 ppi and a β-SiC foam of 7 ppi, were considered and experiments were performed in the trickle regime varying liquid and gas superficial velocities, in the ranges 0.001–0.005m/s and 0.045–0.079m/s, respectively.Residence time distributions were measured by the stimulus-response method using a pulse tracer. This technique provides information about the liquid hold-up and the flow pattern, including the degree of mixing. The deviations from ideal plug flow have been modelled using the dispersion model.The gas-liquid mass transfer and effective surface area have been studied using the method of Danckwerts, based on the reaction between CO2 and NaOH.

Study of the influence of boundary conditions, non ideal stimulus and dynamics of sensors on the evaluation of residence time distributions

The study of the residence time distribution is usually made in order to diagnose the hydrodynamic behaviour of the equipment. This paper reports on the residence time distribution according to six combinations of the open and closed boundary conditions, which are compared in order to determine an appropriate equation to fit experimental data from the stimulus-response method. The residence time distribution under laminar flow is analysed and the mathematical modelling of the pure convection regime, zone of axial dispersion and intermediate case is discussed. The disturbances in the residence time distribution produced by a non-ideal impulse and also by the dynamic behaviour of the sensor are quantified and the errors in its evaluation are given.

A novel hybrid technique for leak detection and location in straight pipelines

Underground gas pipeline leaks can lead to tremendous economic loss and human injury. Therefore, it is vital to detect and locate the pipeline leaks in time to maintain the normal operation. However, continuous leak-detection methods of require a lot of manpower, marterial resources and financial supports, while other detecting activities break the normal operation of the pipeline. Hybrid techniques consisting of two or more different technologies appear to be the most probable future trend in pipeline leak detection and location field. In this paper, a novel hybrid technique based on real-time transient modeling method and negative pressure wave method is proposed. An experimental bench for straight pipelines is set up to evaluate the performance of the proposed hybrid technique, and corresponding experimental test programs for gas leak detection and location are designed and conducted. A mathematical model for the transient flow in pipelines has been established and solved under different boundary conditions. The occurrence of a leak can be preliminarily judged by the difference between the measured data and the predicted value from the model; and the changing patterns of parameters under the leak condition, the valve-opening adjusting condition and the compressor-speed regulating condition are investigated to identify the leak condition out of the operational changes. Finally, the leak point is located using the stimulus-response method. Results show that the hybrid technique is successful in detecting and locating gas pipeline leaks. It is expected that the research outcomes can serve as a technical base for the safe operation of gas supply networks.

Locating Gas Pipeline Leakage Based on Stimulus-response Method

Gas pipeline leakage leads to significant environmental damages, industrial hazards and personal injuries, so detecting and locating the leakage location without delay is essential to lighten or avoid its harms. The stimulus-response method, a newly proposed technique of pipeline leakage detection and location has received much attention for its benefit of strong detecting signal and high positioning accuracy. In this paper, firstly, a complete set of gas pipeline leakage experimental device was built on the basis of stimulus-response method. Secondly, three leakage points were designed and tested to investigate the positioning accuracy. Finally, the impacts of aperture size and incentive intensity on positioning result were evaluated, and the detectable aperture size and minimum incentive intensity were determined. The results show that under fully-closed condition of the terminal valve, the minimum pore size that can be detected is 2mm in the experimental tests (with an aperture ratio of 4 percent). It is expected that the outcomes can provide reference for improving localization methods of gas pipeline leakage.

Characterization of a bipolar parallel-plate electrochemical reactor for water disinfection using low conductivity drinking water

A reactor was built, experimentally studied and modelled having six bipolar electrodes placed between the terminal ones, all of them were RuO2/IrO2 on a Ti sheet. The interelectrode gap was 1.5mm. Plastic plates were optionally arranged in the inlet and outlet to the electrodes to produce entrance or exit regions. The Laplace equation was numerically solved for the solution phase to obtain the current and potential distribution. The calculations performed without entrance and exit regions show that the current distribution is pronounced at the thickness of the electrodes and at the electrode edges. The presence of the entrance and exit regions covers the electrode thickness, increases the current distribution and diminishes the leakage current. The hydrodynamics of the reactor was analyzed by the stimulus–response method and the best behaviour was obtained when the equipment was filled with glass beads. This reactor was tested analyzing the in-line production of sodium hypochlorite from drinking water. In a typical galvanostatic experiment, carried out at 10.3A, with a volumetric flow rate of 2dm3min−1 the hypochlorite concentration at the exit was 25mgdm−3. In this case, the applied potential difference was 128V and the current efficiency was 4.3%.

INITIATION OF THE DESA TANGGUH BENCANA THROUGH STIMULUS-RESPONSE METHOD

The model of “desa tangguh bencana” (disaster resilient village) has to be initiated through stimulus program. Social values existed in local community are basic capital in establishing disaster resilient village. Mapping the site properties and characteristics is an essential step to capture the community’s level of vulnerability and capacity. Establishment of “desa tangguh bencana” is one of methods to involve local community in community based disaster risk reduction (CBDRR). The initiation of disaster resilient in Pagubugan Kulon was done through stimulus-response method to introduce safe and resilient culture. Building up the good understanding of disasters becomes one important way to rise up the community preparedness. The community response in Pagubugan Kulon to the disaster stimuli is the establishment of “desa tangguh bencana pratama”.

Paste Residence Time in a Spouted Bed Dryer. IV: Effect of the Inert Particle Size Distribution

The residence time distribution and mean residence time of a 10% sodium bicarbonate solution that is dried in a conventional spouted bed with inert bodies were measured with the stimulus-response method. Methylene blue was used as a chemical tracer, and the effects of the paste feed mode, size distribution of the inert bodies, and mean particle size on the residence times and dried powder properties were investigated. The results showed that the residence time distributions could be best reproduced with the perfect mixing cell model or N = 1 for the continuous stirred tank reactor in a series model. The mean residence times ranged from 6.04 to 12.90 min and were significantly affected by the factors studied. Analysis of variance on the experimental data showed that mean residence times were affected by the mean diameter of the inert bodies at a significance level of 1% and by the size distribution at a level of 5%. Moreover, altering the paste feed from dripping to pneumatic atomization affected mean residence time at a 5% significance level. The dried powder characteristics proved to be adequate for further industrial manipulation, as demonstrated by the low moisture content, narrow range of particle size, and good flow properties. The results of this research are significant in the study of the drying of heat-sensitive materials because it shows that by simultaneously changing the size distribution and average size of the inert bodies, the mean residence times of a paste can be reduced by half, thus decreasing losses due to degradation.

Evaluation of the hydrodynamic behaviour of turbulence promoters in parallel plate electrochemical reactors by means of the dispersion model

The hydrodynamic behaviour of electrochemical reactors with parallel plate electrodes is experimentally studied using the stimulus-response method either with an empty reactor or with different turbulence promoters. Theoretical results which are in accordance with the analytical and numerical resolution of the dispersion model for a closed system are compared with the classical relationships of the normalized outlet concentration for open systems and the validity range of the equations is discussed. The experimental results were well correlated with the dispersion model using glass beads or expanded plastic meshes as turbulence promoters, which have shown the most advantageous performance. The Peclet number was higher than 63. The dispersion coefficient was found to increase linearly with flow velocity in these cases.

Modeling of catalytic ozonation process in a three-phase reactor

In this research, the main objective was to determine the flow characteristics of a three-phase reactor in order to use this knowledge in the modeling of catalytic ozonation of aqueous dye solutions. Therefore, the stimulus-response method was used in the tracer experiments; thus, the degree of liquid mixing in the reactor was estimated by means of residence time distribution, Péclet number and axial dispersion coefficient in the presence and the absence of the catalyst. Experimental data were obtained by performing the catalytic ozonation of aqueous Acid Red-151(AR-151) and Remazol Brilliant Blue-R (RBBR) dye solutions, in the presence of perfluorinated-octyl-alumina (PFOA) catalyst particles at different operating conditions. The chemical oxygen demand (COD), the dye and ozone concentrations in the liquid phase were measured at the steady state along the height of the column reactor and at the exit. According to the results, it was observed that the gas-liquid reactor without the catalyst particles showed a hydrodynamic behavior equivalent to two or three completely stirred tank reactors (CSTRs) in-series for the conventional ozonation process. The presence of catalyst particles caused the flow behavior of the three phase reactor to approach to one CSTR or two CSTRs in-series depending on the gas and liquid flow rates so that the modeling of the catalytic ozonation process was done satisfactorily on that basis. The modeling results showed satisfactory agreement with the experimental ones in the prediction of outlet dye and dissolved ozone concentrations from the reactor, especially at relatively high gas velocities (Q G = 150 and 200 L h− 1) for AR-151, where the dissolved ozone concentration was not limited. However, the discrepancy was about 15% between the theory and experiment at the lower gas flow rates due to the limited ozone concentrations with respect to the dye concentrations at the high inlet dye concentration of AR-151 (C D,i = 100 mg L− 1). For RBBR, the predicted and experimental values were very close to each other since ozone limitation or dye abundance was not realized in these experiments.

Dispersion coefficient of coffee berries in vibrated bed dryer

This paper interprets the experimentally measured residence time distribution of coffee berries on a vibrated tray dryer with recycle by means of the dispersion coefficients and the Peclet number. Drying was carried out on a vibrated tray dryer operating with recycle consisting of four parts: a vertical drying tunnel, vibration system, warm air supply to the drying tunnel and recycle system of coffee berries. Using the stimulus–response method the flow behavior of the coffee berries was examined. The dispersion coefficients were calculated by the Taylor Dispersion Model and Free Dispersion Model. The differences in prediction of the dispersion coefficient between the two models were appreciable, but the more reliable values for the dispersion coefficients E z were those obtained by the Free Dispersion Model. The dispersion coefficient (Free Dispersion) ranged from 2.32 × 10 −4 to 76.81 × 10 −4 m 2/s. The average Peclet number, Pe was approximately equal to 6.5, despite greatest variation of the E z. Therefore, flow velocity variation of coffee berries was the same magnitude of the dispersion coefficient variation.

Axial dispersion of gas in a circulating fluidized bed

An axial dispersion of gas in a circulating fluidized bed was investigated in a fluidized bed of 4.0 cm I.D. and 279 cm in height. The axial dispersion coefficient of gas was determined by the stimulus-response method of trace gas of CO2. The employed particles were 0.069 mm and 0.147 mm silica-sand. The results showed that axial dispersion coefficients were increased with gas velocity and solid circulation rates as well as suspension density. The experimentally determined axial dispersion coefficients in this study were in the range of 1.0-3.5 m2/s.

Effect of Pressure and Temperature on the Axial Dispersion of Gas in a Bubbling Fluidized Bed.

The effect of pressure and temperature on the axial dispersion of gas was examined in a fluidized bed of 10 cm I.D. × 100 cm height. The employed particle was zinc titanate catalyst and particle size was 150 μm. The stimulus-response method was employed in order to determine the axial dispersion coefficient of gas in a bubbling fluidized bed. The hydrogen was used as the trace gas. The experimental results showed that the increase of pressure and temperature did not significantly change the axial dispersion coefficient in spite of significant increase of minimum fluidization velocity.

Mathematical Model of Hot Metal Desulphurization by Powder Injection

A macro kinetic analysis of the hot metal desulphurization with powder injection has led to that there are three basic parameters which determine the desulphurization rate, as well as the power utilization efficiency. They are the penetration ratio (PR) of injected powder into the melt, the residence time distribution (RTD) of injected powder in the bath, as well as the homogeneous mixing time (HMT) of the bath. Both PR and HMT have been experimentally determined with water modeling, while the RTD has been determined from either flow field information or experimental measurements of water model with stimulus-response method, arriving at the correlation formulas between the parameter and the injection operation variables as well as powder characteristics. This has enabled the development of a mathematical model to predict the desulphurization process.Based on further analysis of the mechanism and macro kinetics of the process, a mathematical model has been developed, with the three basic parameters being taken into account, to simulate the variation of [S] in hot metal with time. Water-model experiment results, flow field information and industrial data are used to determine the model parameters and verify the model, leading to the result that the prediction from the model agrees well with practical results. In addition to CaO and CaC2 powders, the use of granular Mg has been particularly included and emphasized in the model for its more and more popular application. The coupling effect of hot metal desulphurization by injection of magnesium-CaC2 mixture was discussed.

Evaluation of a stimulus-response method for distinguishing out-migrant salmonids from drifting debris for sonar counts in the Trinity River, California

A method for discriminating fish from debris in sonar counts of out-migrant salmonids was tested in the Trinity River, California. The method used induced fish movements to distinguish fish from drifting debris. Electricity and light served as stimuli and video and split-beam sonar were used to measure movements of fish (mainly juvenile chinook salmon) and debris (mainly tree leaves). Differences in fish and debris behavior were clearly observable with underwater video. Many fish darted or slowed and most fish dove, whereas debris drifted passively. Fish responded to the electric field inconsistently, and an apparent positive phototaxis was the most consistent response to stimuli. Lack of matched sonar and video observations of individual targets prevented direct testing of sonar’s ability to differentiate fish and debris in the Trinity River. However, analysis of sonar data from a similar situation in the Seton River, British Columbia, indicate that fish responses measured in the Trinity River by video were within the resolution of split-beam sonar. Split-beam position measurement error averaged ≤ 0.06 m within 5° of the acoustic axis, compared to a mean diving reaction of 0.11 m by salmonids observed with video. Proper transducer deployment, improved sonar analysis methods, and perfection of stimuli to elicit obvious and consistent fish responses are key to the success of this technique. With suitable development and validation, the stimulus-response method could become a useful tool for apportioning sonar counts among fish and debris.

Detection of protein concentrations using a pH-step titration method

A stimulus–response method based on the application of a pH step is proposed for the detection of protein immobilized in a membrane on top of an ion-sensitive field-effect transistor (ISFET). The ISFET response to a step-wise change in pH, applied at the interface between the membrane and the surrounding solution, depends on the concentration of protein immobilized in the membrane because proton-dissociation reactions of the protein cause a delayed diffusion of protons and hydroxyl ions through the membrane. Our theoretical description shows that the delay in ISFET response is linearly related to the concentration of protein immobilized in the membrane. Experiments performed with lysozyme as a model protein show the feasibility of this detection principle.