System Response Parameters Research Articles

Comparison of the Performance of Type-1 and Interval Type-2 Fuzzy PI Controllers for Liquid Level Control in a Coupled Tank System

In this study, liquid level control in a coupled tank system is realized with PI controllers whose parameters are adapted using fuzzy logic approximation methods. Type-1 fuzzy PI control, interval type-2 fuzzy PI control and classical PI+Feedforward control methods are applied to the tank system in real time for different reference liquid levels. The performances of the controllers are compared in terms of system response parameters such as rise time, settling time and overshoot percentage. In addition, the performance evaluation of the controllers over a certain period of time is also compared by calculating integral-based concepts that express error performance metrics such as integral square error (ISE), integral time square error (ITSE), integral absolute error (IAE) and integral time absolute error (ITAE). The obtained results show that the type-2 fuzzy PI controller shows the best performance, followed by type-1 fuzzy PI control and classical PI+FF controller, respectively.

Nano-selenium impacts on growth performance, digestive enzymes, antioxidant, immune resistance and histopathological scores of Nile tilapia, Oreochromis niloticus against Aspergillus flavus infection

The present study examined the impacts of varying amounts of selenium nanoparticles (Se-NPs) as a natural antioxidant and metabolic regulator on growth performance, antioxidant capacity, digestive enzymes and immune resistance of Oreochromis niloticus challenged to Aspergillus flavus infection. For 60 days, fish were fed the experimental diet of 30% crude protein up to apparent satiation three times a day. Se-NPs were added to the control diet at different levels of 0.0 (control), 0.5 (T1), 1.0 (T2) and 1.5 (T3) mg/kg diet to fed monosex Nile tilapia fingerlings with average initial weight (4.5 ± 0.5 g). Fish were randomly distributed in 12 tanks 100 L at a density of 20 fish per tank after 2-week acclimation to represent four treatments in triplicates. The results indicated that the growth indices, feed efficiency and survival rate were significantly enhanced (P < 0.05) by incorporating Se-NPs up to 1 mg/kg diet. Furthermore, the haemato-biochemical parameters, digestive enzymes activity and antioxidant capacity of the fish were significantly improved (P < 0.05) at T2. When the fish were challenged with Aspergillus flavus, a decreasing mortality rate was observed, which clearly shows that selenium nanoparticles boosted the fish’s immune response at T2. The intestinal morphology as villus length, villus width, muscular fibres layer thickness and absorption intestinal zone after challenged with A. flavus infection were considerably enhanced (P < 0.05) by incorporating all Se-NP levels. Histopathological score significantly improved (P < 0.05) for the hepatopancreatic, intestinal, gills and muscle tissues at T2. The present study concludes that selenium nanoparticles up to 1.0 mg/kg diet can be efficiently used in tilapia feed to help boost fish production, immune system response and histopathological parameters.

Dynamics and Control of a Magnetic Transducer Array Using Multi-Physics Models and Artificial Neural Networks.

A linear mechanical oscillator is non-linearly coupled with an electromagnet and its driving circuit through a magnetic field. The resulting non-linear dynamics are investigated using magnetic circuit approximations without major loss of accuracy and in the interest of brevity. Different computational approaches to simulate the setup in terms of dynamical system response and design parameters optimization are pursued. A current source operating in baseband without modulation directly feeds the electromagnet, which consists commonly of a solenoid and a horseshoe-shaped core. The electromagnet is then magnetically coupled to a mass made of soft magnetic material and attached to a spring with damping. The non-linear system is described by a linearized steady-space representation while is examined for controllability and observability. A controller using a pole placement approach is built to stabilize the element. Drawing upon the fact that coupling works both ways, enabling estimation of the mass position and velocity (state variables) by processing the induced voltage across the electromagnet, a state observer is constructed. Accurate and fast tracking of the state variables, along with the possibility of driving more than one module from the same source using modulation, proves the applicability of the electro-magneto-mechanical transducer for sensor applications. Next, a three-layer feed-forward artificial neural network (ANN) system equivalent was trained using the non-linear plant-linear controller-linear observer configuration. Simulations to investigate the robustness of the system with respect to different equilibrium points and input currents were carried out. The ANN proved robust with respect to position accuracy.

Rheological properties of pea protein isolate-amylose/amylopectin mixtures and the application in the high-moisture extruded meat substitutes

The interactions between the protein and starch molecules should play an important role in preparing the pea protein-based meat substitutes with rich meat-like fibrous structure. In this study, the pea protein isolate (PPI) was firstly mixed with the amylose/amylopectin (0:1, 1:2, 1:1, 2:1, 1:0) mixtures at the ratio of 9:1 and then extruded under high moisture condition (58%, w/w). The effects of the rheological properties of PPI-amylose/amylopectin mixtures on the system response parameters (die pressure, torque, and specific mechanical energy) and the final product qualities (the color, texture properties, in vitro digestibility, macro- and micro-structure) were investigated. Results showed that the amylopectin could decrease the apparent viscosity, storage modulus and loss modulus of PPI dispersion. The addition of amylopectin promoted the formation of protein anisotropic structure and improved the fibrous degree of the extrudates. On the other hand, the amylose had no significant effect on the apparent viscosity of PPI dispersion and could not contribute to the protein fibrous structure formation. Furthermore, both the amylose and amylopectin could significantly reduce the die pressure and torque during the high-moisture extrusion processing, which further decreased the color difference (ΔE), hardness, springiness, and chewiness of the extrudates. Overall, it suggested that the amylose/amylopectin mixture with the ratio of 0:1 was advantageous for preparing the pea protein-based meat substitutes with rich fibrous structure.

A new insight into the high-moisture extrusion process of peanut protein: From the aspect of the orders and amount of energy input

Extruder always provides a comprehensive thermomechanical energy input way, which is decisive for the quality of the extrudate. To get a full understanding of the energy input way during high-moisture extrusion process, effects of the orders and amount of energy input (extrusion temperature, moisture content, shear order, and shear strength) on the system response parameters (die pressure, die temperature, and specific mechanical energy (SME)) and the quality (color, fibrous structure, tensile properties, hardness, and springiness) of the extrudate were assessed. Further, interrelationships between system response parameters and quality of the extrudate were analyzed. Results showed that for controlling the die pressure and die temperature, the shear way plays a decisive role, followed by the extrusion temperature, and finally the moisture content. SME is mainly determined by the moisture content and the energy input intensity. Shear way can significantly improve the fibrous structure. Extrusion temperature is the decisive factor in the tensile properties and springiness. While the moisture content plays a more important role in the color values and the hardness. The energy input way has a large impact on the relationship of the system response parameters and properties of the high-moisture texturized peanut protein.

Relative Genetic and Environmental Contributions to Variations in Human Retinal Electrical Responses Quantified in a Twin Study

PurposeTo estimate heritability of parameters of human retinal electrophysiology and to explore which parameters change with age.DesignProspective, classic twin study.ParticipantsAdult monozygotic and dizygotic twin pairs recruited from the TwinsUK cohort.MethodsElectroretinogram responses were recorded using conductive fiber electrodes in response to stimuli incorporating standards set by the International Society for the Clinical Electrophysiology of Vision. These parameters were extracted; in addition, photopic negative-response (PhNR; originating from retinal ganglion cells) and i-wave components were extracted from responses to the photopic single flash. Parameter values were averaged from both eyes.Main Outcome MeasuresMean values were calculated for the cohort. Correlation coefficients with age were calculated (averaging parameters from both twins from each pair). Coefficients of intrapair correlation were calculated for monozygotic and dizygotic twins. Age-adjusted heritability estimates were derived using standard maximum likelihood structural equation twin modeling.ResultsResponses were recorded from 210 participants in total (59 monozygotic and 46 dizygotic twin pairs). Ninety-three percent were women. Mean age for the cohort was 62.4 years (standard deviation, 11.4 years). In general, response amplitudes correlated negatively, and implicit times positively, with age. Correlations were statistically significant (P < 0.05) and moderate or strong (coefficient, >0.35) for the following parameters: scotopic standard and bright-flash a-wave implicit times, photopic 30-Hz flicker and single-flash b-wave implicit times, and PhNR and i-wave implicit times. Intrapair correlations were higher for monozygotic than dizygotic twins, suggesting important genetic influences. Age-adjusted estimates of heritability were significant for all parameters (except scotopic dim-flash b-wave implicit time), ranging from 0.34 to 0.85. Highest estimates were for photopic single-flash a-wave and b-wave amplitudes (0.84 and 0.85, respectively).ConclusionsThis study explored heritability of retinal electrophysiologic parameters and included measurements reflecting ganglion cell function. Most parameters showed significant heritability, indicating that genetic factors are important, determining up to 85% of the variance in some cone system response parameters. Scotopic responses tended to show lower heritability (possibly relating to greater rod system susceptibility to environmental factors). Future studies can explore the identity of these genetic factors, improving our understanding of how they shape retinal function.

Seismic Safety Evaluation of Reinforced Concrete Walls through FEMA P695 Methodology

AbstractQuantification of building system performance and response parameters such as response modification coefficient (R), system overstrength factor (Ω0), and deflection amplification factor (Cd...

Individual macromolecule motion in a crowded living cell.

The application of the general model of the law of mass action itself, of the achievement of dynamic, statistical equilibria, has led to great successes in describing the theory of single-molecule biophysics and biochemistry based on individually and freely diffusing molecules in dilute liquid and crowded living cells. For example, anomalous diffusion is a general phenomenon in living cells. There is solid evidence for analyzing fluorescence correlation and dual color fluorescence crosscorrelation spectroscopy data (FCS and dual color FCCS) in cellular applications by equations based on anomalous subdiffusion. Using equations based on normal diffusion causes artifacts of the fitted biological system response parameters and of the interpretations of the FCS and dual color FCCS data in the crowded environment of living cells. Equations based on normal diffusion are not valid in living cells. The original article embraces the status of the experimental situation and touches obstacles that still hinder the applications of single molecules in the cellular environment.

ICONE23-1054 ROSHNI : A NEW INTEGRATED SEVERE ACCIDENT SIMULATIONS CODE FOR PHWR LEVEL 2 PSA APPLICATIONS AND SEVERE ACCIDENT SIMULATOR DEVELOPMENT

Severe accident progression in a PHWR is strongly influenced by the large variability that exists amongst various fuel channels and fuel entities within channels. A best effort prediction necessitates consideration of all risk sensitive phenomena and processes in a detail that reduces uncertainties in rates as well as magnitudes of source terms. A review of available computational codes points to a need of a much greater than hitherto undertaken, detailed modelling of the horizontal PHWR reactor channels, fuel bundles, end fittings and feeders with an advanced, more reactor geometry specific consideration of solid debris behaviour in the Calandria vessel. A new computer code ROSHNI improves upon existing computational aides firstly in detail in which the reactor is modelled and further in its fuller consideration of important PHWR related severe accident progression pathways and phenomena. The paper details the code modelling approach used in capturing the important system response parameters. It is expected that the source terms of Deuterium gas and fission products can now be evaluated with lesser uncertainty and with greater degree of control available to the analysts. Users are able to perform parametric and uncertainty analyses with greater ease. Initial modelling of progression of a severe core damage accident is being targeted for a CANDU 6 reactor. However, the code structure is generalized to extend the ability to other PHWR designs including multi-unit CANDU stations and Indian PHWRs. After Fukushima, serious concerns have been raised about severe accident mitigation capabilities of all operating nuclear power plants including CANDU reactors whose design concept presents specific vulnerabilities not common with other reactor types. While operating organizations and their supportive regulating bodies are cautious, to the point of lethargy, about design upgrades to operating reactors, only a best effort modelling of realistic accident progression pathways can empower them with the information required to justify the required risk reduction upgrades to reactors that were never designed with severe accidents within their design basis. Reduction of uncertainties by better modelling can also assist in the development of more effective severe accident management options and better operator training as the lessons learnt from Fukushima must be taken seriously. Otherwise decisions on hardware upgrades will remain handicapped by larger than necessary uncertainties inherent in the available but obsolete PHWR reactor severe accident modelling techniques. This paper concentrates on the rationale for development of a new code; its overall modelling approach and details of reactor core modelling. In summary, the code models transient behaviour of each and all fuel channels; models all individual fuel bundles with each represented by 16 fuel and Zircaloy rings; computes the response of the associated end fittings and carbon steel feeders; considers fuel heatup during staggered boiloff in channels followed by differentiated dry heatup of each fuel channel in steam and deuterium with consideration of moderator depletion. In all, fuel temperatures are evaluated at about 80,000 locations with separate consideration of thermal behaviour of 380 pairs of end fittings and the same number of feeders whose thermo-chemical response to severe accident conditions has a potential of generating additional combustible gas, not previously evaluated. It considers disassembly and thermo-chemical behaviour of individual fuel bundles to multiple fields of debris first suspended over underlying intact channels and gradually relocated to the Calandria vessel with consideration of impact of about 100 in-core devices. It also considers effect of failure of the Calandria vessel under thermomechanical loads and evaluates energy and fission product source terms for containment response. Deuterium gas source

In vitro and in vivo studies for assessing the immune response and protection-inducing ability conferred by Fasciola hepatica-derived synthetic peptides containing B- and T-cell epitopes.

Fasciolosis is considered the most widespread trematode disease affecting grazing animals around the world; it is currently recognised by the World Health Organisation as an emergent human pathogen. Triclabendazole is still the most effective drug against this disease; however, resistant strains have appeared and developing an effective vaccine against this disease has increasingly become a priority. Several bioinformatics tools were here used for predicting B- and T-cell epitopes according to the available data for Fasciola hepatica protein amino acid sequences. BALB/c mice were immunised with the synthetic peptides by using the ADAD vaccination system and several immune response parameters were measured (antibody titres, cytokine levels, T-cell populations) to evaluate their ability to elicit an immune response. Based on the immunogenicity results so obtained, seven peptides were selected to assess their protection-inducing ability against experimental infection with F. hepatica metacercariae. Twenty-four B- or T-epitope-containing peptides were predicted and chemically synthesised. Immunisation of mice with peptides so-called B1, B2, B5, B6, T14, T15 and T16 induced high levels of total IgG, IgG1 and IgG2a (p<0.05) and a mixed Th1/Th2/Th17/Treg immune response, according to IFN-γ, IL-4, IL-17 and IL-10 levels, accompanied by increased CD62L+ T-cell populations. A high level of protection was obtained in mice vaccinated with peptides B2, B5, B6 and T15 formulated in the ADAD vaccination system with the AA0029 immunomodulator. The bioinformatics approach used in the present study led to the identification of seven peptides as vaccine candidates against the infection caused by Fasciola hepatica (a liver-fluke trematode). However, vaccine efficacy must be evaluated in other host species, including those having veterinary importance.

Adaptive Neuro-Fuzzy Inference System based speed controller for brushless DC motor

In this paper, a novel controller for brushless DC (BLDC) motor has been presented. The proposed controller is based on Adaptive Neuro-Fuzzy Inference System (ANFIS) and the rigorous analysis through simulation is performed using simulink tool box in MATLAB environment. The performance of the motor with proposed ANFIS controller is analyzed and compared with classical Proportional Integral (PI) controller, Fuzzy Tuned PID controller and Fuzzy Variable Structure controller. The dynamic characteristics of the brushless DC motor is observed and analyzed using the developed MATLAB/simulink model. Control system response parameters such as overshoot, undershoot, rise time, recovery time and steady state error are measured and compared for the above controllers. In order to validate the performance of the proposed controller under realistic working environment, simulation result has been obtained and analyzed for varying load and varying set speed conditions.

On the Extreme Value Analysis of the Response of a Turret Moored FPSO

One of the standardized procedures used in the design of floating systems and their mooring and production lines is the so-called short-term design approach where the system is analyzed for some specific extreme environmental conditions. Along with this procedure, a nonlinear time-domain coupled dynamic analysis, considering the floater and its risers and mooring lines, can nowadays be incorporated as a feasible part of the design practice. One very important and challenging aspect of this process is concerned with the estimation of the characteristic short-term extreme values of the system response parameters based on the sampled time-series. In this paper a common procedure used to establish these extreme values for floater system response parameters, which is based upon a Weibull distribution model for the peaks of the time-series, is reviewed in the light of a recently proposed approach based on a general parametric model for the average conditional exceedance rate of peaks. It is shown that the former model corresponds to a particular case of the latter one. Numerical results are presented for the response parameters of a turret-moored Floating, Production, Storage and Offloading (FPSO) unit considering a short-term coupled analysis of the whole system under an extreme environmental condition of wind, wave, and current. Specifically, the extreme response of surge motion, top tension of the most loaded mooring line, and Det norske Veritas (DnV) codes utilization factor for the most critical section of an 0.20 m outer diameter SLWR (steel lazy wave riser) are investigated.

Evaluation of behavior factor of tunnel‐form concrete building structures using Applied Technology Council 63 methodology

SUMMARYTunnel‐form construction system is used for buildings made up of slabs and walls. This system has represented fast construction technique, low cost and time saving in the construction period. However, there are no special requirements for seismic design of this type of buildings, and some provisions of the concrete bearing wall system are used. None of the seismic codes addresses the R factor for tunnel‐form buildings directly, and some doubts remained about prediction of the fundamental period. Meanwhile the force‐based methods, which depended on R factor and fundamental period, are still used for seismic design of this type of buildings. There is a need for evaluating the R factor for tunnel‐form buildings. The methodology was developed by the Applied Technology Council (ATC) entitled ATC‐63 Project for quantifying building system performance and response parameters for use in seismic design. Here, this methodology is used to estimate more reliable R factor for tunnel‐form buildings. An experimental program was carried out to decrease the uncertainty of finite element modeling and using it as a part of the methodology. A database was created, and some analyses were performed. The results of analysis were summarized to propose more accurate R factor for tunnel‐form buildings. Copyright © 2011 John Wiley &amp; Sons, Ltd.

On the existence of a lactate threshold during incremental exercise: a systems analysis.

The relationship between blood lactate concentration ([La]) and O2 uptake (VO2) during incremental exercise remains controversial: does [La] increase smoothly as a function of VO2 (continuous model), or does it begin to increase abruptly above a particular metabolic rate (threshold model)? The dynamic characteristics of the underlying physiological system are investigated using system identification analysis techniques. A multivariate deterministic time series model of the [La] and VO2 response to incremental changes in work rate was fitted to simulated and experimental data. Time-varying system response parameters were determined through the application of a weighted recursive least squares algorithm. The model, using the identified time-varying parameters, provided a good fit to the data. The variation of these parameters over time was then examined. Two major transitions in the parameters were found to occur at intensity levels equivalent to 53 +/- 8% and 77 +/- 9% maximal VO2 (experimental data). These changes in the model parameters indicate that the best linear dynamic model that fits the observed system behavior has changed. This implies that the system has changed its operation in some way, by altering its structure or by moving to a different operating region. The identified parameter changes over time suggest that the exercise intensity range (from rest to maximal VO2) is divided into three main intensity domains, each with distinct dynamics. Further study of this three-phase system may help in the understanding of the underlying physiological mechanisms that affect the dynamics of [La] and VO2 during exercise.

Interpretation of emission image of an axisymmetric diffusion flame into 2-dimensional temperature data using a simplified computed tomography

Photographic images of axisymmetric diffusion flames were interpreted using the computed tomographic techinque. The two dimensional images of an axisymmetric diffusion flame were measured by a commercial CCD array camera and a frame grabber. The image data were then used to reconstruct the original three dimensional spatially resolved distributions of emission intensities by using the computed tomographic technique. The reconstructed volumetric emission intensities were then converted into optical temperatures of soot particles by assuming that the system response parameters were constant. The constants were determined from the calibration tests with a blackbody cavity, and with thermocouple measurements. The reconstructed temperatures, which were considered as the temperatures of soot particles, showed reasonable resemblance to the expected temperature distribution. The characteristics of the optical system, such as F number and pixel distance (magnification of image), with respect to the accuracy of reconstructed data were discussed.

OPTIMUM STRUCTURAL DESIGN IN RANDOM VIBRATION ENVIRONMENTS

The optimum design problem for structural systems operating in random vibration environments is formulated with constraints on system response parameters such as stresses, acceleration, fatigue damage, system natural frequencies and side constraints on design variables. The problem is reduced to a nonlinear programming problem and solved using the sequential unconstrained minimization technique of Fiacco and McCormick. Three examples are presented to illustrate the feasibility of the proposed formulation. The paper provides an algorithm for automated optimum design of structural systems subjected to random excitation.

On the self contained modelling of DB/DC systems

This paper discusses the modelling of DB/DC systems operating in a demand paging environment. As an extension of an earlier definition of Denning a class of systems is defined, those operating with "working set integrity", for which one can obtain system response parameters solely from the resource requirements of the input processes when running in isolation. No external information such as a miss ratio curve from another systems environment is required. The interdependence between the resource requirements of processes when running in a systems environment and the system performance parameters is faced directly and expressed as a set of simultaneous equations. The emphasis is on the effect of the sharing of a common set of pages among the active set of processes. Both unrestricted shared usage and usage with locking are treated.

Vibration Isolation With Nonlinear Damping

This paper discusses the performance characteristics of single degree-of-freedom vibration isolation systems in which the isolator damping force is proportional to the relative velocity across the isolator raised to an arbitrary power. The concept of equivalent viscous damping is employed to develop a general equation for the equivalent viscous damping ratio which is used to determine approximate isolation system response parameters. A range of isolator damping nonlinearity is studied by varying the relative velocity exponent between 0.5 and 5 for a fixed value of damping. Detailed results for parametric variations in damping are presented for specific values of the relative velocity exponent that correspond to Coulomb, viscous, quadratic, and cubic damping mechanisms.

Algebraic relations between system response and system parameters for linear time-invariant systems

By means of a rational-fraction approximation to the delay function, and through use of a generalised technique for evaluating convolution integrals, it is possible to approximately evaluate the inverse Laplace transform. The time-domain response is approximated by a ratio of polynomials in t, with coefficients which are algebraic functions of the system parameters.

The AN/MSN-3: An Automatic Ground-Controlled Approach System

A system is described whereby information gathered by a standard ground controlled approach (GCA) radar is utilized to compute automatically all GCA approach-control commands; these commands are then transmitted simultaneously to a maximum of six aircraft via the USAF frequency-division digital data link for automatic control of the aircraft approach. The system is designed to enable continuous human monitoring of the AGCA traffic-control operation and to include visual and aural warning signals in the monitoring system for added safety. Problems relating to optimum system response and gain parameters are discussed and control equations are defined. Results of extensive testing demonstrate a system capable of providing smooth control during the aircraft final approach under high-density traffic conditions. System accuracy is well within specified limits of ±50 feet in azimuth and ±30 feet in elevation at a minimum release point 100 feet above the runway.