Multipoint Model Research Articles

Positive Charges on the Surface of Thaumatin Are Crucial for the Multi-Point Interaction with the Sweet Receptor.

Thaumatin, an intensely sweet-tasting protein, elicits sweet taste with a threshold of only 50 nM. Previous studies from our laboratory suggested that the complex model between the T1R2-T1R3 sweet receptor and thaumatin depends critically on the complementarity of electrostatic potentials. In order to further validate this model, we focused on three lysine residues (Lys78, Lys106, and Lys137), which were expected to be part of the interaction sites. Three thaumatin mutants (K78A, K106A, and K137A) were prepared and their threshold values of sweetness were examined. The results showed that the sweetness of K106A was reduced by about three times and those of K78A and K137A were reduced by about five times when compared to wild-type thaumatin. The three-dimensional structures of these mutants were also determined by X-ray crystallographic analyses at atomic resolutions. The overall structures of mutant proteins were similar to that of wild-type but the electrostatic potentials around the mutated sites became more negative. Since the three lysine residues are located in 20–40 Å apart each other on the surface of thaumatin molecule, these results suggest the positive charges on the surface of thaumatin play a crucial role in the interaction with the sweet receptor, and are consistent with a large surface is required for interaction with the sweet receptor, as proposed by the multipoint interaction model named wedge model.

Simulation and Analysis of Multi-point Sound Source Model for Transformer

In order to evaluate the noise radiation level of substation accurately, a proper transformer acoustic model should be established. Multi - point source s equivalent model is an effective acoustic model of transformer, but how to determine the number of equivalent sound sources is always a difficult problem. In this aper, the noise of a substation is tested, and the multi - point acoustic models with different numbers of equivalent sound sources are established by using LMS Virtual . Lab software. The sound field of the transformer are calculated by using the established simulation models and the results at the corresponding field points are compared with the measured data, the reasonable number of equivalent sound source model is determined. It provides a reference to the research of transformer multi - point acoustic source s model.

Toward advanced sodium-ion batteries: a wheel-inspired yolk–shell design for large-volume-change anode materials

The WS structure with a multipoint model succeeds in addressing the sluggish electron/ion transfer at the yolk–shell interface and structural degradation.

Robust feedback-linearization control for axial power distribution in pressurized water reactors during load-following operation

Abstract Improved load-following capability is one of the most important technical tasks of a pressurized water reactor. Controlling the nuclear reactor core during load-following operation leads to some difficulties. These difficulties mainly arise from nuclear reactor core limitations in local power peaking: the core is subjected to sharp and large variation of local power density during transients. Axial offset (AO) is the parameter usually used to represent the core power peaking. One of the important local power peaking components in nuclear reactors is axial power peaking, which continuously changes. The main challenge of nuclear reactor control during load-following operation is to maintain the AO within acceptable limits, at a certain reference target value. This article proposes a new robust approach to AO control of pressurized water reactors during load-following operation. This method uses robust feedback-linearization control based on the multipoint kinetics reactor model (neutronic and thermal-hydraulic). In this model, the reactor core is divided into four nodes along the reactor axis. Simulation results show that this method improves the reactor load-following capability in the presence of parameter uncertainty and disturbances and can use optimum control rod groups to maneuver with variable overlapping.

Robust observer based control for axial offset in pressurized-water nuclear reactors based on the multipoint reactor model using Lyapunov approach

Abstract In nuclear reactor imbalance of axial power distribution induces xenon oscillations. These fluctuations must be maintained bounded within allowable limits. Otherwise, the nuclear power plant could become unstable. Therefore, bounded these oscillations is considered to be a restriction for the load following operation. Also, in order to design the nuclear reactor control systems, poisons concentrations, especially xenon must be accessible. But, physical measurement of these parameters is impossible. In this paper, for the first time, in order to estimate the axial xenon oscillations and ensures these oscillations are kept bounded within allowable limits during load-following operation, a robust observer based nonlinear control based on multipoint kinetics reactor model for pressurized-water nuclear reactors is presented. The reactor core is simulated based on the multi-point nuclear reactor model (neutronic and thermal-hydraulic). Simulation results are presented to demonstrate the effectiveness of the proposed observer based controller for the load-following operation.

Estimation of the poisons reactivity in the P.W.R Nuclear Reactors using modified higher order sliding mode observer based on the multi-point nuclear reactor model

Reactor power control is one of the most important problems in a nuclear power plant. Considering the importance of the negative feedback reactivity from neutron absorber poisons such as xenon and samarium in the design of the nuclear reactor control system and regarding the limitations of the xenon and samarium reactivity measurement, in this paper, for the first time, a modified higher-order sliding mode observer is presented to estimate the xenon and samarium reactivity in the P.W.R Nuclear Reactors. The reactor core is simulated based on the multi-point nuclear reactor model (neutronic and Thermal-hydraulic) and three delayed neutrons groups. Traditional sliding mode technique has intrinsic problem of chattering. To cope with this problem, Higher Order Sliding Mode (HOSM) is used. The employed method is easy to implement in practical applications and moreover, the higher order sliding mode control exhibits the desired dynamic behavior during the entire output-tracking process. Simulation results are presented to demonstrate the effectiveness of the proposed observer in terms of performance, robustness and stability and show that the HOSM observer follows the actual system variables accurately and is satisfactory in the presence of the parameters uncertainties and disturbances.

The core instability analysis under ocean condition for offshore floating nuclear power plant with neutron coupling based on multi-point model

For offshore floating nuclear power system the ocean conditions, such as rolling, must be considered for safe design. The neutron kinetics decides the power distribution and variation. Both of them will change the characteristics of the core instability. In this paper the ocean condition model and multi-point reactor model are added into the parallel channel system thermal-hydraulic model. A reactor core with 121 assemblies based on QinshanII nuclear power plant is selected as research object. The inherent instability of the system is studied firstly as the basis of comparison. Then the instability boundaries under motion condition and neutron feedback are obtained separately. The joint influence of motion and neutron feedback is studied. The results indicate that ocean condition has very limited effect for such system with so many parallel channels. Neutron feedback in different inlet subcooling regions have different influence tendency. The combined effect is very powerful and should be paid more attention. At last part the spectral analysis method is used to discuss the influence of the coupling calculation method.

Performance Improvement of Small Unmanned Aerial Vehicles Through Gust Energy Harvesting

Fixed-wing miniature aerial vehicles usually fly at low altitudes that are often exposed to turbulent environments. Gust soaring is a flight technique of energy harvesting in such a complex and stochastic domain. The presented work shows the feasibility and benefits of exploiting a nonstationary environment for a small unmanned aerial vehicle. A longitudinal dynamics trajectory is derived, showing significant benefits in extended flight with a sinusoidal wind profile. An optimization strategy for active control is performed, with the aim of obtaining the most effective set of gains for energy retrieval. Moreover, a three-dimensional multipoint model confirms the feasibility of energy harvesting in a more complex spatial wind field. The influence of unsteady aerodynamics is determined on the overall energy gain along the flight path with active proportional control. The aerodynamic derivatives describing the contribution to lift by a change in angle of attack and elevator deflection are identified as the most contributing aerodynamic parameters for energy harvesting in a gusty environment, and are therefore suggested as a basic objective function of an unmanned aerial vehicle design for such a flight strategy.

Research on optimal driver steering model based on Multi-Point preview

In this paper, multi-point preview control algorithm is applied to driver steering control model. This paper builds multi-point preview road model in the form of state shift register. Based on the linear quadratic regulator (LQR) optimal control theory it optimizes driver steering control model with multi-point preview. Meanwhile, in the Matlab \\ Simulink environment, based on vehicle system dynamics and optimal control theory, different preview points and weighted coefficients are simulated to study the influence of driver steering model. The simulation results show that the multi-point preview control mode has excellent driving performance. And in this paper, the main parameters affecting the preview control algorithm such as speed, preview weighted coefficients and the number of preview points and so on are discussed.

Adaptive Multipoint Model Order Reduction Scheme for Large-Scale Inductive PEEC Circuits

The model order reduction techniques based on the multipoint projection Krylov methods have become the methods of choice to generate large macromodels of multiport RLC circuits. A well-known difficulty with such methods lies in the need for clever point selection to attain model compactness and accuracy. In this paper, we present an automatic methodology for optimizing sample point selection. This method is general, suitable for circuits obtained by the partial element equivalent circuit method coupled with an adaptive multilevel fast multipole method. Our algorithm has been validated on an industrial example to demonstrate the accuracy and robustness of the approach.

Abstract 4643: Plasma thioredoxin reductase 1 as a diagnostic marker for non-small cell lung cancer

Abstract Non-invasive diagnostic markers for patients with suspicious non-small cell lung cancer (NSCLC) may provide needed guidance on invasive diagnostic and therapeutic decisions. Thioredoxin reductase 1 (TrxR1) is a pivotal intracellular redox sensor and antioxidant enzyme, and plays an important part in tumor growth, progression, metastasis, and chemotherapy resistance. The goal of this study is to test the feasibility of developing plasma TrxR1 as a novel diagnostic marker for NSCLC. The plasma TrxR1 activity was determined spectrophotometrically by monitoring the NADPH-dependent production of 2-nitro-5-thiobenzoate at 412nm and at 37°C. All detection kits and automatic analyzer possess independent intellectual property rights, and have been widely used in breast cancer screening. In this study, the plasma levels of TrxR1 were measured in 45 treatment-naïve NSCLC patients and 10 individuals with benign tumor-like pulmonary diseases. Taking plasma TrxR1 activity of 4 as reference, the overall concordance rate was 73.3%, while those of CEA, CA199, CA125, NSE, CYFRA21-1 and SCC were 19.0%, 7.1%, 16.7%, 35.7%, 24.4% and 2.5%, respectively. Furthermore, using TNM staging (AJCC 7th ed.) as classifier, the concordance rates of TrxR1 in local, local regional and advanced stage subgroups were 66.7% (20/30), 77.8% (7/9) and 100% (4/4), respectively. A multipoint linear fitting correlation model was created, and the equation was TrxR1 = 5.821 + 0.396*Stage. Besides, the concordance rates of TrxR1 in benign tumor-like pulmonary diseases was 60% (6/10). Our data suggest that plasma TrxR1 activity is a useful non-invasive diagnostic marker for NSCLC, and there may be a linear correlation between TrxR1 activity and pathological stage. Citation Format: Xiaozheng Kang, Chaoran Dong, Bocun Shen, Wanpu Yan, Liang Dai, Yongbo Yang, Hanwei Yin, Guobing Xu, Huihui Zeng, Ke-Neng Chen. Plasma thioredoxin reductase 1 as a diagnostic marker for non-small cell lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4643. doi:10.1158/1538-7445.AM2017-4643

An Economic Multipoint Gravitational Model Expression Of A Transactional Analysis Game: An Application To Recreational Private Land Use Decisions

The outcome of interactions between various economic actors has a decided subconscious component. Transactional analysis (TA), which was developed in the late 1950s, provides a cognitive theory about the way that human beings interact with each other on a subconscious level that can be applied to investigation of economic decision making. TA, founded by physician Eric Berne, explains a number of potential human interactions, or social transactions, by framing them as subconscious games. Individual economic actors in markets interact with each other. Those interactions may be influenced at least somewhat by subconscious cognitive processes and TA games. Additionally, because individuals gain experience through each interaction, there may reasonably be expected to exist an historical component in which the subconscious response of economic actors to others in the market and to the subconscious games of others in the market may change over time based on their experiences in prior games. As an extension, an individual’s subconscious response to other economic actors may in part be based on the influence of information, either conveyed through games or via other sources. This study investigates decision strategy in the context of marketplace interaction in which outcomes are influenced by subconscious social transaction games played between individuals. The decision by land owners of whether or not to open private land to outside parties for recreational use is considered as an example. Because interaction necessarily involves some form of influence, the interaction and decision strategy are modeled mathematically by an economic multipoint gravitational model in which each actor both influences all other actors and is influenced by them.

Serum thioredoxin reductase 1 as a diagnostic marker for non-small cell lung cancer.

e23069 Background: Non-invasive diagnostic markers for patients with suspicious non-small cell lung cancer (NSCLC) may provide needed guidance on invasive diagnostic and therapeutic decisions. Thioredoxin reductase 1 (TrxR1) is a pivotal intracellular redox sensor and antioxidant enzyme, and plays an important part in tumor growth, progression, metastasis, and chemotherapy resistance. The goal of this study is to test the feasibility of developing plasma TrxR1 as a novel diagnostic marker for NSCLC. Methods: The plasma TrxR1 activity was determined spectrophotometrically by monitoring the NADPH-dependent production of 2-nitro-5-thiobenzoate at 412nm and at 37℃. All detection kits and automatic analyzer possess independent intellectual property rights, and have been widely used in breast cancer screening. Results: In this study, the plasma levels of TrxR1 were measured in 109 treatment-naïve resectable NSCLC patients and 15 individuals with benign tumor-like pulmonary diseases. Taking plasma TrxR1 activity of 5.0 as reference, the overall concordance rate was 58.1%, while those of CEA, CA199, CA125, NSE, CYFRA21-1 and SCC were 19.2%, 8.2%, 2.1%, 45.9%, 25.3% and 9.5%, respectively. Furthermore, using TNM staging (AJCC 7th ed.) as classifier, the concordance rates of TrxR1 in benign tumor-like pulmonary diseases, local and regional stage NSCLC subgroups were 53.3% (8/15), 57.5% (46/80) and 63.0% (17/27), respectively. A multipoint linear fitting correlation model was created, and the equation was TrxR1 = 5.716 + 0.4898*Stage. Conclusions: Our data suggest that plasma TrxR1 activity is a useful non-invasive diagnostic marker for NSCLC, and there may be a linear correlation between TrxR1 activity and pathological stage.

Estimation of axial xenon oscillations with online parameter adaptation in the P.W.R nuclear reactors using Lyapunov approach based on the multipoint kinetics reactor model

In nuclear power plants, imbalance of axial power distribution induces xenon oscillations. These oscillations must be maintained within acceptable limits; otherwise, the nuclear power plant could become unstable. Therefore, axial xenon oscillations must be considered during the load-following operation. Besides, xenon concentration and axial xenon oscillations are not measurable in practice; therefore, they should be estimated using suitable observer. In this paper, in order to estimate the axial xenon oscillations for the load-following operation, an adaptive estimator is presented based on the multipoint kinetics reactor model. Besides, regarding the limitations of the xenon concentration and delayed neutron precursors densities measurement to design the nuclear reactor control systems, the presented observer can estimate their values, carefully. The adaptation laws for updating the reactor parameters are generated using the Lyapunov approach. In the proposed adaptive estimator, both parameters and state variables of the nuclear reactor are estimated simultaneously. Also, the stability analysis is given by means of Lyapunov approach, thus the system is guaranteed to be stable within a large range. Simulation results are presented to demonstrate the effectiveness of the proposed observer in terms of performance, robustness and stability and show that the adaptive estimator follows the actual system variables and parameters accurately and are satisfactory in the presence of the parameters uncertainties and disturbances.

A Simple Tetraminocalix[4]arene as a Highly Efficient Catalyst under "On-Water" Conditions through Hydrophobic Amplification of Weak Hydrogen Bonds.

The simple tetraminocalix[4]arene 1, which contains weak H-bond-donor NH2 groups, is reported to be a highly efficient organocatalyst for the Vinylogous Mukaiyama Aldol Reaction (VMAR) of 2-(trimethylsilyloxy)furan 5 with α-ketoesters 6 a-l under "on-water" conditions owing to the hydrophobic amplification of weak H-bond interactions. The catalytic efficiency of calixarene catalyst 1 was shown to be closely related to its recognition abilities towards the reactants 5 and 6 through a multipoint recognition model. The proposed model provided good explanations for the differences on the reaction rate acceleration and on the stereoselectivity observed with different substrates.

A multi-point parameterized model reduction for large parametric systems by using Krylov-subspace techniques

This paper presents a multi-point parameterized model reduction method based on Krylov-subspace techniques for large parametric systems where the parametric dependence in system matrices can be nonaffine and the parameters are in a wide range. First, a large parametric system is approximated as a weighted combination of different linear parametric systems, which are obtained by Taylor expansion on the different selected parameter expansion points. Then, a numerically stable algorithm based on self-moments and cross-moments is proposed to obtain a reduced parametric system with high fidelity in the full ranges of the parameters. The accuracy of the obtained reduced parametric systems can be improved by applying the multi-point expansions and weighted functions proposed in this paper. Two benchmarks in practical applications are assessed by employing different parameterized model reduction methods. The numerical simulation results verify the effectiveness of the proposed method.

Adaptive robust control for axial offset in the P.W.R nuclear reactors based on the multipoint reactor model during load-following operation

Control of the nuclear reactors during load-following operation is the most important problem in nuclear power plants due to safety reasons. In the nuclear reactor, imbalance of axial power distribution induces xenon oscillations. These fluctuations must be maintained bounded within allowable limits. Otherwise, the nuclear power plant could become unstable. Therefore, bounded these oscillations is considered to be a restriction for the load following operation. In this paper, for the first time, in order to ensure these oscillations are kept bounded within allowable limits during load-following operation, an adaptive robust control based on the multipoint kinetics reactor model is presented for P.W.R nuclear reactors. The reactor core is simulated based on the multi-point nuclear reactor model (neutronic and thermal-hydraulic) and three delayed neutrons groups. The adaptation laws for updating the reactor parameters are generated using the Lyapunov approach. The stability analysis is given by means Lyapunov approach, then the control system is guaranteed to be stable within a large range.Simulation results are presented to demonstrate the effectiveness of the proposed adaptive control in terms of performance, robustness and stability and show that the adaptive parameters are bounded and stable in the presence of the parameters uncertainties and disturbances.

Multipoint contact modeling of nanoparticle manipulation on rough surface

In this paper, the atomic force microscopy (AFM)-based 2-D pushing of nano/microparticles investigated on rough substrate by assuming a multipoint contact model. First, a new contact model was extracted and presented based on the geometrical profiles of Rumpf, Rabinovich and George models and the contact mechanics theories of JKR and Schwartz, to model the adhesion forces and the deformations in the multipoint contact of rough surfaces. The geometry of a rough surface was defined by two main parameters of asperity height (size of roughness) and asperity wavelength (compactness of asperities distribution). Then, the dynamic behaviors of nano/microparticles with radiuses in range of 50–500 nm studied during their pushing on rough substrate with a hexagonal or square arrangement of asperities. Dynamic behavior of particles were simulated and compared by assuming multipoint and single-point contact schemes. The simulation results show that the assumption of multipoint contact has a considerable influence on determining the critical manipulation force. Additionally, the assumption of smooth surfaces or single-point contact leads to large error in the obtained results. According to the results of previous research, it anticipated that a particles with the radius less than about 550 nm start to slide on smooth substrate; but by using multipoint contact model, the predicted behavior changed, and particles with radii of smaller than 400 nm begin to slide on rough substrate for different height of asperities, at first.

Trustworthy data delivery in mobile P2P network

Trustworthy, efficient and low-latency communications are arguably the most crucial factors in mobile Peer-to-Peer (P2P) network. In this paper, we present trustworthy multi-point relays data dissemination model for mobile objects in wireless ad-hoc environments. The proposed data delivery model is designed to work in conjunction with our SeCuRE trustworthy scheme and mobile scheduling techniques, forming a novel integrated framework to disseminate messages amongst mobile peers. We evaluate the proposed framework on a number of key metrics for mobile environment, including; transmission cost, computational cost, latency and message deliverability performance. The results of our experiments are used to make comparisons with current state-of-the-art techniques, namely; pure flooding and Trustworthiness-based Broadcast (TBB) scheme, from which the effectiveness of our proposed approach is identified.

A Multi-Point Tire Model for Studying Bridge–Vehicle Coupled Vibration

The contact between a vehicle tire and the road surface has been usually assumed as a single-point contact in the numerical simulation of vehicle–bridge interacted vibrations. In reality, the tire contacts the road surface through a patch instead of a single point. According to some recent studies, the single-point tire model may overestimate the dynamic amplification of bridge responses due to vehicle loadings. A new tire model, namely, the multi-point tire model, is therefore proposed in this paper with the purpose of improving the accuracy of numerical simulation results over the single-point model, while maintaining a certain level of simplicity for applications. A series of numerical simulations are carried out to compare the effect of the proposed tire model with those of the existing single-point model and disk model on the bridge dynamic responses. The proposed tire model is also verified against the field test results. The results show that the proposed multi-point tire model can predict the bridge dynamic responses with better accuracy than the single-point model, especially under distressed bridge deck conditions, and is computationally more efficient and simpler for application than the disk model.