scholarly journals Dynamics Analysis and Prediction of Genetic Regulation in Glycerol Metabolic Network via Structural Kinetic Modelling

2015 ◽  
Vol 2015 ◽  
pp. 1-9
Author(s):  
Jianxiong Ye ◽  
Honglei Xu ◽  
Xueying Huang ◽  
Chongrong Ke ◽  
Enmin Feng
Keyword(s):  
Klebsiella Pneumoniae ◽  
Dynamic System ◽  
Genetic Manipulation ◽  
Kinetic Modelling ◽  
Formation Rate ◽  
Genetic Regulation ◽  
Stable State ◽  
Intermediary Metabolite ◽  
The Stability ◽  
Nonlinear Regulation

Glycerol can be biologically converted to 1,3-propanediol (1,3-PD) byKlebsiella pneumoniae. In the synthesis pathway of 1,3-PD, the accumulation of an intermediary metabolite 3-hydroxypropionaldehyde (3-HPA) would cause an irreversible cessation of the dynamic system. Genetic manipulation on the key enzymes which control the formation rate and consumption rate of 3-HPA would decrease the accumulation of 3-HPA, resulting in nonlinear regulation on the dynamic system. The interest of this work is to focus on analyzing the influence of 3-HPA inhibition on the stability of the dynamic system. Due to the lack of intracellular knowledge, structural kinetic modelling is applied. On the basis of statistical account of the dynamical capabilities of the system in the parameter space, we conclude that, under weak or no inhibition to the reaction of 3-HPA consumption, the system is much easier to obtain a stable state, whereas strong inhibition to its formation is in favor of stabilizing the system. In addition, the existence of Hopf bifurcation in this system is also verified. The obtained results are helpful for deeply understanding the metabolic and genetic regulations of glycerol fermentation byKlebsiella pneumoniae.

LANDSLIDE RISK MANAGEMENT IN THE COASTAL ZONE OF THE KUIBYSHEV RESERVOIR DUE THE DESIGN OF HIGH-SPEED LINE "MOSCOW-KAZAN"

2017 ◽  
Author(s):  
Nikolai Petrov ◽  
Nikolai Petrov ◽  
Inna Nikonorova ◽  
Inna Nikonorova ◽  
Vladimir Mashin ◽  
...  
Keyword(s):  
High Speed ◽  
Computational Models ◽  
Stable State ◽  
Landslide Risk ◽  
Kuibyshev Reservoir ◽  
Stepped Surface ◽  
The Stability ◽  
Landslide Slope ◽  
The Village

High-speed railway "Moscow-Kazan" by the draft crosses the Volga (Kuibyshev reservoir) in Chuvashia region 500 m below the village of New Kushnikovo. The crossing plot is a right-bank landslide slope with a stepped surface. Its height is 80 m; the slope steepness -15-16o. The authors should assess the risk of landslides and recommend anti-landslide measures to ensure the safety of the future bridge. For this landslide factors have been analyzed, slope stability assessment has been performed and recommendations have been suggested. The role of the following factors have been analyzed: 1) hydrologic - erosion and abrasion reservoir and runoff role; 2) lithologyc (the presence of Urzhum and Northern Dvina horizons of plastically deformable rocks, displacement areas); 3) hydrogeological (the role of perched, ground and interstratal water); 4) geomorphological (presence of the elemental composition of sliding systems and their structure in the relief); 5) exogeodynamic (cycles and stages of landslide systems development, mechanisms and relationship between landslide tiers of different generations and blocks contained in tiers). As a result 6-7 computational models at each of the three engineering-geological sections were made. The stability was evaluated by the method “of the leaning slope”. It is proved that the slope is in a very stable state and requires the following measures: 1) unloading (truncation) of active heads blocks of landslide tiers) and the edge of the plateau, 2) regulation of the surface and groundwater flow, 3) concrete dam, if necessary.

scholarly journals Study on instability failure mode and monitoring early warning standard of surrounding rock in fully weathered argillaceous sandstone section of large section tunnel

2019 ◽  
Vol 136 ◽  
pp. 04023
Author(s):  
Ming Zhao ◽  
Ke Li ◽  
Hong Yan Guo ◽  
KaiCheng Hua
Keyword(s):  
Limit State ◽  
Stable State ◽  
Simulation Software ◽  
Surrounding Rock ◽  
Large Section ◽  
Rock Stability ◽  
Geological Conditions ◽  
Construction Step ◽  
The Face ◽  
The Stability

Based on the special geological conditions of a tunnel in Qingyuan section of Huizhou-Zhanzhou Expressway, FLAC3d numerical simulation software is used to simulate the rheological properties and instability of surrounding rock in large-section fully weathered sandstone section, and the stability and loss of surrounding rock are analyzed. The deformation of the dome and the face at steady state is analyzed. It is found that: 1) when the surrounding rock is in a stable state, the deformation curve of the dome is smooth. When the surrounding rock of the face is unstable, the front of the face appears ahead. Deformation should be first strengthened on the surrounding rock in front of the face. 2) The arched foot is an important part of the instability of the surrounding rock. In order to prevent the expansion of the collapsed part, the arched part should be reinforced. 3) In order to obtain the limit state of surrounding rock stability, the strength of surrounding rock is reduced, and the strength reduction coefficient corresponding to the displacement sudden point is taken as the safety factor of rock stability around the hole, and the stability safety coefficients of surrounding rock of each construction step are greater than 1.2. 4) The dynamic standard values of deformation control in the whole construction stage are obtained by analyzing the deformation curves of each data monitoring point with time in the corresponding time period of each construction step.

Improved Dynamic System of Microbial Continuous Fermentation and its Parameter Identification

2014 ◽  
Vol 633-634 ◽  
pp. 545-549
Author(s):  
Hong Li Xiao ◽  
Lan Zhang Chong ◽  
Fei Li Hang ◽  
Wang Yong
Keyword(s):  
Dynamic System ◽  
Consumption Rate ◽  
Continuous Fermentation ◽  
Formation Rate ◽  
Product Formation ◽  
Cellular Growth ◽  
Specific Substrate ◽  
Substrate Consumption ◽  
Specific Product ◽  
Product Formation Rate

In this paper, the nonlinear dynamic system of microbe continuous fermentation products 1,3-propanediol (1,3-PD) is rewritten by improving the specific cellular growth rate, specific substrate consumption rate and specific product formation rate. Firstly, under the condition of substrate glycol excess and active trans-membrane transport, according to the dynamic behavior the fermentation process, we consider the glycerol and 1,3–PD concentration within the cell, and improve the specific cellular growth rate, specific substrate consumption rate and specific product formation rate, then rewrite the dynamic system of microbial continuous fermentation process. Secondly, taking the dynamic system as main constraint condition, we establish the parameter identification model and prove the existence of the optimal solution. Lastly, the numerical results calculated by particle swarm algorithm show that the improved model is suitable for describe the dynamic behavior of 1,3-PD, but is not accurate enough for by-products.

scholarly journals On Cauchy’s Interlacing Theorem and the Stability of a Class of Linear Discrete Aggregation Models Under Eventual Linear Output Feedback Controls

Symmetry ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 712 ◽  
Author(s):  
Manuel De la Sen
Keyword(s):  
Dynamic System ◽  
Output Feedback ◽  
Iteration Step ◽  
Stability And Convergence ◽  
Feedback Controls ◽  
Time Aggregation ◽  
The Stability ◽  
The Given ◽  
Stability Results

This paper links the celebrated Cauchy’s interlacing theorem of eigenvalues for partitioned updated sequences of Hermitian matrices with stability and convergence problems and results of related sequences of matrices. The results are also applied to sequences of factorizations of semidefinite matrices with their complex conjugates ones to obtain sufficiency-type stability results for the factors in those factorizations. Some extensions are given for parallel characterizations of convergent sequences of matrices. In both cases, the updated information has a Hermitian structure, in particular, a symmetric structure occurs if the involved vector and matrices are complex. These results rely on the relation of stable matrices and convergent matrices (those ones being intuitively stable in a discrete context). An epidemic model involving a clustering structure is discussed in light of the given results. Finally, an application is given for a discrete-time aggregation dynamic system where an aggregated subsystem is incorporated into the whole system at each iteration step. The whole aggregation system and the sequence of aggregated subsystems are assumed to be controlled via linear-output feedback. The characterization of the aggregation dynamic system linked to the updating dynamics through the iteration procedure implies that such a system is, generally, time-varying.

Comparison of Piezoelectric Structural Damping Based on Velocity Controlled Switching and Pulse Width Modulation Switching Circuits

2012 ◽  
Author(s):  
Dejan Vasic ◽  
Yuan-Ping Liu ◽  
François Costa
Keyword(s):  
Pulse Width Modulation ◽  
Stable State ◽  
Piezoelectric Element ◽  
Voltage Source ◽  
Vibration Velocity ◽  
Constant Voltage ◽  
Vibration Displacement ◽  
Controlled Switching ◽  
The Stability ◽  
Piezoelectric Voltage

Two novel piezoelectric damping techniques (VSD and PWMD) are compared in this paper to the traditional resonant shunt damping technique and SSDV technique. In VSD, the switching shunt circuit turns ON or OFF according to the polarity of the vibration velocity of the host structure to shift the piezoelectric voltage phase. An external voltage source is connected to enlarge the voltage amplitude across the piezoelectric element and to optimize the dissipated power. The PWM shunt technique not only can decrease the audible noises more efficiently but also ensure the stability of the control system with a constant voltage source. The theoretical and the experimental results show that the piezoelectric voltage can be adaptive to the vibration displacement by the pulse widths variation, so the PWMD can stay in stable state with a constant voltage source and can still provide a very good performance.

scholarly journals Deep Bottom Mixed Layer Drives Intrinsic Variability of the Antarctic Slope Front

2019 ◽  
Vol 49 (12) ◽  
pp. 3163-3177 ◽  
Author(s):  
Wilma Gertrud Charlotte Huneke ◽  
Andreas Klocker ◽  
Benjamin Keith Galton-Fenzi
Keyword(s):  
Continental Shelf ◽  
Mixed Layer ◽  
Process Model ◽  
Formation Rate ◽  
Ekman Transport ◽  
Intrinsic Variability ◽  
Subsequent Increase ◽  
The Stability ◽  
Basal Melting ◽  
The Antarctic

AbstractThe Antarctic Slope Front (ASF) is located along much of the Antarctic continental shelf break and helps to maintain a barrier to the movement of Circumpolar Deep Water (CDW) onto the continental shelf. The stability of the ASF has a major control on cross-shelf heat transport and ocean-driven basal melting of Antarctic ice shelves. Here, the ASF dynamics are investigated for continental shelves with weak dense shelf water (DSW) formation, which are thought to have a stable ASF, common for regions in East Antarctica. Using an ocean process model, this study demonstrates how offshore bottom Ekman transport of shelf waters leads to the development of a deep bottom mixed layer at the lower continental slope, and subsequently determines an intrinsic variability of the ASF. The ASF variability is characterized by instability events that affect the entire water column and occur every 5–10 years and last for approximately half a year. During these instability events, the cross-shelf density gradient weakens and CDW moves closer to the continent. Stronger winds increase the formation rate of the bottom mixed layer, which causes a subsequent increase of instability events. If the observed freshening trend of continental shelf waters leads to weaker DSW formation, more regions might be vulnerable for the ASF variability to develop in the future.

Comparison of the effect of poly(N-vinyl caprolactam) and poly(N-isopropyl acrylamide) trimers on the stability of hydrated Na-montmorillonite: A molecular dynamics study

2020 ◽  
pp. 096739112093524
Author(s):  
Jiafang Xu ◽  
Moussa Camara ◽  
Hualin Liao ◽  
Hong Guo ◽  
Kouassi Louis Kra ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Conformational Changes ◽  
Stable State ◽  
Dynamics Simulation ◽  
Effect Of Temperature ◽  
Radius Of Gyration ◽  
Molecular Arrangement ◽  
Isopropyl Acrylamide ◽  
The Stability ◽  
The Impact

In the present study, we performed a molecular dynamics simulation of the intercalation of poly( N-isopropyl acrylamide) (NIPAM)3 and poly( N-vinyl caprolactam) (NVCL)3 trimers into Na-montmorillonite (Na-Mt) to evaluate their effects on the interlayer structure and the stability of hydrated Na-Mt. The impact of both trimers on the interlayer species and their dynamics properties at different temperatures in a canonical ensemble (NVT) were investigated. The results showed that the electrostatic forces exerted by Na cations on H2O molecules and the interlayer H2O molecular arrangement are not affected by the rise in temperature after adding both trimers. Trimer addition reinforced the structure of interlayer H2O molecules so that the effect of temperature increase on them became negligible. The structural dynamics evolution of the radius of gyration of both trimers showed the existence of conformation changes when temperature increased. These conformational changes are more complex in the case of (NVCL)3 than (NIPAM)3 due to its large monomers. Both trimers reduced the mobility of interlayer particles with a better inhibition effect obtained for (NVCL)3 compared to (NIPAM)3. The concentration profile of interlayers’ species showed the affinity of Na cations for clay mineral surfaces while H2O molecules moved away. Compared these two trimers, the most stable state of Na-Mt is achieved with (NVCL)3. These results could help highlight the inhibition properties of (NIPAM)3 and (NVCL)3 on hydrated Na-Mt and to predict its stability against changes in environmental conditions.

A Novel Deployable Hexahedron Mobile Mechanism Constructed by Only Prismatic Joints

2013 ◽  
Vol 5 (4) ◽  
Author(s):  
Wan Ding ◽  
Yan-an Yao
Keyword(s):  
Control Strategy ◽  
Stable State ◽  
Necessary Condition ◽  
Pneumatic Cylinder ◽  
Symmetrical Structure ◽  
System A ◽  
Prismatic Joints ◽  
Binary Control ◽  
The Stability ◽  
Pneumatic Cylinders

This paper proposes a novel deployable hexahedron mobile mechanism that is rigidly linked by only prismatic joints. The mechanism that is a completely symmetrical structure can always keep the walking capability when any of its six faces of the hexahedron touches the ground. It can roll at any stable state. The configuration constructed by only prismatic joints makes it expand and contract as a deployable structure. In this paper, a method for constructing a deployable hexahedron mobile mechanism is proposed. The stability analysis and dynamic simulation of the walking and rolling are carried out. The necessary condition of tipping motion and the speed analysis of two different rolling gaits are studied in details. A binary control strategy is adopted to simplify the complexity of the control system. A pneumatic cylinder is chosen to be the binary actuator. A prototype composed of 180 pneumatic cylinders was fabricated. The validity of the walking and tipping functions are verified by the experimental results.

Vibration Suppression of an Underactuated Dynamic System Using Virtual Actuators

2016 ◽  
Vol 138 (6) ◽  
Author(s):  
A. M. Khoshnood ◽  
I. Azad ◽  
S. M. Hasani
Keyword(s):  
Control System ◽  
Dynamic System ◽  
Attitude Control ◽  
Vibration Suppression ◽  
Nonlinear Dynamic Model ◽  
Attitude Control System ◽  
Suppression Technique ◽  
A New Technique ◽  
And Performance ◽  
The Stability

Sloshing is one of the critical problems in aerospace vehicles with liquid containers. Motion of the liquid in resonance situations can degrade the stability and performance of attitude control systems. Two important characteristics of this time varying phenomenon are sensorless and underactuated properties which lead to difficulty of attitude control system design. In this paper, a new technique based on soft sensor and virtual actuator is used to suppress the effects of fuel sloshing in an aerospace launch vehicle (ALV). For this purpose, a nonlinear dynamic model of the vehicle with mechanical model of the fuel sloshing is considered as a multibody dynamic system. The preliminary attitude control system of the vehicle is extended using the new vibration suppression technique and a numerical simulation of the nonlinear model is carried out. Results of the simulation show that the undesired effects of the fuel sloshing are effectively decreased using the proposed vibration suppression technique.

scholarly journals Pacemaker Created in Human Ventricle by Depressing Inward-Rectifier K+Current: A Simulation Study

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Yue Zhang ◽  
Kuanquan Wang ◽  
Qince Li ◽  
Henggui Zhang
Keyword(s):  
Spatial Distribution ◽  
Ventricular Myocytes ◽  
Stable State ◽  
Inward Rectifier ◽  
Cardiac Conduction ◽  
Pacemaker Activity ◽  
Battery Life ◽  
Conduction Disorders ◽  
Slow Heart Rate ◽  
The Stability

Cardiac conduction disorders are common diseases which cause slow heart rate and syncope. The best way to treat these diseases by now is to implant electronic pacemakers, which, yet, have many disadvantages, such as the limited battery life and infection. Biopacemaker has been expected to replace the electronic devices. Automatic ventricular myocytes (VMs) could show pacemaker activity, which was induced by depressing inward-rectifier K+current (IK1). In this study, a 2D model of human biopacemaker was created from the ventricular endocardial myocytes. We examined the stability of the created biopacemaker and investigated its driving capability by finding the suitable size and spatial distribution of the pacemaker for robust pacing and driving the surrounding quiescent cardiomyocytes. Our results suggest that the rhythm of the pacemaker is similar to that of the single cell at final stable state. The driving force of the biopacemaker is closely related to the pattern of spatial distribution of the pacemaker.

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