Comparative Dynamic Analysis Research Articles

«5+1» COOPERATION FORMATS IN THE CENTRAL ASIAN REGION: ANALYSIS OF ECONOMIC INTERACTION WITH JAPAN

The article analyzes Japan’s economic interaction with Central Asia within the framework of the «5+1» format, which is a unique mechanism of multilateral cooperation that has attracted the attention of leading world powers in recent years due to the strategic importance of the region in the context of energy resources and transit routes. The research is based on a comprehensive analysis of investment, trade and economic relations between the countries of Central Asia and Japan. The main purpose was to identify key trends and factors that determine the dynamics of economic interaction and analyze the interrelations of economies. The hypotheses were tested using comparative statistics, dynamic analysis and graphical method, as well as using statistical methods, including calculation of correlation coefficients and multiple regression. Limitations of the study include the lack of data for some countries and periods. The analysis showed a moderate positive correlation between the GDP (Gross domestic product) of the countries of Central Asia and Japan, indicating economic interdependence. Japan’s investment activity is manifested in significant investments in Kazakhstan and Kyrgyzstan, with recent growth in Tajikistan. Trade turnover between the countries fluctuates due to global and regional factors. Despite the positive correlation of economies, Central Asia's influence on Japan remains limited. Japanese investment plays a key role in the region's development, but political instability and domestic problems in the countries reduce their effectiveness. Trade also faces challenges, including customs barriers and infrastructure limitations.

Comparative dynamic analysis for a ventilated brake disk

Abstract The paper presents a comprehensive dynamic analysis of the ventilated brake disc that fitted on the braking system of a car. There were taken into account several variants of material for the brake disc, determining the own modes of vibrations and also there was performed a frequency response calculation that allows us to estimate the dynamic behavior of the constructive variants, with direct influences on the noises and vibration (NVH). The analysis of the frequency response consists in the validation of the structures in relation to a vibration level in order not to ensure that the frequency response is not too high during a forced stress. Thus was calculated the inertia that characterizes the dynamic rigidity of the analyzed models at certain points, according to the specified directions. The finite element method was used as the calculation method, and CATIA V5 was used as the application, both for modeling and analysis. The CATIA application is an easy environment and already familiar to designers, so it can be used successfully in making preliminary calculations on estimating dynamic behavior in some models used in new projects.

Innovative protection schemes through hardware-in-the-loop dynamic testing.

In microgrid environments, the behaviour of Distributed Generation (DG) during fault conditions varies significantly based on DG types and penetration levels. Conventional Overcurrent Relays (OCRs) with standard time-current characteristics may exhibit limitations during excessive fault scenarios, leading to OCR operating delays and mis-coordination within the microgrid. This study proposes a novel constraint on the maximum Current Multiplier Setting (CMS) and utilizes Water Cycle Algorithm (WCA) and Particle Swarm Optimization (PSO) techniques to optimize the Time Multiplier Setting (TMS). Comparative dynamic analysis through real-time validation shows that the non-standard OCR approach outperforms the standard IEC scheme across all grid operation modes with different type, size and location of DGs. For instance, under F1 conditions, the tripping time of OCR1 was reduced from 0.0226 seconds (IEC) to 0.000981 seconds (non-standard). HIL results further affirm the efficacy of the proposed scheme. The optimization process, implemented in MATLAB and validated using ATP/EMTP simulations and SIPROTEC 7SJ62 relays, demonstrates enhanced microgrid protection coordination, improving system reliability and performance.

Comprehensive rheological and mechanistic evaluation of an asphalt binder and mixture modified with warm mix additives.

Though warm mix asphalt (WMA) technology has been introduced for a long time, there is still reluctance in the industry to utilize it in practice. In regions like India, where WMA incorporation into road construction has been limited over the past two decades, building confidence in local binders is imperative for widespread adoption. Thus, the present study appraises the effect of three commonly used WMA additives in India, namely Sasobit®, Evotherm®, and Zycotherm®, with base binder VG-30 on the rheological and mixture performance parameters. Three dosages of each WMA additive were blended with the control binder to give ten binder combinations. Different binder evaluations such as Superpave grading and parameters, frequency sweep testing, multiple stress creep recovery test, and linear amplitude sweep test were conducted for comparative dynamic mechanical analysis. Based on the binder testing results, suitable dosages of WMA additives were established, and mixture testing was carried out using these specific additive dosages. Binder evaluations showed improvement in high-temperature characteristics with Sasobit® and better fatigue performance with Evotherm®, while Zycotherm® did not alter binder properties significantly. The asphalt mixture testing results indicated satisfactory performance with the three additives based on Marshall stability and flow testing. The WMA additives also showed enhancement in moisture susceptibility based on the modified Lottman test with Zycotherm® demonstrating the best performance. Overall, the study underscores promising effects of the three WMA additives across different parameters, signaling their potential for widespread application in real-world scenarios.

Numerical Modeling and Dynamic Response Analysis of an End-Anchored Floating Bridge With a Damaged Pontoon Under Repair Operation

Abstract Floating bridges face potential hazards due to ship collisions throughout their operational lifetime. In a situation where a pontoon is significantly damaged from an accident, a floating drydock may be used to compensate for the lost buoyancy and provide a dry atmosphere for operations. As the repair might take months, a primary concern is whether the repair can be in-site conducted without shutting down the road traffic. This study aims to investigate the feasibility of using a drydock for the repair. The numerical model of the in-operation damaged bridge is established for a comparative dynamic analysis with the intact end-anchored bridge. Eigenvalue analysis is conducted, and pendulum modes of oscillation are found with an eigen-period of around 15 s. The dynamic responses are analyzed through a series of fully coupled time-domain simulations under various environmental conditions. The results indicate that the standard deviation of the moment about the girder weak axis increases significantly at the damaged pontoon axis due to the excitation of low-frequency resonant response. Swell wave loads might induce dynamic amplification to the damaged bridge, even with a relatively small wave height. In addition, the internal stress of the bridge girder is investigated and found to be larger, especially, at the lower locations of the cross section. It is suggested that the responses can be managed by limiting the excitation of pendulum modes or providing special damping devices in practical engineering.

Effects of innovative reinforced concrete slit shaft configuration on seismic performance of elevated water tanks.

Elevated water tanks are considered crucial infrastructure due to their significant role in supporting essential services. A strong ground motion may result in a failure or significant damage to a reinforced concrete shaft of an elevated water tank because hysteric energy dissipation is limited to the formation of plastic hinges at the base of the shaft, while the nonlinear properties of the rest of the shaft remain underutilised. The innovative system of assembling RC shafts for elevated water tanks using a slit wall technique was developed to enhance energy dissipation along with the shaft height by introducing slit zones. The comparative nonlinear dynamic analysis between three-dimensional models of elevated water tanks with different shaft diameters and heights was conducted using SAP2000 software. The results of elevated water tanks with slit and solid reinforced concrete shafts were compared. The research findings showed that during a seismic event, the slit zones increased the ductility of the shaft, reduced stress concentration in the lower part of the shaft, and provided uniform stress distribution throughout the shaft's height. The effect of the innovative system is especially noticeable in the elevated water tanks with tall and slender shafts.

Dynamics of polarization reversal in neodymium-doped PMN-PT ceramic

In this investigation, we present a comparative dynamic scaling analysis of switching and non-switching loops for PMN-PT ceramic and its neodymium-doped counterpart. The results demonstrate that both the samples exhibit similar scaling relations at high fields, suggesting that their distinct piezoelectric behaviour primarily stems from their polarization dynamics at low fields. For E<4kV/cm, the switching polarization for PMN-PT and Nd:PMN-PT follows the scaling relations: <ASW>=1.65*E5.89f−0.27 and <ASW>=34.5*E3.4f−0.2, respectively. On the other hand, non-switching polarization for the two samples follows the relations: <ASW>=2.26*E4.28f−0.15 and <ASW>=65.9*E1.95f−0.05, respectively. These scaling relations suggest that switching as well as non-switching polarization for Nd:PMN-PT respond faster to changing applied field as compared to their PMN-PT counterparts. We argue that the proportionality constants in two scaling relations have significant effect on the electromechanical behaviour of piezoceramics and should be evaluated in forthcoming dynamic scaling investigations. The kinetics of domain reversal, investigated using the Kolmogorov-Avrami-Ishibashi (KAI) model, suggest that the crystallographic domains in both the samples exhibit nucleation limited-switching (NLS) behaviour. We believe that our work will stimulate investigations on other piezoelectrics to corelate their functional response with the underlying dynamics and kinetics of polarization rotation.

Comparative Study and Dynamic Performance Analysis of DFIG based Wind Energy Conversion System

This paper presents a novel control strategy for wind energy conversion system for improving the dynamic stability of the system. In off-grid applications, the load voltage and frequency should be managed in steady-state and transient circumstances. For rural areas with unpredictable wind and load circumstances, electricity quality and control are crucial tasks. In order to improve power quality, dynamic stability and power management in direct drive standalone wind energy systems, this research provides a coordinated proportional resonant (PR) controller. Under different operating situations, such as variable wind with step increases and decreases in wind velocity, balanced and unbalanced load conditions, the dynamic performance of a doubly-fed induction generator (DFIG) is evaluated. In order to meet the load requirement, the suggested PR control technique with battery energy controller also provides efficient power balancing between the wind and battery sources. A fair performance comparison is made between the proposed control strategy and conventional vector control strategy by using the MATLAB/SIMULINK platform under varying wind and load circumstances. The proposed control approach shown better dynamic stability, improving the power quality of the system and better synchronization.

Enhancing seismic performance of brace frame using self-centering friction damper with variable slip stiffness

A novel self-centering friction damper with variable slip stiffness (VSFD) is proposed to achieve ideal self-centering capability and limit the responses of the brace frame structure under the extremely rarely occurring earthquake (EROE), and its critical difference from the self-centering friction damper with constant slip stiffness (CSFD) is the hardening post-yielding stiffness. Through mechanical analysis, the VSFD exhibits ideal flag-shaped hysteretic behavior with the desired self-centering and energy dissipation capacity. The experimental study confirms that the hysteretic behavior of the VSFD is affected by friction coefficient, slope angle and transverse compressive force. The combination of disc spring stacks with various stiffness can provide variable compressive stiffness for the VSFD. The ratio of the residual sliding load to the initial sliding load increases with pre-compressive force, and so does the self-centering capacity. The hardening post-yielding stiffness ratio is proportional to the ratio of strong to weak stacks of the disc springs. The displacement corresponding to the hardening point decreases as the preloading weak stacks’ deformation capacity decreases. The VSFD can dissipate energy even if the deformation is small, and the damping ratio drops with increasing deformation, pre-compressive force and compressive stiffness. The updated displacement-based design procedure is proposed and the comparative dynamic time history analysis is conducted for the brace frames with different kinds of braces. The results show that the seismic responses of brace frames with the CSFDs and VSFDs are comparable under the rarely occurring earthquake (ROE), which meet the performance objectives, while the latter has smaller displacement response and larger floor acceleration than the former owing to its hardening post-yielding stiffness. Due to the considerable residual deformation under the ROE and EROE, the response of brace frame with the conventional friction dampers (CFDs) differs dramatically.

Agricultural workers’ labour satisfaction dependence in Russia with the use of the internet in professional activities

Digitalization process in the Russian agro-industrial complex is connected with an increase in the need for highly qualified personnel with competencies in the field of information and communication technologies. One of the most important incentives for consolidation highly professional personnel in rural areas is a high degree of employee satisfaction with the results of their work. The article purpose is to determine the influence degree of the Internet use by Russian agricultural workers for professional purposes on various aspects of their labour satisfaction. Based on data from The Russia Longitudinal Monitoring Survey – Higher School of Economics (RLMS-HSE) from 2010 to 2021, a various aspects’ comparative dynamic analysis of the labour satisfaction level of Internet users and non-users for production purposes, as well as the dynamics analysis of the Internet use by agricultural workers with the dynamics of job satisfaction level various aspects was carried out. Correlation analysis determined the influence degree of professional Internet use on the level of labour satisfaction; a dependence modeling between various aspects of labour satisfaction on the using the Internet intensity for professional purposes was accomplished. It is established that the information and communication technologies’ use increases the degree of satisfaction with various aspects of labor activity, having a special impact on professional growth opportunities. However, the growth of digital competencies raises the employees’ ambition level and, accordingly, decreases the level of his or her labour satisfaction. In order to consolidate highly professional personnel in the industry, a multi-faceted approach is needed, including all possible mechanisms of social and economic support that contribute to growth the satisfaction level of an agricultural employee with the results of his or her labor activity.

Comparative computational fluid dynamic analysis between split and dual serpentine flow field for proton exchange membrane fuel cells

Comparative computational fluid dynamic analysis between split and dual serpentine flow field for proton exchange membrane fuel cells

Computational multi-target approach to target essential enzymes of Leishmania donovani using comparative molecular dynamic simulations and MMPBSA analysis.

Visceral leishmaniasis (VL) is caused by Leishmania donovani. The purine and pyrimidine pathways are essential for L. donovani. Simultaneously inhibiting multiple targets could be an effective strategy to eliminate the pathogen and treat VL. We aimed to target the essential enzymes of L. donovani and inhibit them using a multi-target approach. A systematic analytical method was followed, in which first reported inhibitors of two essential enzymes (adenine phosphoribosyl-transferase [APRT] and dihydroorotate dehydrogenase [DHODH]) were collected and then ADMET and PASS analyses were conducted using the Lipinski rule and Veber's rule. Additionally, molecular docking between screened ligands and proteins were performed. The stability of complexes was analyzed using molecular dynamics (MD) simulations and MMPBSA analysis. Initially, 6,220 unique molecules were collected from the PubChem database, and then the Lipinski rule and Veber's rule were used for screening. In total, 203 compounds passed the ADMET test; their antileishmanial properties were tested by PASS analysis. As a result, 15 ligands were identified. Molecular docking simulations between APRT or DHODH and these 15 ligands were performed. Four molecules were found to be plant-derived compounds. Lig_2 and Lig_3 had good docking scores with both proteins. MD simulations were performed to determine the dynamic behavior and binding patterns of complexes. Both MD simulations and MMPBSA analysis showed Lig_3 is a promising antileishmanial inhibitor of both targets. Promising plant-derived compounds that might be used to combat VL were obtained through a multi-target approach.

Cell-Population Dynamics in Diffuse Gliomas during Gliomagenesis and Its Impact on Patient Survival

Diffuse gliomas continue to be an important problem in neuro-oncology. To solve it, studies have considered the issues of molecular pathogenesis from the intratumoral heterogeneity point. Here, we carried out a comparative dynamic analysis of the different cell populations' content in diffuse gliomas of different molecular profiles and grades, considering the cell populations' functional properties and the relationship with patient survival, using flow cytometry, immunofluorescence, multiparametric fluorescent in situ hybridization, polymerase chain reaction, and cultural methods. It was shown that an increase in the IDH-mutant astrocytomas and oligodendrogliomas malignancy is accompanied by an increase in stem cells' proportion and mesenchymal cell populations' appearance arising from oligodendrocyte-progenitor-like cells with cell plasticity and cells' hypoxia response programs' activation. In glioblastomas, malignancy increase is accompanied by an increase in both stem and definitive cells with mesenchymal differentiation, while proneuronal glioma stem cells are the most likely the source of mesenchymal glioma stem cells, which, in hypoxic conditions, further give rise to mesenchymal-like cells. Clinical confirmation was a mesenchymal-like cell and mesenchymal glioma stem cell number, and the hypoxic and plastic molecular programs' activation degree had a significant effect on relapse-free and overall survival. In general, we built a multi-vector model of diffuse gliomas' pathogenetic tracing up to the practical plane.

Comparative dynamic analysis of SCR and LWR in the coupled platform–mooring–riser system under internal solitary wave conditions

As a frequently occurring and widely distributed environmental load, an internal solitary wave (ISW) always appears with a large amplitude and may result in the instability of deepwater structures and offshore accidents. In this study, a self-developed program was established to describe the dynamic behavior of a coupled platform–mooring–riser system. The response of the platform is based on the rigid body dynamics theory, that of the risers/mooring lines is obtained by the lump mass method, and the coupled effect between them is achieved by a semi-coupled analysis. Two types of riser configurations, steel catenary risers (SCRs) and lazy-wave steel catenary risers (LWRs), in the coupled system were compared under only ISWs and combined excitation of ISWs and random waves. The numerical results were proven to be reliable through validation against previous literature. The results show that different riser configurations have little influence on the platform response or mooring top tension. Both riser configurations exhibit a second-order deformation mode along the riser length and a half-wave shape with time. Additionally, a mutation in the horizontal tension, shear force, and bending moment occurs near the ISW interface. Compared with SCRs, LWRs always produce larger motion characteristics and responses with time differences owing to their complex configuration.

Comparative dynamic analysis of two-rotor wind turbine on spar-type, semi-submersible, and tension-leg floating platforms

Multi-rotor floating offshore wind turbines have been recently proposed as an innovative technology to further reduce the cost of offshore wind energy. Even though examples of commercial prototypes are present, the literature lacks studies on the dynamic performance of such systems. This work presents a comparative analysis of a two-rotor wind turbine concept mounted on spar-type, semi-submersible, and tension-leg platforms. Their short-term performance is assessed by considering six different load cases considering directionally congruent turbulent wind profiles and irregular sea states. The analysis is carried out through an in-house fully-coupled code developed in Modelica. AeroDyn v15 within FAST v8 by NREL is coupled to the Modelica code to achieve blade-element momentum capabilities. Results indicate that platform yaw motion is an important dynamic mode of the systems, particularly for the spar configuration. Stiffer station-keeping lines and longer fairlead distance to the platform centerline reduce significantly yaw motion, as in the case of the semi-submersible and tension-leg configurations. Large tower base bending moment standard deviations and the associated concentration of energy at the platform heave and pitch motion frequencies indicate an increased risk for fatigue damage for the TLP configuration, especially at above-rated wind speeds. Moreover, large tendon loads can pose concerns in terms of fatigue and limit state performance. Large mean platform pitch angle and yaw standard deviation contribute to the reduction of electric power output quality. Extreme storm conditions greatly increase the response standard deviation, especially for the semi-submersible configuration.

Comparative dynamic analysis of carbon, aramid and glass fiber reinforced interply and intraply hybrid composites

This study presents a comparative dynamic analysis of hybrid composites, which are suitable for new technological vehicles and possess greater advantages over non-hybrid fiber-reinforced composites. In this context, non-hybrid (NH), interply hybrid (IN) and intraply hybrid (IR) composites are manufactured. In the manufacturing process, NH and IN composites are utilized by using Carbon (C), Aramid (A), and Glass (G) while IR composites are manufactured with Aramid-Carbon (AC), Carbon-Glass (CG), Glass-Aramid (GA). In the manufacturing stage, a variety of layer numbers and fiber orientation angles is taken into consideration to determine the most advantageous structures for vibration characteristics. As there are a great number of productions required because of the parameters of interest, Taguchi production design is used. These composites are manufactured using Vacuum Assisted Resin Transfer Molding (VARTM). In accordance with the relevant standards, density, tensile, and dynamic properties are determined experimentally. Further, numerical models are developed using the ANSYS® software, and modal analysis is conducted. The results of the numerical analysis are compared with the experimental results. Taguchi analyses are performed to determine the most effective manufacturing configurations for the purpose. Consequently, IN and IR composites with similar content are compared to each other and the previous literature. According to the experimental and numerical results, the factors most effective in determining the natural frequency and damping ratio are layer numbers, orientation angles, and fabric types, respectively. The effectiveness of each parameter in the ranking is determined by using Taguchi levels.

A comparative dynamic analysis between model predictive torque control and field‐oriented torque control of IM drives for electric vehicles

This article compares two torque control methodologies, model predictive control (MPC), and field-oriented control (FOC), for induction motor (IM) control over a wide speed range applied to an electric vehicle driving system (EVDS). The control technologies are designed and developed to control torque to achieve targeted traction according to vehicle specifications and the demands of the driver. For both control techniques, the specified electric vehicle (EV) is driven under and above base speed with stator flux control and field weakening control of the IM, respectively. In EVDS, the dynamic modeling of the power plants, that is, vehicle dynamics, Li-ion battery, IM, and road forces, is considered. The dynamic behavior of the EVDS of a four-passenger city EV is analyzed and evaluated with urban dynamometer driving schedule (UDDS) driving cycle. From simulations and performance appraisal, the comparison between FOC and MPC is investigated.

Reduced-Order Modeling and Comparative Dynamic Analysis of DC Voltage Control in DC Microgrids Under Different Droop Methods

Droop control has been well adopted for multi-source multi-load DC microgrids (MGs) due to its inherent modularity and reliability by only using local measurements, especially with the most commonly-used voltage-current droop ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">V-I</i> ) mode. While another implementation named current-voltage droop ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">I-V</i> ) mode also can be adopted. With the same value of droop gain in these two modes, a DC MG will have the same steady-state feature, but its dynamic performance of DC voltage control may be different. Our primary motivation is to investigate this phenomenon from the perspective of equivalent <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">RLC</i> circuits. This paper proposes a generic reduced-order modeling method suitable for exploring the dynamic stability of DC voltage control with these two modes. By ignoring fast inner current control dynamic, each droop based DC voltage control unit can be modeled as a <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">RLC</i> parallel circuit in these two modes, which is convenient for modular modeling and extension. With these models, the essential cause of system dynamic stability difference and the physical meaning of key control parameters in these two modes can be revealed in an intuitive way. In addition, if the inner current control with slow dynamic cannot be ignored in some specific scenarios, a modified <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">RLC</i> model can be still obtained to analyze its influence. Moreover, based on reduced-order models, analytical solutions of dynamic performance indexes have been obtained, through which the impact of control parameters on dynamic performance of DC bus voltage can be characterized. Finally, the effectiveness of the proposed reduced-order modeling method has been verified by detailed simulation and experiment results.

Banking and Money in an Extended Solow-Uzawa’s Neoclassical Growth Model

Abstract This study deals with interactions between economic growth and structural change with banking. The study is influenced by the growth model of money and banking by Chang et al. (2007). It deviates from Chang et al.’ model with regard to the monetary authority behavior, economic structure, and modeling behavior of household. The model deals with dynamic interactions between money, banking, economic structural change and growth in a perfectly competitive economy. The economic system consists of one capital goods sector, one consumer goods sector, and one banking sector. The two goods sectors are based on the Solow-Uzawa growth model. The motion is described by a set of differential equations. For illustration, we simulate the motion of the economic system. We identify the existence of a stable equilibrium point. We carry out comparative dynamic analysis. The comparative analyses provide some insights into the complexity of economic growth with banking.

Comparative static and dynamic analysis of single‐ and double‐stage multifunctional 3‐phase grid‐tied photovoltaic systems

This paper presents a comparison analysis involving four multifunctional grid-tied photovoltaic (MPV) systems, divided in single-stage and double-stage architectures. The functionalities can be pointed out as generation/injection of active energy into the utility grid, and active power conditioning including reactive power and load unbalance compensation, as well as load harmonic currents suppression. Thus, beyond the photovoltaic systems' conventional functions, the MPV systems also contribute to improve power quality indicators. Single-phase full-bridge (1-FB) inverters are used to build two grid-tied inverter configurations. In the first, called as MPV-FB, three 1-FB inverters share the same DC-bus, while in the second, named as MPV-3FB, each of the three 1-FB inverters operates with an individual DC-bus. Each inverter configuration integrates the MPV system architectures with single-stage and double-stage, where in the single-stage configuration the photovoltaic array is directly connected to the inverter DC-bus, whereas in the DS one, a step-up DC–DC converter is inserted between the photovoltaic array and the inverter DC-bus. Under several scenarios of operation, the four MPV systems named as MPV-FB-SS, MPV-FB-DS, MPV-3FB-SS and MPV-3FB-DS, are experimentally tested to compare constructive aspects, evaluate static/dynamic performances and power quality issues, as well as capability to operate with photovoltaic array failure.