Computational Dynamics Model Research Articles

Measuring impacts of retirement age extension on economic growth and labor market in China using a recursively dynamic CGE model

This paper estimates the effects of retirement age extension on China’s economic growth and employment from 2020 to 2050 using a dynamic computable general equilibrium model. This paper focuses on the interaction between retirement and youth employment, particularly the substitution between young and older workers and the trade-off between male and female workers. According to the reform speed of the retirement system, nine policy scenarios are designed, which are divided into three policy options: slow, gradual, and fast reform. The simulations indicated the extension of the retirement age will indeed have a positive impact on China’s GDP growth and the optimal policy is to gradually delay the female retirement age from 50 to 60. Meanwhile, the share of women in their 30s and 50s in total labor demand is intended to increase by 2.01–2.05%, while the employment share of young and middle-aged men will decline by 1.32–1.68%.

Using ansys fluent udf for numerical study of the movement of the rollers of a downhole positive displacement pump

In order to improve the design and increase the technical characteristics of pump and compressor equipment, computational modeling of fluid dynamics is used. Numerical research techniques of positive displacement machines are quite diverse and are widely used for vane and gerotor pumps. The roller rotary pump considered in this work is used for oil production in the sidetracks of oil wells. The difference in the design is the use of rollers as partitions separating the working chambers of the pump. The authors of the article propose a method for studying the movement of rollers in the Ansys (Fluent) software package, and related issues of creating userdefined functions (UDF) to describe reciprocating motion using the macro DEFINE_CG_MOTION (name, dt, vel, omega, time, dtime). It is shown that the result of calculating the movement speed in ansys fluent differs from the graph of the given function. A sine law is substantiated to describe the speed of movement of the roller’s center of mass. The method for determining the coefficients in a sinusoidal dependence is described and it is shown how these coefficients affect the movement of the roller. The results obtained in the study can be used when performing verification of analytical calculation methods with finite element modeling data using UDF Ansys, and will also help young researchers understand the writing of UDF DEFINE_CG_MOTION. Keywords: fuel and energy complex; oil and gas industry; well equipment; volumetric pump; Computational Fluid Dynamics (CFD); numerical simulation; moving mesh; User Define Function (UDF).

Computational modeling of selective attention differentiates subtypes of amnestic mild cognitive impairment

ABSTRACT Individuals with amnestic mild cognitive impairment (aMCI), a prodromal stage of Alzheimer’s disease and other dementias, show inhibition deficits in addition to episodic memory. How the latent processes of selective attention (i.e., from perception to motor response) contribute to these inhibition deficits remains unclear. Therefore, the present study examined contributions of selective attention to aMCI-related inhibition deficits using computational modeling of attentional dynamics. Two models of selective attention – the dual-stage two-phase model and the shrinking spotlight model – were fitted to individual participant data from a flanker task completed by 34 individuals with single-domain aMCI (sdaMCI, 66–86 years), 20 individuals with multiple-domain aMCI (mdaMCI, 68–88 years), and 52 healthy controls (64–88 years). Findings showed greater commission errors in the mdaMCI group compared to controls. Final-fitting model parameters indicated inhibitory and early perceptual deficits in mdaMCI , and impaired spatial allocation of attention in both MCI groups. Model parameters differentiated mdaMCI from sdaMCI and controls with moderate-to-high sensitivity and specificity. Impairments in perception and selective attention may contribute to inhibition deficits in both aMCI subtypes.

Impacts of Re-export Demand on Benin’s Economy

This article analyses the impact of re-export demand on the Beninese economy. Re-export is dominant in Benin’s trade and may represent risks to the economy’s vulnerability. The methodology uses a dynamic computable general equilibrium model. It simulates two scenarios: the first considers a one-off decline in re-export demand in the first year, while the second analyses the impact of a recurring annual shock. The results, both at the aggregate and sectoral levels, indicate that the decline in re-export demand would negatively affect real GDP, domestic and net external demand, and most industries. This article extends the existing knowledge on the re-export phenomenon by adding a dynamic analysis of its potential impact at the aggregate and sectoral levels. The results confirm that re-export is a source of vulnerability for the Beninese economy. The authorities should focus on diversifying the economy and strengthening the competitiveness of the Port of Cotonou, in order to mitigate vulnerabilities linked to re-export activities. JEL Codes: C68, F17

Computational modeling of hydrogen behavior and thermo-pressure dynamics for safety assessment in nuclear power plants

Following the Three Mile Island Nuclear Generating Station incident 1979, extensive research has focused on preventing hydrogen accumulation and explosions during nuclear power plant emergencies. We used advanced computational fluid dynamics (CFD) simulations to analyze hydrogen distribution, pressure dynamics, and the efficacy of safety measures across various containment structures under accident scenarios. Results indicate that smaller containment structures experience rapid hydrogen accumulation, reaching a peak pressure of 2.5 bars and a temperature of 120 °C within the first 30 s. Structural integrity is compromised at pressures around 3.8 bars, leading to failure within 10 min under sustained high pressure. In contrast, larger containment structures exhibit delayed pressure buildup, peaking at 2.3 bars with a corresponding temperature of 110 °C, and maintain integrity for up to 30 min. Fire scenarios demonstrate that smaller containment structures reach peak temperatures of 500 °C, which resulted in partial structural failure, whereas larger containments withstand up to 450 °C for 40 min without compromise. When hydrogen concentrations exceed 35%, and temperatures surpass 1430 °C, explosion risks increase substantially, which reduces the effectiveness of passive mitigation systems.

Optimum low-carbon transformation pathways of China’s iron and steel industry towards carbon neutrality based on a dynamic CGE model

Low-carbon transformation pathways of the iron and steel industry play a significant role towards achieving the carbon neutrality target by 2060. This study explores the low-carbon transformation pathways of China’s iron and steel industry in 2060 under different emission reduction policy scenarios by adopting a modified dynamic computable general equilibrium model. We found that: (1) China’s crude steel production will peak in 2024–2026, with a value of approximately 10.49 × 102–11.11 × 102 Mt. (2) Four integrated policy scenarios (C1T1E2: carbon trading policy, carbon tax, and renewable energy policy; C1T6E2; C6T1E2; and C6T6E2) have the most potential to achieve the carbon neutrality target by 2060; their remaining CO2 emissions are 2.52 × 102, 1.99 × 102, 1.21 × 102 and 0.69 × 102 in 2060, respectively. (3) The projected CO2 emissions per ton steel from 2020 to 2060, of which the impact degree in the carbon trading market policy scenario shows the most difference, fluctuated from 0.81 t CO2/t under the C1 scenario to 0.42 t CO2/t under the C6 scenario in 2060. (4) The reduction degree of energy consumption per ton steel performed the best in the integrated policy scenarios, of which the integrated C6T6E2 scenario (82 kgce/t in 2060) had the most effect on energy consumption per ton steel, followed by C6T1E2 (101 kgce/t) and C1T6E2 (125 kgce/t).

A computational dynamic systems model for in silico prediction of neural tube closure defects

A computational dynamic systems model for in silico prediction of neural tube closure defects

Isoreticular Contraction in Dicopper Paddle-Wheel-Based Metal-Organic Frameworks to Enhance C2H2/CO2 Separation.

Achieving a balance between high selectivity and uptake is a formidable challenge for the purification of acetylene from mixtures with carbon dioxide, particularly when seeking to maximize both C2H2 adsorption capacity and C2H2/CO2 separation selectivity in crystalline porous materials. In this study, leveraging the principles of reticular chemistry, we selected two tetracarboxylate-based linkers and combined them with Cu2+ ions to synthesize two isoreticular dicopper paddle-wheel-based metal-organic frameworks (MOFs): Cu-TPTC (terphenyl-3,3',5,5'-tetracarboxylic acid, H4TPTC) and Cu-ABTC (3,3,5,5-azobenzenetetracarboxylic acid, H4ABTC). The structural and sorption analyses revealed that Cu-ABTC, despite having slightly smaller pores due to the strategic replacement of a phenyl ring with an azo group between two tetratopic ligands, maintains high porosity compared to Cu-TPTC. Furthermore, Cu-ABTC outperforms Cu-TPTC in terms of C2H2 adsorption capacity (196 cm3 g-1 at 298 K and 1 bar) and C2H2/CO2 separation selectivity (16.5~5.6). These findings were corroborated by dynamic breakthrough experiments and computational modeling. This research highlights the potential of the isoreticular contraction strategy in enhancing MOFs for sophisticated gas adsorption and separation processes.

Beyond IC50-A computational dynamic model of drug resistance in enzyme inhibition treatment.

Resistance to therapy is a major clinical obstacle to treatment of cancer and communicable diseases. Drug selection in treatment of patients where the disease is showing resistance to therapy is often guided by IC50 or fold-IC50 values. In this work, through a model of the treatment of chronic myeloid leukaemia (CML), we contest using fold-IC50 values as a guide for treatment selection. CML is a blood cancer that is treated with Abl1 inhibitors, and is often seen as a model for targeted therapy and drug resistance. Resistance to the first-line treatment occurs in approximately one in four patients. The most common cause of resistance is mutations in the Abl1 enzyme. Different mutant Abl1 enzymes show resistance to different Abl1 inhibitors and the mechanisms that lead to resistance for various mutation and inhibitor combinations are not fully known, making the selection of Abl1 inhibitors for treatment a difficult task. We developed a model based on information of catalysis, inhibition and pharmacokinetics, and applied it to study the effect of three Abl1 inhibitors on mutants of the Abl1 enzyme. From this model, we show that the relative decrease of product formation rate (defined in this work as "inhibitory reduction prowess") is a better indicator of resistance than an examination of the size of the product formation rate or fold-IC50 values for the mutant. We also examine current ideas and practices that guide treatment choice and suggest a new parameter for selecting treatments that could increase the efficacy and thus have a positive impact on patient outcomes.

Community-based propagation to scale up educational innovations in sustainability

Many high-quality educational innovations are freely available, and some are known to motivate evidence-based climate and sustainability action. Typically, efforts to propagate educational innovations rely on outreach and word-of-mouth diffusion, but these approaches tend to achieve little. We develop and analyse a dynamic computational model to understand why and to test other propagation strategies. Our analysis reveals that outreach has limited impact and does little to accelerate word-of-mouth adoption under conditions typical in higher education. Instead, we find that community-based propagation can rapidly accelerate adoption, as is also shown by a small number of successful real-world scaling efforts. This approach supports a community of ‘ambassadors’, facilitating and rewarding their sharing the innovation with potential adopters. Community-based propagation can generate exponential growth in adopters, rapidly outpacing outreach and word-of-mouth propagation. Without it, we are unlikely to rapidly scale the educational innovations needed to build urgently needed capacity in sustainability.

Systemic risk in banking, fire sales, and macroeconomic disasters

We develop a dynamic computational network model of the banking system where fire sales provide the amplification mechanism of financial shocks. Each period a finite number of banks offers a large, but finite, number of loans to households. Banks with excess liquidity also offer loans to other banks with insufficient liquidity. Thus, each period an interbank loan market is endogenously formed. Bank assets are hit by idiosyncratic shocks drawn from a thin tailed distribution. The uneven distribution of shocks across banks implies that each period there are banks that become insolvent. If insolvent banks happen also to be heavily indebted to other banks, their liquidation can trigger other bank failures. We find that the distribution across time of the growth rate of banking assets has a ‘fat left tail’ that corresponds to rare economic disasters. We also find that the distribution of initial shocks is not a perfect predictor of economic activity; that is some of the uncertainty is endogenous and related to the structure of the interbank network.

Impacts on Regional Growth and “Resource Curse” of China’s Energy Consumption “Dual Control” Policy

Accurately evaluating the effectiveness of the energy consumption “dual control” policy can effectively solve serious the current environmental pollution and promote ecological civilization. However, researchers have rarely considered the impacts on the regional “resource curse” of the energy consumption “dual control” policy. A dynamic computable general equilibrium model (CGE) was built to evaluate the impacts on the regional “resource curse” of the energy intensity control and total energy control policy. The results showed the following. (1) The energy consumption “dual control” policy changes the supply-and-demand relationship of factors and reduces the crowding-out effect of humans and capital. (2) The energy consumption “dual control” policy has restrained GDP growth, and the total output and total investment have declined. However, the impact in regions without the “resource curse” is remarkable. (3) The energy consumption “dual control” policy has a significant inhibitory effect on major pollutants and carbon emissions. (4) The energy consumption “dual control” policy has played a positive role in breaking the regional “resource curse”. The areas with a high and low “resource curse” have become smaller, and the areas without the “resource curse” have increased significantly. The following suggestions are made: (1) increase the flexibility of the “dual control” policy of energy consumption, (2) establish an energy consumption budget management system, and (3) accelerate the establishment of a carbon footprint management system.

Contribution of the plantar fascia and long plantar ligaments to the stability of the longitudinal arch of the foot

The contribution of the Plantar Fascia (PF) and Long Plantar Ligament (LPL), two ligaments extending from the hindfoot to the forefoot, to arch stability has been studied in the past using in vivo, in vitro, and in silico methodologies. In silico studies were based on one single model obtained from one single subject and did not account for the known inter-subject morphological and biomechanical variations. In the present study, we developed computational dynamic models of nine different legs obtained from nine different individuals to evaluate the role of the LPL and PF in arch support, accounting for biological differences between subjects. These models were validated by comparing the simulation results against experimental results from the corresponding cadaver legs. After validation, we simulated body weight conditions for each model by applying a vertical load to the tibia, starting from zero and increasing linearly to 720 N. Kinematic and dynamic parameters, including the variation of the medial arch angle and of the navicular height, as well as the passive forces developed by the LPL and PF, were used to evaluate the contribution of these ligaments to arch support under body weight. The results indicate that a total collapse of the medial longitudinal arch occurred only when both the LPL and PF were absent, but a stable arch was maintained when either one of these two ligament structures were present. The results varied significantly among the specific models, highlighting the importance of using multiple models to account for inter-subject morphological differences.

Computational fluid-particle dynamic model guiding bioengineered magnetic nanomedicine for personalized brain-targeted drug delivery

Computational fluid-particle dynamic model guiding bioengineered magnetic nanomedicine for personalized brain-targeted drug delivery

Governance and policy implications of the Inflation Reduction Act: A European perspective

AbstractThis paper examines the US 2022 Inflation Reduction Act (IRA) alongside the EU's Net‐Zero Industry Act (NZIA) and Critical Raw Materials Act (CRMA) of 2023. We analyze their differential approaches to accelerating investment in clean technology, enhancing energy security and fortifying supply chains. Both regions share the objective of diminishing reliance on Chinese dominance in clean industries. The US seeks to stimulate private investment primarily via uncapped tax credits from 2022 to 2031, some of them subject to stringent domestic content requirements. The EU has reacted to the potential violation of World Trade Organization's rules and a possible green investment shift to the US In doing so, the EU is relying heavily on a regulatory strategy, with emphasis on the simplification of procedures. However, the EU's public funding model is vague and leaves details to the discretion of member states, risking fragmentation within the single market. Through the application of a dynamic computable general equilibrium model, we show that a 50% increase in demand for the IRA's uncapped tax credits could nearly triple US GDP outcomes by 2027. We highlight the contrast between the IRA's immediate fiscal incentives and the NZIA's regulatory approach, emphasising that the former are more attractive for firms.

Possible development path for agricultural economic and trade cooperation in FTAAP: A numerical simulation

Exploring the path of developing agricultural economy and trade cooperation in the Free Trade Area of the Asia Pacific (FTAAP) is of great practical significance for deepening economic integration in the Asia Pacific region and strengthening regional agricultural development. This paper proposes three feasible paths based on RCEP, CPTPP, and the integration of RCEP and CPTPP to establish FTAAP. Moreover, a dynamic computable general equilibrium model of global trade is used to simulate the macroeconomic effects and the agricultural effects represented by China in forming FTAAP under these three paths. The research results show that six common policy nodes will promote macroeconomic growth in participating countries, and the effects of the in-depth implementation of RCEP and CPTPP will be greater than those of the initial implementation. Due to the broader base of participating economies and the higher level of openness, establishing FTAAP under Path 3 will yield greater macroeconomic effects and agricultural effects. Therefore, the path based on the integration of RCEP and CPTPP is an optimal selection for economic and trade cooperation of agriculture in FTAAP. All parties should actively overcome the obstacles to forming FTAAP and provide a stable internal and external industrial development environment for regional agricultural economic and trade cooperation.

Dynamic fluid flow model for phosphate slurry pipeline: OCP main pipeline as case study

The transportation of phosphate slurry through large-scale pipelines presents significant challenges due to the complex behavior of multiphase flows, particularly with varying solid content, density, and dynamic viscosity. Efficient and accurate prediction of flow behavior is critical for optimizing the operation of such pipelines. This work aims to develop a dynamic computational model to simulate phosphate slurry flow in pipelines. The case study focuses on the OCP Group’s main slurry pipeline, which links the mining sites at Khouribga to the industrial plants at Jorf Lasfar, Morocco. This pipeline system spans a total length of 187.124 km, consisting of 5237 pipes with an inner diameter ranging from 0.8546 m to 0.8578 m, and features several elevation changes along its ground level. Using a section-averaged, dynamic approach and the Finite Volume scheme, the model computes essential flow parameters, including density, dynamic viscosity, and pressure, for the incompressible and non-Newtonian slurry and process water flows. The model’s accuracy is validated against on-site measured data, showing an average deviation of ±0.32% for outlet density, and below 10% for pressure along the pipeline, underscoring the model’s reliability. Additionally, a sensitivity analysis was conducted to illustrate the impact of key parameters on the predicted head losses and pressures along the pipeline. This analysis shows that the slurry viscosity is the most critical parameter, significantly influencing these predictions. This model provides high accuracy and reasonable CPU time for real-time simulation and monitoring, while also offering significant potential for optimizing pipeline operations and ensuring the reliability of phosphate transport.

Structural System and Computational Dynamic Model of a Life-Saving Multi-Storey Building with a Kinematic Seismic Isolation System

Introduction. In design of a life-saving multi-storey building, a seismic isolation system in the form of the kinematic supports is used to ensure the seismic resistance and reduce the seismic loads. The structural system, the computational dynamic model and the results of the intermediate in-situ tests of a life-saving multi-storey building with a kinematic seismic isolation system being built in Grozny have been analysed in the article.Materials and Methods. The research included modeling and computation of the structural system of a building with a kinematic seismic isolation system. In-situ tests were carried out to confirm the working capacity of the seismic isolation system connections.Results. A multi-storey life-saving building was designed according to a frame-core wall structure, where the vertical load-bearing elements were core walls, columns and connections between the columns in the form of the stiffening diaphragms. The high-rise part of a building was designed using a kinematic seismic isolation system consisting of the seismic isolating concrete-filled steel tubular supports. The results of the calculations of the main and specific load combinations and internal forces in the load-bearing structures have been presented.Discussion and Conclusion. The research has shown that the use of the developed structural system of seismic isolation with kinematic supports makes it possible to reduce the seismic loads and the total weight of a building and at the same time to increase its mechanical reliability and safety. The conducted intermediate in-situ tests have confirmed the working capacity of the joints connecting the supports with the monolithic reinforced concrete structures of a building, which makes it possible to implement the kinematic seismic isolation supports into the construction industry practices.

Mathematical model for constructing a matrix of coefficients thermal conductivity under low-temperature influence on the multilayer epidermis of biological tissue

Objective. The purpose of the study is to develop a mathematical model for constructing a matrix of thermal conductivity coefficients under low-temperature exposure to the multilayer epidermis of biological tissue. Method. The research is based on methods of thermo dynamic analysis, full-scale and computational modeling of processes under low-temperature influence. Result. A mathematical model of the matrix of thermal conductivity coefficients under low-temperature effects on biological tissue has been developed. Heat transfer in a multilayer medium under low-temperature influence on biological tissue is presented as a process with a discrete step in time and coordinate. Thermal properties are evenly distributed throughout the volume of layers of biological tissue. For exposure to cold, layers of the epidermis of biological tissue were used, divided into uniform identical cells, where the cell area of the biological tissue was taken to be equal to one. Conclusion. The results obtained in this work can be useful to specialists who deal with modeling problems with free boundaries.

МОДЕЛИРОВАНИЕ ПУСКА ДВС АВТОМОБИЛЯ С БЕССТУПЕНЧАТОЙ КОРОБКОЙ ПЕРЕДАЧ

The aim of the work is to build a computer dynamic model of moving internal combustion engine parts and a continu-ously variable transmission to determine the starting characteristics of the internal combustion engine. The paper objective is to define the characteristics of moving parts of the internal combustion engine and continuously variable transmission when starting the internal combustion engine with an electric starter. The research method is computer modelling of moving internal combustion engine and transmission parts when starting with an electric starter. The novelty of the work lies in building a computer model of moving parts of an internal combustion engine and a contin-uously variable transmission, connected by a torsional vibration damper, considering changes in friction parameters. The results are in developing a computer model to determine the starting characteristics of a four-cylinder in-line four-stroke internal combustion engine with spark ignition and a continuously variable multitronic® 01J transmis-sion. To check the computer model adequacy, the author uses the values of the average friction pressure in accord-ance with GOST R 54120-2010 and empirical data on the unevenness of the angular velocity of the crankshaft. Simu-lating a four-stage start of an internal combustion engine shows that opening the cylinder valves at the 1st stage in-creases the angular velocity of the crankshaft by 4%. Temporary switching on the reverse clutch for 1.4 s reduces the amplitude of angular oscillations of the solar shaft by 2.22 times, eliminates the beating of the contacting gearbox teeth, but slows down the crankshaft speed by 7.6%. After the reverse clutch is turned off, periodic changes in the an-gular velocity of gearbox parts occur.