Computational Dynamics Model Research Articles

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

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.

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).

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.

Pi-based biochemical mechanism of endurance-training-induced improvement of running performance in humans.

Endurance training improves running performance in distances where oxidative phosphorylation (OXPHOS) is the main ATP source. Here, a dynamic computer model is used to assess possible biochemical mechanisms underlying this improvement. The dynamic computer model is based on the "Pi double-threshold" mechanism of muscle fatigue, according to which the additional ATP usage appears when (1) inorganic phosphate (Pi) exceeds a critical value (Picrit); (2) exercise is terminated because of fatigue, when Pi reaches a peak value (Pipeak); (3) the Pi increase and additional ATP usage increase mutually stimulate each other. The endurance-training-induced increase in oxidative phosphorylation (OXPHOS) activity attenuates the reaching of Pipeak by Pi (and thus of O2max by O2) at increased power output. This in turn allows a greater work intensity, and thus higher speed, to be achieved before exercise is terminated because of fatigue at the end of the 1500m run. Thus, identical total work is performed in a shorter time. Probably, endurance training also lowers Pipeak, which improves the homeostasis of "bioenergetic" muscle metabolites: ADP, PCr, Pi and H+ ions. The present dynamic computer model generates clear predictions of metabolic changes that limit performance during 1500m running. It contributes to our mechanistic understanding of training-induced improvement in running performance and stimulates further physiological experimental studies.

Assessing carbon capture and storage technology in industrial joint venture

Carbon Capture and Storage (CCS) technology can effectively reduce carbon dioxide emissions from industrial and energy production processes. Yet the commercialization of CCS technology is hampered by financial requirements. Existing research compares the costs and benefits of business models for individual CCS projects, no studies assess the industry and national levels. Here we use a dynamic computable general equilibrium model, constructure the vertical integration and joint venture business models for CCS. This study assesses the emission and economic impacts of joint ventures between China's high-emission industries and their upstream and downstream sectors. We find that adopting the joint venture model in the coal power sector, compared to the vertical integration model, initially exerts a negative economic impact but can mitigate 0.04 % of GDP by 2060. The chemical industry consistently benefits from the joint venture model both economically and in emission reductions. Downstream sectors of the steel and cement industries are unsuitable for participation in joint ventures. In addition, the joint venture model has significant industry linkage effects, affecting energy consumption, the scale and cost of CCS deployment. This work provides important information for the large-scale commercialization of CCS technology.

The Impact of Dynamic Effects on the Results of Non-Destructive Falling Weight Deflectometer Testing.

The article investigates the impact of applying a dynamic computational model that considers inertia forces on pavement deflections under rapidly changing loads over time. This study is particularly relevant to the modelling of falling weight deflectometer (FWD) testing. Initially, the article examines the deflection values obtained from computational models under loads with varying frequencies. In this context, considering inertia forces was significant for load durations shorter than 0.04 s. In such cases, the results of static and dynamic analyses differed considerably. One application of FWD measurement results is determining the stiffness moduli of pavement layers using backcalculation. The study explored the impact of incorporating inertia forces into the pavement model on the estimated values of stiffness moduli obtained via backcalculation. The results revealed differences of several percent between the stiffness moduli calculated using dynamic and static numerical models. Subsequently, the key pavement deformations and fatigue life were determined using the obtained moduli. Again, significantly different results were observed between dynamic and static cases. Based on these findings, it can be concluded that dynamic effects should not be ignored when using FWD testing for backcalculation. Additionally, the article addresses the sensitivity of backcalculation results, which is crucial for the accurate interpretation of the obtained data.

On the positive economic impacts of port infrastructure development and seaborne trade efficiencies in Sub-Saharan Africa: the case of Senegal

AbstractInefficient port infrastructures is one of the challenges facing Sub-Saharan Africa, particularly as regards the West African region’s economic progress. Using a dynamic computable general equilibrium model, the paper examines how improving port infrastructure in Senegal can increase the potential of seaborne trade, and accelerate economic and social development in the country and the wider region. Despite Senegal's strategic location along the Trans-Saharan trade route in West Africa, infrastructural limitations pose challenges to port capacity. Our findings suggest that improving port infrastructure can increase port productivity, leading to a reduction in costs of imported food products and domestic inputs. As a result, the country's competitiveness in international markets would be enhanced and could stimulate the production of cash crops, industrial food, and chemical products. This would lead to increased food supply and improved purchasing power, supporting the country's food security. Results show that increased efficiencies in maritime exports and imports lead to an overall increase in economic activity, resulting in significant GDP growth, improved welfare, and a reduction in poverty incidence. This growth can be attributed to higher exports and greater availability of imported intermediate inputs at lower prices, making exports more competitive in the global market as export prices decrease.