Dynamic Analysis Research Articles

Seismic energy and axial column demands of steel concentrically braced frames

Steel concentrically braced frames are widely used in seismic regions. Current engineering practices advocate the utilization of concentrically braced frames with elastic beams. Nevertheless, there is a noticeable dearth of comprehensive studies and recommendations regarding the seismic energy demands and axial column demands of these frames, considering the influence of varying beam strength and stiffness. To comprehensively investigate seismic energy demands and axial column demands, this study involves the design of nine concentrically braced frames characterized by different heights (3-, 9-, and 18-story) and beam strength levels (including cases of serious yielding, medium yielding, and elastic beams) for dynamic analysis. The assessment of energy demands in key structural members and axial column demands of concentrically braced frames is conducted based on the dynamic analysis outcomes. In concentrically braced frames with yielding beams, there is a noticeable reduction in the energy demands among braces, whereas the energy demands within beams experience an increase. Furthermore, it is observed that the axial column demands in concentrically braced frames featuring yielding beams are more closely associated with the overstrength of the beams rather than conforming to the full plastic mechanism as suggested by AISC 341.

Folk theorem under bankruptcy

In this paper, we examine Subgame Perfect Nash Equilibria (SPE) within an infinite horizon oligopolistic market, accounting for the possibility of firm bankruptcy. Central to our dynamic analysis is the concept of Bankruptcy-Free (BF) allocations. The consideration of bankruptcy introduces several distinctive features not encompassed by standard models of infinitely repeated games. Notably, when firms are sufficiently patient towards future outcomes, achieving certain collusive outcomes as equilibria may not be possible. We discern qualitatively different results depending on the number of firms in the market; in a duopoly, only specific BF allocations can be sustained as SPE, while in scenarios with more than two firms, allocations outside the BF set can also be sustained as SPE. In both instances, it is crucial that the payoffs are above the minimax BF payoff, a condition more restrictive than the standard minimax payoff advocated in Folk Theorems.

Dynamics and stability of neural systems with indirect interactions involved energy levels

Dynamical modelling for neural systems with direct and indirect connections is to understand how these connections contribute to neural dynamics. Despite recent findings suggesting the existence of indirect connections in neural systems, their dynamical characteristics remain poorly understood. In this paper, we propose a simplified circuit model with indirect interactions inspired by the indirect connection between two neurons, from an energy perspective. Through bifurcation and dynamics analysis, we find that the presented model has a striking resemblance with the classical Hodgkin-Huxley neuronal model. Moreover, stability in a neural network coupled with energy is demonstrated by combining stability analysis and numerical simulation. Our analysis sheds light on the excitability dynamics and multi-stability that can emerge in biophysical systems with nonlinear interactions inspired by the neural systems and highlights the role of energy in propagating electrical activities.

Numerical Analysis of Film Cooling Flow Dynamics and Thermodynamics for Perfect and Imperfect Cooling Holes

Numerical Analysis of Film Cooling Flow Dynamics and Thermodynamics for Perfect and Imperfect Cooling Holes

Exploring the dynamic evolutionary trajectories for urban residential building carbon emissions toward 2060: Evidence from the HSCW zone in China

Revealing the long-term development trajectory and peak scenarios of the urban residential building sector is crucial for formulating targeted emission reduction strategies and contributing to achieving the “Dual carbon” target. Given that, significant variables affecting carbon emissions from urban residential buildings (URBCE) at both macro and end-use building levels are identified in this study. Furthermore, an innovative dynamic simulation model is developed by integrating the Monte Carlo simulation model with the Kaya identity model, taking into account the uncertainties of the variables. Subsequently, the long-term evolution trajectories, potential emission peaks, and peak time of the URBCE close to 2060 in China’s hot summer and cold winter (HSCW) zone are simulated. Results indicate that URBCE is expected to reach its peak of 272.43 Mt CO2 in 2040 under the baseline scenario. Through the dynamic simulation, the probable peak time of energy consumption in the HSCW zone is 2044 (±1.85), with a peak of 145.42 (±6.91) Mtce, and the possible peak time of carbon emissions is probably 2039 (±1.60), with a peak of 271.93 (±13.40) Mt CO2. According to dynamic sensitivity analysis, carbon emission factor, per capita residential space, and heating energy intensity can promote the peak size and timing. These findings lay a robust foundation for the formulation of regionally specific carbon reduction targets and initiatives.

Dynamics Analysis for a Hierarchical System with Nonlinear Cut-Off Interaction and Free Will

Dynamics Analysis for a Hierarchical System with Nonlinear Cut-Off Interaction and Free Will

Dynamic analysis of carbon emissions from construction and demolition activities in Japan: Revealed by high-resolution 4D-GIS modeling

To meet the 2050 decarbonization target of the global buildings and construction sector, more attention is needed to reduce carbon emissions from construction and demolition. However, current national carbon accounting studies for these activities remain limited in spatial granularity and localized applicability. This study developed a bottom-up spatiotemporal database of carbon emissions from building construction and demolition in Japan via integrating a geographic information system-based building stock model, statistical data, and survey information. Focusing on municipal-level emissions, the Logarithmic Mean Divisia Index approach was used to decompose spatiotemporal variations and identify the contributing factors. Results indicate that carbon emissions from Japan's construction and demolition activities fell by more than 50% between 2005 and 2020, largely due to declining new/demolished-to-stock ratio, suggesting a transition to a stock-based society. Central cities' reliance on carbon-intensive buildings positively contributed to spatial variations in their construction emissions, underscoring the importance of sustainable materials and timber designs. Differences between prefectures in demolition emission intensity highlighted the strategic placement of recycling facilities in key regions to curb transportation-related emissions. Overall, these findings provided data reference for local governments to devise tailored policies for managing construction and demolition emissions.

Dynamical Analysis of Delayed Predator-Prey Models and Explicit Impacts of Harvesting

Dynamical Analysis of Delayed Predator-Prey Models and Explicit Impacts of Harvesting

Dynamical Analysis of Eco-Epidemiological Model with Fading Memory

Dynamical Analysis of Eco-Epidemiological Model with Fading Memory

Comparative Analysis of Framed-Tube & Braced-Tube System in Tall Buildings Using ETABS

Abstract: Since the rigid frame became popular in the first half of the 20th century, tall buildings with structural systems have evolved. The development of underlying frameworks for tall structures lays on reasonable realism, economy of material utilization, effortlessness and polish, and worry for constructability. We are now able to build buildings that are ever higher thanks to cutting-edge building materials, sophisticated computational software, and sturdy structural systems. The rationale behind the creation of structural systems for tall buildings is to achieve architectural expression, ensure safety and serviceability, and make rational and effective use of materials. The use of composite structures, which combine the advantages of various materials, has been the trend in structural systems for tall buildings. In both static and dynamic conditions, these high-rise structures ought to be able to withstand a variety of lateral loads, such as wind load and earthquake load. This study examines the responses of the Framed Tube, Braced Tube, structural systems to various parameters such as Story displacement, Story drift, Story shear, and time period. The analysis focuses on 60-story structures situated in Seismic Zone III with medium soil conditions. The static analysis of the structures is conducted using the linear static method, which involves wind load calculations using the force coefficient method. On the other hand, the dynamic analysis is performed using the response spectrum method, with wind load calculations carried out using the gust factor calculation method.

Analytical Study for Prjice Prediction of Bitcoin Using Machine Learning and Artificial Intelligence

Abstract: Cryptocurrency transactions rely on encryption algorithms for security and decentralization. However, traditional machine learning algorithms often struggle with the dynamic cryptocurrency market, leading to inaccuracies. To address this, integrating Integrating sentiment analysis of Twitter data alongside Bidirectional Long Short-Term Memory (BiLSTM) and Bidirectional Gated Recurrent Unit (BiGRU) models enriches the analysis of cryptocurrency market dynamics. Twitter provides dataset from kaggle open source and the sentiment expressed by users on cryptocurrencies, enabling the prediction of tweet sentiment (positive, negative, or neutral) through Natural Language Processing (NLP). This integration enhances understanding of market sentiment's impact on cryptocurrency prices: positive sentiment may drive prices up, negative sentiment may lead to declines, and neutral sentiment may indicate stability. By analyzing sentiment alongside historical trends and emerging patterns, users gain a holistic view of cryptocurrency markets. This approach aids decision-making, improving transaction accuracy and efficiency. Ultimately, the combination of sentiment analysis with BiLSTM and BiGRU models advances the comprehension of cryptocurrency market dynamics, enhancing user insights and facilitating informed decisions in the volatile cryptocurrency ecosystem.

Spatio-temporal dynamic analysis of greenness base on NDVI equation for change detection from 2004 to 2024 at River Nile State, Atbara City, Sudan by using remote sensing and geographical information system

Urban regions' ability to maintain high environmental standards is largely dependent on their vegetation. A decrease in the amount of vegetated area on land has resulted from city expansion and population growth. An examination of land cover change in urban settings is necessary, particularly for urban regional planning that takes green, open space into account. The purpose of this study was to examine changes in urban vegetation cover in two Medan sub-districts from 2004 to 2014. Change analysis and the Normalized Difference Vegetation Index (NDVI) were performed in the study. The range of plant diversity in these locations was Observed. The results showed changes in vegetation cover areas in the mentioned years. In 2004, most of the areas were under a highly dense vegetation class while in 2014, they were under a low-density vegetation class with new sub-class. This indicates a decrease in vegetation cover due to changes to non-vegetation cover or land cover areas with less vegetation.

Multi-view 3D reconstruction of seedling using 2D image contour

3D reconstruction of seedling can provide comprehensive and quantitative spatial structure information, offering an effective digital tool for breeding research. However, accurate and efficient reconstruction of seedling is still a challenging work due to limited performance of depth sensor for seedling with small-size stem and unavoidable error for multi-view point cloud registration. Therefore, in this paper, we propose an accurate multi-view 3D reconstruction method for seedling using 2D image contour to constrain 3D point cloud. The rotation axis is calibrated and optimised by minimising point-to-contour distance between 2D image contour and projected exterior points from 3D point cloud. Then, to remove outliers and noise, we introduce the seedling mask of 2D image to constrained and delete projected outlier points of 3D model from corresponding view. Furthermore, we propose a residual-guided method to recognise missing region for 3D model and complete 3D model of small-size stem. Finally, we can obtain an accurate 3D model of seedling. The reconstruction accuracy is evaluated by average distance between projected contour of 3D model and 2D image contour of all views (0.3185 mm). Then, the phenotypic parameters were calculated from 3D model and the results are close to manual measurements (Plant height: R2 = 0.98, RMSE = 2.3 mm, rRMSE = 1.52%; Petioles inclination angle: R2 = 0.99, RMSE = 0.73°, rRMSE = 1.41%; Leaf area: R2 = 0.66, RMSE = 1.05 cm2, rRMSE = 7.63%; Leaf inclination angle: R2 = 0.99, RMSE = 1.01°, rRMSE = 1.72%; Stem diameter: R2 = 0.95, RMSE = 0.12 mm, rRMSE = 5.43%). Breeders can improve the selection of more resilient varieties and cultivars to different growing conditions starting from the dynamic analysis of their phenotype.

Seismic Fragility and Reliability of Base-Isolated Structures with Regard to Superstructure Ductility and Isolator Displacement Considering Degrading Behavior

ABSTRACT The present study investigates the effects of the degradation of mechanical properties (pinching, stiffness degradation, and strength degradation) in load-deformation relationship of the superstructures equipped with friction pendulum systems on the seismic fragility and reliability results. An equivalent two-degree-of-freedom model is employed, in which the Bouc-Wen hysteretic model characterizes the inelastic behavior of both the superstructure and the isolator. To examine a wide variety of system combinations with different structural properties and degradation severity, a comprehensive parametric study is performed. Incremental dynamic analyses are carried out to develop fragility functions. Subsequently, the seismic reliability of both the superstructure and the isolation level is assessed. Results indicate that the negative effects of degrading behavior are more prominent in stiff superstructures as it significantly decreases structural capacity and reliability indices. It is demonstrated that the system is primarily influenced by pinching behavior rather than degradation in strength and stiffness, especially at low intensity levels that correspond to lower limit-states. In the majority of investigated systems, the seismic demand in the isolator decreases when superstructures undergo degrading behavior. Overall, such effects should be considered in the reliability-based design procedure to attain design consistency in terms of reliability. The results of this paper that account for the degrading effects enable reliable estimations of key parameters essential for the design of the superstructure and the isolator.

Dynamic analysis and application of a stochastic rumor spreading model with education and punishment age under generalized nonlinear incidence on homogeneous networks

Dynamic analysis and application of a stochastic rumor spreading model with education and punishment age under generalized nonlinear incidence on homogeneous networks

Strong influence of magnetic field and non-uniform stress on elastic modulus and transition temperatures of twinned Ni–Fe(Co)–Ga alloy

The magnetization value and electric resistivity of the single-crystalline sample of Ni50Fe19Co4Ga27 shape memory alloy were measured. The elastic modulus was determined by the Dynamic Mechanical Analysis (DMA). The characteristic temperatures of martensitic transformation (MT) of the alloy were estimated from the temperature dependences of magnetization, electric resistivity and elastic modulus. A significant disparity between MT temperatures resulting from DMA and those estimated from magnetic and resistivity measurements was discovered. It was argued that the discrepancy is caused by the non-uniform mechanical stressing of twinned single crystal by the DMA analyzer. Moreover, the DMA measurements revealed a significant decrease of the elastic modulus of twinned martensite under the applied magnetic field of 1.5 kOe. To explain this effect, the temperature-dependent Young’s modulus of twinned crystal lattice was computed. The computations showed that the experimentally observed field-induced change of the elastic modulus is caused by the stress-assisted detwinning of the crystal lattice by the applied magnetic field.

Improvement of thermostability by increasing rigidity in the finger regions and flexibility in the catalytic pocket area of Pseudoalteromonas porphyrae κ-carrageenase.

Poor thermostability reduces the industrial application value of κ-carrageenase. In this study, the PoPMuSiC algorithm combined with site-directed mutagenesis was applied to improve the thermostability of the alkaline κ-carrageenase from Pseudoalteromonas porphyrae. The mutant E154A with improved thermal stability was successfully obtained using this strategy after screening seven rationally designed mutants. Compared with the wild-type κ-carrageenase (WT), E154A improved the activity by 29.4% and the residual activity by 51.6% after treatment at 50°C for 30min. The melting temperature (Tm) values determined by circular dichroism were 66.4°C and 64.6°C for E154A and WT, respectively. Molecular dynamics simulation analysis of κ-carrageenase showed that the flexibility decreased within the finger regions (including F1, F2, F3, F5 and F6) and the flexibility improved in the catalytic pocket area of the mutant E154A. The catalytic tunnel dynamic simulation analysis revealed that E154A led to enlarged catalytic tunnel volume and increased rigidity of the enzyme-substrate complex. The increasing rigidity within the finger regions and more flexible catalytic pocket of P. porphyrae κ-carrageenase might be a significant factor for improvement of the thermostability of the mutant κ-carrageenase E154A. The proposed rational design strategy could be applied to improve the enzyme kinetic stability of other industrial enzymes. Moreover, the hydrolysates of κ-carrageenan digested by the mutant E154A demonstrated increased scavenging activities against hydroxyl (OH) radicals and 2,2'-azinobis(3-ethylbenzothiazoline)-6-sulfonic acid (ABTS) radicals compared with the undigested κ-carrageenan.

A low-mass sub-Neptune planet transiting the bright active star HD 73344

Planets with radii of between $2$ and $4 R_ closely orbiting solar-type stars are of significant importance for studying the transition from rocky to giant planets, and are prime targets for atmospheric characterization by missions such as JWST and ARIEL. Unfortunately, only a handful of examples with precise mass measurements are known to orbit bright stars. Our goal is to determine the mass of a transiting planet around the very bright F6 star HD 73344 (Vmag=6.9). This star exhibits high activity and has a rotation period that is close to the orbital period of the planet ($P_ b =15.6$ days). The transiting planet, initially a K2 candidate, is confirmed through TESS observations (TOI 5140.01). We refined its parameters using TESS data and rule out a false positive with Spitzer observations. We analyzed high-precision radial velocity (RV) data from the SOPHIE and HIRES spectrographs. We conducted separate and joint analyses of K2, TESS, SOPHIE, and HIRES data using the PASTIS software. Given the star's early type and high activity, we used a novel observing strategy, targeting the star at high cadence for two consecutive nights with SOPHIE to understand the short-term stellar variability. We modeled stellar noise with two Gaussian processes: one for rotationally modulated stellar processes, and one for short-term stellar variability. High-cadence RV observations provide better constraints on stellar variability and precise orbital parameters for the transiting planet: a radius of $R_ b R_ and a mass of $M_ b M_ (upper-limit at $3 is $<10.48 M_ oplus$) . The derived mean density suggests a sub-Neptune-type composition, but uncertainties in the planet's mass prevent a detailed characterization. In addition, we find a periodic signal in the RV data that we attribute to the signature of a nontransiting exoplanet, without totally excluding the possibility of a nonplanetary origin. This planetary candidate would have a minimum mass of about $M_ c i_ c M_ and a period of $P_ c $ days. Dynamical analyses confirm the stability of the two-planet system and provide constraints on the inclination of the candidate planet; these findings favor a near-coplanar system. While the transiting planet orbits the bright star at a short period, stellar activity prevented us from precise mass measurements despite intensive RV follow-up. Long-term RV tracking of this planet could improve this measurement, as well as our understanding of the activity of the host star. The latter will be essential if we are to characterize the atmosphere of planets around F-type stars using transmission spectroscopy.

Seismic hazard study for the duration of ground-motions triggered by intraslab earthquakes

AbstractThis paper presents a probabilistic seismic hazard analysis for the duration of ground motions in Mexico City caused by intraslab earthquakes. The study implies establishing criteria to measure the duration of ground motions and developing predictive equations (GMPEs) for its estimation. Focus is placed on the relative significant duration, $$D_{Sr}$$ D Sr , which is based on the accumulation of energy of ground motions. The study extends to the development of hazard curves that allow estimating the annual probability of exceedance of said parameter. The scope is limited to ground motions caused by intraslab earthquakes occurring in Mexico and that engineeringly affect its capital, Mexico City, which is in a geographical region where the effects of soil-dynamic amplification are manifested considerably. A strong-motion database that includes 1517 horizontal accelerograms, with peak ground acceleration, $$PGA$$ PGA , greater than or equal to 3 cm/s2, recorded during 21 earthquakes from 1994 to 2023 were used to develop the GMPEs. The quantitative description of the time, size, and spatial distribution of the seismic-activity occurrence was defined using a catalog of 46 earthquakes that occurred from 1900 to 2023. The earthquakes have moment magnitude, $$M_{w}$$ M w , greater than or equal to 6. With the tools developed, amplitude- and duration-based hazard-consistent accelerograms can be simulated and used in nonlinear dynamic analyses (NDAs) of structures. This study includes an application example where three sites in Mexico City are selected to compute inelastic response spectra. Hysteretic-energy demands up to 5 times higher are found after a comparison between the inelastic-response spectra from hazard-consistent accelerograms and those provided by current Mexican regulations.

Deformation Characteristics and Activation Dynamics of the Xiaomojiu Landslide in the Upper Jinsha River Basin Revealed by Multi-Track InSAR Analysis

The upper Jinsha River, located in a high-mountain gorge with complex geological features, is highly prone to large-scale landslides, which could result in the formation of dammed lakes. Analyzing the movement characteristics of the typical Xiaomojiu landslide in this area contributes to a better understanding of the dynamics of landslides in the region, which is of great significance for landslide risk prediction and analysis. True displacement data on the surface of landslides are crucial for understanding the morphological changes in landslides, providing fundamental parameters for dynamic analysis and risk assessment. This study proposes a method for calculating the actual deformation of landslide bodies based on multi-track Interferometric Synthetic Aperture Radar (InSAR) deformation data. It iteratively solves for the optimal true deformation vector of the landslide on a per-pixel basis under a least-squares constraint based on the assumption of consistent displacement direction among adjacent points on the landslide surface. Using multi-track Sentinel data from 2017 to 2023, the line of sight (LOS) accumulative de-formation of the Xiaomojiu landslide was obtained, with a maximum LOS deformation of −126 mm/year. The true surface displacement of the Xiaomojiu landslide after activation was calculated using LOS deformation. The development of two rotational sub-slipping zones on the landslide body is inferred based on the distribution of actual displacements along the central profile line. Analysis of temporal changes in water body area data revealed that the Xiaomojiu landslide was activated after a barrier lake event and continuously moved due to the influence of higher water levels’ in the river channel. In conclusion, the proposed method can be applied to calculate the true surface displacement of landslides with complex mechanisms for analyzing the movement status of landslide bodies. Furthermore, the spatiotemporal analysis of the Xiaomojiu landslide characteristics can support analyzing the mechanisms of similar landslides in the Jinsha River Basin.