Influence Of Inertia Research Articles

Non-spherical drug particle deposition in human airway using computational fluid dynamics and discrete element method

Currently, the air pollution and the respiratory disease problems that affect human health are increasing rapidly. Hence, there is attention for trend prediction of the located deposition of inhaled particles. In this study, Weibel’s based human airway model (G0-G5) was employed. The computational fluid dynamics and discrete element method (CFD-DEM) simulation was successfully validated by comparison to the previous research studies. The CFD-DEM achieves a better balance between numerical accuracy and computational requirement when comparing with the other methods. Then, the model was used to analyze the non-spherical drug transport with different drug particle sizes, shapes, density, and concentrations. The results found that all the studied factors affected the drug deposition and particle out-mass percentage except the drug concentration. The drug deposition was increased with the increasing of particle size and particle density due to the influence of particle inertia. The Tomahawk-shaped drug deposited easier than the cylindrical drug shape because of the different drag behavior. For the effect of airway geometries, G0 was the maximum deposited zone and G3 was the minimum deposited zone. The boundary layer was found around bifurcation due to the shear force at the wall. Finally, the knowledge can give an essential recommendation for curing patients with pharmaceutical aerosol. The design suggestion of a proper drug delivery device can be summarized.

Unstable oscillatory flow of non-Brownian suspensions in Hele-Shaw cells

The behavior of neutrally buoyant, non-Brownian suspensions subject to square-wave flow oscillations in Hele-Shaw cells is investigated experimentally. The velocity field across the cell gap is determined by tracking particles in a plane parallel to the main flow. The suspension develops an instability characterized by the growth of a transverse velocity component that is periodic along the main flow direction and in time. No influence of inertia on the development of the instability was observed. The characteristic onset time varies as the inverse of the oscillation amplitude with particle volume fraction dependence similar to that of the shear-induced diffusivity across the cell aperture.

Influence of inertia on liquid splitting at fracture intersections

Liquid splitting behavior at fracture intersections is an important process affecting unsaturated flow in fractured rocks. The role of inertia in liquid splitting at a fracture intersection, however, remains poorly understood. In this study, a theoretical model considering inertia is proposed to explore the inertial effect on liquid splitting at idealized facture intersections consisting of a main fracture and a branch fracture. The liquid droplet splitting behaviors predicted by the proposed model are in good agreement with the carefully controlled visualization experiments. By comparing the model predictions with and without inertia and comparing with experimental data, we show that neglecting the inertial effect leads to underestimation of liquid partitioning into the branch fracture with a smaller aperture than the main fracture. Furthermore, a threshold droplet length is defined to quantify the droplet length at which the inertial effect starts to exert an impact on the splitting dynamics. The influence of key parameters, such as the inclination angle, the fracture apertures, and the dynamic contact angles, on the droplet splitting behaviors is investigated through a systematic parameter sensitivity analysis. We show that the inclination angle affects the threshold droplet length mainly by controlling the initial droplet velocity. It is also demonstrated that the fracture apertures and the advancing and receding contact angles have significant impact on the volume percentage partitioned into the branch fracture. The improved understanding in this work may provide new insights into unsaturated flow and contaminant transport behaviors in fractured networks with implications for hydrological and environmental applications.

Dynamic Frequency Performance Analysis and Improvement for Parallel VSG Systems Considering Virtual Inertia and Damping Coefficient

Parallel virtual synchronous generator (VSG) systems are emerging as an attractive solution for inertia support and frequency stability enhancement of the power grid. However, the dynamic frequency characteristic is more complicated due to the coupled interaction of line impedance, virtual inertia, and damping coefficient in parallel VSG systems. The problems for frequency stability, dynamic performance, and frequency/power oscillation have raised much more attention. In this article, a systematic analysis of the influence of virtual inertia and damping coefficient on the dynamic frequency characteristic among parallel VSG systems was presented, and a quantitative assessment for dynamic frequency performance based on the 2-norm <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\boldsymbol {\mathcal{ H}}_{2}$ </tex-math></inline-formula> was proposed. Furthermore, a coordinated control for virtual inertia and damping was proposed to improve frequency stability and achieve a better dynamic performance of parallel VSG systems. The effectiveness and superiority of the proposed method were verified by simulation and experimental results.

Stability behavior of load adjustment and primary frequency control of pumped storage power plant with upstream and downstream surge tanks

This paper studies the stability behavior of load adjustment and primary frequency control of pumped storage power plant (PSPP) with upstream and downstream surge tanks (UDST). Firstly, the model of PSPP with UDST under load adjustment and primary frequency control is established. The stable domains of PSPP with UDST under load adjustment and primary frequency control are determined. The influence of flow inertia and head losses of connecting pipes of UDST on stable domains is analyzed. The critical stable sectional areas (CSSAs) of UDST under load adjustment and primary frequency control are determined and analyzed. The results show that the stability of PSPP with UDST under load adjustment is usually better than that of PSPP with UDST under primary frequency control. Under load adjustment and primary frequency control, the flow inertia of connecting pipes of UDST is unfavorable for the stability of PSPP, while the head losses of connecting pipes of UDST have no impact on stability of PSPP. Under load adjustment, the CSSAs of UDST present a complex change rule in reference to different governor parameters. Under primary frequency control, the CSSAs of UDST present a monotonic change rule in reference to different governor parameters. With the rise of CSSAs of UDST, the stable domains under load adjustment and primary frequency control become larger.

Phase separation phenomenon in mixed system composed of low- and high-inertia active particles

Active matter refers to a class of substance capable of autonomously moving by harnessing energy from its surrounding environment. The substance exhibits unique non-equilibrium phenomenon, and hence has attracted great attention in the scientific community. Many active matters, such as bacteria, cells, micro-swimmers, and self-propelled colloidal particles, operate in viscous environments and their motions are described usually by using overdamped models. Examples include overdamped active Brownian particle (ABP) model for self-propelled colloidal particles in solution and run-and-tumble (RTP) model for swimming bacteria. In recent years, increasing studies focus on the influence of inertia on the behavior of active matter. Vibrating robots, runners, flying insects, and micro-fliers are typical of active systems under the underdamped condition. The motions of these active matters can be modelled by underdamped Langevin equation, known as the active inertial particle (AIP) model. Previous studies have demonstrated that like the scenarios in ABP systems, motility-induced phase separation (MIPS) phenomena also happen in AIP systems under certain density conditions. However, due to the strong collision-and-rebound effect, aggregation of AIP particles and hence the MIPS are impeded. In complex living/application environments, mixture of different active agents is often seen. Some studies on mixed systems of active matter show that the composition is an important quantity, which influences the phase separation phenomena. In this paper, we study the phase separation phenomena in a mixed system composed of low- and high-inertia active particles by underdamped Langevin dynamics simulations. We find that compared with single-component system, the mixed system is unexpectedly favorable for the occurrence of phase separation at a moderate overall concentration and a certain range of component fraction, while unfavorable for phase separation at a high overall concentration. The underlying mechanism is that the presence of a small number of the high-inertia particles could accelerate the motion of the low-inertia particles, thus facilitating their aggregation and promoting the phase separation. However, when the fraction of the high-inertia particles is large, frequent elastic collisions would disturb the aggregation of the low-inertia particles and suppress the occurrence of phase separation. Our results provide a new insight into the collective behavior of active materials and also a reference for their design and applications.

Novel effective room temperature-based predictive feedback control method for large-scale district heating substation

• A predictive feedback control strategy based on effective room temperature is proposed. • The feasibility of the method is verified using an existing district heating substation. • The proposed method is flexible and performs well in terms of anti-interference. • The proposed method can reduce thermal energy consumption by 6.1%. Conventional district heating (DH) substations in China use a feed-forward adjustment method that predicts the water supply temperature based on the outdoor temperature. This method does not consider the delay of the pipe network and the thermal inertia of the building. Most importantly, the lack of closed-loop feedback on the indoor temperature results in high energy consumption and large fluctuations in room temperature. In this study, a predictive feedback system based on effective temperature control has been proposed to improve the quality of district heating. First, a dynamic simulation control model of a DH substation was created based on measured data. Then, through dynamic simulation analysis, the influence of the heating network delay on the room temperature was observed to be smaller than the influence of the building's thermal inertia, which confirmed that predictive feedback control based on effective temperature could be achieved. Finally, the new control method was compared to two conventional control methods. Based on the comparison with the two conventional controls, refining the timespan of the feed-forward control was found to be ineffective for improving room temperature stability owing to thermal inertia. The new control method demonstrated high control flexibility and strong anti-interference, and the indoor temperature fluctuation decreased from ±1.1 °C to ±0.3 °C compared with conventional control methods. In this case, under the premise that thermal comfort is not affected, the room temperature setting can be reduced by 0.5 °C, resulting in an energy saving of 6.1%, with a payback return period of less than a year. This method only requires installing room temperature sensing equipment and linking the feedback control algorithm to the original control system and is therefore easy to achieve.

ПАРАДИГМА УПРАВЛІННЯ ЗМІНАМИ В КОНТЕКСТІ КАДРОВОГО МЕНЕДЖМЕНТУ

The article explores the change management process from the perspective of human resource management, taking into account the functioning peculiarities of modern organizations. The influence of organizational inertia on its adaptability to external and internal environment demands, as well as its ability to change, is identified. Based on organizational criteria, the impact of inertia on the speed of change for different organizations is determined. It is argued that organizational changes are complex, hard to predict, and somewhat conflicting processes, requiring the consideration of human resource management specifics. The study demonstrates that the human aspect plays a fundamental role in any change process, as the potential and interactions between employees and organizational leaders define the success of change implementation. Practical recommendations for enhancing the effectiveness of change components are provided using D. Gleicher's change formula. Typical mistakes in change implementation are detailed, and managerial approaches to prevent such symptoms are proposed. The most significant reasons inhibiting the achievement of personal goals by both managers and individual employee groups are identified. Approaches for more effective time utilization and the implementation of individual and team changes are suggested. The typology of employees concerning changes is analyzed, and utilizing practical results from the diffusion of innovation theory, appropriate managerial directions are identified to activate collective efforts towards change. The application possibilities of D. Kolb's four-stage learning cycle for engaging and implementing changes among various employee psychotypes are substantiated. The study concludes that different employee types exhibit different strengths and weaknesses, motivating and demotivating factors, as well as diverse needs and prospects for personal development. Considering distinctive characteristics, motivational and demotivating influences, and risk zones in professional activity, the main employee types are delineated, accompanied by recommendations to mitigate risk zones during their integration into the change process.

The Impact of Management Innovation, Organizational Inertia, and Organizational Learning on Organizational Performance: A Case Study of the Manufacturing Industry in the Yangtze River Delta Region of China

Enterprise innovation has always been a hot issue in enterprise development and theoretical research. China has now entered a new stage of development. The implementation of innovative strategies and the acceleration of the construction of an innovative country have made innovation even more critical to business operations and development. Technological limited resources of the enterprise and the uncertainty in the research and development process, the implementation of technological innovation will face great unknowns and challenges. The successful implementation of management innovation must effectively integrate the existing knowledge and resources of the enterprise. Organizational learning is the process of using existing resources and learning new knowledge. The development of management innovation will effectively promote the enterprise to carry out organizational learning. Only when the organic combination of management innovation and organizational learning is realized, can the organization’s competitive advantage be enhanced and the enterprise’s own performance improved. This study’s purpose is attempts to explore the relationship and provide data support for it, and then puts forward management suggestions for enterprises trying to improve organizational performance by implementing management innovation. After sorting out the relevant literature, for the research design, this study takes organizational learning as an intermediary variable and constructs a theoretical model among management innovation, organizational inertia, organizational learning, and organizational performance; uses SPSS and AMOS software to conduct an empirical test on the collected 2407 valid questionnaires. The findings and the conclusions are management innovation and organizational inertia influence organizational performance, and organizational learning has a mediating role. Finally, management suggestions are put forward for enterprises to improve organizational performance by implementing management innovation.

Probing the influence of inertia, viscosity, and initial offset on the hydrodynamic interaction of droplet pairs in confined shear flow

The collision behavior of droplet pairs subjected to confined shear flows at high density and viscosity ratios remains unexplored and unquantified, and therefore, the critical density and viscosity ratios for the collision mode of droplets under geometric parameters were unknown. Simulations have been performed using a free-energy-based lattice Boltzmann method, with the aim of determining new regimes compared to the previous study. The results demonstrate that the interaction between viscous and inertia forces plays a vital role in the coalescence nature of droplets, their deformation, course of trajectory, as well as their expedition toward the steady state.

Enhanced pinch flow fractionation using inertial streamline crossing

In this work, we study the influence of inertia on the dynamics of neutrally buoyant spherical microbeads of varying diameter in a pinch flow fractionation device. To that aim, we monitor their trajectory over an unprecedented wide range of flow rates and flow rate ratios. Our experimental results are supplemented by a depth-averaged 2D-model where the flow is described using the Navier-Stokes equation coupled with the shallow channel approximation and where particles trajectories are computed from Newton’s second law of motion with a particle tracing model. Above a certain flow rate, we show that particles inertia enables them to cross streamlines in response to an abrupt change of direction. These streamline crossing events combined with the increasing effect of the inertial lift forces drive particles to deviate from the inertialess trajectory. The amplitude of the resulting inertial deviation increases both with the particles diameter and the total flow rate before reaching a plateau. Consequently, based on our numerical and experimental results, we determine the optimal flow conditions to shift the particles distribution in order to significantly enhance their size-based separation.

Experimental study on dynamic tensile performance of Q345 structural steel considering thickness differences

This paper experimentally investigates the dynamic tensile performance of Q345 structural steel, especially taking the tested coupon thickness as the key parameter. The tests of low alloy Q345 structural steel widely used in China are carried out under intermediate strain rate level loading of 101s−1 to 102s−1, as well as under static loadings for comparison. A purpose-built experimental arrangement is set up for dynamical coupon test, which can convert the compression triggered by the impact hammesr into rapid tension action. Firstly, the reliability of the proposed experimental technique and measurement method is verified by evaluating the influence of inertia and stress wave propagation. Then, a detailed description of the test results concerning the effect of strain rates on steel material is provided, including failure modes, the yield strength, ultimate strength, elongation, and dynamic increase factors (DIF) of the specimens. Additionally, the results of previous tests on the dynamic properties of steel materials and their relationships to evaluate the validity of the test results are summarized and compared, and the levels and sources of DIF inconsistency are also discussed. Based on the test results, the modified Cowper-Symonds formula was proposed to predict the DIFy-ε̇ relationship curve of yield strength of Q345 steel considering the size effect. Meanwhile, the applicability of Malvar formula for predicting ultimate strength by DIFu-ε̇ relationship curve of Q345 steel with different sizes was verified.

Provision of Virtual Inertia Support Using Battery Energy Storage System

The paper presents the importance of the grid inertia constant for the frequency stability of the future high-res low-inertia power systems. Since more and more renewable energy sources (RES) are being connected to the power system via frequency converters, the grid inertia constant is reduced. This issue can be mitigated by applying appropriate control mechanisms through which RES can provide virtual inertia and provide rotating reserves for primary frequency control. The concept of a virtual synchronous generator for providing virtual inertia is elaborated, as a solution to the presented problems. By applying virtual synchronous generators, RES can provide support for frequency control during disturbances almost like conventional synchronous generators. The influence of virtual inertia on the stability of the Croatian power system was analyzed using a battery energy storage systems (BESS) with a control mechanism that enables its participation in frequency control.

Evaluation of Indoor Thermal Environments Using a Novel Predicted Mean Vote Model Based on Artificial Neural Networks

The assessment of indoor thermal environments is crucial to achieving thermal comfort and energy efficiency. However, the inaccurate evaluation and strong nonlinear variations of thermal comfort parameters limit engineering designs. Therefore, a coupled heat-transfer model was developed in this study, and large eddy simulations were performed to verify the influence of inertia and buoyancy—which are mutually exclusive forces but coexist in large-space building environments—on inhomogeneous thermal environments. Furthermore, an artificial neural network (ANN) model was designed to overcome the limitations of the nonlinear relationships between thermal parameters and predicted mean vote (PMV) values. PMV indexes can be predicted using the ANN model when thermal parameters are used as input data. Subsequently, a genetic algorithm, harmony search algorithm, gravitational search algorithm, and whale optimization algorithm were adopted to optimize the neural network structure to prevent its confinement in a local optimum. Finally, with 5000 data sets, the minimum-error neural network structure 6-22-23-1 of the ANN-GA neural network model had high prediction accuracy, mean relative error &lt; 1.38, root mean square error &lt; 1.34, and a regression coefficient of ~1. The proposed ANN model can help improve the assessment of the thermal environment and thermal comfort of buildings.

Experimental and numerical study of installing a dune model in a 90° bend in the horizontal-vertical pneumatic conveying system

In the pneumatic conveying process, particles move to the bend under the influence of inertia to form a particle rope, which will cause serious wear between the particles and the pipe wall, and then the dune model is designed and installed in the 90° bend to reduce energy consumption and wear in this study. Firstly, the minimum pressure drop velocity of particles transported by different size dune models was obtained through experimental study. Then the energy saving mechanism of the dune model is studied by CFD-DEM coupling. The experimental results show that the installation of the dune model reduces the minimum pressure drop velocity. The numerical simulation results show that the number of collisions between the particles and the tube wall in the vertical tube decreases after the installation of the dune model, which reduces the energy loss. Moreover, the increasing of tail size of the dune model is beneficial to the diffusion and acceleration of the particles in the vertical tube.

Influence of Inertia on the Dynamic Compressive Strength of Concrete.

The rate sensitivity of concrete material is closely related to the inertia and viscous effects. However, the effect of inertia on the dynamic strength of concrete remains unclear. In this paper, digital image correlation technology was applied to study the strain variation of dry and saturated concrete with different loading rates. The test results indicated that the strain gradually decreased with the distance from the load end, and the strain gradient around the load region increased with the strain rate, especially for saturated concrete. Then, a single degree of freedom model was established to evaluate the dynamic compressive strength of elastic concrete. The calculated results indicated that the influence of inertia on the dynamic increase factor (DIF) was negligible for concrete within a low strain rate. When the strain rate is larger than 100/s, the inertial effect on the strength of concrete should be considered. After that, a quasi-static concrete damaged plasticity (CDP) model was employed to simulate the influence of inertia on the stress distribution and axial reaction force at the loaded end of concrete under different rates of compressive loading and verified with experimental results. The results obtained in this study indicated that the dynamic nominal strength of concrete obtained from the tests could not be directly used for structural analysis which may overestimate the effect of inertia on the dynamic response of the structure.

Does Digital Inertia Matter? The Driver of Intentions in a Smart Senior Care Context

Aging is one of the trends of population, which may bring problems to the elderly individually, and financial, economic and social problems to the government. Therefore, how to solve or mitigate the impact of aging through the development of intelligent elderly services has become a major issue for the current government and academia. The purpose of this study is to explore the status and relationship of digital skills, attitude towards smart senior care service and behavioral intention of the elderly. The influence of digital inertia on the relationship between digital skills, attitudes and behavioral intention in the elderly. Data was collected by questionnaire survey and 403 valid samples were received. Findings show that positive impacts were confirmed among digital skills, attitude towards smart senior care service and behavioral intention of the elderly, while the moderating effect of digital inertia on those variables was not. Lastly, such a smart senior care service provider should gradually build a system of smart services, including hardware and software was suggested to the government departments, institutions of smart senior care service and follow-up studies.

USV path following controller based on DDPG with composite state-space and dynamic reward function

Reinforcement learning (RL) is suitable for the design of unmanned surface vessels (USV) path-following controllers for its model-free and unsupervised learning. However, the USV state transition is not strictly consistent with Markov properties and the state-space, action-space, reward function strongly affect the performance of the RL-based controller. According to the dynamics and kinematic characteristics of USV, we design a new state-space to reduce the influence of large inertia and state hysteresis on the RL agent training. A comprehensive reward function is proposed to avoid the RL-based controller falling into local optimum according to the task decomposing. A dynamic threshold is used in the reward function to accelerate the training speed while ensuring tracking accuracy. Finally, the effectiveness of the proposed RL-based controller is evaluated by means of simulation and actual USV path following.

Study of the influence of synthetic inertia on transient stability of electric power systems

Study of the influence of synthetic inertia on transient stability of electric power systems

Studying the Influence of Synthetic Inertia on Electric Power System Transient Stability

Development of wind power around the world is a promising solution to the energy crisis. In power systems with a predominant share of wind power plants connected through power converters, their influence on the power system dynamic properties becomes significant. One of the important problems is reduction of the power system total inertia. In view of this, grid operators place demands on connected wind power plants for active power control and participation in frequency control. One possible solution is using synthetic inertia in the wind power plant control system. Research activities in this field place focus on improving the frequency stability and coordinating the synthetic inertia controller with other wind power plant control systems. However, the influence of synthetic inertia and its tuning on the power system stability are still poorly studied. The paper analyzes the effect of synthetic inertia on the power system transient stability. It is shown that by adjusting the synthetic inertia parameters, it is possible not only to obtain the required inertial response, but also to increase the power system transient stability. The influence of the measurement time window and frequency variation rate calculation, which is important in certain modes, is also studied. The study results are obtained for test and real-scale power system configurations.