Internal Behavior Research Articles

Mass transfer and mixing performance in jet-to-counterflow micromixer

As an important component of the fine organic microreaction system, micromixers can realize efficient mixing of different fluids within a short distance. In spite of great progress in micromixer design for high mixing performance over the last decade, micromixers are limited by the narrowness of channels, making it impossible to operate at high throughputs. Here, we propose a novel jet-to-counterflow (JTC) micromixer, which is based on the offset fluctuation jet mechanism to build a jet-to-counterflow zone and an annular liquid film zone to promote the rapid and efficient mixing of fluids. Micro-PIV and dye visualization experiments are used to investigate the internal flow behaviors and mixing performance of the JTC micromixer. The results show that in the “jet-to-counterflow mixing zone”, the jet undergoes the transition of three flow regimes i.e. “no offset jet − stable offset jet − fluctuating offset jet” with the increase of Re under the effects of wall effect and fluid inertia. When Re = 100, the fluctuating offset jet enhances the internal perturbation, which promotes the mixing index of the micromixer within 3 mm up to 78 %. In addition, the fluctuating offset jet intensifies the disturbance of the fluid flow in the annular liquid film zone, which further enhances the fluid mixing. A mixing efficiency of 97 % is achieved in mixing experiments over flow rates ranging from 0.075 – 37.66 mL/min−1. Our results demonstrate that fluctuating offset jet can be used to enhance microfluidic internal perturbation and mixing, which provide new insights into the design of novel micromixers.

Phase transition and internal friction behaviors in Mn-doped Co-V-Ga shape memory alloys

Shape memory alloys with a high abundance of mobile interfaces exhibit remarkable internal friction (IF) behaviors, which can be utilized for the reduction of noise and vibration. In this study, we systematically investigate the martensitic transformation and internal friction behaviors in the Mn-doped Co53V35–xGa12Mnx (x = 0 - 10) polycrystalline alloys. Our findings indicate that using Mn to replace V results in decreased transformation temperatures but increased thermal hysteresis. The addition of Mn enhances magnetic exchange interaction, leading to a gradual enhancement in magnetization difference across martensitic transformation, thereby compromising the transformation entropy change and arresting the martensitic transformation. At a frequency of 0.4 Hz, the intensity of transformation IF peak is enhanced from 0.124 to 0.178 with increasing the Mn content from 0 to 4.5 %, as a result of deteriorated geometrical compatibility between austenite and martensite due to the addition of Mn. Furthermore, hydrogenation treatments substantially improve both the peak intensity and frequency dependence of peak position for the relaxation-type IF, demonstrating the great contribution from hydrogen-twin boundary interaction.

Optoelectronic synapses with chemical-electric behaviors in gallium nitride semiconductors for biorealistic neuromorphic functionality

Optoelectronic synapses, leveraging the integration of classic photo-electric effect with synaptic plasticity, are emerging as building blocks for artificial vision and photonic neuromorphic computing. However, the fundamental working principles of most optoelectronic synapses mainly rely on physical behaviors while missing chemical-electric synaptic processes critical for mimicking biorealistic neuromorphic functionality. Herein, we report a photoelectrochemical synaptic device based on p-AlGaN/n-GaN semiconductor nanowires to incorporate chemical-electric synaptic behaviors into optoelectronic synapses, demonstrating unparalleled dual-modal plasticity and chemically-regulated neuromorphic functions through the interplay of internal photo-electric and external electrolyte-mediated chemical-electric processes. Electrical modulation by implementing closed or open-circuit enables switching of optoelectronic synaptic operation between short-term and long-term plasticity. Furthermore, inspired by transmembrane receptors that connect extracellular and intracellular events, synaptic responses can also be effectively amplified by applying chemical modifications to nanowire surfaces, which tune external and internal charge behaviors. Notably, under varied external electrolyte environments (ion/molecule species and concentrations), our device successfully mimics chemically-regulated synaptic activities and emulates intricate oxidative stress-induced biological phenomena. Essentially, we demonstrate that through the nanowire photoelectrochemical synapse configuration, optoelectronic synapses can be incorporated with chemical-electric behaviors to bridge the gap between classic optoelectronic synapses and biological synapses, providing a promising platform for multifunctional neuromorphic applications.

Optimization of personnel evacuation routes for sudden nuclear accidents based on hybrid genetic-grey wolf optimizer algorithm

To address the emergency situation resulting from a sudden nuclear accident, it is imperative to develop an optimal emergency response plan that ensures the prompt and safe evacuation of affected individuals from the hazardous area.The paper proposed the hybrid genetic-grey wolf optimizer algorithm (GA-GWO).This algorithm integrated radiation environment and road network to plan evacuation paths that minimizes the radiation dose. This algorithm enhanced the convergence and search capabilities of the genetic algorithm (GA) by incorporating wolf pack characteristics and internal competitive behavior. This improvement allowed for more efficient exploration of potential evacuation routes. The feasibility of GA-GWO was validated through a visualization simulation utilizing Web Geographic Information Systems (WebGIS). The findings indicated that GA-GWO generated evacuation paths that minimize radiation dose, providing safe routes for the affected population. This approach demonstrates significant potential for application in emergency response planning for sudden nuclear accidents, ensuring both prompt and safe evacuations.

Non-invasive measurement of wall shear stress in microfluidic chip for osteoblast cell culture using improved depth estimation of defocus particle tracking method.

The development of a non-invasive method for measuring the internal fluid behavior and dynamics of microchannels in microfluidics poses critical challenges to biological research, such as understanding the impact of wall shear stress (WSS) in the growth of a bone-forming osteoblast. This study used the General Defocus Particle Tracking (GDPT) technique to develop a non-invasive method for quantifying the fluid velocity profile and calculated the WSS within a microfluidic chip. The GDPT estimates particle motion in a three-dimensional space by analyzing two-dimensional images and video captured using a single camera. However, without a lens to introduce aberration, GDPT is prone to error in estimating the displacement direction for out-of-focus particles, and without knowing the exact refractive indices, the scaling from estimated values to physical units is inaccurate. The proposed approach addresses both challenges by using theoretical knowledge on laminar flow and integrating results obtained from multiple analyses. The proposed approach was validated using computational fluid dynamics (CFD) simulations and experimental video of a microfluidic chip that can generate different WSS levels under steady-state flow conditions. By comparing the CFD and GDPT velocity profiles, it was found that the Mean Pearson Correlation Coefficient is 0.77 (max = 0.90) and the Mean Intraclass Correlation Coefficient is 0.66 (max = 0.82). The densitometry analysis of osteoblast cells cultured on the designed microfluidic chip for four days revealed that the cell proliferation rate correlates positively with the measured WSS values. The proposed analysis can be applied to quantify the laminar flow in microfluidic chip experiments without specialized equipment.

Internal Electrostatic Discharge Modeling: Validation and Fitting Using Tests on Insulated Wires

Electron beam tests were conducted to observe the internal electrostatic discharge behavior of four wire samples arcing into three termination resistors. The charging environment during the test was also simulated using 3-D NUMIT to calculate the expected voltage development within each wire. The impedances of the wires and the test setup were measured and included in a circuit model of the discharging wire connected to the measurement circuit. The circuit model was fit to the largest discharge observed on a 50 Ω load. The circuit model was then used to simulate discharges into 5 kΩ and 10 MΩ terminations, and the simulated pulses were compared to observed pulses on those terminations. Simulated peak voltages agree with observed voltages to within a factor of 1.6 and simulated decay times agree with observed decay times to within a factor of 2.3. For large pulses, derived source voltages range from 3.7 to 15.5 kV, derived source capacitances range from 4 to 11 pF, and derived source resistances range from 1100 to 3500 Ω.

Investigating the internal erosion behavior and microscopic mechanisms of chemically stabilized soil: an experimental study

IntroductionInternal erosion triggered by water pipeline leaks seriously threatens the stability of the urban ground. Hangzhou, a city in Zhejiang Province, China, is facing critical challenges due to urban ground collapse (UGC) caused by internal erosion. However, there is a lack of research on the prevention of UGC by improving the internal erodibility of underground soil. Addressing this issue is of utmost importance to ensure the city’s stability and safety. This paper proposes to improve the internal erodibility of typical sandy silt soils with chemical stabilisers.MethodsThe effects of three chemical stabilisers, lignosulphonate (LS), lime (LI), and lignin fibre (LF), on the critical shear stress (τc) and erosion coefficient (kd) of sandy silt soils were investigated, which from Hangzhou, Zhejiang, China, by the hole erosion test (HET) at different mixing amounts and at different conservation times.ResultsThe findings indicate that LF mainly improves the erosion resistance of sandy silt by increasing τc, and the maximum increase is 2.38 times; LI mainly improves the erosion resistance by decreasing kd, and the maximum decrease is 2.18 times. After adding LS, τc and kd did not change significantly. The scanning electron microscope (SEM) test revealed that the inclusion of LF led to the formation of larger agglomerates in the sandy silt soil. The microstructure of sandy silt soil remained dispersed even after adding LS. Various chemical stabilisers used to improve sandy silt soils exhibited distinct erosion mechanisms. Sandy silt soils improved with LF exfoliated into agglomerates, displaying high resistance to erosion. On the other hand, the sandy silt treated with LF still lacks a protective layer and shows minimal improvements in its ability to withstand erosion. In contrast, the LS-amended sandy silt remains stripped with individual soil particles with insignificant changes in erosion resistance.DiscussionThis study can provide a conceptual framework for choosing foundation treatment techniques in future urban development projects.

A study of fine-scale low-temperature cracking in geopolymer grouted porous asphalt mixtures based on real aggregate profile modeling

At a micro-scale level, grouted porous asphalt mixtures are multiphase composites consisting of aggregates, asphalt mortar, filler, asphalt mortar-aggregate interfacial transition zone, and asphalt mortar-filler interfacial transition zone. It exhibits different mechanical behavior under different temperatures and loading conditions. Compared with aggregate, asphalt mortar, and filler, the interfacial transition zone (ITZ) is more prone to damage at low temperatures, with both the fine structure and the nature of the contact interface having a significant effect on the overall strength and crack resistance of the material. To evaluate the influence of ITZ and filler material properties on the cracking resistance of the material, a grouted porous asphalt mixture model based on the real aggregate shape was established using finite element modeling. A cohesive zone model (CZM) was employed to characterize the internal mechanical behavior of the material, and a mesoscale damage simulation was performed for the grouted asphalt mixture. The study revealed the influence of different interfacial and filler material properties on the low temperature cracking resistance and proposed a design approach for anti-cracking grouted asphalt mixtures. The findings indicated that interfacial transition zone (ITZ) and filler properties play a crucial role on determining the damage characteristics. Increasing the ITZ and filler properties significantly enhanced the low temperature crack resistance of the grouted asphalt mixture.

Increasing parameter identifiability through clustered time-varying sensitivity analysis

Hydrological models are becoming progressively complex, leading to unclear internal model behavior, increasing uncertainty, and the risk of equifinality. Accordingly, our study provided a research framework based on global sensitivity analysis, aiming at unraveling the process-level behavior of high-complexity models, teasing out the main information, and ultimately exploiting its usage for model parameterization. The Distributed Hydrology-Soil-Vegetation Model implemented in a mountainous watershed was used. Results indicated that 5 soil parameters and 5 vegetation parameters were most important to control the streamflow responses, while their importance varied greatly throughout the simulation period. Four typical patterns of parameter importance corresponding to different watershed conditions (i.e., flood, short dry-to-wet, fast recession, and continuous dry periods) were successfully distinguished. Using this clustered information, parameters with short dominance times were more identifiable over the clusters (time periods) in which they were most important. The reduced posterior parameter space also slightly improved the model performance.

The mediating role of health behaviors in the relationship between internal locus of control and life satisfaction in public health students

Well-being is a continuous process requiring decisions and actions to maintain or build health. This study examines the indirect effect of health locus of control on life satisfaction via healthy behaviors based on living systems theory. Participants were 730 students of various majors related to medicine and health, aged between 19 and 30 (M = 22.29, SD = 1.64), including 79.04% women. Self-report measures were used to assess life satisfaction, multidimensional health locus of control, and health behavior. Women scored higher than men on the total health behavior scale, especially in a healthy diet and preventive behavior. Men scored higher than women on internal health locus of control (HLC), while women scored higher than men on the powerful others HLC in making decisions about their health. The study confirmed the mediating effect of healthy behavior on the relationship between the internal HLC and life satisfaction. The present mechanism highlights the crucial role of internal motivation in increasing subjective well-being by maintaining health behaviors among young adults. The role of intervention programs focused on improving internal HLC and health behaviors is discussed.

The Molecular Substrates of Insect Eusociality.

The evolution of eusociality in Hymenoptera-encompassing bees, ants, and wasps-is characterized by multiple gains and losses of social living, making this group a prime model to understand the mechanisms that underlie social behavior and social complexity. Our review synthesizes insights into the evolutionary history and molecular basis of eusociality. We examine new evidence for key evolutionary hypotheses and molecular pathways that regulate social behaviors, highlighting convergent evolution on a shared molecular toolkit that includes the insulin/insulin-like growth factor signaling (IIS) and target of rapamycin (TOR) pathways, juvenile hormone and ecdysteroid signaling, and epigenetic regulation. We emphasize how the crosstalk among these nutrient-sensing and endocrine signaling pathways enables social insects to integrate external environmental stimuli, including social cues, with internal physiology and behavior. We argue that examining these pathways as an integrated regulatory circuit and exploring how the regulatory architecture of this circuit evolves alongside eusociality can open the door to understanding the origin of the complex life histories and behaviors of this group.

Analysis of internal behavior of electrochemical hydrogen compressors at high pressures

We examined the internal behavior of an electrochemical hydrogen compressor under high-pressure conditions. In doing so, we focused on the changes in compressor efficiency and power consumption in response to intensified hydrogen back-diffusion under high pressures and various values of other parameters. First, as the operating temperature increased, the power consumed to achieve the same pressure ratio increased. This increased in power consumption was attributed to the fact that as the temperature increased, hydrogen back-diffusion intensified, which necessitated a net forward flux and induced flow losses. Second, as the relative humidity increased, power consumption decreased, and compressor efficiency increased. Although higher relative humidity intensifies back-diffusion, leading to flow losses, the accompanying significant decrease in ohmic losses increases compressor efficiency. By adjusting factors such as temperature and relative humidity, compressor efficiency can potentially be increased by up to 1.78 times. At high pressure ratios, hydrogen back-diffusion was inherently strong, and it became stronger at higher temperatures and relative humidities. Therefore, the compressor was more efficient when it was operated at lower temperatures and higher relative humidities. At the optimal operating temperature of 50 °C and 100 % relative humidity, the compressor efficiency peaked at 97.507 % when the pressure ratio was 100.

Dynamic data reconciliation based on elman neural network and particle filter

In the process of modern industries, complex nonlinear dynamic systems present high requirements for measured data. In the actual industrial process system, the measurement data obtained by sensors will inevitably be subject to noise disturbances from the equipment itself or from the outside environment. These noise disturbances will deteriorate the dynamic performance of the system to a certain extent and affect the industrial production. Particle filter (PF) can be used to infer the accurate outputs of nonlinear dynamic system from the contaminated measurement data, but PF is limited to the pre-known state space model. In the actual industrial process, it is difficult to summarize the internal behavior of the system and obtain the pre-known state space model. Therefore, it is impossible to directly use PF in the nonlinear dynamic system with unknown model. In order to solve the above problems, this paper proposes a dynamic data reconciliation method called ENN-PF, which combines Elman neural network (ENN) data-driven modeling with PF. In this method, ENN is used for data-driven modeling, that is, the system model is dynamically identified by using the input and output data of the system, and then the dynamic data reconciliation is carried out by using PF according to the model identified by ENN. Finally, the proposed ENN-PF method is validated by simulations and practical experiments to effectively reduce the interference of measurement noise and improve the dynamic performance of the system.

Study on high temperature evolution of pore structure and permeability characteristics of C/SiC composites based on in-situ X-ray computed tomography

Ceramic matrix composites (CMC) possess numerous distributed pore structures created during manufacturing, which can function as microchannels for fluid flow. This study examines the internal pores evolution process of C/SiC composites through in-situ X-ray computed tomography at varying temperatures. Visualize and analyze the three-dimensional geometric morphology and evolution behavior of composite materials at various temperatures through CT image reconstruction. Simultaneously, the pore network model was employed to model the microchannel structure of composite materials at different temperatures, extracting material pore characteristic parameters. The results suggest a close relationship between the mechanical properties of samples at different temperatures and their internal evolution behavior. The pore network model can identify the material's pore characteristic parameters and forecast the evolution trend of its permeability characteristics at varying temperatures.

How do corporate social responsibility perceptions facilitate advocacy behavior? The roles of organizational pride and responsible leadership

As a voluntary behavior, employees’ advocacy can enhance organizations’ competitive advantage and reputation. Drawing on social identity theory, this study explores the mechanism of by which corporate social responsibility (CSR) perceptions influence employee advocacy behavior using a sample of 333 two-stage data. The results show that internal and external CSR perceptions have positive effects on employee advocacy behavior, organizational pride mediating the relationships between internal and external CSR perceptions and employee advocacy behavior. Responsible leadership strengthens the effects of internal and external CSR perceptions on organizational pride, as well as the indirect effects of organizational pride on the relationships between internal and external CSR perceptions and advocacy behavior. This study investigates how micro CSR affects advocacy behavior by introducing organizational pride and responsible leadership, thus advancing the micro CSR literature and providing directions for micro-level CSR research. The findings of this research provide guidance to managers by focusing on employee perceptions of CSR activities and organizational pride and by cultivating responsible leadership.

Warming planet and expanding wallets: Climate risk and managerial moral hazard

As global climate change intensifies, its potential risks have captured international scrutiny. This paper systematically analyzes the relationship and influence mechanism between climate risk and managerial self-interested behavior by constructing the PSR (Pressure-State-Response) model and the theoretical framework of internal and external perspectives of agency theory. The results of empirical tests using a sample of Chinese listed companies from 2010 to 2020 reveal that there is a U-shaped relationship between climate risk and managerial self-interest, implying that this will intensify managerial self-interested behavior as climate risk continues to increase to a certain stage. We also identify management discretion and donation income as internal and external influencing mechanisms. In addition, this U-shaped relationship is particularly significant in non-state-owned firms as well as in the non-energy sector. Overall, our study provides new theoretical and empirical insights into the relationship between climate risk and internal managerial behaviors of firms, and it also has important implications for both firm practice and policy making.

How do ESG controversies moderate the nexus between ESG performance and cost of capital? Evidence from European listed companies

PurposeThis study aims to investigate the effect of ESG controversies and their moderating role in ESG performance and the cost of equity and overall, short-term and long-term debt capital relationship in European listed companies.Design/methodology/approachThe study employs two-way fixed effects panel linear regression models on the balanced longitudinal dataset of 231 European non-financial companies listed in the MSCI Europe Index in 2017–2022. To check the robustness, the study utilises the fixed effects logistic regression models with heteroskedasticity-consistent standard errors.FindingsThe study reveals the significant effect of ESG performance (negative) and ESG controversies (negative) on the cost of debt capital and the substantial moderating effect of ESG controversies (positive). Additionally, it provides empirical evidence of the crossover moderating effect of ESG controversies in ESG performance and cost of equity relationship.Research limitations/implicationsThe findings contribute to corporate practice and empirically support legitimacy and stakeholder theories.Practical implicationsCompanies can utilise the results to proactively enhance their internal policies and behaviour to align with ESG practices and avoid ESG controversies, which will translate into reduced equity capital costs for shareholders and a lower cost of debt capital charged by creditors.Originality/valueTo the best of the authors’ knowledge, this is the first study to comprehensively investigate the influence of ESG controversies and their moderating effect in the context of the equity and debt capital cost for European listed companies.

Analysis of the effect of cavitation on internal fluid excitation characteristics of centrifugal pumps

To explore the influence of cavitation on the internal fluid excitation characteristics of pumps, numerical simulations and performance testing evaluations were performed on the IS65-50-125 centrifugal pump. The prototype pump's exterior characteristic and cavitation performance curves, as well as its bubble volume distribution, were successfully replicated using numerical computations. The effect of cavitation on the internal pressure pulsation characteristics of the centrifugal pump under various operating situations was comprehensively investigated, indicating a relationship between the degree of cavitation and the root mean square values of pressure pulsation. Special emphasis was placed on the changes in features at intermediate and high frequencies, as well as the processes of rising bubble volume and vortex shedding at the impeller trailing edge on pressure pulsation. To validate the simulation results, a centrifugal pump vibration and noise testing platform was built, and studies on vibration intensity and internal sound field noise were conducted. The experimental results revealed that the vibration intensity and internal sound field sound pressure level of the centrifugal pump rose as cavitation conditions deteriorated, confirming the modeling results. This study's significant innovation is the precise identification of the pump's performance changes under different operating conditions by monitoring pressure pulsation changes at various frequencies, as well as an in-depth discussion of the impact mechanism of cavitation phenomena on the internal fluid excitation behavior of centrifugal pumps. The study demonstrates differences in pressure pulsation characteristics on the suction and pressure sides under various cavitation situations, as well as the process of vortex creation and shedding generated by bubbles in the impeller input channel during severe cavitation. This gives new theoretical basis for pump vibration and noise reduction, as well as significant improvements in centrifugal pump performance and stability.

Visual depiction and numerical characterization of intricate flow in triply periodic minimal surface foams

Benefiting from the structural specificity and programmability, the bioinspired triply periodic minimal surfaces (TPMSs) bring excellent physicochemical properties that are distinct from conventional topologies. Especially with the rapid development of additive manufacturing and high-performance computing capacities, function-oriented design and synthesis of smart TPMS materials or devices have become feasible. Therefore, understanding the flow characterizations induced by TPMS foams is of remarkable importance to the successful design and practical operation. However, the in-depth studies and theoretical guidance on the relationship between structure and flow characterizations of TPMS foams are still limited. In this study, an Eulerian and Lagrangian coupled model is developed to investigate the internal flow behaviors and flow regime transition mechanism from creeping to inertial flow in four representative TPMS foams. The simulation accuracy is then validated by a high-resolution pore-scale flow field observation. Results show that the flow morphology and pressure drop characteristics are highly influenced by TPMS geometry and Re. Among which, Schwarz Diamond (D), Schoen Gyroid (G), and Fischer-Koch S (S) foams are more susceptible to radial flow disturbance, while Schoen inverted Weissenberg periodic foam to axial flow disturbance. In addition, higher porosities delay the transition to transitional regime of the flow. This work establishes firm theoretical and methodological foundations for the customization and intelligent development of bioinspired TPMS foam materials in broad fluidic applications.

Emotional Competences in Adolescents Exposed to Colombian Armed Conflict During Their Childhood

AbstractObjective: Analyse the mediation role of emotional competences on behavior problems in adolescents exposed to Armed-Conflict Childhood Adversities (ACCA). Method: Families with adolescent children who studied in three schools in the municipality of Soacha, Colombia, were invited to participate in the study. One hundred and sixty-one participants were selected and pooled into three groups according to their Adverse Childhood Experiences (ACE) scores: lower-ACE (LACE), higher-ACE (HACE), and ACCA using the Adverse Childhood Experiences Questionnaire for Adolescents (ACE-QA). The Emotion Recognition Task, the Empathy for Pain Task, and the Child Behavior Checklist assessed teenagers’ emotional functioning. Results: Teenagers exposed to ACCA more frequently experienced childhood adversities such as domestic violence, child abuse, and parental neglect. Moreover, these adolescents were less accurate in discriminating angry faces, reported higher control perception after social stressors, were more rigorous in punishing those who intentionally harmed others, and showed more internalizing behavior problems. In the mediational model, we found that: the control perception after social stress mediated the reduction of depressive symptoms in adolescents with ACCA history. Additionally, inaccuracy in perceiving angry faces and harsh punishment toward behaviors that intentionally harm others mediated the presence of thinking problems, anxiety, and rule-breaking behaviors. Conclusions: Colombian adolescents who experienced ACCA showed specific changes in their emotional competences, which mediate the parental report of behavioral problems. These results indicate the need for more focused interventions aimed at improving the emotional competences and mental health of adolescent victims of armed conflicts.