Passive State Research Articles

Passivity study of titanium alloy TA2 in simulated seawater solution

In the present work, we introduced a novel way to study the Tafel slope of titanium in passive state based on potentiodynamic test with a break by potentiostatic polarization. The power law model as well as surface analysis methods such as AES and XPS were also introduced to character the thickness and composition of the film. Results indicate that the Tafel slope of titanium electrode in the passive state increases with the applied overpotential. The anodizing constant is found to be equal to about 0.24–0.46 Å/s and 4–10 Å/V. The results showing highly consistent with AES and XPS results. The passive film are mainly composed of TiO2 predominantly outer layer, and titanium sub-oxide, Ti(OH)x predominantly inner layer.

Robust numerical solution for assessing corrosion of reinforced concrete structures under external power supply

Impressing current is a popular technique to adjust corrosion behaviors of structures, both in academic investigation and engineering practice. Focusing on the specific problem, this paper presents a robust solution strategy for analyzing corrosion of reinforced concrete structures, under both voltage-controlled and current-controlled power supply. Following fundamental electrochemistry, a nonlinear numerical model incorporating field and global variables is developed, where the ways of considering power supplies with different controlling modes are presented. To tackle the essential global variable to problems under current-controlled power supply, a pseudo discretization method is newly developed to facilitate the highly nonlinear finite element analysis. Given moisture-induced nonuniform concrete resistivity, the moisture field in concrete is also modelled and solved together with the corrosion propagation through a staggered solution scheme. The proposed approach is carefully validated against a variety of reported experiments. Moreover, by directly controlling steel passivation state, the influence of steel depassivation extent on the cathodic protection performance for aging reinforced concrete structures under different saturation degree is numerically investigated for the first time. It is discovered that the protection effectiveness is closely related to the steel depassivation state. It is also revealed that the influence of concrete saturation degree on protection performance in a current-controlled system is generally more complex than that of a voltage-controlled system.

Development and verification of a physiologically motivated internal controller for the open-source extended Hill-type muscle model in LS-DYNA

Nowadays, active human body models are becoming essential tools for the development of integrated occupant safety systems. However, their broad application in industry and research is limited due to the complexity of incorporated muscle controllers, the long simulation runtime, and the non-regular use of physiological motor control approaches. The purpose of this study is to address the challenges in all indicated directions by implementing a muscle controller with several physiologically inspired control strategies into an open-source extended Hill-type muscle model formulated as LS-DYNA user-defined umat41 subroutine written in the Fortran programming language. This results in increased usability, runtime performance and physiological accuracy compared to the standard muscle material existing in LS-DYNA. The proposed controller code is verified with extensive experimental data that include findings for arm muscles, the cervical spine region, and the whole body. Selected verification experiments cover three different muscle activation situations: (1) passive state, (2) open-loop and closed-loop muscle activation, and (3) reflexive behaviour. Two whole body finite element models, the 50th percentile female VIVA OpenHBM and the 50th percentile male THUMS v5, are used for simulations, complemented by the simplified arm model extracted from the 50th percentile male THUMS v3. The obtained results are evaluated additionally with the CORrelation and Analysis methodology and the mean squared error method, showing good to excellent biofidelity and sufficient agreement with the experimental data. It was shown additionally how the integrated controller allows simplified mimicking of the movements for similar musculoskeletal models using the parameters transfer method. Furthermore, the Hill-type muscle model presented in this paper shows better kinematic behaviour even in the passive case compared to the existing one in LS-DYNA due to its improved damping and elastic properties. These findings provide a solid evidence base motivating the application of the enhanced muscle material with the internal controller in future studies with Active Human Body Models under different loading conditions.

Determination of Passive Earth Pressure on a Cantilever Retaining Wall in a Narrow Foundation Pit Based on Logarithmic Spiral Sliding Surface

The distribution of passive earth pressure on a cantilever flexible retaining wall in a narrow foundation pit is significantly affected by the adjacent retaining wall and the width of the foundation pit. The deformation mode of the cantilever retaining wall rotating around the displacement zero point makes the soil layer below the displacement zero point retain a nonlimit passive state. The functional relationship between soil mechanical parameters and horizontal displacement in the nonlimit state region, considering the influence of displacement, is established. A new combined failure mode of the soil mass in the passive zone of the narrow foundation pit is proposed, which is the logarithmic spiral fracture surface in the nonlimit state region and the broken line fracture surface in the limit-state region. On this basis, a passive earth pressure calculation model of a narrow foundation pit is proposed and solved by differential layer method. The solution of the passive earth pressure coefficient strictly meets the static equilibrium conditions in vertical and horizontal directions as well as the moment equilibrium conditions. A numerical example is used to analyze the influence of the width of the foundation pit. The smaller the narrow foundation pit width, the greater the passive earth pressure in the lower soil layer and it even greatly exceeds the Coulomb earth pressure distribution. The earth pressure distribution acting on the lower part of the wall near the zero point of displacement decreases sharply and bends. The passive earth pressure distribution is calculated by the theoretical method and compared with the laboratory model test results as well as the engineering test results. It is found that the proper selection of the initial soil mechanical parameters affects significantly the magnitude and distribution of lateral pressure in the nonlimit state region. When the internal friction angle of soil φ0 is small, the lateral pressure in the lower nonlimit state area is relatively small. When both φ0 and δ0 are small, the pressure distribution is closer to the test results and the existing theoretical calculation results.

Numerical Exploration of Transverse Sonic Jet In Hypersonic Cross-flow

At high altitudes, due to low air density, the control response of highly agile and manoeuvrable aerospace vehicles through conventional aerodynamic surfaces is rather slow and inadequate. The control demand of such vehicles can be met very effectively with high-pressure side jets positioned at different locations of the vehicle. Additionally, as none of the components of passive jet control intrudes in the flow path in a passive state, no additional drag is incurred. CFD methods are increasingly being used to characterize jet-controlled aerospace vehicles. Before using in the design exercise, CFD methods need to be validated against reliable experimental results to find its range of applications and error band. In this work, a recent experimental study of transverse sonic injection into Mach 5 hypersonic stream is numerically explored by solving three-dimensional Reynolds Averaged Navier Stokes (RANS) equations using a commercial CFD solver. The computed surface pressures show a reasonable match with experimental results for different momentum ratios of jet and free stream flows. The predictive capabilities of different turbulence models were assessed. The spreading and penetration characteristics of the injectant are analysed from the computed data. The computed penetration and spreading of the injectant depicts nearly linear dependence with the momentum ratio.

Corrosion Activity of Stainless Steel SS430 and Carbon Steel B450C in a Sodium Silicate Modified Limestone-Portland Cement Extract.

Stainless steel SS430 and carbon steel B450C were exposed for 30 days to the aqueous extract of sodium silicate-modified limestone-Portland cement as an alternative for the partial replacement of the Portland cement clinker. The initial pH of 12.60 was lowered and maintained at an average of 9.60, associated with air CO2 dissolution and acidification. As a result, the carbon steel lost its passive state, and the corrosion potential (OCP) reached a negative value of up to 296 mV, forming the corrosion layer of FeO, and FeOOH. In the meaning time, on the stainless steel SS430 surface, a passive layer of Cr2O3 grew in the presence of FeO, Fe2O3 and Cr(OH)3 corrosion products; thus, the OCP shifted to more positive values of +150 mV. It is suggested that a self-repassivation process took place on the SS430 surface due to the accumulation of alkaline sulfates on the interface. Because of the chloride attack, SS430 presented isolated pits, while on B450C, their area was extended. The quantitative analysis of EIS Nyquist and Bode diagrams revealed that the Rp of the corrosion process for SS430 was 2500 kΩcm2, ≈32 times lower in magnitude than on B450C, for which the passive layer tended to disappear, while that on SS430 was ≈0.82 nm.

Nudges, emojis, and memes: Mapping interpassivity theory onto digital civic culture

ABSTRACT Once lauded for liberating audiences from their passive state by granting voice, the digital public sphere today increasingly resembles a cacophony of disjointed voices datafied for the gain of giant tech firms. Instead of bemoaning the co-optation of users’ activity, we might find it timely to reconsider the possibility that users’ passivity might be at stake, the key assumption of interpassivity theory implying a delegation of one’s affective subject position under seeming interactive practices. This article reviews burgeoning research on interpassivity and brings it to bear on pervasive phenomena in digital interactive environments: nudges, emojis, and memes. Tracing the artificial canned laughter of the broadcast era to the famous internet adage, Poe’s law, I argue that strategic ambivalence, vitriolic joking, and irony weaponized by far-right online subcultures exploit the interactive nudge logic of social media affordances. The means of expressing authentic feelings afforded by digital media entail a fissure that trades in illusions which users disavow. This explains how surprising phenomena beyond belief, such as “meme magic,” gain symbolic power. The theoretical takeaway upends the key premise of cultural participation theory suggesting that rather than serving as a precondition, relentless interactivity might paradoxically undermine the democratic ethos of participatory culture.

Developed Country Diaspora Strategy Framework

Abstract As developed countries become more and more interested in implementing diaspora strategies, this article reviews relevant literature for diaspora strategy design and implementation and distils elements of existing typologies into a conceptual framework for evaluating developed country diaspora strategies. The framework is then applied to the evaluation of the diaspora policies of Ireland and Australia, which emerge as examples of engaged versus passive states in relation to their diasporas. Interviews with diaspora engagement practitioners are used to elucidate the policies and practices that underpin diaspora engagement strategies in these countries. The resulting analysis has implications for theorising diaspora engagement and offers practical lessons for other countries looking to connect with their diasporas.

Simile on sense of self, virocell and the COVID19 pandemic

The virocell concept of a viral lifecycle maintains that there are two main stages in a virus’s existence. The one is a passive state of a virion, which is not a living entity, and the second one is the virocell. In the state of virocell, a virus infects a host’s cell and hijacks its cellular machinery to achieve its own replication. Depending on the way that a cell reacts to a viral infection, it can have its activities or character as an individual living organism, suppressed completely, to some extent or not at all. In the article, the authors propose that there is analogy between the virocell theory as applied to the SARS-CoV-2 virus lifecycle and the sense of self for humans in the coronavirus pandemic world, and the post-COVID19 space-time. Methodology adopted is a combination of simile of Wittgenstein’s parallel cases, autoethnography, the virocell concept of the SARV-CoV-2 lifecycle and a multi-individual nature of one’s self based on the principles of the assemblage theory. The nature of human existence and the sense of self is defined as a relational notion which is tied to the societal educational standards, phases of developments of a human being and their fluid sense of self. The COVID19 pandemic space-time provides, in fact it demands that humanity undergoes an ongoing education of itself to maintain a productive and resilient movement forward for self and society, as an equivalent of the ribovirocell of a human cell infected with the coronavirus. The notion of speed will have to be unpacked and investigated further, which is done in part in a follow up article and is anchored as the defining characteristics of the post-COVID19 world.

Contribution of the oxygen reduction reaction to the electrochemical cathodic partial reaction for Mg-Al-Ca solid solutions

The electrochemical corrosion rate of magnesium depends on the stability of the surface layer formed. Based on the Mg substrate, the oxide structure comprises a dense MgO/Mg(OH)2 mixture underneath a porous plate-like Mg(OH)2 layer. While the kinetics of the anodic partial reaction have been mainly attributed to MgO, recent studies have showed an effect of the Mg(OH)2 layer thickness on the cathodic partial reaction. A thinner Mg(OH)2 layer has been associated with higher kinetics of the oxygen reduction reaction. In the present study, the mechanism has been further investigated via in situ respirometric measurements using Mg-Al-Ca solid solution in electrolytes with different pH values (pH = 8.0–13.0). The results indicate an additional effect based on the structure of the surface layer for Mg-Al-Ca alloys in the passive state. Furthermore, two different Al-enriched interfaces were observed and discussed in terms of their thermodynamic stability under alkaline immersion conditions.

On-line monitoring the corrosion rate of reinforcing steel in concrete under natural conditions using bimetallic batch sensors along the coast of Khanh Hoa (Vietnam)

A bimetallic batch sensor was proposed to assess the corrosion rate of steel reinforcement in concrete in the presence of chlorides under laboratory and marine conditions. The prepared sensor could generate an electric current independently, indicating the corrosion process's intensity. Moreover, this sensor did not require any external polarization, resulting in reducing the device's cost and power consumption. These advantages are very important when using sensors for autonomous monitoring systems away from energy sources. Laboratory tests in an aqueous extract of concrete have shown the possibility of a sensor to detect the transition from a passive state to corrosion with an increase in the concentration of chlorides. Activation was received when 0.010 < CCl ≤ 0.10 mol·dm−3. The boundary between the passive state and corrosion was obtained at a current density of 8.6 ± 0.5 μA·cm−2. The measurement results on the sensor coincided with the data of the anode polarization curves and the polarization resistance method. In addition, the monitoring system based on sensors was tested in the field conditions of Khanh Hoa (Vietnam) for four exposure conditions for nine months. The correspondence of the measured current for sensors with standard monitoring methods was obtained: the half-cell potential and the electrical resistivity. The most intense corrosion occurred for the samples placed in the splash zone or immersed to a depth of 1 m. The coefficient of conversion of the current on the sensor and the corrosion rate by the polarization resistance method for concrete samples was set to 69.9. Therefore, it is possible to use the current value on the sensor to predict the time to structural failure using well-known models based on data on the corrosion rate of reinforcement. The sensors could retain their functionality and integrity after 9 months of field tests. The current findings suggest a continuous monitoring system of the corrosion rate of steel reinforcement in marine conditions for practical applications.

Oral microbiota in active and passive states of recurrent aphthous stomatitis: An analysis of case-control studies

ObjectiveThis study was presented to reveal the most distinct microbial prevalence in recurrent aphthous stomatitis (RAS) lesions compared to healthy controls. DesignThe case-control studies were selected in electronic databases until Nov 2022 with key search terms, and the eligible publications were screened and analyzed by independent authors. ResultsA total of 14 studies were identified, which included 531 cases of active states of RAS (AS-RAS), 92 cases of passive states of RAS (PS-RAS) and 372 healthy controls. The most sample pattern was the mucosa swab performed in 8 of 14 studies, biopsies in 3 studies, followed by micro-brush, and saliva. A variety of bacteria in higher or lower abundance were observed in RAS lesions. ConclusionsThe etiopathogenesis of RAS may not be ascribed to a single pathogen. A possible explanation is that microbial interactions modify immune response or destroy the epithelial integrity, thus contributing to the development of the condition.

Construction and Optimization Strategy of County Ecological Infrastructure Network Based on MCR and Gravity Model—A Case Study of Langzhong County in Sichuan Province

Against the backdrop of rapid urbanization, there is a passive adaptation state shown in urban and rural ecological spaces. Due to the shrinking of ecological patches and the fracture of corridors, problems such as the obstruction of ecological processes, the decline of ecosystem services, and the loss of biodiversity occur. Considering that county ecological space is the key level to undertake provincial ecological security patterns and implement ecological demonstration projects, the construction of a county ecological infrastructure (EI) network is beneficial to the protection of regional ecological security, the improvement of the structures and functions of farmland ecosystems, and the enhancement of the quality of human settlements. In this study, taking Langzhong County in Sichuan Province as an example, a method path for an EI network construction was explored, and an optimization strategy for ecological patterns was proposed. Firstly, morphological spatial pattern analysis (MSPA) and a patch importance index were employed to identify ecological sources. Secondly, by constructing a landscape resistance surface and adopting a minimum cumulative resistance (MCR) model, potential EI corridor paths were extracted. Thirdly, the interaction force values between ecological sources were calculated with a gravity model and important ecological corridors were identified for priority protection and restoration. Finally, an EI corridor network was optimized by combining network structure indexes (α, β, and γ) with the field situation, and stepping stone patches and ecological breakpoints were identified. Based on the analysis results, an ecological protection pattern, which involved three vertical and two horizontal ecological belts, four ecological control zones, and six clusters of EI networks in Langzhong County, was put forward, aiming at protecting 50 ecological sources, repairing 105 ecological corridors of different grades, adding 9 stepping stone patches near long-distance corridors and 15 at the intersection of ecological corridors, and repairing 18 ecological breakpoints. This study has guiding significance for the optimization of county ecological patterns, the construction of farmland forest belts, and site selection of ecological restoration projects.

Penerapan Model Kooperatif Tipe Jigsaw terhadap Hasil Belajar Siswa pada Materi Perpindahan Kalor di Kelas V SD Karya Budi Banda Aceh

The study is titled Application of Collaborative Puzzle Learning Model to Learning Outcomes of Heat Transfer Materials for Students of Class V SD Karya Budi Banda Aceh. The problem in this study is that teachers often use lectures in teaching, which makes students in a passive state in learning activities. The problem formulation was how to apply the jigsaw cooperative learning model to the learning outcomes of fifth grade students in SD Karya Budi Banda Aceh in heat transfer materials. The purpose of this study was to describe the learning outcomes of fifth grade students in SD Karya Budi Banda Aceh about heat transfer materials using the jigsaw puzzle model. The subjects of this study are the students of Class V, with a total of 28 students. This research method is qualitative while the research type is descriptive. Data collection techniques are performed through testing. Data analysis uses percentage formulas. After analyzing the data, the result obtained is 89.00%. According to the results of the study, it was concluded that the application of the jigsaw cooperative model to heat transfer material could achieve complete student learning outcomes.Keywords: Jigsaw Type Cooperative Model, Learning Outcomes, Heat Transfer Materials, Science

Initial-state-dependent quantum speed limit for dissipative state preparation: Framework and optimization

Dissipation has traditionally been considered a hindrance to quantum information processing, but recent studies have shown that it can be harnessed to generate desired quantum states. To be useful for practical applications, the ability to speed up the dissipative evolution is crucial. In this study, we focus on a Markovian dissipative-state-preparation scheme in which the prepared state is one of the energy eigenstates. We derive an initial-state-dependent quantum speed limit (QSL) that offers a more refined measure of the actual evolution time compared to the commonly used initial-state-independent relaxation time. This allows for passive optimization of dissipative evolution across different initial states. By minimizing the dissipated heat during the preparation process, conditioned on the minimization of evolution time using the QSL, we find that the preferred initial state has a specific permutation of diagonal elements with respect to an ordered energy eigenbasis of increasing eigenvalues. In this configuration, the population on the prepared state is the largest, and the remaining diagonal elements are sorted in an order resembling that of a passive state in the same ordered energy eigenbasis. We demonstrate the effectiveness of our strategy in a dissipative Rydberg-atom system for preparing the Bell state. Our work provides insights into the optimization of dissipative-state-preparation processes and could have significant implications for practical quantum technologies.

Interface modification of perovskite solar cell for synergistic effect of surface defect passivation and excited state property enhancement

The efficiency of perovskite solar cell (PSC) is significantly affected by the charge transport and recombination behaviors at the interfaces between the perovskite photoactive layer and charge transport intermediate layers. Especially, the defects, existing in those interfaces, induce non-radiative charge carrier recombination, reducing the stability of the device along with its performance. In this work, we newly design an imidazole- and methoxy-functionalized triphenylamine based hole-transport material (HTM), which has defect-passivating functionality together with proper carrier-transportation property, for the p-i-n PSC devices. Additionally, it is also designed to preserve its enhanced molecular dipole moment at the excited-state with longer lifetime through excited-state intramolecular proton transfer (ESIPT) process, consequently beneficial to improve the Vbi of the device. The designed HTM molecule, having a synergistic effect of defect-passivation and photo-enhanced dipole characteristic, is confirmed to be advantageous to produce PSCs with higher performance and stability.

Chamber Protection of Zinc with Ethylhexanoic Acid.

Chamber protection is a promising and quickly developing method of vapor-phase protection of metals against atmospheric corrosion by inhibitors. It was shown that chamber treatment with 2-ethylhexanoic acid (EHA) efficiently inhibits the initiation of zinc corrosion. The optimum conditions (temperature and duration) of zinc treatment with vapors of this compound were determined. If these conditions are met, adsorption films of EHA with thicknesses up to 100 nm are formed on the metal surface. It was found that their protective properties increase during the first day as zinc is exposed to air after chamber treatment. The anticorrosive action of adsorption films is due both to the surface being shielded from the corrosive environment and to the inhibition of corrosion processes on the active surface of the metal. Corrosion inhibition was caused by the ability of EHA to convert zinc to the passive state and inhibit its local anionic depassivation.

Reflections on the Cultivation of Applied Talents in the Economics Major under the OBE Concept

Under the traditional teaching concept, students are in a passive learning state, accepting knowledge and completing tasks step by step according to the teacher’s requirements. In the process of cultivating talents in economics, there are problems such as “emphasizing theory over practice, emphasizing deduction over analysis, emphasizing assessment over application”. Starting from the OBE concept, this paper takes XX University as an example and proposes optimization and improvement ideas for the talent cultivation in economics, focusing on aspects such as setting talent cultivation objectives, investigating social demands, emphasizing ability cultivation, clarifying the roles of teachers and students, designing teaching methods, and evaluating learning outcomes.

Sensor fault diagnosis modeling of lithium-ion batteries for electric vehicles

Electric Vehicles (EVs) are considered the replacement for gas-emitting and environmentally polluting fuel vehicles. The development of EVs relies on electronic devices and communication circuits for ease of access. The heart of EVs is the battery that requires post-run-time charging and precise maintenance. Electronic sensors attached to the batteries monitor their health, discharging, and charging rate for user notification and prolonged functioning. Therefore, the operation of the sensors is to be monitored promptly for effective battery maintenance. This article introduces a Fault Detection Method (FDM) using Operational Data (OD) accumulated from the EV. This data is first split into active and passive that references the run-time and idle time of the vehicle. The sensor operations during the idle time are considered similar due to minimal or no sensing function. Contrarily the run-time observation shows up variations that are not huge compared to the previous history. In this data verification process, recurrent learning is employed for identifying variations in the active and passive states of the EVs. If variations are continuous regardless of the active and passive states, then the sensor is identified as faulty post the manual battery life assessment. The learning is trained using the current and previous sensor observations and batter health for identifying the variations.

Basal glutamate in the hippocampus and the dorsolateral prefrontal cortex in schizophrenia: Relationships to cognitive proficiency investigated with structural equation modelling

Objectives Schizophrenia is characterised by deficits across multiple cognitive domains and altered glutamate related neuroplasticity. The purpose was to investigate whether glutamate deficits are related to cognition in schizophrenia, and whether glutamate-cognition relationships are different between schizophrenia and controls. Methods Magnetic resonance spectroscopy (MRS) at 3 Tesla was acquired from the dorsolateral prefrontal cortex (dlPFC) and hippocampus in 44 schizophrenia participants and 39 controls during passive viewing visual task. Cognitive performance (working memory, episodic memory, and processing speed) was assessed on a separate session. Group differences in neurochemistry and mediation/moderation effects using structural equation modelling (SEM) were investigated. Results Schizophrenia participants showed lower hippocampal glutamate (p = .0044) and myo-Inositol (p = .023) levels, and non-significant dlPFC levels. Schizophrenia participants also demonstrated poorer cognitive performance (p < .0032). SEM-analyses demonstrated no mediation or moderation effects, however, an opposing dlPFC glutamate-processing speed association between groups was observed. Conclusions Hippocampal glutamate deficits in schizophrenia participants are consistent with evidence of reduced neuropil density. Moreover, SEM analyses indicated that hippocampal glutamate deficits in schizophrenia participants as measured during a passive state were not driven by poorer cognitive ability. We suggest that functional MRS may provide a better framework for investigating glutamate-cognition relationships in schizophrenia.