Flux Concept Research Articles

Irreversibility analysis of radiative TiO2+Al2O3+Cu/H2O ternary nanofluid flow over a bidirectional stretching sheet with cattaneo-christov heat flux: nanotechnology applications

Ternary nanofluids demonstrate better heat transfer characteristics in contrast to conventional liquids and typical hybrid nanofluids. These are applied in sophisticated cooling systems for electronics, heat exchangers, and automotive engines, along with renewable energy systems such as solar collectors, where efficient heat transfer plays a crucial role. The aim of this research is to investigate the movement of a Casson ternary nanofluid passing through a bidirectional exponential sheet by employing the innovative Cattaneo-Christov heat flux concept. The utilization of the energy equation considers thermal radiation, viscous dissipation, and heat source/sink effects, with the integration of chemical reaction effects into the concentration equation. An analysis of entropy generation is utilized to evaluate the thermodynamic irreversibility within the system. The conversion of transport equations involves a transformation from partial to ordinary differential equations, followed by a numerical solution utilizing the BVP4C solver embedded in the MATLAB package R2022b. The impacts of developed factors on thermal, concentration, and velocity behavior, as well as engineering quantities, are thoroughly explored graphically. The outcome reveals that the velocity gradients diminish as magnetic fields intensify, while it amplified by the Hall factor. The rise in temperature of ternary nanofluid correlates with elevated levels of radiation, and Brownian motion. Concentration intensifies with the rapid development of thermophoresis influences. Heightened values of the Reynolds and Brinkman numbers give rise to amplified entropy production but a decrease in the Bejan number. The ternary nanofluid displays a remarkable 8.92% increase in skin friction on the x-axis and y-axis, influenced by the potent Darcy-Forchheimer factor. The rates of mass and heat transfer in nanofluids undergo a decrease of 8.58% and 12.52%, respectively, due to the heightened influence of Brownian motion and Eckert number. The results could provide valuable insights into the performance of ternary nanofluids in various industrial environments under specific conditions.

Research on compressor cascade flow field modeling method based on finite volume flux-informed neural network

For compressor cascade flow field modeling, there exists strong velocity shear in the leading edge separation flow, boundary layer, and wake, which leads to increased modeling errors. To improve the accuracy of the flow field modeling method, this paper introduces the concept of numerical flux from the finite volume method into the loss function to implement Euler equation physics-informed learning, and a finite volume flux-informed neural network (FVFI-net) is constructed. Selecting a high-load, large-turning-angle compressor cascade as the study object, a comparative analysis is conducted on the advantages and disadvantages of purely data-driven, weak physical constraint, and finite volume flux-informed methods in compressor cascade flow field modeling. The study found that compared to purely data-driven and weak physical constraint methods, FVFI-net can reduce the average error of aerodynamic parameters in the flow field by approximately 45.6% and 29.5%, respectively, at a 0° angle of attack. For the flow separation problem occurring at the suction side leading edge and the blade wake area caused by a 5° angle of attack, FVFI-net can effectively reduce modeling errors near the leading edge, in the wake region, and near the periodic boundaries, thus reducing the average error of the aerodynamic parameters of the flow field by about 49.2%and 31.3%, respectively, compared to pure data-driven and weak physical constraint methods.

Active flux based adaptive and non-adaptive observer for sensorless interior permanent magnet synchronous machine drive

The use of the interior permanent magnet synchronous machine (IPMSM) drive has profoundly increased in a large number of applications due to numerous advantages. Owing to the disadvantages of mechanical sensors, sensorless control techniques are employed to enhance the performance of the IPMSM drive by removing the effect of noise and gain drift due to the sensor, increasing reliability, cost saving, and reducing overall size. This article presents the comparative analysis between the adaptive observer and non-adaptive extended electromotive force (EEMF) observer based on the active flux concept in a stationary reference frame (α–β). Moreover, the effect of slot harmonics and non-sinusoidal distribution of rotor flux is present in the three-phase IPMSM, this problem is considered as the control system disturbances in this article. Due to the non-sinusoidal distribution of flux and slot harmonics, the observer structure in the rotating reference frame (d–q) fails to estimate at the low-speed operation range. Comparative analysis between adaptive and non-adaptive observer structures is provided for a wide speed range. The effectiveness of the observer structures is examined using the classical field-oriented control scheme. In the end, simulation and experimental results are demonstrated to validate the performance of the sensorless control scheme using the adaptive and non-adaptive observer structures for the three-phase IPMSM drive setup.

Critical flux-based fouling control method for forward osmosis during simultaneous thickening and digestion of waste activated sludge

The use of forward osmosis (FO) membranes for simultaneous thickening and digestion of waste activated sludge (WAS) (FO-MSTD) has recently garnered significant interest. However, a major challenge hindering the widespread adoption of the FO-MSTD process is severe membrane fouling, which results from increasing sludge concentrations and deteriorating sludge properties. In response, this study proposes a novel FO membrane fouling control strategy based on the critical flux concept, involving a variable draw solution (DS) operating mode. Two operating modes were examined based on the critical flux behavior of the FO membrane: a constant DS concentration mode (with a fixed DS concentration of 1.5 M, referred to as Constant DS1.5) and a variable DS concentration mode (with varying DS concentrations at different operational stages, referred to as Variable DS1.5-1.0 and Variable DS1.5-0.75). Over 21 days of operation, the MLSS concentrations of WAS in the Constant DS1.5, Variable DS1.5-1.0, and Variable DS1.5-0.75 reactors increased from initial values of 3.46, 3.88, and 4.20 g/L to 35.2, 31.5, and 29.2 g/L, respectively. Concurrently, the cumulative digestion rates of MLVSS in the three FO-MSTD processes reached 29.3 %, 29.0 %, and 36.3 %, respectively. After adjusting the DS concentration, the FO membrane flux decay rates for Constant DS1.5, Variable DS1.5-1.0, and Variable DS1.5-0.75 were 57.7 %, 49.4 %, and 13.8 %, respectively. In addition to experiencing a lower flux decline, the Variable DS1.5–0.75 mode achieved a significantly higher flux recovery rate of 98.5 % compared to the other two modes. Moreover, the biovolume of proteins and microorganisms in the membrane fouling layer decreased by 85.2 % and 72.7 %, respectively, in the Variable DS1.5–0.75 mode compared to the Constant DS1.5 mode. These findings indicate that operating with a DS below the critical concentration can significantly improve the reversibility of membrane fouling and reduce the presence of organic and biological foulants in the fouling layer, thereby mitigating membrane fouling in the FO-MSTD reactor.

Uncovering underlying physical principles and driving forces of cell differentiation and reprogramming from single-cell transcriptomics

Recent advances in single-cell sequencing technology have revolutionized our ability to acquire whole transcriptome data. However, uncovering the underlying transcriptional drivers and nonequilibrium driving forces of cell function directly from these data remains challenging. We address this by learning cell state vector fields from discrete single-cell RNA velocity to quantify the single-cell global nonequilibrium driving forces as landscape and flux. From single-cell data, we quantified the Waddington landscape, showing that optimal paths for differentiation and reprogramming deviate from the naively expected landscape gradient paths and may not pass through landscape saddles at finite fluctuations, challenging conventional transition state estimation of kinetic rate for cell fate decisions due to the presence of the flux. A key insight from our study is that stem/progenitor cells necessitate greater energy dissipation for rapid cell cycles and self-renewal, maintaining pluripotency. We predict optimal developmental pathways and elucidate the nucleation mechanism of cell fate decisions, with transition states as nucleation sites and pioneer genes as nucleation seeds. The concept of loop flux quantifies the contributions of each cycle flux to cell state transitions, facilitating the understanding of cell dynamics and thermodynamic cost, and providing insights into optimizing biological functions. We also infer cell-cell interactions and cell-type-specific gene regulatory networks, encompassing feedback mechanisms and interaction intensities, predicting genetic perturbation effects on cell fate decisions from single-cell omics data. Essentially, our methodology validates the landscape and flux theory, along with its associated quantifications, offering a framework for exploring the physical principles underlying cellular differentiation and reprogramming and broader biological processes through high-throughput single-cell sequencing experiments.

A concept in flux and starved of the metaphysical: desecularizing emotion.

Despite being of undisputed importance, there is no consensus on what emotions are, with the majority of research that constructs ideas about them being colored by a particular worldview. This conceptual article examines the case for conducting an Islamic analysis of emotion. It might seem a peculiar area to examine; what would be the need to analyze such a universal psychological concept through the lens of a particular religion? Three points are used to argue for this endeavor. To begin with, this article highlights the relative instability of the term; there is yet no universally agreed upon definition of what emotions are, and which human processes they contribute to. As the concept is still being defined, there is merit in engaging with the discussion, particularly given the relative absence of metaphysics from the debate. Secondly, specificities relating to emotions and how they have conceptualized are considered. This section delves into the way in which variable factors, such as culture, language, and worldview, influence how emotions manifest. The overarching point argued for here is that how emotions are experienced, and even which emotions are experienced, are shaped by factors that are not consistent across time and space. Accordingly, different worldviews will formulate different "emotional palates" and "emotional ideologies"; different groups of people will understand and engage with emotions differently. Thirdly, a broader discussion ensues pertaining to the nature of science, psychology, and their relationship with secularity. This discussion includes critique of the idea that forces such as secularism and scientific materialism have been "discovered" and are therefore value-neutral. Accordingly, understandings of emotions to have emerged from the Academy, and contemporary psychology, are value-laden. This section also looks at the origins of science in order to determine whether it is inherently atheistic or areligious, and therefore antagonistic to a religious worldview. The section also challenges the apparent secularity of psychology and key psychologists. A range of other facets pertaining to how the emotions have been conceptualized, such as their relational core, their interaction with moral faculties, and their enmeshment with what is important to individuals and groups, are also considered.

Aesthetic flux: inquiring into the sensuous dynamics of children, matter and environments with a more-than-human lens

Although sensuous and embodied engagement is an integral part of child–environment relationalities, the intersections of aesthetics, children and environments remain scarcely addressed. As a response, this study develops a concept of ‘aesthetic flux’ to delve into the sensuous dynamics of matter and bodies in the context of a storying workshop in a forest with first graders in a Finnish primary school. An arts-based, post-qualitative methodology guided our analysis of video recordings from the workshop, resulting in visual-sonic montages that draw attention to the intense movements and sounds of children, soap bubbles, air, a research camera and trees. Thinking through the concept of aesthetic flux, our study experiments with the abundance, indeterminacy and potentiality of sensuous dynamics where bodies (human and otherwise) become together and linger. Thus, our study reconfigures aesthetics as a creative and unpredictable force that materialises in both embodied and conceptual ways in environmental education and research with children.

Enzyme Kinetics Based on the Concept of Flux

Enzyme Kinetics Based on the Concept of Flux

Towards liminal balance: Unpacking the UK's urban canal space

AbstractThis paper critically examines the liminal geographies of the United Kingdom's 7,000‐mile canal and river network, embodying a thread of complex intersections and interactions between water and land. Drawing on a study involving stakeholder interviews, group discussion with canal users, and observational walks in Manchester and London, the paper explores the concepts of liminal flux, scalar intersections, and deliminalisation. We first outline how the UK's urban canals are characterised by liminal flux over time and space, reflecting their dynamic geographies. Revealing the presence of critical intersections between liminality and scale, we then focus on the ongoing and everyday spatial and territorial entanglements between different canal and towpath users. Finally, we consider the challenge of deliminalisation, and an associated shift from liminality and in‐betweenness towards greater spatial fixity via neoliberal intervention and development. Our findings highlight the importance of preserving the unique characteristics of urban canals as liminal spaces, arguing that they provide recreational opportunities and contribute to urban wellbeing by providing opportunities for ‘transitory dwelling places’. Maintaining a liminal balance within urban canal environments is therefore crucial and requires careful curation. In turn, this notion of curating liminal balance has implications for other potential waterfront developments that offer a similar positive potential for hydrocitizenship and its fluid ambiguities of in‐betweenness. Moreover, it demonstrates the importance of a ‘lighter touch’ of redevelopment and governance in some parts of the urban environment to help preserve, or even enhance, citizen wellbeing.

Triple-System Theory of Individual Decision-Making Based on the Concept of Flux

Triple-System Theory of Individual Decision-Making Based on the Concept of Flux

Numerical and experimental study on the synergistic effect of vortex and contact surface of fluid in the inlet section of micromixer

The promoting effect of vortex on the mixing performance of micromixer is difficult to be quantitatively evaluated. In this study, the concept of flux across line (FAL) is proposed for the first time to quantitatively analyze the influence of synergistic effect between the vortex and the contact surface of fluid on the mixing. The FAL value of T-shaped and cross-shaped micromixers is obtained by integrating the velocity component after decomposing the velocity vector on the cross section of the straight channel. The intensity distribution and development of vortex in the inlet section are quantitatively revealed by numerical simulation at Re = 50. According to the FAL analysis, a two-layer feed T-shaped micromixer (TLFT-shaped) is designed to verify the effective synergy between vortex and contact surface of fluid. The FAL value of TLFT-shaped is 40–50 % higher than that of cross-shaped, the promoting effect of vortex on mixing is reflected in the mixing index, which experiences a notable 56 % increase. The concentration distributions of visualization experiments and simulations are consistent, which proves the accuracy of simulation results. The FAL analysis can quantitatively evaluate the promotion effect of vortex on mixing, which provides valuable guidance for the design of microfluidic devices.

Sonic play: on the B-side of literacy and songwriting

PurposeThis paper aims to explore sonic play in close proximity to a music, literacy and songwriting for social change community-based initiative. The authors leverage ideas about time, space and narrative under the concept of sonic flux to understand youth’s sonic and aural play on digital beatmaking technologies. In doing so, the authors break from a fixation on the written and spoken word and address sound, aurality and Blacktronika creative technologies that are often present but muted in literacies and songwriting scholarship.Design/methodology/approachThe authors’ team consisted of three community-based teaching artists who situated this inquiry around their own practice with youth. The authors conducted this inquiry through a qualitative, participatory and community-engaged research approach. As such, the authors codeveloped and carried out research questions and sense-making protocols that balance the power of interpretation and epistemologies among us.FindingsThe findings address how the joy, laughter and play of one young musician, Malik, moved across different conceptions of time while learning to make beats in proximity to peers writing lyrics for songs. Specifically, the authors unpack how Malik’s play with mobile sound-making technologies moved across linear and nonlinear time that characterize sonic space and sound art, not music and lyric writing. In doing so, the loops and durations of his sonic play were sometimes unbound by narrative structures that often code literacy and songwriting initiatives.Originality/valueThe authors’ inquiry speaks into literacy and songwriting initiatives that privilege spoken, written and performed word over sound. The authors ask what kind of participating structures, collaborations, ontologies and youth epistemologies open up if we think of youth in these spaces not only as performers but as programmers tinkering with time in the machine. In addition, the authors ask what literacy and songwriting spaces might look like when the duration, loops and drones of sonic space and not music are the structuring codes over narratives and linearity.

Reactivity of alloxydim herbicide: force and reaction electronic flux profiles

The reaction force profile and the electronic reaction flux concepts were explored for the herbicide alloxydim and some of its derivatives at B3LYP/6-311G(d,p) level of theory. The exploration was achieved by rotating the oxime bond which is the most reactive region of the molecule. The main objective is to understand how the rotation of this bond influences the properties of the molecule and induces an electronic reorganization. The results show that the rotation of the dihedral angle triggers alloxydim to go through three transition states. The first step of the transformation begins by the rupture of the hydrogen bond and is characterized by a pronounced structural reorganization. In the last step of the process the electronic reorganization is more important.

MAXIMUM MOMENTUM FLUX FOR STABILITY ANALYSIS OF MODEL AND PROTOTYPE BREAKWATERS

None of the established formulae for breakwater armour stone stability, Hudson (1958) or van der Meer (1987), explicitly account for the water depth at the toe of the structure. More recently, Hughes (2004), Melby and Hughes (2004), Melby and Kobayashi (2011) have developed equations for stability and runup utilising the concept of wave momentum flux which explicitly accounts for the water depth of the wave probe(s) in close proximity to the structure. The equations are adapted to three forms; namely (1) linear, (2) extended-linear and (3) non-linear. In the paper linearity is assessed by using the Ursell number at each probe depth. Also, due to the placement of probes at various depths in MHL’s 2D wave flume it is possible to correlate the linearity of the wave measurement for the same time series and subsequently test the appropriateness of the momentum flux equation applied for assessment of stability and runup. The stability and runup data from 43 2D physical model tests where stability was previously assessed using van der Meer’s and Hudson’s equations are assessed using the momentum flux equations and an evaluation of the results has been made. It was found that the estimation of notional permeability and selection of the use of the plunging or surging formulae was critical to obtaining a closer match between measurement and prediction. The equations were also utilised in conjunction with numerical models to evaluate the armour size for repair of two breakwater heads in South Camden Haven and Bellambi. The maximum momentum flux equations were found to perform satisfactorily at these locations where the Ursell numbers were found to be high and the waves non-linear.

감수성의 통합과 통각의 초월적 통합

Immanuel Kant argued that the object does not represent the state of the thing-in-itself, but becomes a phenomenon constructed by human subjectivity in general, and this is called the Copernican revolution. Kant is a philosopher representing German Idealism, followed by Bradley and Bergson. In the meantime, it has been assumed that Eliot’s core poetics developed from the cognitive framework of Bergson or Bradley: the concept of flux that grasps the time of the past, present, and future as an indivisible continuum in mutually organic relationships, immediate experience, historical consciousness, Impersonality, and unification of sensitivity, etc. in “Tradition and Individual Talent,” “Hamlet,” and “Metaphysical Poets.” However, in the “Report on Kant’s Categories” submitted by Eliot to a philosophy class at Harvard University in Mar. 2013, it can be confirmed that Eliot was already aware of Kant’s transcendental philosophy. Eliot’s unification of sensibility, which represents an experience in which, intellect and sensibility are unified, is nothing other than Kant’s transcendental unity of apperception.

Virtual Flux Direct Power Control for Vienna Rectifier Under Unbalanced Grid

The Vienna rectifier is being broadly utilized in many industrial applications, which makes it essential to address its challenges. This article conducts the virtual flux-based direct power control and proposes an improved switching table for the Vienna rectifier under a balanced or unbalanced grid's voltage. Accordingly, the proposed method improves the THD of the three-phase input current when the grid voltage is unbalanced. Moreover, employing the virtual flux concept eliminates using three-phase input voltage. This results in reducing the cost of the converter. One of the challenges in the Vienna rectifier is to consider the current direction in the control design. Accordingly, the proposed switching table is designed based on the input current's sector. Furthermore, the positive and negative sequences of the input currents and virtual flux are utilized to correctly estimate the instantaneous input active and reactive power under the unbalanced grid voltage condition. Moreover, the proposed method can balance the output capacitors in balanced and unbalanced grid voltage conditions. This method possesses a high dynamic response due to hysteresis bands. Finally, a 430-watt laboratory prototype of the Vienna rectifier is implemented, and the accuracy of the proposed VFDPC is verified through the experimental results.

Mathematical modeling of anomalous diffusive behavior in transdermal drug-delivery including time-delayed flux concept

Molecular transport through a composite multilayer membrane is a central process in transdermal drug delivery (TDD). Classical Fickean approach treats skin as a pseudo-homogenous membrane, while in reality skin is highly heterogeneous system as shown in basic physiological research. Particle transport across such systems shows anomalous diffusive behavior that is described by fractional models. These models don't consider experimentally observed dependence of particle transport nature on time scale. The possible way of inclusion of that observation in model of transdermal transport is presented in this paper. The generalized fractional models of the spectral functions of the concentration profile and the cumulative amount of the drug absorbed through the bloodstream are derived. The derived model predicts resonances in concentration profile and larger cumulative amount of the drug in both the short-time limit and the long-time limit, which can have significant physiological implications.

Active Q Flux Concept for Sensorless Control of Synchronous Reluctance Machines

This paper proposes a new scheme to use active flux on q-axis for sensorless control of synchronous reluctance machines (SynRM). Conventionally, “Active Flux” on d-axis is adopted to convert a salient pole machine into a fictitious non-salient pole machine. However, the injected d-axis flux can deteriorate high frequency injection (HFI) sensorless control performance or even run the system into unstable region at low speed. This paper demonstrates active flux on q-axis can support back-EMF sensorless control at high speed and improve low speed HFI performance substantially. A seamless transition from HFI sensorless method to back-EMF voltage method is attained after adopting the proposed active q flux. Experiment results are used to validate the proposed method.

Relating critical and limiting fluxes to metastable and long-term stable fluxes in colloidal membrane filtration through collision-attachment theory

In membrane technology for water/wastewater treatment, the concepts of critical flux (JC) and limiting flux (JL) suggest the existence of a threshold flux below which no fouling occurs. However, their important roles on stable flux duration have not been sufficiently understood. This work adopts a collision-attachment approach to clarify the relationship of JC, JL to metastable (i.e., short-term stable) and long-term stable fluxes based on their dependence on initial flux (J0), foulant-clean-membrane energy barrier (Ef-m), and foulant-fouled-membrane energy barrier (Ef-f). When J0 is below JL, water flux remains stable over a long time even for the case of J0 over JC, thanks to the strongly repulsive Ef-f. At J0 > JL and J0 > JC, the water flux is unstable at the beginning of filtration, and the flux ultimately decreases to JL as the long-term stable flux. Under the condition of JL < J0 ≤ JC, an initial metastable flux appears owing to the high Ef-m, with longer metastable period observed at lower J0 and for more hydrophilic/charged membrane or colloids. Nevertheless, rapid flux decline occurs subsequently due to the energy barrier shifting to weak Ef-f, and the water flux eventually degenerates to JL in long-term fouling duration. Our results provide significant guidelines for fouling control strategies with respect to membrane design, feedwater pretreatment, and operational optimization.

Astrocytic aerobic glycolysis provides lactate to support neuronal oxidative metabolism in the hippocampus.

Under physiological conditions, the energetic demand of the brain is met by glucose oxidation. However, ample evidence suggests that lactate produced by astrocytes through aerobic glycolysis may also be an oxidative fuel, highlighting the metabolic compartmentalization between neural cells. Herein, we investigate the roles of glucose and lactate in oxidative metabolism in hippocampal slices, a model that preserves neuron-glia interactions. To this purpose, we used high-resolution respirometry to measure oxygen consumption (O2 flux) at the whole tissue level and amperometric lactate microbiosensors to evaluate the concentration dynamics of extracellular lactate. We found that lactate is produced from glucose and transported to the extracellular space by neural cells in hippocampal tissue. Under resting conditions, endogenous lactate was used by neurons to support oxidative metabolism, which was boosted by exogenously added lactate even in the presence of excess glucose. Depolarization of hippocampal tissue with high K+ significantly increased the rate of oxidative phosphorylation, which was accompanied by a transient decrease in extracellular lactate concentration. Both effects were reverted by inhibition of the neuronal lactate transporter, monocarboxylate transporters 2 (MCT2), supporting the concept of an inward flux of lactate to neurons to fuel oxidative metabolism. We conclude that astrocytes are the main source of extracellular lactate which is used by neurons to fuel oxidative metabolism, both under resting and stimulated conditions.