Polarization Process Research Articles

Traveling fronts in vibrated polar disks: At the crossroad between polar ordering and jamming.

We investigate experimentally the collective motion of polar vibrated disks in an annular geometry, varying both the packing fraction and the amplitude of the angular noise. For low enough noise and large enough density, an overall collective motion takes place along the tangential direction. The spatial organization of the flow reveals the presence of polar bands of large density, as expected from the commonly accepted picture of the transition to collective motion in systems of aligning polar active particles. However, in our case, the low density phase is also polar, consistent with what is observed when jamming takes place in a very high density flock. Interestingly, while in that case the particles in the high density bands are arrested, resulting in an upstream propagation at a constant speed, in our case the bands travel downstream with a density-dependent speed. We demonstrate from local measurements of the packing fraction, alignment, and flow speeds that the bands observed here result both from a polar ordering process and a motility induced phase separation mechanism.

A global dataset of pitted cones on Mars

Pitted cones are positive-relief features that display prominent central craters, and are common features on the northern lowland plains of Mars. Pitted cones have been proposed to form from different mechanisms, including those producing volcanic cinder cones or sedimentary mud volcanoes. Here, we apply a deep learning model to globally map 65,620 pitted cones on Mars using Context Camera images from the Mars Reconnaissance Orbiter. Using model recall and a hand-mapped dataset, we conjecture there could be up to ∼81,900–162,000 individual pitted cones on Mars. A majority of pitted cones (>97%) occur in three of the northern plains' basins—Utopia, Isidis, and Acidalia Planitiae—and occur within geologic units from the late Hesperian and the early–middle Amazonian. The global dataset shows cone estimated diameter increases moving poleward, but pitted cones largely disappear north of ∼50 N, perhaps due to polar processes that erase or modify the cones. Approximately 94% of cones overlie a single geologic unit, the Vastitas Borealis Formation (VBF), interpreted as sediment from the highland terrains deposited via outflow channels. This global distribution supports sedimentary volcanism following deposition of sediments by the outflow channels. On Earth, rapidly-deposited sediments make an ideal setting for trapping water in the subsurface that is later erupted as mud flows, and this appears to be feasible on Mars.

A computational analysis of the role of integrins and Rho-GTPases in the emergence and disruption of apical-basal polarization in renal epithelial cells.

Apical-basal polarization in renal epithelial cells is crucial to renal function and an important trigger for tubule formation in kidney development. Loss of polarity can induce epithelial-to-mesenchymal transition (EMT), which can lead to kidney pathologies. Understanding the relative and combined roles of the involved proteins and their interactions that govern epithelial polarity may provide insights for controlling the process of polarization via chemical or mechanical manipulations in an in vitro or in vivo setting. Here, we developed a computational framework that integrates several known interactions between integrins, Rho-GTPases Rho, Rac and Cdc42, and polarity complexes Par and Scribble, to study their mutual roles in the emergence of polarization. The modeled protein interactions were shown to induce the emergence of polarized distributions of Rho-GTPases, which in turn led to the accumulation of apical and basal polarity complexes Par and Scribble at their respective poles, effectively recapitulating polarization. Our multiparametric sensitivity analysis suggested that polarization depends foremost on the mutual inhibition between Rac and Rho. Next, we used the computational framework to investigate the role of integrins and GTPases in the generation and disruption of polarization. We found that a minimum concentration of integrins is required to catalyze the process of polarization. Furthermore, loss of polarization was found to be only inducible via complete degradation of the Rho-GTPases Rho and Cdc42, suggesting that polarization is fairly stable once it is established. Comparison of our computational predictions against data from in vitro experiments in which we induced EMT in renal epithelial cells while quantifying the relative Rho-GTPase levels, displayed that EMT coincides with a large reduction in the Rho-GTPase Rho. Collectively, these results demonstrate the essential roles of integrins and Rho-GTPases in the establishment and disruption of apical-basal polarity and thereby provide handles for the in vitro or in vivo regulation of polarity.

Exploring the impact of solvent additives on dielectric properties in polymer photovoltaics: A deconvolution and in-depth study of electrical modulus, complex conductivity, and impedance responses

Impedance and dielectric spectroscopy is a well-known technique for characterizing interfaces, especially donor/receiver interfaces in bulk heterojunction (BHJ) solar cells. This technique was employed to investigate the interface of poly (4,8-bis-alkyloxybenzo(1,2-b:4,5-b0) dithio-phene-2,6-diyl-alt- (alkyl thieno (3,4-b) thiophene-2-carboxylate)-2,6-diyl) (PBDTTT-C): PC70BM in bulk heterojunction with DIO as additive. For this reason, a simulation was carried out to generate the complex impedance, modulus, and complex conductivity data based on the electrical parameters extracted from the equivalent circuit. Therefore, a new approach based on the coupling of complex functions such as impedance, modulus, and conductivity has been proposed. In addition, an extrapolation and deconvolution approaches are used to highlight the relaxation processes, the BHJ layer process, the two electrical contacts of the interfaces between PEDOT: PSS/PBDTTT-C: PC70BM and PBDTTT-C: PC70BM/Ca process, and the electrode polarization process. In the next step, the remove the low-frequency process enhances the visibility of other processes, particularly observable in the evolution of the electrical modulus and the conduction parameters associated with each process. In the complex functions, there was a good correlation between all parameters derived from both processes. The characteristics of the conduction processes, such as conductivity values at low and high frequencies and ionic strength were then extracted. All these parameters were evaluated and discussed as a function of the thickness of the active layer. Finally, we demonstrate that the electrical modulus and complex conductivity can be perfect tools to characterize the donor/acceptor interfaces.

Three-Stage Interpolation Method for Demosaicking Monochrome Polarization DoFP Images.

The emergence of polarization image sensors presents both opportunities and challenges for real-time full-polarization reconstruction in scene imaging. This paper presents an innovative three-stage interpolation method specifically tailored for monochrome polarization image demosaicking, emphasizing both precision and processing speed. The method introduces a novel linear interpolation model based on polarization channel difference priors in the initial two stages. To enhance results through bidirectional interpolation, a continuous adaptive edge detection method based on variance differences is employed for weighted averaging. In the third stage, a total intensity map, derived from the previous two stages, is integrated into a residual interpolation process, thereby further elevating estimation precision. The proposed method undergoes validation using publicly available advanced datasets, showcasing superior performance in both global parameter evaluations and local visual details when compared with existing state-of-the-art techniques.

Study the Effect of “Di-dodecyl amine” as a Corrosion Inhibitor for Carbon Steel in HCl Medium

Numerous organic compounds have been investigated for their potential to reduce corrosion under various circumstances. This study investigated the effects of di-dodecyl amine, an organic chemical, on carbon steel metal corrosion at different temperatures while HCl acid was present. The examination was carried out using accepted methods for polarization, weight loss, and corrosion process testing. The obtained findings demonstrated that the corrosion rate reduces with increasing inhibitor concentration, leading to increased inhibition efficiency. Furthermore, as shown in the weight loss technique, the corrosion rate lowers with increasing surface coverage with organic inhibitor at 313 °C. In the anodic and cathodic polarization methods, as well as in the inhibition efficiency, it is observed to see the cathodic and anodic curves through which the occurrence of the potential and corrosion current is known. The current and corrosion potential decreases with increasing inhibitor concentration. The amines and methyl motiveless in this inhibitor's composition give it their efficacy since they may coat the metal surface and stop corrosion

Integrating Sulfur Doping with a Multi-Heterointerface Fe7S8/NiS@C Composite for Wideband Microwave Absorption.

Heterointerface engineering is presently considered a valuable strategy for enhancing the microwave absorption (MA) properties of materials via compositional modification and structural design. In this study, a sulfur-doped multi-interfacial composite (Fe7S8/NiS@C) coated with NiFe-layered double hydroxides (LDHs) is successfully prepared using a hydrothermal method and post-high-temperature vulcanization. When assembled into twisted surfaces, the NiFe-LDH nanosheets exhibit porous morphologies, improving impedance matching, and microwave scattering. Sulfur doping in composites generates heterointerfaces, numerous sulfur vacancies, and lattice defects, which facilitate the polarization process to enhance MA. Owing to the controllable heterointerface design, the unique porous structure induced multiple heterointerfaces, numerous vacancies, and defects, endowing the Fe7S8/NiS@C composite with an enhanced MA capability. In particular, the minimum reflection loss (RLmin) value reached -58.1dB at 15.8GHz at a thickness of 2.1mm, and a broad effective absorption bandwidth (EAB) value of 7.3GHz is achieved at 2.5mm. Therefore, the Fe7S8/NiS@C composite exhibits remarkable potential as a high-efficiency MA material owing to the synergistic effects of the polarization processes, multiple scatterings, porous structures, and impedance matching.

Fam96a is essential for the host control of Toxoplasma gondii infection by fine-tuning macrophage polarization via an iron-dependent mechanism.

Toxoplasmosis affects a quarter of the world's population. Toxoplasma gondii (T.gondii) is an intracellular parasitic protozoa. Macrophages are necessary for proliferation and spread of T.gondii by regulating immunity and metabolism. Family with sequence similarity 96A (Fam96a; formally named Ciao2a) is an evolutionarily conserved protein that is highly expressed in macrophages, but whether it play a role in control of T. gondii infection is unknown. In this study, we utilized myeloid cell-specific knockout mice to test its role in anti-T. gondii immunity. The results showed that myeloid cell-specific deletion of Fam96a led to exacerbate both acute and chronic toxoplasmosis after exposure to T. gondii. This was related to a defectively reprogrammed polarization in Fam96a-deficient macrophages inhibited the induction of immune effector molecules, including iNOS, by suppressing interferon/STAT1 signaling. Fam96a regulated macrophage polarization process was in part dependent on its ability to fine-tuning intracellular iron (Fe) homeostasis in response to inflammatory stimuli. In addition, Fam96a regulated the mitochondrial oxidative phosphorylation or related events that involved in control of T. gondii. All these findings suggest that Fam96a ablation in macrophages disrupts iron homeostasis and inhibits immune effector molecules, which may aggravate both acute and chronic toxoplasmosis. It highlights that Fam96a may autonomously act as a critical gatekeeper of T. gondii control in macrophages.

High-precision identification of polarization processes of proton exchange membrane fuel cells through relaxation time analysis: Targeted experimental design and verification

Distribution of relaxation time (DRT) technology can achieve more precise decoupling of polarization process of proton exchange membrane fuel cell (PEMFC). However, except for the two peaks of DRT at low frequency, which are widely acknowledged to the cathode charge transfer impedance and the oxygen mass transfer impedance, there has been ongoing debate regarding the interpretation of other peaks observed at high frequency. In this work, the single-state variable control method is introduced by design of the membrane electrode assembly (MEA) and corresponding working operating conditions to simulate performance degradation factors of PEMFC, enabling accurate identification and verification of each peak in DRT. Based on the previous understanding that peaks P1 and P2 are oxygen mass transfer impedance and cathode charge transfer impedance, peaks P3-P5, ranging from high to low time scales, are determined to correspond to the other three polarization impedances. Specifically, peaks P3 and P4 are influenced by ionomer content in cathode and anode catalyst layers, respectively, and exhibit a decline with increasing humidity. They correspond to proton transfer processes within their respective catalyst layers. And the peak P5 is affected by anode catalyst loading and displays an increase with rising current density at low loading, signifying its involvement in the charge transfer process of anodic hydrogen oxidation reaction. A novel ECM was developed, consisting of five series-connected Randles circuits with polarization significance. The cathode and anode were separated in this design. The results demonstrate the enhanced sensitivity of DRT analysis to the performance degradation of PEMFC caused by oxygen transfer, charge transfer, and proton migration. This perspective provides a clear refinement for prior work of DRT polarization characteristic peaks.

Testing the inhibition efficiency of the castor oil leaf as corrosion inhibitor of mild steel in H2SO4

This study focused on the testing of castor oil leaf as corrosion inhibitor of mild steel in H2SO4. It involved the examination of the dynamics of molecular forces at the inhibitor and mild steel interface. Findings of the study will promote industrial diversification of castor oil leaf. On the experiment, bio-molecular compounds of the leaf were identified by gas chromatography mass spectrophotometer. Then, gravimetric and potentiodynamic polarization techniques were employed, where the efficacy and type of the inhibitor were determined. Considering the gravimetric process, factors of inhibitor concentration (0.2 g/L - 1.0 g/L), temperature (303 K–333 K) and time (8 h–24 h) were considered, with the inhibitor efficiency as the response. The efficiency was determined and optimized using response surface methodology (RSM) and artificial neural network (ANN). On the other hand, potentiodynamic polarization process was used to identify the type of inhibitor. Adsorption quantities were ascertained through the subjection of the experimental raw data to various adsorption isotherms. The analyses showed that castor oil leaf contains methyl nicotinate and pyridine-4-carbohydrazide. The bio-molecular compounds possess heteroatoms (N, S and O), signifying strong corrosion inhibitive tendencies. High efficiency (96.25 %) was obtained, with ANN having better prediction capability than the RSM. Potentiodynamic polarization curves revealed castor oil leaf as mixed-type inhibitor. On the adsorption phenomenon, the process of the inhibition was best fitted by Frumkin isotherm, revealing physical adsorption mechanism of Gibb's free energy less than −40 kJ/mol. As a mixed-type inhibitor, castor oil leaf should be applied for mitigation of anodic and cathodic corrosion.

RHO OF PLANTS signalling and the activating ROP GUANINE NUCLEOTIDE EXCHANGE FACTORS: specificity in cellular signal transduction in plants.

Every cell constantly receives signals from its neighbours or the environment. In plants, most signals are perceived by RECEPTOR-LIKE KINASEs (RLKs) and then transmitted into the cell. The molecular switches RHO OF PLANTS (ROP) are critical proteins for polar signal transduction and regulate multiple cell polarity processes downstream of RLKs. Many ROP-regulating proteins and scaffold proteins of the ROP complex are known. However, the spatiotemporal ROP signalling complex composition is not yet understood. Moreover, how specificity is achieved in different ROP signalling pathways within one cell still needs to be determined. This review gives an overview of recent advances in ROP signalling and how specificity by downstream scaffold proteins can be achieved. The composition of the ROP signalling complexes is discussed, focusing on the possibility of the simultaneous presence of ROP activators and inactivators within the same complex to balance ROP activity. Furthermore, this review highlights the function of plant-specific ROP GUANINE NUCLEOTIDE EXCHANGE FACTORS polarizing ROP signalling and defining the specificity of the initiated ROP signalling pathway.

Facile preparation of ZIF-67 on TiO2 and enhancement photocathodic protection for 316L stainless steel

Photocathodic protection (PCP) anticorrosion using sunlight is a green and sustainable technology. However, the ease of carriers compounding and the low light utilization are still the main restraints to its development. To develop an effective photoanode, a metal-organic framework (MOF, i.e., ZIF-67) material is electrodeposited and grown in-situ on TiO2 nanorods. The morphological structure, light absorption properties, photoelectrochemical properties and cathodic protection principle of ZIF-67/TiO2 photoanode are analysed by SEM, PL, I-V and EIS. The material characterization and light absorption characteristics show that the photoanode has good light absorption performance and higher electron hole separation efficiency. Photoelectrochemical test shows that ZIF-67/TiO2 photoanode has excellent photocathodic protection for 316L stainless steel (316L SS). ZTRs-60 has the optimal protection effect. Under simulated sunlight, the OCP of 316L SS coupled ZTRs-60 is -0.41 V vs. Ag/AgCl, and the current density of the I-t curve can reach 20 μA/cm2. EIS and Tafel tests show that the photogenerated electrons transfer to the stainless steel surface, which promotes the cathode polarization process and alleviates the metal corrosion.

Polar-coordinate line-projection light-curing continuous 3D printing for tubular structures

3D printing techniques offer an effective method in fabricating complex radially multi-material structures. However, it is challenging for complex and delicate radially multi-material model geometries without supporting structures, such as tissue vessels and tubular graft, among others. In this work, we tackle these challenges by developing a polar digital light processing technique which uses a rod as the printing platform. The 3D model fabrication is accomplished through line projection. The rotation and translation of the rod are synchronized to project and illuminate the photosensitive material volume. By controlling the distance between the rod and the printing window, we achieved the printing of tubular structures with a minimum wall thickness as thin as 50 micrometers. By controlling the width of fine slits at the printing window, we achieved the printing of structures with a minimum feature size of 10 micrometers. Our process accomplished the fabrication of thin-walled tubular graft structure with a thickness of only 100 micrometers and lengths of several centimeters within a timeframe of just 100 s. Additionally, it enables the printing of axial multi-material structures, thereby achieving adjustable mechanical strength. This method is conducive to rapid customization of tubular grafts and the manufacturing of tubular components in fields such as dentistry, aerospace, and more.

Lithium-ion battery sudden death: Safety degradation and failure mechanism

Environmental pollution and energy scarcity have acted as catalysts for the energy revolution, particularly driving the rapid progression of vehicle electrification. Lithium-ion batteries play a fundamental role as the pivotal components in electric vehicles. Nevertheless, battery sudden death poses substantial challenges to battery design and management. This work comprehensively investigates the failure mechanism of cell sudden death under different degradation paths and its impact on cell performances. Multi-angle characterization analysis shows that lithium plating is the primary failure mechanism of battery sudden death under different degradation paths. However, the formation mechanisms of lithium plating differ in various degradation paths. In the path-L and path-F, the limited lithium intercalation rate in graphite leads to lithium plating, while localized anode drying and uneven potential distribution are the causes in the path-H and path-R. Furthermore, sudden death significantly reduces the cell electrochemical performances and thermal safety, but the cell performance evolution varies under different degradation paths. Sudden death primarily affects the anode interface polarization process in the path-L and path-F, with a more severe impact on cell thermal safety. However, sudden death mainly affects the charge transfer process, with a relatively milder impact on cell thermal safety. These findings can provide valuable insights for optimizing battery design and management.

Variation of electrical properties with temperature for polyethylene oxide doped with 0.1 wt. % iodine

The electrical properties of thin films made of polyethylene oxide (PEO) dispersed with dopants fixed amount of iodine (0.1 wt. %) were studied using the AC impedance technique. The films were prepared by electrically casting method. In this present work, the variation of AC electrical conductivity with temperatures ranging from 30 oC to 55 oC at a frequency of 200 kHz for (PEO) film doped with 0.1wt. % iodine and undoped (PEO) film were studied. Physical quantities and parameters such as AC conductivity, impedance, dielectric constant, and dielectric loss, were determined. The observed values of the impedance (Z), dielectric constant ('), dielectric loss ("), and AC-conductivity (σAC) showed temperature dependence. It was found that the dielectric constant and the dielectric loss of the prepared thin films increased with doped (0.1wt. %) iodine complexes and also increased with the increase of temperature according to the polarization processes.

Gaining a better understanding of online polarization by approaching it as a dynamic process.

Polarization is often a cliché, its conceptualization remains approximate and no consensus has been reached so far. Often simply seen as an inevitable result of the use of social networks, polarization cannot be viewed solely from an ideological or affective perspective. We propose to better understand the issue polarization by approaching it as a sequential process, drawing on a dual expertise in political and data sciences. We compare the polarization process between one mature debate (COVID-19 vaccine) and one emerging debate (Ukraine conflict) at the time of data collection. Both debates are studied on Twitter users, a highly politicized population, and on the French population to provide key elements beyond the traditional US context. This unprecedented analysis confirms that polarization varies over time, through a succession of specific periods, whose existence and duration depend on the maturity of the debate. Importantly, we highlight that polarization is paced by context-related events. Bearing this in mind, we pave the way for a new generation of personalized depolarization strategies, adapted to the context and maturity of debates.

A Lithium-Ion Battery Remaining Useful Life Prediction Method with A New Algorithm Based on Incremental Capacity Analysis

Safe use of lithium-ion batteries requires accurately assessing state of charge (SoC), state of health (SOH) and capacity estimation techniques. Due to numerous charge and discharge cycles, lithium ion batteries undergo a degradation process during their use leading to failures, accidents, and fire. Traditional ICA/DVA methods have been used to overcome these issues, but they are subject to changes in battery resistance and polarization processes during battery aging. Evaluation of the SoC as a function of incremental capacity is proposed in this work to overcome this problem. This article used a new algorithm to perform, through simulations carried out with Matlab® software, incremental capacity analysis for a preventive estimate of remaining useful life (RUL). In addition, the comparison between IC curves and the SoC here used fully represents the relationship between the IC values and the internal parameters of the battery. The validity of the proposed algorithm against the phenomenon of battery aging was evaluated based on experimental data from NASA's PCoE research center.

Low-loss polarization-maintaining optical router for photonic quantum information processing

In photonic quantum applications, optical routers are required to handle single photons with low loss, high speed, and preservation of their quantum states. Single-photon routing with maintained polarization states is particularly important for utilizing them as qubits. Here, we demonstrate a polarization-maintaining electro-optic router compatible with single photons. Our custom electro-optic modulator is embedded in a configuration of a Mach–Zehnder interferometer, where each optical component achieves polarization-maintaining operation. We observe the performance of the router with 2%–4% loss, 20 dB switching extinction ratio, 2.9 ns rise time, and >99% polarization process fidelity to an ideal identity operation.

Exploring Dielectric and Magnetic Properties of Ni and Co Ferrites through Biopolymer Composite Films

This study explores the synthesis and characterization of chitosan/gelatine films incorporating nickel ferrite (NiFe2O4) and cobalt ferrite (CoFe2O4) nanoparticles. The magnetic nanoparticles exhibit superparamagnetic behaviour, making them attractive for various applications, including biomedical uses. The X-ray diffraction analysis confirmed the successful synthesis of NiFe2O4 and CoFe2O4 nanoparticles, and the scanning electron micrographs illustrated well-dispersed ferrite nanoparticles within the biopolymer network, despite the formation of some aggregates attributed to magnetic interactions. Magnetization loops revealed lower saturation magnetization values for the composites, attributed to the chitosan/gelatine coating and the dielectric studies, indicating increased dielectric losses in the presence of ferrites, particularly pronounced in the case of NiFe2O4, suggesting interactions at the interface region between the polymer and ferrite particles. The AC conductivity shows almost linear frequency dependence, associated with proton polarization and conduction processes, more significant at higher temperatures for samples with ferrite particles.

Unraveling the potential of Morinda officinalis oligosaccharides as an adjuvant of escitalopram in depression treatment and exploring the underlying mechanisms

Ethnophamacological relevanceMorinda officinalis oligosaccharides (MOs) is a mixture of oligosaccharides extracted from the roots of Morinda officinalis (MO). It is approved by Chinese Food and Drug Administration (CFDA) for depression treatment. MOs could improve the antidepressant efficacy of escitalopram in clinic. Aim of the studyWe aim to explore the antidepressant activity and potential mechanism of the combination usage of MOs and escitalopram on animal model of depression. Materials and methodsDepressive animal model was induced by chronic mild stress (CMS). Behavioral tests were conducted to evaluate the antidepressant efficacy of MOs and escitalopram. Serum neurotransmitter levels were detected by High-performance liquid chromatography (HPLC). Quantitative real-time PCR and Western blotting were applied to assay the hippocampus neurotrophic factors’ mRNA and protein levels. Peripheral cytokines levels were measured through Enzyme-Linked Immunosorbent Assay (ELISA). Micorglia polization phenotype was assayed by immunofluorescence and flow cytometry. ResultsMOs and escitalopram obviously attenuated depression-like behaviors of CMS mice. Importantly, MOs plus escitalopram exhibited better antidepressant activity on CMS mice than monotherapy. At the same time, MOs combined escitalopram treatment significantly increased hippocampus neurotransmitters and neurotrophic factor levels, stimulated hippocampus neurogenesis and relieved central nervous system (CNS) microglia over-activation of CMS mice. The combination therapy had greater effect on neuroprotection and inflammation attenuation of CMS mice than monotherapy. ConclusionOur results indicates MOs combined escitalopram might produce antidepressant activity through protecting neuron activity, relieving inflammation and modulating microglia polarization process.