Characteristic Behavior Research Articles

The zebrafish mutant dreammist implicates sodium homeostasis in sleep regulation

Sleep is a nearly universal feature of animal behaviour, yet many of the molecular, genetic, and neuronal substrates that orchestrate sleep/wake transitions lie undiscovered. Employing a viral insertion sleep screen in larval zebrafish, we identified a novel gene, dreammist (dmist), whose loss results in behavioural hyperactivity and reduced sleep at night. The neuronally expressed dmist gene is conserved across vertebrates and encodes a small single-pass transmembrane protein that is structurally similar to the Na+,K+-ATPase regulator, FXYD1/Phospholemman. Disruption of either fxyd1 or atp1a3a, a Na+,K+-ATPase alpha-3 subunit associated with several heritable movement disorders in humans, led to decreased night-time sleep. Since atpa1a3a and dmist mutants have elevated intracellular Na+ levels and non-additive effects on sleep amount at night, we propose that Dmist-dependent enhancement of Na+ pump function modulates neuronal excitability to maintain normal sleep behaviour.

Characteristic Behavior of Cross-Anisotropic Deposits of Granular Soils

Characteristic Behavior of Cross-Anisotropic Deposits of Granular Soils

On the Interaction of Damage Evolution and Thermal Buckling in Stepped Circular Bilaminates

Abstract The behavior and evolution of stepped circular bi-laminates with edge damage are studied for structures subjected to uniform thermal load. The problem is formulated as a moving intermediate boundaries problem in the calculus of variations, where the boundary of an evolving region of damage emanating from the edge of the smaller substructure, as well as the boundary of a progressing/regressing region of sliding contact adjacent to the intact region of the composite structure are each allowed to vary along with the displacements. This yields the associated transversality conditions that define the locations of the propagating boundaries that correspond to equilibrium configurations of the evolving composite structure, as well as the equations of equilibrium and the associated interior and exterior boundary conditions. Various configurations of contact of the detached segments of the composite structure and the associated behavior are considered, and the influence and progression of contact on the overall evolution of the composite structure are assessed. Closed-form analytical solutions to the geometrically nonlinear problem are obtained, and expressions for the critical buckling load are developed. The explicit forms of the total energy release rate along the delamination front, as well as of the conditions for propagation of the contact zone boundary, are obtained from the analytical solutions and the corresponding transversality conditions. Results of numerical simulations based on the analytical solutions are presented and are seen to unveil a rich evolution process involving contact progression/recession and metamorphosis, buckling, and detachment progression during the prebuckling phase, during sling-shot buckling, and during the postbuckling phase, depending on the material properties of the sublaminates, the geometry of the sublaminates, the initial size of the damage, and the strength of the interfacial bond. Characteristic behavior of damage propagation is found to be quite robust and is seen to include stable propagation, stable followed by unstable progression, arrest, and catastrophic propagation.

Autonomous fault detection and diagnosis for permanent magnet synchronous motors using combined variational mode decomposition, the Hilbert-Huang transform, and a convolutional neural network

The continuous and online monitoring of the condition of electrical machines is key to their safe operation. This study introduces a novel fault detection and diagnosis technique for continuous monitoring of faults in permanent magnet synchronous motors (PMSM). The proposed method relies solely on built-in sensors (stator phase currents only) to detect three types of faults: inter-turn short circuit, partial demagnetisation, and static eccentricity. Our fault detection and diagnosis strategy was developed by combining variational mode decomposition (VMD), the Hilbert-Huang transform (HHT) and a convolutional neural network (CNN). The VMD is first applied to the stator phase current signals to analyse the characteristic behaviour of the current signals by decomposing the current signals into several intrinsic mode functions. The intrinsic mode functions of the healthy and faulty signals are compared, and that with the frequency shift characteristics is selected. HHT is then applied to extract the fault feature by calculating the instantaneous frequency. Finally, the instantaneous frequency feature is fed into the CNN, which is designed to detect and classify motor faults. Experimental results clearly show that the variation of the instantaneous frequency of the PMSM, working at different operating states, can be utilised for condition monitoring and fault detection.

Energy evolution mechanism of a PVDF activated nano-aluminum based metastable intermixed composites

The preparation and energy release mechanism of highly reactive n-Al/F-polymer metastable intermixed composites are both desirable and challenging. In this study, we employed an optimized electrospray sampling strategy to significantly enhance the reaction activity of aluminum-based MICs, as well as their combustion performance. It is evident that the optimization of the sampling strategy yielded remarkable results. Compared to the physical mixture, MICs-1 exhibited a 7.2-fold and 9.9-fold increase in Pmax and Pmax/Δt, respectively. The combustion rate experienced an 8.5-fold improvement, and the energy release efficiency rose from 52.18 % to 68.11 %. An analysis of the energy evolution mechanism reveals a mitigation of the reactive sintering phenomenon observed in MICs-1. The presence of PVDF facilitates the reactivity of aluminum powders by selectively corroding the alumina shell. The reaction kinetics parameters indicate that MICs-1 demonstrates characteristic three-step reaction behavior and exhibits a lower reaction energy barrier. Furthermore, ReaxFF molecular dynamics simulations demonstrate the adsorption and dissociation of PVDF on the surface of aluminum powders, leading to erosion defects in the alumina crystal structure. These defects, in turn, induce the ignition reaction.

Optimization of dissolved hydrogen concentration for mitigating corrosive conditions of pressurized water reactor primary coolant under irradiation (1) evaluation of water radiolysis

ABSTRACT A major subject for evaluating the corrosive conditions in the pressurized water reactor (PWR) primary coolant is to determine the optimal hydrogen concentration for mitigating primary water stress corrosion cracking (PWSCC) without adverse effects on major structural materials. An analytical method combining water radiolysis and electrochemical corrosion potential (ECP) analyses was proposed for evaluating the corrosive conditions in PWR primary coolant. These procedures originally developed for boiling water reactors (BWRs) were successfully extended to PWRs with different water chemistry parameters, including pH, temperature, and radiation qualities, after minor changes in the original procedures and major input parameters, such as the inclusion of the effects of alpha radiolysis and Li+ (Na+) and H+ effects for the anodic polarization curve. This study discusses the results of water radiolysis analysis for PWR primary coolant, and the characteristic behavior of hydrogen peroxide (H2O2) as a function of hydrogen inlet concentrations in PWR primary coolant conditions (higher pH and α-ray irradiation). A possible reaction scheme involving eaq – was proposed for H2O2 suppression under alkaline conditions. The corrosive conditions were discussed in the following publication, using ECP as the major index for PWR corrosive conditions.

Reanalysis of single-cell data reveals macrophage subsets associated with the immunotherapy response and prognosis of patients with endometrial cancer

Endometrial cancer (EC) is an aggressive gynecological malignancy with an increased incidence rate. The immune landscape crucially affects immunotherapy efficacy and prognosis in EC patients. Here, we characterized the distinct tumor microenvironment signatures of EC tumors by analyzing single-cell RNA sequencing data from Gene Expression Omnibus and bulk RNA sequencing data from The Cancer Genome Atlas, which were compared with normal endometrium. Three macrophage subsets were identified, and two of them showed tissue-specific distribution. One of the macrophage subsets was dominant in macrophages derived from EC and exhibited characteristic behaviors such as promoting tumor growth and metastasis. One of the other macrophage subsets was mainly found in normal endometrium and served functions related to antigen presentation. We also identified a macrophage subset that was found in both EC and normal endometrial tissue. However, the pathway and cellular cross-talk of this subset were completely different based on the respective origin, suggesting a tumor-related differentiation mechanism of macrophages. Additionally, the tumor-enriched macrophage subset was found to predict immunotherapy responses in EC. Notably, we selected six genes from macrophage subset markers that could predict the survival of EC patients, SCL8A1, TXN, ANXA5, CST3, CD74 and NANS, and constructed a prognostic signature. To verify the signature, we identified immunohistochemistry for the tumor samples of 83 EC patients based on the selected genes and further followed up with the survival of the patients. Our results provide strong evidence that the signature can effectively predict the prognosis of EC patients.

First-principles study of graphene intercalation in h-BN based resistance random access memory

Graphene intercalation between metal electrode and resistance layers has attracted extensive experimental and theoretical research because of its capability to manipulate the electronic structure and properties of hexagonal boron nitride based resistance random access memory. Herein, the interface characteristic, adsorption and migration behavior of Ti on pristine and defective graphene intercalation have been systematically investigated by utilizing the density functional theory method, which could help accurately preset defects and regulate the permeation process. Analysis of the interfacial contact form showed that Ohmic-type contact occurs between intercalation and resistance layer interface due to the heavy doping effect caused by charge accumulation on the h-BN layer surface upon introduction of intercalation. Ti metal adsorption at hollow site on defective graphene containing grain boundary with double vacancies was more energetically favorable than that on pristine graphene without vacancy or with single vacancy, whereas the increase of adsorption energy caused by grain boundary defects that represented by pentagons and heptagons and double vacancies were very limited. Migration barrier calculations with defect distribution and vacancy indicated that the critical factor controlling ion penetration in the whole intercalation process is the presetting of single vacancy defect rather than the varying number of vacancies and the existence of grain boundary defect. This finding provides a new perspective aiding understanding and design of the defect-assisted graphene intercalation mechanism.

Compression Characteristic and Creep Behavior of Moraine Soil at Xingkang Bridge, West Sichuan, China

Compression Characteristic and Creep Behavior of Moraine Soil at Xingkang Bridge, West Sichuan, China

Unsteady natural-convection MHD flow of the generalized Maxwell fluid past a canted porous plate

The natural-convection magnetohydrodynamic (MHD) flow usually takes place in the process of many industries, such as astrophysics and electronics. In this work, the MHD flow characteristic and heat behavior about the generalized Maxwell fluid passing the canted porous plate under the titled magnetic field is investigated, which is stemmed from the effect of the heat absorption, thermal radiation, the first-order chemical reaction and radiation absorption. And for the temperature and concentration, we established the single-phase-lag model to describe the anomalous transported process. By utilizing the Laplace-transform (L-T) and Fourier-sine transform (F-ST), the solutions in the transformed domain about velocity, temperature, concentration are given analytically. Then the semi-analytical solution can be denoted via the inverse F-ST and numerical inverse L-T. Further, the cognate parameters’ impacts on the solution are discussed and the results are displayed intuitively via profiles.

Energy Repartition and Entropy Generation across the Earth’s Bow Shock: MMS Observations

The evolution of plasma entropy and the process of plasma energy redistribution at the collisionless plasma shock front are evaluated based on the high temporal resolution data from the four Magnetospheric Multiscale spacecraft during the crossing of the terrestrial bow shock. The ion distribution function has been separated into the populations with different characteristic behaviors in the vicinity of the shock: the upstream core population, the reflected ions, the gyrating ions, the ions trapped in the vicinity of the shock, and the downstream core population. The values of ion and electron moments (density, bulk velocity, and temperature) have been determined separately for these populations. It is shown that the solar wind core population bulk velocity slows down mainly in the ramp with the electrostatic potential increase but not in the foot region as it was supposed. The reflected ion population determines the foot region properties, so the proton temperature peak in the foot region is an effect of the relative motion of the different ion populations, rather than an actual increase in the thermal speed of any of the ion population. The ion entropy evaluated showed a significant increase across the shock: the enhancement of the ion entropy occurs in the foot of the shock front and at the ramp, where the reflected ions are emerging in addition to the upstream solar wind ions, the anisotropy growing to generate the bursts of ion-scale electrostatic waves. The entropy of electrons across the shock does not show a significant change: electron heating goes almost adiabatically.

Temperature-directed fluorescent switchable nanoparticles based on P3OT–PNIPAM nanogel composite

Poly(N-isopropylacrylamide) (PNIPAM) is a unique stimuli-responsive material that exhibits a lower critical solution temperature (LCST). Owing to this characteristic temperature-dependent behavior, PNIPAM has found extensive utilization as an active material in various applications, including sensors, drug delivery, and cellular imaging. Herein, we demonstrate temperature-directed fluorescent switchable nanoparticles based on poly(3-octylthiophene-2,5-diyl) (P3OT) nanoaggregate-embedded PNIPAM nanogel composites (POPNs) featuring different crosslinker contents. The amount of P3OT loading in the nanogel composites can be gradually controlled by varying the crosslinking density of the PNIPAM matrix; this may be attributable to the efficient entrapment of P3OT nanoaggregates in case of a dense polymeric network with the increase in crosslinking density. POPNs exhibit dramatic temperature-dependent fluorescence enhancement (by a factor of 2.11). This is based on the environmental changes affecting fluorescent P3OT chains at temperatures below and above the LCST of the PNIPAM matrix. Based on this temperature-directed fluorescent switching capability, POPN could find potential applications in various fields, including biomedical imaging and sensors.

Mixed Spin Ising Ferrimagnetic System in the Oguchi Approximation

It has been investigated an Ising ferrimagnet with mixed spin-2 and spin-5/2 and various crystal field parameters on a body-centered cubic lattice. In this research paper, ferrimagnetic compensation temperatures and phase transitions to clarify the characteristic features, in a series of molecular-based magnets AFeIIFeIII(C2O4)3[A=N(n-CnH2n+1)4, n=3-5] are examined in the Oguchi approximation (OA). The spin crystal domain dependence of compensation behavior acting on ions contain the Oguchi lattice, is mainly studied. It is discovered, specifically, that magnetic anisotropies in the disordered for the two sublattices of the model depend on the negative values of the crystal fields to produce a characteristic ferrimagnetic behavior. For DA/|J|=-1.5 and DB/|J|=-5.5, there are two compensation points are induced at an ordered phase(2,-1.5).

Investigation on Surface Characteristic and Tribological Behavior of BS960 Steel by Using Micro-shot Peening and Traditional Shot Peening

Investigation on Surface Characteristic and Tribological Behavior of BS960 Steel by Using Micro-shot Peening and Traditional Shot Peening

Can the splitting joint reproduce the characteristics of the natural joint in the lab? —A comparison study based on the roughness analysis and shear test

Splitting joints have been widely used to study the morphology characteristic and shear behavior of rock joints in the laboratory. There are some differences between the splitting joint and natural joint both in morphology characteristic and shear behavior. To quantitatively compare the differences, the present study used several splitting joints and natural joints to carry out the roughness analysis and direct shear test. Six profiles were extracted from each joint surface with a 30° interval to calculate the 2D roughness parameters (i.e., amplitude roughness parameter, average asperity inclination, root-mean-square of profile slope, and joint roughness coefficient). These parameters of the natural joints have a wide range and have obvious fluctuation. On the contrary, these parameters of the splitting red sandstone joints converge on a small range with tiny fluctuation, even calculated from different joint surfaces. The directional parameter (θ⁎max(C + 1)) was adopted to calculate the 3D roughness with a 5° interval. The directional parameter of the natural joints in range of 0° ∼ 360° forms a peanut, a prolate ellipse, or a gourd shape, presenting significant anisotropy. For the splitting joints, it forms a circle or a roughly circular shape, presenting insignificant anisotropy. The asperity heights of natural joints mainly present an irregular distribution, and they present an approximately normal distribution in few joints. For the splitting joints, the asperity heights generally obey a normal distribution. It indicates that there are huge differences between natural joint and splitting joint in morphology characteristic. To study the shear behavior, two types of joint were reconstructed for repeated test. The mechanical performance and failure characteristic of the splitting joint under different shear directions are similar. On the contrary, those of the natural joints under different shear directions are different, presenting obvious anisotropy. Based on the comparative analysis of the natural joints and the sandstone splitting joints in the present study, there is substantial difference between two types of joints both in morphology characteristic and shear behavior. The splitting joints cannot reproduce the characteristics of the natural joints well.

Thermodynamics and Shadows of quantum-corrected Reissner–Nordström black hole surrounded by quintessence

In this work, we consider the quantum-corrected Reissner–Nordström black hole surrounded by quintessence matter and examine its thermodynamics and shadow. To this end, we handle the quantum-corrected metric of the black hole, which is given by Wu and Lui in 2022, and couple the quintessence matter field effects to the lapse function. Then, we obtain the mass, Hawking temperature, specific heat, and equation of state functions. In all these functions, we discuss two cases in which the quantum corrections are greater or smaller than the quintessence matter effects. We observe that within these two scenarios, the black hole has different characteristic thermal behaviors. Moreover, we find that the quintessence matter plays an important role in leading to a black hole remnant. Furthermore, we observe that black hole behaves like Van der Waals fluid. Finally, we investigate the black hole shadow by Carter’s approach. We find that quintessence matter and quantum corrections modify the shadow of the black hole.

Multi-scale procedure for the mechanical analysis of composite laminate structures considering mixed boundary conditions

This paper presents a multi-scale procedure for the study of flat composite structures with discontinuities. In this procedure, the structure is solved using shell elements while the laminate performance and the structural discontinuities (e.g. connections or change in the laminate thickness) are analysed with a subscale model made with solid 3D elements. The kinematics of both models are coupled following the Kirchhoff–Love theory. This coupling is used during the homogenization procedure where the characteristic behaviour of the different micro-models is obtained. Periodical boundary conditions are used for the laminates whereas a combination between periodical and linear boundary conditions are used for the discontinuities. The proposed procedure allows to reproduce accurately the structure elastic behaviour, as well as the stress and strain states in regions with discontinuities, which until now could only be accurately simulated by means of expensive numerical models using volumetric solid elements.

Modeling of extremely ductile behavior of Zr-based bulk metallic glasses under compressive strain paths for solid-state processing

In addition to extremely high strength, manufacturing temperatures of bulk metallic glasses (BMGs) relative to steels are low making them to desired energy saving engineering materials. However, BMGs are significantly brittle at low temperatures. To further increase suitability of BMGs for widespread use, it is essential to understand their plastic deformability (ductility) for high-tech solid-state processes at lowered temperatures. In this work, extremely large deformation behavior (near 80% in compression) of industrially important Zr-based BMGs was investigated. The experimentally measured results aided in the development of an appropriate constitutive model and revealed the micromechanisms affecting the characteristic macroscopic deformation behavior including softening and hardening. The measured and model results showed that the ductility can be significantly improved through chemical composition changes, such as a reduction in the Cu content and an increase in the Zr, Ti, or Be contents. In contrast to previously announced conclusions on the high glass-forming ability (GFA) being the precursors to ductility, formation of sufficiently low degree of crystallization during cooling improved ductility of as-cast specimens under loadings. These observed properties are important in assessing the ability of BMGs for solid-state processing.

Evaluation of orthotropic elasticity of gradient-structured bamboo by microtensile testing combined with digital image correlation technique

Bamboo, a biomaterial with a unique gradient structure, possesses exceptional mechanical properties. The gradient structure impacts the mechanical properties of bamboo in the longitudinal (L), radial (R) and tangential (T) directions. To investigate the elasticity associated with gradient structure, we derived the orthotropic elastic constants: Young’s modulus (E), Poisson’s ratio (ν) and shear modulus (G) at different radial positions (outer, central and inner) through micro-tensile testing and the digital image correlation (DIC) technique. Our results revealed that the Young’s modulus of bamboo exhibited a characteristic orthotropic behavior irrespective of radial position. The ratio of E in the L, T and R directions (EL:ET:ER) was 6.05:1.08:1, 5.12:1.17:1 and 8.02:1.58:1, respectively at the outer, central and inner positions. With increasing fiber fraction, ν (except νRT) demonstrated an upward trend. Under main axis tension, fiber pull-out and brittle fracture were the main failure modes, whereas off-axis tension exposed the vulnerable interface between fibers and parenchyma cells. The enhancement effect of the gradient structure in the L and T directions was more prominent, resulting in a consistent deformation pattern from the inner to outer positions. However, strain localization was found when tensioning through the R direction. Leveraging the derived orthotropic elastic constants, we visualized the three-dimensional elastic behavior of bamboo by body deformation. Bamboo at the outer position exhibited quasi-isotropic behavior in the RT plane due to the high fiber fraction. This study provides critical experimental evidence for the orthotropic behavior of bamboo at different radial positions and valuable data for mechanical modeling and practical applications involving bamboo.

Simulation of liquid production and water cut dynamics using fluid flow model and neural networks

In the oil industry, there is a noticeable tendency to use proxy modeling of various levels of complexity to perform operational predictive calculations, in particular machine learning methods that are actively developing in the context of digitalization and intellectualization of production processes. In this paper, using the example of a synthetic oil reservoir model development element, we present an approach to the joint use of a physically meaningful fluid flow model and machine learning methods for solving adaptation and prediction problems. A feature of the considered synthetic model is the presence of a pronounced zonal inhomogeneity of the permeability field. Within the framework of the proposed approach, a single-phase filtration model, simplified in comparison with the original formulation was used, the history matching of which was carried out by restoring the field of reservoir filtration parameters using a network of radial basis functions. Based on the reconstructed field, the connection coefficients between the wells were calculated, which qualitatively and quantitatively correspond to the true well connections. The next step was to train a recurrent neural network in order to predict the water cut of the produced fluid. The use of a recurrent neural network made it possible to reproduce the characteristic non-monotonic behavior of the water cut of the produced fluid, caused by non-stationary modes of operation of injection and production wells. A combination of the presented models makes it possible to predict the volume of the produced fluid and its phase composition. To assess the predictive properties of the models, the actual data set was divided into training and test intervals.