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Spin-glass thin films exhibit many features different from the bulk. The freezing temperatures of spin-glass films are suppressed for reduced thickness and follow the Kenning relation. The dynamics are altered near the vacuum interface. These phenomena are closely related to the lower critical dimension of spin glasses, the spin-glass correlation length, and the dimensional crossover from d = 3 to d = 2. In this article, we review the experimental facts and theoretical perspectives for spin-glass thin films. We focus on canonical spin-glass systems with the Ruderman–Kittel–Kasuya–Yosida (RKKY) interaction between magnetic impurities in a nonmagnetic host. Open questions to be addressed are emphasized. [ABSTRACT FROM AUTHOR]

The assessment of spatial variability in the ground through field experiments has many constraints due to non-homogenous ground conditions and lack of site investigations. For this reason, spatial variability has not been considered in typical analyses. Also, few studies have been conducted on ground spatial variability using models in the laboratory. However, it is necessary to evaluate spatial variability in the ground for more precise analysis and design of construction projects. In this study, in order to evaluate spatial variability in the ground, we performed a number of Mini-Cone Penetration Tests (CPTs) in ground models with one layer of silica sand soil and two layers of silica and weathered soils. Through the Mini-CPTs, cone penetration resistances with depth were measured at many points. Based on the data, the coefficient of variation (CV) and the correlation length (CL) were calculated to quantitatively analyze the vertical and horizontal variability in the ground models. The results showed how the spatial variability in the two ground models varied. This implies that considering spatial variability in the ground can significantly enhance the accuracy of the analysis and design of construction projects. [ABSTRACT FROM AUTHOR]

This article explores the phenomenon of spiral wave breakup in cardiac arrhythmias. The researchers conducted studies on human and rabbit hearts using optical mapping and fluorescent indicators to observe the changes in calcium concentration and action potential duration. The goal of the research is to better understand ventricular tachycardia and ventricular fibrillation in order to improve prediction and treatment methods. The findings provide valuable insights into the mechanisms underlying these conditions. [Extracted from the article]

The stability of heterogeneous biopolymers is extremely important for maintaining their conformation and carrying out biological functions. The conformational stability of these molecules determines their ability to preserve the necessary structure for biological processes such as catalytic activity, molecular recognition, and cellular interactions. Within the framework of the Generalized Model of the Polypeptide Chain (GMPC), the correlation function of a two-component heteropolymer has been computed as a function of distance, specifically the number of repeating units between two monomers in a helical state, using the method of super-matrices. Through this research, dependencies of the correlation function on the number of repeating units between monomers in the helical state have been obtained for several realizations and different temperatures, particularly around the melting temperature. An interpolation dependency has been proposed for the curve at the melting temperature, expressed as a sum of exponential and power functions. This model allows for a more accurate description of the correlation function behavior under critical conditions close to the melting temperature. The exponential part of the model reflects intense decay of correlation at short distances, while the power function describes mild changes at longer distances. [ABSTRACT FROM AUTHOR]

Spin-glass thin films exhibit many features different from the bulk. The freezing temperatures of spin-glass films are suppressed for reduced thickness and follow the Kenning relation. The dynamics are altered near the vacuum interface. These phenomena are closely related to the lower critical dimension of spin glasses, the spin-glass correlation length, and the dimensional crossover from d = 3 to d = 2. In this article, we review the experimental facts and theoretical perspectives for spin-glass thin films. We focus on canonical spin-glass systems with the Ruderman–Kittel–Kasuya–Yosida (RKKY) interaction between magnetic impurities in a nonmagnetic host. Open questions to be addressed are emphasized.

The impact of non-Gaussian height distribution and spectral properties on the lubrication performance of counterformal (point) contacts is quantitatively studied (film parameter, Λ, and asperity load ratio, La) by developing a mixed lubrication model. The Weibull height distribution function and power spectral density (PSD) are used to generate artificial surface topographies (non-Gaussian and Gaussian, isotropic), as these surface topographies are found in many tribological components. The set of variables needed to parametrize and their effect on mixed lubrication is discussed, including the shape parameter, the autocorrelation length, the wavelength ratio, and the Hurst coefficient. It is revealed that a rough surface with a lower shape parameter exhibits higher hydrodynamic lift. The spectral properties (the autocorrelation length and the wavelength ratio) of rough surfaces significantly affect the film parameter and the hydrodynamic and asperity pressures. The film parameter is slightly influenced by the Hurst coefficient. [ABSTRACT FROM AUTHOR]

A new grid approximation of a homogeneous isotropic random field with a given average correlation length is developed. The approximation is constructed by partitioning the coordinate space into an ensemble of cubes whose size reproduces the average correlation length in the case of a field value chosen independently from a given one-dimensional distribution in each partition element. The correlative randomized algorithm recently proposed by the authors for modeling particle transport through a random medium is formulated. The accuracy and computational cost of corresponding Monte Carlo algorithms intended to compute gamma radiation transfer through a random medium of Voronoi diagram type are compared. To test the hypothesis that the one-dimensional distribution and the correlation length of the optical density of the medium have a large effect on radiation transfer, additional computations are performed for a random Poisson "field of air balls" in water. The grid approximation is generalized to anisotropic random fields. [ABSTRACT FROM AUTHOR]

Turbulence and transport phenomena play a crucial role in the confinement and stability of tokamak plasmas. Turbulent fluctuations in certain physical quantities, such as density or temperature fluctuations, can have a wide range of spatial scales, and understanding their correlation length is important for predicting and controlling the behavior of the plasma. The correlation length in the radial direction is identified as the critical length in real space. The dynamics in real space are of significant interest because transport in configuration space is primarily focused on them. When investigating transport caused by the E×B drift, the correlation length in real space represents the size of E×B whirls. It was numerically discovered that in drift wave turbulence, this length is inversely proportional to the normalized mode number of the fastest growing mode relative to the drift frequency. Considerable time was required before a proper analytical derivation of this condition was accomplished. Therefore, a connection has been established between phenomena occurring in real space and those occurring in k-space. Although accompanied by a turbulent spectrum in k-space with a substantial width, transport in real space is uniquely determined by the correlation length, allowing for accurate transport calculations through the dynamics of a single mode. Naturally, the dynamics are subject to nonlinear effects, with resonance broadening in frequency being the most significant nonlinear effect. Thus, mode number space is once again involved. Resonance broadening leads to the detuning of waves from particles, permitting a fluid treatment. It should be emphasized that the consideration here involves the total electric field, including the induction part, which becomes particularly important at higher beta plasmas.

The assessment of spatial variability in the ground through field experiments has many constraints due to non-homogenous ground conditions and lack of site investigations. For this reason, spatial variability has not been considered in typical analyses. Also, few studies have been conducted on ground spatial variability using models in the laboratory. However, it is necessary to evaluate spatial variability in the ground for more precise analysis and design of construction projects. In this study, in order to evaluate spatial variability in the ground, we performed a number of Mini-Cone Penetration Tests (CPTs) in ground models with one layer of silica sand soil and two layers of silica and weathered soils. Through the Mini-CPTs, cone penetration resistances with depth were measured at many points. Based on the data, the coefficient of variation (CV) and the correlation length (CL) were calculated to quantitatively analyze the vertical and horizontal variability in the ground models. The results showed how the spatial variability in the two ground models varied. This implies that considering spatial variability in the ground can significantly enhance the accuracy of the analysis and design of construction projects.

Germanium films were grown on c-plane sapphire with a 10 nm AlAs buffer layer using molecular beam epitaxy. The effects of Ge film thickness on the surface morphology and crystal structure were investigated using ex situ characterization techniques. The nucleation of Ge proceeds by forming (111) oriented three-dimensional islands with two rotational twin domains about the growth axis. The boundaries between the twin grains are the origin of the 0.2% strain and tilt grains. The transition to a single-grain orientation reduces the strain and results in a better-quality Ge buffer. Understanding the role of thickness on material quality during the Ge(111)/Al2O3(0001) epitaxy is vital for achieving device quality when using group IV material on the sapphire platform. [ABSTRACT FROM AUTHOR]

Biodegradable hydrogels have great potential in agriculture. In this study, hydrogel prototypes of biodegradable slow-release fertilizers were formulated by a Schiff base reaction between dialdehyde carboxymethyl cellulose and gelatin. The release behavior of iron cations from these carboxymethyl cellulose-based hydrogels with different degrees of substitution was studied. The analyses of the relation between correlation length of the cross-linked hydrogels and the degree of substitution, i.e., the amount of negatively charged positions in the hydrogels, allowed to determine the influence of structure and electrostatic interaction on cation release kinetics, which was successfully described by Peleg's Model. The hydrogel with the lowest degree of substitution reveals the slowest release of cations due to the smallest correlation length. These results demonstrate that the correlation length is dominant for the release of divalent cations. Moreover, this also shows the potential of the DACMC-Gelatin hydrogels as matrix for slow-release fertilizers. [ABSTRACT FROM AUTHOR]

Soil surface roughness is an important factor affecting hydrology and soil erosion processes, and its development is influenced by precipitation, topography, and tillage practices. In this study, the typical mollisol area in northeast China was taken as the research object. Then, the variation in soil surface roughness with time was analyzed under different terrains, as well as different tillage methods, and the effect of the precipitation condition on roughness was also discussed in detail. Through the design of field experiments, the height information of the soil surface was measured using a probe-type roughness plate. Two parameters, the root-mean-square height (RMSH) and the correlation length (CL), were selected to quantitatively characterize the soil surface roughness. In addition, the dynamic change patterns of surface roughness resulting from five tillage methods, including rotary tillage, combined tillage, no tillage, conventional tillage, and reduced tillage, under both sloping and flat land, were compared and analyzed throughout the soybean growing season, under the influence of rainfall. The results show that with the increase in rainfall, the RMSH of the soil surface, under different tillage methods, showed a trend of first decreasing, and then increasing. The results also showed that the RMSHs under rotary tillage, combined tillage, conventional tillage, and reduced tillage in flat land were greater than those in sloping land, and that the CLs of the soil surface under different tillage methods in flat land were smaller than those in sloping land. In addition, the degree of variation in the soil surface roughness was greater in flat land than that in sloping land under all tillage practices, indicating that this study is of great practical importance in the rational selection of tillage methods, and in the scientific quantification of soil erosion, which also show obvious significance for soil and water conservation. [ABSTRACT FROM AUTHOR]

The paper presents the results from studies of the electrical and magnetic properties of an inhomogeneous percolated medium based on the theory of percolation. The application of this theory has a wide and varied range. Examples include hopping conductivity in semiconductors, properties of porous materials, etc. It was found that, with approaching the percolation threshold pc = 0.35, the resistivity decreases, and the electrical conductivity increases accordingly. An increasing number of individual ferromagnetic nanogranules in (p)–Fe2O3–(1–p) (MBT) composites merge with the formation of individual Fe2O3 clusters in the bentonite matrix, which combine to form a continuous network of clusters. This is due to the fact that the resistivity ρ of the composite is mainly determined by the magnetic component of the latter. [ABSTRACT FROM AUTHOR]

This study develops a new spatial correlation model for Italy using the most up-to-date and densest dataset of accelerometer and velocimeter records available. The objective is to estimate the average correlation length and assess its impact on the prediction accuracy of the Italian Shakemap compared to the global model (Loth and Baker, 2013–LB13) adopted in the default configuration of the program. We compute the spatial covariance structure using a geostatistical approach based on traditional variography applied to standardized residuals within the events of a reference ground motion model (ITA10). We observe spatial clusters of the correlation lengths and a wide variability over the Italian territory linked to the profound heterogeneity of the geological and geomorphological context. The obtained estimates are then implemented within the LB13 co-regionalization model in place of the default values while assuming the same cross-correlation coefficients among spectral parameters. Although our results are quite consistent with previous models calibrated for Italy, we find that the inclusion of the new correlation lengths in the Shakemap predictions, assessed through a leave-one-out cross-validation technique, results in a non-appreciable improvement over the global model, thus indicating that the adopted approach is not able to resolve the regional features and the corresponding spatial correlation with reference to individual scenarios. These findings may suggest the need to move towards nonergodic models in the Shakemap computing to better capture the spatial variability or to determine different co-regionalisation matrices more suitable for the regional applications. [ABSTRACT FROM AUTHOR]

The aim of this paper is to present a model for the rheological behavior of simple liquids as a function of the amplitude of the imposed shear stress or strain. The elastic mode theory is first generalized to take into account the fact that, during a flow experiment, mechanical energy is injected in a system initially at thermodynamic equilibrium. This generalized theory can be seen as a particular aspect of the general problem of perturbation by the measurement, associated with that of the coupling between fluctuation and dissipation. This generalization leads to a "finitary" character of the model. It is then combined with the inertial mode theory. The formalism thus obtained allows us to model the rheological behavior of liquids over a wide range of velocity gradients, including the intermediate narrow range corresponding to the Newtonian regime. As experimental tests, viscosity measurements with two kinds of moving rotor rheometers were performed. Only data obtained with liquid water at room temperature are presented and quantitatively analyzed here. It is also shown that liquid n-octane exhibits the same qualitative behaviors as those of liquid water. In the appendices, connection of this theory with quantum mechanics and turbulence phenomena are discussed, and the notion of viscous mass is introduced. [ABSTRACT FROM AUTHOR]

The impact of non-Gaussian height distribution and spectral properties on the lubrication performance of counterformal (point) contacts is quantitatively studied (film parameter, Λ, and asperity load ratio, La) by developing a mixed lubrication model. The Weibull height distribution function and power spectral density (PSD) are used to generate artificial surface topographies (non-Gaussian and Gaussian, isotropic), as these surface topographies are found in many tribological components. The set of variables needed to parametrize and their effect on mixed lubrication is discussed, including the shape parameter, the autocorrelation length, the wavelength ratio, and the Hurst coefficient. It is revealed that a rough surface with a lower shape parameter exhibits higher hydrodynamic lift. The spectral properties (the autocorrelation length and the wavelength ratio) of rough surfaces significantly affect the film parameter and the hydrodynamic and asperity pressures. The film parameter is slightly influenced by the Hurst coefficient.

The Martian magnetosphere is induced, and the low-energy ion escape is related to the extreme ultraviolet (EUV) solar radiation and to the solar wind pressure variations. The ion reflection at the bow shock is a permanent source of ultra-low frequency (ULF) waves. These are convected through the magnetosheath and can penetrate into the upper ionosphere, which can cause additional turbulence at the ionopause which can then cause an enhanced erosion of the ionosphere. Knowing the important role of waves produced in the magnetosheath in the loss processes of the Martian atmosphere, the present study has the aim of making a statistical study of potential cases of wave propagation into the ionosphere of Mars using 14 years of Mars Express (MEX) observations. Data of electron density from the ASPERA-3 and the MARSIS instruments have been used. An enhanced intermittency of ULF waves in Mars magnetosphere was indicated by the kurtosis analysis, which values were higher then 3.0 for all events and on all scales that we investigated. The most energetic frequencies in the ionosphere are in the same range of the main frequencies observed in the magnetosheath. Moderate classification was observed for the most part of the correlations found between ASPERA-3 and MARSIS data. It seems that wave penetration at Mars tends to occur mainly in the descending/maximum solar cycle phase and on the dayside. It was also seen that these events are more frequent in the northern hemisphere Autumn Equinox and during conditions of moderate solar wind pressure. [ABSTRACT FROM AUTHOR]

Germanium films were grown on c-plane sapphire with a 10 nm AlAs buffer layer using molecular beam epitaxy. The effects of Ge film thickness on the surface morphology and crystal structure were investigated using ex situ characterization techniques. The nucleation of Ge proceeds by forming (111) oriented three-dimensional islands with two rotational twin domains about the growth axis. The boundaries between the twin grains are the origin of the 0.2% strain and tilt grains. The transition to a single-grain orientation reduces the strain and results in a better-quality Ge buffer. Understanding the role of thickness on material quality during the Ge(111)/Al2O3(0001) epitaxy is vital for achieving device quality when using group IV material on the sapphire platform.

This paper proposes a physical model–based approach for predicting failures of concrete stormwater pipelines considering corrosion of reinforcing steel bars. Three failure modes, namely flexure failure, shear failure, and cracking failure, were examined over the service life of stormwater pipes based on a widely accepted corrosion model for rebars in concrete. Random stochastic processes were utilized to approximate the load effects in the three failure modes, and the first passage probability theory with the exponential autocorrelation function was employed to conduct the probabilistic analysis over the lifetime of the stormwater pipes. A worked example was presented to demonstrate the application of the proposed approach and evaluate the effect of rebar corrosion on the failure probability of a stormwater pipe. It was found that the correlation lengths of the stochastic processes play a considerable role in the failure probabilities of each failure mode and the system. It was also found that the probability of system failure reduces with an increase in concrete cover thickness and a decrease in water-cement ratio of the concrete. [ABSTRACT FROM AUTHOR]

Copyright of Acta Geoscientica Sinica is the property of Acta Geoscientica Sinica Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Electronic Processing of Materials / Elektronnaya Obrabotka Materialov is the property of Institute of Applied Physics and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The article is dedicated to the search for a biologically motivated mechanism of the cognitive phenomenon of violation of the classical formula of total probability for the disjunction of incompatible events, which is considered by a number of researchers as a quantum-like phenomenon. A classical mechanism implemented by the 6f Fourier holography scheme of the resonant architecture that does not require reference to quantum mechanics either in its physical nature or at the level of formalism is demonstrated. In the analysis, the decision-making is interpreted as a choice of alternatives by using the non-cooperative game "Prisoner's Dilemma". The approach to the task is based on the search for a mechanism for forming a conditional estimate under a condition that contradicts the rule of monotonous decision logic. It is demonstrated that this estimate, in contrast to the unconditional and conditional one with a non-contradictory condition, is formed by logic with exception. The ring architecture of the holographic setup corresponds to the biologically inspired neural network concept of the excitation ring and implements cognitive dissonance on logic with exception. Conditions and ranges of violation of the classical formula of total probability in relation to the correlation radius of the reference image recorded in a hologram storing the monotone logic inference rule are analytically determined. The analytical model is confirmed by a quantitative coincidence of the results of numerical modeling with the published results of natural experiments.

In a technological context where, thanks to the additive manufacturing techniques, even sophisticated geometries as well as surfaces with specific micrometric features can be realized, we propose a mechano-regulation algorithm to determine the optimal microgeometric parameters of the surface of textured titanium devices for biomedical applications. A poroelastic finite element model was developed including a portion of bone, a portion of a textured titanium device and a layer of granulation tissue separating the bone from the device and occupying the space between them. The algorithm, implemented in the Matlab environment, determines the optimal values of the root mean square and the correlation length that the device surface must possess to maximize bone formation in the gap between the bone and the device. For low levels of compression load acting on the bone, the algorithm predicts low values of root mean square and high values of correlation length. Conversely, high levels of load require high values of root mean square and low values of correlation length. The optimal microgeometrical parameters were determined for various thickness values of the granulation tissue layer. Interestingly, the predictions of the proposed computational model are consistent with the experimental results reported in the literature. The proposed algorithm shows promise as a valuable tool for addressing the demands of precision medicine. In this approach, the device or prosthesis is no longer designed solely based on statistical averages but is tailored to each patient's unique anthropometric characteristics, as well as considerations related to their metabolism, sex, age, and more. [Display omitted] • The surface microgeometry of titanium textured device models is optimized. • The optimal surface parameters favoring the best osteointegration were computed. • A mechanobiological model was used to study the device osteointegration. [ABSTRACT FROM AUTHOR]

We report that the stacking order in lyotropic chromonic liquid crystal (LCLC) Sunset Yellow FCF (SSY) is enhanced when incorporated into a cationic hydrogel via the ionic bonds. The chromonic-incorporated gel is initially opaque but transparent and shows a birefringence at high temperatures. The stacking correlation length at room temperature (≈25 °C) is as large as 5.97 nm, corresponding to about 18 molecules in a single stack, and the stacking energy is found to be 7.96 kBT. Both values are larger than those in a normal SSY solution with the respective concentration (≈1 M). [ABSTRACT FROM AUTHOR]

The closure behavior of rock fractures subject to normal loading is essential for deformation analysis of fractured rock masses and the modeling of associated coupled processes. Previous studies have mainly focused on characterizing the closure behavior of mated fractures, and the applicability of existing models to unmated fractures and characteristics of involved parameters have not been comprehensively investigated. We conducted normal loading tests on three tensile granite fractures with different mating degrees by dislocating the fracture surfaces with three offsets. A high-resolution contact model was used to simulate the fracture closure behavior, which was validated by comparing the simulated closure curves and the surface damage areas with experimental measurements. After that, it was applied to simulate the closure behavior for nine numerically generated surfaces with different surface roughness characteristics. The experimental and numerical results exhibit a downward bending trend in the stiffness versus stress curves, which existing models cannot accommodate. An extended hyperbolic model was established by introducing an exponent parameter into the classical Barton–Bandis hyperbolic model, which can better represent the experimental data than previous models. Via regression analysis, we found that the exponent parameter has an approximately constant value of 0.3. The maximum normal displacement is about two times of the mean aperture. The initial stiffness is positively correlated with the elastic modulus and the correlation length and negatively correlated with the mean aperture. Parameters involved in the extended model have precise physical meanings, and they are mathematically predictable based on measurable mechanical and geometrical properties of the rock fractures. Highlights : An extended hyperbolic model for predicting the closure behavior of unmated fractures is developed. The new model accommodates a downward bending trend shown in stiffness-stress curves for unmated fractures. Mathematical correlations between model parameters and fracture mechanical and geometrical properties are established. [ABSTRACT FROM AUTHOR]

CO2 circulated geothermal production can be integrated with CO2 geological sequestration as a utilization method to offset cost. Investigation of heterogeneity impact is limited to CO2 sequestration and its effect on CO2 circulation and associated heat recovery is unclear. This study is aimed to improve the understanding of this problem by numerical experiments. A set of spatially correlated heterogeneous porosity fields is generated using a variety of geostatistical parameters, i.e., variance, correlation lengths, anisotropy and azimuth. Heterogeneous fields of intrinsic permeability and initial/residual water saturation are derived from porosity using equations regressed from a field dataset. Twenty combinations of injection pressure and well space obtained by Latin-Hypercube sampling are deployed in each heterogeneous field, generating a suite of numerical geothermal reservoir models. Performance indicators, including lifespan, net stored CO2, produced heat flux, and total recovered heat energy in lifespan, are calculated from each model simulation. The simulation results suggest that geologic heterogeneity could develop highpermeable CO2 flow paths, causing bypass of the hot low-permeable zones, shortened lifespan and reduced total recovered heat energy. Depending on the azimuth, anisotropy can create either flow barriers or preferential flow paths, increasing or decreasing heat sweeping efficiency. The relative angle between horizontal wells and the axis of maximum continuity of the heterogeneity can be optimized to maximize heat recovery efficiency. These finds provide useful insights of interplay between geological heterogeneity, well placement and operation of CO2 circulated geothermal production. [ABSTRACT FROM AUTHOR]

A drain current local variability compact model due to random fluctuation of channel length induced by line edge roughness/line width roughness (LER/LWR) is derived here. The random fluctuation of channel length leads to correlated fluctuations of threshold voltage and effective mobility of the current carriers. Therefore, an unified compact model is required to combine all the causes. Our model is based on the principle of propagation of variance. For the model verification purpose, calibrated technology computer aided design (TCAD) simulation platform is extensively used for all possible bias regions and several LER profile parameters. Channel profile optimization is critically studied with respect to different LER parameters, aiming reduction of ID variability. The model is further extended for SOI (Silicon-on-insulator) transistor and validated with literature data of threshold voltage and on-current variability. [ABSTRACT FROM AUTHOR]

Soil surface roughness (SSR) plays an important role in the physical and hydrological processes of soil surfaces. In order to achieve nondestructive, fast, and large area measurement of SSR, unmanned aerial vehicle (UAV) photogrammetry method was used to take digital images at the altitude of 10 m on three plots and generated the digital elevation model for calculating SSR. From the results of UAV-based SSR, the following conclusions were obtained. First, the domain of soil surface height was consistent with the designed height of the three plots: smooth (all pixels: −5.5–6.5 cm and 80% pixels: −2.3–2.3 cm) < medium (all pixels: −8.5–8.5 cm and 80% pixels: −3.4–3.4 cm) < rough (all pixels: −16.0–13.0 cm and 80% pixels: −6.8–6.8 cm). Second, UAV-based SSR can represent their differences among the three plots, indicated by a consistent root-mean-square height (rmsh) and correlation length (cl) with the pin-profiler results. Third, UAV-based SSR results can reveal the anisotropy of SSR, and for the medium plot, the maximum variation of rmsh and cl with observed azimuth angle is 0.77 cm and 14.35 cm, respectively. The UAV-based SSR method has the advantages of low cost, high efficiency, and all-directional measurement, and can be used in remote sensing model and hydrological simulation.

Understanding the effects of polar nanoregions (PNRs) dynamics on dielectric properties is a complex question of essential importance for both fundamental studies of relaxor ferroelectrics and their applications to electro-optic devices. The frequency dependence of dielectric response to the bias electric field opens a brand new window for the study of this problem. A novel model from mesoscopic to macroscopic, revealing the relationship between the dielectric permittivity to the applied electric field, temperature, and PNRs, was established based on mean field approximation and the theory of continuum percolation, and not only validates the field-induced percolation and the relaxation time divergency at the freezing temperature, but also predicts the frequency dependence of dielectric response. Unexpectedly, the model reveals the field-enhanced correlation length results in the nonmonotonic behavior of dielectric response, and implies that the increased orientation consistency of dipolar clusters and coercive fields originated from inherent inhomogeneity slow down the relaxation time of PNR reorientation. Considering the multi-scale heterogeneity of PNRs in relaxor, we found that the increased heterogeneity degree reduces the dielectric permittivity, but changes the slope of dielectric response to the bias electric field. [ABSTRACT FROM AUTHOR]

This paper uses the spectral stochastic finite element method (SSFEM) for analyzing reinforced concrete (RC) beam/slab problems. In doing so, it presents a new framework to study how the correlation length of a random field (RF) with uncertain parameters will affect modeling uncertainties and reliability evaluations. It considers: 1) different correlation lengths for uncertainty parameters, and 2) dead and live loads as well as the elasticity moduli of concrete and steel as a multi-dimensional RF in concrete structures. To show the SSFEM's efficiency in the study of concrete structures and to evaluate the sensitivity of the correlation length effects in evaluating the reliability, two examples of RC beams and slabs have been investigated. According to the results, the RF correlation length is effective in modeling uncertainties and evaluating reliabilities; the longer the correlation length, the greater the dispersion range of the structure response and the higher the failure probability. [ABSTRACT FROM AUTHOR]

Hydrogen induced plasticity has been found in metallic glasses; however, the underlying mechanism remains unclear. Herein, we studied a Cu-Zr metallic glass charged in a hydrogen atmosphere inside an environmental transmission electron microscope. Compression tests of hydrogen charged nanopillars show more controllable deformation compared to uncharged ones. A variable resolution fluctuation electron microscopy study of the hydrogen charged samples reveals an increase in the correlation length of the medium-range order. Our results provide experimental evidence for hydrogen-induced heterogeneity and support the idea that increasing the degree of heterogeneity leads to multiple local shear events and suppresses catastrophic shear banding. IMPACT STATEMENT Direct evidence of an increase in the spatial correlation length of the medium-range order is found during hydrogen charging of a Cu-Zr metallic glass and leads to enhanced plastic deformation.

A 6f-scheme of Fourier holography with resonant architecture is considered, which implements memory replenishment with new information that contradicts the previously recorded. It is shown that the low-frequency attenuation due to the nonlinearity of the exposure characteristics of holographic recording media in the initial reference holographic image recorded in a narrow filtering range corresponding to the degradation in the correlation plane of the global maximum of the autocorrelation function below the lateral maxima leads to the response instability – an intermittent mode. It is shown that the intermittent mode corresponds to the restructuring of the autocorrelation function of a composite standard recorded in holograms from one range of values of the approximation model parameters to another. It is shown that the correlation length of the composite image recorded in holograms is an order parameter of the system; its rapid change precedes the loss of response stability and the transition to an unstable regime with intermittency. The results of numerical simulation are presented.

We present a systematic experimental dataset on the temperature dependence of specific heat capacity in a binary mixture of the second and seventh homologous series of 5-alkyloxy-2-(4-nonyloxy-phenyl) pyrimidine (PhP) liquid crystal compound. These binary mixtures exhibit nematic, smectic-A, and smectic-C phases within a concentration range of x = 0-0.45. The liquid crystalline phases are structurally characterized using synchrotron x-ray diffraction. We determine the apparent molecular length in the nematic phase, smectic layer spacing, average distance between the long axes of molecules, correlation length, and orientational order parameters (< PhP1 = 0-0.45. The liquid crystalline phases are structurally characterized using synchrotron x-ray diffraction. We determine the apparent molecular length in the nematic phase, smectic layer spacing, average distance between the long axes of molecules, correlation length, and orientational order parameters (< P 2 > and < P 4 >) as functions of temperature. The tilt angle in the SmC phase is inferred from the layer spacing data. To examine the critical behavior near the nematic to smectic A (NA) and smectic A to the smectic C (AC) phase transitions, we evaluate the critical exponents: α from specific heat capacity, β from the fitting of the temperature-dependent tilt angle, and ν ǁ , ν ⊥ from the temperature-dependent longitudinal ( ξ ǁ ) and transverse ( ξ ⊥ ) correlation lengths. Modulated Differential Scanning Calorimetry (MDSC) measurements indicate the absence of phase shift, latent heat and imaginary specific heat capacity, suggesting that the AC transitions are second-order for all binary mixtures. The results obtained from heat capacity reveal that both the AC and NA transitions exhibit non-universal behaviors with effective exponents lying between the tricritical and 3D-XY values and follow nearly identical curve with decreasing width of the Sm-A and N phases. The Josephson hyper scaling relation is verified for both the NA and AC transitions in different mixtures. Moreover, knowing the heat capacity critical exponent α and the order parameter critical exponent β , the susceptibility critical exponent γ for the AC transition can be estimated from Rushbrooke equality α + 2 β + γ = 2, with γ values ranging from 1.015 to 1.313, indicating the system's crossover character and apparently validating the Rushbrooke equality., (© 2024 IOP Publishing Ltd. All rights, including for text and data mining, AI training, and similar technologies, are reserved.)

Lead-borate glasses manifest unique structure with lead oxide composition owing to their dual role of modifier and former. The medium-range signature from the first sharp diffraction peak (FSDP) in lead-borates exhibits substantial correlations due to the presence of superstructural units. Pressure plays an important role in altering bonding characteristics and hence structure in materials. To understand pressure-induced changes in the medium-range order (MRO) in lead-borate glasses, we have carried out high pressure X-ray diffraction studies in the FSDP region of these glasses up to 25 GPa. Two clear peaks, q0 and q1 are observed in all the modified glasses, below and above the position of the FSDP in pure B2O3 glass. This shows that lead oxide alters the FSDP and causes changes in the network structure at the MRO. q1 exhibits an increase under compression, resulting in a reduction in correlation lengths for all glass compositions. The initial steep decrease is accompanied by a lower rate of reduction at higher pressures. This shows that correlations arising from structural voids in the boron matrix exhibit similar decrease for various lead oxide compositions. [ABSTRACT FROM AUTHOR]

Toe cutting of hillslopes that are intended for the expansion of the transportation networks across the hilly regions need to follow an engineered basis to avert catastrophic failures. The commonly utilized deterministic Limit Equilibrium Method (LEM) does not incorporate the uncertainties in geotechnical properties and might exhibit inappropriate or erroneous consequences of toe excavation. In order to highlight the chances of toe-excavation induced slope failures, this paper reports the outcomes of the probabilistic stability analysis while considering one-dimensional spatial variability of soil shear strength parameters. The importance of such probabilistic analyses is established by finding that 79% of the toe-excavated slopes, which are judged safe from deterministic analysis, actually exhibit high probabilities of failure. Further, the influences of coefficient of variation (CoV) and the correlation between the shear strength parameters are also highlighted. The probability of failure of the cut slopes is found to be decreased by around 70% when the correlation coefficient of the shear strength parameters decreased from +0.5 to −0.5. The permissible width of toe excavation is found to be governed by the indicators of spatial variability. It is revealed that for a CoV value of 0.2 and 0.3, a maximum horizontal extent of 7 m and 5 m can be excavated without leading to slope failure for a dimensionless correlation length up to 0.2 and 0.1, respectively. [ABSTRACT FROM AUTHOR]

An active–passive microwave retrieval algorithm for simultaneous determination of soil surface roughness parameters [vertical root-mean-square (RMS) height (${s}$) and horizontal correlation length (${l}$)] is presented for bare soils. The algorithm is based on active–passive microwave covariation, including the improved Integral Equation Method (I2EM), and is tested with global soil moisture active passive (SMAP) observations. The estimated retrieval results for ${s}$ and ${l}$ are overall consistent with values in the literature, indicating the validity of the proposed algorithm. Sensitivity analyses showed that the developed roughness retrieval algorithm is independent of permittivity for ${\varepsilon }_{s} > 10$ [-]. Furthermore, the physical model basis of this approach (I2EM) allows the application of different autocorrelation functions (ACF), such as Gaussian and exponential ACFs. Global roughness retrieval results confirm bare areas in deserts such as Sahara or Gobi. However, the type of ACF used within roughness parameter estimation is important. Retrieval results for the Gaussian ACF describe a rougher surface than retrieval results for the exponential ACF. No correlations were found between roughness results and the amount of precipitation or the soil texture, which could be due to the coarse spatial resolution of the SMAP data. The extension of this approach to vegetated soils is planned as an add-on study. [ABSTRACT FROM AUTHOR]

Soil properties vary in space even within a soil layer. Nevertheless, site response analyses are typically conducted using a best-characterized shear wave velocity (Vs) profile without considering its fluctuation. In this study, the random field theory is adopted to model heterogeneous Vs profiles for a range of coefficient of variations (COVs) and correlation lengths (CLs). Linear 1D site responses are analyzed with the randomized profiles to quantify the influence of spatial Vs variation on the propagated ground motions. Results reveal that a higher COV of randomized Vs profiles leads to a lower mean ground response compared with a homogeneous Vs profile. The variation of CL does not significantly affect the surface response and peak ground acceleration profile, but is shown to influence the degree of fluctuation of the maximum shear strain profiles. For idealized profiles, the effect of heterogeneous Vs on ground response can be approximately predicted by using reduced Vs and enlarged small strain damping that are dependent on COV. [ABSTRACT FROM AUTHOR]

Electric resistivity, specific heat, magnetic susceptibility, and inelastic neutron scattering experiments were performed on a single crystal of the heavy fermion compound Ce(Ni0.935Pd0.065)2Ge2 in order to study the spin fluctuations near an antiferromagnetic (AF) quantum critical point (QCP). The resistivity and the specific heat coefficient for T ⩽ 1 K exhibit the power law behavior expected for a 3D itinerant AF QCP (ρ(T) ∼ T(3/2) and γ(T) ∼ γ0 - bT(1/2)). However, for 2 ⩽ T ⩽ 10 K, the susceptibility and specific heat vary as log T and the resistivity varies linearly with temperature. Furthermore, despite the fact that the resistivity and specific heat exhibit the non-Fermi liquid behavior expected at a QCP, the correlation length, correlation time, and staggered susceptibility of the spin fluctuations remain finite at low temperature. We suggest that these deviations from the divergent behavior expected for a QCP may result from alloy disorder.