Directional Effects Research Articles

Study on the influence of base shear distribution on the seismic response of base-isolated split-foundation structures

ABSTRACT Split-foundation structures with base isolation have multiple isolation layers due to their uneven foundation heights. This complexity adds challenges to the seismic isolation design of split-foundation structures. In this paper, two special parameters, namely the shear non-uniformity factor Φ and the ratio of shear non-uniformity factor Γ, were proposed. Response spectrum analysis and time history analysis on base-isolated split-foundation structures with varying Φ and Γ were conducted to investigate their seismic response and damping effect. The results indicate that Φ primarily affects the seismic response in the lower stories and the upper embedding story. When Φ is too small or too large, it results in an uneven isolation effect. Moreover, when the base shear ratio β z exceeds 0.5, the distribution of plastic hinges is significantly affected by the variations in Φ. Additionally, the story shear and story drift ratio of lower stories in the along-slope direction are generally greater than that of the corresponding story of the non-isolated structure. Therefore, in the seismic isolation design of the split-foundation structure, the base shear at different embedding ends should be reasonably assigned. Special attention should also be given to the adverse effects in the along-slope direction.

Influence mechanism of the diameter of the energy accumulation hole on the bi-directional cumulative tension blasting

This study focuses on evaluating the influence of the energy accumulation hole diameter on bi-directional cumulative tension blasting. Firstly, the penetration depth of bi-directional cumulative tension blasting is determined, followed by an analysis of the corresponding fracture mechanics behavior. Secondly, the Smooth Particle Hydrodynamics (SPH) method is used for numerical analysis of the bi-directional cumulative tension blasting process, and the Johnson-Holmquist constitutive model is then employed to examine the dynamic process during tensile blasting-induced cracking. This analysis provides insights into damage development, particle distribution, stress distribution, and crack propagation in the rock at different opening diameters. The findings reveal that, except for the 2 mm case, bi-directional cumulative tension blasting effectively produces directional cracks aligned with the energy accumulation direction. For hole diameters between 4–8 mm, linear through cracks form in the energy accumulation direction. However, a 2 mm diameter opening only generates short shear cracks around the blast hole. With energy accumulation hole diameters ranging from 10–14 mm, the crack propagation depth is insufficient for complete penetration, despite the presence of linear cracks in the energy accumulation direction. When diameter exceeds 14 mm, symmetrical airfoil cracks appear in non-concentrated energy directions, with larger diameters resulting in shorter crack propagation lengths. During the directional cracking process for hole diameters of 4–8 mm, explosive particles facilitate crack expansion in width and length through the action of a “gas wedge.” On-site blasting tests confirm the excellent directional pre-splitting effect of bi-directional cumulative tension blasting.

Potential drug targets for gastroesophageal reflux disease and Barrett's esophagus identified through Mendelian randomization analysis.

Gastroesophageal reflux disease (GERD) is a prevalent chronic ailment, and present therapeutic approaches are not always effective. This study aimed to find new drug targets for GERD and Barrett's esophagus (BE). We obtained genetic instruments for GERD, BE, and 2004 plasma proteins from recently published genome-wide association studies (GWAS), and Mendelian randomization (MR) was employed to explore potential drug targets. We further winnowed down MR-prioritized proteins through replication, reverse causality testing, colocalization analysis, phenotype scanning, and Phenome-wide MR. Furthermore, we constructed a protein-protein interaction network, unveiling potential associations among candidate proteins. Simultaneously, we acquired mRNA expression quantitative trait loci (eQTL) data from another GWAS encompassing four different tissues to identify additional drug targets. Meanwhile, we searched drug databases to evaluate these targets. Under Bonferroni correction (P < 4.8 × 10-5), we identified 11 plasma proteins significantly associated with GERD. Among these, 7 are protective proteins (MSP, GPX1, ERBB3, BT3A3, ANTR2, CCM2, and DECR2), while 4 are detrimental proteins (TMEM106B, DUSP13, C1-INH, and LINGO1). Ultimately, C1-INH and DECR2 successfully passed the screening process and exhibited similar directional causal effects on BE. Further analysis of eQTLs highlighted 4 potential drug targets, including EDEM3, PBX3, MEIS1-AS3, and NME7. The search of drug databases further supported our conclusions. Our study indicated that the plasma proteins C1-INH and DECR2, along with 4 genes (EDEM3, PBX3, MEIS1-AS3, and NME7), may represent potential drug targets for GERD and BE, warranting further investigation.

Experimental Study on the Directional Effect of Damage in Marble Under Different Impact Modes

Experimental Study on the Directional Effect of Damage in Marble Under Different Impact Modes

Associations between serum per- and polyfluoroalkyl substances as mixtures and lipid levels: A cross-sectional study in Jinan

Per- and polyfluoroalkyl substances (PFASs) are known to be linked with dyslipidemia. Between March and June 2022, we collected 575 fasting serum samples from individuals without occupational exposure in Jinan, China. Eighteen PFASs were analyzed using UHPLC-Orbitrap MS. Multiple linear regression (MLR), Bayesian kernel machine regression (BKMR), and Quantile g-computation (QGC) models were utilized to assess the effects of both individual PFAS and PFAS mixtures on serum lipid levels, including triglycerides (TG), cholesterol (CHO), high-density lipoprotein (HDL), and low-density lipoprotein (LDL). The PFAS mixture, composed of perfluoroheptanoic acid (PFHpA), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluoroundecanoic acid (PFUnDA), perfluorododecanoic acid (PFDoDA), perfluorotridecanoic acid (PFTrDA), perfluorohexane sulfonate (PFHxS), perfluoroheptane sulfonic acid (PFHpS), perfluorooctane sulfonate (PFOS), and 6:2 chlorinated polyfluoroalkyl ether sulfonate (6:2 Cl-PFESA), showed a positive association with CHO and LDL levels, while no distinct trend was noted in HDL and TG levels about changes in PFAS mixtures levels in BKMR and QGC models, adjusted for gender, age, BMI, occupation, and educational level. The effects of individual PFASs on lipid levels were in general consistent across MLR, BKMR and QGC models. PFUnDA and PFTrDA demonstrated greater impacts on blood lipid levels compared to other PFAS, albeit with varied directional effects. Age-stratified analysis revealed PFAS mixture effect was more pronounced in participants aged higher than 40. No obvious trend in lipid levels with changes in PFAS mixture levels in participants with age ranged from 18 to 40, while positive association between PFAS mixture and CHO and LDL was detected in participants aged higher than 40.

Thermal diffusion and microstructural evolution of Cu-Zn binary system under hypergravity

It has long been a common assumption that the stress conditions for materials operating in hypergravity could be simplified to traditional stress conditions. However, such simplification has not been experimentally verified. In this study, we examined the thermal diffusion and microstructural evolution of the Cu-Zn binary system under hypergravity levels of up to 4700 g (g: gravity of Earth, 9.8 m/s2). Our findings revealed distinct differences when compared to the behaviour of the materials under traditional stress. Under hypergravity, we observed an enhancement in interfacial diffusion of atoms up to 3500 g, and this enhancement was suppressed under 4700 g hypergravity. Additionally, a directional effect was observed, where the diffusion layer formed in hypergravity from Cu to Zn direction was thicker than that formed under the opposite direction of hypergravity. Furthermore, the reduction of dislocations in the diffusion layer was observed as the hypergravity increased. The study suggests that the hypergravity-induced centrifugal force (Fg) and buoyancy force (Fb) significantly influence the diffusion characteristics of the Cu-Zn binary system. Fg enhances interfacial contact and promotes interfacial diffusion, while Fb promotes the diffusivity of vacancies, and thereby atoms, contributing to the observed directional effects. These factors ultimately lead to the formation of a biphasic phase and the suppression of precipitation under hypergravity. Additionally, as the hypergravity increases, defects/vacancies reduce, resulting in the suppression of diffusion. Our findings provide valuable insights into the diffusion and microstructural evolution of materials under hypergravity conditions.

Experimental and Numerical Investigation of Effect of Inclination on sCO2 Heat Transfer in a Circular Pipe

Abstract Supercritical carbon dioxide (sCO2) can be utilized as a working fluid in various thermal systems including large-scale power cycles; portable power production units, centralized coolant systems, and standalone cooling devices. However, the lack of accurate prediction tools such as heat transfer coefficient correlations and insufficient research studies about the mechanisms controlling heat transfer processes are hindering its practical realization for key energy and cooling systems. The overall objective of this study is to extend fundamental knowledge about heat transfer and fluid dynamic processes in conduits pertinent to sCO2 with an emphasis on flow direction and inclination effects. This paper presents the study on effects of gravity, buoyancy on sCO2 flow at temperatures near and away from the pseudo-critical temperature. The experimental setup consists of a high temperature and pressure sCO2 heat transfer loop and flow testing facility. Recently, researched sCO2 heat exchangers can have tubes oriented at different angles such as 45 deg or 90 deg to horizontal. For optimized design of efficient and cost-effective turbomachinery components utilizing sCO2 as the heat transfer fluid, an understanding of convective heat transfer inside a tube/pipe is equally as important as external heat transfer. This paper presents an experimental and numerical study on sCO2 heat transfer at various inclinations with angles ranging from 0 deg (horizontal) to 90 deg (vertical) along with upward and downward flow direction with different inlet temperatures. Thermocouple-based temperature measurement is utilized at multiple locations within the test section axially and circumferentially to study the temperature distributions on the tube surface. Computational fluid dynamics (CFD) simulations have been performed using ANSYS Fluent to complement experimental data. The CFD and experiment have been analyzed against the well-known Gnielinski Nusselt number correlation.

Psoriasis may increase the risk of idiopathic pulmonary fibrosis: a two-sample Mendelian randomization study

BackgroundAlthough some studies have indicated that Psoriasis could contribute to the risk of idiopathic pulmonary fibrosis (IPF), no study has reported a clear causal association between them. Our aim was to explore the potential relationship between Psoriasis and IPF using Mendelian randomization (MR) design.MethodsTo explore a causal association between Psoriasis and IPF, we used genetic instruments from the largest available genome-wide association study (GWAS) of European ancestry, including psoriasis (5314 cases, 457,619 controls) and IPF (1028 cases, 196,986 controls). Our main analyses were conducted by inverse-variance weighted (IVW) method with random-effects model, with the other complementary four analyses: weighted median method, weighted mode, multivariable MR and MR-Egger approach.ResultsThe results of IVW methods demonstrated that genetically predicted psoriasis was significantly associated with higher odds of IPF, with an odds ratio (OR) of 1.09 (95%CI, 1.01–1.18; P = 0.02). Weighted median method, weighted mode and multivariable MR also demonstrated directionally similar results (P < 0.05), while the MR-Egger regression did not reveal the impact of psoriasis on IPF (OR = 1.09, 95%CI, 0.98–1.21; P = 0.11). In addition, both funnel plots and MR-Egger intercepts indicated no directional pleiotropic effects between psoriasis and IPF.ConclusionsOur study provided potential evidence between genetically predicted psoriasis and IPF, which suggests that understanding the mutual risk factors between psoriasis and IPF can facilitate the clinical management of both diseases.

Silver Nanowires Cascaded Layered Double Hydroxides Nanocages with Enhanced Directional Electron Transport for Efficient Electrocatalytic Oxygen Evolution.

Designing and fabricating highly efficient oxygen evolution reaction (OER) electrocatalytic materials for water splitting is a promising and practical approach to green and sustainable low-carbon energy systems. Herein, a facile in situ growth self-template strategy by using ZIF-67 as a consumable layered double hydroxides (LDHs) template and silver nanowires (AgNWs) as 1D conductive cascaded substrate to controllably synthesize the target AgNWs@CoFe-LDH composites with unique hollow shell sugar gourd-like structure and enhanced directional electron transport effect is reported. The AgNWs exhibit the key functions of the close connection of CoFe-LDH nanocages and the support of the directional electron transport effect in the composite catalyst inducing electrons directionally moving from CoFe-LDH to AgNWs. Meanwhile, the CoFe-LDH nanocages with ultrathin nanosheets and hollow structural properties show abundant active sites for electrocatalytic oxygen generation. The versatile AgNWs@CoFe-LDH catalyst with optimized components, enhanced directional electron transport, and synergistic effect achieves high OER performance with the overpotential of 207 mV and long-term 50 h stability at 10 mA cm-2 in an alkaline medium. Moreover, in-depth insights into the microstructure, structure-activity relationships, identification of key intermediate species, and a proton-coupled four-electron OER mechanism based on experimental discovery and theoretical calculation are also demonstrated.

Comparison of Effects of Balance Training Exercise and Gaze Stability Exercises on Balance and Postural Control in Elderly With Fall Risk: A Randomized Controlled Trial

Aim To compare the changes in outcomes of balance and postural control after balance training exercise and gaze stability exercise in the elderly population with fall risk. Methods After the screening process, 44 subjects were randomized into three groups: Experimental Group A (Balance training exercises, BTE); Experimental Group B (Gaze stability exercises, GSE), and Control Group C (Fall prevention education only). The outcome measures were center of pressure (COP) range, COP sway, reaction time, proprioception, static balance, Clinical Test for Sensory Interaction in Balance (CTSIB), and Short Falls Efficacy Scale (SFES). The pre and post-data were recorded at baseline and after 8 weeks. The normality of the distribution was assessed using the Shapiro-Wilk test. Demographic data and baseline measures were compared using one-way ANOVA considering group as between factor and mixed model ANOVA was used to find out the group effect and time effect and time × group interaction effect. Statistical significance was indicated if p ≤ 0.05. Results GSE had significant changes only in CTSIB 4 whereas BTE had significant changes in CTSIB 4, 5, and 6. COP range showed a significant time effect in the front direction (p = 0.02). For proprioception, there was a significant time effect in the left (p = 0.018) and right direction (p = 0.005), whereas changes in front and back directions were found to be insignificant. SFES showed a significant time effect (p < 0.001), group effect (p = 0.21), and time × group interaction effect (p < 0.001). Conclusion Balance training exercises may be a more effective form of intervention to improve balance and postural control in the elderly population.

Effects of Burial Furrow Parameters on Soil Water Movement under Subsurface Stalk Composite Pipe Irrigation

Stalk composite pipe (SCP), a novel product used for subsurface irrigation, is primarily composed of crop stalks, soil, and water. In subsurface SCP irrigation (SSI), comprehending the effects of burial furrow parameters on soil water movement is critical. However, the precise effects are not known. Here, we aimed to assess the effects of varying burial furrow dimensions, including widths of 15, 20, and 25 cm, depths of 10, 15, and 20 cm, and backfilling-soil bulk densities of 1.1, 1.2, and 1.3 g cm−3, on wetted distance and soil water movement. We conducted an indoor soil bin experiment and numerical simulation using HYDRUS-2D in 2020–2021 in Zhengzhou City, Northern China. Wider burial furrows resulted in increased wetted distance and soil water content, ultimately leading to greater effect in a horizontal direction. In the horizontal profile, the average soil water content of the SSI treatments, which used burial furrow widths of 15, 20, and 25 cm, were 1.121, 1.230, and 1.280 times higher, respectively, than those of CK. The burial furrow depth had minimal effect on the wetted distance, whereas adjusting the burial furrow depth primarily affected the saturation depth. The speed of wetting-front migration was affected by the backfilling-soil bulk density. For a given soil and crop, it is advisable to determine first the burial furrow width and backfilling-soil bulk density. Subsequently, the burial furrow depth should be established based on the distribution of the crop’s roots. Our findings offer a scientific basis for using SSI.

Pengaruh Akuntabilitas, Transparansi, Partisipasi Masyarakat terhadap Pengelolaan Dana Desa: Studi Kasus pada Pemerintah Desa Kecamatan Nasal Kabupaten Kaur Provinsi Bengkulu

This study was conducted to determine whether accountability, transparency and community participation have an influence on Village Fund Management in the Village Government of Nasal District 2023. The analysis tool in this research uses the help of the SmartPLS software program version 4.0 which consists of evaluating the outer model and inner model. This research is included in descriptive research and is clauseal. The population in this study is the Village Government of Nasal District. Sampling in this study used Nonprobability sampling technique with saturated sampling method so that 85 respondents were obtained from all village officials at the Nasal District Village Government. The results show that accountability has a significant effect in a positive direction on village fund management in the Village Government of Nasal District, Kaur Regency in 2023. Transparency has a significant effect in a positive direction on the management of village funds in the Village Government of Nasal District, Kaur Regency in 2023. Community participation has a significant effect in a positive direction on the management of village funds in the Village Government of Nasal District, Kaur Regency in 2023.

The SMILE Effect in the Beam Propagation Direction Affects the Beam Shaping of a Semiconductor Laser Bar Array

Near-field bending of a laser diode bar (i.e., the SMILE effect) degrades the laser beam brightness, adversely affecting optical coupling and beam shaping. Previous reports mainly focused on the two-dimensional near-field bending of a laser diode bar. However, the near-field bending of a laser diode bar not only occurs in the laser bar growth direction, but also in the beam propagation direction. The present article proposes the three-dimensional near-field bending of a laser diode array, which is commonly known as the three-dimensional spatial SMILE effect. Through theoretical and simulated investigations, it has been found that a laser bar array not only deforms in the fast axis direction to cause the traditional two-dimensional SMILE effect but also experiences an additional deformation of approximately 2 μm in the laser emission direction simultaneously. Due to the SMILE effect in the beam propagation direction, not all emitters are aligned in a straight line, and some emitters experience defocusing during collimation. Consequently, there is an increase in the residual divergence angle and beam width, resulting in a degradation of the laser bar array’s beam quality. According to the theoretical calculations, ZEMAX simulations, and experimental results, for a FAC (fast axis collimation) with a focal length of 300 μm, the divergence angle of single emitter after collimating in the fast axis increases from 4.95 mrad to 6.46 mrad when the offsetting of the working distance between the incident beam waist and FAC lens increases from 0 μm to 2 μm.

Analysis of faulting destruction and water supply pipeline damage from the first mainshock of the February 6, 2023 Türkiye earthquake doublet

In 2023, two consecutive earthquakes exceeding a magnitude of 7 occurred in Türkiye, causing severe casualties and economic losses. The damage to critical urban infrastructure and building structures, including highways, railroads, and water supply pipelines, was particularly severe in areas where these structures intersected the seismogenic fault. Critical infrastructure projects that traverse active faults are susceptible to the influence of fault movement, pulse velocity, and ground motions. In this study, we used a unique approach to analyze the acceleration records obtained from the seismic station array (9 strong ground motion stations) located along the East Anatolian Fault (the seismogenic fault of the MW7.8 mainshock of the 2023 Türkiye earthquake doublet). The acceleration records were filtered and integrated to obtain the velocity and displacement time histories. We used the results of an on-site investigation, jointly conducted by China Earthquake Administration and Türkiye’s AFAD, to analyze the distribution of PGA, PGV, and PGD recorded by the strong motion array of the East Anatolian Fault. We found that the maximum horizontal PGA in this earthquake was 3.0 g, and the maximum co-seismic surface displacement caused by the East Anatolian Fault rupture was 6.50 m. As the fault rupture propagated southwest, the velocity pulse caused by the directional effect of the rupture increased gradually, with the maximum PGA reaching 162.3 cm/s. We also discussed the seismic safety of critical infrastructure projects traversing active faults, using two case studies of water supply pipelines in Türkiye that were damaged by earthquakes. We used a three-dimensional finite element model of the PE (polyethylene) water pipeline at the Islahiye State Hospital and fault displacement observations obtained through on-site investigation to analyze pipeline failure mechanisms. We further investigated the effect of the fault-crossing angle on seismic safety of a pipeline, based on our analysis and the failure performance of the large-diameter Thames Water pipeline during the 1999 Kocaeli earthquake. The seismic method of buried pipelines crossing the fault was summarized.

Spin Waves in Ferromagnetic Nanorings with Interfacial Dzyaloshinskii–Moriya Interactions: II. Directional Effects

Spin Waves in Ferromagnetic Nanorings with Interfacial Dzyaloshinskii–Moriya Interactions: II. Directional Effects

Holographic Schwinger effect in anisotropic media

According to gauge/gravity correspondence, we study the holographic Schwinger effect within an anisotropic background. Firstly, the separate length of the particle–antiparticle pairs is computed within the context of an anisotropic background which is parameterized by dynamical exponent ν\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\ u $$\\end{document}. It is found that the maximum separate length x increases with the increase of dynamical exponent ν\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\ u $$\\end{document}. By analyzing the potential energy, we find that the potential barrier increases with the dynamical exponent ν\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\ u $$\\end{document} at a small separate distance. This observation implies that the Schwinger effect within an anisotropic background is comparatively weaker when contrasted with its manifestation in an isotropic background. Finally, we also find that the Schwinger effect in the transverse direction is weakened compared to the parallel direction in the anisotropic background, which is consistent with the top-down model.

An advanced three-dimensional analytical model for wind turbine near and far wake predictions

Most existing analytical wake models have been designed to represent the velocity distribution of the far wake region behind a wind turbine, but fail to reproduce the trend of the near wake. In order to meet the demand for both near and far wake velocity predictions, a concise three-dimensional dual-cosine shape (3D-COU) model is proposed. Moreover, by taking into account the wind shear and ground effects in the vertical direction, this model is capable of describing the anisotropic property of the 3-D wake field and is much closer to the reality. The proposed model is then calibrated and validated through a series of test cases, including different scales of turbines that are operating under a wide range of inflow conditions, and meanwhile the reference data resource is diverse. Overall, the results demonstrate that the 3D-COU model can accurately predict the variations of the wake velocity in both the vertical and horizontal directions throughout the whole wake region. Given its good accuracy, simplicity and applicability, this model provides the potential to effectively address practical problems in wind energy projects.

Retrieving land surface reflectance anisotropy with Sentinel-3 observations and prior BRDF model constraints

Sentinel-3 supports governmental policies and European programmes such as the Copernicus Global Land Service with daily monitoring of the land surface by measuring the Earth's surface with its multi-band wide-swath visible and near-infrared radiometers. To fully exploit Sentinel-3 data sets, performing a correction of directional effects caused by the land surface reflectance anisotropy properties is mandatory. This correction requires first an estimation of the bidirectional reflectance distribution function (BRDF) to be properly achieved. The quality and robustness of global estimates of key land surface variables derived from space-borne sensors depend clearly on an accurate assessment of the spectral BRDF.Here, we present an algorithm aiming at harnessing the Sentinel-3's wide imaging swath to retrieve the land surface BRDF, approximating it via a kernel-driven semi-empirical model which can then be used to normalise the observations to a common Sun-sensor geometry. Our algorithm, named ReBeLS (Regularised BRDF inversion for Land Surface), uses a temporally regularised BRDF inversion approach and, together with prior knowledge of the land surface BRDF obtained from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensors, assimilates Sentinel-3 surface reflectance observations. We focus on the results derived from observations provided by the Sentinel-3 Ocean and Land Colour Instrument (OLCI) sensors; however, the algorithm can also be applied to reflectance observations acquired by the Sea and Land Surface Temperature Radiometer (SLSTR). The retrieved BRDF model parameters reproduce within uncertainties the directional signature as seen by the Visible Infrared Imaging Radiometer Suite (VIIRS) sensor. The generated Sentinel-3 normalised surface reflectance products are a significant advance compared with time series of directional surface reflectance and maximum value composite images, showing a statistically significant (p≪0.05) correlation (r>0.9) with VIIRS nadir BRDF-adjusted surface reflectance. Furthermore, the ReBeLS Sentinel-3 BRDF products offer enough flexibility to allow users to compute spectral surface albedos or to normalise surface reflectance to any Sun-sensor configuration.

Nonreciprocal Intelligent Soundproof Barrier with Active Nonlocal Acoustic Metastructure

Sound insulation is an important issue in daily life and has applications in various scenarios. Conventional acoustic passive metamaterial barriers are designed as a reciprocal sound insulation. However, for some specific application scenarios, unidirectional acoustic insulation is required, which is an enormous challenge for breaking the reciprocity of sound transport with conventional passive metamaterials. Here, a soundproof barrier with nonlocal acoustic metastructure is proposed, which consists of a microcontroller to connect a pair of spatially separated microphones and speakers, to tailoring the acoustic wave transmission for realizing nonreciprocal acoustic insulation. The theoretical calculation and experiment measurement indicated that the active acoustic barrier with a selectable working frequency can realize the suppressive effect in one direction and the enhancive effect in the other direction for an incident acoustic signal. Particularly, the function of an active soundproof barrier can be freely switched to forward, backward, and bidirectional sound insulation by tailoring the nonlocal distance of the digital meta‐atom. Furthermore, this acoustic metastructure is extended from a one‐dimentional waveguide to a two‐dimentional plane to illustrate that it is still valid in an open‐field environment. The proposed customizable nonreciprocal soundproof barriers provide an avenue for many applications in the specific scenarios that require unidirectional sound insulation and high air permeability.

Light-induced modulation of viscoelastic properties in azobenzene polymers.

Photo-induced isomerization of azobenzene molecules drives mass migrations in azopolymer samples. The resulting macroscopic directional photo-deformation of the material morphology has found many applications in literature, although the fundamental mechanisms behind this mass transfer are still under debate. Hence, it is of paramount importance to find quantitative observables that could drive the community toward a better understanding of this phenomenon. In this regard, azopolymer mechanical properties have been intensively studied, but the lack of a nanoscale technique capable of quantitative viscoelastic measurements has delayed the progress in the field. Here, we use bimodal atomic force microscopy (AFM) as a powerful technique for nanomechanical characterizations of azopolymers. With this multifrequency AFM approach, we map the azopolymer local elasticity and viscosity, with high resolution, after irradiation. We find that, while in the (previously) illuminated region, a general photo-softening is measured; locally, the Young modulus and the viscosity depend upon the inner structuring of the illuminating light spot. We then propose a possible interpretation based on a light-induced expansion plus a local alignment of the polymer chains (directional hole-burning effect), which explains the experimental observations. The possibility to access, in a reliable and quantitative way, both Young modulus and viscosity could trigger new theoretical-numerical investigations on the azopolymer mass migration dynamics since, as we show, both parameters can be considered measurable. Furthermore, our results provide a route for engineering the nanomechanical properties of azopolymers, which could find interesting applications in cell mechanobiology research.