Dissipation Research Articles

Non-linear saturation and energy transport in global simulations of magneto-thermal turbulence in the stratified intracluster medium

The magneto-thermal instability (MTI) is one of many possible drivers of stratified turbulence in the intracluster medium (ICM) outskirts of galaxy clusters, where the background temperature gradient is most likely aligned with the gravity. This instability occurs because of the fast anisotropic conduction of heat along magnetic field lines. However, the extent to which it impacts the ICM dynamics, energetics, and overall equilibrium is still a matter of debate. This work aims to understand MTI turbulence in an astrophysically stratified ICM atmosphere, its underlying saturation mechanism, and its ability to carry energy and to provide non-thermal pressure support. We performed a series of 2D and 3D numerical simulations of the MTI in global spherical models of a stratified ICM thanks to the finite-volume Godunov-type code IDEFIX and using Braginskii magnetohydrodynamics. We used well-controlled volume-averaged, shell-averaged, and spectral diagnostics to study the saturation mechanism of the MTI and its radial transport energy budget. The MTI is found to saturate through a dominant balance between injection and dissipation of available potential energy, which amounts to marginalising the Braginskii heat flux but not the background temperature gradient itself. Accordingly, the strength and injection length of MTI-driven turbulence exhibit clear dependencies on the thermal diffusivity. With realistic Spitzer conductivity, the MTI drives cluster-size motions with Mach numbers up to $ M 0.3$, even in the presence of strong stable entropy stratification. We show that such mildly compressible flows can provide about $ 15<!PCT!>$ of the non-thermal pressure support in the outermost ICM regions close to the cluster accretion shock and that the convective transport itself is much less efficient (a few percent only) than conduction at radially transporting energy. Finally, we show that the MTI saturation can be described by a diffusive mixing-length theory, shedding light on the diffusive buoyant nature, rather than the adiabatic convective nature, of the instability. The MTI seems relevant to both the dynamics and energetics of the ICM through radially biased magnetic fields that enhance the background Braginskii heat flux. Further work including externally forced turbulence, for instance, mimicking accretion-induced turbulence, is needed to assess its overall relative importance in comparison to other drivers of ICM turbulence.

Study on brittleness characteristics of deep shale: A case study of Lu211 well in the Luzhou block.

Ensuring the sustainability of energy is pivotal for achieving a harmonious balance between environmental conservation and economic growth. The mechanical behavior of deep shale reservoir rocks is intricate, presenting challenges in ascertaining their brittleness characteristics. To address this, the study employed a suite of evaluation techniques, encompassing analyses of stress-strain curve attributes, energy dissipation patterns, and mineral composition profiles. The overarching goal was to delineate the variations in deep shale brittleness as a function of depth. The findings indicate a general trend of decreasing shale brittleness with increasing depth. However, the brittleness indices derived from the three distinct evaluation methods varied, with the mineral composition approach yielding the most scattered results. This disparity underscores the heterogeneity of deep shale, likely due to its varied diagenetic history compared to shallower formations. In response to these observations, the study leveraged the principle of weighted averaging to devise a composite brittleness evaluation method. This innovative approach not only integrates the effects of multiple influencing factors but also accounts for the differential impact and weight of each method on the overall brittleness assessment. By doing so, it offers a more nuanced and holistic understanding of shale brittleness. The paper's exploration of deep shale's brittleness characteristics contributes valuable insights for the exploration and development of deep shale reservoirs, enhancing the strategic and operational frameworks within the energy sector. This comprehensive evaluation method serves as a foundation for more informed decision-making, ensuring that energy extraction is conducted in a manner that is both economically viable and environmentally responsible.

Application Research of a High Turbulence Numerical Simulation Technique in a USBR Type III Stilling Basin

In view of the energy dissipation design of the USBR Type III stilling basin, which is characterized by intense turbulent flow and complex flow patterns, a reliable mathematical model and calculation method is used to track and record the changes of flow parameters during fluid movement. The results of flow movement can be obtained, and the changes to the whole and local parameters of the flow field can be accurately simulated. Using the case of the discharge sluice stilling basin of the flood storage ecological treatment project of Jinchang Industrial Base in Gansu Province, this paper simulates the flow pattern through numerical calculation, thereby saving labor and material costs. The design cycle is also greatly shortened compared with the physical model test, and the technique has good repeatability, controllability, convenient optimization design, and provides technical support and quality assurance for complex energy dissipation problems.

Macroscopic and Mesoscopic Damage Characteristics and Energy Evolution Laws of Rock Mass With Double Arcuate Fractures Under Uniaxial Compression

ABSTRACTIn order to reveal the influence of double arc‐shaped fissure dip angles on the macro‐micro failure and energy evolution laws of rock masses, a numerical model of red sandstone was firstly established using the PFC2D. Moreover, mesoscopic parameters of the numerical model were calibrated based on the uniaxial compression tests on intact and single straight fissure red sandstone specimens. Then, particle flow simulation tests of red sandstone with different arc‐shaped fissure dip angles were carried out. The results show that the peak strength and elastic modulus both increase with the increase of arc‐shaped fissure dip angle α, exhibiting an oblique shear‐tensile failure pattern. Six types of cracks evolved during the instability and rupture of the rock mass with double arc‐shaped fissures. The macroscopic fissures in the rock mass ultimately penetrate along the extension direction of the arc‐shaped fissures. As the arc‐shaped fissure dip angle α increases, the crack evolution is positively correlated with the acoustic emission (AE) of the specimen. When approaching instability failure, the AE ringing count rapidly increases. There is a critical angle limit inflection point for the total energy absorbed by the rock between 60° and 75°, with a total energy increase of about 54%. During instability failure, it is dominated by dissipative energy, with elastic energy as a supplement. This article derived a damage constitutive model of red sandstone with different arc‐shaped fissure dip angles, revealing the damage laws of red sandstone under different arc‐shaped fissure dip angles.

Seismic Performance Research on a Graded-Yielding Metal Brace with Self-Centering Functions

With the aim of achieving a graded-protection braced frame structure and minimizing the excessive residual deformation of traditional metal dampers under intense seismic action, a graded-yield-type metal self-centering brace (SC-GYMB) is proposed. The brace is composed of X-shaped and U-shaped steel plates with different yield point displacements, which jointly dissipate energy. Additionally, it employs a composite disc spring as a self-centering element to provide restoring force for the brace. The brace’s basic structure and working mechanism are described, and the theoretical model for its restoring force is derived. The ABAQUS finite element software (ABAQUS 2021) is utilized to investigate the hysteretic performance of the SC-GYMB under low-cycle reciprocating load, while thoroughly discussing the influence of various model parameters on its key mechanical behavior. The results demonstrate a strong agreement between the theoretical restoring force model and the numerical simulation results. The hysteretic curves of the braces exhibit a distinct “flag” characteristic, indicating excellent energy dissipation capacity and self-centering performance. Moreover, these curves display a hierarchical yield behavior that satisfies the seismic performance requirements for different intensity earthquakes. The deformation mechanism of X-shaped steel sheets transitions from bending deformation during the initial loading stage to tensile deformation in the subsequent loading stage. Increasing the initial pre-compression force of the combined disc spring enhances the restoration performance of the brace. Augmenting the thickness of X-shaped or U-shaped steel sheets modifies the displacement and load at both the first and second yield points, thereby enhancing energy dissipation capacity and bearing capacity of the brace; however, it also leads to increased residual deformation.

Application of precast reinforced concrete fuse units as energy dissipation units in various self-centering precast bridge pier systems

This study proposes the implementation of scaled modular reinforced concrete (RC) units as replaceable energy dissipation (ED) elements in various RC self-centering (SC) precast bridge pier (PBP) systems. Regarding the resistance mechanism of RC ED units, two types can be integrated with the main SC system: modular RC units that dissipate energy through the well-known plastic hinge mechanism, and hybrid modular precast SC units that dissipate energy through the yielding of mild steel reinforcement. Using commercial finite element (FE) software, three-dimensional (3D) FE models for different PBP systems (single-column, double-column, and wall PBP systems) were developed and examined under lateral cyclic loading. Various potentially influential design parameters were carefully studied. The studied cases successfully demonstrated that the proposed system introduces a novel, cost-effective damage-control system, which provides customizable ED capabilities, offers additional designable lateral resistance, and ensures rapid repair without compromising the functionality of the main SC structural system. Furthermore, in accordance with the design codes/guidelines for concrete structures exposed to earthquakes, the components defined as ED units can achieve the predefined seismic response without compromising the seismic performance or SC capacity of the main system.

Analysis of Tidal Cycle Wave Breaking Distribution Characteristics on a Low-Tide Terrace Beach Using Video Imagery Segmentation

Wave breaking is a fundamental process in ocean energy dissipation and plays a crucial role in the exchange between ocean and nearshore sediments. Foam, the primary visible feature of wave breaking areas, serves as a direct indicator of wave breaking processes. Monitoring the distribution of foam via remote sensing can reveal the spatiotemporal patterns of nearshore wave breaking. Existing studies on wave breaking processes primarily focus on individual wave events or short timescales, limiting their effectiveness for nearshore regions where hydrodynamic processes are often represented at tidal cycles. In this study, video imagery from a typical low-tide terrace (LTT) beach was segmented into four categories, including the wave breaking foam, using the DeepLabv3+ architecture, a convolutional neural networks (CNNs)-based model suitable for semantic segmentation in complex visual scenes. After training and testing on a manually labelled dataset, which was divided into training, validation, and testing sets based on different time periods, the overall classification accuracy of the model was 96.4%, with an accuracy of 96.2% for detecting wave breaking foam. Subsequently, a heatmap of the wave breaking foam distribution over a tidal cycle on the LTT beach was generated. During the tidal cycle, the foam distribution density exhibited both alongshore variability, and a pronounced bimodal structure in the cross-shore direction. Analysis of morphodynamical data collected in the field indicated that the bimodal structure is primarily driven by tidal variations. The wave breaking process is a key factor in shaping the profile morphology of LTT beaches. High-frequency video monitoring further showed the wave breaking patterns vary significantly with tidal levels, leading to diverse geomorphological features at various cross-shore locations.

Synergistic Multimodal Energy Dissipation Enhances Certified Efficiency of Flexible Organic Photovoltaics beyond 19.

All-polymer organic solar cells (OSCs) have shown unparalleled application potential in the field of flexible wearable electronics in recent years due to the excellent mechanical and photovoltaic properties. However, the small molecule acceptors after polymerization in still retain some mechanical and aggregation properties of the small molecule, falling short of the ductility requirements for flexible devices. Here, based on the multimodal energy dissipation theory, the mechanical and photovoltaic properties of flexible devices are co-enhanced by adding the thermoplastic elastomer material (polyurethane, PU) to the PM6:PBQx-TF:PY-IT-based active layer films. The construction of multi-fiber network structure and the decrease of films' residual stresses contribute to the enhancement of carrier transport properties and the decrease of defect state density. Eventually, the PCE (power conversion efficiency) of 19.40% is achieved on the flexible devices with an effective area of 0.102 cm2, and the third-party certified PCE reaches 19.07%, which is the highest PCE for flexible OSCs currently available. To further validate the potential of this strategy for large-area module applications, the 25-cm2-based flexible and super-flexible modules are prepared with the PCEs of 15.48% and 14.61%, respectively, and demonstration applications are implemented.

Photosynthetic Efficiency of Plants as an Indicator of Tolerance to Petroleum-Contaminated Soils

Significant efforts have been made to develop environmentally friendly remediation methods to restore petroleum-damaged ecosystems. One such approach is cultivating plant species that exhibit high resistance to contamination. This study aimed to assess the impact of petroleum-derived soil pollutants on the photosynthetic performance of selected plant species used in green infrastructure development. A pot experiment was conducted using both contaminated and uncontaminated soils to grow six plant species under controlled conditions. Biometric parameters and chlorophyll a fluorescence measurements were taken, followed by statistical analyses to compare plant responses under stress and control conditions. This study is the first to simultaneously analyze PF, DF, and MR820 signals in plant species exposed to petroleum contamination stress. The results demonstrated that petroleum exposure reduced the activity of both PSII and PSI, likely due to increased nonradiative energy dissipation in PSII antenna chlorophylls, decreased antenna size, and/or damage to the photosynthetic apparatus. Additionally, petroleum contamination affected the electron transport chain efficiency, limiting electron flow between PSII and PSI. The most resistant species to petroleum-induced stress were Lolium perenne, Poa pratensis, and Trifolium repens.

Optimized leakage control in CMOS NAND gates: The In-Triggering technique

Abstract Leakage power, now the largest contributor to integrated circuit power consumption, is rising quickly, according to the International Technology Roadmap for Semiconductors (ITRS). As CMOS (complementary metal-oxide semiconductor) technology continues to shrink to deep submicron levels, gate leakage and subthreshold have become important components that contribute to total power dissipation. To address this problem, many methods have been put forth, especially at the circuit level. In 45 nm CMOS, variability and short-channel effects limit noise margins and compromise gate delays, thereby compromising the timing closure and robustness of ultra-low voltage circuits. The resulting supply voltage guardband may reduce energy efficiency in order to achieve a reasonable production yield. Furthermore, the high leakage currents of these technologies decrease energy efficiency when idle intervals are prolonged. In this study, two designs of a novel two-input NAND gate at 45 nm CMOS technology are constructed using eight transistors (8-T). A novel circuit technique named "In-Triggering (INDEP with Bi-Triggering)" is presented in this study with the goal of lowering subthreshold leakage in digital circuits. This method is thoroughly contrasted with other leakage reduction strategies now in use, such as Base, Sleepy LECTOR, LECTOR, INDEP, and Bi-Triggering procedures. Evaluation is done using key performance measures such power-delay product (PDP), latency, subthreshold leakage power, and total power consumption. 45-nm Predictive Technology Models (PTM) with a nominal supply voltage of 1V are used in the investigation. According to our findings, the suggested In-Triggering technique outperforms the conventional NAND gate in terms of speed by 12% and significantly reduces leakage power by up to 56%. Furthermore, compared to the Base, Trig01, and INDEP NAND gates, the method offers mean power savings of 58.8%, 36.1%, and 30.7%, respectively. At supply voltages of 1V, a comprehensive comparison and verification are then conducted utilizing the several proposed and existing methodologies. The effectiveness of the In-Triggering technique in reducing leakage power in CMOS circuits is confirmed by comparing these results to the most well-known design strategies for both active operation and sleep modes.

Mechanically Robust Triboelectric Aerogels Enabled by Dense Bridging of MXene.

Aerogels are widely applied for construction, aerospace, military, and energy owing to their lightweight, high specific surface area, and high porosity. The high porosity of aerogels often leads to a lack of mechanical strength, which limits their applications. Here, this study reports a mechanically robust MXene/cellulose nanocrystal composite aerogel enabled by inducing dense bridging through salting-out. First, MXene sheets are bridged with cellulose molecular chains via hydrogen bonds, and further dense bridging is constructed by promoting hydrogen bond formation through salting-out. By enhancing hydrogen bonding, the interlayer spacing of MXene sheets is reduced and their orientation is improved, effectively increasing the energy dissipation capacity of the porous structure. The aerogel exhibits a Young's modulus of 72.4 MPa, a specific modulus of 342.0 kN m/kg. An aerogel is used as a triboelectric material to construct a highly robust triboelectric nanogenerator. This study provides an effective strategy for the preparation of the mechanically robust aerogels.

Fracture Behavior and Biocompatibility of Cellulose Nanofiber-Reinforced Poly(vinyl alcohol) Composite Hydrogels Cross-Linked with Borax.

We investigated the fracture behavior of cellulose nanofiber (CNF)-reinforced poly(vinyl alcohol) (PVA) hydrogels cross-linked with borax and the effect of freeze-thaw (FT) cycles on it. The CNF/PVA/Borax hydrogel not subjected to FT achieved a fracture energy of 5.8 kJ m-2 and a dissipative length of 2.3 mm, comparable to those of tough hydrogels. Lacking either CNF or borax remarkably decreased the fracture energy and the dissipative length; CNF contributed to a physical blocking of the crack growth, whereas the complexations between CNF and borate yielded nonlocalization of energy dissipation. Repeated FT cycles markedly improved the mechanical performance of unnotched samples, but they decreased the fracture energy due to the lowering of the dissipative length. Besides, CNF/PVA/Borax hydrogels were suitable for cell scaffold materials. The culture of umbilical cord mesenchymal stem cells (UC-MSCs) revealed a positive correlation between culture duration and the number of UC- MSCs adherent to the material.

A Wide Range Duty‐Cycle PWM Generator Using Oxide‐TFTs on a Flexible Substrate

ABSTRACTThis work presents an experimental characterization of a novel clocked regenerative comparator with oxide TFT (a‐IGZO) technology on a flexible substrate. The circuit functionality is demonstrated as a wide range duty‐cycle PWM signal generator with a triangular input signal. The regenerative latch in the comparator is implemented with diode‐load–based inverters. The proposed circuit has shown a linear variation in the duty‐cycle from 12% to 84%, when the reference voltage () is varied from 0.5 to 3.3 V, respectively, in the clocked comparator. Further, a reliable operation is observed up to an input signal frequency of 2 kHz at a supply voltage of 4 V, with a power dissipation of 20 W. This circuit would find potential applications in wearable bio‐medical and neuromorphic computational systems.

Research on the Impact of Coastal Land Reclamation on Geomorphic Complexity and Tidal Energy Dissipation—A Case Study of Zhoushan Islands, Hangzhou Bay

ABSTRACTCoastal mudflats are vital land resources. In recent years, coastal reclamation has emerged as a vital strategy for alleviating coastal land supply shortages and for developing marine resources in coastal areas. However, large‐scale coastal reclamation changes the natural landscape properties of sea areas, triggering alterations in the surrounding hydrodynamic and ecological environments. Despite the significant impact of coastal geomorphic features on tidal energy loss and disaster prevention, few studies have explored the intrinsic connection between the complexity of coastal landscapes and the rate of tidal reduction. This relationship is crucial for predicting potential tidal energy loss responses to large‐scale changes in geomorphologic features caused by accelerating coastal land reclamation. This study focuses on Hangzhou Bay as the research area and develops a model that combines the correlation between the rate of tidal reduction and the complexity of coastal landscapes. The model is constructed using fractal geometry theory and quantitative methods, while also incorporating principles from ocean dynamics theory. The model is applied to assess the impacts of reclaimed land on the geomorphic complexity and tidal energy dissipation in the Zhoushan Islands. Results indicate a high correlation between differential tide reduction rates and coastal geomorphic complexity. Application of this model reveals that traditional reclamation planning and design substantially alter coastal morphology. Consequently, the significant reduction in the fractal dimension (D) and shape index (S) leads to a tidal reduction rate decrease of over 88%, posing substantial threats to coastal and estuarine bay disaster prevention and ecosystem services. The study proposes effective control indicators and scientific reclamation planning measures, providing a theoretical basis and novel methods for the rational utilization and sustainable development of coastal mudflat resources.

Modal Frequency and Damping Identification of the FAST Cabin-Cable System

The Five-Hundred-Meter Aperture Spherical Radio Telescope (FAST) faces challenges in establishing high-precision rigid connections between the receiver and the reflective surface due to its vast spatial span. Innovatively, FAST suspends the feed cabin in mid-air using six supporting cables. The precise positioning of the feed focal point is achieved through the coordinated control of cable extension and retraction, along with the A-B axis and the Stewart platform within the cabin. The cables and the feed cabin form a large parallel mechanism. Since the cables are flexible, and the feed cabin remains at a high altitude during observations, it is inevitably subject to internal and external disturbances. To quickly dissipate these disturbances, the system requires a certain level of damping, which directly affects the pointing and tracking accuracy of FAST. During the 2022–2023 operational period, there were multiple instances where the pulleys of the curtain mechanism on the supporting cables became stuck and were carried to the top of the towers by the cables. This also led to the phenomenon where the pulleys, after being stuck, would rapidly slide down the cables due to accumulation. At such moments, the cabin-cable system would experience instantaneous excitation, causing vibrations. This study uses the intrinsic time-scale decomposition (ITD) method to analyze the inertial navigation data installed in the cabin during these events, identifying modal frequencies and damping ratios. The analysis results show that the lowest primary vibration frequency of the FAST cabin-cable suspension system ranges from approximately 0.12 to 0.2 Hz, with a damping ratio of no less than 0.004. These data indicate that the current structure of FAST has a strong energy dissipation capability, providing important reference points for improving the control accuracy of FAST and for the upgrade of the feed support system.

Evaluation of Dynamic Properties of Sand Mixed with Expanded Glass Granules by Energy Concept Under Cyclic Torsional Loadings

In recent years, lightweight materials have gained attention for their numerous benefits, including cost reduction, insulation, and bearing capacity. Expanded glass granules (EGG) stand out among these materials, showing significant potential in geotechnical engineering applications. This study examines the potential use and feasibility of a SAND-EGG mixture in geotechnical applications through cyclic torsional shear test for measuring shear strength, modulus reduction, and energy dissipation. This is conducted on the unmixed dry specimens (Reference Sand, EGG) and the mixed dry specimens by mass (1, 2%) and volume (5, 10, 15%) under 100 kPa effective pressure. The test also conducted along 0.02%–0.5% shear strain amplitudes for both samples group. An energy-based approach is used to analyze mixed material's capacity for energy dissipation, a crucial factor in determining seismic resistance during cyclic loading. The impact of employing EGG on modulus reduction behavior was also explored concerning energy dissipation. Considering the results, it is show that the use of EGG increases the resilience with high friction capacity and by taking up a significant portion of the available void ratio and provides lightness in geotechnical applications in examined shear strain amplitude range (0.02%–0.5%).

Quasi-Static Finite Element Analysis and Damage Quantitative Evaluation of Special-Shaped Concrete-Filled Steel Tubular Column Composite Frame Structure

ABSTRACT Based on the elaborate 3D solid finite element (FE) model established by ABAQUS software, a pseudo-static analysis was conducted on a special-shaped concrete-filled steel tubular column composite frame structure. The FE model considers the confinement effect of both the steel tubes and the tensile bars exerting on the core concrete. The results of the numerical analysis concerning failure modes, load-displacement hysteretic curves, load-displacement skeleton curves and stiffness degradation-displacement curves demonstrate a strong correlation with the existing quasi-static test data. Furthermore, an in-depth analysis was conducted on the impact of the axial compression ratio of column on the plastic energy dissipation distribution mechanism. With an axial compression ratio of the column ranging from 0.1 to 0.55, the composite frame structure primarily relies on the energy dissipation of beams, while the columns serve as supplementary support, thereby exemplifying the principle of “strong column-weak beam.” As the axial compression ratio rises to the range of 0.6–0.8, the composite frame structure transitions a “strong beam-weak column” structural system. Combined with the longitudinal compressive strain of the steel tube at the bottom of the column, a quantitative evaluation method for seismic damage is proposed, grounded in indexes of “stiffness damage” and “energy damage.” Then, the threshold values of energy damage and stiffness damage are determined across four distinct levels: “elastic stage in small earthquake,” “elasto-plastic stage in medium earthquake,” “plastic stage in heavy earthquake” and “failure stage.” The proposed method effectively evaluate the damage severity of special-shaped CFT column composite frame structure subjected to seismic events.

Historical perspective and opportunity for computing in memory using floating-gate and resistive non-volatile computing including neuromorphic computing

Abstract The effort addresses the research activity around the usage of Non-Volatile Memories (NVM) for storage of “weights” in neural networks and the resulting computation through these memory crossbars. In particular, we focus on the CMOS implementations of, and comparisons between, Memristor / RRAM devices, and Floating-Gate (FG) Devices. A historical perspective for illustrating FG and Memristor /RRAM devices enables comparison of nonvolatile storage (addressing issues related to resolution, lifetime, endurance etc.), feedforward computation (different variants of vector matrix multiplication, tradeoffs between power dissipation and signal to noise ratio etc.), programming (addressing issues of selectivity, peripheral circuits, charge trapping etc.), and learning algorithms (continuous time LMS or batch update), in these systems. We believe this historical perspective is necessary and timely given the increasing interest in using Computation in Memory with NVM for a wide variety of memory bound applications.

Influence of damage degree of recycled coarse aggregate concrete-filled steel tube columns strengthened with envelope steel jacket under seismic load

ABSTRACT In order to discuss the influence of damage degree of recycled coarse aggregate concrete-filled steel tube columns strengthened with envelope steel jacket (ESJ) under seismic load, eight columns were designed and manufactured to simulate seismic loading, with the design of ESJ strengthening after pre-damage and destruct tests under seismic load. This experiment was conducive to accurately evaluating the influence mechanism and synergistic effect of seismic damage degree and recycled coarse aggregate on the hysteresis curve, skeleton curve, ductility performance, energy dissipation performance, and bearing capacity performance of each specimens, and a suitable seismic damage model was proposed. The ductility coefficient is from 3.36 and 4.64, satisfying the requirements of seismic design. The research results indicate that the degree of seismic damage and recycled coarse aggregate are unfavorable to improve the seismic performance of recycled coarse aggregate concrete-filled steel tube columns strengthened with ESJ under seismic load; Taking the ductility coefficient of specimen SEJS-0 as the basic data, specimens SEJS-1 to SEJS-3 and FC-0 to FC-3 increased by 22.02%, 20.24%, 8.33%, 18.15%, 38.10%, 35.71%, and 23.51%, respectively. Under moderate and severe damage, the ductility performance of enveloped steel jacket-strengthened seismic-damaged specimens decreased by 15.47% and 15.18%, respectively, and the reduction amplitude of both was similar. As the degree of seismic damage increases, the value of the ultimate bearing capacity first decreases and then increases. The method of using recycled coarse aggregate to replace half of natural coarse aggregate has certain feasibility in the field of concrete-filled steel tube columns. Recycled coarse aggregate has a significant impact on the bearing capacity of each stage, while the degree of seismic damage only has a greater impact on the ultimate stage. The established seismic damage model for recycled coarse aggregate concrete-filled steel tube columns strengthened with ESJ under seismic load is feasible and can be used for quantitative evaluation of the seismic capacity of such components.

High-Precision Digital-to-Time Converter with High Dynamic Range for 28 nm 7-Series Xilinx FPGA and SoC Devices

Over the last ten years, the need for high-resolution time-domain digital signal production has grown exponentially. More than ever, applications call for a digital-to-time converter (DTC) that is extremely accurate and precise. Skew compensation and camera shutter operation represent just a few examples of such applications. The advantages of adopting a flexible and rapid time-to-market strategy focused on fast prototyping using programmable logic devices—such as field-programmable gate arrays (FPGAs) and system-on-chip (SoC)—have become increasingly evident. These benefits outweigh those of performance-focused yet expensive application-specific integrated circuits (ASICs). Despite the availability of various architectures, the high non-recurring engineering (NRE) costs make them unsuitable for low-volume production, especially in research or prototyping environments. To address this trend, we introduce an innovative DTC IP-Core with a resolution, also known as least significant bit (LSB), of 52 ps, compatible with all Xilinx 7-Series FPGAs and SoCs. Measurements have been performed on a low-end Artix-7 XC7A100TFTG256-2, guaranteeing a jitter lower than 50 ps r.m.s. and offering a high dynamic range up to 56 ms. With resource utilization below 1% and a dynamic power dissipation of 285 mW for our target FPGA, the design maintains excellent differential and integral nonlinearity errors (DNL/INL) of 1.19 LSB and 1.56 LSB, respectively.