Search Results (146,743)

This paper presents a novel approach to in situ memristive learning by training spiking neural networks (SNNs) entirely within the circuit using memristor emulators in SPICE. The circuit models neurons using Lapicque neurons and employs pulse-based spike encoding to simulate spike-timing-dependent plasticity (STDP), a key learning mechanism in SNNs. The Lapicque neuron model operates according to the Leaky Integrate-and-Fire (LIF) model, which is used in this study to model spiking behavior in memristor-based SNNs. More exactly, the first memristor emulator in PySpice, a Python library for circuit simulation, was developed and integrated into a memristive circuit capable of in situ learning, named the “In Situ Memristive Learning Method for Pattern Classification.” This novel technique enables time-based computation, where neurons accumulate incoming spikes and fire once a threshold is reached, mimicking biological neuron behavior. The proposed method was rigorously tested on three diverse datasets: XPUE, a custom non-dominating 3 × 3 image dataset; a 3 × 5 digit dataset ranging from 0 to 5; and a resized 10 × 10 version of the Modified National Institute of Standards and Technology (MNIST) dataset. The neuromorphic circuit achieved successful pattern learning across all three datasets, outperforming comparable results from other in situ training simulations on SPICE. The learning process harnesses the cumulative effect of memristors, enabling the network to learn a representative pattern for each label efficiently. This advancement opens new avenues for neuromorphic computing and paves the way for developing autonomous, adaptable pattern classification neuromorphic circuits. Full article

This paper investigates the strength and behaviour of high-strength self-compacting concrete-filled steel tubular (HSSC-CFST) stub columns under axial compression. HSSC-CFST columns are high-performance structural members with wide applications in engineering structures. Nevertheless, relevant studies have commonly focused on the mechanical performance of HSSC-CFST in indoor environments. A finite element (FE) model was developed to predict the axial load capacity of HSSC-CFST stub columns subjected to chloride corrosion. According to this, several crucial geometric and material parameters were designed to investigate the influences on strength, initial stiffness, and ductile performance. Moreover, the analysis on failure mechanisms was investigated by N-ε curves and stress development in the whole loading process. The impacts of key parameters on the reduction factor of axial load capacity were also identified. The numerical analysis results indicate that the axial strength of HSSC-CFST stub columns under chloride corrosion was significantly heightened by increasing the strength of core self-compacting concrete, while contrary results were found with the increase in the steel ratio and yield strength of the steel tube. Lastly, design recommendations for the axially loaded HSSC-CFST were presented by modifying the design codes in CECS104-99. The proposed model is shown to be able to estimate the axial load-bearing capacity of HSSC-CFST stub columns more accurately. Full article

In this work, we approach the forecast problem for a general non-homogeneous diffusion process over time with a different perspective from the classical one. We study the main characteristic functions as mean, mode, and $\alpha$-quantiles conditioned on a future time, not conditioned on the past (as is normally the case), and we observe the specific formula in some interesting particular cases, such as Gompertz, logistic, or Bertalanffy diffusion processes, among others. This study aims to enhance classical inference methods when we need to impute data based on available information, past or future. We develop a simulation and obtain a dataset that is closer to reality, where there is no regularity in the number or timing of observations, to extend the traditional inference method. For such data, we propose using characteristic functions conditioned on the past or the future, depending on the closest point at which we aim to perform the imputation. The proposed inference procedure greatly reduces imputation errors in the simulated dataset. Full article

Self-oscillation, a control approach inspired by biological systems, demonstrates an autonomous, continuous, and regular response to constant external environmental stimuli. Until now, most self-oscillation systems have relied on a static external environment that continuously supplies energy, while materials typically absorb ambient energy only intermittently. In this article, we propose an innovative self-oscillation of liquid crystal elastomer (LCE) fiber-slide system driven by a self-flickering light source, which can efficiently regulate the energy input in sync with the self-oscillating behavior under constant voltage. This system primarily consists of a photo-responsive LCE fiber, a slider that includes a conductive segment and an insulating segment, a light source, and a conductive track. Using the dynamic LCE model, we derive the governing equation for the motion of the LCE fiber-slider system. Numerical simulations show that the LCE fiber-slide system under constant voltage exhibits two distinct motion phases, namely the stationary phase and the self-oscillation phase. The self-oscillation occurs due to the photo-induced contraction of the LCE fiber when the light source is activated. We also investigate the critical conditions required to initiate self-oscillation, and examine key system parameters influencing its frequency and amplitude. Unlike the continuous energy release from the static environmental field in most self-oscillation systems, our LCE fiber-slide self-oscillation system is driven by a self-flickering light source, which dynamically adjusts the energy input under a constant voltage to synchronize with the self-oscillating behavior. Our design features advantages such as spontaneous periodic lighting, a simple structure, energy efficiency, and ease of operation. It shows significant promise for dynamic circuit systems, monitoring devices, and optical applications. Full article

The natural gas industry has developed rapidly in recent years, with gas storage playing an important role in regulating winter and summer gas consumption and ensuring energy security. The Ke7010 sand body is a typical edge water condensate gas reservoir with an oil ring, and the construction of gas storage has been started. In order to clarify the feasibility of synergistic storage building for gas injection and production, the fluid characteristics during the synergistic reservoir building process were investigated through several rounds of drive-by experiments. The results show that the oil-phase flow capacity is improved by increasing the number of oil–water interdrives, and the injection and recovery capacity is improved by increasing the number of oil–gas interdrives; the reservoir capacities of the high-permeability and low-permeability rock samples increase by about 4.84% and 7.26%, respectively, after multiple rounds of driving. Meanwhile, a numerical model of the study area was established to simulate the synergistic storage construction scheme of gas injection and extraction, and the reservoir capacity was increased by 7.02% at the end of the simulation period, which was in line with the experimental results. This study may provide a reference for gas storage construction in the study area. Full article

Food packaging plays an essential role in preserving food quality. However, heavy metals found in packaging materials—whether intentionally incorporated or not—can migrate into food. This study aims to evaluate the migration of specific heavy metals (Ba, Co, Cu, Zn, Al, Ni, Li, Fe, Pb, Cd, Cr, Sb) from plastic food packages (films and bags) obtained from various materials (PE, PP, PVC, composite materials) into food simulant B (3% acetic acid) using inductively coupled plasma mass spectrometry (ICP-MS). Migration tests was conducted according to EU regulations, using OM2 conditions (10 days at 40 °C). The obtained results were lower than the specific migration limits set by EU Regulation no. 10/2011 (Annex II). Both carcinogenic and non-carcinogenic risk assessments were carried out based on the specific migration data, estimating the exposure, average daily dose (ADD), hazard quotient (HQ), hazard index (HI), cancer risk (CR), and total cancer risk (TCR). The exposure values were found to be below the recommended tolerable daily intake (TDI) levels for each metal tested. Both HQ and HI values were under the limit value of 1. The average total cancer risk was 1.73 × 10⁻⁴, indicating that approximately 1.73 consumers out of 10,000 may develop a type of cancer due to chronic exposure to the tested metals. These results highlight the importance of continuous monitoring of chemical migrants from food contact materials. Full article

The field of view (FOV)-gated optical imaging system can relieve the contradiction between a wide FOV and the effective suppression of sky background radiation, making it particularly suitable for all-time star sensors. The detection capability of this novel optical imaging system during daytime differs significantly from that of traditional optical systems. This paper presents the principle of suppressing sky background radiation through FOV-gated imaging. Subsequently, the detection capabilities, including detectable limiting stellar magnitude and the probability of detecting at least three stars, are analyzed for applications on airborne platforms operating at altitudes of no less than 3km. Based on the analysis results, an FOV-gated imaging system operating in the shortwave infrared wavelength band was designed. Additionally, stray light analysis software, ASAP, was employed to simulate the illumination of stellar signals and sky background radiation on the detector. The evaluation of the detection capability of the designed FOV-gated optical system, based on simulation data, aligns with the theoretical analysis value. It demonstrates the system’s ability to detect multiple stars with a high probability during the daytime, thereby providing a theoretical foundation for the practical application of the FOV-gated optical imaging system on airborne platforms. Full article

The Jenolan Caves are the most spectacular limestone caves in Australia. Within this cave system, the Grand Arch, which is 24 m high, 55 m wide, and 127 m long, is the largest open cave in the country. A cave of this size could potentially accommodate small city streets, buildings, and other facilities. This paper examines a stability simulation of the Grand Arch, using numerical models to deduce foundational insights into rock openings under different geological and rock mass conditions. Following this, using numerical analysis, we investigate the creation of a man-made rock opening with the same span, height, and ground conditions of the Grand Arch but formed in two different arch shapes (i.e., with and without rock reinforcement as a stabilization measure). With all stability simulations conducted in this study, a clear explanation to describe the relationship and interaction between various parameters, such as rock mass structure and quality, rock mass strength, and in situ stress field, as well as different arch roofs shapes of the rock opening, is provided. Through its comparisons between natural rock cave and man-made rock openings, this study provides some findings and deep insight, as well as further questioning on creating a large size rock-reinforced cavern in different shapes to be opened in a range of rock conditions. Full article

Umami peptides have the ability to enhance food flavours and have potential health benefits. The objective of this study was to conduct a comprehensive investigation into the umami intensity, taste mechanism, and antioxidant activity of six umami peptides derived from wheat gluten hydrolysates (WGHs) and fermented WGHs. The e-tongue analysis demonstrated that the peptides exhibited a direct proportionality in terms of umami value and concentration, and were capable of enhancing the umami of commercially available condiments. The molecular dynamics simulations demonstrated that the peptides interacted with T1R1/T1R3 receptors via hydrogen bonds, hydrophobic interactions, ionic interactions, and water bridges, thereby producing umami. Furthermore, the DPPH, ABTS, hydroxyl radical-scavenging, and FRAP assays demonstrated that the six peptides exhibited antioxidant activity in vitro. Ultimately, the network pharmacology and molecular docking results indicated that AKT1, JUN, and CASP3 may serve as the core targets for the peptides in the treatment of oxidative diseases. In conclusion, this work offers novel insights into the use of bioactive umami peptides, emphasising their prospective applications in the food and health supplement industries. Full article

Background/Objectives: Digital impressions are increasingly used to manage Cleft lip and/or palate (CL/P), potentially offering advantages over traditional methods. This laboratory investigation sought to evaluate the impact of scanning tip sizes, different scanners, and scanning strategies on intraoral scanning in neonates with CL/P. Methods: Ten soft acrylic models were used to simulate the oral anatomy of neonates with CL/P, evaluating parameters such as the ability of different scanning tips to capture alveolar cleft depth, scanning time, number of scan stops, and scan quality. The study utilised various scanning tips, including the Carestream normal tip, Carestream side tip, and Trios 4 scanner tip to assess the alveolar cleft depth measurements. The Trios 4, Carestream, and iTero scanners were evaluated for the time taken, number of scan stops during cleft-unobstructed scanning and cleft-obstructed scanning. The quality of all scanned images was analysed. Results: The findings showed comparable accuracy in capturing alveolar cleft depth with the three-scanning tip (p > 0.05). Scanning time and the number of scan stops did not significantly differ across the three scanners and various scanning strategies employed (p > 0.05). However, scanning with the cleft obstructed required less time and resulted in fewer scan stops compared to cleft -unobstructed scanning. Despite these results, all scanners failed to record the deepest part of the alveolar cleft, highlighting a limitation in current scanning technology for neonates with CL/P. Conclusions: The study recommends enhancing intraoral scanning in this population by adjusting tip size, improving clinician training, optimizing protocols, and conducting further research to improve techniques. Full article

The research focused on enhancing the seismic performance of steel moment frames using cable braces and a central friction damper. By optimizing the design and pretensioning force of the cable braces, this study aimed to improve the energy absorption and overall behavior of the frames under cyclic earthquake loads. A quasi-cyclic loading test was developed through FE simulations using ABAQUS software, version 2023. To verify the modeling, an experimental test was compared with the numerical modeling, and the numerical results confirmed the accuracy of the experimental data. Results made by modeling in ABAQUS software (version 2023) include the impact of pretensioning force on stiffness and energy absorption, the relationship between pretensioning force and force required to move the target, the increase in absorbed energy with pretension force up to 25%, and the superior seismic performance of frames with rotational friction dampers. This study also highlighted the benefits of using cable braces with a friction damper regarding the symmetry of hysteresis diagrams, cyclic performance, and energy absorption capacity. The amount of pretensioning of the cables affects the energy dissipation capacity. As the pretensioning of the cables increases, the energy dissipation capacity initially increases. However, further increases in pretensioning lead to decreased energy dissipation capacity beyond a certain point. When the percentage of cable brace pretension increases from 2% to 25%, the energy dissipation capacity is enhanced by 2%, and when in the 25–30% range, it stabilizes at around 35%. Energy dissipation capacity decreases for pretensions of more than 30%. Full article

Deep reinforcement learning models have the advantage of being able to control nonlinear systems in an end-to-end manner. However, reinforcement learning controllers trained in simulation environments often perform poorly with real robots and are unable to cope with situations where the dynamics of the controlled object change. In this paper, we propose a DRL control algorithm that combines progressive networks and context as a depth tracking controller for AUVs. Firstly, an embedding network that maps interaction history sequence data onto latent variables is connected to the input of the policy network, and the context generated by the network gives the DRL agent the ability to adapt to the environment online. Then, the model can be rapidly adapted to a new dynamic environment, which was represented by the presence of generalized force disturbances and changes in the mass of the AUV, through a two-stage training mechanism based on progressive neural networks. The results showed that the proposed algorithm was able to improve the robustness of the controller to environmental disturbances and achieve fast adaptation when there were differences in the dynamics. Full article

Depopulation, aging, and regional decline are becoming increasingly serious issues in Japan’s hilly and mountainous areas. Focusing on mitigating environmental damage and envisioning a sustainable future for these regions, this study examines the potential for reducing CO₂ emissions in the residential and transportation sectors by 2050. Bottom-up simulations were used to estimate CO₂ emissions. Subsequently, six decarbonization scenarios were formulated, considering various measures from the perspectives of population distribution and technological progress. Based on these scenarios, this study analyzes changes in future population, energy consumption, and CO₂ emissions by 2050. The results of this study show the following. (1) Depopulation and aging problems in these regions are expected to become more severe in the future. It is necessary to take action to promote sustainable regional development. (2) Pursuing decarbonization has a positive impact on enhancing regional sustainability; however, maintaining the intensity of measures at the current level could lead to a reduction of only 40% in CO₂ emissions per capita by 2050 compared with 2020. (3) Scenarios that strengthen decarbonization measures could achieve a reduction of over 95% by 2050, indicating that carbon neutrality is attainable. However, this will require implementing measures at a higher intensity, especially in the transportation sector. Full article

Common oat (Avena sativa L.) is one of the important minor grain crops in China, and drought stress severely affects its yield and quality. To investigate the drought resistance characteristics of oat seedlings, this study used Baiyan 2, an oat cultivar at the three-leaf stage, as the experimental material. Drought stress was simulated using polyethylene glycol (PEG) to treat the seedlings. The photosynthetic parameters and physicochemical indices of the treatment groups at 6 h and 12 h were measured and compared with the control group at 0 h. The results showed that drought stress did not significantly change chlorophyll content, but it significantly reduced net photosynthetic rate and other photosynthetic parameters while significantly increasing proline content. Transcriptome analysis was conducted using seedlings from both the control and treatment groups, comparing the two treatment groups with the control group using Tbtool software (v2.136). This analysis identified 344 differentially expressed genes. Enrichment analysis of these differentially expressed genes revealed significant enrichment in physiological pathways such as photosynthesis and ion transport. Ten differentially expressed genes related to the physiological process of photosynthetic carbon assimilation were identified, all of which were downregulated. Additionally, seven differentially expressed genes were related to ion transport. Through gene co-expression analysis combined with promoter region structure analysis, 11 transcription factors (from MYB, AP2/ERF, C2C2-dof) were found to regulate the expression of 10 genes related to photosynthetic carbon assimilation. Additionally, five transcription factors regulate the expression of two malate transporter protein-related genes (from LOB, zf-HD, C2C2-Dof, etc.), five transcription factors regulate the expression of two metal ion transporter protein-related genes (from MYB, zf-HD, C2C2-Dof), five transcription factors regulate the expression of two chloride channel protein-related genes (from MYB, bZIP, AP2/ERF), and two transcription factors regulate the expression of one Annexin-related gene (from NAC, MYB). This study provides a theoretical foundation for further research on the molecular regulation of guard cells and offers a molecular basis for enhancing drought resistance in oats. Full article

This study examines the three-axis vibration isolation capabilities of a full-scale magnetorheological (MR) seat suspension system utilizing experimental methods to assess performance under both single-axis and simultaneous three-axis input conditions. To achieve this, a semi-active MR seat damper was designed and manufactured to address excitations in all three axes. The damper effectiveness was tested experimentally for axial and lateral motions, focusing on dynamic stiffness and loss factor using an MTS machine. Prior to creating the full-scale MR seat suspension, a scaled-down version at one-third size was developed to verify the damper’s ability to effectively reduce vibrations in response to practical excitation levels. Additionally, a narrow-band frequency-shaped semi-active control (NFSSC) algorithm was developed to optimize vibration suppression. Ultimately, a full-scale MR seat suspension was assembled and tested with a 50th percentile male dummy, and comprehensive three-axis vibration isolation tests were conducted on a hydraulic multi-axis simulation table (MAST) for both individual inputs over a frequency range up to 200 Hz and for simultaneous multi-directional inputs. The experimental results demonstrated the effectiveness of the full-scale MR seat suspension in reducing seat vibrations. Full article