Peak Deviation Research Articles

Building Detection and Outlining in Multi-Modal Remote Sensor Data: A Stratified Approach

Exploitation of aerial sensor data for vectorized representation of urban structures is of great importance for urban modeling. Even if elevation data is available, extracting complex and irregular building shapes would become challenging. In this paper, we present a stratified approach for the extraction of building outlines consisting of two steps: Classification and vectorization. For classification, we use training data transfer to evaluate a dataset with no or little labeled data. Since the available reference data is also flawed, we use a self-developed interactive tool to adjust and improve the building shape before contrasting it with the classification results. Initial building polygons are slightly generalized and refined considering building shape characteristics. Hereby, Least-Squares adjustment is implemented to solve the best-fit problem of building edges with the input data by applying the Gauss-Helmert and Gauss-Markov Models. On the raster level, the resulting polygons achieved an accuracy of over 99% in the Potsdam dataset and almost 98% in the Munich dataset while on the vector level, the median building-wise deviations lie in sub-meter range. Although there were few mis-detections and, sometimes, considerable peak deviations for the Hausdorff distance, the compelling qualitative results attest to the robustness and validity of the proposed procedure.

Trajectory priming through obstacle avoidance in motor imagery – does motor imagery comprise the spatial characteristics of movement?

Motor imagery and execution often indicate a similar trend in the temporal characteristics of movements. This finding supports the notion of functional equivalence, whereby imagery and execution use a common neural representation. However, there is comparatively limited evidence related to the spatial characteristics of movements; no doubt owing to the absence of an actual spatial trajectory during imagery. Therefore, we adapted the trajectory priming paradigm involving an obstacle, where the trajectory adopted in a trial (n) is directly contaminated by a previous trial (n-1). If imagery accurately represents the spatial characteristics, then we would predict a similar priming effect as execution. Participants completed a series of trial blocks under different imagery/execution protocols, where the test trial (n) comprised execution alone, while the previous trial (n-1) involved imagery or execution. Each block comprised pairs of trials with alternate or consistent presentations of a virtual obstacle (O) or no obstacle (N): N-N, N-O, O-N, O-O. For trial n-1 (imagery/execution), there was a more prolonged reaction and movement time for imagery compared execution. Most importantly for trial n (execution), there was an increase in early angular and peak deviation following an obstacle compared to no obstacle in trial n-1, but only when it was execution and not imagery. These findings suggest imagery holds a limited representation of the spatial characteristics, while functional equivalence may be limited to the temporal characteristics.

Mechanical Properties and Damage Constitutive Model of Saturated Sandstone Under Freeze-Thaw Action.

In order to investigate the impact of freeze-thaw damage on sandstone under the coupling of ground stress and pore water pressure, three types of porous sandstone were subjected to freezing at different negative temperatures (-5 °C, -10 °C, -15 °C, and -20 °C). Subsequently, hydraulic coupling triaxial compression tests were conducted on the frozen and thawed sandstone. We analyzed the effects of porosity and freezing temperature on the mechanical properties of sandstone under hydraulic coupling and performed nuclear magnetic resonance tests on sandstone samples before and after freezing and thawing. The evolution of the pore structure in sandstone at various freezing and thawing stages was studied, and a statistical damage constitutive model was established to validate the test results. The results indicate that the stress-strain curves of sandstone samples under triaxial compression after a freeze-thaw cycle exhibit minimal changes compared to those without freezing at normal temperature. The peak deviator stress shows a decreasing trend with decreasing freezing temperature, particularly between -5 °C and -10 °C, and then gradually stabilizes. The elastic modulus of sandstone with different porosity decreases with the decrease in freezing temperature, and the decrease is more obvious in the range of -5 °C~-10 °C, decreasing by 2.33%, 6.11%, and 10.5%, respectively. Below -10 °C, the elastic modulus becomes similar to that at -10 °C, and the change tends to stabilize. The nuclear magnetic porosity of sandstone samples significantly increases after freezing and thawing. The smaller the initial porosity, the greater the rate of change in nuclear magnetic porosity after a freeze-thaw cycle. The effects of freeze-thaw damage on the T2 distribution of sandstone with different porosity levels vary. We established a statistical damage constitutive model considering the combined effects of freeze-thaw damage, ground stress, and pore water pressure. The compaction coefficient K was introduced into the constitutive model for optimization. The change trend of the theoretical curve closely aligns with that of the test curve, better characterizing the stress-strain relationship of sandstone under complex pressure environments. The research findings can provide a scientific basis for wellbore wall design and subsequent maintenance in complex environments.

Effect of polyacrylate polymer on the mechanical and water retention properties of cemented soil: A multiscale investigation

Granitic residual soils (GRS) occupy substantial deposits in many regions but exhibit deficiencies restricting direct engineering applications. This study investigated polyacrylate (PA) polymer treatment to enhance the mechanical and hydrological properties of GRS. Triaxial tests evaluated the effects of PA content (0–3 %) on shear strength parameters under varied confining pressures. Soil-water retention characteristics were determined using pressure plate and filter paper methods. Microstructural analyses via scanning electron microscopy and pore attribute quantification furnished insights. Results showed PA increased peak deviator stress and cohesion in a content-sensitive manner up to an optimum 2 % dosage. A modified Duncan-Chang model accurately described the nonlinear stress-strain behavior. PA amplified water retention across the entire suction domain by elevating the air entry value attributed to microstructural changes. Morphological analyses indicated PA formed binding membranes consolidating particles with redistributed pore attributes towards stabler, load-resisting configurations. Quantitative links validated hypothesized mechanisms whereby optimized pore architectures directly translated bulk fabric cohesion and friction enhancement. Multi-scale evidence synthesized a self-consistent microscopic mechanism of PA-mediated pore network reconstitution systematically strengthening the granular framework. This study demonstrated polyacrylate modification optimizes key engineering properties of naturally deficient GRS, offering design guidance for sustainable geotechnical applications exploiting abundant residual soil resources.

Smart Transformer-Assisted Frequency Control Mechanism for RES Penetrated Power Systems Considering Metaheuristic-Based Secondary Controller

Abstract: The gradual replacement of conventional generators with variable renewable energy sources (RES) will reduce their online frequency regulation (FR) resources and degrade their overall frequency control capabilities. Although various inertia emulation methods exist, shaping load consumption is considered a more effective strategy during emergency conditions than under-frequency load shedding. Managing loads following frequency excursions can support grid stability owing to rapid power response. In this context, a Smart Transformer (ST)-based FR framework for a RES-penetrated power system is studied in this paper. The ST, with its distinctive features, effectively shapes the load profile through online load sensitivity identification-based control, aiding in the stabilization of grid frequency. This paper also proposes a tilt integral second-order double derivative (TIDD2) controller for a secondary loop whose parameters are optimized using the Learner Performance-based Behavior (LPB) algorithm. A thorough investigation reveals that the response from ST controlling the voltage-dependent load in the presence of TIDD2 controllers can greatly enhance system performance by damping oscillations and peak deviations. In addition, the performance of Proportional–Integral–Derivative and TIDD2 considering ST in the primary loop is compared to delineate the robustness of the LPB-based TIDD2 controller. It is found that the proposed control scheme offers greater controllability and flexibility, enhancing the system’s dynamic performance.

Study on Windage Response Suppression of Large-Span Transmission Tower-Line System Using a Spring-Pendulum Dynamic Vibration Absorber

Insulators and conductors in transmission line systems are susceptible to wind-induced movements, especially when insulators are closely positioned to transmission towers, potentially leading to electrical discharge. To address this issue, this study proposes a spring-pendulum dynamic vibration absorber (SPDVA) for windage suppression in transmission line systems. Using a finite element model based on an actual transmission line project, the study investigates SPDVA’s effectiveness in mitigating windage responses under varying wind speeds. The analysis considers mass and stiffness parameters to elucidate SPDVA’s suppression mechanism. The results indicate that SPDVA outperforms the additional heavy hammer method in suppressing insulator windage responses and also affects the peak acceleration response at the insulator’s bottom. Increasing stiffness initially enhances SPDVA’s suppression effectiveness on both peak and mean square deviation windage angle responses, peaking at 10 kN/m stiffness, while increasing the mass of the mass block also enhances suppression effectiveness.

Optimization of chemical engineering control for large-scale alkaline electrolysis systems based on renewable energy sources

In the context of renewable energy, dynamic control is crucial for large-scale alkaline water electrolysis systems. Under traditional Proportional-Integral-Derivative (PID) control, the system's temperature and impurity levels may exceed safe limits during sudden load changes, compromising system safety. Therefore, this study proposes a control strategy based on mathematical models of system temperature and impurities, including Model Predictive Control (MPC) for temperature and Optimal Curve Tracking (OCT) for impurities. The MPC controller offsets the disturbances in temperature caused by current fluctuations through state prediction, while the OCT controller ensures that impurity levels remain within safe limits. Real-time application of these control strategies is achieved through MATLAB-PLC communication, validating controller performance. Experimental results show that the MPC controller exhibits excellent dynamic response and stability in controlling the stack temperature, with a maximum temperature peak deviation of only 2.9 K and a temperature fluctuation range of 5.9 K. This represents a reduction of 1.6 K in peak deviation compared to traditional PID controllers and significantly decreases the temperature fluctuation range. The OCT controller also demonstrates good safety and stability in controlling hydrogen to oxygen (HTO) impurity levels, consistently maintaining the HTO content at the set upper limit of 1.5%, thereby expanding the safe operational range of the system and reducing the need for frequent adjustments to the system setpoints.

Study on shock wave load characteristics from condensed phase explosive detonations in deep-water explosions

This study investigates shock wave load characteristics from condensed phase explosive detonations in deep-water environments using a high-order compressible multiphase solver. Spatial terms of the solver are discretized by fifth-order weighted essentially non-oscillatory reconstruction in characteristic space, while a third-order total variation diminishing Runge–Kutta method is adopted to deal with the temporal terms. The level-set method captures multiphase interfaces, while a programed burn model describes detonation wave generation. Numerical and experimental validations focus on shock waves in explosives interacting with water. Validations across shallow and deep-water conditions align numerical results with theoretical and experimental values. The solver examines shock wave characteristics across varied charge masses and water depths, revealing peak pressure deviations under identical conditions. The numerical simulation results indicate that the similarity of shock wave loads in underwater explosions is evident not only in peak pressures but also in the pressure–time history curves. Through extensive comparative analysis of results, it has been found that existing formulas for calculating shock wave positive pressure durations are not applicable to deep-water explosions. The research findings and analytical methods presented in this paper can serve as crucial references for further studies on the characteristics of shock wave loads in deep-water explosions.

Influence of physical properties and shear rate on static liquefaction of saturated loess

Flow sliding instability of saturated loess slopes is a common geological hazard in loess areas of China. Previous studies have found that the occurrence of flow-slip loess landslides is closely related to static liquefaction and is controlled by physical characteristics and load conditions. In this work, we comprehensively study these influences of physical properties (i.e. initial pore structure, gradation, dry density) and shear rate on the static liquefaction of saturated loess through a series of consolidated undrained triaxial tests, and the effect mechanism of these related factors on the static liquefaction of saturated loess are also discussed. The results present that: (1) The peak deviator stress and the maximum pore pressure of the undisturbed loess are much greater than these of the remodeled one under each level of confining pressure (except 450 kPa). Further, the calculated liquefaction potential index (LPI) of undisturbed loess is much greater, indicating that undisturbed loess is more prone to static liquefaction due to the initial pore structure. (2) The lower the relative clay/silt content ratio of the saturated remodeled loess, the stronger the potential liquefaction ability. With the increase of the relative content of clay from 0.125 to 0.698, the stress-strain curve gradually transitions from strain softening to hardening. (3) The remodeled loess show the steady-state strength tends to continuously increase with the increase of dry density from 1.38 g/cm3 to 1.56 g/cm3, while the LPI increases first and then decreases, and the largest value appears when the dry density reaches to 1.44 g/cm3. The reason is that the value of 1.44 g/cm3 is the normal consolidated condition, which essentially reflects the potential liquefaction change during the transformation from under consolidated to over consolidated state.(4) The effect of shear rate on the stress-strain curve of remolded loess is not significant, but the peak strength and ultimate pore pressure show a trend of increasing and then decreasing with the increase of shear rate. There exists a “critical shear rate “of 0.1 mm/min reflecting the liquefaction of loess is more likely to occur when reaches to this critical value. (5) Based on the comparison of static liquefaction tests, the influencing factors of static liquefaction of saturated loess are: initial pore structure> gradation > dry density > shear rate. This study can provide a systematic evaluation for understanding the influencing factors of static liquefaction capacity of saturated loess (especially remolded one), and also has a reference for explaining the loess flow-sliding failure mechanism under disturbance conditions.

Ultra-stretchable triboelectric touch pad with sandpaper micro-surfaces for Transformer-assisted gesture recognition

Touch pad based on triboelectric nanogenerator are attracting attention in the field of wearable electronics and human-machine interaction. However, it is still a challenge to realize touch pads combining large-area metamorphic stretchability, high power triboelectric sensing, intelligent free-sliding recognition and availability in extreme environments. Here, we fabricate an ultra-stretchable triboelectric touch pad by integrating liquid metal and high performance hydrogel-based triboelectric sensor arrays, which achieves Transformer-assisted gesture recognition for drone flight direction control. The internal hydrogel electrode has great stretchability, electrical conductivity and anti-freeze properties. Encapsulated in Ecoflex with sandpaper micro-surfaces, it endows high triboelectric power density and pressure sensitivity. With screen-printed liquid metal, the integrated touch pad is fully ultra-stretchable and large-area strain stability. Combining Internet of Things, we build a Transformer-assisted human machine interface. Notably, slide gesture signal peak deviation is reduced by integral processing. The random free-sliding gesture signals are parsed by the Transformer algorithm with 96.83 % accuracy. Multi-threaded signal processing improves the response speed and throughput of the system. The accurate real-time gesture recognition for drone flight direction control in extreme environment is realized. This human machine interface can facilitate development of next generation intelligent remote interactive platforms.

Numerical modelling of multiple sclerosis: A tissue-scale model of brain lesions

Multiple Sclerosis (MS) is an autoimmune condition leading to the degeneration of brain tissue, occurring when the immune system attacks the myelin sheath surrounding axons of white brain matter thereby disrupting brain signals. This study aimed to evaluate how MS lesions alter stress distribution through grey and white brain matter with lesions (active, chronic, and inactive). A linear viscoelastic model represents the tissue-scale dynamic deformation and time dependency of brain tissue. A Prony series expansion was used to model viscous effects including stress relaxation. An elastic modulus, within the viscoelastic model, was either reduced by 11 % for active lesions, or increased by 35 % increase for inactive lesions. These material properties were then implemented to model healthy tissue, active, chronically inflamed, and inactive lesions. Finite element analysis enabled stress evaluation in response to a peak cyclic displacement of 0.5 mm (1 % strain) with the healthy model acting as a control model. Chronic lesions had the largest effect on stress induced, in terms of high (171 Pa) and low stress (108 Pa). Inactive lesions induced an increase in stress of 11 Pa with areas of low stress (105 Pa). Active lesions caused the least deviation in peak induced stress (7 Pa). In conclusion, a hierarchy in stress induced across the lesion types has been found, from highest to lowest: chronic, inactive and active, with potential implications for lesion progression. In conclusion, MS lesions within brain tissue should model lesions, avoid assuming homogeneity during degeneration, and should distinguish between active and passive lesions.

Investigation of temperature gradient effects and effective thermal inertia during adiabatic decomposition of substances with varying exothermic characteristics

To further study adiabatic parameters distortion, the adiabatic decomposition of 2,4-DNT, 20%DTBP, and 45%Glucose was systematically analyzed using thermal analysis calorimetry and numerical simulation methods. The study revealed the variation laws and influence mechanisms of the temperature gradient effects and thermal inertia in adiabatic systems. A numerical model for decomposition in a closed adiabatic system was developed by integrating the apparent kinetics into the CFD code. The results show that the temperature gradient effects during adiabatic decomposition initially increase and then decrease until reaching zero. The temperature gradient effects become more pronounced as the exothermic characteristics of substances increase. They are the most significant at the peak self-heating rate, with gradients of 182.4 °C·cm−1, 21.6 °C·cm−1, and 0.78 °C·cm−1, respectively. Specific data segments for adiabatic analysis should maintain α values below 0.138 for 2,4-DNT, 0.484 for 20%DTBP, and should utilize complete 100 % adiabatic data for 45%Glucose, aiming to mitigate potential distortion in adiabatic parameters. Furthermore, Фeff varies with the reaction, initially increasing and then decreasing in deviation from the theoretical value, with peak deviations of 60 %, 20 %, and 0.3 % for three substances, respectively. These findings lay the foundation for further optimizing the temperature gradient effects and establishing a dynamic Фeff correction model.

Strength behaviour of soil blended with two waste materials-fly ash and tire crumbs with cement

Abstract The rapid development in the economy has led to a growing need for electricity and automobiles, leading to the production of large quantities of fly ash (FA) and discarded tires. The safe disposal of these materials has become a significant problem. FA and scrap tyre derived material has some useful properties which can be beneficially used for enhancing the engineering properties of soil. Therefore, the study investigates the combined impact of FA and scrap tire-derived material on the stress-strain-strength behaviour of a fine-grained residual lateritic soil, incorporating a cementing agent. The research involves compaction tests followed by triaxial compression tests, where FA content added at an increment of 15% starting from 20% by weight of soil. The maximum FA content used in the mix is 50% by weight of soil. Tyre crumb (TC) which is a scrap tire-derived material, is also included in the study, with TC content ranging from 5% to 10% by weight. Additionally, 2% by weight of cement is added to each soil mix as a binding agent. Specimens are compacted in accordance with specific compaction parameters and subsequently cured for duration of up to 28 days. Strength tests are then carried out on those specimens to analyse their strength behaviour. This research primarily examines the shear strength characteristics of soil blended with FA, cement, and TC, emphasizing their geotechnical performance. Addition of 5% TC increases the peak deviator stress of cemented mix having 50% FA content from 1351 kPa to 2710 kPa at 300 kPa confining pressure and 28 days curing period. The inclusion of TC to soil-FA-cement blends is noted to significantly enhance shear strength when compared to mixes without tire crumb. Also, the stress-strain behaviour of soil is significantly influenced by addition of FA and cement in the presence of TC. Therefore, there is an ample scope of utilization of soil-fly ash-cement-TC mixes in geotechnical applications.

High-order allpass cascade-connected phase-system design utilizing fractional polynomial errors

ABSTRACT This paper proposes a nonlinear optimization method for designing a high-order recursive allpass digital phase system that comprises several cascade-connected second-order (SO) allpass sections. This method first splits a given phase design specification (approximation target) into a set of equal sub-specifications, and then the equal sub-specification acts as the ideal phase for each of the SO sections. Since an SO section can be designed via employing a linear programming to minimize a linear fractional error function, this splitting process generates an excellent starting point (good initial values for the coefficients of the cascaded SO sections) for further minimizing the overall approximation error. This paper first derives a wide variety of fractional polynomial error functions for designing cascade-connected allpass phase systems of different high orders, and then shows that a high-order cascade-connected allpass phase system can be designed by utilizing a nonlinear solver to minimize the peak deviation of such a fractional polynomial error. Using the derived fractional polynomial error functions in the system design enables the system designer to find an excellent starting point for further minimizing the approximation error and thus reach a convergent design solution. This paper first derives a set of fractional polynomial errors, and then adopts the eighth-order cascade-connected phase system design to exemplify the effectiveness of the fractional-polynomial-error-based design tactic. Furthermore, the stability of the cascade-connected high-order allpass system can be readily checked via confirming that all of the cascaded SO sections have their poles inside the unit circle in the complex plane.

Design and additive manufacturing of bionic hybrid structure inspired by cuttlebone to achieve superior mechanical properties and shape memory function

Lightweight porous materials with high load-bearing, damage tolerance and energy absorption (EA) as well as intelligence of shape recovery after material deformation are beneficial and critical for many applications, e.g. aerospace, automobiles, electronics, etc. Cuttlebone produced in the cuttlefish has evolved vertical walls with the optimal corrugation gradient, enabling stress homogenization, significant load bearing, and damage tolerance to protect the organism from high external pressures in the deep sea. This work illustrated that the complex hybrid wave shape in cuttlebone walls, becoming more tortuous from bottom to top, creates a lightweight, load-bearing structure with progressive failure. By mimicking the cuttlebone, a novel bionic hybrid structure (BHS) was proposed, and as a comparison, a regular corrugated structure and a straight wall structure were designed. Three types of designed structures have been successfully manufactured by laser powder bed fusion (LPBF) with NiTi powder. The LPBF-processed BHS exhibited a total porosity of 0.042% and a good dimensional accuracy with a peak deviation of 17.4 μm. Microstructural analysis indicated that the LPBF-processed BHS had a strong (001) crystallographic orientation and an average size of 9.85 μm. Mechanical analysis revealed the LPBF-processed BHS could withstand over 25 000 times its weight without significant deformation and had the highest specific EA value (5.32 J·g−1) due to the absence of stress concentration and progressive wall failure during compression. Cyclic compression testing showed that LPBF-processed BHS possessed superior viscoelastic and elasticity energy dissipation capacity. Importantly, the uniform reversible phase transition from martensite to austenite in the walls enables the structure to largely recover its pre-deformation shape when heated (over 99% recovery rate). These design strategies can serve as valuable references for the development of intelligent components that possess high mechanical efficiency and shape memory capabilities.

Electrical-feed-through elimination in micro-hemisphere resonator measurement based on mixed-frequency-excitation of different harmonic signals

To eliminate the electric feed-through introduced into the measurement of the micro-resonator by the electrical scheme, an improved mixed-frequency-excitation (MFE) method is proposed in this paper. Based on the electromechanical coupling and electric feed-through model of the micro-hemispherical resonator (MHR), the mechanism of suppressing the effect of electric feed-through on the resonant signal by the MFE method of different harmonic signals is analyzed theoretically. The MFE method can be divided into two kinds according to the frequency range. The feasibility of the method is verified by the actual measurement, and the multiplexing of the same oscillator can realize the MFE for the resonator. The measured results show that the resonant response of the micro-resonator can be measured by scanning frequency, and the signal-to-noise ratio can reach more than 10dBV. The resonant frequency of the resonator can be determined according to the position of the resonant peak. The characteristics and application range of the MFE methods of two different harmonic signals are deeply analyzed. It is revealed that the reason why the MFE in the high-frequency range causes the resonance peak deviation is due to the electrostatic negative stiffness introduced by the electric feed-through. The method and research content presented in this paper have a certain application prospect in the measurement of micro-capacitive resonators.

Enhancing geomechanical characteristics of calcium sulfoaluminate (CSA) cement-treated soil under low confining pressures

This study examines the efficacy of employing calcium sulfoaluminate (CSA) cement, an environmentally friendly binder, for enhancing the geomechanical characteristics of sand, particularly under low confining pressure conditions. A series of triaxial consolidated drained tests were performed on sand samples treated with varying content (5, 7, and 10%) of CSA cement and 10% ordinary Portland cement (OPC) under various low confining pressures (50, 100, 200, and 400 kPa). The test findings demonstrated the importance of cement content and confining pressure on the mode of failure, stress–strain and volumetric behavior, failure characteristics, and shear strength parameters of the treated quartz sand. After a curing period of 14 days, samples treated with 10% CSA cement exhibited a remarkable 212% increase in peak deviator stress and an 89% reduction in axial strain at failure, indicating higher initial stiffness compared to untreated samples under a 400 kPa confining pressure. Furthermore, the samples treated with 10% CSA exhibited higher peak deviator stress, initial stiffness, and strength development compared to those treated with 10% OPC. The scanning electron microscopy analysis provides insights into particle breakage and bond degradation processes, which increase with confining pressure in CSA-treated samples. Also, the mode of failure analysis reveals a transition from ductile to slightly brittle behavior with increasing cement content. Notably, the geomechanical properties of the treated material emphasized the significant impact of CSA cement on soil improvement. Thus offering a sustainable alternative for soil improvement in construction projects.

Experimental Study on Enhancing the Mechanical Properties of Sandy Soil by Combining Microbial Mineralization Technology with Silty Soil.

Currently, coastal sandy soils face issues such as insufficient foundation strength, which has become one of the crucial factors constraining urban development. Geotechnical engineering, as a traditional discipline, breaks down disciplinary barriers, promotes interdisciplinary integration, and realizes the green ecological and low-carbon development of geotechnical engineering, which is highly important. Based on the "dual carbon" concept advocating a green and environmentally friendly lifestyle, Bacillus spores were utilized to induce calcium carbonate precipitation technology (MICP) to solidify coastal sandy soils, leveraging the rough-surface and low-permeability characteristics of silty soil. The mechanical-strength variations in the samples were explored through experiments, such as calcium carbonate generation rate tests, non-consolidated undrained triaxial shear tests, and scanning electron microscopy (SEM) experiments, to investigate the MICP solidification mechanism. The results indicate that by incorporating silty soil into sandy soil for MICP solidification, the calcium carbonate generation rates of the samples were significantly increased. With the increase in the silty-soil content, the enhancement range was 0.58-3.62%, with the maximum calcium carbonate generation rate occurring at a 5% content level. As the silty-soil content gradually increased from 1% to 5%, the peak deviator stress increased by 4.2-43.2%, enhancing the sample shear strength. Furthermore, the relationship between the internal-friction angle, cohesion, and shear strength further validates the enhancement of the shear strength. Silty soil plays roles in adsorption and physical filling during the MICP solidification process, reducing the inter-particle pores in sandy soil, increasing the compactness, providing adsorption sites, and enhancing the calcium carbonate generation rate, thereby improving the shear strength. The research findings can provide guidance for reinforcing poor coastal sandy-soil foundations in various regions.

Improving performance of defect detection by setting skewed tolerance and joint tolerances in crimp force monitor

AbstractA Crimp Force Monitor (CFM) detects defects by whether the crimp force curve of the force sensor exceeds the set tolerance, with the goal of low defect miss rate and false alarm rate. In this study, typical defects made by hand are crimped with an automatic crimping machine together with good products to obtain continuous data of the crimping force curves and to process the data. For the peak and area deviations of the crimp force curve, the good products show skew‐normal distribution, and the defective samples show outliers and different deviation intensities in the positive and negative directions. Furthermore, by manually intervening in the batch production of multiple groups of defects and comparing the defect miss rate and false alarm rate of CFM with different tolerance settings, the peak skewed tolerance, joint loose tolerance and joint skewed tolerance tree settings can meet a low defect miss rate and low false alarm rate at the same time. The group test results verify the skew‐normal distribution of crimping force curve deviation rate and the characteristics of deviation intensities, providing reference for the tolerance setting of CFM in automated terminal crimping production.

Versatile Approach to Self‐Assembly of Surface Modified Nanoparticles into SERS‐Active Nanoclusters

AbstractA versatile method is invented to self‐assemble gold nanoparticles (GNPs) into nanoclusters (NCs) of various morphologies. By storing the particles in toluene, a highly non‐polar solvent, under conditions that ensure particle stability, the success rate of subsequent assembly can be enhanced. Additionally, conducting particle self‐assembly at a stirring speed of 200 rpm allows the NCs to maintain a spherical shape. The relative standard deviation (RSD) of Raman spectral peaks of multiple NCs used as surface‐enhanced Raman spectroscopy (SERS) substrates is calculated to be less than 10%, effectively addressing the issue of low repeatability when using NCs as SERS substrates. Furthermore, even at an analyte concentration reduced to 10−9 m, a SERS characteristic peak intensity of approximately 2 × 103 is measurable, demonstrating the high sensitivity of the assembled structures. Finally, by detecting SERS signals from NCs of varying sizes, the intensities of characteristic peaks tend to converge, eliminating the influence of morphology and size on SERS detection.