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We have previously shown evidence that some individuals seem to consistently minimize low back loads when lifting. while others do not. However, it is unknown why. Individual differences in ability to perceive relevant sensory information may explain differences in minimization of low back loads during lifting, consistent with considering load reduction in one's movement objective in an optimal feedback control theory framework. The purpose of this study was to investigate whether individuals' ability to perceive proprioceptive information (both force- and posture-senses) at the low back was associated with peak low back loads when performing generic or occupation-specific lifts. Seventy-two participants were recruited to perform 10 barbell (generic) and backboard (occupation-specific) lifts, while whole-body kinematics and ground reaction forces were collected. Peak low back compression and anteroposterior shear forces normalized to body mass were calculated as dependent variables. Both posture matching ability and force matching ability at the heavier force targets were associated with lower means and variability of peak low-back loads in both lift types, albeit with small effect sizes (R² 5.17). These findings support the utility of an optimal feedback control theory framework to explore factors explaining interindividual differences in low back loads during lifting. Further, this evidence suggests improving proprioceptive ability may be a useful strategy in lift training programs designed for workplace injury prevention. [ABSTRACT FROM AUTHOR]

Purpose: To compare the fracture resistance of five different groups of chairside CAD/CAM molar crowns fabricated from various lithium disilicate ceramic materials (LDC): one conventional precrystallized CAD/CAM LDC, two novel precrystallized LDCs, and one fully crystallized LDC tested both with and without optional sintering. Materials and Methods: A total of 60 chairside CAD/CAM lithium disilicate molar crowns (n = 12 per group) with 1.5-mm occlusal thickness and a 1.0-mm chamfer finish were designed and fabricated with a chairside CAD/CAM system (CEREC, Dentsply Sirona). The restorations were divided into five groups: (1) IPS e.max CAD; (2) Amber Mill; (3) Straumann n!ce; (4) Straumann n!ce with optional sintering; and (5) Supreme CAD. Restorations were cemented using conventional resin luting cement and primer system to 3D-printed resin dies. Bonded restorations were loaded for 100,000 cycles with 275-N force, and the load at break (LB) and peak load (PL) until fracture were measured. SEM images of fracture surfaces on the printed dies were obtained. Results: Fracture resistance was significantly different depending on the material. Supreme CAD showed the highest fracture resistance (LB: 1,557.2 N; PL: 1,785.8 N), followed by Amber Mill (LB: 1,393.0 N; PL: 1,604.2 N) and IPS e.max CAD (LB: 1,315.7 N; PL: 1,461.9 N). Straumann n!ce without (LB: 862.4 N; PL: 942.9 N) and with the optional sintering (LB: 490.4 N; PL: 541.0 N) showed significantly lower fracture resistance than the others. Conclusion: The fracture resistance of chairside CAD/CAM lithium disilicate molar crowns varied depending on the material, and the novel materials did not perform as well as the conventional equivalents. Fully crystallized lithium disilicate ceramic block materials showed lower fracture resistance than precrystallized counterparts and should be used with caution in the clinic, especially with optional sintering. [ABSTRACT FROM AUTHOR]

Crash boxes are safety elements generally made of metallic materials and mounted on the chassis of vehicles to prevent possible injuries to driver and passengers by absorbing the energy generated during a collision and ensuring integrity of vehicle. In order to save fuel and reduce harmful gases released into the environment, the proportion of metallic materials used in vehicles is decreasing and being replaced by composite materials. While composite materials are as durable as metallic materials, they are preferred because they are lighter. In this study, circular composites consisting of glass (S1), aramid (S2), carbon (S3), and hybrid combinations of aramid‐carbon‐glass (S4), carbon‐glass‐aramid (S5), and glass‐aramid‐carbon (S6), all with epoxy resin matrices, were produced using the vacuum infusion method and investigated. Crush parameters, maximum peak loads and specific energy absorption of hybrid tubes with different fiber types and winding order were compared. S3 tube had the best energy absorption performance among all samples of 257.288 Joules, while the worst energy absorption performance was obtained for S2 tube with 30.944 Joules. Among the hybrid samples, the best result was determined as 166.50 Joule with hybrid S5. Although the energy absorption capacities of hybrid composite tubes were close to each other, they had lower results for energy absorption and specific energy absorption than S1 and S3. For specific energy absorption, as with energy absorption, the best result was obtained with S3, while the lowest result was obtained with S2. Highlights: The aim of this study is to evaluate the performance of composite crash boxes.The effect of fiber type and hybridization was examined.Specific energy absorptions and maximum contact forces were compared.Cylindrical samples were produced by vacuum infusion.The variation of damage depending on fiber type was investigated. [ABSTRACT FROM AUTHOR]

The load‐bearing capacity and failure characteristics of composite structures are closely related to their dimensions. In this study, low‐velocity impact, ultrasonic non‐destructive testing, and compression after impact tests were conducted on composite laminates of varying widths to investigate the influence of size effects. Distinct impact response profiles and compression failure modes were characterized. The results indicate that under impact loading, the delamination threshold load (6700 N ~ 7200 N) and the knee‐point energy (40 J) are not affected by width. However, variations in width lead to differences in indentation depth, impact duration, peak load, delamination characteristics, and energy absorption. Furthermore, increasing impact energy further magnifies these differences. Under compression loading, wider laminates exhibit lower residual strength, with the influence of impact energy on residual strength decreasing as width increases. Importantly, the observed compression failure deformation mode transitions from localized buckling to widespread sub‐layer delamination‐induced compression failure. This suggests that changes in width alter the governing mechanical mechanisms of CAI failure. Consequently, the use of a single‐size laminate to represent both LVI and CAI processes is not recommended. Based on experimental results, the reliability of the equivalent damage method in predicting the residual compression strength of laminates of different widths was confirmed, providing valuable insights for practical engineering applications. Highlights: Assess the variations in the low‐velocity impact process of laminates with different widths.Evaluate the delamination damage of laminates after impacts by ultrasonic C‐scan techniques.Investigate the effect of variation in widths on the compression behavior of laminates after impact.Validate the feasibility of equivalent damage modeling for calculating residual strength. [ABSTRACT FROM AUTHOR]

Highlights This work proposes three Bouligand‐inspired layups to enhance low velocity impact (LVI) damage resistance and tolerance of convectional aircraft composite laminates. Two Bouligand‐like (HL and HL_S) and one hybrid design layup, merging conventional and Bouligand architecture (HYB), were produced by vacuum bag infusion. Their performance under LVI, at 13.5, 25 and 40 (J), and compression after impact (CAI) tests were evaluated and compared with a conventional aircraft multidirectional layup (LS) produced under identical conditions. Results demonstrated that, especially for the higher impact energy levels, both Bouligand‐like laminates consistently outperformed all the other configurations, exhibiting higher load bearing capacity (peak load) and energy absorption. Additionally, the rough and poorly defined interlaminar region of Bouligand‐like layups have showed to delay severe damage for higher loads and energies, dissipating all (at 13.5 J) or most of the impact energy (more than 50%) through subcritical damage mechanisms. Compared with LS laminate, Bouligand‐inspired layups postponed the onset of severe damage thresholds by up to 120% in load and 66% in energy (HL laminate) while developing smaller and more localized damages. The high number of fibers aligned in the loading direction of LS laminate led to better damage tolerance. Vacuum bag infused Bouligand‐like laminates consistently demonstrated superior performance than the conventional aircraft multidirectional layup, exhibiting higher load bearing capacity and energy absorption, particularly at higher impact energy levels; The rough and poorly defined interlaminar region observed in both Bouligand‐like layups demonstrated to play an essential role in the efficiency of damage mechanisms, dissipating all (at low impact energy levels) or more than 50% of impact energy on subcritical damages, such as translaminar matrix cracking; Compared with the conventional layup, HL Bouligand‐like laminate postponed 120% and 66% load and energy severe damage onset thresholds; The high number of fibers aligned in the loading direction of LS laminate led to better damage tolerance, despite the larger damaged areas observed. [ABSTRACT FROM AUTHOR]

Short-term residential load forecasting plays a crucial role in smart grids, ensuring an optimal match between energy demands and generation. With the inherent volatility of residential load patterns, deep learning has gained attention due to its ability to capture complex nonlinear relationships within hidden layers. However, most existing studies have relied on default loss functions such as mean squared error (MSE) or mean absolute error (MAE) for neural networks. These loss functions, while effective in overall prediction accuracy, lack specialized focus on accurately predicting load peaks. This article presents a comparative analysis of soft-DTW loss function, a smoothed formulation of Dynamic Time Wrapping (DTW), compared to other commonly used loss functions, in order to assess its effectiveness in improving peak prediction accuracy. To evaluate peak performance, we introduce a novel evaluation methodology using confusion matrix and propose new errors for peak position and peak load, tailored specifically for assessing peak performance in short-term load forecasting. Our results demonstrate the superiority of soft-DTW in capturing and predicting load peaks, surpassing other commonly used loss functions. Furthermore, the combination of soft-DTW with other loss functions, such as soft-DTW + MSE, soft-DTW + MAE, and soft-DTW + TDI (Time Distortion Index), also enhances peak prediction. However, the differences between these combined soft-DTW loss functions are not substantial. These findings highlight the significance of utilizing specialized loss functions, like soft-DTW, to improve peak prediction accuracy in short-term load forecasting. [ABSTRACT FROM AUTHOR]

In ITER, disruption-born runaway electrons (REs), unless mitigated, are expected to form a several Mega-Ampere beam that ultimately intercepts the first wall leading to melting of the plasma facing components. Developing a successful mitigation strategy therefore requires modeling that takes into account the coupling between REs and the MHD during the formation and termination of the beam, along with estimates for the wall loads that can be compared to design values. Using the JOREK code, this work aims to provide the latter by presenting a novel model for collisions between REs and the wall and applying it to a beam termination scenario in ITER. To this end, the transport of REs is modeled by tracing particles in the fields calculated by preceding simulations of the disruption event where REs were treated in the fluid picture and self-consistently coupled to the MHD. The resulting heat loads are found to be highly localized in both the poloidal and toroidal directions, with 3D features also playing an important role in the appearance of hot spots. Peak loads were on the order of 10 7 − 10 8 J m 2 . The load distribution was found to only be weakly sensitive to the initial phase space distribution of the REs when decoupled from the fields, while modifying properties of the underlying MHD yielded notable differences in wetted area and peak loads, in particular for cases with higher resistivity. [ABSTRACT FROM AUTHOR]

To evaluate structural damage and loosening of abutments placed on narrow diameter implants after cyclic fatigue. Sixty Morse taper narrow diameter implants (Neodent, Brazil) received two types of abutments (1PA- one-piece abutment or 2PA- two-piece abutment), which were randomly divided into 3 fatigue experiments (n = 10). The implants were placed into a customized supporting holder and a software-assisted digital torque wrench secured the manufacturer recommended torque for each abutment. Cone beam computed tomography (CBCT) scans were acquired, before and after fatigue, and post-processed (software e-Vol DX) to assess damage and abutment displacement. The boundary fatigue method was adapted to use 2 × 106 cycles, 2 Hz of frequency and constant peak load of 80 N (first experiment) that varied according to the failure rate of previous specimens (second and third experiments). Failure was evaluated using CBCT scans and removal torque values. Data were used to estimate long-term torque degradation, probability of failure and Weibull modulus (software ALTA PRO9). All 2PA specimens became loosen independently of the applied fatigue load, and structural bending was observed in 14 abutments. Eight 1PA got loosen during the fatigue experiment. The Weibull analysis showed a lower modulus (m = 1.0; 0.7, 1.4) for 1PA than for 2PA (m = 2.6; 2, 3.4) resulting in longer predicted lifetimes and slower torque degradation for 1PA than for 2PA specimens. 1PA showed greater long-term survival probability than 2PA. Predicting the lifetime and mechanical behavior of implant-abutment systems are useful information to clinicians during the decision-making process of oral rehabilitations. • The abutment type influences the survival probability of the implant-abutment system. • The applied method can predict the lifetime and long-term behavior of the systems. • Improved CBCT images can assist on diagnosing loosening and damage of implant-abutment. [ABSTRACT FROM AUTHOR]

This study investigates the effects of palm fibers on the seismic behavior of adobe walls. Towards this, six wall panels, with dimensions of 1000 × 900 × 200 mm3 were constructed with different fiber contents. Seismic loading was simulated through incrementally increasing cyclic loading reversals combined with a constant vertical stress of 0.3 MPa. The results are described in terms of failure mechanism, load-displacement hysteretic curves, and other prominent structural factors. It was found that adding palm fibers can increase the peak load and displacement ductility by up to 37 and 39%, respectively. [ABSTRACT FROM AUTHOR]

Cement-stabilized macadam is a type of heterogeneous and discontinuous material. To study the mesomechanical behavior of cement-stabilized macadam particles, a discrete-element model of cement-stabilized macadam is constructed according to the random distribution theory and certain porosity and gradation. The constitutive relations of contact between particles may be linear contact, linear bonding, and linear parallel bonding. The stress–strain, crack propagation, particle velocity, stress transfer, and force chain distribution of cement-stabilized macadam were analyzed after comparing the results of simulated uniaxial compression with laboratory tests. The results of uniaxial compression calculations for cement-stabilized macadam were in good agreement with the experimental data. At the beginning of loading, the upper/lower particles moved toward the middle; at the peak loading stage, the particle movement was mainly in the vertical direction; and at the final of loading, the particles mainly moved to the sides. With the increase in loading, the contact force between particles became larger and larger. At the loading peak, the contact force between particles reached the maximum value, and the normal and tangential contact forces of particles were not evenly distributed. Microcracks at each stage were mainly vertical cracks, most of which were located at 70–110°. In this paper, the uniaxial compression test of cement-stabilized macadam was dynamically simulated using discrete-element theory, and the mesoscopic structure and dynamic variation process of parameters were analyzed. It provides references for the study of damage of heterogeneous and discontinuous quasi-brittle materials. [ABSTRACT FROM AUTHOR]

A large volume of solar energy dissemination in a supply grid originates extreme variations in the load, resulting in a duck-form load arc that can cause stability issues. Also, the cost of energy consumption is found to vary between the off-peak and peak loads observed in the duck-shaped load curve. Accurate load forecast and demand response program is a key task for duck curve management in a distribution structure. Hence, this work proposes a Demand Response (DR) program using deep learning neural networks namely Long Short-Term Memory (LSTM). The proposed DR program is implemented in a modified 12 bus radial distribution network for duck curve management, where voltage stability is taken care of simultaneously minimizing the electricity cost in an energetic pricing environment. LSTM is used for forecasting the load and linear programming is used for load shedding. Therefore, this paper resolves the dual aims of flattening the duck-shaped load arc and minimizing electricity costs by combining them into a single objective function. [ABSTRACT FROM AUTHOR]

To investigate the effects of thermal treatment and loading conditions on the crack initiation and propagation characteristics of quartz‐diorite, mixed mode I + II fracture tests were conducted by using three‐point bending (TPB) specimens. The numerical model, established on ABAQUS, couples the initial fracture toughness criterion and cohesive zone model to predict the crack initiation and propagation. The effects of thermal treatment and loading conditions on the crack propagation process, crack resistance curve, fracture path, and some fracture parameters at peak load have been analyzed and discussed. The results demonstrate that the thermal treatment has an obvious influence on the crack resistance curve of the specimen. The crack of the specimen will be dominated by the mode I fracture component with crack extension. The numerical results also show that the temperature and loading condition affect the crack length and fracture toughness at peak load. Highlights: The loading mode of the specimen changes to mode I loading with crack growth.Thermal treatment decreases the fracture resistance of rock under the same crack length.Mode I fracture resistance at peak load is insensitive to the variation of loading mode. [ABSTRACT FROM AUTHOR]

Peak power load forecasting is a key part of the commercial operation of the energy industry. Although various load forecasting methods and technologies have been put forward and tested in practice, the growing subject of tolerance for abnormal accidents is to develop robust peak load forecasting models. In this paper, we propose a robust smooth non‐convex support vector regression method, which improves the robustness of the model by adjusting adaptive control loss values and adaptive robust parameters and by reducing the negative impact of outliers or noise on the decision function. A concave‐convex programming algorithm is used to solve the non‐convexity of the optimization problem. Good results are obtained in both linear regression model and nonlinear regression model and two real data sets. An experiment is carried out in a power company in Jiangxi Province, China, to evaluate the performance of the robust smooth non‐convex support vector regression model. The results show that the proposed method is superior to support vector regression and generalized quadratic non‐convex support vector regression in robustness and generalization ability. [ABSTRACT FROM AUTHOR]

The paper investigates the behavior of glass‐fiber reinforced polymer (GFRP) reinforced concrete columns with integrated steel spirals (hybrid reinforcement). Six concrete columns were tested under eccentric axial loading, resulting in failure due to bending. Columns with outer steel longitudinal bars experienced steel yielding at peak loads, while those with GFRP outer rebars failed due to concrete crushing. The results revealed that using GFRP as outer longitudinal bars led to peak loads 3–10% lower compared to columns with steel rebars. Inner confinement by steel spirals increased the load‐carrying capacity. Additionally, columns with inner tubular steel exhibited greater strength than those with steel spirals, indicating a slightly enhanced confinement effect. A finite element model was developed to analyze structural behavior, considering both material and geometric nonlinearity. The model's accuracy was validated by comparing predictions with test results. Parametric analysis from the nonlinear FE model showed that eccentricity significantly impacted column load‐carrying capacity. Increasing inner confinement area and the number of inner longitudinal bars improved structural stiffness and load‐carrying capacity. Furthermore, a simplified theoretical method was proposed. Comparison between experimental failure loads and theoretical predictions revealed differences within 20%, indicating satisfactory reliability of the proposed method. [ABSTRACT FROM AUTHOR]

Extrusion tests were conducted on recycled coarse aggregate concrete with circular steel tubes (RCCST, 100% replacement of recycled coarse aggregate) to investigate the impact of freeze–thaw cycles on bond properties. RCCST samples were subjected to 0, 25, 50, 75, 100, 125 and 150 freeze–thaw cycles and their bond properties were then compared with those of natural coarse aggregate concrete with circular steel tubes (NCCST) after 0, 100 and 150 freeze–thaw cycles. The experimental results indicate that freeze–thaw cycling damages the internal structure of RCCST, causing a significant decrease in interfacial bond strength with an increase in the number of freeze–thaw cycles. Freeze–thaw RCCST exhibits lower peak load and higher peak slip compared to NCCST, with increases of 25.2%, 73.2%, and 70.3% after 0, 100, and 150 freeze–thaw cycles, respectively. Regression analysis was used to derive an exponential equation that describes the relationship between longitudinal strain and strain gauge position. Additionally, a segmented fitting method was employed to obtain an expression for the bond slip of the freeze–thaw RCCST with a circular steel pipe. [ABSTRACT FROM AUTHOR]

In order to study the mechanics, acoustic emission (AE) and electromagnetic emission (EME) response law of bursting liability coal at different loading rates, uniaxial compression tests were carried out on coal mass from Konggu Coal Mine. The corresponding relations among mechanical properties, AE and EME signals in the process of coal failure under loading were analyzed, and the energy evolution law of coal failure with bursting liability under loading rate was discussed. The results show that within a certain range of loading rate, the higher the loading rate, the higher the compressive strength and peak load of bursting liability coal, and the shorter the time for coal to reach the peak load. Under different loading rates, the mechanics, AE and EME signals of coal samples can be well corresponded. When the loading rate is low, the number of blocks destroyed of coal sample is large and the block size is relatively small, and the blocks are mainly scattered around the test platform. When the loading rate is high, the number of damaged blocks is relatively small and the block size is relatively large, and the blocks are far away from the test bench. When loading at a low rate, the internal cracks in coal can be fully developed and connected, and the energy release rate is relatively uniform in the process of loading and failure of coal sample. In the case of high loading rate, the energy release rate of coal sample in the loading process is much smaller than that in the moment of failure. Combining the above test results with the actual situation of the working face, it can be concluded that the total energy stored in the coal of fast mining increases and the threshold of impact decreases compared with that of slow mining. Therefore, under the disturbance of external dynamic load, rapid mining is more likely to induce rock burst. [ABSTRACT FROM AUTHOR]

This paper examines the use of Phase Change Materials (PCM) in Building-Integrated Photovoltaic (BIPV) systems. To assess the performance of BIPV–PCM systems, the study employs a Strengths, Weaknesses, Opportunities and Threats (SWOT) analysis. The study features the advantages of using PCMs with BIPV envelopes. The benefits include lower heating and cooling requirements, shifted peak loads and increased thermal comfort. However, there are several challenges like heat loss and lower energy efficiency which needs to be addressed. Further, the potential for reduced PCM efficiency over time is recognized. The paper concludes by recommending further research on alternative PCM placement strategies, enhanced PCM formulations, gypsum board integration and the evaluation of PCMs combined with nanoparticles. [ABSTRACT FROM AUTHOR]

When modelling the anchorage performance of rebars with the tri-linear law, the calculation process of the load–deformation relation is complicated. The reason is that when the rebar–grout interface entered the elastic–softening–debonding stage, the softening section length and debonding section length vary simultaneously. To solve this issue, this paper proposes an enhanced numerical calculation method. When the rebar–grout interface entered the elastic–softening–debonding stage, the softening section length was fixed to a specific value. One loop function was created to calculate the debonding section length. With this method, the number of iteration calculations significantly decreased. The credibility of this calculation method was confirmed with experimental results. Two case studies were conducted to compare the load–deformation relation obtained with the original calculation method and enhanced calculation method. The results showed that good consistency existed between the results obtained by those two methods. This finding can significantly improve the calculation efficiency when studying the anchorage performance of rebars. Moreover, this paper provides new insight for users to optimise the modelling process of rebars. [ABSTRACT FROM AUTHOR]

In this study, the fracture behavior of notched concrete beams produced with concrete strength from 25 to 100 MPa and steel fiber volume ratio from 0 to 1.5% were experimentally investigated under three-point loading. The digital image correlation method was adopted to determine the full-field deformation map on the beam surface. Test results were evaluated concerning vertical deflection versus CMOD, peak load fracture energy, effective crack length and unstable fracture toughness. Based on the characteristic length of specimen, an empirical relation was developed for the estimation of effective crack length, which yielded results close to those of two parameter model. [ABSTRACT FROM AUTHOR]

Aiming at the problems of small thermal power units and biomass mixed combustion units with small generation loads and insufficient primary frequency modulation capability, which cannot be connected to the virtual power plant, this paper adopts a variety of flexibility retrofit methods for the units and explores the peak load capability of the units. Then, multiple units are coupled, and the unit coupling scheme with better economy and environmental protection is screened using comprehensive evaluation indexes. While evaluating the peaking load space of multiple unit coupling, the units' primary frequency regulation capability and new energy consumption capability are improved. According to the calculation results, the low-pressure cylinder zero-output retrofit has the largest peaking potential among different technical paths, in which unit #3 has 27.55 MW of peaking space. The compression heat pump decoupling retrofit has the best economy, in which the daily profit of unit #3 increases from 0.93 to 1.02 million CNY with an increase of 0.09 million CNY. After the unit has been retrofitted with steam extraction, the three units can be coupled to meet the national feed-in standards. The multiple unit coupling can accommodate up to 203.44 MW of other energy sources while meeting the standard. [ABSTRACT FROM AUTHOR]

The economy of a country is directly proportional to the power sector of that country. An unmanaged power sector causes instability in the country. Pakistan is also facing this phenomenon due to uncontrolled power outage and circular debt. Pakistan's power sector is analyzed as a case study to find out the root cause for the unmanaged power sector and for proposing the most effective data-driven solution. After a literature review and discussion with domain experts, it was found that inaccurate power demand forecast is one of the main reasons for power crisis in Pakistan. Under-forecasting caused load shedding, and over-forecasting increased circular debt due to idle capacity payments. Previously, traditional statistical methods were used for power demand forecasting. The multiple linear regression model that is being used since 2018 (IGCEP) uses features such as previous year load and demographic and economic variables for long-term peak power demand forecasting till 2030. The problem is that the independent variables used in existing models are manipulated and cause a gap between actual and forecasted power demand. Moreover, even yearly peak power demand is not absolutely linear in nature; hence, it is necessary to apply AI-based techniques that can handle nonlinearity effectively. Not using system-generated data, not using the most appropriate features, not using an appropriate forecasting time horizon, and not using the appropriate forecasting model are main reasons for inaccurate peak power demand forecasting. The issue can be resolved by forecasting monthly peak power demand for the next 5 years by using the National Power Control Center's (NPCC) system-generated data. Accurate monthly peak load forecasting leads to accurate yearly peak power demand. The monthly peak load forecasting strategy not only helps in managing operational issues of the power sector such as fuel scheduling and power plant maintenance scheduling but also guides decision-makers toward power and transmission expansion or contraction in the long term. More accurate monthly peak power demand forecasting can be achieved by applying nonlinear AI models in a comprehensive dataset comprising new engineered features, climate features, and the number of consumers. All these features are mostly system-generated and cannot be manipulated. As a result, the accuracy is improved and the results are more reliable than those of the existing models. The new features can be engineered from recent monthly peak load data generated by the system operator (NPCC). Climate features are collected from the Meteorological Department of Pakistan through sensors or database connectivity. The number of electricity consumers can be extracted from NEPRA's state-of-industry report. All three datasets are combined on a common key (month-year) to a comprehensive dataset, which is passed through different AI models. In the experimental setup, it is found that support vector regression (SVR) produces the most accurate results, with an R-square of 99%, RMSE of 28, and MAPE of 0.1355, which are the best results compared to the literature reviewed. [ABSTRACT FROM AUTHOR]

With regard to deep mining in metal mines, an investigation into the failure mode of deep fractured rock masses and their corresponding acoustic emission signal characteristics is conducted via uniaxial compression tests. Subsequently, a fractal damage renormalization group mechanical model is developed to explain the behavior of those fractured rock masses. Employing the bonded block model (BBM) numerical simulation method, fracture process in synthetic rock samples is analyzed, thereby validating the efficacy of the mechanical model. The numerical simulations highlight the critical role of fractures expansion in underlying the deterioration of rock mass strength. As the peak load decreases, the fracture fractal dimension increases, leading to a significant 14.2% reduction in compressive strength accompanied by an approximate 8.7% rise in average fracture fractal dimension. A comparative analysis of tetrahedral and voronoi block synthetic rock samples reveals the tetrahedral block samples exhibit a superior ability to depict the fracture behavior of fractured rock masses. Specifically, they offer a more accurate simulation of acoustic emission characteristics and failure modes. Furthermore, variations in the fracture fractal dimension with respect to the hole defect's position are observed, with the maximum value occurring along the vertical axis of the hole defect. This observation underscores the potential utility of visually monitoring deep rock fracture dynamics as an effective mean for quantitatively evaluating fracture damage and strength degradation in deep rock formations. [ABSTRACT FROM AUTHOR]

This paper presents a highly efficient dual-mode HV (high voltage) buck converter which operates at both light and heavy load currents. To improve the conversion efficiency at two different load conditions, a dual-mode design composed of pulse width modulation (PWM) and pulse frequency modulation (PFM) were implemented using TSMC 0.5- $\mu $ μ m HV CMOS process. The chip area is 2038.05 $ \times $ × 1689.85 $\mu $ μ m2, while the input voltage ranges from 12 V to 15 V. A 92.95% peak efficiency at a load current of 10 mA was achieved based on on-silicon measurement results. [ABSTRACT FROM AUTHOR]

In the paper, the eccentric compression behavior of the truss-reinforced cross-shaped concrete-filled steel tubular (CCFST) column is investigated. A total of eighteen CCFST columns were tested under eccentric compression, and the key test variables included the reinforced truss node spacing (s = 140 mm and 200 mm), slenderness ratio (λ = 9.2, 16.6, and 23.1), and eccentricity ratio (η = 0, 0.08, and 0.15). The failure mode, deformation characteristic, stress distribution, strain distribution at the mid-span of the steel tube, and the eccentric compression bearing capacity were assessed. The results show that due to the addition of reinforced truss, the steel plates near the mid-span of eccentrically compressed CCFST columns experienced multi-wave buckling rather than single-wave buckling after the peak load was reduced to 85%, and the failure mode of concrete also changed from single-section to multi-section collapse failure. Comparisons were made with the unstiffened specimen. The ductility coefficient of the stiffened specimen with eccentricity ratios of 0.08–0.15 and node spacings of 140 mm~200 mm increased by 70~83%, approaching that of the multi-cell specimens with an increasing steel ratio of 1.8%. In addition, by comparing the test results with the calculation results of four domestic and international design codes, it was found that the Chinese codes CECS159-2018 and GB50936-2014, and the Eurocode 4 (2004) can be better employed to predict the compression bearing capacity of truss-reinforced CCFST columns. [ABSTRACT FROM AUTHOR]

The stability of the roof in coal mining plays a crucial role in ensuring safe excavation. After coal extraction, the roof experiences complex and unbalanced stress conditions, leading to diverse roof failure behaviors, particularly in the case of thick roofs. This study examines the failure behaviors of roofs with different thicknesses through a combination of on-site measurements, physical modeling, and numerical modeling. The on-site results indicate that the failure of thick roof leads to larger magnitudes, increased magnitude variance, and energy compared to thin roof. A self-developed three-dimensional roof fracture experimental platform was utilized to conduct loading experiments on roofs with different thicknesses. The experimental results reveal that roof thickness significantly impacts peak load, deformation characteristics, crack patterns, and acoustic emission (AE) signals. Thin roof failure only generates tensile cracks, while thick roof failure produces both tensile and shear cracks. This suggests that an increase in roof thickness leads to a transition in the roof's failure mode from pure tensile failure to tensile-shear mixed failure or shear failure. The energy of AE events has a threshold. When below this threshold, more AE events occur for thin roofs, and when above it, thick roofs exhibit more AE events. The digital image correlation (DIC) results and AE location indicate roof failure initiates from the upper surface of the roof, where "O" shaped cracks form around the periphery, followed by gradual development of cracks on the lower surface. Thin roofs exhibit regular "X" shaped crack on lower surface, while thick roofs display additional branching and inflection points based on "X" shaped crack on lower surface. Numerical modeling using four polygonal particle roof models confirms the influence of roof thicknesses on peak load, deformation, and crack distribution, aligning with experimental and on-site results. These findings offer valuable theoretical support for controlling the stability of surrounding rock conditions in the presence of different roof thicknesses. Highlights: Roof thickness significantly affects coal mine safety, leading to diverse roof failure behaviors. On-site measurements, physical experiments, and numerical simulations reveal insights into roof behaviors. An experimental platform was established to explore the correlation between roof thickness and failure behavior. Thicker roofs exhibit higher peak loads, reduced deflection, complex crack propagation, and a tensile-shear mixed failure or shear failure. Numerical models of polygonal particle roofs further corroborate the impact of roof thickness on failure behavior, offering practical support for coal mine stability. [ABSTRACT FROM AUTHOR]

This study utilizes the large eddy simulation model (LES) and a synthetic method based on the Fourier technique called consistent discrete random flow generation (CDRFG) to analyze the peak aerodynamic loads on heliostats due to the atmospheric boundary layer. With the CDRFG technique, key flow parameters, including mean velocity profile, turbulent intensities, integral length scales, and turbulent spectra generated in wind tunnels, can be replicated while also satisfying the divergence-free condition. A three-facet heliostat with an elevation angle of α = 45 deg and the rear aligned to the inflow was analyzed. The heliostat behaves like a lifting surface in this orientation, accentuating the aerodynamic effect. The methodology proposed in this study can accurately reproduce flow statistics and predict the peak loads. Compared to experimental data, differences of 2.62% for drag, 7.43% for lift, and 11.0% for overturning were observed. Furthermore, the simulation reveals the generation of wingtip vortices on the sides of the heliostat, which contribute to the aerodynamic load. Overall, this technique has been demonstrated to be effective in replicating the atmospheric boundary layer and predicting the aerodynamic coefficients of heliostats. [ABSTRACT FROM AUTHOR]

With cores of the hexagonal honeycomb (HH), staggered corrugated lattice (SCL), bidirectional corrugated lattice (BCL), reinforced hexagonal honeycomb (RHH), and reinforced staggered corrugated lattice (RSCL) made by cutting, bonding, arranging and weaving the trapezoidal corrugation (TC) formed by mold hot pressing, six types of composite sandwich panels of the same macro size were proposed. The failure processes of the six sandwich panels in three-point bending experiments were compared and analyzed, and the effects of core configuration and reinforced stiffener on the bending response were evaluated. A general analytical model was established to predict the bending stiffness and failure mode of six sandwich panels, which was also visually presented by a three-dimensional numerical model. The numerical and experimental results validated the effectiveness of the analytical model. The effects of ply parameters and corrugated sizes on bending responses were studied by a combing application of experiment, analytical and numerical models. The three-dimensional failure mechanism maps were displayed to evaluate the failure mode and failure load. The longitudinal discontinuity of the bonding zone of the core could significantly weaken the bending performance and bonding strength of BCL, SCL, RSCL, and HH. The peak load of SCL and HH was enhanced by 45.97% and 60.29%, respectively, by setting stiffeners. Both RHH and TC could achieve bending stiffness of more than 3.5 kN·mm−1, while the failure load of the latter could be up to 25 kN. The design parameter space of bending stiffness, failure load with respect to ply orientation angle, core wall thickness, corrugated web angle, and horizontal segment length was provided intuitively. [ABSTRACT FROM AUTHOR]

Interlayer hybrid foldcore sandwich structures have been introduced in this study. Both facesheets and foldcores were hybridized in the same ply sequence with two layers of plain woven carbon (C) and two layers of satin woven glass (G) fiber prepregs (Carbon-to-Glass ratio 1:1). Foldcore sandwich structures with six-ply combinations were designed including two symmetric layups (GCCG and CGGC) and four asymmetric layups (CGCG, GCGC, CCGG, and GGCC). The static compression and low-velocity impact performance of foldcore sandwich structures of different ply sequences were investigated. A user-defined material subroutine (VUMAT) was employed to characterize the damage evolution of composite materials based on selected failure criteria. The findings revealed that hybridization was effective in enhancing its energy absorption value of pure carbon fiber foldcore sandwich structures in terms of static compression performance. The damage degree of the interlayer hybrid foldcore sandwich structures increased gradually with the increasing impact energy. Moreover, the damage of facesheet was mainly caused by fiber tensile, matrix tensile damage and delamination, and damage of foldcore was mainly delamination. GCGC sandwich panel with asymmetrical cross-ply sequence has the optimal load bearing capacity, and CGGC sandwich panel with symmetrical layup has a strong energy absorption capacity under high-energy impact load. The foldcore sandwich structure showed smaller peak load, longer crushing distance, and more energy absorption value under larger oblique impact angle. The simulation and experimental results show good agreement in peak force, maximum energy absorption, and damage mode. [ABSTRACT FROM AUTHOR]

This paper employs the user-defined function method to define the boundary and analyzes the effects of various ship speeds, wave parameters, and bow structural loads on deck and hull motion responses. When the ship has a wave slamming phenomenon, the water body's height, its response to the slamming load on the deck and superstructure, and hull motion improve the seakeeping performance of the hull model. Analysis of simulation results reveals that peak slamming loads generally increase with higher speeds and wave heights. As speed increases, results oscillate irregularly, affecting the nonlinearity of the slamming load. Additionally, when the wave slamming occurs, the slamming load near the superstructure of the bow model is relatively small. Finally, the numerical modeling method is used to modify the bow area structure, and the simulation analysis is carried out under different incident waves and speeds. The influence of the drift angle on the superstructure is discussed, and beneficial suggestions are provided for the future studies of waves on deck. [ABSTRACT FROM AUTHOR]

A thermomechanical finite element (FE) model was used to examine the effects of resistance spot welding (RSW) current intensity, time, and electrode force on the distribution of temperatures and the size of nuggets of IN-625 superalloy sheets. In order to evaluate and optimize the mechanical properties of RSW welded IN-625 alloy, a procedure was developed based on simulation results. A taguchi L9 experimental design was used to study the mechanical properties of welded samples as a function of peak load, failure mode, and energy. According to the findings, joint fracture modes and strength are significantly influenced by process parameters. Consequently, welding current, electrode force, and welding time all had significant impacts on the shear strength of IN-625 Alloy spot welding joints, with impacts of 62.05%, 24.06%, and 12.84%, respectively. [ABSTRACT FROM AUTHOR]

This study presents an implementation of optimal Diesel Generator (DG) operation on a university campus, taking several strategies for managing the campus Micro Grid (MG) into account. The actual dataset is used to solve the Mixed Integer Linear Programming (MILP)-based energy management optimization problem of a campus MG consisting of a Utility Grid (UG), DG, and Wind Turbine (WT). The objective is to operate the campus MG more economically under the Time of Use (ToU) tariff by considering reliability, carbon balance, and peak load shaving. Five case studies are conducted at a university campus using a deterministic approach to validate the performance of the proposed method. The results show that the proposed method is economically beneficial by an average of 26.41% while keeping the carbon balance almost constant and decreasing the peak load by 15.8%. To summarize, the findings of this study demonstrated the superiority of the proposed method in real-world applications with no investment by economical operation of the DG considering the carbon balance of the campus. [ABSTRACT FROM AUTHOR]

Peak load forecasting plays an important role in electric utilities. However, the daily peak load forecasting problem, especially for holidays, is fuzzy and highly nonlinear. In order to address the nonlinearity and fuzziness of the holiday load behaviors, a grammatical evolution-based fuzzy regression approach is proposed in this paper. The proposed hybrid approach is based on the theorem that fuzzy polynomial regression can model all fuzzy functions. It employs the rules of the grammatical evolution to generate fuzzy nonlinear structures in polynomial form. Then, a two-stage fuzzy regression approach is used to determine the coefficients and calculate the fitness of the fuzzy functions. An artificial bee colony algorithm is used as the evolution system to update the elements of the grammatical evolution system. The process is repeated until a fuzzy model that best fits the load data is found. After that, the developed fuzzy nonlinear model is applied to forecast holiday peak load. Considering that different holidays possess different load patterns, a separate forecaster model is built for each holiday. Test results on real load data show that an averaged absolute percent error less than 2% can be achieved, which significantly outperforms existing methods involved in the comparison. [ABSTRACT FROM AUTHOR]

This article presents the results of a study on the feasibility of a Rigid Overhead Conductor-rail System (ROCS) for a Mass Rapid Transit (MRT) system using 750 V DC power based on a carrying capacity transport-supply voltage level relationship. In particular, peak load conditions often cause serious problems of voltage drops occurring along the contact line, affecting the reliability, flexibility, system safety, and efficiency performance of the MRT system. The potential at the pantograph of a train on the segment of power supply depends significantly on the structure of the traction power supply network, contact network type, and voltage level. Recently, there have been studies on the dynamics of ROCSs under the impact of train motion, thereby applying the design to several railway systems in the world in specific conditions such as tunnels, stations, or viaducts. To consolidate the advantages of this trend, this paper studies the operating voltage of an ROCS in a full-line MRT system with a voltage level of 750 V DC belonging to the third rail. Matlab R2017b/Railway Systems is a reliable software for simulating and analyzing the necessary data. The results exhibit the feasibility of the designed ROCS. The system has a passenger carrying capacity of up to 90,000 passengers per hour per direction (p/h/d) under both normal and fault conditions. In this case, this capacity is achieved with a single-end feed at a distance of 2 km from a Traction Power Station (TPS), with the minimum feeder voltage at the pantograph point being 532.7200 V. The lowest operational feeder voltage of the system is 523.6667 V, supplied from a double-end feed at a distance of up to 5 km from the TPS. [ABSTRACT FROM AUTHOR]

In order to address the challenges posed by the integration of regional electric vehicle (EV) clusters into the grid, it is crucial to fully utilize the scheduling capabilities of EVs. In this study, to investigate the energy storage characteristics of EVs, we first established a single EV virtual energy storage (EVVES) model based on the energy storage characteristics of EVs. We then further integrated four types of EVs within the region to form EV clusters (EVCs) and constructed an EVC virtual energy storage (VES) model to obtain the dynamic charging and discharging boundaries of the EVCs. Next, based on the dispatch framework for the participation of renewable energy sources (RESs) and loads in the distribution network, we established a dual-objective optimization dispatch model, with the objectives of minimizing system operating costs and load fluctuations. We solved this model with NSGA-II and TOPSIS, which guided and optimized the charging and discharging of EVCs. Finally, the simulation results show that the system operating cost was reduced by 7.81%, and the peak-to-valley difference of the load was reduced by 3.83% after optimization. The system effectively achieves load peak shaving and valley filling, improving economic efficiency. [ABSTRACT FROM AUTHOR]

Pavement cracking is a primary cause of early damage in asphalt pavements, and fiber-reinforcement technology is an effective method for enhancing the anti-cracking performance of pavement mixtures. However, due to the multi-scale dispersed structure of pavement mixtures, it is challenging to address cracking and damage with a single fiber type or fibers of the same scale. To investigate the toughening mechanisms and damage behavior of hybrid-fiber-modified mixtures, we analyzed the fracture process and damage behavior of these mixtures using a combination of basalt fiber and calcium sulfate whisker hybrid fiber modification, along with semicircular bending tests. Additionally, digital imaging was employed to examine the fracture interface characteristics, revealing the toughening mechanisms at play. The results demonstrated that basalt fibers effectively broaden the toughness range of the modified mixture at the same temperature, reduce mixture stiffness, increase residual load at the same displacement, and improve crack resistance in the mixture matrix. While calcium sulfate whiskers enhanced the peak load of the mixture, their high stiffness modulus was found to be detrimental to the mixture's crack toughness. The fracture interface analysis indicated that the three-dimensionally distributed fibers form a spatial network within the mixture, restricting the relative movement of cement and aggregate, delaying crack propagation, and significantly improving the overall crack resistance of the mixture. [ABSTRACT FROM AUTHOR]

In this study, push-out tests were conducted on 20 specimens to explore the bond–slip performance of geopolymer concrete-filled steel tubes. The investigation focused on the effects of various design parameters such as length–diameter ratio, diameter–thickness ratio, concrete strength, and internal structural measures of the steel tube on the bond–slip performance. Analysis of the test phenomena, load–slip curves, and strain distribution curves of each specimen revealed insights into the shear strength calculation methods for welded stud structure and ring rib structure specimens. The results indicated a slight buckling deformation at the loading end of the steel tube in the structural specimen, while no significant deformation was observed in the non-structural specimen. The strain distribution along the height direction of the steel tube exhibited a triangular pattern, with the strain increasing gradually. Improvements in the interfacial bonding performance were noted with reductions in length–diameter ratio and diameter–thickness ratio of the steel tube, as well as increases in concrete strength. When the steel tube wall thickness t increases from 3.5 mm to 4.5 mm, the peak load of GC30-1 increases from 382.13 kN to 419.59 kN, an increase of 9.81%. After improving the concrete strength of GC30-1 and GC30-3 specimens, the peak load increases from 382.13 kN and 274.54 kN to 436.46 kN and 306.12 kN, respectively, an increase of 14.2% and 11.5%. Furthermore, the welding structure of the steel tube significantly enhanced the shear bearing capacity of the interface. The ratio of load calculation value to test value fell within the range of 0.917 to 1.098, indicating good agreement between the calculated and experimental values. These research results can provide reference for engineering applications of geopolymer concrete. [ABSTRACT FROM AUTHOR]

Based on the hysteretic tests of steel-reinforced reactive powder concrete (RPC) columns and reinforced RPC columns, the finite element numerical models of these two kinds of RPC columns were established by OpenSees (2016). The feasibility of the model was verified by comparing the results of tests and simulation. On this basis, the nonlinear analysis of seismic performance of cross-shaped-steel-reinforced RPC columns was carried out. The influences of different factors such as longitudinal reinforcement ratio, steel sectional resistance moment, RPC grade, steel strength and section form of shape steel on the hysteretic performance were investigated. Finally, the hysteretic model of cross-shaped-steel-reinforced RPC columns was established. The results showed that, compared with H-shaped-steel-reinforced RPC columns, the peak bearing capacity of cross-shaped-steel-reinforced RPC columns was increased by 21.2%, but the displacement ductility was obviously reduced. With the increase of slenderness ratio, the lateral stiffness and horizontal bearing capacity of cross-shaped steel RPC columns decreased rapidly. In addition, the peak load was improved with the increase of RPC strength, steel sectional resistance moment and longitudinal reinforcement ratio. The hysteretic model was consistent with the simulation results, which can effectively predict the hysteretic characteristics of cross-shaped-steel-reinforced RPC columns. The research results can provide a theoretical basis for the engineering design and application of cross-shaped-steel-reinforced RPC columns. [ABSTRACT FROM AUTHOR]

To meet the lightweight requirements of advanced composite materials, the ultralightweight three‐dimensional (3D) braided spacer composites were designed and manufactured by ultra‐high molecular weight polyethylene (UHMWPE). The key structural effects of core column distances and core column heights on the static bending, compression, and low‐velocity impact properties of the composites were further investigated. Results indicated that the mechanical properties of 3D braided spacer composites was closely depended on their structural parameters. The flexure and compression of 3D braided spacer composites decreased with increasing core column distance and core column height. W1/H1 specimen showed the optimal bending and compressive performance. The maximum flexural strength and flexural modulus were approximately 54.77 MPa and 4.95 GPa, respectively. The low‐velocity impact properties were further investigated where the stiffness, energy absorption, and impact resistance of the composite decreased with increasing core column distance. The peak load and energy absorption of the W1 specimen were 2.39 kN and 7.99 J, respectively. While the low‐velocity impact properties increased with increasing core column distance. The H3 specimen exhibited the greatest stiffness, impact resistance and energy absorption with peak loads and energy absorption of 2.81 kN and 8.49 J, respectively. In addition, the macro morphology and scanning electron microscopy (SEM)micrographs were examined to investigate the damage morphology and failure mechanism of the composites. The main failure modes were matrix cracking, interface debonding, fiber buckling, and dislocation, as well as tilting, and failure of the core columns. This work provides guidance for structural design and engineering application of 3D lightweight braided spacer composite. [ABSTRACT FROM AUTHOR]

This paper describes the 3rd Blind Simulation Competition (BSC) organized by the fib WP 2.4.1 which aims to assess the predictive performance of models based on the finite element method (FEM) for analysis and design of fiber reinforced concrete (FRC) structures submitted to loading and support conditions that promote punching failure mode. Fiber reinforcement is used in an attempt to eliminate conventional punching reinforcement and provide technical and economic advantages. The two tested real‐size prototypes represent a column‐slab interior region of an elevated steel‐fiber reinforced concrete (E‐SFRC) slab where anti‐progressive collapse reinforcement is disposed in the alignment of columns/piles. Despite a punching failure surface being formed in both experimentally tested prototypes at the rupture stage, fiber reinforcement was able to mobilize the yield capacity of the conventional flexural reinforcement, providing high deformation capacity, and ductility to the prototypes. The average post‐peak load‐carrying capacity of the tested prototypes at a deflection seven times higher than the deflection at yield initiation of the conventional reinforcement was still 90% of the average peak load. Regarding the BSC, a total of 26 proposals were received and involved 94 participants from 29 institutions and 17 countries, with 53.9% using smeared crack models (SCMs), 30.8% a concrete damage plasticity (CDP) model, 3.8% discrete crack models (DCMs) and 11.5% considered as “other models.” From these simulations it was verified, in average terms, that SCM assured the best predictive performance apart from the average strain in the SFRC and the maximum crack width which were better predicted by DCM. More accurate predictions were obtained by using in‐house software than by adopting commercial software. [ABSTRACT FROM AUTHOR]

Stationary hydrogen energy-based power plants generating electricity to supply high-powered plug-in electric vehicles (PEVs) have recently become popular in renewable energy-based power plants. Besides, in a PEV charging station, various types of powered charge devices can be established such as DC fast chargers or 3.7 kW, 7.4 kW, 11 kW, and 22 kW AC chargers. This paper introduces a demand-side management-oriented optimal charging strategy that includes two stages for PEVs in a hydrogen energy-based microgrid. The paper focuses on two stages to execute an optimal charging of PEVs in compliance with their users' requests and satisfaction and considering the power system loading. It is assumed that there are three types of chargers in the PEV charging station and the users. In the first stage randomly created requests are classified by an ensemble learning classifier method that performs higher performance classification by combining the results from multiple classifiers in a machine learning classification. The second stage schedules the PEVs according to the classification results and users' requests. To test the proposed system, first random requests are created then they are sent to the classifier, and the results of classifiers are scheduled in each other. The demand-side management-oriented charge scheduling and managing strategy which includes the proposed two stages has been compared with non-managed cases. Case study results reveal that the proposed approach provides 52.1% peak load reduction and 72.3% valley filling improvement by the SOS algorithm. The results highlight the advantages of the proposed system in terms of peak reduction and valley filling. [Display omitted] • A new intelligent decision-maker method is proposed for DSM in a microgrid. • Proposed method is developed for a stationary hydrogen energy-based power plant. • The optimal DSM of EVs is investigated with a hybrid ML method. • RUSBoost and SOS Algorithms-based Hybrid Intelligent Decision Maker is developed. • It provides 52.1% peak load reduction and 72.3% valley filling improvement. [ABSTRACT FROM AUTHOR]

Cracks in rock and concrete have a great adverse effect on the stability of engineering structures; however, there are few studies on X-shaped fissures which widely exist in rock and concrete structures. Based on this background, three-point bending fracture tests of SCB specimens containing X-shaped fissures are carried out. The momentum equations in the SPH method are improved, and the crack propagations of SCB specimens under three-point bending are simulated. The results show that cracks grow simply along the vertical direction in the sample with no X-shaped fissures, and the existence of an X-shaped fissure changes the crack growth path and final failure modes of the SCB samples. The crack propagation simulation results are consistent with the experimental results, which verifies the rationality of the improved SPH method. The load–displacement curves mainly present three typical stages: the initial compaction stage, linear elastic deformation stage, and failure stage. The peak load decreases first then increases with an increase in eccentricity. With an increase in X-shaped fissure length and decrease in X-shaped fissure angle, the peak load decreases. The damage counts remain at 0 at the initial loading stage, corresponding to the initial compaction stage and the linear elastic deformation stage, and increase sharply at the later loading stage, corresponding to the failure stage, which is consistent with the experimental results. The influence mechanisms of X-shaped fissures on the crack propagation paths are discussed; the existence of different X-shaped fissure morphologies aggravate the tensile stress concentration at specific positions, leading to different crack propagation modes in the experiments. The research results can provide a certain reference for understanding the failure mechanisms of engineering structures containing X-shaped fissures and promote the applications of the SPH method into the simulations of cross-fissure crack propagations. [ABSTRACT FROM AUTHOR]

To achieve the goals of high energy dissipation, a low initial peak, and small load fluctuation, a differentiated combination design of multitube combined structure was developed. Based on a combination of experiment, simulation, and theory, the influences of height and fold distribution on the peak-formation time sequence were investigated, and the combined method of two configurations in the multitube combination was determined. The results show that the initial peak and load fluctuation of the combined structure with variable tube heights and different fold distributions are reduced by 18.42% and 67.77%, respectively, compared with the multitube structure of the same configuration. [ABSTRACT FROM AUTHOR]

This study investigates the crashworthiness of biomimetic composite thin‐walled tubes under quasi‐static axial crushing, focusing on the effects of geometric structure and fiber orientation. The thin‐walled tubes, inspired by honeycomb structures, were manufactured using carbon fiber composites through multi‐cavity preform mold method. Quasi‐static crushing tests and CT scanning observation were conducted to characterize the mechanical response, crashworthiness mechanisms and energy absorption capacity of the thin‐walled tubes. Results demonstrated excellent energy absorption capacities across all configurations, with the C‐0/45 configuration achieving the highest specific energy absorption at 115.03 kJ/kg. The optimal crushing energy absorption process for thin‐walled tubes involves achieving high peak loads and maintaining high load levels. Sustaining high loads requires progressive and stable damage without the formation of extensive intermediate cracks between different plies (indicative of strong interlaminar shear strength). The structural integrity of the uncrushed sections must remain intact without significant damage during the crushing process. Fiber orientation parallel to the loading direction enhances peak load levels and interlaminar shear strength between plies, but may compromise circumferential stiffness and structural stability. The influence of geometric configuration is primarily manifested in the progressive and stable crushing phase, where the tube requires sufficient space to accumulate its own debris without causing damage to the uncrushed thin‐walled structure. Highlights: Structures and fiber orientation boost crashworthiness in biomimetic composite tubes.Biomimetic structures were produced using a multi‐cavity preform mold method.CT scans were conducted to characterize the energy absorption mechanisms.Composite tubes demonstrated excellent energy absorption capacity of 115 kJ/kg. [ABSTRACT FROM AUTHOR]

With the widespread application of distributed power sources in distribution networks, fault self-healing technology has become the key to ensuring the reliability of power systems. The micro-grid ensures system stability with a three-layer structure, where the designed method handles optimization problems, achieving faster global search and optimal solutions. Agents develop targeted recovery strategies by understanding network load, which are then executed by higher-level agents to ensure that the optimal recovery command is implemented by the system. According to the research results, during peak load, the system successfully outputted 7 kilowatts and met the load demand through battery discharge, demonstrating its self-healing ability. The output analysis of photovoltaic and wind turbines showed that the system reasonably scheduled within 24 h according to the changes in solar energy and wind power. Based on the quantum behavior particle swarm optimization algorithm, the system has achieved lower active power loss and greater power supply capacity. Although the number of switch operations has increased, the system performance has significantly improved, meeting the requirements for improving system economy and safety. It has promoting effects on the sustainable development of future power systems. [ABSTRACT FROM AUTHOR]

To address the issue of high auxiliary service costs caused by the grid connection of new energy generation, a dual layer optimization scheduling method for high penetration new energy power grids is proposed, taking into account the auxiliary service costs of grid connection. The correlation between the output fluctuations and load fluctuations of new energy generation is analyzed, and a calculation model for auxiliary service costs caused by grid connection of new energy generation is established. Taking into account the timescale division requirements for grid energy trading and auxiliary service market transactions, a new high penetration energy grid two-level optimization scheduling model is established. The upper level scheduling model aims to minimize the sum of grid energy procurement costs and auxiliary service costs caused by new energy generation and completes the optimization scheduling of the grid for several hours. The lower level scheduling model aims to closely follow the upper level scheduling plan for new energy power plants/groups. Optimization and scheduling of the power grid for tens of minutes is completed, taking into account the balanced allocation of wind and solar losses among various power plants within the new energy power plant group. The simulation results show that the method proposed in this paper can reduce the energy transaction costs and auxiliary service transaction costs of the power grid during low and peak load periods. [ABSTRACT FROM AUTHOR]

Numerous studies have reported the use of 3D-printed biocompatible intramedullary (IM) pins of various metals, alloys, and composite materials for a variety of orthopedic requirements in canines. One of the limitations of these IM pins is that they are non-resorbable, and required surgical procedures to be followed for their removal after performing the required function in the subject. Some studies have been reported on polyvinylidene fluoride (PVDF) composite-based smart IM pins that are partially absorbable. But hitherto less has been reported on the compressive properties of such 3D printed PVDF composite matrix. This study reports the compressive properties of 3D printed (by using fused filament fabrication (FFF) process) PVDF composite (90% PVDF-8% Hydroxyapatite (HAp)-2% Chitosan (CS) by wt.) for a partially absorbable implant for canines. The result suggested that the best setting for the FFF process are nozzle temperature (NT) 235°C, printing speed (PS) 60 mm/s, and raster angle (RA) 45° for the compressive properties (peak load (PL) 1321 N, break load (BL) 1188.9 N, strength at peak (SP) 10.83 MPa, and strength at break (SB) 9.75 MPa). Furthermore, analysis of the PVDF composite (at 10 N load, 300 s, and 60 r/min) outlined wear of 314 µm, friction force of 1.2 N, and a coefficient of friction of 0.14 was observed. The results are supported by the morphological analysis (based on scanning electron microscopy (SEM), % of porosity, grain size No.) of the fracture site. [ABSTRACT FROM AUTHOR]

OBJECTIVE: To assess the fatigue and load-to-failure mechanical characteristics of an intramedullary nail with a threaded interference design (TID) in comparison to a commercially available veterinary angle-stable nail with a Morse taper bolt design (I-Loc) of an equivalent size. METHODS: 10 single interlocking screw/bolt constructs of TID and I-Loc implants were assembled using steel pipe segments and placed through 50,000 cycles of simulated, physiologic axial or torsional loading. Entry torque, postfatigue extraction torque, and 10th, 25,000th, and 50,000th cycle torsional toggle were assessed. Each construct was then loaded to failure in the same respective direction as fatigue testing. Four complete constructs of each design were then assessed using a synthetic bone analog with a 50-mm central defect via nondestructive torsional and axial loading followed by axial load to failure. RESULTS: All constructs were angle stable at all time points and withstood fatigue loading. Median insertional torque, extraction torque-to-insertion torque ratio, and torsional yield load were 33%, 33%, and 72.5% lower, respectively, for the TID interlocking screws. No differences in torsional peak load, torsional stiffness, axial yield load, axial stiffness, or axial peak load were identified. No differences in complete construct angle stability, torsional stiffness, axial peak load, axial stiffness, or axial yield load were identified. CLINICAL RELEVANCE: The TID had an inferior torsional yield load when compared to I-Loc implants but generated angle stability and sustained simulated physiologic fatigue loading. The TID may be a suitable mechanism for generating angle stability in interlocking nails. [ABSTRACT FROM AUTHOR]

This paper presents experimental studies to investigate the compressive and shear behaviors of cold-formed thin-walled steel-foam concrete composite walls. Three compressive walls and three shear walls were tested. The failure mode and load-displacement curve of the specimen were obtained from the compressive experiment. The compressive wall infilled with foam concrete mainly experienced distortion buckling of the end stud and local crushing failure of the concrete. The stud openings had a limited effect on the compressive bearing capacity of the composite wall. The failure mode and load-deformation curve were obtained in shear tests. The ductility index, shear stiffness, yield load, peak load, energy dissipation, and stiffness degradation were analyzed. The shear composite wall filled with foam concrete mainly occurred concrete crushing failure, local or distortional buckling failure of the end stud, and cracking failure of the calcium silicate board. The shear stiffness, shear capacity, ductility, and energy dissipation of the composite wall could be significantly improved after filling with foam concrete. [ABSTRACT FROM AUTHOR]

This study investigates soil–steel composite structures, emphasizing the role of stiffening ribs and geotextile reinforcement through comprehensive numerical modeling. This study presents a two-dimensional finite element analysis (FEA) and compares the influence of stiffening rib and geotextile on the ultimate bearing capacity of the soil–steel composite structures. The results of this study demonstrate a significant enhancement in load capacity. Specifically, a notable 47% improvement was observed with a stiffening rib, and a 26% increase was noted with the use of a single layer of geotextile. Under peak load, the vertical displacement at the crown exceeds the permissible standard for all models except for one model, while bending moments reach their limits, marking a failure mode of composite system considered. Structures with stiffened ribs reach their load capacity due to the creation of a plastic hinge around the shoulder and haunch of the shell. On the other hand, in structures without stiffening ribs, the crown and haunch section of the shell becomes fully plastic under peak load. The maximum axial thrust is shown in geotextile-reinforced structure, reaching 78% of the shell maximum capacity due to compression. Eventually, stiffening rib substantially improves overall load-bearing capacity of the soil–steel composite structures, and geotextile placement in the upper part of the backfill reduces shell deflection due to bending. [ABSTRACT FROM AUTHOR]

The flexural behavior of hybrid timber–steel encased beams comprising coniferous radiata pine (Pinus radiata) (MGP10) and Douglas fir (Pseudotsuga menziesii) (F8) timber lamellae with bonded-in steel bars is studied. The effect of cross-section depth, steel bar size, timber species/grade, and steel bar arrangements (only bottom and top-and-bottom) on the hybrid beams' stiffness, failure mode, ductility, and load-carrying capacity were investigated. The flexural capacity and stiffness of the doubly (top-and-bottom) reinforced beams are increased by 127% and 71%, respectively. However, in the singly (bottom) reinforced beams, the flexural capacity and stiffness are increased only by 41% and 25%, respectively, highlighting the important role of the compressive bars. The failure of all beams was associated with tensile flexural failure of timber, but the steel bars improved the ductility of the beams. The maximum coefficient of variation of the peak load in hybrid beams (CoV=14.3%) is lower than that of the bare timber beams (CoV=21.7%). Two analytical models were developed based on a linear and a bilinear stress–strain relationship for timber. The analytically predicted peak load and stiffness agree well (less than 13% and 12% difference) with the experimental results. [ABSTRACT FROM AUTHOR]