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The Tarcha coal deposit, located beneath the Omo trachyte flows in the Omo‐Gibe River basin of southern Ethiopia, is actively mined using open‐pit methods for energy resources. However, these mines face significant slope instability issues. This study aims to assess and enhance the stability of the selected open‐pit coal mine quarries through field and laboratory analyses, supported by the limit equilibrium method (LEM) and the finite element method (FEM). Fieldwork involved detailed measurements of slope geometry and orientation, in situ rock testing, and soil and rock sampling for laboratory analysis. Results indicated that the rock quality designation (RQD) of the rocks ranged from 22 to 57.5, indicating rock quality from very poor to fair. Schmidt hammer tests revealed uniaxial compressive strength (UCS) values between 14.79 and 29.31 MPa. Soil analysis classified the soils as sand with low to high plasticity (8.89% to 31.86%) and a liquid limit range of 21% to 62.63%. Stability analyses using LEM and FEM on two critical slopes (MS‐1 and MS‐2) under saturated, unloading, and loading conditions indicated instability. However, geometric adjustments, such as reducing slope angle, decreasing slope height, and implementing benching, were found to significantly improve slope stability. [ABSTRACT FROM AUTHOR]

The dynamics of wind turbine (WT) behavior and the identification of factors influencing its performance are both highly complex and challenging. Additionally, component damage, along with sensor and actuator failures, can lead to system faults that significantly reduce performance. Understanding these impacts provides control system designers with valuable insights to develop strategies for mitigating faults and enhancing WT performance. This study presents a novel evaluation of rotor fault effects on output power and measured variables in WTs using Monte Carlo simulation and sensitivity analysis. Through comprehensive simulation and numerical analysis, the faults with the greatest impact on WT performance are identified. The results of this research not only provide a better understanding of the WT performance during faults but also identify the significant effects of these faults on the performance of wind turbines and specifically identify and prioritize the main faults. These results are instrumental in improving control strategies, developing preventive maintenance programs, and offering practical solutions to reduce operational costs and extend the equipment's useful life. [ABSTRACT FROM AUTHOR]

Open‐type Sabo dam captures the advantage of solids mitigating the potential energy of fluids, but the disadvantage is that a small amount of debris flow passes through the dam, the reason for this comes from the grid size of the dam, the inclination angle of the dam, the stone size among the debris flow, etc. This study aims to investigate the influence of the inclination angle on the capture performance of the open‐type Sabo dam. A model experiment is conducted based on the centrifuge machine. Three open‐type Sabo dam models reflecting different inclination angles of 0° (vertical form), 20°, and 40° are used to capture the debris flow. The concentration of the large particle (CLP) for the debris flow configuration is set to 20% and 33%, respectively. The experimental results indicate that the open‐type Sabo dam with 0° inclination angle has the best capture rate, 93%–94%. An increase in inclination decreases the capture rate for debris flows. A 40° inclination angle decreases the capture rate by 2%–8%, and this decrease is exacerbated by an increase in CLP of the debris flow. Additionally, the smoothed‐particle hydrodynamics–distributed contact distinct element method (SPH–DCDEM) has a good reproduction for the experimental result of the capture rate, with an error of 12%–25%. [ABSTRACT FROM AUTHOR]

This paper focuses on the finite‐time synchronization issue for reaction‐diffusion competitive neural networks (RCNNs) with different time scales and time‐varying delays. To reduce the waste of network resources, a periodically intermittent control strategy is presented based on two time scales (short and long memory) and time‐varying delay. By constructing the Lyapunov–Krasovskii functional, with the help of Lyapunov stability theory and auxiliary inequality technique, the finite‐time synchronization can be guaranteed and the settling time is exactly estimated. Finally, an exhaustive numerical analysis is presented to illustrate the effectiveness of the controller and the correctness of theoretical results. [ABSTRACT FROM AUTHOR]

Operational modal analysis is a robust and practical approach to structural health monitoring which assumes white noise as input. Therefore, the accuracy of this method can be compromised when dealing with colored unknown excitations, in which, for example, harmonic loads induced by the operation of mechanical equipment, may affect the modal parameter estimation. This study aims to address the challenge of identifying both natural and forcing frequencies of a complex building by exploiting the potentiality of both the spectral kurtosis analysis and stochastic subspace identification technique. The first one is based on the evaluation of a statistical quantity characterized by low values when data are stationary and Gaussian and high values when specific frequencies and nonstationarity are present in the signals. It allows the detection of harmonics, transients, and repetitive impulses in the frequency domain. Its combined use with the stochastic subspace identification technique enables us to effectively identify and separate harmonic‐induced vibrations from structural response to ambient white noise. This approach can lead to a more accurate modal parameter estimation that has been investigated in this work through numerical and experimental analyses carried out on the Cardinal Massaia hospital building in Asti, Italy. An experimental daily dynamic campaign has been carried out to acquire accelerations in operational conditions including disturbances due to machinery like elevators and air conditioners. The combined use of kurtosis analysis and stochastic subspace identification techniques has been used to process a large dataset of noisy measurements acquired in operational conditions. Five different measurement setups have been implemented, each one composed of 14 sensors. Notwithstanding the complexity of the case study under investigation for both the structural configuration and difficulties in the experimental data acquisition, this approach allowed to distinguish natural from forcing frequencies, highlighting its accuracy and robustness. [ABSTRACT FROM AUTHOR]

This research paper focuses on investigating the phenomenon of entropy generation, specifically within the context of blood flow. Blood is modeled as a three‐layered liquid model, with micropolar and Newtonian fluids occupying the center and periphery sections of the tube, respectively. A narrow glycocalyx layer adjacent to the wall is regarded as indicating a permeable area caused by the accumulation of carbohydrates and fibrous tissues within the tube wall. Further, the walls of the cylinder are taken as permeable. The objectives of this study include understanding the mechanisms and factors contributing to entropy generation in blood patterns, exploring the relationship between entropy generation and flow characteristics, and analyzing the impact of entropy generation on the overall energy efficiency of the system. The transformation of ordinary differential equations (ODEs) from partial differential equations (PDEs) can be accomplished by employing a similarity approach that combines shooting methods with the inculcation of the RK‐4 method. This integrated technique facilitates the transformation process effectively. Then, MATLAB software is used to plot graphs for accuracy purposes. Under various physical limitations, the comparison study demonstrates that trihybrid nanoliquids exhibit ultrahigh thermal efficiency compared to ordinary nanoliquids, and incorporating these nanofluids enhances entropy generation, temperature, and Bejan profiles, improving thermal conductivity and energy transfer. This integration ensures sustained performance over time, benefiting from carefully selected nanoparticles for stability optimization. As a result, these fluids are extremely useful for industrial applications, particularly filtration and ultrahigh heat. [ABSTRACT FROM AUTHOR]

Hybrid on‐load tap changers (OLTCs) are attractive solutions for the smooth change in voltage without current interruption in the converter transformer. This paper proposes a systematic topology derivation method of hybrid OLTC. To begin with, the topology derivation principle of OLTC is studied according to graph theory and equivalent electrical network theory, and the basic structure of OLTCs is constructed. Based on the topology derivation and optimization method, some hybrid OLTC topologies are derived. Particularly, a new hybrid star‐type parallel three‐switch OLTC topology with independent intellectual property rights is investigated in detail. Then, the optimal timing control is designed to reduce the time of current flow and shorten the overall switching time. Circuit simulation results show that arc‐free and reliable switching can be realized in the new topology. In addition, the losses and the heat generated during the switching process are calculated, and the impact of the phase between the stage voltage and system current on the loss and electrical stress is studied. Furthermore, the comparison between the proposed topology and other topologies is carried out to show the advantages of the proposed topology. Finally, Saber circuit simulation will be carried out to verify the theoretical and numerical analysis results. [ABSTRACT FROM AUTHOR]

The utilization of numerical analytic techniques has become essential in evaluating the environmental consequences of excavation in foundation pits. The careful selection of suitable soil constitutive models has significant importance in this regard. The Hardening Soil (HS) model has become widely utilized in the numerical analysis of foundation pits among the several models considered. The essence of a constitutive model is in the identification and determination of its calculation parameters. The stress–strain curve is derived by conducting triaxial testing, utilizing the inherent properties of the particle swarm optimization (PSO) technique. The objective function entails quantifying the disparity between stress–strain curves obtained from various parameters and experimental curves while iteratively searching for five crucial parameters of soil‐hardening models: effective internal friction angle φ, effective cohesion, failure ratio Rf, stiffness level‐dependent power exponent, and standard triaxial‐drained test secant stiffness E50ref. The objective of this research is to create a computational software utilizing the Python programming language to execute PSO with the purpose of determining sets of five fundamental soil constitutive parameters. This research employs optimized parameters acquired from PSO to construct a numerical model for foundation pits and performs numerical computations. Accurate findings may be reached by comparing the measured deformation in the numerical simulation with that seen in actual foundation pits. The results demonstrate a high degree of consistency between the experimental curves and the five parameter combinations obtained through the PSO algorithm, with an error rate not exceeding 8.2%. Moreover, the optimized curves exhibit closer alignment with theoretical expectations. The settlement values calculated using a numerical model based on optimized parameters show only a 6.12% deviation from actual measurements while closely following the trend of the observed curve. This outcome has the potential to greatly alleviate the burden of conducting indoor tests and holds considerable practical value in engineering applications. The observable optimization impact of PSO also serves as evidence of its viability in improving soil constitutive parameters, providing new perspectives and sources of information for future progress in this domain. [ABSTRACT FROM AUTHOR]

Many existing buildings fail to meet the requirements of current earthquake resistance codes. Therefore, it is necessary to strengthen and/or upgrade such buildings. Strengthening and/or upgrading include adding new floors, parts, elements, etc. Modern codes usually do not reflect upgrading of existing buildings. These buildings may be damaged and require maintenance and repairs, which may change the original material and structural properties. Design of such buildings is based on dominant vibration periods obtained by empirical dependences according to the building codes or from dynamic numerical analysis using available software. In both cases, the results usually do not consider the present state of the structure, influence of nonstructural elements, and possible differences in material properties in various elements of the building due to construction problems, concrete creep, etc. Such evaluation can be done just based on dynamic analysis, experimental and numeric, whereas the first one is essential. Therefore, the present research is aimed at numerical and experimental investigation of an existing real multistory residential reinforced concrete building before its strengthening and/or upgrading according to the requirements of modern seismic codes. The present study is a first stage of the research. It is focused on obtaining the dynamic parameters of the building before its strengthening and upgrading. Experimental values of natural vibration periods and damping ratios are compared with those obtained numerically. Following these values, the design spectrum of the seismic code is updated and the building is designed using this updated spectrum. The findings of this study form a basis for the second research stage that will be aimed at monitoring and analyzing of this building at each stage of its strengthening and upgrading. This approach iaimed at improving the available techniques for strengthening and upgrading the building. It will also be the basis for further research in this direction. [ABSTRACT FROM AUTHOR]

This research uses numerical simulations to analyze the vortices and velocities inside gas‐liquid separators of various shapes in order to investigate their separation. The gas‐liquid flow inside the separator is simulated using the Eulerian and RNG k‐ε models, which also provide iso‐vorticity surfaces based on the Ω approach. The findings indicate that more powerful turbulence effects are caused by larger vortex surfaces, such as mixed structure (CS) separators, more vortex volume, and a substantially higher density of vortex nuclei. The liquid film extraction structure (LFES) separator has a larger tangential velocity at high cross sections, which is favorable for reducing film build‐up. Because of its high positive radial velocity, the filter structure (FS) separator helps to lessen droplet carryover. At high cross sections, the tangential velocity of the LFES separator is higher, which is advantageous for lowering droplet carryover. The pressure and phase volume fraction distributions are consistent with the results of the vorticity and velocity analyses. When comparing the liquid separation efficiencies of separators with various designs, the FS separator outperforms the LFES separator, with the CS separator having the best efficiency. The study's conclusions offer guidance for the separator's structural modifications and industrial uses. [ABSTRACT FROM AUTHOR]

Nitrogen oxides (NOx), classified as an indirect greenhouse gas (GHG), are increasing in demand for reduction as emission regulations are expanded not only in internal combustion engines but also throughout the industry. Nitrogen atoms are dissociated at relatively low temperature and can be easily converted to NOx by radicals and intermediates, so the reaction pathway is complex and changes in a short time. Therefore, numerical analysis methods should be used to simulate combustion phenomena and analyze chemical reactions, emphasizing the importance of the reaction mechanism, which includes reaction constants and reaction pathways. In this study, the laminar premixed flame was simulated using a numerical analysis method, and the NOx formation characteristics were identified according to the analysis variables using a reaction mechanism. The study was carried out using GRI 3.0, Okafor, and Konnov 0.5, which includes the combustion reaction of methane, as the variables used were equivalence ratio and inlet temperature. As a result, it was confirmed that Konnov 0.5 generates less NOx compared to GRI 3.0 and Okafor. Upon analyzing the reaction contribution, it became apparent that the hydrocarbon chain and chain‐branching reaction and the third‐body efficiency coefficient contribute to Konnov 0.5's NOx generation. The results in one and two dimensions showed similar trends. It is expected that similar results will be obtained for higher‐dimensional systems with complex physical phenomena. [ABSTRACT FROM AUTHOR]

A second-order numerical method for two-sided tempered fractional convection-diffusion equations is studied in this paper, both convection term and diffusion term are approximated by the tempered weighted and shifted Grünwald difference operators, the first time partial derivative is discretized by the Crank–Nicolson method, and then a class of second-order numerical schemes is derived. By means of matrix method, numerical schemes are proved to be unconditionally stable and convergent with order O τ 2 + h 2 . The validity of the proposed numerical scheme is verified by numerical experiments. [ABSTRACT FROM AUTHOR]

This study presents a detailed numerical analysis of nonlinear aeroelastic behavior in a two degree of freedom (DOF) model, focusing on plunge and pitch motions and employing the continuation method (CM) with an adaptive step size control algorithm. The research incorporates free-play nonlinearity at the plunge hinge, a common structural nonlinearity in aeronautics that can induce detrimental limit cycle oscillations (LCOs) during flight. By examining three scenarios—linear response, unhindered plunge motion, and nonlinear stiffness behavior—the study assesses the effects of free play on flutter and LCO phenomena, including discontinuity-induced bifurcations like grazing bifurcation. Additionally, the study explores parameter variation for nonlinear flutter analysis, revealing the dynamics of grazing bifurcation and its impact on LCO behavior. The research also demonstrates the method's superior accuracy in flutter speed estimation and mode-switching identification, despite higher computational demands. The findings underscore the diminishing influence of nonlinear free-play behavior on LCO amplitude, providing insights with significant implications for aeroelastic design and aircraft safety. [ABSTRACT FROM AUTHOR]

Retaining wall is essential for stopes mining in two steps, for it can prevent the instability and collapse of backfill. In this study, taking the retaining wall of backfilled stope as the research object, a stability analysis method of retaining wall based on the close coupling of catastrophe theory and numerical analysis was proposed. First, by extracting the unit failure rate of the retaining wall from the numerical simulation results and fitting it with the mining depth, the functional expression between them was established. Second, the function relation was transformed into the normal form according to catastrophe theory, and the instability criterion of retaining wall was deduced. Furthermore, an effort was made to analyze the changing law of the state of retaining wall and calculate the critical span of stope, under different thickness conditions. On this basis, the application test of retaining wall was carried out by using this method. The results show that with the thickness decreasing, the values of splitting variables a and b show a reverse trend, which leads to the discriminant of instability criterion decreasing and turning from positive to negative, resulting in the collapse. Meanwhile, in order to ensure the stability, the wider the span of the stope, the thicker the retaining wall is required, and conversely, the thicker the retaining wall, the higher the adaptability to the span of stope. In addition, it can be found from the application test that instability was bound to occur with a thickness of 3 m, but the retaining wall with a thickness of 4 m maintained stable, which tended to be consistent with the analysis. Therefore, the stability analysis method proposed in this study provides a way to accurately evaluate the stability of the retaining wall and calculate the critical thickness of that, and its application value is expected to be further explored. [ABSTRACT FROM AUTHOR]

The hydraulic circuit in hydraulic mechanisms may be the cause of several vibration anomalies. Flexible pipes, in particular, commonly used in test rigs, may be the source of vibration issues due to their relatively low natural frequencies altering the pump noise, vibration, and harshness (NVH) performance. The purpose of this study is to detail a methodology based on lumped parameter modeling and experiments to analyze the circuit NVH behavior. An experimental study is carried out on two pump designs to determine the outlet pressure fluctuation of various test rig configurations. Numerical simulations are also performed to simulate the actual behavior of the hydraulic system considering these different test configurations. The tests are carried out at a chosen frequency range with a hydraulic circuit configuration representing realistic layouts. In these situations, the hydraulic circuit layout can be the source of NVH anomalies. Realistic design solutions are proposed to modify the test rig NVH behavior in order to achieve a flat response throughout the desired working range. [ABSTRACT FROM AUTHOR]

In this study, a heterojunction (P+ a-SiC/i intrinsic/n-Si) solar cell has been examined and characterized using the Analysis of Microelectronics and Photonic Structures (AMPS-1D) simulator. In this heterojunction solar cell, an intrinsic layer is imposed to enhance the efficiency and performance. The optimum efficiency of 36.52% (Voc = 1.714 V, Jsc = 27.006 mA/cm2, and FF = 0.789) has been achieved with this intrinsic layer. It has also been observed the solar cell without intrinsic layer. In this case, the maximum efficiency of 2.378% has been observed which is very poor. The heterojunction solar cell also has been investigated with electron blocking layer (EBL) and defect layer. In this case, the simulation result shows the lower efficiency (34.357%) than the previous. This research paper introduces an optimized model of a heterojunction solar cell enhanced with an intrinsic layer to improve efficiency. The proposed design shows significant promise in its theoretical framework. Looking forward, the design could be realized in laboratory settings and has the potential to be scaled up for broader applications. [ABSTRACT FROM AUTHOR]

In this article, a subgrid-sparse-grad-div method for incompressible flow problem was proposed, which is a combination of the subgrid stabilization method and the recently proposed sparse-grad-div method. The method maintains the advantage of both methods: (i) It is robust for solving incompressible flow problem with dominance of the convection, especially when the viscosity is too small. (ii) It can keep mass conservation. Therefore, the method is very efficient for solving incompressible flow. Moreover, based on the Crank–Nicolson extrapolated scheme for temporal discretization, and mixed finite element in spatial discretization, we derive the unconditional stability and optimal convergence of the method. Finally, numerical experiments are proposed to validate the theoretical predictions and demonstrate the efficiency of the method on a test problem for incompressible flow. [ABSTRACT FROM AUTHOR]

In recent years, to effectively mitigate the issue of urban traffic congestion, tunnels have become widely used new type of road. However, when the soil layer is excavated and disturbed, the resulting vibration affects the safety of the buildings above it, especially for ancient buildings that are very sensitive to vibrations. Taking the White Tower in Hangzhou as an example, in this paper, the vibration response propagation of large-diameter shield tunnel excavation to adjacent ancient towers is studied through field measurements. The vibration response of the unexcavated south line tunnel is predicted by using 3D numerical analysis software, and the optimal construction parameters are obtained. The study found that the frequency domain component of the White Tower bedrock vibration caused by shield tunneling is mainly 5–20 Hz, and the vibration response attenuates significantly beyond 40 m. Further, reducing the propulsive force can reduce the vibration response of the White Tower; therefore, controlling the propulsion and reducing the tunneling velocity can reduce the vibration response. [ABSTRACT FROM AUTHOR]

Early tied-arch bridges cannot satisfy the current traffic load demand due to their load grades and maintenance levels. Also, these tied-arch bridges have accumulated structural damage with increasingly prominent safety risks. In order to accurately evaluate the characteristics of tied-arch bridges' structural-influenced lines and identify damage of their arch ribs and suspenders, two analytical solutions are derived and established in this paper for the thrust-influenced lines of parabola and catenary two-hinged arches with a tie beam. A new method and an index for identifying damage of arch ribs and suspenders of tied-arch bridges are proposed. The results of numerical simulation in this paper verified that the proposed analytical solution has good analytical accuracy in practice on those two-hinged nonflat arches. With the use of equivalent thrust-influenced line difference curvature, the effectiveness of damage identification and the verification method were verified on the tie beam, suspender, and arch rib of plane tie arch structure as well as the suspender and arch rib of tied-arch bridges in this research. Furthermore, combining with grey relation analysis, the noise immunity of the proposed index method can be verified. Also, thrust-influenced line recognition based on VMD (variational mode decomposition) is introduced, and a practical process of bridge health assessment based on the quasistatic-influenced line loading of three-axle heavy vehicles is established. Theoretical analysis and numerical verification show that the calculated error of the analytic solution of two-hinged arches with a rise-span ratio greater than 1/8 is less than 9.57%, and the error decreases with the increase of the rise-span ratio. Therefore, it can be applied to the calculation and analysis of tied-arch bridges with a rise-span ratio range between 1/4 and 1/5. With the equivalent thrust-influenced line index proposed in this paper, the damage of suspenders and arch ribs of tied-arch bridges can be accurately located. It has been found that the proposed method is more effective to identify the damage of suspenders than the damage of arch ribs does, showing good noise immunity. In summary, this research has provided theoretical support for arch bridge design and evaluation. Combining with existing bridge-monitoring methods, the new bridge damage identification method proposed in this paper has the prospect of realizing the normal health status assessment of existing tied-arch bridges. [ABSTRACT FROM AUTHOR]

Modal parameters are used as safety assessment indicators for evaluating the structural integrity of buildings in various ways. In particular, the modal damping ratio plays a crucial role in accurately predicting the serviceability and safety of buildings, starting from the initial design stage. However, the identification results of the modal damping ratio can become unstable due to measurement time, initial configuration conditions used in the analysis, and nonstationary responses included in the structural response. To address the instability issue, this study proposes a long short-term memory-based frequency domain decomposition (FDD-LSTM) method. The FDD-LSTM method utilizes the acceleration response of the building as input data and the modal damping ratio obtained from the FDD method as output data, constructing an LSTM network model for the relationship between the acceleration response and modal damping ratio. The FDD-LSTM method exhibited a discrepancy of less than 0.02% compared to the reference value of the modal damping ratio obtained through free vibration response. Furthermore, when applied to data acquired from an actual building, the method demonstrated a variance of approximately 5%. The proposed FDD-LSTM method is validated for stability performance using a three-degree-of-freedom numerical analysis model, a 3-story steel frame structure model, and a 117-story high-rise building. The FDD-LSTM method, trained on a large dataset, enables generalized estimation and addresses instability issues related to modal damping ratio. [ABSTRACT FROM AUTHOR]

Natural convection in cavity plays a significant role in energy-related field, including the indoor heat transfer analysis in greenhouse with integrated PV roof. In this study, mathematical model is established for two-dimensional heat transfer analysis in greenhouse air cavity, with numerical simulation through computational fluid dynamics (CFD). Main natural convection impact factors, such as system configuration parameters (tilting angle and PV panel unit number) and fluid thermal–physical properties, are investigated with indoor temperature distribution and streamline comparison by finite-volume method (FVD). Preliminary results show that with rising Rayleigh number (Ra), natural convection is enhanced with growing Nusselt number (Nu). Moreover, panel slope tilting angle (θ) highly determines inside heat transfer subregions in terms of the vertical temperature gradient declines with rising θ, improving the temperature distribution uniformity inside. The solar greenhouse example illustrates that with the increasing numbers of panel group numbers (n), the air temperature gradient differences decrease, improving the temperature distribution uniformity inside, which is preferable to built environment accurate control for greenhouse in the practical engineering. This work can provide modeling method support and reference for natural heat convection applications. [ABSTRACT FROM AUTHOR]

Based on the analytical method of formation deformation caused by tunnel excavation proposed by Verruijt and Sagaseta, combined with the basic principles of soil mechanics and elastic mechanics, a method for determining the pending parameters required in the analysis process is proposed. This method does not require the actual measurement of deformation values in the field, and the required parameters can be determined from geological data, so as to obtain the deformation values of any points of the whole stratum. According to engineering examples, when the pending parameters are obtained by this method, the difference between the resolved value of maximum surface settlement and the measured value can be controlled within 5.0%, and the analytical results can splendidly reflect the formation deformation law caused by tunnel excavation. Further combined with the analysis of the numerical simulation results, the proposed approximation method has certain shortcomings and deficiencies, mainly in the lack of lateral constraints on the displacement. When the measured data in the field are insufficient, this method can be used to estimate the deformation, and the analysis results are slightly larger than the measured values, which is safer. [ABSTRACT FROM AUTHOR]

Introduction. Despite the availability of effective biologic therapies for psoriasis, there is no gold-standard treatment for nonpustular palmoplantar psoriasis (ppPsO). Methods. G-PLUS, a phase IIIb, double-blind, placebo-controlled, multicentre clinical trial, randomised adults with moderate-to-severe nonpustular ppPsO and limited plaque psoriasis (Psoriasis Area and Severity Index (PASI) ≥3 but <10) to guselkumab (an interleukin-23p19 blocker) or placebo. Placebo participants were crossed over to receive guselkumab at week (Wk) 16. The primary efficacy endpoint was the proportion of participants achieving palmoplantar PASI (ppPASI) 75 response at Wk16; clinical, biomarker, and quality-of-life endpoints were assessed through Wk48 and safety through Wk56. Results. At Wk16, ppPASI75 response was achieved by 35.9% of the guselkumab participants compared with 28.2% in the placebo group, resulting in a 7.7% difference in response rates (95% confidence interval: −11.5 and 24.7), which was not statistically significant (p = 0.533). More pronounced numerical improvements favouring guselkumab were observed for more stringent efficacy endpoints, such as Wk16 palmoplantar Investigator's Global Assessment (ppIGA) 0/1 response (guselkumab 34.6% vs. placebo 15.4%). Through Wk48, further improvements were observed in ppPASI75 response (55.1% and 64.1%) and ppIGA 0/1 response (42.3% and 48.7%) for the guselkumab and placebo-crossover groups, respectively. Dermatology Life Quality Index responses showed comparable trends at both timepoints. Safety and pharmacodynamic findings were consistent with the established profile for guselkumab. Serum biomarker levels were significantly reduced with guselkumab and correlated with the baseline PASI score but not the ppPASI score. Conclusion. Although the primary endpoint was not met, analysis of stringent secondary endpoints and post hoc analyses showed numerical improvements favouring guselkumab at Wk16. There were no new safety signals. Further studies are warranted to better understand the impact of guselkumab treatment in patients with ppPsO. This trial is registered with NCT03998683. [ABSTRACT FROM AUTHOR]

The aim of this research work is to obtain the numerical solution of Fisher's equation using the radial basis function (RBF) with pseudospectral method (RBF-PS). The two optimization techniques, namely, particle swarm optimization (PSO) and artificial bee colony (ABC), have been compared for the numerical results in terms of errors, which are employed to find the shape parameter of the RBF. Two problems of Fisher's equation are presented to test the accuracy of the method, and the obtained numerical results are compared to verify the effectiveness of this novel approach. The calculation of the error norms leads to the conclusion that the performance of PSO is better than the ABC algorithm to minimize the error for the shape parameter in a given range. [ABSTRACT FROM AUTHOR]

To assess the applicability of the tension estimation method using local vibration measurements in a thorough manner, this research work is devoted to systematically investigate the appropriate covering ranges of measurements for different cables. Four cables of three cable-stayed bridges are deliberately chosen to cover a wide range of the cable slenderness parameter. Numerical analyses with finite element models and field validations with real measurements are conducted for these stay cables to demonstrate that the covering range of local measurements can be undoubtedly reduced with the increase of cable slenderness. For a relatively short cable with the slenderness parameter at the order of 4000, the adoption of 1/3 coverage is sufficient to keep a high-level accuracy with at most 1% of error. Besides, 1/4, 1/6, and 1/7 coverages are found adequate to maintain the same level of accuracy for longer cables with the slenderness parameter at the orders of 30000, 55000, and 80000, respectively. With the solid validations presented in the current study, the covering range of the cable for this simplified method employing local vibration measurements can be confidently reduced to greatly alleviate the expense and hard work of sensor installation near the high end. [ABSTRACT FROM AUTHOR]

The performance of structural composites during loading has always been a concern for the designers and construction industry since the reinforced concrete structure was discovered. In this study, lateral load–displacement behavior of beam–column joints wrapped with aramid fiber is evaluated using both experimental and numerical analysis subjected to torsional moment (beam-eccentric loading). Three categories of reinforcement concepts are adopted for the preparation of the beam–column joints, where members are wrapped with aramid fiber at the joints, and others are not fortified with aramid fibers. Prior to testing, the structural composites are cured for maximum 28 days into water. The beam–column joints are subjected to lateral load at a point near the column end of the beam–column connection, and the corresponding deflections are measured until the member fails. Based on the test results, ductility and energy absorption capacity are evaluated. The findings of the numerical investigation of beam–column joint show there is not much variation in the experimental and numerical analysis; it is clearly found that aramid fiber wrapping provided large rigidity in the joint, and it is also prolonged the final failure of the joints. This study shows that in addition to the conventional reinforcement, providing the hanger reinforcement and the diagonal reinforcement improves the rigidity of the beam–column joints during severe loadings, as this study described. [ABSTRACT FROM AUTHOR]

Considering that the effect of solar radiation on the super-high arch dam temperature field remains poorly studied, the calculation accuracy of dam temperature deformation is unable to be guaranteed accordingly. To address the issue, the solar radiation effect is adequately taken into consideration by proposing a practical calculation method based on the ray-tracing algorithm, the precomputation algorithm, and the ASHRAE clear sky model in this paper. With the aid of the ASHRAE clear sky model, the solar radiation received by the super-high arch dam and reservoir water is calculated. The shading effects are calculated by means of the ray-tracing algorithm, and the precomputation technology is introduced to further enhance the computational efficiency. Finally, to guarantee the authenticity of the calculation results, the dam thermodynamic parameters are inversed by employing the hybrid genetic algorithm. Based on the application in a real-life case, we concluded that around one third of the entire dam radial temperature deformation was attributable to solar radiation during continuous sunny days. The analysis results signify a critical role for taking account of the solar radiation in dam deformation calculation. Furthermore, the practicability and utilization prospect of the proposed method was verified. [ABSTRACT FROM AUTHOR]

The search for efficient higher order methods is a constant goal in numerical analysis. In this paper, a higher order two-step hybrid block method is presented to directly solve second-order initial value problems in ordinary differential equations. In addition to the higher order, the proposed method has been formulated in variable step-size mode to extract its best performance. Comparisons with other methods in the literature show the good accuracy it can provide. Theoretical aspects such as linear stability and convergence analysis are also discussed. [ABSTRACT FROM AUTHOR]

In order to effectively improve the impact resistance performance of the roadway anti-impact hydraulic support and reduce the loss caused by rock burst to a certain extent, a torsion plate energy-absorbing member was designed for using with the hydraulic column. By using theoretical analysis and numerical simulation methods and combining them with the parameters of the energy-absorbing characteristics evaluation index, single-factor tests were designed. Under the premise of constant impact velocity, the influence law of torsion angle, plate thickness, and fillet radius of the pressure plate on the energy-absorbing and anti-impact characteristics of energy-absorbing members were analysed. The results show that the deformation process and resistance trend of the torsion plate correspond to energy absorption. The resistance stability is high in the reaction force platform stage, and the energy increases linearly. With the increase of the torsion angle, the mean value of the reaction force increases, the fluctuation of the reaction force platform stage becomes more obvious, the specific energy absorption increases linearly, and the standard deviation reaches the minimum at 480°. Both the tensile length and the length of the reaction force platform stage increase continuously. With the increase of the plate thickness, the flatness of the torsion plate shows a trend of bad-good-bad, the mean value of the reaction force gradually increases, the specific energy absorption grows faster and then slower, and the tensile length and the length of the reaction force platform stage increase accordingly. With the increase of the fillet radius, the flatness of the torsion plate is better and the reaction force has a small improvement. The fluctuation of reaction force is most significant when the fillet radius is 2 mm, and the energy-absorbing member has the largest swing. The specific energy absorption is highest when the fillet radius is 2.5 mm, the standard deviation shows a tendency to develop firstly decreasing and then stabilising, the tensile length of the torsion plate decreases slightly, and the length of the reaction force platform firstly increases and then tends to stabilise. The torsion plate energy-absorbing member is a more ideal energy-absorbing and anti-impact member, which plays a positive role in the energy-absorbing and anti-impact of the hydraulic support. [ABSTRACT FROM AUTHOR]

Regarding the vib-acoustic performance of internal coupled structures, basically all relevant studies have been confined to the classic form of connections. In this investigation, the boundary and internal elastic constraint matrices of the coupled structure are established, the vibration and sound calculation model of the coupled structure is then established, and numerical analysis is performed to show the effect of constraint stiffness on the vibration and acoustical performance of a coupled plate-cylindrical shell system. The results show that impedance matching between the structures is improved with the increase of the elastic connection stiffness, which is conducive to the vibration energy propagation. Moreover, the supporting coupling stiffness between elastic coupled structures plays an important role in vibration energy transfers. [ABSTRACT FROM AUTHOR]

In this research, we have proposed a Sn-based perovskite solar cell using solar cell capacitance software. The main aim of this study is to develop an environment-friendly and highly efficient structure that can be used as an alternative to other toxic lead-based perovskite solar cells. This work performed a numerical analysis for the proposed (Al/ZnO/SnO2/CH3NH3SnI3/Ni) device structure. The absorber layer CH3NH3SnI3, buffer layer SnO2, and electron transport layer (ETL) ZnO, with aluminium as the front contact and nickel as the back contact, have been used in this simulation. Several analyses have been conducted for the proposed structure, such as the impact of the absorber layer thickness, acceptor density, defect density, series and shunt resistances, back contact work function, and operating temperature. The device simulation revealed that the optimum thickness of the absorber layer is 1.5 μm and 0.05 μm for the buffer layer. The proposed Sn-based perovskite structure has obtained a conversion efficiency of 28.19% along with FF of 84.63%, Jsc of 34.634 mA/cm2, and Voc of 0.961 V. This study shows the upcoming lead-free perovskite solar cell's enormous potential. [ABSTRACT FROM AUTHOR]

The willingness to improve the security and reliability of power supply to end-users, often pushed by prescriptions of national regulatory authorities, is bringing considerable challenges for distribution system operators. Islanding a portion of the public distribution network after a fault is considered a measure to mitigate the effects of service interruptions. This procedure is usually carried out by counterfeeding the grid through a generator set (GenSet). Even if this approach is widely adopted around the world, reenergizing the grid and keeping the electric island stable is not a trivial task. In this framework, the scope of this paper is to provide a set of technical guidelines for the usage of GenSets to supply public grids in emergency conditions. The goal is to highlight the static and dynamic limits of the GenSet operations and simplify their exploitation for the grid operators. The numerical analyses, which have been carried out through the RMS simulation tool of the DigSilent PowerFactory software, also aim to evaluate the technical constraints in the case of active networks, which involve distributed generation implementing regulations according to ENTSO-E and Italian technical standards. [ABSTRACT FROM AUTHOR]

This research numerically investigates the mechanical behavior of sloped rolling-type bearings equipped with an inerter. After deriving equations of motion, the mechanical behavior, under harmonic excitation, of a sloped rolling-type bearing with its inherent rotational mass (i.e., considering the inertial and restoring forces generated by the existing roller) and one with an added rotational inerter is numerically analyzed. It is demonstrated that the latter is mechanically different from the former and, more importantly, the latter is more effective at controlling acceleration and displacement responses and practically more feasible. The acceleration control performance designed for sloped rolling-type bearings that ignore the inherent rotational mass can basically be retained when adding a rotational inerter if a suitable inertance-to-mass ratio can first be determined based on a specific acceleration target. Precisely stated, retaining the unique mechanical feature of sloped rolling-type bearings under harmonic excitation (i.e., the maximum transmitted acceleration is irrelevant to the external disturbance) is the optimum design objective in this study. Parametric and numerical analyses show that the peak acceleration responses of sloped rolling-type bearings with an added rotational inerter whose inertance-to-mass ratio is determined based on the optimum objective are less dependent on having a sufficiently large harmonic excitation period (i.e., on having the roller in motion within the sloped rolling range). In addition, the peak displacement responses under harmonic excitation can be effectively reduced compared with sloped rolling-type bearings that only consider the inherent rotational mass (i.e., without an added rotational inerter). Similar tendencies are seen when the sloped rolling-type bearings are subjected to ground motion records including far-field and pulse-like near-fault ones. Regardless of the ground motion considered in this study, the sloped rolling-type bearings with an added rotational inerter designed based on the optimum objective show steady displacement reduction. Finally, a simple, practical, and acceleration-based procedure is proposed for designing sloped rolling-type bearings equipped with added rotational inerters based on observations from the parametric and numerical analyses. [ABSTRACT FROM AUTHOR]

Physical laws provide a mathematical description of a physical phenomenon. The mathematical description is generally in the form of differential equations with appropriate initial and boundary conditions, called initial boundary value problems. The dimensionless form of an initial boundary value problem is the first step for the solution to a class of problems. The approach is generally applied for closed-form (or analytical) solutions, whereas practical engineering problems can only be solved numerically. Commercial finite element packages are commonly used for the numerical solution of engineering problems with complexities caused by geometry, loading, and material properties. A numerical solution does not produce a formula; therefore, a completely new solution must be obtained even for minor changes in the data set. A single-dimensionless finite element analysis would solve a class of problems. Literature shows that user-developed finite element codes, not accessible for general use, are generally used for dimensionless finite element solutions. The availability of dimensionless analysis in a commercial finite element package would be very convenient. Commercial packages do not have built-in dimensionless formulations. However, all mainstream packages allow user-implemented formulation through different coding requirements. At least one researcher has used a commercial package for dimensionless analyses without coding. The work presents a guide on alternate implementation methods of dimensionless formulations in commercial packages. A sample case demonstrates the stepwise implementation of a dimensionless formulation without writing a customized finite element code. [ABSTRACT FROM AUTHOR]

The synchronization behaviors of coupled oscillators under time-varying couplings are of both theoretical and practical significance. While recent studies show that synchronization is suppressed by time-varying coupling in general, the underlying mechanism is still not very clear. Here, by the kernel of sinusoidal coupling function, we revisit the effects of periodic coupling on the synchronization of networked phase oscillators. It is found that the suppressed synchronization by periodic coupling is attributed to the formation of synchronization clusters in the transition from desynchronization to global synchronization. The clusters are different in size and frequency but are all locked to the frequency of the periodic coupling. We demonstrate this phenomenon numerically in different network models and conduct a theoretical analysis on the numerical results based on the method of dimension reduction. The findings extend our knowledge on the dynamical responses of a complex network to external drivings, and shed lights on the mechanism of suppressed synchronization in periodically coupled oscillators. [ABSTRACT FROM AUTHOR]

SiC fiber-reinforced silicon matrix (SiCf/SiC) composites are of significant interest for the aircraft engine. The thermal conductive behaviors of [0-90-0]s SiCf/SiC composites along in-plane and out-of-plane (thickness) directions were reported in this paper. The thermal conductivity of the SiCf/SiC composite was tested by using the steady-state measuring apparatus. Then, the thermal conductivity of the SiC matrix was predicted by finite element analysis (FEA). The representative volume element (RVE) models of SiCf/SiC composites were built, and FEA was used to investigate thermal conductive behaviors. It was found that the thermal conductivity along the fiber radial direction was greater than it was in the axial direction in the SiCf/SiC composite and that the thermal conductivity of the out-of-plane direction is lower than that of the in-plane one. The thermal conductivity of the SiCf/SiC composite in the in-plane direction at room temperature was 31.1 Wm−1K−1 and 28.5 Wm−1K−1, and the thermal conductivity in the thickness direction was 24.9 Wm−1K−1. The experimental thermal conductivity showed a good agreement with the thermal conductivity of FEA. [ABSTRACT FROM AUTHOR]

Stone columns are being used to reduce soft soil settlement and increase load-carrying capacity. Since there is inadequate lateral support from the local native soil, soft soil undergoes excessive settlement under vertical loading. This issue is effectively resolved by suitably encasing stone column material by geosynthetic with significant axial stiffness, which provides the required additional confinement reported in the literature. In the current study, an effort has been made to examine the load settlement behaviour of the dual-layered geosynthetic-encased stone column (DL-GESC) under vertical loading. In order to simulate the behaviour of stone column-reinforced soft soil, a FEM analysis was performed using PLAXIS-3D and three-dimensional (3D) models made utilising the unit cell idealisation technique for a single column. The stone column diameter, spacing to diameter (s/d) ratio, and encasement layers were varied to determine their influence on load-settling behaviour. The vertical load-carrying capacity of the ground was significantly improved when an additional layer of geosynthetic encasement was inserted into the stone column as compared to SL-GESC. Improvement of 15–25% was observed for the analysis of a single column installed in soft clay, according to the result obtained. Improvement ratios have been discussed in detail for various encasement conditions. [ABSTRACT FROM AUTHOR]

With the wide application of directional drilling technology in coal mine predraining boreholes, the failure problem of the tool joint of the directional drill pipe has become one of the main factors restricting the drilling efficiency. The main reason for the failure problem of the tool joint of the directional drill pipe is the stress concentration. The stress test rig for the tool joint of the directional drill pipe is designed based on the resistance strain measurement method, and the stress of the tool joint of the directional drill pipe is tested. The tool joint's 3D finite element model was established based on nonlinear contact theory. The experiment verified the accuracy of this model. The stress distribution of the tool joint of the directional drill pipe was obtained. The research shows that the stress of the tool joint of the directional drill pipe is concentrated at the root between the third and the fourth turn of the engaged thread. The work presented in this study is a reliable guide to the design and field use of the tool joint of the directional drill pipe. [ABSTRACT FROM AUTHOR]

The squeezed multiple-branch pile is a variable section pile that was built by adding a bearing branch cavity to a constant section pile using expansion and extrusion equipment. It is widely used in engineering practice for its high bearing capacity, small settlement deformation, high economic benefits, strong adaptability, and simple pile forming process. In this paper, a new type of squeezed multiple-branch pile is proposed and its forming tool is invented. The forming tool of the pile has applied for an invention patent and is authorized by the China National Intellectual Property Administration. Multiple groups of comparison models of the new squeezed multiple-branch piles are established by using FLAC3D numerical simulation software to investigate the influence of the number and spacing of branches on the bearing mechanism in response to uplift load. The results indicated that the number and spacing of branches have a significant effect on the uplift bearing capacity, load–displacement curves, side friction resistance, and stress distribution law in the new pile and soil around the pile. The suitable number and spacing of branches maximize the uplift bearing capacity and minimize the settlement of a single pile. [ABSTRACT FROM AUTHOR]

As one of the key algorithms in supporting AV (autonomous vehicle) to complete the LC (lane changing) maneuver, the LTP (LC trajectory planning) algorithm generates safe and efficient LC trajectory for the AV. This paper proposes a novel dynamic LTP algorithm based on the quintic polynomial curve. This algorithm is capable of adjusting LC trajectory according to the state changes of the surrounding driving environment. The formulation of our proposed algorithm mainly consists the underlying form of trajectory equation, the optimization objective function, the corresponding constrains, and the SQP (sequential quadratic programming) algorithm. For each planning step, the time-based quintic polynomial function is introduced to model the trajectory equation. The problem of solving the parameters of the corresponding equation is then transformed into an optimization problem, which takes driver's safety, comfort, and efficiency into account. After that, the SQP algorithm is employed to solve this optimization problem. Finally, both numerical simulation and field-data validation are used to verify the effectiveness of our proposed algorithm. We anticipate that the research could provide certain valuable insights for developing more reliable LC algorithms for AVs., Author(s): Yang Li [1]; Linbo Li (corresponding author) [1]; Daiheng Ni [2] 1. Introduction Numerous research studies indicate that the advent of AVs (autonomous vehicles) could significantly enhance traffic safety, [...]

To alleviate the lane-changing conflicts between weaving vehicles and enhance the traffic efficiency in the weaving section of urban expressway under the connected autonomous vehicle (CAV) environment, a cooperative lane-changing strategy for CAVs is proposed. The strategy consists of an upper layer of decision making, which determines the lane-changing sequences of weaving vehicles based on their lane-changing advantages quantified by a set of utility functions, and a lower layer of control, which generates detailed instructions of speed adjustments and lane-changing manoeuvres for weaving vehicles. To verify the effectiveness of the proposed strategy under different traffic demand settings, a numerical simulation, including a base case and a control case, is conducted. Then, to further verify the effectiveness of the proposed strategy for the mixed traffic state and compare its performance with the existing CAV lane-changing method, benchmark and comparison tests with six different market penetration rates (MPRs) of CAVs are carried out under the congested demand setting. In addition, the delay improvement ratio, inverse time-to-collision, and ratio of large deceleration time are selected as performance indicators to investigate the effect of the proposed strategy on enhancing the operational efficiency, traffic safety, and passenger's comfort within the weaving section. According to the simulation results, the overall efficiency, safety and comfort in the weaving section under the CAV environment, are all improved, when the proposed strategy is applied to weaving vehicles. The proposed strategy is also superior to the existing CAV lane-changing method on maintaining traffic efficiency and safety. Therefore, the proposed cooperative lane-changing strategy, based on CAV technologies, shows good potential in solving the problem of lane-changing conflicts within the weaving section and facilitating the traffic management and traffic control of urban expressway., Author(s): Zhi Zhou [1,2]; Linheng Li [1,2]; Bin Ran (corresponding author) [1,2]; Xu Qu (corresponding author) [1,2] 1. Introduction Urban expressway, which has the characteristics of large capacity, high speed, [...]

This study investigated the thermal protection performance of an active jet thermal protection system (PRsAJ-TPS) based on a new jet design parameter PRs for hypersonic flight vehicles (HFVs). The new parameter PRs is defined as the relationship between the jet flow total pressure and the free flow total pressure behind the outer bow shock. A 20° tilted nozzle design is employed together with the PRs to form the PRsAJ-TPS. Theoretical and numerical analysis is performed to prove the advantages of using the PRs. A conventional in-house CFD solver with the k ‐ ω SST turbulence model is utilized to perform the calculation. The influence of different PRs (working in the short penetration mode) and flight angles of attack on the performance of the PRsAJ-TPS is also studied. The simulation results confirmed that with a constant PRs, the Mach disk location stays the same and the normalized heat flux reduction is similar at different flight conditions. Nearly linear relationships exist between the new design parameter PRs and thermal protection performance indicators. The PRsAJ-TPS also exhibits good protection when flight angle of attack (AoA) varies between 0° and 40°, with the best results achieved at AoA = 0 ° . This study provides valuable information for the engineering application of the jet-based TPS to future HFVs. [ABSTRACT FROM AUTHOR]

Owing to pipe thinning, fatigue damage, and aging, pipes, valves, and devices installed in the primary and secondary systems of nuclear power plants may leak high-temperature/high-pressure reactor coolant. Thus, a system must be developed to determine if the leakage is exceeding the operating limit of the nuclear power plant, thereby mitigating any loss of life or economic loss in such cases. In this study, a validated numerical analysis method was established to initially simulate the leakage behavior and subsequently to evaluate the small amount of leakage in the compartment. For this purpose, a vapor-jet collision test in the compartment and a vapor-jet test in the pipe were performed; numerical analysis was conducted, and comparative analysis was performed to verify the validity of the established method. The evaluation results suggested that the proposed numerical analysis method could optimally simulate the flow characteristics of the steam jet. Notably, compared to the existing evaluation method, the proposed approach simulated a more detailed behavior of the jet formed at the leakage point. In future research, the results of this study (data) will be used to inform the design of the second phase of the leak-capture system and will be served as the foundation for a performance-optimization study on the capture system. [ABSTRACT FROM AUTHOR]

To study the aseismic performance after the reinforcement of the mortise-tenon joints of folk houses with traditional Chuan-Dou style wood structure and their steel plate, test specimens of joints—two for Tou mortise-tenon joints, two for Ban mortise-tenon joints, and two for dovetail mortise-tenon joints—were fabricated out of hemlock, and steel plates were utilized to reinforce one of the joint specimens of each type on the middle part of the mortise-tenon joint. By carrying out pseudo-static tests on the joints and building ABAQUS numerical model; the position where the mortise-tenon joints were to be reinforced by the steel plates was optimized for a comparative analysis into the test results on reinforced and unreinforced mortise-tenon joints and the numerically simulated bending moment-turning angle hysteresis curve, skeleton curve, energy-dissipating capacity, and rigidity degeneration curves. The results showed the following: the pulling-out phenomenon of tenons was severe, and the aseismic performance of Tou tenons was superior to Ban tenons and dovetail tenons; reinforcing the middle part of mortise-tenon joints with steel plates could effectively reduce the pulling-out amount of joints and promote the aseismic performance of mortise-tenon joints but have an insignificant promotive effect for the bearing capacity of Tou mortise-tenon joints; the aseismic performance was improved significantly after the flat steel strip reinforced position was moved to the upper and lower ends of mortise-tenon joints, with the ultimate bearing capacities being 1.5∼2.4 times that on the middle part of flat steel strip reinforced joints. [ABSTRACT FROM AUTHOR]

Investigating the shear failure caused by the concentration of compressive stress around noncircular boreholes is important both in the field and in the laboratory. This article deals with the numerical analysis of elliptical boreholes under a nonisotropic in situ stress field using the Mogi–Coulomb nonlinear failure criterion. The purpose of the presented numerical model is to simulate the progressive shear failure (breakout) around the borehole and investigate the impact of the eccentricity of the borehole on the stability and depth and width of the failure area. According to the obtained results, the breakout is V-shaped and is formed along the minimum principal stress. As the eccentricity of the borehole increases, the final dimension of the breakout becomes smaller; in other words, the increase in ellipticity strengthens the borehole against shear failure. However, as the eccentricity increases, the stress concentration at the breakout tip increases. Another finding of the study conducted in this article is the significant relationship between the width and the depth of the breakout failure, which makes the idea of estimating both horizontal in situ stresses using breakout dimensions seriously doubtful. Also, the interesting result obtained is that the stress concentration factor at the breakout tip for boreholes with different eccentricities is the same at the end of the breakout. [ABSTRACT FROM AUTHOR]

The temperature is a critical factor that determines the unfrozen water content and ice content in the frozen soil. In view of mechanical properties of the frozen soil depend on the volume of components of the four-phase systems, thus the temperature has a significant impact on the mechanical behaviors and deformation properties. The thermal state of the embankment in permafrost regions has a significant seasonal difference, then the seismic performance of the embankment alters with the season. In addition, the seismic performance is highly influenced by the properties of the earthquake motion, especially the seismic intensity. Combining these factors, a numerical simulation was conducted in this study. In this study, taking a typical section of Qinghai-Tibet Railway as an example, a numerical case study on the seismic behavior of embankment was carried out using the dynamic explicit FEM code ABAQUS/Explicit. The El Centro excitation with different intensities was performed in numerical analysis and two distinct thermal states of the embankment in extreme cold and warm days were considered as well. The seismic behaviors of the embankment, including the acceleration responses, the strain response, and the displacement response, were studied effectively. This paper proposes approaches and methods to study the seismic failure mechanism of the infrastructures, and the results can serve as a scientific basis for resisting earthquakes and preventing disasters in cold regions. [ABSTRACT FROM AUTHOR]

As the composite pile, the precast concrete piles reinforced with cement-treated soil (PCCS) is formed by driving the precast cement (PC) pile into the deep mixing (DM) column, which has been successfully and widely utilized to support buildings and embankments over soft soil. To increase the pile spacing and give full play to the economic merits of the PCCS, a reinforcement scheme, which involves the combined use of rigid piles and flexible columns, employing penetrated PCCSs and floating DM columns is proposed and utilized for soft soil ground treatment. However, there is a lack of feasible method for consolidation behaviors of this combined composite foundation (CCF) reinforced with penetrated PCCSs and floating DM columns under flexible loads. This paper developed an analytical solution to predict the average consolidation degree of this CCF based on a cylinder consolidation model and double-layer ground consolidation theory. The excess pore pressure and average consolidation degree were calculated by considering the composite pile penetration into the cushion. The analytical method agrees well with results obtained by numerical analysis. Additionally, a parametric study was conducted systematically to analyze the effect of key influence factors on the average consolidation degree of this CCF. The results indicate that the consolidation rate of this CCF can be much faster than that of the natural ground. The consolidation rate strongly depends on the compressive modulus and area replacement ratio of PCCSs. The increasing inner core-outer core modulus ratio and the inner core-subsoil modulus ratio increase the consolidation rate of this CCF. In addition, the consolidation rate increases with the gravel cushion-subsoil modulus ratio, while it decreases with the loading period. [ABSTRACT FROM AUTHOR]

This paper proposes the optimal design and simulation analysis of a robot for tree-climbing, which has the ability to climb up the tree trunk to adapt to different tree diameter changes. In an unstructured forest environment, considering that the Tree-Climbing Robot (TCR) may collide with branches, reducing the success rate of tree climbing, the mechanical structure and movement strategy to avoid branches are predesigned. The presented TCR mimics several design principles that have been adapted to arboreal animals, including claw-hand grasping and climbing gait movements, and is optimally designed to achieve high manoeuvrability on irregularly shaped trees. Based on the D-H parameterization method, the kinematics model of the TCR is developed and its kinematic equations are solved. The accuracy of the kinematic equations is verified by MATLAB, and the reachable area of the working space of the manipulator of the TCR is determined. Using ADAMS to analyse the kinematics and dynamics of the climbing process of the TCR, the rationality of the gait planning of the robot is verified, and the time-varying characteristic curves of each physical quantity of each structural joint are derived and further simulated through numerical analysis, the results of which will profoundly validate the technical feasibility and design innovation of this presented TCR. [ABSTRACT FROM AUTHOR]

To ensure safe exploitation of the Muduchaideng Mine, we use a numerical simulation to invert the in situ stress field based on observation data from GPS stations, investigate differences in movement velocities at different locations, and analyze the lefthanded movement in the area around the wellfield. The relationship between the difference in motion velocity and the in situ stress field was explained through theoretical analysis. The law of in situ stress distribution was studied using data collected from the surrounding mines, and a regression equation as well as the relationship between the magnitudes of the three-way stresses was obtained. The inversion results were consistent with the measured data, indicating that inversion of the in situ stress field was accurate under the conditions found in the intact Ordos block. Additionally, the influence of tectonic stress on the key layer was larger than that on the bedrock of the coal seam roof, and the energy accumulated in the key layer was higher. The stress concentration coefficient of the key layer was similar to the variation law of the coal seam thickness. Therefore, the southwest area of the wellfield with a thicker coal seam is the key area for impact ground pressure prevention and control. [ABSTRACT FROM AUTHOR]

Theoretical analysis and numerical simulation were conducted to study the disaster-causing mechanism of structural instability of the overlying strata induced by water–rock coupling and effectively prevent and control the powered support jammed accident during mining below the unconsolidated confined aquifer. The influencing factors on the stability of the overlying strata structure were analyzed, and the numerical simulation method of unconsolidated confined aquifer was designed. The disaster-causing mechanism and the evolution process of the stress–displacement–crack field of the overlying strata induced by water–rock coupling were discovered. Meanwhile, the prevention measures for the structural instability of the overlying strata were proposed and verified in some engineering practice. Results show that the stability of the overlying strata structure reduces with the increase in hydraulic pressure, the breaking interval of the main roof, and the decrease in the overlying strata strength and waterproof coal pillar height. The overlying strata structure keeps a stable equilibrium state before the fracture planes through a whole waterproof coal–rock pillar. When the hydraulic pressure is small or the bedrock surface is a thick topsoil layer, the sliding block is in a state of limit equilibrium for the decrease of pressure on the sliding block while the fracture planes through a whole waterproof coal–rock pillar because of the action of unloading during an overlying strata movement. When the hydraulic pressure is high, the pressure on the sliding block remains constant at about hydraulic pressure, and the intact shear fall of the sliding block occurs as a result of the hydraulic pressure of the confined aquifer and the weight of the sliding block, which may result in a powered support jammed accident. However, this type of accident can be prevented by drainage for decreasing hydraulic pressure, presplitting blasting of the hard main roof, overlying strata grouting reinforcement, and increasing the height of the waterproof coal–rock pillar. [ABSTRACT FROM AUTHOR]