Stability Coefficient Research Articles

Application graph theory to evaluate the stability of landslide slopes

Evaluation of the stability of slopes is a complex and important engineering task, the solution of which requires the analysis of a significant number of factors. Many different methods of slope stability calculation have been developed to solve this type of problem. However, two groups of methods - limit equilibrium methods and the finite element method (FEM) - have become the most widely used. However, these methods have certain disadvantages. Limit equilibrium methods are limited by the assumptions used during the calculation, including the hypothesis of a solid compartment, which does not allow analyzing the stress-strain state. The FEM of the elements does not make it possible to unambiguously localize the sliding surface of the slope, and the determination of the stability coefficient using the method of reducing the strength of the soil requires a large number of complex iterative calculations. The methods and approaches of graph theory can be used precisely to combat the shortcomings of FEM. The paper examines the basics of graph theory. The main methods of specifying graphs, as well as certain types of graphs with an indication of their key features, are presented. The concept of isomorphism of graphs and some features of their graphical representation are revealed. The article presents the basic idea of using graph theory to calculate the stability of slopes. The main questions that must be solved when applying graph theory to the given type of problem are outlined. Two methods of converting a mesh of finite elements into a graph are considered in detail. The advantages and disadvantages of the proposed methods are analyzed. The transformation of the calculation scheme of an imaginary slope with a given geometry, which was simulated in the LIRA-SAPR software complex, into graphs using the above methods is demonstrated. An overview of the approaches that can be used to create a graph weight function is given.

PentaPod: A new type of concrete armor for coastal protection

This paper explores PentaPod, an invention in concrete armor units developed to protect coastal areas from damage caused by waves and currents. Until now, there hasn't been an armor unit intentionally designed to enhance its stability through connections with neighboring units. PentaPod provides a novel perspective, suggesting that the stability of armor units can be significantly improved not only by having substantial weight and effective interlocking but also by securely connecting them to each other. With this in mind, PentaPod concrete armor can be installed in a random or regular manner without the need for fasteners. Alternatively, it can also be installed regularly in layers with fasteners. Compared to conventional concrete armor installations, the overall stability of structures is significantly improved with interconnected PentaPod, either partially or entirely. In this paper, the results of testing the Stability Coefficient (Kd) for two variations of armor, namely PentaCone and PentaOcta, tested in a Wave Tank are also presented. The objective of this testing is to ascertain the stability coefficient for both variations of armor when installed randomly or regularly without any tying involved. The PentaPod arrangement allows for the implementation of both Grey Protection (using concrete armor) and Green Protection (conservation of mangrove areas) simultaneously, showcasing its versatility and integrated approach to coastal protection.

The sufficiency of the State’s economic capabilities to ensure the necessary level of defense needs forecasting improving method

The concept of sufficiency is closely related to the economic forecasting ability to set realistic and achievable goals for the economy as a whole development. Forecasting opportunities is a critically important tool that takes into account the current State of the economy, sets goals for future development, and also determines the necessary tools of State regulation to achieve them. Ultimately, the adequacy of economic opportunity can be assessed using these forecasting approaches because they aim to balance what is realistically achievable against the current State of the economy. The initial step in this process involves the formation of conceptual approaches that pave the way to the creation of acomprehensive system of forecasting the economic capabilities of the State to ensure the necessary level of defense needs. The article presents the results of the assessment of the individual economic capabilities of such countries as Norway, France, Finland, the USA, Sweden, Great Britain and Israel, taking into account the level of economic stability of the countries and the coefficients of stability of changes. By means of an expert survey, a list of possible threats and scope of implementation of different levels of protection was determined, taking into account the dependence of defense needs on the stability of funding and the stability of its changes. The averaged values of the limits of the corresponding levels of defense needs until 2033 inclusive are also determined. To predict the sufficiency of the State's economic capabilities ensuring the necessary level of defense needs, the Lagrange interpolation method was used, with the help of which 5possible directions of the development of the situation were identified. The results of using the appropriate method were the provision of recommendations based on the following characteristics: for countries that do not meet the selection criteria (Lithuania, Latvia, Estonia, Germany, Hungary and Poland); for countries with a "wave-like" trend, which characterizes the instability of State policy (France and Finland); for countries with a "wave-like" trend and a high potential for self-sufficiency and characterized by the instability of State policy (Norway); for countries that have the potential for gradual growth, using their own economic opportunities; may be characterized by over Stated defense needs (USA, Sweden and Great Britain); for countries with a high potential of their own capabilities (Israel). Thanks to this distribution, it is possible to examine potential future trends in the development of economic capabilities of countries and compare them with the determined levels of defense needs.

Numerical analysis on global stability performance of fold-fastened multi-cellular steel walls

As a novel cold-formed steel (CFS) built-up closed member, the global stability performance of fold-fastened multi-cellular steel wall (FMSW) under axial compression was numerically investigated in this paper. Firstly, finite element (FE) models of FMSWs that could precisely simulate the global buckling were developed using ABAQUS and validated by existing experiments of CFS built-up members. Then, eight groups of numerical examples were analyzed to explore the effect of different parameters on the global stability performance of FMSWs, including the geometrical dimensions, material property, indented spacing and initial imperfection, where the corresponding global stability coefficients (φ) of FMSWs could be obtained from FE results. The normalized slenderness ratio (λn) of FMSWs was calculated based on the concept of the effective width method (EWM). Finally, the FE results of (φ, λn) were compared with existing stability design curves of steel structures in various codes. It was found that the stability design curve-d specified in Chinese code GB 50017–2017 could achieve a conservative design, and it could provide a valuable reference for designing slender FMSWs in practice.

Stability capacity design of shuttle-shaped restrained-buckling braces with uniform cross-section at mid-span

This paper proposes a shuttle-shaped buckling restraint brace (SS-BRB) with the uniform core and the peripheral restraint system that consists of uniform cross-section tube at its mid span and tapering sections at its two ends. This type of BRB maned as SS-BRB-UCS adopts circular steel tubes in the core and the peripheral restraint system. An isolation system is strategically positioned between the core and the peripheral restraint system to effectively transmit lateral loads. Obviously, this type of the optimizing peripheral restraint system could reduce material utilization with an economic design and beautiful appearance. First, the finite element (FE) model of the SS-BRB-UCS is established, then the elastic buckling performance investigation is carried out to determine the elastic buckling load formula through fitting techniques of numerical results, so as to obtain the formula of the restraint ratio. Additionally, an elastic-plastic stability bearing capacity analysis is conducted for the SS-BRB-UCS to assess its load-bearing capabilities, and the corresponding relationships between stability coefficient (φ) and the restraint ratio (ζ) is established to determine the lower restraint ratio (namely threshold) for static load-bearing capacity BRB design. Finally, the hysteretic responses of SS-BRB-UCSs subjected to axial compressive-tensile cyclic loads are studied numerically, and the corresponding lower limit of restraining ratio of SS-BRB-UCSs is proposed for their energy-dissipation design. Those two lower limits of restraining ratios of the SS-BRB-UCSs obtained in this study provide fundamentals for preliminary static and seismic designs of SS-BRB-UCSs.

Study on the conductivity of metal-based epitaxial graphene with vacancy defects and anharmonic effects

Metal-based epitaxial graphene exhibits extremely high conductivity at room temperature, making the study of its conductance crucial for understanding electron transport mechanisms in two-dimensional materials. In this paper, we applied solid-state physics theories and methods to investigate factors influencing the conductivity of metal-based epitaxial graphene. We considered the variation of conductivity and its temperature stability coefficient with temperature, taking into account the anharmonic vibrations of atoms, and explored the impact of anharmonic effects on conductivity. Using copper-based graphene as an example, we established relationships between temperature and several key parameters: electronic conductivity (σe), conductivity contributed by electron–phonon interactions (σp), conductivity contributed by vacancy defects (σn), and total conductivity (σ), along with its temperature stability coefficient (ασ). All research results were obtained within the temperature range of 300 K to 1200 K. The study reveals that σ decreases nonlinearly as temperature increases, with a magnitude on the order of (Ω ∙ m)-1, which is approximately equal to σp. The conductivity of copper-based epitaxial graphene is found to be greater than that of lithium-based epitaxial graphene. The anharmonic effects of atomic vibrations increase σ, and this increase is more pronounced at higher temperatures. The temperature stability coefficient ασ rapidly decreases with increasing temperature before tending to a constant, indicating that conductivity exhibits better temperature stability at higher temperatures. This paper provides theoretical guidance for understanding electron transport characteristics of metal-based epitaxial graphene and contributes to the design and application of high-performance electronic devices.

Experimental Study on the Effect of Wind on Armor Stone Stability

Wind is a significant factor influencing the stability of breakwater armor stones. However, few existing studies have considered the effects of wind on these structures. In this study, two-dimensional laboratory experiments were conducted to examine the effect of wind on the stability of breakwater armor stones. The stability factor (KD) of the armor stone, fluid velocity, runup, and rundown were observed under the action of waves and winds. A wind turbine was installed in front of the physical model of the breakwater to generate extreme wind conditions of 5.5 and 12 m/s. The results showed that KD decreased by 42.18% at 5.5 m/s and 57.82% at 12 m/s compared with that without wind. The maximum runup and rundown heights increased with wind velocity, following a Rayleigh distribution. The fluid velocity distribution conformed to a normal distribution, with the mean velocity directed offshore. Many studies have suggested that runup, rundown, and fluid velocity are the main factors affecting the stability of breakwater armor stones. The analysis revealed that wind affects these factors and lowers the stability coefficient. These wind-induced hydrodynamic changes suggest the need for a detailed hydrodynamic review of wind-wave conditions.

Slope Deformation Mechanisms and Stability Assessment under Varied Conditions in an Iron Mine Waste Dump

The instability of geological slopes in mining environments poses a significant challenge to the safety and efficiency of operations. Waste Dump#2 at the Ziluoyi Iron Mine in China is a notable case study that highlights the challenges associated with sizable base slopes and large step heights. To address hidden hazards in the mine and the above issues, an inclusive investigation is carried out to examine the physical and mechanical properties of the soil–rock slope through indoor testing and analyze the deformation mechanisms of the slope using numerical simulations, taking various factors into account. The study reveals that the stability of Waste Dump#2 is deeply affected by weight, groundwater conditions, earthquake loading, and rainfall. To this end, the cohesion and internal friction parameters of the soil–rock slope are first determined through direct shear tests, which show a cohesion of 6.215 kPa at the top of the slope and an internal friction angle of 34.12°. By adopting GEO-SLOPE, 3D Mine, and AutoCAD software, stability calculations of the slope are performed, which give stability coefficients of 1.547 under normal conditions, 1.276 in rainfall, and 1.352 in seismic conditions. These results meet safety standards and ensure the safe and efficient operation of the mine.

Erosion mechanism of point bar retreat under the protection of a flexible mattress

Channel retreat can be responsible for the significant loss of banks, farmland, and wetlands, leading to drastic changes in fluvial sediment and local river regimes. Although current studies focus on the erosion process of natural river channels, the mechanism by which revetments, such as the flexible mattress, influence bank evolution is still unclear. Hence, by conducting a generalized model experiment, this study investigates the point bar failure process under the mattress protection, i.e., the episodic event when the soil reaches the static equilibrium state. Specifically, a scour hole develops at the junction between the soft and hard materials, causing mattress suspension on the bank toe’s side wall and resulting in a reduction coefficient for transverse scouring rate ranging from 0.08 to 0.15. Based on the theories of soil mechanics and river dynamics, the critical conditions for point bar instability were deduced, and a mechanical model describing its erosion process under the mattress protection was established. Furthermore, our model calculated the bank morphology and total erosion volume at different periods in the flume experiment, demonstrating a good agreement with the measured data. Additionally, variations in stability coefficient and forces exerted on soil (including shear strength, gravity, and fluid pressure) of the typical sections during point bar retreat were analyzed. Sensitivity analysis of the bank toe stability emphasized the controlling effect of soil mechanical properties and the negative feedback of mattress weight. The results reveal the interaction mechanism between the mattress protection and point bar failure, theoretically guiding the bank erosion strengthening and river management planning.

Global stability design of double corrugated steel plate shear walls under combined shear and compression loads

As a novel structural component, the Double Corrugated Steel Plate Shear Wall (DCSPSW) is formed by interlocking two corrugated steel plates using high-strength bolts. This paper investigates the global stability design methods for DCSPSWs under combined shear and compression loads. Firstly, this paper examines the elastic buckling performance of DCSPSWs under horizontal shear loads and vertical compression loads separately. A bolt spacing factor (η) is introduced to reflect the influence of bolt spacing on the elastic buckling stress of DCSPSWs. Then, based on extensive finite element analysis (FEA), this paper investigates the elastoplastic buckling behavior of DCSPSWs under shear loads and compression loads and establishes the corresponding stability curves to predict ultimate load-bearing capacity. It is found that the stability coefficients (φs and φc) are closely related to the normalized slenderness ratios (λns and λnc). A smaller bolt spacing allows the DCSPSWs to exhibit improved elastic and elastoplastic stability. Finally, this study investigates the load-bearing performance of DCSPSWs under combined shear and compression loads and proposes the design formulas. The results show that the correlation curve of N/Nu-V/Vu can provide a conservative and accurate design. The research findings of this paper are advantageous for promoting the application of the innovative DCSPSWs.

Monolithic Two-Terminal Tandem Solar Cells Using Sb2S3 and Solution-Processed PbS Quantum Dots Achieving an Open-Circuit Potential beyond 1.1 V.

Multijunction solar cells have the prospect of a greater theoretical efficiency limit than single-junction solar cells by minimizing the transmissive and thermalization losses a single absorber material has. In solar cell applications, Sb2S3 is considered an attractive absorber due to its elemental abundance, stability, and high absorption coefficient in the visible range of the solar spectrum, yet with a band gap of 1.7 eV, it is transmissive for near-IR and IR photons. Using it as the top cell (the cell where light is first incident) in a two-terminal tandem architecture in combination with a bottom cell (the cell where light arrives second) of PbS quantum dots (QDs), which have an adjustable band gap suitable for absorbing longer wavelengths, is a promising approach to harvest the solar spectrum more effectively. In this work, these two subcells are monolithically fabricated and connected in series by a poly(3,4-ethylene-dioxythiophene) polystyrene sulfonate (PEDOT:PSS)-ZnO tunnel junction as the recombination layer. We explore the surface morphology of ZnO QD films with different spin-coating conditions, which serve as the PbS QD cell's electron transport material. Furthermore, we examine the differences in photogenerated current upon varying the PbS QD absorber layer thickness and the electrical and optical characteristics of the tandem with respect to the stand-alone reference cells. This tandem architecture demonstrates an extended spectral response into the IR with an open-circuit potential exceeding 1.1 V and a power conversion efficiency of 5.6%, which is greater than that of each single-junction cell.

A Review of Friction Dissipative Beam-to-Column Connections for the Seismic Design of MRFs

The use of friction-based beam-to-column connections (BCCs) for earthquake-resistant moment-resistant frames (MRFs), aimed at eliminating damage to beam end sections due to the development of plastic hinges, has been prevalent since the early 1980s. Different technical solutions have been proposed for steel structures, and some have been designed for timber structures, while a few recent studies concern friction joints employed in reinforced concrete structures. Research aimed at characterizing the behavior of joints has focused on the evaluation of the tribological properties of the friction materials, coefficient of friction, shape and stability of the hysteresis cycles, influence of the temperature, speed of load application, effects of the application method, stability of preload, the influence of seismic excitation characteristics on the structural response, statistical characterization of amplitude, and frequency of the slip excursion during seismic excitation. Studies aimed at identifying the design parameters capable of optimizing performance have focused attention mainly on the slip threshold, device stiffness, and deformation capacity. This review compiles the main and most recent solutions developed for MRFs. Furthermore, the pros and cons for each solution are highlighted, focusing on the dissipative capacity, shape, and stability of hysteresis loops. In addition, the common issues affecting all friction connections, namely the characteristics of friction shims and the role of bolt preload, are discussed. Based on the above considerations, guidelines can be outlined that can be used to help to choose the most appropriate solutions for BCCs for MRFs.

Analysis and Prevention of Rock Burst Risk of Working Face under the Influence of Continuous Irregular Triangular Coal Pillar Stress Concentration Area.

Irregular coal pillars inevitably appear in the layout of the current long-wall mining method, which easily forms stress concentrations and becomes a heavy disaster area of rock burst. In order to solve the impact risk of irregular coal pillar working face, it is necessary to study the instability mechanism of the coal pillar and put forward effective prevention and control measures. Based on the research background of 14320 working face of the Dongtan Coal Mine in the Yanzhou mining area of China, this paper studies the prediction and prevention of rock bursts in this kind of coal pillar by means of theoretical calculation, numerical simulation, engineering analogy, and field monitoring. The results show that (1) the absolute stability of coal pillar is that the width of coal pillar B reaches twice the support pressure of 2L, and the possibility of instability from large to small is coal pillars 2, 5, 3, 1, and 4. (2) The ratio of coal pillar strength to its average load determines the stability coefficient of the coal pillar, and it is judged that coal pillars 1 and 4 are in a stable state, coal pillars 3 and 5 are in a limit equilibrium state, and coal pillar 2 is in an unstable state. The numerical simulation shows that the maximum stress value inside the coal pillar during the mining process is basically consistent with the theoretical calculation of the bearing strength of the coal pillar. (3) The new evaluation method is used to evaluate the rock burst risk degree of the working face roadway: 156.75 m is a strong rock burst risk zone, 728.18 m is a medium rock burst risk zone, and 176.88 m is a weak rock burst risk zone. (4) Regional prevention and local prevention measures are proposed for the risk of rock burst in the roadway, which reduces the stress concentration of the coal pillar. It is verified that the pressure relief effect is remarkable, and the safe mining of such an irregular coal pillar working face is completed, which provides a solution for studying and solving such rock burst risk.

Global stability design of concrete-filled corrugated steel tubular columns

In recent years, various types of concrete-filled steel tubular (CFST) columns were proposed and they have been widely used in engineering practice. Considering the great confinement effect of corrugated steel plate on the concrete, a novel type of CFST column called concrete-filled corrugated steel tubular (CFCST) column was proposed. The CFCST column consists of horizontally corrugated steel plates, corner steel bars and infilled concrete. In this paper, the stability performance of CFCST columns is studied. Firstly, a finite element (FE) model was developed for numerical simulation. The ultimate resistances, load-displacement curves and failure modes obtained from the FE models were compared with previous test results to verify the validity of the FE model. Subsequently, seven sets of numerical examples were analyzed to investigate the impact of key parameters on the global stability performance of CFCST columns. These examples involved variations in geometric dimensions, corrugation shapes and material strengths. Finally, the stability coefficients φ of CFCST columns obtained from FE numerical simulation were compared to several existing stability curves. On this basis, a new stability curve was proposed for predicting the global stability resistance of CFCST columns with good accuracy and reasonable redundancy.

Network visualization to interpret which healthcare services are central to people living with HIV.

To employ network analysis to identify the central healthcare service needs of people living with HIV (PLWH) for integrated care. Cross-sectional survey. A list of healthcare services was identified through literature reviews, expert workshops and validity evaluations by PLWH. A total of 243 PLWH participated at five hospitals and self-reported their need for healthcare services on a four-point Likert scale. Centrality of healthcare service needs was analysed using network analysis. The mean score for 20 healthcare service needs was 3.53 out of 4. The highest scoring need, "Precaution for interaction between antiretroviral therapy and other drugs," received a rating of 3.73 but had a centrality of only 0.31. The most central node in the network of healthcare service needs, "Information and coping with opportunistic infections," had a strength centrality of 1.63 and showed significant relationships with "non-HIV-related medical services (e.g., health check-ups)" and "Regular dental services." The correlation stability coefficient, which quantifies the stability of centrality, was 0.44 with an acceptable value. The most central need was information on opportunistic infections that had connections with many nodes in network analysis. By interpreting the relationships between needs, healthcare providers can design interventions with an integrative perspective. Network visualization provides dynamic relationships between needs that are unknown from the score scale by presenting them graphically and qualitatively. Using network analysis to interpret need assessment offers an integrated nursing perspective. Coping with opportunistic infection is central to connecting the chain of healthcare. This study highlights the multifaceted understanding of patients' needs that nurses gain when they conduct network analysis. We adhered to the STROBE checklist. No patient or public contribution.

Bond theory, vibrational spectroscopy, and dielectric responses of trirutile ATa2O6 (A = Mg, Ni) microwave ceramics

This study established the connection between structure and dielectric responses by synergistically evaluating the chemical bond characteristics and lattice vibrational spectroscopies of trirutile ATa2O6 (A = Mg, Ni) microwave ceramics. The MgTa2O6 ceramic exhibits a uniform grain size distribution and a dense microstructure, with dielectric characteristics at microwave range of a εr value of 27.27, a high Q×f value of 109,203 GHz (8.73 GHz), and a τf of approximately 53.38 ppm/°C when sintered at 1300 °C, while the NiTa2O6 ceramic presents a smaller average grain size and minor micropores, with dielectric characteristics at microwave range of εr = 24.58, Q×f = 27,610 GHz (9.25 GHz), and τf = 33.94 ppm/°C, sintered at 1250 °C. The structural refinement and atomic arrangements confirm a trirutile structure along the [001], [100], and [3 3‾1‾] zone axes. Ta–O bonds are found to contribute the most to the ionic character of a bond, bond susceptibility, lattice stability, thermal expansion behaviors, and strength of bonding ability, indicating their significant influence on dielectric polarization, lattice stability, and temperature coefficient of resonant frequency. Raman scattering spectra analysis reveals that the A1g mode near 700 cm−1 mainly controls the Raman vibrational behaviors. The theoretical dielectric properties calculated from the infrared spectrum and dielectric properties analysis consistent with the measured dielectric performances, suggesting that the dielectric characteristics at the microwave range are mainly determined by the oscillatory absorption of structural phonons, with the first two modes at 210.48 cm−1 and 232.87 cm−1 contributing 72.02% to the εr value and 90.45% to the tanδ value, respectively.

Univariate Flux Partition Functions for Planetary Boundary Layer Schemes at Gray Zone Resolutions

Abstract When the horizontal grid spacing of a numerical weather prediction model approaches kilometer scale, the so-called gray zone range, turbulent fluxes in the convective boundary layer (CBL) are partially resolved and partially subgrid scale (SGS). Knowledge of the partition between resolved and SGS turbulent fluxes is key to building scale-adaptive planetary boundary layer (PBL) schemes that are capable of regulating the SGS fluxes with varying grid spacing. However, flux partition depends not only on horizontal grid spacing, but also on local height, bulk stability of the boundary layer, and the particular turbulent flux. Such multivariate functions are difficult to construct analytically, so their implementations in scale-adaptive PBL schemes always involve certain levels of approximation that can lead to inaccuracies. This study introduces a physically based perspective for the flux partition functions that greatly simplifies their implementation with high accuracy. By introducing an appropriate scaling length λ that accounts for both height and bulk stability dependencies, the dimensionality of the partition functions is reduced to a single dimensionless group. Based on the analysis of a comprehensive large-eddy simulation dataset of the CBL, it is further shown that λ’s height and bulk stability dependencies can be separately represented by a similarity length scale and a stability coefficient. The resulting univariate partition functions are incorporated into a traditional first-order PBL scheme as a proof of concept. Our results show that the augmented scheme well-reproduces the SGS fluxes at gray zone resolutions. Significance Statement Flux partition functions are a key component in most scale-adaptive planetary boundary layer (PBL) schemes developed for kilometer- and subkilometer-resolution numerical weather prediction models. They regulate the parameterized turbulent fluxes as a function of horizontal grid spacing, while they also depend on height and atmospheric stability. Such multivariate dependencies forbid simple analytical expressions, and as a result, partition functions implemented in scale-adaptive PBL schemes are generally simplified at the cost of accuracy in previous works. This study investigates the possibility of constructing partition functions that are both accurate and easy to parameterize. Utilizing a physically based length scale, univariate partition functions are built, evaluated, and put into a conventional PBL scheme to improve the gray zone turbulence parameterization.

Utilizing Artificial Neural Networks for Entry Vehicle Aerodynamic Characterization

Determining the dynamic stability of blunt body entry vehicles is a persistent engineering challenge, particularly in the low supersonic to subsonic flight regime where the behavior of the unsteady wake is a primary contributor. Dynamic stability quantities are determined by fitting measurements of a ballistic range campaign or a computational fluid dynamics (CFD) computational experiment to an assumed functional form in order to regress quasi-static stability coefficients. However, this data reduction process has many implicit assumptions that may not hold. This paper explores novel alternatives to the established methods for modeling blunt body aerodynamics. A six-degree-of-freedom CFD-in-the-loop flight model is used to run “virtual ballistic range tests,” fully capturing the relevant flow physics. Feed-forward and time-delay neural network models are fitted to the time-series trajectory and aerodynamic results, which can then be used to predict aerodynamic forces and moments. These models do not have a prescribed functional form and do not assume linearized aerodynamics. The models are evaluated for goodness-of-fit in their aerodynamic and trajectory prediction. The feed-forward neural network model resulted in a better prediction of the virtual ballistic range tests than a traditional database. The time-delay network had good open-loop performance but suffered from closed-loop instability.

An improved transfer coefficient method considering the combined effect of reservoir level variation and rainfall and its application in the stability evaluation of multistage sliding ancient landslides

Abstract In this paper, by considering the dynamic water pressure and particle migration effect caused by reservoir level variation, the weakening effect of slip zone soil influenced by rainfall infiltration, and the interaction force between multistage sliding bodies, an improved transfer coefficient method for multistage sliding ancient landslide is proposed under the combined action of reservoir level variation and rainfall. The results show that (1) the combined action of reservoir level variation and rainfall has a significant influence on the stability of multistage sliding ancient landslides. (2) The sliding force calculated by the improved transfer coefficient method is smaller than the calculation result by the traditional transfer coefficient method, and the residual sliding force is larger. The different sliding body stability coefficient is reduced by about 28.84, 18.13, 19.26, and 21.01%, respectively. (3) The stability results calculated by the traditional transfer coefficient are higher than the improved transfer coefficient method, which may lead to deviation in the multistage sliding ancient landslide stable state judgment. (4) This improved transfer coefficient method can provide a reference for the multistage sliding ancient landslides stability accurate evaluation in hydropower station reservoir area.

Knowledge Donating And Its Impact On Collective Intelligence: Sociolinguistic Analytical Study Of Arab Employees At Al-Rajhi Bank

The current research aims to measure the role that knowledge donation plays in collective intelligence, represented by the dimensions. The researcher distributed (125) questionnaires to a sample of Al-Rajhi Bank employees in Riyadh, and (102) analysis forms were adopted. To draw the results, the researcher used Several statistical methods such as normal distribution, Cronbach’s alpha stability coefficient, arithmetic mean, standard deviation, and structural equation modeling. The researcher reached a set of results, including that Al-Rajhi Bank's interest in encouraging its employees to share knowledge among them contributes to developing their collective intelligence by improving their mental abilities to present new creative ideas that serve the interest. Implementing training and development programs: the bank can provide training and development programs for its employees to improve their Arabic language skills and ensure their ability to communicate effectively with customers. In addition, the researcher presented several recommendations, including that Al-Rajhi Bank's keenness to share knowledge requires them to urge employees to participate in training workshops to improve their cognitive and mental abilities—improving the bank's performance in its various branches.