Distribution Law Research Articles

Calculation of Blasting Damage Zone Radius of Different Charge Structures in Burnt Rock

The radius of the failure area after a blasting fracture process of burnt rock is affected by joint fissures, does not conform to the existing theoretical calculation formula and the distribution law of the failure area also changes. The fracture area is large, and the fracture extension and expansion area are small. Therefore, in order to describe the damage of blasting to a fractured rock mass more objectively and accurately, on the basis of summarizing the previous research results, a damage variable was introduced to characterize the initial crushing degree of the fractured rock mass, and the corresponding rock failure criterion was used to derive the calculation formula of a blasting crushing circle and fracture circle radius of burnt rock with different charge structures. The results show that the blasting failure zone of fractured rock mass with different charge structures was not only related to the radius of the blast hole and the explosive and rock properties, but also had a strong relationship with the initial damage degree of the rock mass. Taking an open-pit coal mine in Xinjiang as an example, the radius of the fracture zone with different charge structures was obtained by using the obtained calculation formula, and it was applied to the determination of row spacing and hole spacing.

Simulation study on hydrogen concentration distribution in hydrogen blended natural gas transportation pipeline.

Hydrogen is a clean energy source, and blending it with natural gas in existing pipeline networks is a key transition solution for transportation cost reduction. However, during the transportation process, a non-uniform distribution of hydrogen concentration occurs in the pipeline due to gravity. Therefore, it is necessary to study the hydrogen concentration distribution law of hydrogen-blended natural gas in pipelines. The undulation and ball valve pipelines, which are common in transport pipelines, were constructed in this study. The effects of the undulation angle, height, pipeline diameter, ball valve opening, and temperature on the distribution of the hydrogen concentration were investigated using computational fluid dynamic (CFD) methods. The results indicated that the hydrogen concentration gradient changed gently with the larger diameter of the undulating pipeline, minimizing hydrogen accumulation. Higher undulation angle and smaller height differences reduces the hydrogen accumulation risk. Increasing vertical height difference of the pipeline from 5 m to 15 m increased the hydrogen volume fraction gradient by1.3 times. In the ball valve pipeline, the velocity fluctuation decreased as the ball valve opening increased. However, the hydrogen accumulation phenomenon was obvious. The opening increased from 25% to 100% and the hydrogen volume fraction gradient increased more than two times. Selecting delivery conditions with low hydrogen blending ratios, high temperatures, low pressures, and high flow rates reduces the occurrence of hydrogen buildup in the pipeline.

Studies on the free vibrations of tether of submerged floating tunnel involving tube motion by using different mechanical models

To accurately acquire the frequency/mode of the tethers of the tether-type submerged floating tunnel (SFT), which is an innovative underwater traffic structure with great potential, the dynamic frequency (DF) and wet mode (WM) of the tether involving the tube motion are studied. The novelty lies on the proposed novel method where the analytical relation of the tether’s DF and WM with the moving boundaries and the structural parameters is directly built. The gap that the unreported premise of quasi-static treatment for the global vibratory SFT and the unmentioned principle of the top tension of the tether equaling the net buoyancy within its supporting range is filled. Firstly, four mechanical models named M1∼M4 are respectively established by equating the tether as a beam or string with moving boundaries, taking into accounts the bending stiffness, wet-weight and other geometrical/material factors. Secondly, the relationships between the band-width, upper/lower limits of the DF and the inclination angle, vertical height, buoyancy-weight-ratio (BWR), motion amplitude are founded. Thirdly, the distribution laws of the DF during the vertical periodic motion of tube, as well as the parameter sensitivity range of the WM to the span-wise effect of wet-weight and the vertical height, are studied. The results show that the tether exhibits DF under the tube motion. The band-width of DF is sensitive to the BWR, inclination angle, vertical height and motion amplitude, and its upper/lower limits exhibit varying degrees of variation patterns with the changing of these parameters. The wet-weight and the vertical height are two main influencing factors of the WM. The proposed method provides a new treatment idea for further in-depth research on the locking zone of the vortex-induced vibration (VIV) and parametric vibration for the tether of SFT.

Violation of Exclusive Distribution Agreement: Case Study of PT Unilever Indonesia Tbk vs PT Indomarco Prismatama

Breach of exclusive distribution agreement is one of the critical issues that often arise in business relationships between manufacturers and distributors, especially in competitive industries such as fast-moving consumer goods. The case involving PT Unilever Indonesia Tbk and PT Indomarco Prismatama (Indomaret) is a clear example of such a dispute, where the dispute arose from an alleged breach of an exclusive distribution agreement by Indomaret. Unilever claimed that Indomaret, acting as one of their main distributors, had sold Unilever's products outside the terms stipulated in the exclusive agreement, including selling the products below the agreed price or even to third parties not included in the authorized distribution network. This study examines in depth the legal aspects of exclusive distribution agreements in the context of business disputes in Indonesia, with a focus on the Supreme Court's decision number 1559 K/Pdt/2015 which upheld Unilever's claim for breach of contract by Indomaret. Through normative juridical analysis, this research seeks to explore the implications of the ruling for product distribution practices in Indonesia, as well as how such breaches may affect the long-term business relationship between manufacturers and distributors. The analysis shows that exclusive distribution agreements are contractual instruments that have a significant impact on competition in the market. When one party breaches the agreed terms, whether in terms of price, distribution area, or other requirements, the impact is not only limited to legal aspects, but also touches on aspects of reputation and business relationships. In this case, the Supreme Court ruled that PT Indomarco Prismatama was guilty of breach of contract and was required to compensate PT Unilever Indonesia Tbk. This judgment emphasizes the importance of compliance with exclusive distribution contracts and the need for strict sanctions to maintain market integrity. The broader impact of this breach also includes aspects of fair competition. This research highlights how non-compliant distribution practices can affect market dynamics, especially when large distributors such as Indomaret are involved. Under these conditions, exclusive distribution violations can create unfair conditions for other business actors who operate in accordance with existing rules. Therefore, in addition to the legal implications of breach of contract, this study also proposes stricter regulations and effective monitoring mechanisms to prevent such practices from occurring in the future. In addition, this study also provides insights into how the business relationship between producers and distributors should be maintained through a clear and transparent contractual mechanism. One of the key findings of this research is the importance of detailed agreements and strict sanctions against violations, as well as the need for close supervision of contract implementation, especially in highly competitive industries. This applies not only to the consumer goods sector, but also to other sectors that rely on extensive and complex distribution systems. Thus, this research contributes to the understanding of the importance of exclusive distribution agreements in maintaining a balance between the business interests of producers and distributors, as well as in ensuring the creation of a competitive and fair business climate. This research also enriches the literature on business and distribution law in Indonesia, and provides practical insights for companies involved in distribution agreements to avoid potential disputes in the future.

The Influence of Non-Pressure Pipes Filled to Different Degrees on the Hydraulic Characteristics of Channel–Pipe Combined Irrigation Systems

Modern irrigation areas often use a combination of channels and pipes for irrigation. Due to changes in terrain, inflow, and pipe diameter, pipelines are often prone to experiencing a state of no pressure. This lack of pressure affects not only the velocity distribution and water surface profile of the main channel but also the velocity distribution and flow distribution of the pipeline. Therefore, in this study, we employed a combination of physical model experiments and theoretical analysis to study the influence of non-pressure pipelines on the hydraulic characteristics of channel–pipe combined irrigation systems filled to different degrees. Through this, the variation laws of the flow velocity distribution, turbulence intensity, water surface, diversion width, and diversion ratio under different filling degrees were obtained. The non-pressure pipeline flow velocity expression was obtained through dimensional analysis, and the calculation formula for the non-pressure pipeline flow velocity coefficient was fitted using linear regression analysis. The relative error between the calculated value and the measured value did not exceed 8.81%. The research results presented in this article can provide technical support for the design and maintenance of channel–pipe combined irrigation systems.

Numerical Simulation of the Distribution Patterns of Particle Deposition on the Vertical Wall Behind Near-Wall Heat Source

Near-wall heat sources have a crucial part to play in the process of particle deposition. Thus, this study investigates the impact of the near-wall heat source on the distribution patterns of particle deposition on the vertical wall behind the heat source, taking into account the variability in heat source temperatures and distances from the vertical wall. A model based on the Eulerian–Lagrangian method was established for tracking the motion trajectories of 1000 particles with a density of 1400 kg/m3 and a particle size range of 0.01–10.0 μm. The temperature field, airflow field, and particle deposition distribution in six cases were analyzed. It was shown that the heat source temperature significantly affectis the temperature field, airflow field, and particle deposition distribution on the vertical wall behind the heat source. This study demonstrated that as the temperature rises, the quantity of particles deposited in the upper-right region of the vertical wall decreases more noticeably. The quantity of particles deposited onto the vertical wall is inversely related to the distance between the near-wall heat source and the vertical wall. On one hand, the deposition distribution law serves as a foundation for advancing the technology aimed at removing suspended particles via thermal plumes. On the other hand, it provides critical insights for addressing the challenges associated with harmful particle deposition linked to the attachment effects of thermal plumes.

Experimental study on fire characteristics of urban rectangular tunnels based on different slopes

Abstract To explore the combustion pattern and temperature distribution law of urban rectangular tunnels when a fire occurs. Considering the influence of variables such as different firepower, fire source spacing, and tunnel slope, the vertical and horizontal flame combustion patterns and tunnel temperature distribution of double fire sources under different slopes were studied by the indoor model experiment method. The results show that under the same conditions of the fire source spacing ratio μ, when the slope of a rectangular tunnel is between 0% and 3%, the influence of dual flames combustion morphology on tunnel slope is relatively small; When the tunnel slope is 4% to 5%, that has a significant impact on the combustion morphology of dual flames, and the flames are more dispersed and sparse than the tunnel slope is between 0% and 3%. As the tunnel slope increases, a high-temperature zone forms at the top of the tunnel and gradually moves towards the uphill direction of the tunnel, the high-temperature area gradually decreases as the slope increases with the same μ. The research results provide a theoretical basis for the fire protection design standards and fire prevention measures of urban rectangular tunnels.

Study and mechanism analysis on fracture mechanical properties of steel fiber reinforced recycled concrete (SF-R-RC)

Recycled concrete has deficiencies in its overall performance due to the deteriorated properties of the recycled aggregate (RA) used. Based on the RA characteristics and fiber reinforcement mechanism, designing recycled concrete by adding steel fiber (SF) and enhancing RAs in a coordinated manner can effectively improve the overall performance of recycled concrete. Therefore, this paper considers the SF content and RA enhancement to study the fracture mechanical properties of steel fiber reinforced recycled concrete (SF-R-RC), and the main conclusions are as follows: the fracture mechanical properties of SF-R-RC are significantly affected by aggregate enhancement and SF content. Without the SFs, the strengthened coated recycled aggregate concrete (CRAC) was better than unreinforced recycled aggregate concrete (RAC) in terms of the unstable fracture load, fracture energy, initial fracture toughness and unstable fracture toughness, but weaker than normal aggregate concrete (NAC). The increase in the unstable fracture load, fracture energy, initial fracture toughness and unstable fracture toughness of NAC, RAC and CRAC with the increase in SF content was observed, with CRAC showing the most significant increase in these fracture parameters. Applying digital image correlation (DIC) and acoustic emission (AE) techniques, the effect of SF content and RA enhancement method on the crack evolution process and damage distribution law of SF-R-RC was studied. Meanwhile, the microscopic testing technique was used to reveal the mechanism of the influence of SF and RA enhancement on the fracture mechanical properties of SF-R-RC. The research results of this paper provide a theoretical basis for the application of RA enhancement and SF reinforcement methods of recycled concrete in practical engineering.

Assessing the impact of marine growth on the structural integrity of jacket platforms

ABSTRACT The marine organisms of the jacket platform will directly affect the surface roughness and hydrodynamic coefficient of the platform. Therefore, it is of great significance to effectively analyze the influence of the attachment of marine growth on the structural performance of the platform. Firstly, the distribution law of marine growth was established by the statistical data in Bohai Sea of China. Secondly, the hydrodynamic coefficients of the platform which were changed due to marine growth were determined, and the finite element model of the platform was established. Finally, the finite element simulation results of the platforms with attachment patterns of no marine growth, uniform marine growth, and non-uniform marine growth respectively were compared. It is shown that the calculation results of the platform with uniform marine growth were relatively conservative. Meanwhile, the attachment of marine biofouling produced a significant effect on the structural hydrodynamic load, etc. of the platform.

Fisher-Tippet Law Truncated Form for Loading Modeling of Machinery Structures

Introduction. Statistical data are used as a basis for assessing the reliability of engineering structures. However, incomplete data or inaccurate modeling of random variables may lead to an overestimation of reliability indicators. In practice, laws with infinitely decreasing or increasing distribution functions of an exponential family are usually used to model random variables characterizing the bearing capacity, load, and resource of engineering structures. To improve the accuracy of modeling of random variables, truncated forms of distribution laws are often used. These forms allow us to consider the random variable within a specified interval, excluding impossible values. Several studies have suggested using the Fisher-Tippett law with three parameters for modeling random variables related to the loading of engineering structures. The advantage of this law is that it limits the range of the random variable on the right side, but the left side of the distribution function decreases indefinitely, which is not ideal for load characteristics. To improve the accuracy of predicting random variables that characterize the load, it would be helpful to have a left-sided restriction using the Fisher-Tippett law. Currently, there are no descriptions of truncated forms of the distribution law in scientific literature. This article will explore the justification and development of a three-parameter truncated form of the Fisher-Tippett law and its use in calculation methods. The goal is to create a left-sided truncated version of the Fisher-Tippett distribution with three parameters to model random variables within a specific range.Materials and Methods. The article provides a detailed description of the history of the Fisher-Tippet law, including its three-parameter form, and justifies the need for obtaining its truncated form.Results. As a result of the research, a truncated form of the Fisher-Tippet three-parameter law in differential and integral forms was obtained and substantiated. The findings included graphs and calculations that demonstrated the normalization of a random variable within a given range.Discussion and Conclusion. The conclusion was drawn about the advantages and disadvantages of the truncated form of the Fisher-Tippet law. The possibility of its practical application in the schematization of random loading processes under operating conditions and testing of machine elements and structures to assess fatigue life and determine fatigue resistance characteristics was established. The direction of further research is related to the practical use of the truncated form, particularly with the need to develop a method for evaluating the parameters of the truncated distribution and verifying the consistency of the proposed model

LEVERAGING LOTUS SEEDS’ DISTRIBUTION PATTERNS FOR FRACTAL SUPER-ROPE OPTIMIZATION

The seeds within a lotus seedpod are distributed in an orderly fashion and safeguarded within a secure packaging system. The distribution law is thus revealed, and the packaging mechanism can be emulated for contemporary applications. This paper presents a novel and ingenious method for optimizing fractal super-ropes, inspired by the captivating distribution patterns observed in lotus seeds. The distinctive configuration of the lotus seed represents a model of natural optimization, offering insights that can enhance the exceptional performance and multifaceted functionality of super-ropes utilized in the construction of formidable aircraft carriers, elegantly designed cable-stayed bridges, and stab, bulletproof fabrics. The lotus seedpod provides the fundamental structural framework upon which super-ropes with a sophisticated hierarchical configuration are meticulously constructed. The five super-ropes are presented for detailed examination, offering a promising avenue for further investigation. This paper presents a novel geometrical approach to the optimal design of super-ropes, thereby establishing a promising foundation for extensive future research.

MODERN METHODS OF QUANTITATIVE ASSESSMENT OF THE STRUCTURE OF HYDROCARBON RESOURCES OF LARGE PETROLEUM BASINS

The article discusses modern methods of quantitative assessment of the elements of hydrocarbon resource structure in large oil and gas (petroleum) basins. The assessment is based on the law of mass distribution of hydrocarbon accumulations, i.e., the truncated Pareto distribution. The procedure developed is used for: estimation of the truncated Pareto distribution parameters and cumulative hydrocarbon volumes concentrated in pools, prediction of their number and size distribution and total resources within each size-class interval; simulation of spatial distributions of hydrocarbon accumulations with transformation of a population of HC pools into a population of fields; prediction of the number and size-class distribution of total HC resources in pools and fields, and fields distribution by the number of HC pools. The involved analytical approach based on the simulation mathematical modeling is described.

Investigation on the safety of 30,000-ton combined train with different lag times of slave control locomotives

To investigate the influence of the lag time in braking response of the slave control locomotives caused by the LOCOTROL wireless synchronous control system on the longitudinal impulse of the train, a 30,000-ton heavy-haul train model was established. The model is in the form of ‘1+1+1+1’. The simulation accuracy of the air braking system was verified by comparing with static tests. A dynamic model consisting of two HXD1 locomotives and a 100-type couple was established for study the middle locomotive’s running safety. Results show that, under normal transmission delays, the lag time in the braking response of the slave control locomotives is approximately 2–3 s. The lag time significantly influence the coupler force and its distribution law. During emergency braking, the lag time increased from 0 s to 6 s, and the maximum coupler force increased by 1877.1 kN. Among the three slave control locomotives, the one positioned in the middle has the greatest impact on the coupler force, while the one closest to the leading locomotive has the least impact. When the lag time reaches 5 s, the middle locomotive’s coupler becomes unstable. Increasing the lateral stiffness of the secondary suspension is beneficial for enhancing the locomotive's ability to stabilise the coupler.

Features of damage to the central nervous system and mental sphere in patients with comorbid post-COVID syndrome

The prevalence of post-COVID syndrome in patients treated on an outpatient basis ranges from 10 to 35 %; it can reach 80 % in patients with severe coronavirus infection. It is currently hypothesized that long-COVID may be due to both the direct effects of the SARS-CoV-2 virus and the biopsychosocial effects of COVID-19.The aim. To study the characteristics of damage to the central nervous system and mental sphere in patients with comorbid post-COVID syndrome.Materials and methods. To study the clinical features of the course of post-COVID syndrome, 98 patients who had suffered COVID-19 were examined. Of these, 18 (18.4 %) were men, 80 (81.6 %) were women. The mean age in the group was 56.05 ± 1.27 years. The examination program included a questionnaire, clinical examination, pulse oximetry, and assessment of exercise tolerance using the Borg scale. Statistical processing was carried out using the Statistica software package, version 6 (StatSoft Inc., USA). The results of the study are presented as a median, upper and lower quartiles. After analyzing the compliance of the studied indicators with the law of normal distribution (Shapiro – Wilk test), the groups were compared using the Wilcoxon test for pairwise comparison of related samples. Differences were considered statistically significant at p < 0.05.Results. Our studies of comorbidity and complications after COVID-19 infection revealed the most frequent involvement of three systems in the pathological process: cardiovascular, nervous and endocrine. Metabolic syndrome was detected in 67 % and involvement of the cardiovascular system was detected in 48.8 % of those examined.One of the main manifestations of post-COVID syndrome is damage to the central nervous system and mental sphere in the form of mild cognitive and emotional-volitional disorders with asthenodepressive and anxiety-depressive disorders.Conclusion. The health status of patients after COVID-19 is significantly lower than that of the general population. The study results indicate an urgent need to study the pathogenesis of long COVID and develop effective interventions to reduce the risk of its development.

Study on dynamic response distribution of excavated highway slope under dynamic action

In order to study the dynamic response distribution law of highway foundation pit slope under seismic dynamics, the dynamic response distribution law of cutting slope at different grading heights was compared and studied, and the dynamic instability model under gravity instability and seismic disturbance was established by using UDEC700 software, and the simulation calculation was carried out. The difference between static instability and dynamic instability of fractured rock slope is compared and analyzed, and the post-earthquake stress is greater than that before the earthquake. Under the action of power, the velocity at the top of the slope is greater than the velocity at the bottom of the slope, the velocity outside the upper platform is greater than the velocity inside, and the velocity inside the lower platform is greater than the velocity outside. This provides a new perspective for understanding the dynamic response of highway foundation pit slope under seismic dynamics.

Study on the influence of advancing speed on the dynamic distribution laws of spontaneous combustion hazard zones and high-temperature points in goaf areas

Spontaneous combustion of coal occurs when arising from a combination of factors, including oxidation and heating of residual coal in goaf and favorable heat retention conditions, and the spontaneous combustion hazard zones and high-temperature points formed exhibit dynamic, concealed, and three-dimensional characteristics, further complicating the on-site prevention and control of coal spontaneous combustion. Therefore, it is particularly important to study the dynamic evolution of coal spontaneous combustion (CSC) hazard areas in the goaf during the working face advancement process. With 010803 working face of Wang Wa Coal Mine for reference, the paper develops a three-dimensional Multiphysics coupling model of the goaf through field tests, laboratory experiments, and numerical simulations. For the first time, three-dimensional dynamic mesh technology is employed to investigate the spatial dynamic variation laws of spontaneous combustion hazard zones in goaf areas under advancing speeds ranging from 2 to 8 m/day. The results indicate that the relative error between simulated leakage airflow and field measurements is 1.4 %. As the advancing speed of the working face increases, the oxidation zone in the goaf shifts deeper, and its area increases linearly, though the rate of increase gradually decreases. With higher advancing speeds, the temperature of the high-temperature points in the goaf decreases, and the distances of these points from the lower corner of the working face grow exponentially in both strike and dip directions. However, the high-temperature points remain within the oxidation zone, with their strike migration ranging from 86.3 to 149 m and dip migration from 44 to 51 m. Based on this analysis, a spatial distribution function for high-temperature points in goaf areas is proposed. This study provides theoretical support for preventing and controlling coal spontaneous combustion in goaf areas.

Simulation analysis of detonation wave propagation in explosive with multiple initiation points by generalized Interpolation material point method

In the research of explosion shock theory and engineering application, the convergence of detonation waves can be realized by using multiple initiation points to utilize the detonation energy and pressure effectively. To study the propagation process of detonation wave and the distribution law of impact energy of the explosive with multiple initiation points, a detonation calculation model of the explosive with multiple initiation points is constructed using an improved material point method, namely the generalized interpolation material point (GIMP) method. Meanwhile, two-dimensional and three-dimensional numerical simulations are given on detonation wave propagation and convergence processes in explosives with multiple initiation points. The process of detonation wave formation and convergence is simulated by Wuji Particle Dynamics (WP-DYNA) software, and the dynamic changes of physical parameters such as detonation pressure, product density, and internal energy are analyzed in detail. To verify the accuracy of numerical simulation, corresponding explosive detonation experiments are carried out; the simulation results are compared with the ultra-high speed photoelectric framing photography and the aluminum ingot double detonating cord experiment. The results show that the generalized interpolation material point method has good stability and relatively high calculation accuracy when simulating explosive detonation waves. A robust numerical calculation tool can be provided for the practical application of explosive detonation.

Distribution law analysis and calculating method for windage power in a geotechnical centrifuge

Distribution law analysis and calculating method for windage power in a geotechnical centrifuge

Failure characteristics and stress field distribution law of roadway in downward mining of deep close distance coal seam

Deep close distance coal seam mining is affected by the goaf of upper coal and remaining coal pillar, and the roadway of lower coal is difficult to maintain stability. By means of theoretical analysis, physical simulation test and numerical simulation, this paper analyzes the failure characteristics of roadway in deep close distance coal seam and the evolution law of stress field, and optimizes the reasonable layout of lower coal roadway. The results show that: (1) The analytical formula of the evolution of the floor principal stress difference with depth is derived theoretically, and the distribution law of the shear stress of the rock mass in the floor of the coal seam is obtained. (2) The airway below the goaf can maintain good stability. High stress accumulation phenomenon occurs in the transport roadway below the coal pillar, which can not keep stable. (3) Due to the stress difference under the goaf and the coal pillar, the shear stress increases and the rock mass is damaged, and the left gang of the transport roadway is prone to instability destruction. (4) By comparing the distribution characteristics of plastic zones of transport roadway at different locations, it is determined that the transport roadway is more appropriate to be arranged 45 m below the coal pillar from the goaf.

Experimental study on the interfacial bond behavior of UHPC filled circular stainless steel tubes

As the interfacial bond property is of great significance to derive the composite action between stainless steel tube and UHPC for the Ultra-High Performance Concrete Filled Stainless Steel Tubular (UHPCFSST) columns, the push-out tests were conducted in this program, which includes 8 specimens having different stainless steel tube diameter and tube thickness. Based on the test results, the damage patterns and the full range load-slip curves are analyzed in detail, and the interfacial bond stress constitutes at different loading stages were also identified and evaluated. On top of that, the longitudinal strain of the stainless steel tube was analyzed based on elastic theory to derive the non-dimensional bond stress distribution law along the steel-concrete interface. The comparison between test results and the predictions from current code specification or the available empirical formulas indicate a large discrepancy and inconsistency. Therefore, the bond strength and corresponding slippage value of UHPCFSST columns were predicted by a new equation based on regression analysis. The research discovery obtained from this study provides theoretical significance and practical value for improving the design theory and application of UHPCFSST columns in practical engineering.