Investigating the effects of effective stress on pore-dependent permeability measurements of crushed coal

The accurate determination of permeability is one of the parameters essential for the study of fluid flow and transport state. However, a large number of fractured coal bodies are faced during the production of coal mines. The study of permeability of these special media composed of grains of a certain size, whose structure is different from that of raw coal, has been in the exploratory stage. In this paper, inspired by the calculation method of median particle size and the calculation principle of KC’s equation, we calculate the permeability parameters of broken coal particles. It is considered that its permeability is closely related to the compaction and re-crushing process of skeletal grains. The lateral limit compression test of the crushed coal body was designed, and the pore-dominated permeability calculation method was given to reveal the mechanism of the action of the effective stress. The dependence relationship between the effective stress and the pore-correlation permeability is obtained by data analysis, and the force and deformation process of the crushed coal grain media is described. In contrast to the conventional Darcy series of permeability discussions, our approach excludes the influence of fluid factors on the permeability of porous media. The permeability of porous media is considered to be determined only by its own pore structure.

LDA-CBOW-Based Mining Model for Risky Driving Behavior in Traffic Accidents

Traffic accident data of traffic management department is recorded in unstructured text form, which contains a large number of characteristic descriptions related to risky driving behavior. However, such data has short text length and abundant professional vocabulary. Many text mining techniques cannot effectively analyze such text data. This paper proposes an improved LDA algorithm based on CBOW—LDA-CBOW model for the study of traffic accident text data containing illegal behaviors. This model can better extract the topics of traffic accident data and filter the keywords under the corresponding topics, which provides a better way to study the dependence relationship between traffic data and illegal behaviors. Experiments show that compared to other models, this model can better extract related topics of traffic accident data with higher model efficiency and better robustness.

Cloisite 20A Based Polyaniline Nanocomposites for Nitrogen Dioxide (No2) Gas Sensors

Compacted polyaniline (PANI)/Layered silicate nanocomposites have been successfully prepared by simple in situ, core-shell, and ex situ polymerization routes using AnHCl as a predecessor through chemical oxidation method. The structure, chemical groups, electronic transition and properties were investigated by XRD, SEM, HRTEM, UV Visible, DC electrical conductivity, TGA, and DSC. The XRD results reveals that HCl-treated Cloisite 20A, and PANI-ES/Cloisite 20A nanocomposites are delaminated. Flake-like morphologies were observed in Cloisite 20A and HCl-treated Cloisite 20A, whereas different rate of compacted fibrous morphologies of prepared PANI-ES/Cloisite 20A nanocomposites were observed as evident from SEM images. The Si-O FTIR band position does not change even after HCl treatment of Cloisite 20A, but different FTIR peaks positions of PANI-ES/Cloisite 20A nanocomposites were shifted from pure PANI-ES peaks after using Cloisite 20A nanoclays. UV-Visible spectra indicated the increment of charge carrier within the PANI-ES/Cloisite 20A nanocomposites compared to the pure one. The prepared nanohybrids showed significantly improved thermal property compared to pristine PANI-ES as clear from TGA and DSC analysis. The highest DC electronic conductivity of nanocomposite prepared by core-shell route is found to be 5.12 S/cm using linear four probe techniques. In addition, the charge transport mechanism was understood with and without loading Cloisite 20A in PANI-ES. The conductivity data supported the temperature-dependence relationship σ(T) = σ0.exp[-To/T)1/4] and followed characteristic of three-dimensional variable-range hopping (3D‒VRH) mechanism. In addition, we were discussed the response of Nitrogen dioxide (NO2) gas with polyaniline based sensor materials.

Experimental and Numerical Analysis of the Depth of the Strengthened Layer on Shafts Resulting from Roller Burnishing with Roller Braking Moment

The article presents the results of investigations into the depth of the plastically deformed surface layer in the roller burnishing process. The investigation was carried out in order to obtain information on the dependence relationship between the depth of plastic deformation, the pressure on the roller and the braking torque. The research was carried out according to the original method developed by the authors, in which the depth of plastic deformation is increased by applying a braking torque to the burnishing roller. In this method, it is possible to significantly increase (up to 20%) the depth of plastic deformation of the surface layer. The tests were carried out on a specially designed device on which the braking torque can be set and the force of the rolling resistance of the roller during burnishing can be measured. The tests were carried out on specimens made of C45 heat-treatable carbon steel. The dependence of the depth of the plastically deformed surface layer was determined for a given pressure force and variable braking moments. The depth of the plastically deformed layer was measured on the deformed end face of the ring-shaped samples. The microhardness in the sample cross-section and the evolution of the microstructure were both analysed.

Factors Affecting the Trade Dependence Relationship of Asian Countries with China: Implications for China’s Belt and Road Initiative

China’s Belt and Road Initiative (B&R) has received much doubts about its impact on Asian countries. This paper studies the B&R effect from a new perspective of the trade dependence relationship, and explores this B&R impact on the influencing factors of the degree of trade dependence. By implementing a series of grouping analyses on influencing factors, this paper analyses the impact of four national characteristics, including Asian countries’ income levels, geographical location characteristics, social development levels and intimacy with China, and finally gives a robust test by combining alternative indicators of trade dependence degree based on information entropy. The empirical results show that trade dependence degree has increased after implementing the B&R, but its downward growth rate shows that the B&R has not taken over the trade dependence. The inhibiting effects of energy exports on the degree of trade dependence deny the trade binding hypothesis due to the increasing energy of export trade. Trade openness and infrastructure development had a negative effect on the degree of trade dependence, while their cross-product term weakened their respective inhibitory effects, and even more after B&R. Meanwhile, the asymmetry of trade and FDI have a significantly positive impact on the degree of trade dependence. Moreover, grouping national characteristics will bring the promoting or inhibiting effects of these influencing factors on the degree of trade dependence. The robust test presents conclusions. This paper enriches the research content on the B&R, and the findings can provide some implications on the selection of trade partners and the sustainable development of the B&R.

Extractive Latifundio and the Low Income of the Extractive Reserve Rio Ouro Preto, Western Amazon

In an attempt to mitigate the environmental impacts caused by large farmers, extractive reserves (RESEXs) were founded with the objectives of conserving biological diversity and meeting traditional communities’ vital needs. This study aimed to evaluate whether the objectives of human needs satisfaction and environmental conservation were achieved based on institutional investments in a RESEX in the Brazilian Amazon. The study was developed through the association method, and we confirmed interference due to the dependence relationship that occurred between the variables of the economic and social groups with the institutional one. Here, we conclude that low investments in social (education and health) and productive policies (roads, transport, and technical assistance) prevent social development and consequently motivate deforestation when families seek to ensure subsistence.

MANAGEMENT MODEL WITH PROCESSES TO IDENTIFY SEISMIC VULNERABILITY IN HOUSING

Seismic events for decades have caused great prejudice to countries causing human and economic losses due to the collapse of houses, therefore the relevance of this research lies in offering a management model with processes to identify the seismic vulnerabilities of houses and validate the correlation between whether there is dependence between the Knowledge of the Management Model with Processes and its application (hypothesis). A mixed method (quantitative and qualitative) is presented, generating reliable and concise results, issuing Chi-Square values to prove that they are greater than 0.05, implying a very weak or low dependence relationship. Consequently, it is concluded with a confidence level of 95%, indicating the way in which the knowledge of the model is developed and its application, has very little dependence in the local governments of the Moquegua Region, since they do not know the proposed model.

Research on the Dependence Structure and Risk Spillover of Internet Money Funds Based on C-Vine Copula and Time-Varying t-Copula

Internet money funds (IMFs) are the most widely involved products in the Internet financial products market. This research utilized the C-vine copula model to study the risk dependence structure of IMFs and then introduces the time-varying t-copula model to analyze the risk spillover of diverse IMFs. The results show the following: (1) The risks of Internet-based IMFs, bank-based IMFs, and fund-based IMFs have obvious dependence structure, and the degree of risk dependence among different categories of IMFs is significantly different. (2) There are risk spillover effects among diverse IMFs, and their risk dependence relationship is characterized by cyclical feature. (3) The risk spillover effect among diverse IMFs is pronounced, and dynamic risk dependence between IMFs is characterized by synchronization.

Modeling resilient factors of the supply chain

Purpose This paper aims to study the concept, characteristics and factors of the resilient supply chain (RSC) and develop a hierarchical structural model and classify the factors based on their interrelationships. Design/methodology/approach This paper has used a mixed-approach of literature review and expert opinion to identify the factors of RSC. For the development of the structural model and clustering of the factors, this paper has used the total interpretive structural modeling approach with Matrice d’Impacts Croises-Multiplication Applique and Classment and decision-making trial and evaluation laboratory analysis. Findings In total, this study has identified 17 factors that enable the 3R capability of the RSC. The result shows that the factors have a close dependence relationship with supply chain (SC) risk management culture as the most influencing factor. Further, this study classifies the factors into enablers and strategies. Research limitations/implications This research work is the theoretical contribution to the RSC concept and helps the experts to develop and improve the resilient ability in the SC. This research is based entirely on subjective expert feedback; thus, the results are sensitive to the expert’s judgment. Practical implications This research will help the decision-makers in allocating the resources and policies to develop or improve the SC capabilities. Originality/value This research work is the first kind of research in the field of the RSC that considers the 3R concept to identify and model the resilient factors of the SC. Along with the theoretical concept, this research provides empirical evidence for the importance ranking of the factors.

Re-crushing process and non-Darcian seepage characteristics of broken coal medium in coal mine water inrush

The initiation process of the mine water inrush accident, the essence of this process is the sudden change of the seepage state of the broken coal medium under pressure and the instability of the skeleton. In order to study the re-crushing mechanism and seepage characteristics of the broken coal medium under load, a set of three-axis seepage system was designed independently. Using the steady-state infiltration method, multiple flow factors under different particle size combinations and different stress conditions of the broken coal medium were obtained. The results of the study indicate: in one hand, the reduction of the porosity of the broken coal medium will cause the flow channel to be rebuilt, and the sudden change of flow rate will directly lead to the non-Darcian flow behavior. The early stage of compaction mainly affects the permeability k value, and the later stage of compaction mainly affects the non-Darcian β value; On the other hand, the seepage throat in the broken coal medium may have a sharp increase in its flow rate, leading to a sudden change in the flow pattern. The critical Reynolds number is also used to determine whether non-Darcian flow is formed, and its value in the water inrush system is about 40–133; at the same time, the non-Darcian flow in the broken coal medium conforms to the Forchheimer-type flow law. By analyzing the dependence relationship between factors, a seepage factor representation algebraic relationship suitable for Forchheimer type non-Darcian flow of broken coal medium is given, which can be used as a calculation basis in the prevention and treatment of mine water inrush accidents.