Engineering Background Research Articles

Study on the safety distance determination model for natural gas wells in Ordos Basin subsidence areas of coal mining

To optimize the safe distance between coal mining faces and natural gas wells, with the Ordos Basin as the engineering background for the intersectional development of natural gas and coal resources, a Gaussian function equation for subsidence curves under complete mining was proposed based on the probability integral method, and a model was constructed to determine the coordinated mining safety distance between coal mining faces and natural gas wells. Based on the distributed optical fiber monitoring principle of the BOTDR technology, on-site monitoring of the simulated monitoring well GX1 within the safety distance was carried out. The results indicated that the maximum strain change values of the outer casing and inner production casing of the simulated monitoring well GX1 were 836 με and 766 με, respectively, far less than the maximum ultimate tensile strain value of the overlying rock at the same depth position. Furthermore, the casing structure possessed ample resistance capability, ensuring no noticeable deformation occurred. Through comparison, it was found that the discriminant model reduced the reserved safety distance between the coal mining working face and the natural gas well by 58% compared with the currently used avoidance method of the surface subsidence boundary, liberated coal resources, and achieved a "win–win" situation of the coordinated mining of natural gas resources and coal resources. It can reasonably adjust the coordinated mining problem without a natural gas-coal co-mining mechanism, provide a new method for the layout of natural gas wells in gas-coal overlapping areas, and provide new ideas for the coordinated mining of coal-related associated resources.

Study on vortex-induced vibration response of large-scale two-lay steel trusses bridge under large wind angle of attack

With the advancement of urbanization, two-lay trusses bridges are widely used because of their good traffic capacity and structural performance. However, the aerodynamic behavior of this beam type is still in the exploratory stage. The local microclimate characteristics at the bridge site in mountainous cities are obvious, and it is easy to form a large wind angle of attack, which has a significant impact on the vortex-induced vibration (VIV) performance of the bridge. Therefore, this study takes a long-span two-lay steel trusses bridge in a mountainous city as the engineering background, and uses wind tunnel test and numerical calculation methods to study the changes of the static three-component force coefficient and VIV response of the main beam in the construction and completion state under the action of high wind angle of attack. The results show that the three-component force coefficient curves under different wind speeds are close to each other, and the Reynolds number effect is not obvious. The vibration test shows that the vertical bending VIV first occurs at +3° and +5°, and then two torsional VIV with different amplitudes occur. Both vertical bending and torsional VIV are simple harmonic vibrations with a single frequency, and the vertical bending VIV frequency is locked at 2.227 Hz, and the torsional VIV frequency is locked at 4.289 Hz, which are close to the natural frequency of the test model. Compared with +3°, the maximum amplitude of vertical bending VIV under +5° increases by 30.0 %, while the maximum amplitude of torsional VIV under high and low wind speed increases by 16.6 % and 12.7 % respectively, and the locking range is longer. It can be seen that the wind angle of attack has a significant effect on the VIV response of the main beam in the completion state. Especially, the trusses beam at a large angle is more sensitive to VIV, and it is more prone to large-scale and large-amplitude VIV. The research results can provide a theoretical basis for the aerodynamic shape optimization and provide a reference for the design of related bridges.

Impact of Retention Agents on Functional Properties of Recycled Paper in Sustainable Manufacturing

The proper dosing and optimization of retention additives are necessary to ensure the desired benefits without compromising other aspects of the paper manufacturing process. In this study, the effects of a cationic polyelectrolyte based on acrylamide and a cationic derivative of acrylic acid on the different properties of paper containing recycled fibers were investigated. The structural and tensile properties were examined through various analyses to determine the optimal dosage of the retention additive. The results obtained indicate that while the retention agent can enhance papermaking efficiency by improving retention, drainage, and sheet formation, it also negatively impacts the tensile strength and surface smoothness of the recycled paper. This complexity highlights the importance of a balanced approach in optimizing retention aid dosages. Determining the optimum dosage of such an agent requires multiple trials and analyses with varying dosages. This review aims to offer a background for engineers seeking to enhance the competitiveness and reduce production costs of their paper products, as well as for researchers striving to surpass the existing standards and achieve innovative outcomes.

The Cycle of Fear in Learning a Foreign Language that Leads to Motivation

Motivation is crucial in foreign language studies to ensure a good understanding of the subject matter. However, the fear of learning a foreign language will affect students’ motivation to learn, ultimately affecting their determination to master a foreign language. This research investigates the perception regarding the motivation and fear of learning a foreign language among pre-university students. A three-section quantitative survey was conducted involving 151 respondents who were recruited via simple random sampling from pre-university students in a Malaysian public university with science and engineering backgrounds. The results revealed that motivation, communication apprehension, fear of negative evaluation, and test anxiety varied from moderate to high. Furthermore, significant associations were found between communication apprehension with fear of negative evaluation and fear of negative evaluation with test anxiety. The findings offer pedagogical implications and suggestions for future research.

Quality Evaluation of Software Engineering Professional Talent Training under the Background of New Engineering

Quality Evaluation of Software Engineering Professional Talent Training under the Background of New Engineering

Exploration and Practice of Talent Training System for the Major of Marine Resource Development Technology under the Background of New Engineering

Exploration and Practice of Talent Training System for the Major of Marine Resource Development Technology under the Background of New Engineering

Research on the Innovation of "Advanced Mathematics" Blended Teaching Based on Knowledge Graph in the Context of New Engineering

Based on the analysis of the relation between the knowledge of higher mathematics and the characteristics of the mixed teaching mode, this paper discusses the innovation of the mixed teaching mode of "higher mathematics" under the background of new engineering, and puts forward the innovation strategy of the mixed teaching mode of "higher mathematics" under the background of new engineering, including optimizing teaching resources, reforming teaching methods, innovating course modules and promoting interdisciplinary cooperation. The research finds that the innovation of "higher mathematics" mixed teaching mode based on knowledge graph is helpful to improve the teaching effect, stimulate students' thinking on mathematical problems, cultivate students' innovative thinking and mathematical modeling ability, and lay a solid foundation for the cultivation of new engineering talents.

Study on the Full‐Cycle Stress Evolution Law and Reasonable Size of Isolated Coal Pillar

ABSTRACTTo study the stress distribution law under different mining times and spaces of the protected coal pillar in the isolated working face, this paper takes a coal mine in Shanxi as the engineering background and adopts numerical simulation and theoretical analysis to obtain the stress distribution law of protecting coal pillar in the isolated working face during the tunneling period and the mining period of the working face, and proves the reasonable size of protecting coal pillar. The results show that the vertical stress and maximum principal stress increase correspondingly with the decrease of the protective coal pillar size under both stages, and the minimum value of the minimum principal stress occurs on the 8 m protective coal pillar; The values of the principal stress ratio and the principal stress deflection angle do not differ greatly in the protection of the coal pillar, and the fluctuation of the values is mainly concentrated in the vicinity of the back‐mining roadway; The second invariant of bias stress (J2) is mainly concentrated in the protective coal pillar near the side of the extraction zone, when the size of the protective coal pillar is reduced to 10 m, the J2 on the side of the extraction zone and the J2 on the side of the roadway are connected, and the whole protective coal pillar is under the influence of J2, which is basically the same as the damage pattern of the plastic zone; Based on the formula of limit balance theory to calculate the elastic core width of different sizes of protective coal pillars, and combined with the results of numerical simulation analysis, it finally concluded that the reasonable size of the protective coal pillar of this isolated island working face is 15 m.

Engineer CEOs and corporate investment efficiency

Purpose This paper aims to examine whether CEOs with an engineering background increase corporate investment efficiency (CIE). The authors further investigate the role of engineering directors on boards of the above association. Design/methodology/approach Drawing from upper-echelon theory, which suggests that corporate outcomes are a reflection of its top management characteristics, the authors hypothesise a positive association between engineer CEOs and CIE and a positive moderation role of the proportion of engineer directors on boards in the above association. The authors examine this link using a sample of Australian Securities Exchange 200 firms from 2015 to 2022. Engineer CEO data is hand-collected from corporate annual report biographies and investment efficiency is a measure that captures whether the investments are maintained at optimal levels relative to industry-year benchmarks, following the approaches of Biddle et al. (2009), Chen et al. (2011) and the average values of both models. Findings The results indicate support for the hypotheses, revealing that firms managed by engineer CEOs have higher investment efficiency than their counterpart firms. This association is exacerbated in the presence of a higher proportion of engineer directors on boards. The results are robust to year and industry-fixed effects, propensity score matching, alternative measures of investment efficiency and robust standard errors. Our results also remain valid for an industry sub-sample using certain industries in which engineering expertise maybe more desirable (e.g. metals and mining). Research limitations/implications By showing that engineer CEOs are significantly associated with CIE, the authors contribute to upper-echelon literature examining the link between CEO characteristics and corporate outcomes, particularly, investment decision efficiency. The influence of engineering background on corporate outcomes is less examined in the literature; thus, the authors contribute to this thin literature. Originality/value The findings are informative to potential investors in evaluating firms’ investment efficiency before investing in firms. For example, firms with engineer CEOs are likely to maintain efficient investment levels in future years.

Anti-Seismic Performance Research of Complicated Nodes Involved in Ultra-Limited Steel Structures Subjected to Rare Occurrence Earthquakes

This study focuses on the seismic performance of complicated nodes in the ultra-limited steel structure under rare occurrence earthquakes. The Xi’an Urban Exhibition Center (Chang’an Cloud) is chosen as the engineering background, and the ANSYS (18.0) analysis software is employed. Based on the overall importance and the extent of post-damage impacts, the critical nodes are selected for structural design. The research aims to develop simplified and reliable structural forms that can withstand the most adverse conditions at both the overall nodes and local component levels. Stress distribution under the most unfavorable scenarios is calculated to achieve the seismic design objectives of the overall structure. The research results indicate that localized stress concentration areas can reach or exceed the yield strength of the steel, which enters the plastic phase. The Von Mises stresses in the remaining nodes are lower than the yield strength of the steel. The overall performance is excellent without significant plastic deformation. Thus, the design requirements for non-yielding performance under rare seismic events are met. The conclusions can provide reliable references for the critical structural techniques and seismic design of complicated nodes.

Prevention and Control of Spontaneous Combustion of Coal in the Goaf Under Z+I Ventilation Based on 2GN00 mining Process

ABSTRACT Traditional coal pillar mining technology will cause the waste of resources, and the roadway excavation. The N00 process eliminates the need for roadway excavation and coal pillar storage. The ventilation mode under the N00 construction method differs from conventional U-shaped ventilation. It is difficult to determine the danger area of spontaneous combustion. Therefore, this paper takes 21607 goaf with Z+I ventilation under the 2GN00 construction method in a mine in Guizhou province as the engineering background and adopts experimental research and numerical simulation methods to prevent and control coal spontaneous combustion hazards. Firstly, the spontaneous combustion tendency experiment determines the grade of spontaneous combustion tendency of coal samples. Secondly, the Fluent numerical simulation method is used to screen the optimal wind speed ratio of the two air inlets. Finally, numerical simulation is used to select the optimal spraying distance. The results show that the spontaneous combustion grade of coal samples makes it easy to produce spontaneous combustion. By analyzing the numerical simulation results of 6 groups of wind speed ratios, the best wind speed ratio of the two inlets is 1:1. Currently, the risk area of spontaneous combustion in the goaf is 5440.8 m2. Then the numerical simulation of the best slurry spraying distance is carried out with the wind speed ratio 1:1. The optimum distance of 90 m was finally determined. The area of the spontaneous combustion hazards area was reduced to 2223.8 m2. The results provide theoretical guidance and technical support for engineering applications.

Research on the Simplified Calculation Model and Parameter Analysis of Large-Size PBL-Stiffened Steel–Concrete Joints

To investigate the design principles and simplified calculation model of large-size PBL-stiffened steel–concrete joints, this study uses a Y-shaped rigid frame-tied arch composite bridge as an engineering background. Based on deformation coordination theory, a combination of theoretical analysis and numerical simulation was employed to derive a simplified calculation model that accounts for boundary conditions such as the stiffness of steel beam end restraints and the local bearing effect of the bearing plate. Parametric analysis of the steel–concrete joint was conducted. The results indicate that the derived simplified calculation model exhibits good accuracy and is suitable for calculating force transfer in various components of the steel–concrete joint under different boundary conditions. Using the simplified model, the effects of parameters such as steel–concrete joint length, connector stiffness, and structural axial stiffness on the axial force transfer in primary force-bearing components (connectors and bearing plates) were studied. The findings reveal that an excessively long steel–concrete joint does not effectively reduce maximum shear force; variations in connector stiffness primarily affect connectors farther from the bearing plate without changing the shear force distribution. Increasing the axial stiffness of the steel structure within a certain range can improve the maximum shear force in connectors, whereas increasing the axial stiffness of the concrete structure has the opposite effect.

Research on Roof Cutting and Pressure Relief Technology of Gob-side Entry Retaining with Hard Roof

Traditional coal pillar roadway protection is easy to cause roadway stress concentration, roadway deformation instability, and low recovery rate of coal resources. In order to solve the stability of roadway mining process and coal mine efficiency. Aiming at the problem of gob-side entry protection by deep hole pre-splitting blasting with hard roof, taking 1207 working face of Jiegou Coal Mine as the engineering background, through theoretical analysis, numerical simulation, field industrial test and other methods, the technology of roof cutting and pressure relief and constant resistance anchor cable reinforcement and roadway protection is put forward, and the key parameters such as appropriate roof cutting height and roof cutting angle are analyzed to achieve the effect of roof cutting and pressure relief, and the roadway reinforcement support scheme is designed. The field research shows that the roof cutting and roadway protection technology has a good control effect on 1207 working face roadway, realizes the safe production of working face, and provides certain reference value for this similar condition.

Research on Teaching Reform of Smoke Control and Exhaust Course under the Background of New Engineering

A large number of fire cases have proven that smoke is the main cause of casualties in fires, with over 80% of victims dying directly or indirectly due to smoke. Scientific and rational design of smoke control systems is crucial for slowing down the spread of fires and ensuring safe evacuation time. At present, the process of smoke exhaust in fire scenes is still the main way of fire rescue utilization, and industries related to smoke exhaust are also one of the main employment areas for undergraduate students majoring in fire engineering. However, traditional smoke exhaust engineering courses have outdated teaching content, teaching methods, and assessment methods, which cannot meet the demand for cultivating technical talents in energy engineering majors under the background of new engineering construction. This study first starts from the characteristics of smoke control engineering courses and the problems existing in teaching. Using advanced online teaching platforms, advanced teaching aids, mature commercial software, and computer programming language design environments, the teaching content of smoke control engineering courses is upgraded and transformed towards modular computing, intelligent design, and other directions. In the context of new engineering disciplines, students' learning interests are enhanced, and their practical, innovative, and comprehensive computing abilities are exercised.

A prestressed anchor-grouting reinforcement method based on the novel HFQSME grouting material for deep high-stress fractured rock mass

In order to control the surrounding rock of deep high-stress roadways, a new prestressed anchor-grouting reinforcement method was proposed with an engineering background of the 1780 ventilation roadway of Shiyakou Coal Mine. A high-fluidity quick-setting micro-expansion (HFQSME) grouting material had been developed through superplasticizer, accelerator, and expansion agent. The results showed that the optimal ratio of HFQSME grouting material was superfine Portland cement of 95%, superplasticizer of 0.5%, accelerator agent of 0.5%, expansion agent of 5.0%, and water-binder ratio of 0.4. The fluidity, initial setting time and expansion rate of the grouting material were 47cm, 41minutes and 0.12%, respectively. The grouting reinforcement effect of superfine slurry and HFQSME grouting material on rock mass with different degrees of fragmentation was investigated. The peak strength of rock mass with two degrees of fragmentation reinforced by HFQSME grouting material was 166% and 233% higher than that of superfine slurry. The macro reinforcement effect of HFQSME grouting material on the surrounding rock of deep high-stress roadway was evaluated through industrial testing. The prestressed anchor grouting method was used to improve the original support design scheme, and data monitoring and analysis were conducted on site. Compared with the original supporting scheme, the deformation of the 1780 ventilation was significantly reduced. Therefore, HFQSME grouting material had good adaptability for the surrounding rock of deep high-stress roadways.

Research on the Construction Path of New Engineering + Curriculum Ideology and Politics

With the rapid development of science and technology and the transformation and upgrading of industry, new engineering construction has become the important direction of higher engineering education reform in our country. This research focuses on the “new engineering + curriculum ideological and political new form course construction path,” in order to meet the new requirements of talent training put forward by the development of new engineering. This paper analyzes the educational value and current situation of curriculum ideology and politics under the background of new engineering, and improves the ability of curriculum ideology and politics from the perspective of strengthening the teacher training system; optimizing curriculum ideological and political design, skillfully integrating into the ideological and political elements; and strengthening the cooperation between schools, enterprises, and family associations to enrich curriculum ideological and political resources. To build a collaborative education mechanism and form an all-round education pattern, the four aspects of the new engineering + curriculum ideological and political of the new form course construction path have been preliminarily explored, hoping to provide some references and guidance.

Research on Key Parameters of Wellbore Stability for Horizontal Drilling in Offshore Hydrate Reservoirs

The South China Sea has abundant reserves of natural gas hydrates, and if developed effectively, it can greatly alleviate the pressure on the energy supply in China. But the hydrate reservoirs in the sea area are loose, shallow, porous, and have poor mechanical properties. During the drilling process, the invasion of drilling fluid into this kind of reservoir is likely to induce mass decomposition of gas hydrate and, in turn, a significant reduction in mechanical strength around the wellbore as well as instability of the wellbore. In this study, in light of the engineering background of exploratory wells at the South China Sea, a temperature and pressure field model in a gas hydrate reservoir at sea during open circuit drilling was established, and then, based on this model, a comprehensive model for the stability analysis of the well drilled in the hydrate reservoir at sea was constructed, both of them with errors of less than 10%. With these two models, the effects of different drilling parameters on wellbore stability were investigated. The gas and liquid produced by the decomposition of hydrates in the formation will increase the pore pressure in the formation, thereby reducing the effective stress in the formation. The closer the formation is to the wellbore, the more thorough the decomposition of hydrates in the formation and the greater the effective plastic strain. Keeping all other conditions constant, the increase in drilling fluid invasion pressure and temperature, as well as reservoir permeability, will lead to a decrease in the mechanical strength of the formation around the wellbore and an expansion of the wellbore yield zone. The results can provide a theoretical reference for the stability analysis at sea.

Simulation study of pharmaceutical supply chains based on system dynamics

Focusing on the multi-stage complex logistics distribution process of distribution centers, this study proposes and establishes a characteristic state model, analysis, and control methods for logistics distribution centers. These are combined with system dynamics simulation methods for logistics systems to conduct an in-depth study on the optimization and control of distribution center operations. Based on actual distribution process data from a pharmaceutical logistics distribution center, the proposed theories and methods are validated against real-world engineering backgrounds.

Exploring the Teaching of Curriculum Politics in Biomass Conversion Principles and Technology Based on the New Engineering Background

Exploring the Teaching of Curriculum Politics in Biomass Conversion Principles and Technology Based on the New Engineering Background

Modal Frequency Shifts Measured on Xinjiang Bridge Excited by Traveling Vehicles

To excite sufficient vibrations of bridges for more effective modal experiments to take place, traveling vehicles were utilized in many bridge field inspection campaigns in history. However, the dynamics of a bridge subjected to the traveling vehicles are of changed resonant properties compared with those of the same structure with the ambient excitation in nature. Therefore, the field modal experiments employing vehicle excitations might unfavorably lead to shifted measurement results of low-order natural frequencies for long-span bridges of large mass. Using Xinjiang Bridge (a single-tower pre-stressed concrete cable-stayed bridge with spans [Formula: see text]) as the engineering background, this paper validates this technical notion based on reliable physical experiments and numerical simulations and seeks a practical approach to deal with the issue. It is found that the maximum deviation between the low-order modal frequencies measured on Xinjiang Bridge for the vehicle excitation case and those measured for the ambient excitation case (the accurate values) reaches 0.65[Formula: see text]Hz, and the deviation between the lower limit of the usual vehicle excitation’s energy band and the modal frequency measured (factor 1) and the traveling vehicles’ speed (factor 2) are the two key factors influencing the modal frequency shifts. An empirical model to compensate for modal frequencies’ deviations is formulated considering the two key factors accordingly, which is of high-practical significance in future applications of the modal experiments using vehicle excitations to other long-span bridges.