Large-scale Engineering Research Articles

Integrated alliance system architecture for lifecycle risk management in large-scale complex engineering projects

Integrated alliance system architecture for lifecycle risk management in large-scale complex engineering projects

Fixing the Huai River: Technology of Labor Formation in Maoist China, 1950-53.

This article contributes to the large-scale engineering scholarship by revealing the labor practices involved and the state's role in shaping them. It provides a history of labor formation through earthwork technology in China's 1950s Huai River Control Project. The Communist Party's approach to engineering and labor differed from its Nationalist predecessor's. The party mobilized millions of peasants to dig and move an astronomical amount of soil in a few years. This herculean feat was made possible by promoting "work methods" to encourage peasants' self-Taylorization. The campaign aimed to cultivate a habit to work efficiently in mass-scale collaboration under external instructions. Through promoting work methods, state-appointed cadres assumed a tutelage role that allowed them to replace labor foremen. A hierarchical cadre-laborer relationship emerged from the same labor process that changed the nation's landscape.

Late Holocene Climate Warming Events and Their Linkage to Hydraulic Engineering on the Coast of Hangzhou Bay, East China

The coastal lowlands in East China are very sensitive to climate change and marine disasters, and much large-scale hydraulic engineering was recorded in the historical documents of the Late Holocene. In this study, AMS 14C and OSL were used to date three sedimentary profiles from the north and south coasts of inner Hangzhou Bay, and grain size and geochemical analyses including organic carbon, macro-elements, and alkaline earth metals were performed, while hydraulic engineering records in historical documents were compiled, in an attempt to reveal the sedimentary records of extreme climatic and hydrological events over the past 3000 years and to probe into the correlation between them and hydraulic engineering. The results show that the intensified chemical weathering during ca. 200 BCE to 900 CE in East China corresponded to the warm and humid climate during the Qin-Han and Sui-Tang dynasties. Salinity intrusion with rising local water levels occurred in the lowland plains along the south coast of Hangzhou Bay from 120 to 895 CE. Low-salinity water intrusion from 32 to 488 CE was also recorded in the stratigraphy of lowland plains along the north coast of Hangzhou Bay. The sedimentary records of the East Tiaoxi River basin show river floods about 2000 years ago. The above sedimentary records indicate that the relative sea level rose in the Hangzhou Bay area during the Qin-Han and Sui-Tang Warm Periods, resulting in frequent salinity intrusion and river floods, which coincided with the historical records of hydraulic engineering such as the construction of seawalls, river levees, and the enclosure of lakes for restoration of river floods during the Han and Tang dynasties. Such coincidence reflects that climate change profoundly affected the hydrological environment of the coastal areas in East China as well as the response of the human societies.

Review of research progress and development trend of digital image correlation

PurposeThe purpose of this paper is to provide a comprehensive review of a non-contact full-field optical measurement technique known as digital image correlation (DIC).Design/methodology/approachThe approach of this review paper is to introduce the research pertaining to DIC. It comprehensively covers crucial facets including its principles, historical development, core challenges, current research status and practical applications. Additionally, it delves into unresolved issues and outlines future research objectives.FindingsThe findings of this review encompass essential aspects of DIC, including core issues like the subpixel registration algorithm, camera calibration, measurement of surface deformation in 3D complex structures and applications in ultra-high-temperature settings. Additionally, the review presents the prevailing strategies for addressing these challenges, the most recent advancements in DIC applications across quasi-static, dynamic, ultra-high-temperature, large-scale and micro-scale engineering domains, along with key directions for future research endeavors.Originality/valueThis review holds a substantial value as it furnishes a comprehensive and in-depth introduction to DIC, while also spotlighting its prospective applications.

An energy-based chemo-thermo-mechanical damage model for early-age concrete

Cracking prediction and control in hydration process of mass concrete and structures has always been a challenging task. In this work, an energy-based chemo-thermo-mechanical damage model for early-age concrete is well established within the framework of thermodynamics and continuum damage mechanics. The evolution laws for the mechanical damage are driven by the work conjugate elastoplastic damage energy release rates to fully represent the microcracks closure-reopening effect, the anisotropy, and the aging effect of concrete relating to the degree of hydration. A formulation fitted from a large number of test data is introduced to simulate the thermal evolution during hydration process, resulting in an excellent approximation of the degree of hydration. When the degree of hydration is 1, the model is degenerated into the classical plastic damage model. The presented model is thus able to simulate the hydration process of early-age concrete and mechanical responses of concrete as well as reinforced concrete structures at any age. The model is implemented by user defined subroutine in Abaqus, in which a sequential coupling method is established. Several benchmark tests are successfully reproduced, indicating that the proposed model is capable of predicting the damage evolution and typical nonlinear behavior of early-age concrete and hardened concrete. The computational efficiency of the model is significantly improved compared to the classical ones due to the introduction of the fitting formulation of the thermal evolution and the sequential coupling method to reduce the nonlinearity of the system. The strategy allows the model to be applied in massive concrete structures during construction and provide valuable prediction as well as guidance for large scale engineering structures.

Feasibility and challenges of multi-source coal-based solid waste (CSW) for underground backfilling − A case study

The multi-source CSW produced in coal mining, power generation and coal chemical industry has become a bottleneck that restricts the green, low-carbon and high-quality development of coal power and coal chemical bases (CPCCBs) in China due to its large stock, many increments and low utilization rate. Underground backfilling has opened up a new way for CPCCBs to dispose of multi-source CSW, and it is also the most practical way, which is conducive to solve the surface accumulation of CSW and reducing the environmental pollution risk. Based on the physicochemical properties and pollution, the feasibility of underground backfilling with multi-source CSW was systematically analyzed from four aspects: environment, technology, economy and policy. Most CSWs can be directly for underground backfilling; the high potential pollution risks of individual CSWs can reduce through technical measures such as heavy metal adsorption and complex passivation, then safely for underground backfilling. Although underground backfilling with multi-source CSWs is feasible, there are still some challenges before achieving large-scale engineering applications, such as potential risks of CGS, technical maturity, economic investment and administration. It requires the joint efforts and cooperation of research institutions, enterprises and governments to realize the harmless and large-scale underground backfilling with multi-source CSW.

Prediction Model of Residual Soil Shear Strength under Dry–Wet Cycles and Its Uncertainty

Granite residual soil is widely distributed in Southeast Fujian. Large-scale engineering construction leads to the exposure of residual soil slopes to the natural environment. Affected by seasonal climate factors, the soil of slopes experiences a dry–wet cycle for a long time. The repeated changes in water content seriously affect the shear strength of soil, and then affect the stability of the slope. In order to explore the influence of the dry–wet cycle on the shear strength of granite residual soil in Fujian, an indoor dry–wet cycle simulation test was carried out for shallow granite residual soil on a slope in Fuzhou, and the relationship between water content, dry–wet cycle times, and the shear strength index, including the cohesion and internal friction angle of the granite residual soil, was discussed. The results show that when the number of dry–wet cycles is constant, the cohesion and internal friction angle of the granite residual soil decrease with an increase in water content. The relationship between the cohesion, internal friction angle, and water content can be described using a power function. Meanwhile, the fitting parameters of the power function are also a function of the number of wet and dry cycles. The prediction formulas of the cohesion and internal friction angle considering the number of dry–wet cycles and water content are established, and then the prediction formula of shear strength is obtained. The ratio of the predicted value of shear strength to the test value shall be within ±15%. An error transfer analysis based on the point estimation method shows that the overall uncertainty of the predicted value of shear strength caused by the combined uncertainty of the predicted value of cohesion and the internal friction angle and the single-variable uncertainty of the predicted value of shear strength caused only by the uncertainty of the predicted value of either the cohesion or internal friction angle increases first and then decreases with an increase in the number of dry–wet cycles. All increase with an increasing water content. The maximum standard deviation of the proposed shear strength prediction model of granite residual soil is less than 9%.

Mouse genome rewriting and tailoring of three important disease loci

Genetically engineered mouse models (GEMMs) help us to understand human pathologies and develop new therapies, yet faithfully recapitulating human diseases in mice is challenging. Advances in genomics have highlighted the importance of non-coding regulatory genome sequences, which control spatiotemporal gene expression patterns and splicing in many human diseases1,2. Including regulatory extensive genomic regions, which requires large-scale genome engineering, should enhance the quality of disease modelling. Existing methods set limits on the size and efficiency of DNA delivery, hampering the routine creation of highly informative models that we call genomically rewritten and tailored GEMMs (GREAT-GEMMs). Here we describe ‘mammalian switching antibiotic resistance markers progressively for integration’ (mSwAP-In), a method for efficient genome rewriting in mouse embryonic stem cells. We demonstrate the use of mSwAP-In for iterative genome rewriting of up to 115 kb of a tailored Trp53 locus, as well as for humanization of mice using 116 kb and 180 kb human ACE2 loci. The ACE2 model recapitulated human ACE2 expression patterns and splicing, and notably, presented milder symptoms when challenged with SARS-CoV-2 compared with the existing K18-hACE2 model, thus representing a more human-like model of infection. Finally, we demonstrated serial genome writing by humanizing mouse Tmprss2 biallelically in the ACE2 GREAT-GEMM, highlighting the versatility of mSwAP-In in genome writing.

Damage identification and failure morphological reconstruction for engineering rock mass

By and large, the traditional CT technology cannot involve the important problems of intrinsic damage identification and reconstruction of large-scale engineering rock mass. In the light of the numerical simulation technology, the digital image processing technology and the three-dimensional reconstruction technology, a kind of numerical computed tomography method is proposed. On the basis of numerical simulation, the external program of the characteristic variable of rock mass damage and failure is called to generate the cloud map model of rock mass damage and failure. In addition, the sequence layered profile images are created by automatically cutting the cloud map model via the self-complied program, as well as adopting the digital image processing technology for batch cropping, batch gray-scale and binarization processing. Eventually, the three-dimensional reconstruction technology is employed to reconstruct the spatial distribution morphology of the internal damage and failure of rock mass. At that point, the proposed method is applied to apparently exhibit the evolution morphology of spatial distribution of the Rm 417 tunnel failure area, and effectively reveal the intrinsic connection of the Rm 417 tunnel failure, such as the location, evolution path and morphology. Consequently, the validity and reliability of the numerical computed tomography method are verified, which has satisfactory applicability and applied values.

Ultrahigh intermediate-temperature strength and good tensile plasticity in chemically complex intermetallic alloys via lamellar architectures

As a newly emerged class of materials, chemically complex intermetallic alloys (CCIMAs) with exceptional thermal and mechanical properties are a promising candidate for high-temperature structural use. However, serious intergranular embrittlement at intermediate temperatures (600∼800 °C) is frequently found in those CCIMAs, obstructing their large-scale engineering applications. In this study, through deliberately tailoring thermomechanical processing, we designed a lamellar-structured (LS) L12-type Co-Ni-Al-Ti-Ta-Nb-B-based CCIMA that effectively overcomes this critical issue. The LS-CCIMA exhibits an excellent yield strength (YS) of ∼1.0 GPa with a large tensile elongation of ∼17% at room temperature. More prominently, it also presents an anomalous YS of ∼1.2 GPa combined with an acceptable tensile elongation of ∼10% at intermediate temperatures ranging from 600 to 800 °C, outperforming those of many other simple ordered intermetallics and conventional superalloys. Such superb immediate-temperature strengths primarily originate from the high anti-phase boundary energy caused by the addition of multiple alloying elements (Ti, Ta, and Nb) and the pile-ups of geometrically necessary dislocations. Moreover, we attribute the acceptable tensile plasticity to the increased plastic deformation capacities from the activation of various deformation-induced substructures (e.g., dislocation pairs at 600 °C and superlattice intrinsic stacking faults at 800 °C) and the inhibiting mechanisms of the lamellar structures on oxygen-induced grain boundary damage and microcrack's propagation. This work provides a new pathway for the innovative design of strong-yet-ductile heat-resistant CCIMAs.

A localized Fourier collocation method for 2D and 3D elastic mechanics analysis: Theory and MATLAB code

This paper documents the first attempt to apply the localized Fourier collocation method (LFCM), a recently published meshless collocation method, for solving 2D and 3D elastostatic problems. The approach first divides the entire domain into a series of intersecting sub-domains. Within each sub-domain, the unknown functions are approximated by utilizing the pseudo-spectral Fourier collocation technique. The method integrates the merits of the rapid convergence of the pseudo-spectral method and the high sparsity of the localized discretization technique. This combination results in a novel framework that is highly suitable for large-scale and high-precision engineering simulations. Extensive numerical experiments, involving both 2D and 3D elastostatic problems, are presented to showcase the precision and efficiency of the current method. The source codes for numerical examples studied in this work are also provided.

Improved Dual-Population Genetic Algorithm: A Straightforward Optimizer Applied to Engineering Optimization

Aiming at the current limitations of the dual-population genetic algorithm, an improved dual-population genetic algorithm (IDPGA) for solving multi-constrained optimization problems is proposed by introducing a series of strategies, such as remaining elite individuals, a dynamic immigration operator, separating the objective and constraints, normalized constraints, etc. We selected 14 standard mathematical benchmarks to check the performance of IDPGA, and the results were compared with the theoretical value of CEC 2006. The results show that IDPGA with the current parameters obtains good solutions for most problems. Then 6 well-known engineering optimization problems were solved and compared with other algorithms. The results show that all of the solutions are feasible, the solution precision of IDPGA is better than other algorithms, and IDPGA performs with good efficiency and robustness. Meanwhile, no parameters need to be ignored when IDPGA is applied to solving engineering problems, which is enough to prove that IDPGA is suitable for solving engineering optimization. A Friedman test showed no significant difference between IDPGA and six algorithms, but significant differences between IDPGA and seven other algorithms; thus, a larger number of evaluators will be needed in the future. In addition, further research is still needed about the performance of IDPGA for solving practical large-scale engineering problems.

Advances in Technologies in Crime Scene Investigation.

Crime scene investigation (CSI) is the complex act of reconstructing the dynamics that led to a crime and the circumstances of its perpetration. Crystallizing the CSI is a difficult task for the forensic pathologist; however, it is often requested by the public prosecutor and many judicial cases remain unsolved precisely for this reason. Recent years have seen an improvement in the ability of 3D scanning technology to obtain dense surface scans of large-scale spaces, for surveying, engineering, archaeology, and medical purposes such as forensics. The applications of this new technology are growing every day: forensic measurement of wounds in clinical reports, for example, reconstruction of traffic accidents, bullet trajectory studies in gunshot wounds, and 3D bloodstain pattern analysis. A retrospective analysis was conducted across all crime scene investigations performed by the forensic staff of the Department of Forensic Pathology of the University of Catania from January 2019 to June 2022. Inclusion criteria were the use of a laser scanner (LS), the use of a camera, a full investigative scene, and collection of circumstantial data thanks to the help of the judicial police. Cases in which the LS was not used were excluded. Out of 200 CSIs, 5 were included in the present study. In case number 1, the use of the LS made it possible to create a complete scale plan of the crime scene in a few hours, allowing a ship to be quickly returned to the judicial police officer. In case 2 (fall from a height), the LS clarified the suicidal intent of the deceased. In case number 3 it was possible to reconstruct a crime scene after many years. In case 4, the LS provided a great contribution in making a differential diagnosis between suicide and homicide. In case 5, the LS was fundamental for the COVID team in planning the study of COVID-19 pathways and areas within a hospital with the aim of reduction of nosocomial transmission. In conclusion, the use of the LS allowed the forensic staff to crystallize the investigative scene, making it a useful tool.

Design of Aquaponics System Based on Offshore Equipment

Offshore equipment is a large-scale engineering device set up in the open sea area of the deep and distant sea, which is an important way to expand the new area of aquaculture, oil and gas development and so on. In order to solve the problem of replenishment difficulty and wastewater discharge pollution existing in offshore equipment, this paper is based on the current situation of practical research and application of offshore equipment, through the literature and data calculation, systematic design of an aquaponics system based on offshore equipment, through the aquaponics system, through the automation of the data processing system, intelligent control, in the offshore equipment platform to achieve the soilless cultivation of vegetables, cultivation of fish fry in the tail water nitrification tank processing Recycling. The aquaponics system designed in this paper, in ecological, economic and social aspects, there is a positive role in promoting, especially for the future of offshore equipment independent operation to do the corresponding possibility of exploration, for the design and construction of supporting facilities for offshore equipment to provide advice and thinking.

RISK ASSESSMENT OF COMPLEX ENGINEERING PROJECT BASED ON FUZZY PETRI NET UNDER THE PERSPECTIVE OF VULNERABILITY

Traditional engineering risk management has been unable to adapt to the complexity and variability due to its constituent elements and dynamic nature of internal and external environments. Vulnerability, as a concept closely related to risk, has been neglected in the traditional risk management due to its hidden characteristics. This study attempts to quantify and evaluate vulnerabilities of complex engineering projects independently and explore the transmission mechanism between risk and vulnerability factors. Twenty different types of large-scale engineering projects in China were selected as case studies from the Mega Project Case Study Center (MPCSC) of Tongji University. Vulnerability and risk factors of each project were identified and analysed. A mechanism model was developed to explore the impacts of vulnerabilities and risks through ta Fuzzy Petri Net. Four main vulnerability-risk critical paths were identified through the reverse labelling method. The overall evaluation of engineering project risks considering the impacts of vulnerabilities is the highlight of this paper. This study interprets the cognition and evaluation of complex engineering risks from a new perspective, enriches the connotation of engineering risk management, and provides a reference for risk management and decisionmaking of complex engineering projects.

A Review of Effect of Mineral Admixtures on Appearance Quality of Fair-Faced Concrete and Techniques for Their Measurement

The appearance of fair-faced concrete is crucial, and it can be enhanced by incorporating an appropriate amount of mineral admixture. Different mineral admixtures have varying effects on the appearance quality of fair-faced concrete. For instance, the addition of fly ash helps control color differences and bubble formation on the concrete surface, while slag powder effectively controls its color and finish. In this review, the impact of using various mineral admixtures, such as silica fume, rice husk ash, limestone powder, and seashell powder, in fair-faced concrete on its appearance quality is examined. The effective combination of mineral admixtures made from industrial by-products or solid waste with fair-faced concrete can pave the way for new directions in the green and sustainable development of construction materials. This review also discusses the difficulties in objectively measuring the appearance quality of concrete and the various methods for the acquisition and evaluation of appearance images. New techniques for acquiring and evaluating information about concrete surfaces have been developed with advancements in image acquisition and processing technology. These techniques complement traditional manual inspection methods. The 3D Alicona system is advantageous for identifying air bubbles on concrete surfaces, the atomic-force microscope detects surface roughness, and the Orbital large-format scanner is ideal for use in large-scale engineering applications. Also, evaluation methods for different image processing software are presented in this article. This information offers a useful reference for future research and practical application.

Analysis of air quality issues and air quality management status in five major African cities

Poor air quality is one of the main dysfunctions of the rapid urbanisation process in Africa. Although the information is fragmented, the limited evidence available points out that air quality is a leading health risk in Africa, especially affecting the poorest, most vulnerable communities. In this study, we look into five cities in Africa to understand the nature of urban air quality issues and to delve into the initial responses. We report on the status of the main air quality management dimensions, including air quality standards and monitoring strategy/capabilities, emission inventories and air quality modelling, health impact assessment studies, communication practices, development and implementation of clean air action plans (in connection with other relevant strategies, i.e. climate change policies) and governance issues. We find that all cities have limited monitoring capabilities although communication strategies may differ substantially. While indoor pollution sources are declining in more developed economies, traffic is a growing concern in all five cities. In most cases, air quality issues are mostly related to PM2.5 and natural contributions worsen air pollution from road transport, biomass and open waste burning. While nationally-driven strategies, often based on large-scale engineering projects and financial schemes, may report substantial gains in early stages, multi-level governance and planning is likely to maximize benefits and provide a useful framework for the complex problem of air quality management in the long run. The integration of air quality plans in overarching strategies to tackle persistent poverty and social inequity is urgently needed.

Mathematical Model of Three-Component Suspension Transport

Introduction. Prediction of suspension deposition zones is required to assess and minimize the negative impact on the ecosystem of the reservoir during dredging within the framework of large-scale engineering projects, prediction of suspension deposition zones is required to assess and minimize the negative impact on the ecosystem of the reservoir. It is necessary to build a mathematical model that takes into account many factors that have a significant impact on the accuracy of forecasts. The aim of the work is to construct a mathematical model of transport of multicomponent suspension, taking into account the composition of the soil (different diameter of the suspension particles), the flow velocity of the water flow, the complex geometry of the coastline and bottom, wind stresses and friction on the bottom, turbulent exchange, etc.Materials and Methods. A mathematical model for the transport of a multicomponent suspension and an approximation of the proposed continuous model with the second order of accuracy with respect to the steps of the spatial grid are described, considering the boundary conditions of the Neumann and Robin type. The approximation of the hydrodynamics model is obtained based on splitting schemes by physical processes, which guarantee fulfillment mass conservation for discrete model.Results. The proposed mathematical model formed the basis of the developed software package that allows to simulate the process of sedimentation of a multicomponent suspension. The results of the work of the software package on the model problem of sedimentation of a three-component suspension in the process of soil dumping during dredging are presented.Discussions and Conclusions. The mathematical model of transport of three-component suspension is described and software implemented. The developed software allows to simulate the process of deposition of suspended particles of various diameters on the bottom, and to evaluate its effect on the bottom topography and changes in the bottom composition. The developed software package also allows to analyze the process of sediment movement in the case of resuspension of multicomponent bottom sediments of the reservoir, which causes secondary pollution of the reservoi

Pore scale analysis for flow and thermal characteristics in metallic woven mesh

Metallic woven mesh screens are representative porous media with periodic structures, which have great application prospects in emerging technology and industrial equipment. However, the effect of their pore structure on macroscopic properties is not clear, which limits their large-scale engineering application. In this paper, to investigate the influence mechanism of stacking patterns and wire contact conditions on flow and heat conduction from the pore scale, a representative elementary volume model of the square-shaped plain copper micromesh was reconstructed according to the geometric parameters obtained by the optical microscope and porosity test experiment. Furthermore, based on the understanding of microscopic mechanism, the theoretical calculation model for macroscopic characteristics was proposed. The results show that the flow characteristics in meshes are mainly affected by stacked patterns. When ReK is 0.08 and 0.28, the flow in single layer and staggered stacked woven meshes transitions from Darcy flow to Forchheimer flow. In Forchheimer flow regime, neglecting the inertia force causes a maximum 50 % error for permeability calculation. The permeability empirical correlations for Darcy and Forchheimer flow are proposed according to Kozeny-Carman and Kozeny-like model. The z-direction effective thermal conductivity of copper woven meshes is significantly affected by wire contact conditions, the maximum value is from 2.5 to 13.5 W/(m·K). The z-direction effective thermal conductivity of tangent and gap contact conditions can be described by the ZBS model, while the random model is suitable for that of overlapped contact conditions. The x-direction thermal conductivity is little affected by contact conditions, the maximum value is 50.3 W/(m·K), but the tortuosity effect of copper wires should be considered for calculation. The calculation model of anisotropic thermal conductivity for single-layer woven meshes is established according to Kirchhoff's law, which is also extended to the staggered stacked woven meshes by introducing a compactness factor.

Impact of mini-hydropower on the chemical composition of water and phytoplankton of the reservoirs of the Forest-Steppe of Ukraine

The peculiarities of the transformation of river ecosystems in the reservoir at the construction of mini-hydropower plants have been found out. It was also found that the large-scale hydraulic engineering in the second half of the XX century caused significant changes in environmental conditions in the waterbodies, which has led to negative dynamics of species richness of aquatic organisms in general and phytoplankton in particular. Reservoir building has a significant negative impact on river ecosystems: currents slow down and disappear, canals become silted up, harmful substances of household and industrial waste gradually accumulate. The transformation of rivers into lake-type reservoirs is also accompanied by changes in the species composition and structure of phytoplankton. Eutrophication of reservoirs becomes typical. All this leads to significant degradation in aquatic ecosystems.