ADVANCED NICKEL-BASED AND NICKEL-IRON-BASED SUPERALLOYS FOR CIVIL ENGINEERING APPLICATIONS

The use of high-temperature materials is especially important in power station construction, heating systems engineering, furnace industry, chemical and petrochemical industry, waste incineration plants, coal gasification plants and for flying gas turbines in civil and military aircrafts and helicopters. Particularly in recent years, the development of new processes and the drive to improve the economics of existing processes have increased the requirements significantly so that it is necessary to change from well-proven materials to new alloys. Hitherto, heat resistant ferritic steels sufficed in conventional power station constructions for temperatures up to 550℃ newly developed ferritic/martensitic steels provide sufficient strength up to about 600 - 620℃. In new processes, e.g. fluidized-bed combustion of coal, process temperatures up to 900℃ occur. However, this is not the upper limit, since in combustion engines, e.g. gas turbines. Material temperatures up to 1100℃ are reached locally. Similar development trends can also be identified in the petrochemical industry and in the heat treatment and furnace engineering. The advance to ever higher material temperatures now not only has the consequence of having to use materials with enhanced high-strength properties, considerable attention now also has to be given to their chemical stability in corrosive media. Therefore not only examples of the use of high-temperature alloys for practical applications will be given but also be contributed to some general rules for material selection with regard to their high-temperature strength and corrosion resistance.

Paving Materials and Engineering Applications of Permeable Pavement

The stability of roads in cities directly affects the safety of traffic and transportation.In the process of pavement laying,relevant personnel should use permeable paving materials in the process of construction.Based on the analysis of road drainage requirements,traditional paving materials have relatively poor water permeability,which leads to ponding problems during road use[1].Within this frame of reference,beginning with the characteristics of permeable paving materials,this paper makes an in-depth exploration on practical application measures.

Evaluations of Chris-Jerry Data Using Generalized Progressive Hybrid Strategy and Its Engineering Applications

A new one-parameter Chris-Jerry distribution,created by mixing exponential and gamma distributions,is discussed in this article in the presence of incomplete lifetime data.We examine a novel generalized progressively hybrid censoring technique that ensures the experiment ends at a predefined period when the model of the test participants has a Chris-Jerry(CJ)distribution.When the indicated censored data is present,Bayes and likelihood estimations are used to explore the CJ parameter and reliability indices,including the hazard rate and reliability functions.We acquire the estimated asymptotic and credible confidence intervals of each unknown quantity.Additionally,via the squared-error loss,the Bayes’estimators are obtained using gamma prior.The Bayes estimators cannot be expressed theoretically since the likelihood density is created in a complex manner;nonetheless,Markov-chain Monte Carlo techniques can be used to evaluate them.The effectiveness of the investigated estimations is assessed,and some recommendations are given using Monte Carlo results.Ultimately,an analysis of two engineering applications,such as mechanical equipment and ball bearing data sets,shows the applicability of the proposed approaches that may be used in real-world settings.

Environmental standards and beneficial uses of waste-to-energy(WTE)residues in civil engineering applications

The waste-to-energy(WTE)technologies are now recovering energy and materials from over 300 million tonnes of municipal solid wastes worldwide.Extensive studies have investigated substituting natural construction materials with WTE residues to relieve the environmental cost of natural resource depletion.This study examined the beneficial uses of WTE residues in civil engineering applications and the corresponding environmental standards in Europe,the U.S.,and China.This review presents the opportunities and challenges for current technical approaches and the environmental standards to be met to stabilize WTE residues.The principal characteristics of WTE residues(bottom ash and fly ash)and the possible solutions for their beneficial use in developed and developing countries are summarized.The leaching procedures and environmental standards for pH,heavy metals,and polychlorinated dibenzo-p-dioxins/furans(PCDD/Fs)are compared.The current practice and engineering properties of materials using WTE residues,including mixtures with stone aggregate or sand,cement-based or hot-mix asphalt concrete(pavement),fill material in the embankments,substitute of Portland cement or clinker production,and ceramic-based materials(bricks and lightweight aggregate)are comprehensively reviewed.

Living concrete with self-healing function on cracks attributed to inclusion of microorganisms: Theory, technology and engineering applications——A review

Concrete is the most widely used composite material in civil engineering.Microbial induced calcium carbonate precipitation(MICP)is a green and environmental friendly technology,which has received extensive attention in repair of concrete cracks.This paper introduces the research progress in Southeast University research in past 16 years.In the early stage,MICP technology of urea hydrolyzed by Bacillus pasteurii was mainly investigated to repair the surface cracks and to fill large-size cracks with grouting.However,aiming at the hidden cracks that were difficult for human intervention,a new mineralization route of Bacillus mucilaginosus was proposed,which could repair faster than Bacillus alcalophilus,and the problem of ammonia emission in the repair process of Bacillus pasteurii was also solved.In addition,in order to improve the protection of bacteria and the self-healing efficiency of the later age cracks,the methods of fiber immobilization,carrier uniformly immobilization and core-shell structural immobilization had been compared and studied.The results showed that core-shell structural immobilization had good protection ability and strong designability.What’s more,the paper also summarized the characteristics of spore germination,cell activity,nucleation and biological calcium carbonate in crack zone,and introduced the application experience of microbial self-healing concrete in water conservancy projects and subway stations.

A survey of cloud resource management for complex engineering applications

Traditionally, complex engineering applications （CEAs）, which consist of numerous components （software） and require a large amount of computing resources, usu- ally run in dedicated clusters or high performance computing （HPC） centers. Nowadays, Cloud computing system with the ability of providing massive computing resources and cus- tomizable execution environment is becoming an attractive option for CEAs. As a new type on Cloud applications, CEA also brings the challenges of dealing with Cloud resources. In this paper, we provide a comprehensive survey of Cloud resource management research for CEAs. The survey puts forward two important questions： 1） what are the main chal- lenges for CEAs to run in Clouds？ and 2） what are the prior research topics addressing these challenges？ We summarize and highlight the main challenges and prior research topics. Our work can be probably helpful to those scientists and en- gineers who are interested in running CEAs in Cloud envi- ronment.

A New Two-Parameter Heteromorphic Elliptic Equation: Properties and Applications

The ellipse and the superellipse are both planar closed curves with a double axis of symmetry. Here we show the isoconcentration contour of the simplified two-dimensional advection-diffusion equation from a stable line source in the center of a wide river. A new two-parameter heteromorphic elliptic equation with a single axis of symmetry is defined. The values of heights, at the point of the maximum width and that of the centroid of the heteromorphic ellipse, are derived through mathematical analysis. Taking the compression coefficient θ = b/a = 1 as the criterion, the shape classification of H-type, Standard-type and W-type for heteromorphic ellipse have been given. The area formula, the perimeter theorem, and the radius of curvature of heteromorphic ellipses, and the geometric properties of the rotating body are subsequently proposed. An illustrative analysis shows that the inner contour curve of a heteromorphic elliptic tunnel has obvious advantages over the multiple- arc splicing cross section. This work demonstrates that the heteromorphic ellipses have extensive prospects of application in all categories of tunnels, liquid transport tanks, aircraft and submarines, bridges, buildings, furniture, and crafts.

A Fusion Localization Method Based on Target Measurement Error Feature Complementarity and Its Application

In the multi-radar networking system,aiming at the problem of locating long-distance targets synergistically with difficulty and low accuracy,a dual-station joint positioning method based on the target measurement error feature complementarity is proposed.For dual-station joint positioning,by constructing the target positioning error distribution model and using the complementarity of spatial measurement errors of the same long-distance target,the area with high probability of target existence can be obtained.Then,based on the target distance information,the midpoint of the intersection between the target positioning sphere and the positioning tangent plane can be solved to acquire the target's optimal positioning result.The simulation demonstrates that this method greatly improves the positioning accuracy of target in azimuth direction.Compared with the traditional the dynamic weighted fusion(DWF)algorithm and the filter-based dynamic weighted fusion(FBDWF)algorithm,it not only effectively eliminates the influence of systematic error in the azimuth direction,but also has low computational complexity.Furthermore,for the application scenarios of multi-radar collaborative positioning and multi-sensor data compression filtering in centralized information fusion,it is recommended that using radar with higher ranging accuracy and the lengths of baseline between radars are 20–100 km.

Perspective:Acoustic Metamaterials in Future Engineering

Acoustic metamaterials(AMMs)are a type of artificial materials that make use of appropriate structural designs and exhibit exotic properties not found in natural materials,such as negative effective material parameters(e.g.,bulk modulus,mass density,and refractive index).These interesting properties offer novel means for sound manipulation and thus have drawn a great deal of attention.Over the past two decades,tremendous progress has been made in the fundamental research of AMMs,which has not only promoted the development of modern acoustics but also shown the potential of AMMs for engineering applications.Here,we review recent developments in AMMs with a focus on their future engineering,especially in the most promising fields of sound absorption/isolation,acoustic imaging,cloaking,and so on,furthermore,we outline the opportunities and challenges they are encountering.

Application of iron oxide anoparticles in neuronal tissue engineering

Since the introduction of nanotechnology, nanoscale materials have developed rapidly and have been applied in various fields including in the pharmaceutical industry, medicine, and tissue engineering. Among a variety of nanomaterials, magnetic iron oxide nanoparticles （IONPs） have been intensively investigated for numerous in vivo applications such as gene and drug delivery, diagnostics, cell labeling and sorting. Compared to nanoparticles made from other materials, IONPs have several additional unique applications due to their magnetic properties, for example, magnetic cell separation,

Application of Monte-Carlo statistical experiments in design of ocean engineering - Estimating the parameters, models and probabilities

Recently, some results have been acquired with the Monte- Carlo statistical experiments in the design of ocean en gineering. The results show that Monte-Carlo statistical experiments can be widely used in estimating the parameters of wave statistical distributions, checking the probability model of the long- term wave extreme value distribution under a typhoon condition and calculating the failure probability of the ocean platforms.

Students’Feedback on Integrating Engineering Practice Cases into Lecture Task in Course of Built Environment

The improvement of students’abilities is of great significance to discover the relevant scientific problems in daily life,to analyze and solve practical problems,to trigger scientific inspiration,and to encourage innovation and entrepreneurship.Taken the course entitled Built Environment(BE)as an example,this study introduces five lecture cases combining with engineering practices,and examines the evaluation of teaching and learning effect on student outcomes.The cases consider various problems to be solved urgently in an actual project,and evaluate the student outcomes by statistically analyzing the questionnaires.Most of the students actively participate in five cases and cheerfully share their achievements.More than 85%of students are satisfied with the engineering practice and the learning proposal,and convey a little or even significantly change in their understanding of the employment prospects.

Editor's Choice——Application of genetic engineering for the treatment of neurodegenerative diseases

Gene therapy has been shown to be an effective method for protecting neural functions in the substantia nigra,

Attenuation of Chlorinated Contamination in Three Different Depths of Aquifers at Remediation Site

The cleanup of carbon tetrachloride(CCl4)in groundwater is challenging due to its high volatility and tendency to form a dense nonaqueous liquid phase.From the engineering applications perspective,the pump-and-treat(PAT)technology has substantial advantages owing to its large-scale implementation ability to solve groundwater contamination.However,few studies focused on the variation in chloride contaminants in remediation sites after the contaminated groundwater was pumped and treated.Herein,we monitored the changes in chlorinated contamination in groundwater from 12 aquifers at the field level for 6 months.Considering that the natural attenuation of chlorinated contamination is inseparable from the action of microorganisms,the major environmental factors influencing biodegradation were also evaluated.A redundancy analysis(RDA)showed that inorganic salts(DS,DN,and DF)were the most important factor(>60%)affecting the concentration of chloride contaminants,including the negative correlation between DN and the degradation of contaminants in shallow aquifers.In deep aquifers,DS,DF,and pH explained most of the degradation of chloride contaminants.For bedrock layers,DCl was positively relevant to the chloride contaminants in wells PTJ2 and PTJ10.In addition,EC and DS accounted for 73.2%and 92.4%of the contaminant’s variance in wells PTJ4 and PTJ8,respectively.Moreover,the concentrations of the corresponding contaminations and physicochemical variation in three different depths of aquifers were compared;the shallower aquifers showed a higher biodegradation.The in situ monitoring and analysis of contaminated groundwater in remediation sites under PAT will promote practical wastewater treatment technologies in engineering applications.

Research progresses of fibers in asphalt and cement materials:A review

Asphalt mixtures and cement concrete are an important material in the construction of roads,highways and buildings,and there has been a lot of research about the improvement of their performance.Among them,fibers are commonly used in the construction industry because of their superior properties as reinforcing materials that can provide a proper interfacial action between the fibers and the substrate.This review classifies fibers into natural fibers,inorganic fibers and polymer fibers according to their sources and properties.It summarizes and compares the characteristics,modification methods,usage requirements and research status of each type of fiber in asphalt and cement construction materials,and analyzes the problems and challenges faced by fibers in their applications.The evaluation results show that various types of fibers can enhance the fracture resistance,tensile strength and rutting resistance of asphalt to a certain extent,improve the high temperature performance and viscoelasticity of asphalt,and have a certain effect on the fatigue resistance and road water resistance of asphalt mixes.The fibers also provide better tensile,compressive and abrasion resistance to cement concrete and improve the brittleness and crack resistance of ordinary cement.Besides,for some defects of various types of fibers in construction materials,such as biodegradability,dispersibility and surface inertness of fibers,the targeted modification of fibers is introduced based on physical and chemical modification methods to improve the performance impact of modified fibers in various conditions of application.

FDSC-YOLOv8:Advancements in Automated Crack Identification for Enhanced Safety in Underground Engineering

In underground engineering,the detection of structural cracks on tunnel surfaces stands as a pivotal task in ensuring the health and reliability of tunnel structures.However,the dim and dusty environment inherent to under-ground engineering poses considerable challenges to crack segmentation.This paper proposes a crack segmentation algorithm termed as Focused Detection for Subsurface Cracks YOLOv8(FDSC-YOLOv8)specifically designed for underground engineering structural surfaces.Firstly,to improve the extraction of multi-layer convolutional features,the fixed convolutional module is replaced with a deformable convolutional module.Secondly,the model’s receptive field is enhanced by introducing a multi-branch convolutional module,improving the extraction of shallow features for small targets.Next,the Dynamic Snake Convolution module is incorporated to enhance the extraction capability for slender and weak cracks.Finally,the Convolutional Block Attention Module(CBAM)module is employed to achieve better target determination.The FDSC-YOLOv8s algorithm’s mAP50 and mAP50-95 reach 96.5%and 66.4%,according to the testing data.

Advance of in-situ stress measurement in China

In-situ stress is an essential parameter for design and construction of most engineering projects that involve excavation in rocks. Progress in in-situ stress measurement from the 1950s in China is briefly introduced. Stress relief by overcoring technique and hydraulic fracturing： technique are the two main techniques for in-situ stress measurement in China at present. To make them suitable for application at great depth and to increase their measuring reliability and accuracy, a series of techniques have been developed. Applications and achievements of in-situ stress measurement in Chinese rock engineering, including mining, geotechnical and hydropower engineering, and earthquake prediction, are introduced. Suggestions for further development of in-situ stress measurement are also proposed.