Construction Method Research Articles

Orientable sequences over non-binary alphabets

AbstractWe describe new, simple, recursive methods of construction for orientable sequences over an arbitrary finite alphabet, i.e. periodic sequences in which any sub-sequence of n consecutive elements occurs at most once in a period in either direction. In particular we establish how two variants of a generalised Lempel homomorphism can be used to recursively construct such sequences, generalising previous work on the binary case. We also derive an upper bound on the period of an orientable sequence.

Progress in the Development of Antifouling Electrochemical Biosensors

Electrochemical biosensors a subclass of biosensors, consisting of a biosensing element and an electrochemical transducer, have been widely used in various fields due to their excellent performance and portable device. However, in complex actual samples, non-specific adsorption of proteins and solid particles, and adhesion of cells and bacteria will lead to problems such as reduced sensor sensitivity, prolonged response time, and expanded detection errors. Therefore, constructing antifouling sensing platforms to effectively resist the bioadhesion of non-targets is crucial for the performance of biosensors. This study first introduces the commonly used classifications of electrochemical biosensors and their main contaminants. It also provides a comprehensive overview of the construction methods and application research of electrochemical antifouling sensors using different strategies, including the construction of physical, chemical and biological modification interfaces. In addition, the research progress on antifouling and antibacterial dual-action coatings for electrochemical detection is also reviewed. Finally, the challenges and future development trends of various methods are summarized, providing clues for better practical applications of electrochemical biosensors.

Design and construction of in vitro digestive simulation model

SummaryThe utilisation of in vitro digestive simulation models holds significant importance in the development, quality control, and safety evaluation of functional foods. This review presents an overview of the classification, design, and construction methods of in vitro digestive models while summarising the emerging trends towards miniaturisation and intelligence. Miniaturisation technology enhances the ability of these models to simulate physiological processes within the human digestive system more accurately, thereby improving experiment repeatability and controllability. Intelligent technology further facilitates optimal design, data collection, and analysis for in vitro digestive models.

Evaluation of Bending and Shear properties of Mixed Softwood & Hardwood Cross-Laminated Timbers

The current version of PRG-320 Standard for Performance-Rated Cross-Laminated Timber (CLT) that governs CLT manufacturing and design, limits production to softwood species. As a result, the growing demand for CLT production could strain the supply of softwood lumber in the US within the next decade. The inclusion of hardwood in CLT production alongside softwood could be a potential solution to this problem. This paper investigates the bending and shear test results of three- and five-layer mixed species CLT beams manufactured using various combinations of yellow-poplar and southern pine. The beams were evaluated for bending strength, bending stiffness, shear strength, and shear stiffness, as well as quality control testing of moisture content, specific gravity, resistance to shear by compression loading and resistance to delamination. The experimental values for all CLT groups, adjusted according to the Allowable Stress Design (ASD) to ensure stress limits are not exceeded, were greater than those calculated using the shear analogy method. The only exceptions were bending stiffness values for the groups with all layers of southern pine and those with outer layers of southern pine and inner layers of yellow-poplar (see Table 1 for layups codes), where the differences remained within a minor range of 4%. Although, wood failure percentages in resistance to shear by compression loading fell below the maximum value of 80%, and face delamination percentages in resistance to delamination were above the minimum value of 5% according to the corresponding standards. The mechanical properties of all CLT beams met or exceeded shear analogy values. The test results indicated that yellow-poplar could be a viable alternative to southern pine in the production of CLT due to its similar specific gravity. This suggests that mixed-species CLT can maintain or enhance structural performance while addressing material shortages. Furthermore, the use of yellow-poplar in CLT production promotes sustainable forestry practices, supports resource diversification, and encourages innovation in construction methods. These findings have significant practical implications for the timber and construction industries, contributing to cost efficiency and environmental sustainability.

A novel rigidizable inflatable lunar habitation system: Design concept and material characterization

Constructing lunar bases is crucial as lunar missions progress towards utilization and exploitation. The challenging lunar environment, with its unique characteristics and limited resources, requires special materials, structures, and construction methods. Inflatable structures offer great potential for lunar construction due to their advantages in transportation, stowage, construction, and reliability. This paper proposes a rigidizable inflatable lunar habitat that maintains its shape even after air leakage, enhancing safety, durability, and fixability. The membrane material adapts to different requirements during transportation, construction, and service, achieved through solid-state actuation of shape memory polymer (SMP) for stiffness variation, allowing multiple moves and ground tests. This work comprises three parts: 1) system: design concept and construction processes, 2) material: design and characterization of restraint and rigidization materials, and 3) structure: numerical validation of structural properties. Finite element analysis, based on material models obtained through dynamic mechanical analysis (DMA) and tensile tests, demonstrates the effectiveness of including an SMP rigidizable layer in collapse prevention and improving dynamic performance. This paper proposes a new system, provides material design methods and requirements, and structure validation methods. Findings validate the feasibility of rigidizable inflatable lunar habitats, applicable in extreme environments, also in temporary buildings, space structures, and soft robotics.

Innovative Method for Fixed-Bed Physical Model Construction Applying Modern Materials and Techniques

Innovative Method for Fixed-Bed Physical Model Construction Applying Modern Materials and Techniques

Anisotropic mechanics of cell-elongated structures: Finite element study based on a 3D cellular model

Cell-elongated structures present designable anisotropic behaviors by controlling the ratio and angle of elongation, but the relationship between geometric anisotropy and mechanical anisotropy remains poorly understood. In this study, a construction method based on the 3D Voronoi technique is employed to generate cell-elongated structures with different elongation ratios and angles, and their anisotropic compression behaviors are investigated using a 3D cellular model. The stress–strain curves can be categorized into four stages, including elasticity, initial collapse followed by strain-softening, plateau, and densification, which are accurately described by a statistical constitutive model. Our finding reveals that the mechanical properties and deformation modes of the cell-elongated structures are significantly influenced by the anisotropic angle. At an anisotropic angle of 0°, randomly distributed collapse bands due to shell buckling interact with each other during compression, enhancing the load-carrying and energy-absorbing capacities. Conversely, at 90°, the cells deform primarily through a stable bending mode, leading to reduced stress and a lower Poisson’s ratio. At 45°, collapse bands appear on both sides of the sample with rotation and buckling being the dominant deformation mode, resulting in a sandwich-like structure featuring an uncollapsed central zone due to a combined compression-shear stress state. Compared with the isotropic foam, the structure elongated in thickness direction exhibits a notable increase in impact resistance under a spherical bullet. This work demonstrates the potential to engineer anisotropic cellular materials with tailored mechanical properties and deformation modes through strategic geometric anisotropy design.

Construction and validation of a synthetic phage-displayed nanobody library.

Nanobodies derived from camelids and sharks offer unique advantages in therapeutic applications due to their ability to bind to epitopes that were previously inaccessible. Traditional methods of nanobody development face challenges such as ethical concerns and antigen toxicity. Our study presents a synthetic, phagedisplayed nanobody library using trinucleotide-directed mutagenesis technology, which allows precise amino acid composition in complementarity-determining regions (CDRs), with a focus on CDR3 diversity. This approach avoids common problems such as frameshift mutations and stop codon insertions associated with other synthetic antibody library construction methods. By analyzing FDA-approved nanobodies and Protein Data Bank sequences, we designed sub-libraries with different CDR3 lengths and introduced amino acid substitutions to improve solubility. The validation of our library through the successful isolation of nanobodies against targets such as PD-1, ATXN1 and STAT3 demonstrates a versatile and ethical platform for the development of high specificity and affinity nanobodies and represents a significant advance in biotechnology.

Lentinan-based pH-responsive nanoparticles achieve the combination therapy of tumors

Cancer poses a significant threat to human health, and there is an urgent need for more effective treatments. Combining chemotherapy and immunotherapy is an effective strategy to enhance curative outcomes and holds great potential for widespread application. The natural phytochemical genistein (GEN) exhibits cytotoxicity against tumors and is a potential chemotherapeutic agent. Lentinan (LTN) is a natural polysaccharide with immune-enhancing properties that has been utilized in tumor treatment. This study constructed a pH-responsive nanoparticle GEN@LTN-BDBA with chemotherapy and immunotherapy functions using GEN and LTN. After characterizing the nanoparticles, the molecular mechanism of GEN@LTN-BDBA formation was explored using in-silico simulation. GEN@LTN-BDBA can significantly inhibit the proliferation of A549 and HepG2 cells in vitro. The in vivo experiment results demonstrated that treatment with GEN@LTN-BDBA can significantly reduce tumor cell mass and prevent metastasis. In this nanoparticle, GEN induced oxidative stress and apoptosis of tumor cells. Meanwhile, the released LTN initiated an anti-tumor immune response by promoting dendritic cell maturation and upregulating the expression of costimulatory molecules and major histocompatibility complex. The construction method of GEN@LTN-BDBA can be extended to the preparation of other polysaccharides and hydrophobic chemotherapy molecules, offering a novel strategy to enhance the low efficacy of monotherapy.

Purity skeleton dynamic hypergraph neural network

Recently, in the field of Hypergraph Neural Networks (HGNNs), the effectiveness of dynamic hypergraph construction has been validated, which aims to reduce structural noise within the hypergraph through embeddings. However, the existing dynamic construction methods fail to notice the reduction of information contained in the hypergraphs during dynamic updates. This limitation undermines the quality of hypergraphs. Moreover, dynamic hypergraphs are constructed from graphs. Several key nodes play a crucial role in graph, but they are overlooked in hypergraphs. In this paper, we propose a Purity Skeleton Dynamic Hypergraph Neural Network (PS-DHGNN) to address the above issues. Firstly, we leverage purity skeleton method to dynamically construct hypergraphs via the fusion embeddings of features and topology simultaneously. This method effectively reduces structural noise and prevents the loss of information. Secondly, we employ an incremental training strategy, which implements a batch training strategy based on the importance of nodes. The key nodes, as the skeleton of hypergraph, are still highly valued. In addition, we utilize a novel loss function for learning structure information between hypergraph and graph. We conduct extensive experiments on node classification and clustering tasks, which demonstrate that our PS-DHGNN outperforms state-of-the-art methods. Note on real-world traffic flow datasets, PS-DHGNN demonstrates excellent performance, which is highly meaningful in practice.

Blasting safety criterion of existing high speed railway tunnel over tunnel

Drilling and blasting method is still an important method in the current tunnel excavation construction. Controlling the vibration effect of blasting during construction and its influence on the upper span tunnel is the key problem in tunnel construction. Based on Chongqing Science City tunnel excavation blasting project, combined with the tunnel blasting vibration monitoring and testing, this paper analyzes the propagation attenuation law of tunnel blasting vibration along the rock mass, and studies the load characteristics of the explosion stress wave propagating to the existing high-speed railway tunnel. Considering the influence of the buried depth of the blasting source, a mathematical prediction model of the attenuation law of the upper span existing high-speed railway tunnel caused by tunnel blasting is established. Based on the dynamic finite element numerical calculation method, the influence of blasting vibration on the structure of the existing high-speed railway tunnel under construction is analyzed, and the propagation and attenuation law of blasting vibration along the tunnel contour is studied. Based on the ultimate tensile stress criterion, the ultimate shear stress criterion and the Mohr criterion, and compared with the results obtained from the numerical simulation, the blasting safety criterion model of the existing high-speed railway tunnel over the tunnel is established.

Stepwise Construction and Integration of Ecological Network in Resource-Based Regions: A Case Study on Liaoning Province, China

Ecological networks are an effective strategy to maintain regional ecological security. However, current research on ecological network construction in areas with large-scale resource extraction is limited. Moreover, classic ecological network construction methods do not perform satisfactorily when implemented in heavily damaged mining landscapes. Taking the example of Liaoning Province, China, a framework for stepwise renewal of ecological networks was proposed, which integrates basic ecological sources and other sources that include mining areas. The framework was based on multi-source ecological environment monitoring data, and all potential ecological sources were extracted and screened using an MSPA model and the area threshold method. Further, ecological sources were classified into two types and three levels based on the influence of abandoned mines and the characteristics of ecosystem services in the ecological sources. Ecological corridors were extracted using the MCR model. An ecological corridor optimization process based on combining the gravity model with addition and removal rules of corridors was proposed. The results indicated that the basic ecological network in Liaoning Province included 101 ecological sources and 162 ecological corridors, and the supplementary ecological network included 28 ecological sources and 67 ecological corridors. The ecological sources were divided into two types, and corridors were divided into three types. The basic ecological network exhibited a spatial distribution of discrete connections in the west and close connections in the east. Changes in ecological network topological indicators indicated that a supplementary ecological network strengthened the structural performance of the regional ecological network, expanding spatial coverage, filling hollow areas, and enriching local details of the regional ecological network. Regulation strategies were proposed for ecological sources with different connection modes. The number of ecological sources implementing restrictive development, pattern optimization, and protective development were 101, 12, and 16, respectively. This paper provides a constructing framework of ecological networks adapted for resource-based regions. This method can support decisions for the environmental governance of mines, thus contributing to a balance between resource exploitation and ecological protection in regions.

Devising an approach to the construction of an adapted model of the reconnaissance-fire system functioning

The object of this study is the operational model of a reconnaissance-fire system. The problem that was solved is the lack of an approach to building a model of the functioning of a combat system, in particular a reconnaissance-fire system, which would take into account the influence of all subsystems and include the necessary number of system states. An improved procedure for building an adapted operational model of the reconnaissance-fire system has been proposed. The essence of the improved methodology is the formalization of processes through the definition of system states and intensities of transitions from state to state. The improved procedure is based on the Kolmogorov-Chapman equations and the goal tree construction method. A feature of the improved methodology is the breakdown of the states of the reconnaissance-fire system by hierarchy levels, which allows taking into account more necessary states of the system. The field of practical use of the improved methodology is planning and management processes during the development of action algorithms during combat operations. An adapted operational model of the reconnaissance-fire system has been built. The essence of the model is to determine the probability of the reconnaissance-fire system being in a certain state based on the Chapman-Kolmogorov equations, taking into account the necessary level of detail in the process of its operation. Special feature of the proposed model is that it makes it possible to model by taking into account 39 states of the system with the necessary accuracy both for the system as a whole and separately for subsystems. This is explained by the fact that the test of the adequacy of the model showed that the discrepancy of the results is within the statistical error from 2 to 9 %. The field of application of the adapted operational model of the reconnaissance-fire system is the processes of making a decision on the application of the operation of the intelligence-fire system during hostilities and their management during combat operations.

Addressing the Housing Shortage Gap in Nigeria: An exploration of Dry Construction Method

Due to Nigeria's housing shortage, which has been increasing since the late 20th century and currently stands at 20 million units with a loss rate of 780,000 units annually, Nigeria's construction industry has been under pressure to adopt a modern, timely, and premium construction strategy. This research aims to assess how the dry construction method affects mass housing delivery in developing countries, focusing on Nigeria. This study employed a qualitative research approach, conducting semi-structured interviews with sixteen experts and specialists in dry construction and housing who work for various organisations in Nigeria. The study concluded that, although dry construction is infrequently used in developing countries, it offers significant potential for emerging economies and mortgage companies to ensure prompt housing delivery. By reducing building time and improving housing accessibility, dry construction can address the current challenges of delivering affordable housing in Nigeria. To successfully implement the dry construction method in closing the housing deficit in Nigeria, the research also noted that the government must change its priority beyond direct house development towards creating a conducive framework for the industry. This study presents key stakeholders in the housing sector with the information they need to adopt and implement the dry construction method to close the housing gap, especially in Nigeria, which has received less attention.

A Non-Uniform Grid Graph Convolutional Network for Sea Surface Temperature Prediction

Sea surface temperature (SST) is an important factor in the marine environment and has significant impacts on climate, ecology, and maritime activities. Most existing SST prediction methods consider the ocean as a uniform field and use a uniform grid to predict SST. However, the marine environment is a complex system, and factors such as solar radiation, differences in land and sea thermal properties, and ocean circulation lead to uneven spatial distributions of SSTs. We propose a non-uniform grid construction method based on an SST spatial gradient to encode SST data, as well as a Non-uniform Grid Graph Convolutional Network (NGGCN) model. The NGGCN consists of two spatiotemporal modules, each of which extracts spatial features from the GCN module, captures temporal correlations through the GRU module, and performs feature restoration and output results through the fully connected module. We selected data from the Yellow Sea and Bohai Sea to validate the effectiveness of the NGGCN in predicting SST at different time scales and prediction steps. The results indicate that our model shows a significant improvement in prediction performance compared to other models.

Unveiling Construction Excellence: Strategies, Challenges and Innovations

The construction industry, as a cornerstone of economic development, plays a pivotal role in shaping infrastructure and enhancing the quality of life globally. This thirteenth issue of the Journal of Construction Business and Management presents a collection of research articles by twelve authors from South Africa, Tanzania, the United Kingdom and Zambia. The articles examine the intricacies of procurement strategies, quality management, project management tools, corruption and innovative construction methods. These articles collectively highlight the pathway towards achieving excellence in the construction industry of developing countries, addressing both persistent challenges and emergent solutions.

Strong barriers for weighted quasilinear equations

In potential theory, use of barriers is one of the most important techniques. We construct strong barriers for weighted quasilinear elliptic operators. There are two applications: (i) solvability of Poisson-type equations with boundary singular data, and (ii) a geometric version of Hardy inequality. Our construction method can be applied to a general class of divergence form elliptic operators on domains with rough boundary.

Numerical prediction of ground-borne vibrations due to continuous vibratory driving of circular closed-ended piles

Various types of pile driving work may induce high-intensity ground-borne vibrations. Predicting vibration intensity before adopting mitigation measures is vital for minimizing the impact of vibration on nearby structures and occupants. Vibratory pile driving is a commonly applied foundation construction method. However, numerical simulation models for ground vibrations during a complete process of vibratory driving have rarely been studied. This study introduces an axisymmetric finite element model that utilizes the arbitrary Lagrangian-Eulerian technique to simulate the continuous vibratory driving of a circular closed-ended pile penetrating from the ground surface to a target depth. The model validity was confirmed by assessing the calculated ground vibrations against the findings documented in earlier research. The results showed that the critical penetration depth of piles, at which the maximum peak particle velocity (PPV) occurs, varied with the radial distance and depth of points of interest, contradicting a common preconception. Moreover, the maximum PPV did not always occur on the ground surface across all radial distances. Parametric analysis revealed that an increase in the soil cohesion strength, pile diameter, or soil-pile friction, or a decrease in the driving frequency or soil damping ratio would increase ground vibrations due to vibratory pile driving.

Reticular Chemistry and In Situ "One-Pot" Strategy: A Dream Combination to Construct Metal-Organic Frameworks.

The establishment of reticular chemistry has significantly facilitated the development of porous materials, especially for metal-organic frameworks (MOFs). On the other hand, as an alternative approach, in situ "one-pot" strategy has been explored as a promising approach to constructing MOFs, in which the synthesis of organic linkers and the sequential construction of MOFs are integrated into one solvothermal condition. This strategy can efficiently avoid the limitations faced in the traditional construction method, such as time-consuming organic synthesis and multiple separation and purification. Herein, inspired by the reaction of aldehydes and o-phenylenediamine and deep structural analysis of UiO-68, a series of tetra-, hexa-, and octa-topic carboxylic acids are synthesized using 2',3'-diamino-[1,1':4',1'"-terphenyl]-4,4'"-dicarboxylic acid and di-, tri-, and tetra-topic aldehydes as precursor. Then nine multicarboxylate-based zirconium MOFs (Zr-MOFs) are successfully constructed via the combination of reticular chemistry and in situ "one-pot" strategy. The resultant Zr-MOFs can be regarded as the partial face decoration of UiO-68. More importantly, the emission properties of resultant Zr-MOFs can be well controlled using aldehydes with tunable electronic structures. This work provides a new path to rational design and construction of porous materials with specific structures guided by reticular chemistry and conducted using in situ "one-pot" strategy.

Mechanistic Analysis of Reflective Cracking Potential in Electrified Pavement with Inductive Charging System

Electrified pavements with inductive charging systems provide an innovative way of providing continuous wireless power transfer to electric vehicles (EVs). Electrified pavements have unique construction methods, resulting in different mechanical and thermodynamic characteristics from traditional pavements. This study aimed to investigate the mechanistic design of electrified pavements to mitigate thermal-induced reflective cracking due to the inclusion of concrete slabs with inductive charging units (CUs) under an asphalt surface layer. Finite element (FE) models were developed to analyze the temperature profiles, pavement responses, and crack potential in electrified pavements. The fatigue model and Paris’ law were utilized to evaluate crack initiation and propagation for different pavement designs. Within the allowable range for sufficient wireless charging efficiency, increasing the surface layer thickness had a noticeable benefit on mitigating crack initiation and propagation. The results indicate that increasing the asphalt surface layer thickness by 20 mm can delay crack initiation and propagation, resulting in a two to threefold increase in the number of cycles needed to reach the same crack length. Reflective cracking can also be retarded by the optimized design of the charging unit. Increasing the concrete slab thickness from 100 mm to 180 mm resulted in an approximately 20% increase in the number of cycles to reach the same crack length. Reducing the slab width and length (shortening joint spacing) could also effectively reduce the reflective cracking potential, with the slab length having a more significant influence. These findings highlight the importance of balancing charging efficiency and structural durability in the design of electrified pavements.