Hasil untuk "Structural engineering (General)"

Xiao-Peng Niu, Run‐Zi Wang, D. Liao et al.

Abstract Turbine bladed disks normally operate under complex loadings coupling with uncertainties originate from multiple sources, including material variability, load variation and geometrical uncertainty. The influence of these uncertainties on mechanical response of engineering components are critical for their fatigue assessment and reliability evaluation. In this work, a general framework for fatigue reliability analysis is developed by coupling the Latin hypercube sampling with FE analysis to describe the combined effects of multi-source uncertainties. Fatigue reliability analysis of a full-scale bladed disk under multi-source uncertainties was performed as well as sensitivity analysis for fatigue design. In order to describe the manufacturing errors or tolerances, random dimensions are inputted. Comparing the predicted fatigue lifetime distributions with/without geometrical uncertainty, it shows that geometrical uncertainty matters in structural fatigue reliability. Particularly, sensitivity analysis indicates that the geometrical uncertainty exerts more critical influences on the fatigue lifetime and reliability of the turbine bladed disk than others. The sensitivity factors of three typical dimensions emerges the influence of designed sizes and dimensional tolerances on the failure probability, which provides a reference for engineering design.

Chong Hu, Yun-Ke Bai, Miao Hou et al.

Defect engineering of enzyme-MOF composites by microfluidics engenders high enzymatic activity. Mimicking the cellular environment, metal-organic frameworks (MOFs) are promising for encapsulating enzymes for general applications in environments often unfavorable for native enzymes. Markedly different from previous researches based on bulk solution synthesis, here, we report the synthesis of enzyme-embedded MOFs in a microfluidic laminar flow. The continuously changed concentrations of MOF precursors in the gradient mixing on-chip resulted in structural defects in products. This defect-generating phenomenon enables multimodal pore size distribution in MOFs and therefore allows improved access of substrates to encapsulated enzymes while maintaining the protection to the enzymes. Thus, the as-produced enzyme-MOF composites showed much higher (~one order of magnitude) biological activity than those from conventional bulk solution synthesis. This work suggests that while microfluidic flow synthesis is currently underexplored, it is a promising strategy in producing highly active enzyme-MOF composites.

Xiuchen Xu, Zhen Wang, Zhaoyan Sheng et al.

Portable concrete barriers (PCBs) are modular structures widely used to separate traffic lanes from construction zones. However, these barriers often exhibit insufficient structural safety to effectively block intruding vehicles, leading to severe casualties. Appropriate structural design and experimental verification are required to prevent damage to the PCB structure. Existing domestic specifications lack explicit provisions regarding the structural design and load-bearing capacity of PCBs, presenting a critical bottleneck for the engineering application of temporary traffic barriers. To mitigate this limitation, a novel PCB was developed featuring a pre-embedded rectangular steel tube and I-beam joint, coupled with a single-slope cross-section (1200 mm in height), to satisfy the SB-level safety performance criteria specified in relevant standards. Distinct from conventional finite element simulation approaches, two full-scale vehicle impact tests were subsequently performed to verify the structural safety of the barrier. Experimental results demonstrate that the newly designed barrier can withstand vehicle impacts, meeting the SB protection level, with its containment, redirection, and energy absorption capabilities complying with relevant specification criteria. This study is anticipated to establish a foundational dataset for subsequent research in the field.

Jiajie Li, Yangxue Yao, Yun Wang et al.

Jinlong Li, Xin Jia, Lijun Yin

ABSTRACT Hydrogels are a series of soft and wet materials with three dimensions of crosslinked networks. Hydrogels have attracted great attention due to their diverse functional properties, and their wide range of applications, such as in soft robots and actuators, stretched electronic devices, tissue engineering materials, controlled-release drug delivery vehicles, biomedicine materials, food science, and (bio)sensors. In general, there are four core concerns in hydrogel science, including the polymer source, structure fabrication, gel function, and gel applications. According to the logic that the “structure determines function”, it is believed that rational design of structures can effectively regulate the functions and applications of hydrogels. Hence, in the current review, “structure” as the core topic will be highly regarded, and the crosslinking mechanisms and structural diversity of hydrogels are comprehensively summarized. Additionally, hydrogels also show their great application potential in food science. Hence, the current review also pays more attention to the application of hydrogels in food nutrition and health, food engineering and processing, and food safety. It is whished that this review not only serves as a reference for improving the comprehensive understanding of the structural design of hydrogels but also provides a forward-looking idea for hydrogel applications in food science. Graphical abstract Graphical Abstract

O. Gaidai, Yu Cao, Y. Xing et al.

Safety and reliability are essential engineering concerns for energy-harvesting installations. In the case of the piezoelectric galloping energy harvester, there is a risk that excessive wake galloping may lead to instability, overload, and thus damage. With this in mind, this paper studies bivariate statistics of the extreme, experimental galloping energy harvester dynamic response under realistic environmental conditions. The bivariate statistics were extracted from experimental wind tunnel results, specifically for the voltage-force data set. Authors advocate a novel general-purpose reliability approach that may be applied to a wide range of dynamic systems, including micro-machines. Both experimental and numerically simulated dynamic responses can be used as input for the suggested structural reliability analysis. The statistical analysis proposed in this study may be used at the design stage, supplying proper characteristic values and safeguarding the dynamic system from overload, thus extending the machine’s lifetime. This work introduces a novel bivariate technique for reliability analysis instead of the more general univariate design approaches.

Asset Kyzdarbekova, Azhar Nurmagambetova, Aliya Nurgaliyeva et al.

This study investigates the pivotal role of environmental auditing in fostering green economic growth in Kazakhstan, providing a distinctive perspective through the integration of qualitative and quantitative methodologies. By employing a descriptive research approach and leveraging structural equation modeling (SEM) analysis, the research explores Kazakhstan's environmental policies and empirical data from governmental and non-governmental reports, statistical audit findings, and academic literature. The study unveils significant insights; environmental auditing not only enhances resource efficiency and curtails pollution but also bolsters economic sustainability. Crucially, it identifies barriers such as ambiguous legislative frameworks and a shortage of skilled auditors, while proposing actionable opportunities like aligning policies with international standards and initiating capacity-building programs. Unlike prior research, this study uniquely contributes to the field by offering a comprehensive examination of environmental auditing's multifaceted impact within Kazakhstan's unique socio-economic and ecological landscape. It bridges the gap between policy analysis and empirical validation, providing targeted recommendations for enhancing the effectiveness of environmental audits. These include legislative reforms, structured auditor training initiatives, and economic incentives aimed at fostering sustainable business practices. The findings underscore the indispensable role of environmental auditing as a cornerstone for Kazakhstan's transition to a green economy.

Danielle Wiles, James Roest, Bhuvana Shanbhag et al.

Terpenoids are the largest and most diverse family of natural products. Volatile terpenes from Cannabis sativa are crucial in flavours, fragrances, and pharmaceuticals due to their unique odours and biological activities, including antimalarial, antibacterial, and insecticidal properties. Their synthesis is catalysed by terpene synthase (TPS) enzymes, which perform cyclisation and rearrangement reactions of over 55,000 distinct terpene compounds. However, low catalytic efficiency of C. sativa TPSs limits their use in large-scale commercial production. The complex biochemistry of these reactions is not well understood due to limited enzyme structure information. To address this, we have developed an integrated platform for the systematic expression, purification, enzymatic characterisation, and crystallisation of TPS enzymes from C. sativa. This workflow combines kinetic, thermostability, and structural analyses with a data-mining-informed crystallisation screen that enabled the production of diffraction-quality crystals. As a demonstration of the platform’s utility, ten C. sativa TPS enzymes were functionally characterised, revealing turnover rates (kcat) ranging from 0.0011 to 0.0204 s−1 and diverse substrate specificities, with each enzyme producing a distinct product profile, highlighting the need for systematic characterisation of C. sativa terpene biosynthesis. Our findings provide a framework for the structural and functional study of C. sativa TPSs. The developed platform sets the stage for future metabolic engineering aimed at optimising terpene production for pharmaceutical, pest management, and synthetic biology applications.

Aslı Semerci, Celine AlBalaa, Brian Corrie et al.

Recent advancements in sequencing technologies have led to an exponential increase in adaptive immune receptor repertoire (AIRR) data. These receptors, crucial to the adaptive immune system, are believed to have strong potential for diagnostic applications. The immune repertoires represent a wealth of data, creating a growing demand for robust computational methods to analyze and interpret this vast amount of information.In this review, we examine the application of machine learning algorithms for the classification and analysis of AIRR-seq data for different diagnostic applications. We provide a high-level division of current approaches based on their focus on repertoire-level or sequence-level features. We provide an overview of the current state of public AIRR data sets available for model training. Finally, we briefly highlight what lessons can be learned from successful AIRR diagnostic approaches and what hurdles still must be overcome.

Hang-Fei Liu, Xiaohua Huang, Guoliang Pang et al.

Assessing the current forces exerted on a semi-submersible truss fish cage is crucial for understanding drag force distribution and ensuring the structural safety. The present study employs computational fluid dynamics (CFD) methods and porous media theory to predict the drag forces on a semi-submersible truss fish cage, providing a detailed description of the magnitude and distribution patterns of drag forces on the plane nets, pontoons, columns, and braces. Results indicate that the side plane nets bear the highest forces, contributing 24.3% of the total force. The pontoons and thick columns are the next most affected, contributing 18.7% and 13.8% of the total force, respectively, while the middle cross braces bear the least force at 3.7%. A decrease in current speed leads to reduced drag forces on the downstream side plane nets, columns, pontoons, and braces. However, the projected area of each component in the current direction is a critical factor influencing changes in drag forces. Additionally, the torque generated by the drag forces on the semi-submersible truss fish cage is examined. Center position of the torque can alter the torque direction exerted on the truss net cage, and the transition occurs between 18 cm and 19 cm. The present investigation provides a comprehensive evaluation of the drag force distribution on the semi-submersible truss fish cage, which is significant practical engineering implications.

F. Praetorius, P. J. Leung, Maxx H. Tessmer et al.

Proteins that switch between two structural states as a function of environmental stimuli are widespread in nature. These proteins structurally transduce biochemical information in a manner analogous to how transistors control information flow in computing devices. Engineering challenges ranging from biological computing devices to molecular motors require such two-state switches, but designing these is an unsolved problem as it requires sculpting an energy landscape with two low-energy but structurally distinct conformations that can be modulated by external inputs. Here we describe a general design approach for creating “hinge” proteins that populate one distinct state in the absence of ligand and a second designed state in the presence of ligand. X-ray crystallography, electron microscopy, and double electron-electron resonance spectroscopy demonstrate that despite the significant structural differences, the two states are designed with atomic level accuracy. The kinetics and thermodynamics of effector binding can be finely tuned by modulating the free energy differences between the two states; when this difference becomes sufficiently small, we obtain bistable proteins that populate both states in the absence of effector, but collapse to a single state upon effector addition. Like the transistor, these switches now enable the design of a wide array of molecular information processing systems.

M. Shinozuka

Yi Zhu, E. Filipov

Existing Civil Engineering structures have limited capability to adapt their configurations for new functions, non-stationary environments, or future reuse. Although origami principles provide capabilities of dense packaging and reconfiguration, existing origami systems have not achieved deployable metre-scale structures that can support large loads. Here, we established modular and uniformly thick origami-inspired structures that can deploy into metre-scale structures, adapt into different shapes, and carry remarkably large loads. This work first derives general conditions for degree-N origami vertices to be flat foldable, developable, and uniformly thick, and uses these conditions to create the proposed origami-inspired structures. We then show that these origami-inspired structures can utilize high modularity for rapid repair and adaptability of shapes and functions; can harness multi-path folding motions to reconfigure between storage and structural states; and can exploit uniform thickness to carry large loads. We believe concepts of modular and uniformly thick origami-inspired structures will challenge traditional practice in Civil Engineering by enabling large-scale, adaptable, deployable, and load-carrying structures, and offer broader applications in aerospace systems, space habitats, robotics, and more. In this work, authors establish general conditions for flat foldability, developability, and uniform thickness in origami-inspired structures and introduce a large-scale modular design capable of deploying into meter-scale configurations, adapting to various shapes, and supporting significant loads.

Q. Xie, W. Bu, S. Bhatia et al.

Shiva Abrifam, Amirali Zad, Maryam Yazdi et al.

Anchors are tensile elements that resist external tensile forces by attaching to structures and being embedded at an optimal depth in the ground. Various types of anchors have been developed for stabilizing both offshore and onshore environments. This study focuses on the experimental examination of a novel type of mechanically expandable plate anchors capable of opening in soil. The impact of various factors including the division of the surface within the plates, pull-out speed, spacing between plates, and soil density on the ultimate pull-out capacity of expandable plate anchors embedded in a sand bed has been explored through physical modeling. To analyze the formation of rupture wedges and the mobilization of the soil volume resting on the plates, particle image velocimetry was employed. Findings indicate that maintaining the plate area constant and altering the area distribution from a scenario of equal-area two-plate anchors to one with greater area allocation on the lower plate enhances the anchor's pull-out capacity by 1.5 times. Furthermore, assessing the functionality of the expandable double-plate anchor across varying pull-out speeds reveals minimal influence of pull-out speed on the pull-out capacity in sandy soils. Among the examined speeds, pulling out the anchors at rates of 10 and 30 mm/min, respectively, in soils of low and high relative densities yielded the highest pull-out forces.

Surya Tripathi, Carlos Geert Pieter Voogdt, Stefan Oliver Bassler et al.

Summary: Randomly barcoded transposon mutant libraries are powerful tools for studying gene function and organization, assessing gene essentiality and pathways, discovering potential therapeutic targets, and understanding the physiology of gut bacteria and their interactions with the host. However, construction of high-quality libraries with uniform representation can be challenging. In this review, we survey various strategies for barcoded library construction, including transposition systems, methods of transposon delivery, optimal library size, and transconjugant selection schemes. We discuss the advantages and limitations of each approach, as well as factors to consider when selecting a strategy. In addition, we highlight experimental and computational advances in arraying condensed libraries from mutant pools. We focus on examples of successful library construction in gut bacteria and their application to gene function studies and drug discovery. Given the need for understanding gene function and organization in gut bacteria, we provide a comprehensive guide for researchers to construct randomly barcoded transposon mutant libraries.

H. Afshari, W. Hare, S. Tesfamariam

Abstract Engineering design problems are often multi-objective in nature, which means trade-offs are required between conflicting objectives. In this study, we examine the multi-objective algorithms for the optimal design of reinforced concrete structures. We begin with a review of multi-objective optimization approaches in general and then present a more focused review on multi-objective optimization of reinforced concrete structures. We note that the existing literature uses metaheuristic algorithms as the most common approaches to solve the multi-objective optimization problems. Other efficient approaches, such as derivative-free optimization and gradient-based methods, are often ignored in structural engineering discipline. This paper presents a multi-objective model for the optimal design of reinforced concrete beams where the optimal solution is interested in trade-off between cost and deflection. We then examine the efficiency of six established multi-objective optimization algorithms, including one method based on purely random point selection, on the design problem. Ranking and consistency of the result reveals a derivative-free optimization algorithm as the most efficient one.

Narek Galustanian, Alaa El-Sisi, Asmaa Amer et al.

The need for openings in RC structures has increased, but their presence significantly affects the performance and strength of the structures. While small openings can be managed with additional reinforcement, dealing with large openings in reinforced or pre-stressed concrete members is challenging due to the lack of technical information and specific guidelines. This research provides an up-to-date overview of RC beam–column joints that incorporate web openings and evaluates appropriate strengthening methods. The research discusses the classification of openings in RC beams, considering factors such as size and shape. Additionally, it examines the failure modes of RC beams in relation to flexural and shear behavior when web openings are present. The research also provides a comprehensive review of various strengthening techniques, outlining their advantages and disadvantages. In conclusion, larger openings in beams result in reduced strength, while increasing loads lead to higher deflection, strain, and cracking until failure. Openings are classified as small or large based on their impact on beam behavior. Multiple smaller openings are preferred over a single large opening when size becomes excessive. Optimal placement is in the middle of the section to ensure adequate concrete coverage for the chords. Sufficient concrete and depth are essential for ultimate compression during bending and effective shear reinforcement.

Bixia Zhou, Xulei Jiang, Xinxin Zhou et al.

Abstract Currently, the clinical treatment of critical bone defects attributed to various causes remains a great challenge, and repairing these defects with synthetic bone substitutes is the most common strategy. In general, tissue engineering materials that mimic the structural, mechanical and biological properties of natural bone have been extensively applied to fill bone defects and promote in situ bone regeneration. Hydrogels with extracellular matrix (ECM)-like properties are common tissue engineering materials, among which methacrylate-based gelatin (GelMA) hydrogels are widely used because of their tunable mechanical properties, excellent photocrosslinking capability and good biocompatibility. Owing to their lack of osteogenic activity, however, GelMA hydrogels are combined with other types of materials with osteogenic activities to improve the osteogenic capability of the current composites. There are three main aspects to consider when enhancing the bone regenerative performance of composite materials: osteoconductivity, vascularization and osteoinduction. Bioceramics, bioglass, biomimetic scaffolds, inorganic ions, bionic periosteum, growth factors and two-dimensional (2D) nanomaterials have been applied in various combinations to achieve enhanced osteogenic and bone regeneration activities. Three-dimensional (3D)-bioprinted scaffolds are a popular research topic in bone tissue engineering (BTE), and printed and customized scaffolds are suitable for restoring large irregular bone defects due to their shape and structural tunability, enhanced mechanical properties, and good biocompatibility. Herein, the recent progress in research on GelMA-based composite hydrogel scaffolds as multifunctional platforms for restoring critical bone defects in plastic or orthopedic clinics is systematically reviewed and summarized. These strategies pave the way for the design of biomimetic bone substitutes for effective bone reconstruction with good biosafety. Graphical Abstract This review provides novel insights into the development and current trends of research on GelMA-based hydrogels as effective bone tissue engineering (BTE) scaffolds for correcting bone defects, and these contents are summarized and emphasized from various perspectives (osteoconductivity, vascularization, osteoinduction and 3D-bioprinting). In addition, advantages and deficiencies of GelMA-based bone substitutes used for bone regeneration are put forward, and corresponding improvement measures are presented prior to their clinical application in near future (created with BioRender.com).

Jesus Donaire-Avila, Amadeo Benavent-Climent, Fabrizio Mollaioli

It is widely accepted in the seismic design of buildings a certain level of damage under moderate or severe seismic actions but preventing the damage concentration in them. On the other hand, the energy-based design methodology proposes an optimum strength distribution for designing the structure of the building aimed at achieving an approximated even distribution of the damage—energy dissipated by plastic deformations—under seismic actions. Different approaches for the optimum strength distribution have been proposed in both existing literature and standards. Most of them were formulated from the results obtained in non-linear numeric evaluations of elastic-perfectly plastic (EPP) structures, such as the findings proposed recently by the authors of this study. However, studies on the optimum strength distributions of reinforced concrete (RC) structures are scarce. The present study sheds light on this issue. Accordingly, the structures of four prototype buildings with 3, 6, 9, and 12 stories were designed through an energy-based method by using five approaches for the optimum strength distribution: those proposed by the authors and two others from the literature and standards. Then, different prototypes of the structures arose considering the different approaches for the optimum strength distribution, two soil classes (dense and medium dense), and two ductility levels (low and high). Such prototype structures were subjected to two sets of far-field ground motion records by using three different constitutive models for the shear force-interstory drift relationship: EPP, Clough model, and Modified Clough model. The first characterizes the steel structures and the rest are typical for RC structures. A complete analysis was carried out to obtain the distribution of damage for EPP and RC structures, their deviations with respect to the “ideal” even distribution of damage, and the possible damage concentration on specific stories. RC structures showed a higher dispersion for the distribution of damage than EPP structures although those designed with the optimum strength distributions proposed by the authors showed the lowest values in the order of those obtained with EPP structures designed with optimum strength distributions proposed in the literature.