Line Structure Research Articles

Analysis and control of the causes of the uplift of the invert of deep tunnels

When traversing a complex and fractured geological formation, a deep-buried highway tunnel in Yunnan Province encountered a significant uplift problem in the invert. The causes of the tunnel’s uplifted section were analyzed through on-site observations and monitoring of the lining structure’s deformation, combined with numerical simulation methods. The results indicate that the primary factors leading to the invert uplift are the softening of the surrounding rock at the invert base due to water seepage and the high water pressure in the fractured zone. The softening of the surrounding rock is crucial to the safety of the inverted uplift structure. Based on the tunnel’s engineering characteristics and the causes of the invert uplift, remediation measures such as “enhancing the drainage system, grouting with steel flower pipes, and demolishing and replacing the invert” were adopted. These measures effectively controlled the invert uplift. After the remediation, the convergence rate of the secondary lining decreased, and the deformation stabilized, indicating that the invert uplift remediation plan was reasonable and effective

A novel two-layer composite geomembrane lining structure to mitigate frost damage in cold-region canals: Model test and numerical simulation

The canal is crucial for water diversion projects, but it is susceptible to frost damage. To address this, a two-layer composite geomembrane lining structure (TLCGLS) was proposed that regulates the interaction between canal lining and frozen soil. Model tests were conducted to investigate its anti-frost heave effectiveness. Considering the interaction among the lining, two-layer composite geomembranes (TLCGs), and frozen soil, a canal frost heave model with heat-water-mechanical coupling was developed. The influence of canal cross-section shapes and TLCGs arrangements on anti-frost heave performance and mechanism of TLCGLS were discussed. Results show that TLCGLS reduces uneven frost heave degree and compressive/tensile strains of the lining by 35%, 29%, and 28% respectively. During melting, it rapidly reduces frost heave, tangential deformation, and strain with minimal residual effects. TLCGLS demonstrates strong resetting ability and excellent anti-frost heave performance. It is particular suitable for arc-bottomed trapezoidal canals. However, excessive reduction in friction between TLCGs weakens arching effect of the bottom lining, increasing tensile stress and safety risks. TLCGLS with geomembrane-geotextile contact exhibits superior anti-frost heave performance, mitigating compressive stress by over 50% while meeting design requirements for tensile stress. These findings provide a theoretical basis and technical solution for mitigating frost damage in canals.

Numerical Investigation of the Long-Term Service Performance of Subsea Tunnel Lining Structure Considering Ion Erosion Deterioration

Ion erosion has a significant impact on the long-term service performance of lining structures in the subsea tunnel and seriously affects its sustainability. Indoor tests are usually used to study the erosion behavior of lining concrete specimens to reveal the degradation pattern of ion erosion. However, the long-term service performance of lining structures under ion erosion is rarely considered in the industry. In this study, the long-term deterioration characteristics of concrete specimens and subsea tunnel linings are analyzed by using numerical investigations. The long-term diffusion patterns of erosion ions in concrete specimens are evaluated. The effects of ion erosion and water pressure on the stress, deformation, and damage characteristics of the lining structure are examined. The numerical results show that solution concentrations and concrete grades have a significant influence on the ion diffusion in concrete specimens. As the erosion time increases, the rate of ion diffusion gradually decreases due to the decrease in the concentration difference between the inside and outside of the concrete. The service time T has a significant effect on the depth and rate of ion erosion. When T is 10, 50, and 100 years, the depth of ion erosion reaches 25, 63, and 84 mm, respectively, showing a nonlinear increase. As the depth of ion erosion increases, the characteristic parameters reflecting the long-term performance of the lining structure will increase. The maximum tensile stress is 0.98 MPa, and the maximum displacement is 1.59 cm, both of which occur at the arch crown. Disregarding the effects of ion erosion and water pressure, the vertical displacements of the lining structure within the first two years under low loads account for more than 97% of the 100-year displacements. Both ion erosion and water pressure exacerbate the damage deterioration of the lining, in which ion erosion significantly increases the maximum tensile stress of the lining, with a maximum enhancement of 326.09%, and water pressure significantly enlarges the maximum compressive stress of the lining, with a maximum enhancement of 53.23%. However, with increasing depths of ion erosion, the high water pressure will reduce the maximum tensile stress. This study can lay the foundation for further research on the long-term stability of the lining under complex erosion environments.

Internal Crisis Communication in Hospitals the Choice of Communication Channels and Its Impact on Effectiveness

ABSTRACTThe COVID‐19 pandemic has highlighted the need for effective internal crisis communication (ICC) in hospitals. However, only little is known about how the choice of communication channels influences the effectiveness of ICC. Our case study offers novel insights into this relationship. We performed an in‐depth analysis of ICC during the COVID‐19 pandemic at a Norwegian tertiary public hospital. We conducted 22 in‐depth interviews with stakeholders from various hierarchical levels who actively participated in ICC. We mapped the relationships of the actors involved in ICC and performed a social network analysis. The emergency reorganization of the hospital made ICC processes more complex compared to the ordinary line structure of communication, and on lower hierarchical levels several redundant (and not necessarily officially approved) communication channels were used. Moreover, we found that the effectiveness of ICC was reduced by communication channels with speed and bandwidth limits. In contrast, communication channels with a high capability to transmit contextualized information improved the effectiveness of ICC. Since our case hospital shares common characteristics with many other tertiary public hospitals, including fragmentation of responsibilities during crisis response, we use our results as a basis for recommending appropriate communication channels and avoiding a decoupling of ICC between hierarchical levels and professions.

Impacts of an environmental ototoxic pollutant on fish fighting behaviors.

Numerous environmental pollutants exhibit ototoxicity and cause damage to the lateral line structures in fish, including the neuromast and its hair cells. The lateral line is used to detect hydrodynamic changes and is thought to play a significant role in aggressive interactions. Fighting behaviors in fish are crucial for establishing social hierarchy and obtaining limited resources. In this study, we ablated the function of hair cells using a commonly used ototoxin, neomycin, to evaluate the impact of this ototoxic pollutant on fighting behavior through damaging the lateral line. Our results showed that the number of wins and the duration of dyadic fight behavior decreased in zebrafish with lateral line ablation. These zebrafish also exhibited increased anxiety and biting frequencies. On the other hand, social preferences and fitness were not affected in lateral line-ablated zebrafish. In conclusion, the lateral line mechanosensory system is crucial for fish to gather sufficient information and make correct decisions during conflicts and fighting behaviors. Impairment of hair cell function can affect aggressive behaviors and decision-making in fish, subtly altering their behavioral patterns and leading to significant impacts on the aquatic ecosystem.

Engineering method for quantifying the coupling effect of transmission tower-line system under strong winds

For transmission tower-line (TL) systems, the coupling effect between line cables and towers under strong winds is significant. This paper presents a method to quantify the coupling effect. Assuming that effective separation of line cables and towers is attainable, this work transforms the coupling effect into the transferred load from the line cable to the target tower, the coupling participation mass of the line cable, and the additional damping. The effective separation conditions are defined through an optimization method minimizing the residual errors of the wind-induced response and dynamic characteristics between the separated bodies and the TL system. A typical TL system is considered and analyzed for its structural dynamic characteristics and wind-induced response. Particularly, the quantities associated with the coupling effect of the TL system are estimated. It reveals that the transferred dynamic load component parallel to the line cable which is overlooked in current codes is significant and highly sensitive to the separation boundary conditions of line cables. Furthermore, the coupling participation mass of the conductor is more prominent than that of the ground wire. The proposed method is feasible for quantifying the TL coupling effect and incorporating it into the wind-induced response analysis of transmission line structures.

Causes, influencing factors, and prediction modeling of crystallization blockage of tunnel drainage blind pipe in non-karst area

The complete functioning of the tunnel drainage system is critical in ensuring the stability of tunnel lining structures and safe operations. Therefore, the issue of crystalline blockage in the tunnel drainage system needs to be solved urgently. In this study, the formation mechanism of tunnel crystallization defects in non-karst areas was investigated, and the influencing factors of calcium ion dissolution of shotcrete were evaluated by field investigation. Also, the sampling analysis was carried out to determine the ionic composition and content of seepage water. The source and composition of crystallites were determined by X-ray diffraction (XRD), inductively coupled plasma mass spectrometry (ICP-MS), and field-emission scanning electron microscope (SEM). The mechanism and role of pH in CaCO3 crystal formation were explored by simulation using MINTEQ 3.1 software. In addition, a new accelerated leaching test model was developed to examine the flow rate, concentration, and temperature effects on Ca2+ leaching rate in shotcrete. The analysis of water quality and crystal showed that the white and yellow crystals in the tunnel were calcite-type calcium carbonate, occurring as a paste. Micro-morphology of new crystals showed densely-distributed prismatic spherical and scaly crystal structure. The other parts were irregular squares, spindles, rhombuses, and other forms of scattered distribution. The Ca2+ originated from the shotcrete. The accelerated leaching test demonstrated that the optimal test conditions for the leaching rate of Ca2+ in shotcrete were a flow rate of 4 L/min, concentration of 5 mol/L, and temperature of 20 °C. Based on these findings, the prediction model of the Ca2+ leaching rate of shotcrete is established.

Acoustic Tunnel Lining Void Detection: Modeling and Instrument System Development

The detachment of railway tunnel lining constitutes a grave danger to train operation safety and drastically curtails the tunnel’s service life. This study endeavors to efficiently detect the void defects in railway tunnel lining by creating a finite element model of tunnel lining structures. Utilizing this model, the study simulates the nonlinear acoustic wave propagation cloud maps for three representative tunnel lining structures: void-free, air void, and water void. This facilitates a thorough examination of the acoustic signal characteristics in the wavefield, time domain, and frequency domain. To satisfy the precision and efficiency demands of tunnel lining void detection, this study has devised and developed a portable acoustic detector that incorporates automatic analysis and processing capabilities and is furnished with a high-performance rare-earth magneto-strictive acoustic excitation device. This detection system can swiftly detect and assess typical void defects in tunnel lining. To further validate the effectiveness of this system, this study conducted lining defect detection in the Pingdao Railway Tunnel in the eastern Qinling Mountains. The test results show that the detection rate of this system for both air-filled and water-filled voids with a width of 1 m reached 100%, demonstrating its extremely high application value.

Compact and ultra-wideband high-efficiency rectifier using asymmetric coupled-line impedance transformer

Abstract This paper presents a compact and ultra-wideband high-efficiency microwave rectifier for wireless power transmission (WPT) applications. The input-matching-network utilizes a compact asymmetric coupled transmission line structure, contributing to wideband performance. The rectifier adopts a voltage-doubler topology, resulting in a smooth input impedance across a wide bandwidth. The working principle of the asymmetric coupled transmission line matching network is analyzed. Simulation and measurement are conducted on the proposed rectifier. The fabricated prototype demonstrates a wide bandwidth of 162.5% (0.3–2.9 GHz with the power conversion efficiency (PCE) exceeding 60% at an input power of 18 dBm. Even at an input power of 10 dBm, the measured PCE remains above 50% over the working band. The proposed ultra-wideband rectifier shows promising potential for WPT applications including wireless powering of low-power electronic devices and sensors.

The structuring of a (semi) agile-based organization: product orientation in a state agency

Purpose The purpose of the paper is to analyze how a change towards product orientation based on an agile approach challenges, contrasts and/or coexists with other principles of organization and grouping, such as development projects, the existing hierarchical line structure and process management. Design/methodology/approach This is a case study of one organization, based on an explorative appoach. Findings Taking the competing dimension of coordination and principles of grouping as the starting point, this study identify, describe and analyze the tensions that result from the introduction of product organization. The product initiative has met many obstacles and tensions along four dimensions: Process, line, information technology units and development projects. For each of these dimensions a number of challenges have been identified, that contribute to increased complexity in the organization. Research limitations/implications A limitation of the study is that the findings cannot be generalized to other organizations. Practical implications A practical implication of the study is that product organization triggers tensions with other principles of organizations and grouping. Originality/value This study mainly contributes to the knowledge of agile management and agile organization, identifying and theorizing challenges that have been neglected and/or poorly understood both in the popular literature and in organizational research. This is particularly the case in the public sector. This study is also relevant to the domain of multidimensional structures, adding an understanding of the novel opportunities and challenges of product- and agile-based grouping of activities in an organization.

Optimization of Wiring Harness Logistics Flow in the Automotive Industry

This paper presents a compelling argument for optimizing the logistics flow of wiring harnesses within the automotive industry to address the rising production demands of vehicle manufacturers. It introduces an innovative assembly line structure specifically designed to boost efficiency and enhance responsiveness to client needs. Drawing from data gathered from an actual assembly line dedicated to producing engine harnesses for K9K engines, this study offers a practical and impactful foundation for its proposed optimization strategies. The new assembly structure effectively merges the benefits of a dynamic line—which emphasizes efficient space utilization and flexibility—with the strengths of a rotary line, particularly in light of the increasing complexity associated with harness production. The paper features a mathematical model that calculates cycle times for workstations within this new system architecture, optimizing the entire production process. Moreover, it illustrates how advanced modeling, simulation, and optimization techniques using WITNESS Horizon Version Release 25.0 can identify necessary adjustments for achieving optimal assembly line balance. Additionally, this research addresses pressing environmental concerns by proposing a robust recycling strategy for the scrap produced during wiring harness manufacturing. By advocating for sustainable practices and responsible waste management, the study highlights the importance of minimizing the ecological footprint of the automotive manufacturing process. In summary, this research provides essential insights and practical solutions for optimizing wiring harness logistics flow in the automotive industry. By implementing these strategies, manufacturers can significantly enhance their production capacity, improve operational efficiency, and maintain competitiveness in an ever-evolving market landscape.

Experimental study on internal damage mechanisms and performance state perception of tunnel linings under different loading paths

The state of tunnel lining structures plays a crucial role in determining safety and service quality throughout their serving life. Therefore, establishing a quantitative method for evaluating the bearing capacity of linings is crucial. Understanding the process and status of crack propagation is key to ensuring structural safety. The three-dimensional development of lining damage cracks is closely related to structural safety. Unveiling the spatial growth of these cracks and the evolution of structural performance is vital for an accurate assessment of lining safety. Key factors in crack propagation, along with non-destructive detection methods, serve as primary approaches for evaluating the safety condition. This paper explores the evolution law and evaluation model of the bearing capacity of plain concrete linings under different loading paths. The distribution of structural stiffness changes significantly under different boundary settings. Therefore, full-scale loading tests of lining components were conducted, designing two types of linings: one intact and the other with initial defects, to simulate the failure of plain concrete linings under diverse loading conditions. The results show that: (1) The damage development of linings exhibits clear staged evolution characteristics; (2) The spatial development of lining cracks can be divided into three stages; (3) There are significant differences in ultrasonic parameters at different stages. Consequently, a method for evaluating the local bearing capacity state of linings based on the coupling of crack characteristics and ultrasonic parameters is proposed; (4) This method is also applicable to linings with initial damage, where damage evolution follows similar stages. The findings provide theoretical guidance for predicting and preventing crack propagation in operational tunnel linings.

Reliability Analysis of High-Pressure Tunnel System Under Multiple Failure Modes Based on Improved Sparrow Search Algorithm–Kriging–Monte Carlo Simulation Method

It is often difficult for a structural safety design method based on deterministic analysis to fully and reasonably reflect the randomness of mechanical parameters, while the traditional reliability analysis method has a large calculation cost and low accuracy. In this paper, based on the seepage–stress coupling numerical model, the random variables affecting the reliability of the collaborative bearing of surrounding rock and lining structures are successfully identified. Then, the improved sparrow search algorithm (ISSA) is used to optimize the hyper-parameters of the Kriging surrogate model, in order to improve the computational efficiency and accuracy of the reliability analysis model. Finally, the ISSA-Kriging-MCS model is used to quantitatively evaluate the reliability of the surrounding rock-reinforced concrete lining structure under multiple failure modes, and the sensitivity of each random variable is discussed in depth. The results show that the high-pressure tunnel structure has high safety and reliability. The reliability indexes of each failure mode decrease with the increase in the coefficient of variation (COV) of random variables. In addition, the same random variable also exhibits varying degrees of influence in different failure modes.

Analysis of the Radial Force of a Piezoelectric Actuator with Interdigitated Spiral Electrodes.

The actuator is a critical component of the micromanipulator. By utilizing the properties of expansion and contraction, the piezoelectric actuator enables the manipulator to handle and grasp miniature objects during micromanipulation. However, in piezoelectric ceramic disc actuators with conventional surface electrode configurations, the actuating force generated in the radial direction is relatively limited. When used as the actuation element of the manipulator, achieving regulation over a wide range of operating strokes becomes challenging. Therefore, altering the electrode structure is necessary to generate a greater radial force, thus enhancing the positioning and grasping capabilities of the operating arm. This paper investigates a piezoelectric actuator with interdigitated spiral electrodes, featuring a constant pitch between adjacent electrodes. The radial force was tested under mechanical clamping conditions, and the influence of the electrical signal was examined. The characteristics of the electrode structure were described, and the working principles of the piezoelectric actuators were analyzed. Theoretical equations were derived for the macroscopic characterization of the radial clamping force of the actuator, based on the piezoelectric constitutive equation, geometric principles, and Bond matrix transformation relationships. A finite element model was developed, reflecting the features of the electrode structure, and finite element simulations were employed to verify the theoretical equations for radial force. To prepare the samples, encircled interdigitated spiral electrode lines were printed on the PZT-52 piezoelectric ceramic disc using a screen printing method. The clamping force experimental platform was established, and experiments on the clamping radial force were conducted with electrical signals of varying waveforms, frequencies, and voltages. The experimental results show that the piezoelectric ceramic disc actuator with an interdigitated spiral electrode line structure, when excited by a stable sine wave operating at 200 V and 0.2 Hz, generated a peak force of 0.37 N. It was 1.76 times greater than that produced by a previously utilized piezoelectric disc with conventional electrode structures.

A review of research on optical true time delay technology

Light controlled phased array has the advantages of fast response speed, compact system, diverse functions, and flexible control, and has been widely applied in many scientific and technological fields. Optical true delay technology (OTTD) is the most direct technical means to achieve phase delay of optical carrier signals, and it is also the most basic technical means to implement optical controlled beamforming systems. In order to fully understand the optical true delay technology, this article first elaborates on the principle of phased array antennas and the reasons for beam strabismus, and analyzes the impact of true delay on the performance of phased array radar. Then, the basic principle, technological progress, and related applications of optical true delay are introduced. Taking four common structures of optical true delay lines as examples,which are micro-ring resonant cavity array, grating ture time delay line, multi-path switchable optical ture time delay line（OTTDL）, and wavelength selective optical delay line, their performance in delay accuracy, adjustable delay range, and frequency bandwidth are compared. Finally, the current problems and future development trends of optical controlled beamforming technology were summarized.

Design and characterization of a circular ring monopole antenna and its MIMO configuration for sub-6 GHz, sub-7 GHz and mm-wave 5G applications

Abstract In this paper, a circular ring monopole antenna, along with its MIMO configuration for sub-6 GHz, sub-7 GHz and mm-wave 5G applications is presented. The single element spans a wide range of frequencies in the sub-6 GHz and mm-wave regions, including a triple-band covering 1.9–6 GHz, 23.3–33.5 GHz, and a super-wide band starting from 37.5 GHz. A two-element MIMO antenna, derived from the single element, has been developed to operate in both frequency regions. It meets the -10 dB criterion with a bandwidth of 4.8 GHz (3.2 to 7.3 GHz) in the sub-6 GHz/sub-7 GHz spectrum. Additionally, the antenna exhibits a super-wide band in the mm-wave region starting at 30.4 GHz. The design covers key bands such as n78, LTE band 46, n96, 39 GHz band, 41 GHz band and more, assigned for 5G sub-6 GHz, sub-7 GHz and mm-wave applications. Improved isolation from 12 dB to 18.5 dB is achieved through a simple decoupling line structure between elements. The proposed MIMO antenna (75 × 56.4 × 1.52 mm³) exhibits a peak gain of 9.8 dBi, high isolation (18.5 dB), low envelope correlation coefficient (ECC <0.016 ), high diversity gain (DG > 9.995), and efficiency (< 97%).

Evolution of 3D Chromatin Folding.

Studies examining the evolution of genomes have focused mainly on sequence conservation. However, the inner working of a cell implies tightly regulated crosstalk between complex gene networks controlled by small dispersed regulatory elements of physically contacting DNA regions. How these different levels of chromatin organization crosstalk in different species underpins the potential for genome evolutionary plasticity. We review the evolution of chromatin organization across the Animal Tree of Life. We introduce general aspects of the mode and tempo of genome evolution to later explore the multiple layers of genome organization. We argue that both genome and chromosome size modulate patterns of chromatin folding and that chromatin interactions facilitate the formation of lineage-specific chromosomal reorganizations, especially in germ cells. Overall, analyzing the mechanistic forces involved in the maintenance of chromatin structure and function of the germ line is critical for understanding genome evolution, maintenance, and inheritance.

Response and seismic resilience of metro tunnels under normal fault dislocation evaluated based on the quantitative method of concrete damage state

The damage to tunnels crossing active fault zones caused by earthquakes can be of a severe and irreversible nature. The paper defines the quantification of the concrete damage state based on the uniaxial compression equation and the tensile-compression curve equation. Furthermore, the paper refines the concrete damage level in conjunction with the damage factor and crack width formulas, which is one of the most significant factors affecting the durability of concrete. A three-dimensional refinement model, constructed using ABAQUS software, was employed to analyse the mechanical response and seismic resilience of the tunnel structure under normal fault displacement with variable section mitigation measures. The model incorporated a number of key parameters, including fortification length, joint location and thickness. The following conclusions were obtained: the tunnel structure is susceptible to tensile damage and the damage is widely distributed under normal fault d; the use of variable section measures can help improve and reduce the overall damage of the cross-fault metro tunnel structure; the use of tensile damage state classification to assess the damage of the tunnel structure can determine the location and extent of the damage; an appropriate protection length is required, too long/short does not maximise the mitigation effect of setting variable section measures; an appropriate lining length is required; and the lining structure is not suitable for the tunnel structure. An appropriate location and thickness of the lining structure will help to reduce the overall damage to the structure. The application of localised reinforcement to the structure, in conjunction with variable section, serves to minimise the probability of collapse of the tunnel as a whole and to enhance the seismic resilience of the underground structure across the active fault zone.

R391 human dominant mutation does not affect TubB4b localization and sensory hair cells structure in zebrafish inner ear and lateral line

Heterozygous R391 TUBB4B pathogenic variations are responsible for an association of hearing loss and retinal dystrophy in human. With the goal of understanding the functions of TuBB4b and the pathogenic role of R391 variations, we characterized tubB4B in zebrafish and identified the gene regulatory elements necessary and sufficient for expression of TubB4b as in endogenous tissues. Using knock-out and transgenic approaches, we determined that R391 mutations impair neither localization of TubB4B within sensory hair cells (SHC) nor their structure, but induced to a small decrease in SHC number from anterior crista. Expression of R391 mutations in sensory hair cells has no effect on zebrafish audition, suggesting a different equilibrium between various tubulin isotypes in zebrafish possibly due to compensatory mechanisms. The careful expression analysis and transgenic tools generated in this study could help understand how recently described pathogenic variants lead to more severe clinical forms of TUBB4B-related diseases.

Metallic Ca Aggregates Formed Along Ion Tracks and Optical Anisotropy in CaF2 Crystals Irradiated with Swift Heavy Ions

It is known that swift heavy ion (SHI) irradiation induces the shape elongation of metal nanoparticles (NPs) embedded in transparent insulators, which results in anisotropic optical absorption. Here, we report another type of the optical anisotropy induced in CaF2 crystals without including intentionally embedded metal NPs. The CaF2 samples were irradiated with 200 MeV Xe14+ ions with an incident angle of 45° from the surface normal. With the increasing fluence, an absorption band at ~550 nm, which is ascribed to Ca aggregates, increases both the intensity and the anisotropy. XTEM observation clarified the formation of the continuous line structures and the discontinuous NP chains parallel to the SHI beam. Numerical simulations of the optical absorption spectra suggested the NP chains but not the continuous line structures as the origin of the anisotropy. The optical anisotropy in CaF2 irradiated with SHIs is different from the shape elongation of NPs.