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Structural-response reconstruction is of great importance to enrich monitoring data for better understanding of the structural operation status. In this paper, a data-driven based structural-response reconstruction approach by generating response data via a convolutional process is proposed. A conditional generative adversarial network (cGAN) is employed to establish the spatial relationship between the global and local response in the form of a response nephogram. In this way, the reconstruction process will be independent of the physical modeling of the engineering problem. The validation via experiment of a steel frame in the lab and an in situ bridge test reveals that the reconstructed responses are of high accuracy. Theoretical analysis shows that as the sensor quantity increases, reconstruction accuracy rises and remains when the optimal sensor arrangement is reached.

The timely identification of differential settlement of track foundations is of great significance for the safety of train operation and the maintenance of track structures. However, traditional monitoring techniques cannot meet the requirements of efficient, real-time, and automatic monitoring of track foundation settlement. In order to solve these problems, a real-time identification method based on a gated recurrent unit (GRU) neural network is proposed for the differential settlement of track foundations monitoring. According to parameter sensitivity analysis, the vertical acceleration of the vehicle is selected as the known data fed into the GRU network for differential settlement identification. Then the GRU network is employed to establish the nonlinear relationship between the vertical acceleration of the vehicle and the differential settlement of the track foundation. The results indicate that the longitudinal continuous differential settlement distribution curve of track foundations could be accurately identified with GRU neural network through the real-time vibration response of the vehicle–track. The current method may provide a new means for the real-time and efficient identification of the differential settlement of track foundations.

In order to further promote the application of segment-assembled bridge piers in medium- and high-intensity areas, and to reduce the post-earthquake damage and repair cost of bridge piers, in this paper, a precast segmental concrete-filled steel-tube bridge pier (PSCFSTBP) with an external arched energy dissipation device (AEDD) is proposed. Firstly, the effectiveness of the finite-element analysis software ABAQUS 6.14-4 is proved by the test results of the PSCFSTBP and the corresponding finite-element model analysis results. Secondly, ABAQUS 6.14-4 was used to establish four-segment PSCFSTBP models with four different structural forms (non-energy dissipation device, external arch steel plate, external vertical steel plate, and external AEDD), and the seismic performance of each model was compared and analyzed under reciprocating displacement loading. The results show that compared with the PSCFSTBP with an external AEDD, the lateral bearing capacity of the PSCFSTBP with an external vertical steel plate is increased by about 11.9%, and the initial stiffness is increased by about 2.5%. Compared with the PSCFSTBP with an external arch steel plate, the lateral bearing capacity, initial stiffness, and energy dissipation capacity are increased by 28.8%, 4.6%, and 13 times, respectively. Compared with the PSCFSTBP without an energy dissipation device, its lateral bearing capacity, initial stiffness, and energy dissipation capacity are increased by 39.4%, 10.4%, and 18 times, respectively. The residual displacement of the PSCFSTBP with an external AEDD is kept within 1 mm in the whole displacement loading stage, the offset rate is less than 1%, and the pier damage is controllable, which can realize rapid repair after an earthquake. Finally, the multi-level energy consumption and local replacement of the AEDD are also explored.

In order to improve the construction efficiency of piers and reduce the local damage of piers, concrete-filled steel tubes (CFST) are used to precast pier segments. Aiming at the problems of the poor integrity and insufficient energy dissipation capacity of dry joint segmental assembled piers, segmental assembled concrete-filled steel tubular piers with external replaceable energy dissipators are being developed. Based on the low cyclic test of a segmental assembled CFST pier, the finite element numerical simulation model of a CFST pier is established based on ABAQUS software, and the validity of the numerical model is verified by the experimental results. The effects of the section ratio, axial compression ratio, and initial prestress on the seismic performance of piers are studied through a pseudostatic analysis. The results show that an increase in the section ratio can improve the lateral bearing capacity and energy dissipation capacity of the pier. When the section ratio is increased to 4%, the energy dissipation capacity of a CFST pier is increased by 77.8% and the lateral bearing capacity is increased by 33.9% compared with a section ratio of 2%, but the residual displacement of the pier top also increases. With an increase in the axial compression ratio, the energy dissipation capacity of the pier is significantly improved; when the axial compression ratio is increased to 0.30, the energy dissipation capacity of CFST piers is increased by 27.5% compared with a section ratio of 0.05, the residual displacement of the pier top is reduced, and the self-resetting effect of the pier is improved. A change in the initial prestress has no effect on the energy dissipation capacity of piers. Finally, based on an analysis of mechanical theory, a formula of bending capacity suitable for this type of pier is proposed, and the error is within 10%.

Water leakage and debris accumulation caused by the expansion joints in a bridge superstructure reduce the service life of the bridge and increase the maintenance costs. A link slab is an effective means to eliminate the expansion joints, providing a continuous deck system. However, the load-caused concrete cracking of the link slab also leads to problems associated with water leakage and rebar corrosion. In order to solve these problems, a new type of steel–concrete composite link slab (SCC-LS) was designed to continuously subject the bridge deck to a positive bending moment and surface concrete compression, which reduced the cracking damage in the link slab. This paper presents the mechanical performance results of the SCC-LS obtained using full-scale model tests. Furthermore, theoretical calculations and finite element (FE) models of the jointless bridge validated the performance based on the experimental results. The results of this study show that the SCC-LS can effectively solve the problem of concrete cracking on the surface of the bridge deck, which has theoretical reference significance and engineering application value for the structural design, maintenance and transformation of continuous simply supported bridge decks and the promotion of seamless bridges.

Under the trend of the rapid development of the internet of things (IoT), sensing for dynamic behaviors is widely needed in many fields such as traffic management, industrial production, medical treatment, building health monitoring, etc. Due to the feature of power supply independence and excellent working performance under a low-frequency environment, triboelectric nanogenerators (TENGs) as sensors are attracting more and more attention. In this paper, a comprehensive review focusing on the recent advance of TENGs as sensors for dynamic behaviors is conducted. The structure and material are two major factors affecting the performance of sensors. Different structure designs are proposed to make the sensor suitable for different sensing occasions and improve the working performance of the sensors. As for materials, new materials with stronger abilities to gain or lose electrons are fabricated to obtain higher surface charge density. Improving the surface roughness of material by surface engineering techniques is another strategy to improve the output performance of TENG. Based on the advancement of TENG structures and materials, plenty of applications of TENG-based sensors have been developed such as city traffic management, human–computer interaction, health monitoring of infrastructure, etc. It is believed that TENG-based sensors will be gradually commercialized and become the mainstream sensors for dynamic sensing.

The metro tunnel lines built in a soft soil area may suffer from tunnel differential settlement due to the high compressibility of soft soil, the engineering constructions nearby tunnel lines, and the cyclic load of metro trains. In this paper, a dynamic coupling model for a metro train-monolithic bed track system under tunnel differential settlement is established. A cosine function is introduced to simulate a real settlement curve measured from a metro tunnel in southern China, and the vibration performance of the train-track system under tunnel settlements is investigated in both the time domain and frequency domain. Based on the standards for the train safety and passengers’ comfort, the speed limit for the metro train traveling on a monolithic bed track with different settlement distributions are concluded. The present research could be useful for the operation and maintenance of metro tunnels in soft soil areas.

Weathered granite has been widely used as an emerging foundation filler for constructing transportation infrastructure. However, various softened rocks weathered due to exposure to water have special properties. Thus, it is necessary to gain a thorough understanding of the various physical and mechanical properties of weathered granite after exposure to water in order to avoid engineering accidents. To this end, this paper conducted a series of undrained triaxial shear tests to compare the mechanical behavior of weathered granite in natural and saturated states. The results demonstrate that the strength of the weathered granite significantly declines when it is exposed to water, and it exhibits noticeable water softening characteristics. Consolidation methods also affect the mechanical properties of weathered granite. The degree of softening of weathered granite decreases with an increase in the deviator stress imposed by the deviator stress consolidation. Subsequently, we established an empirical model for the strain softening of weathered granite suitable for natural and saturated conditions. This model took the elastic modulus of weathered granite before the peak strength as a measure and introduced the strength parameters of the internal friction angle (φ) and the internal cohesion (c). First, the fitted function correlating c and φ with the plastic internal variable was determined, and then the relationship between the strength and the strain-softening parameters was established so as to obtain the complete stress–strain curve of the granite rock. Finally, validation studies were performed to address the capability of the model to predict permanent deformation. It provides a theoretical basis for predicting and calculating the strain softening of weathered granite exposed to water.

The pressure-holding sampling technology for deep-sea sediments has been identified as a prerequisite for studying the sedimentary environment with respect to the mechanical and biological characteristics of sediments. Thus, in this study, we designed a set of abyssal sediment sampling systems based on image recognition technology. First, a system camera was used to obtain the movement trajectory of the sampling cone in the laboratory simulation scene. After collecting the data of the image including the sampler, we preprocessed the data using an underwater image restoration method based on the dark channel prior. An image recognition unit was used to verify that the position of the sampling cone meets the requirement. The main control unit controlled the actuator of the sampling device to accurately control the position of the sampling cone. Furthermore, we used the Mask R-convolutional neural network architecture to build the network framework for controlling the expansion and braking of the sampler. The experimental results showed that the system achieved a very high detection accuracy for the position of the sampling cone. [ABSTRACT FROM AUTHOR]

Research has been conducted on martinellic acid. Results demonstrate that this compound can be synthesized via guanylation reaction of guanylation reagent with tricyclic triamine.

Constitutive overexpression and activation of NPM-ALK fusion protein [t(2:5)(p23;q35)] is a key oncogenic event that drives the survival and proliferation of anaplastic large-cell lymphomas (ALCLs). We have identified a highly potent and selective small-molecule ALK inhibitor, NVP-TAE684, which blocked the growth of ALCL-derived and ALK-dependent cell lines with IC50 values between 2 and 10 nM. NVP-TAE684 treatment resulted in a rapid and sustained inhibition of phosphorylation of NPM-ALK and its down-stream effectors and subsequent induction of apoptosis and cell cycle arrest. In vivo, NVP-TAE684 suppressed lymphomagenesis in two independent models of ALK-positive ALCL and induced regression of established Karpas-299 lymphomas. NVP-TAE684 also induced clown-regulation of CD30 expression, suggesting that CD30 may be used as a biomarker of therapeutic NPM-ALK kinase activity inhibition. [ABSTRACT FROM AUTHOR]

Focuses on expansion of pyrimidine diphosphosugar libraries by structure-based nucleotidylyltransferase engineering. Approach for generating diverse libraries of glycosylated biomolecules; Increase in the set of α-D-hexopyranosyl phosphates by a single amino acid substitution in the substrate-binding pocket.

In nature, the attachment of sugars to small molecules is often used to mediate targeting, mechanism of action and/or pharmacology. As an alternative to pathway engineering or total synthesis, we report a useful method, in vitro glycorandomization (IVG), to diversify the glycosylation patterns of complex natural products. We have used flexible glycosyltransferases on nucleotide diphosphosugar (NDP-sugar) libraries to generate glycorandomized natural products and then applied chemoselective ligation to produce monoglycosylated vancomycins that rival vancomycin. [ABSTRACT FROM AUTHOR]