A new seismic resilient steel moment connection with top shear tabs and bottom replaceable metallic fuse is proposed. The shear tabs are realized by a combination of shear angles, with or without ...shear plates or splice plates, while a buckling-restrained plate (BRP) is employed as the fuse. Both the shear tabs and BRP are placed at a splice location which represents the beam inflection point under gravity load. Analytical models were developed to determine the stiffness, strength, and deformation of the proposed connection, as well as a trilinear moment-rotation relationship at the spliced section. In this way, a coordinated seismic design procedure to achieve structural serviceability and resilience in steel moment frames with the proposed connection was derived based on the equal-stiffness and zero-moment strategies. Cyclic loading tests of full-scale beam-to-column subassemblies equipped with the proposed connection were conducted. Three resilient connections with different shear tabs (bolted/welded shear angles above/below the beam top flanges) were examined and compared with a conventional fully welded connection. The test results validated the concept and confirmed success of the analytical and design methods to ensure sufficient lateral stiffness and concentrate plastic damage into the BRP. Moreover, the resilient connections with bolted or welded shear angles above the beam top flanges exhibited about 11–18% higher moment resistance at 4% drift and 20% more energy dissipation, and thus are recommended over that with welded shear angles beneath the beam top flanges.
•A new seismic resilient connection with top shear tabs and bottom fuse is proposed.•The shear tabs comprise a pair of angles with or without shear or splice plates.•A buckling-restrained plate is employed as the replaceable metallic fuse.•A coordinated seismic design procedure was derived for this connection.•Analytical and experimental study was conducted to validate the concept and design.
Microbial infection can cause problems for public health, and to realize efficient microorganism detection is of great importance. However, the simultaneous identification of microorganism still ...faces challenges due to the high similarity of the surface microenvironment. With the assistance of machine learning algorithms, nanomaterials-based optical sensor arrays are emerging as a promising analysis technique for microorganism discrimination with the merits of high sensitivity, time-saving and easy operation. We present here the recent development of machine learning assisted optical sensor arrays for microorganism identification. In the first part, five types of optical nano-sensor arrays that include fluorescent sensor arrays, colorimetric sensor arrays, multi-response-based sensor arrays, SERS-based sensor arrays and FTIR-based sensor arrays are discussed. Then, eight commonly used machine learning algorithms in the array-based sensors are introduced. Detailed calculation principles involved in the statistical analysis of array-based sensors are overviewed. It is ended by outlining the current challenges and perspectives.
•Machine learning assisted optical sensor arrays for microorganism identification are surveyed.•Five types of optical sensor arrays on recently developed nanomaterials are discussed.•Eight machine learning algorithms in the array-based sensors are reviewed.•It provides guidance for researchers in pharmaceutical R&D.
Based on the yield mechanism control principle of “strong columns and weak beams, strong joints and weak components” in steel frames connected by top-and-seat steel angles, this paper proposes a ...method to define the relationship between the bending capacity of various components through inequality iteration and deduction. A number of component parameters has been identified that enables control of the yielding sequence in structural components. The study also developed an objective function and used genetic algorithms to create a multi-objective optimization technique for semi-rigid steel frame structures. The method considers the non-dominated cost interval, resulting in a more comprehensive approach. From the optimization case studies against the published experimental results and finite element simulations, it demonstrates that the proposed approach efficiently manages the yielding sequence and minimizes the decision space. The optimization model provides the coordination optimization between structural cost and lateral base shear capacity.
•A new method to calculate relationship between semi-rigid joint parameters and structural components' yield sequences.•A new multi-objective optimization method for steel frame structure.•A new method to improve the optimization efficiency
A new seismic resilient steel beam-to-column joint using replaceable buckling-restrained plates for energy dissipation was proposed in this paper. Such a joint consists of a column tree and an ...interior beam segment connected on site through bolted steel plates located inside beam flanges. The steel plates are considered as structural fuses to attract inelastic damage and dissipate energy. Their potential buckling is restrained by intentionally designed C-shaped shear tabs, which are also used to connect the beam webs to transfer the beam shear. Thus, both stable strength and superior energy dissipation capacity can be guaranteed. Six cyclic tests were conducted to study the seismic behavior and post-earthquake repair performance. The results evidenced that this joint was able to develop a normalized cumulative plastic rotation of 550 to 1100 until failure. Fuse plates could be quickly replaced after testing and the repaired joint developed nearly identical seismic performance as the original one. The proposed new joint provides an alternative solution, which is both economical and effective, for seismic resilient steel structures.
•Plastic damage could be effectively concentrated in the replaceable fuse plates.•The repaired joint possessed similar seismic performance with the virgin one.•Maximum story drift ratio that could be developed was believed to be at least 7%.•FP-type fuse plate and stiffened shear tab were suggested in engineering practice.•This joint had superior performance on low-cycle fatigue.
The low spatial and temporal resolution and poor accuracy of real-time zenith tropospheric delay (ZTD) have always been one of the main constraints during the development of real-time GNSS ...applications. This paper presents a method to obtain real-time ZTD grid data in Chinese regions utilizing the ZTD-modified ERA5 grid products from GNSS stations. Initially, the original ZTD fitting function for vertical variation is improved. Then, the real-time ZTD grid data for the Chinese region (RZTDG) could be obtained by correcting the 7-day earlier ERA5 data through the real-time ZTD data from the GNSS stations. In this paper, we analyze the performance of the model under various weather conditions, and the results show that it still keeps a high accuracy even under variable weather conditions. ZTD data from 66 radiosonde stations in China in 2022 are used as reference values to evaluate the accuracy of the RZTDG. Experimental results show that the RMSE (2.3 cm) and MAE (1.8 cm) of the RZTDG are comparable to the ERA5 data of the day (RMSE: 2.4 cm, MAE: 1.8 cm) and significantly better than the accuracy of the HGPT2 (RMSE: 5.1 cm, MAE: 4.1 cm). Meanwhile, the Bias of RZTDG (0.1 cm) is much smaller than the Bias of HGPT2 (−0.9 cm) and the Bias of ERA5 (−0.8 cm), proving that the method in this paper has less deviation from the radiosonde ZTD data. Finally, the convergence times of the float PPP with and without tropospheric constraints are counted for 120 GNSS stations for DOY 11–13, DOY 101–103, and DOY 192–194 in 2022. The results show that the convergence time of the float PPP is reduced by 30% after constraining the ZTD using RZTDG.
•Propose a accurate fitting function descibing the ZTD variation with elevations.•The methodology for obtaining real-time ZTD grid data is simple and requires only GNSS station ZTD data and ERA5 data.•Constraining real-time ppp using RZTDG data can drastically reduce the convergence time of ppp..
Nitric oxide as a signal molecule participates in a variety of physiological and pathological processes but its real-time detection in cell assays still faces challenging because of the trace amount, ...short half-life and easy conversion to other substances. We report here a rational design by assembling highly π-conjugated and small capacitive gaphdiyne (GDY) with a coordination complex of hemin (HEM) into a molecularly assembled material of GDY/HEM to achieve ultrafast and real-time monitoring of nitric oxide in cell assays. GDY comprising alkynyl C atoms can hybridize with the HEM to enable strong π-π interaction and atomic dispersion of iron sites while avoiding the formation of catalytically inactive dimer for the HEM. These characteristics make the GDY/HEM an excellent sensing material towards nitric oxide, which has an ultrafast response time of 0.95 s, a low detection limit of 7 nM and long linear range up to 151.38 μΜ. The GDY/HEM realizes real-time monitoring nitric oxide released from cancer and normal cells, demonstrating its capability for cell analysis.
•Graphdiyne is explored for the first time in live-cell nitric oxide detection.•GDY/HEM was fabricated by assembling GDY and a Fe-coordination complex.•GDY enables atomic dispersion of HEM while avoiding catalytically inactive dimer.•It achieves an ultrafast response of 0.95 s and a low detection limit of 7 nM.•It realizes real-time monitoring nitric oxide molecules in live-cell assays.
Dopamine (DA) as an important neurotransmitter plays an important role in physiological activities, and its abnormal level can cause diseases such as Parkinson's disease. However, the clinical ...analysis of DA mainly relies on time-consuming and expensive liquid chromatography and molecular spectrometer. We present here a design and fabrication of inexpensive strip sensor constructed from screen printed electrodes for sensitive and selective detection of DA. The ink used for printing the strips contains Shewanella putrefaciens-templated porous N-doped carbon nanorods (N-doped CN) and Au nanoparticles (Au NPs), in which the N-doping enhances CN's negative charge to electrostatically attract the positively charged DA with strong adsorption for achieving fast electron transfer. Moreover, results indicate that the Au NPs impregnation in N-doped CN renders much more catalytic reaction sites toward DA oxidation current. The strip sensor exhibits high sensitivity for DA detection with a broad linear range of 0.02–700 μM and a low detection limit of 0.007 μM as well as good selectivity and superior flexibility for great potential in wearable applications. The strip sensor further performs an accurate detection of DA in human serum, providing a powerful analytical tool for diagnosis of DA related diseases in clinical analysis.
•Screen-printed analytical strip for sensitive detection of DA.•Au NPs/N-doped CN synergistically offers high catalytic sites for DA oxidation.•The sensor has larger linear range and lower LOD than reported screen-printed ones.•The sensor shows great flexibility and accuracy of DA detection in human serum.
The detailed finite element model (FEM) of a new replaceable fuse steel beam-to-column joint proposed previously, where bolted steel plates located between the beam and C-shaped shear tab flanges in ...the beam splicing region behave as structural fuses to dissipate energy with their buckling controlled by the surrounding flanges, was developed in this paper and subjected to cyclic loading at the beam end. The simulated results matched the test results well in terms of the hysteresis curves (and the corresponding backbone curves) and failure modes. Based on the validated FEM, subsequent parametric studies were carried out to investigate the influences of the fuse plate type and slenderness ratio, and the slip coefficient between the steel plates, on seismic performance of this joint. The parametric analysis indicated that, the joint could accommodate an ultimate story drift angle of 6% without damaging the beam or shear tab flanges by using flat-type (FP) fuse plates, which are recommended over slotted-type (SP) and double-slotted-type (DSP) fuse plates, as the latter both types developed earlier buckling than the former FP-type. Eccentric-type (EP) fuse plates are also suggested, with which the joint equipped sustained an ultimate story drift angle of at least 8%. In addition, the slenderness ratio of FP-type fuse plates is recommended to be controlled within 44 since the fuse plates with higher slenderness ratios introduced damage through buckling to the shear tab flanges at an earlier stage, while the slip coefficient presented no significant impact on the joint seismic performance.
•Numerical simulation matched the experimental hysteresis curves and failure modes.•The joint with flat-type fuses exhibited an ultimate story drift angle of 6%.•The joint with eccentric-type fuses sustained a story drift angle of at least 8%.•The flat-type fuses are preferred over slotted-type and double-slotted-type fuses.•The flat-type fuse slenderness ratio is suggested to be controlled within 44.
By rationally introducing Ce(III) and Tb(III) into a coordination polymer (CP), a series of lanthanide bimetallic coordination polymers (Tb:Ce-BCPs) has been prepared in this work. Compared with pure ...Tb-CP and Ce-CP, bimetallic Tb:Ce-BCPs show stronger and more stable ECL intensity, which is mainly attributed to the “dual sensitization effect” combined with the energy transfer from Ce(III) to Tb(III) and the antenna effect from the ligand to the center atoms of Ce(III) and Tb(III). In the meantime, after explore the ECL intensity and morphologies of all these Tb:Ce-BCPs, the results show that the morphologies and ECL intensities of Tb:Ce-BCPs can be adjusted by doping different molar ratios of Ce(III) in Tb:Ce-BCP. Excitingly, Ce(III) can also act as a co-reaction accelerator, effectively promoting S2O82− to generate more SO4•−, thereby enhancing the ECL intensity of Tb:Ce-BCP. That is to say, Ce(III) plays a triple role in Tb:Ce-BCP. Furthermore, the ECL strength of Tb:Ce-BCP decreased by only 1.8% and 3.5%, respectively after the modified electrode was scanned for 800 s and stored for one month. Enlightened by the excellent ECL properties of Tb:Ce-BCP, we modified Tb:Ce-BCP directly on the surface of electrode, and explored its application in electroanalytical chemistry through the detection of epinephrine (EP) and the detection limit is 33 fmol L−1. Significantly, our ECL sensing strategy promotes the application of lanthanides in ECL sensor and opens vast possibilities for the synthesis of a new generation of ECL emitter in electroanalytical fields.
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•A series of Tb:Ce-BCP has been synthesized by rationally introducing Ce(III) and Tb(III).•Doping with Ce(III) can not only adjust morphology of Tb:Ce-BCP, but also improve its ECL intensity.•Tb:Ce-BCP shows improved ECL intensity due to the “dual sensitization effect”.•The “dual sensitization effect” composed of the antenna effect and energy transfer.•This strategy has successfully achieved high-sensitivity detection of epinephrine.
