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• Experiments were conducted to strengthen the Ti60 materials using ball burnishing and shot peening. • The evolution of surface characteristics during room and elevated temperature fatigue was studied in detail. • An in-depth analysis was conducted on the fatigue failure mechanisms of the two strengthening processes. To clarify the evolution of surface characteristics of Ti60 alloy induced by ball burnishing and shot peening and their anti-fatigue mechanism during tensile-compression fatigue, room temperature and 450℃ elevated temperature fatigue tests were conducted on burnished and shot peened round bar Ti60 samples. Residual stresses, microhardness, and microstructures were analyzed during fatigue, and the fracture mechanism was investigated through fractography. The results show that the residual stress relaxation rate of the burnished sample is lower than that of the shot peened sample. After fatigue, the strengthened samples showed reduced microhardness and fewer low angle grain boundaries. The strengthened samples are both subsurface initiation, and the depth of initiation of the burnished sample is greater than that of the shot peened sample. The fatigue initiation mode at room temperature and 450℃ high temperature is quasi cleavage. No fatigue striations are observed at room temperature fatigue propagation zone, but they can be observed at 450℃ elevated temperature. The dimples can be observed at room temperature fatigue transient fracture zone. However, at 450℃ elevated temperature fatigue transient fracture zone, the dimples and quasi-cleavage can be observed simultaneously, indicating a mixed fracture mode. In addition, the crack shape of the strengthened sample is a wide top and narrow bottom shape due to the compressive residual stress layer. [ABSTRACT FROM AUTHOR]

This paper presents an experimental study on seismic behavior of ultra-high performance steel fiber reinforced concrete (UHPSFRC) columns. Based on a series of cyclic loading tests on 14 UHPSFRC specimens subjected to combined static axial loading and cyclic lateral loading, the investigation and analysis have been carried out on crack status, failure modes, hysteretic loops, skeleton curves, strength and stiffness degradation, energy dissipation capacity and ductility of UHPSFRC columns. The influence of stirrup spacing, type of stirrup, axial compression ratio and shear span ratio on the seismic performance of UHPSFRC columns was also investigated in details. The experiment results show that three typical failure modes are observed, i.e., flexural, flexural-shear and shear failure mode. The existence of steel fiber could prevent the cracked concrete from spalling efficiently and delay the bulking of longitudinal reinforcement further. It noteworthy that the limit plastic drift ratio of all columns changes from 0.036 to 0.061, indicating that the UHPSFRC columns represent a good ductility which is obviously different from the conventional high strength concrete columns that exhibit much more brittleness with the increase of strength. [ABSTRACT FROM AUTHOR]

Mycoplasma synoviae (MS) is an important avian pathogen that has brought substantial economic losses to the global poultry industry. Fast and accurate diagnosis is one of the critical factors for the control of MS infection. This study established a simple, rapid and visual detection method for MS using a recombinase-aided amplification (RAA) combined with a lateral flow dipstick (LFD). The reaction temperature and time of the RAA-LFD assay were optimized after selecting the primers and probe, and the specificity and sensitivity rates were analyzed. The results showed that RAA could amplify the target gene in 20 min at a constant temperature of 38°C, and the amplification products could be visualized by LFD within 5 min. There was no cross-reaction with Mycoplasma gallisepticum (MG), Pasteurella multocida ( P. multocida ), Escherichia coli ( E. coli ), Newcastle disease virus (NDV), infectious bursal disease virus (IBDV), infectious bronchitis virus (IBV), and avian reovirus (ARV). Furthermore, the RAA-LFD assay exhibited high sensitivity with a detection limit of 10 copies/μL. A total of 128 clinical samples with suspected infection of MS were tested by RAA-LFD, PCR, and real-time fluorescence quantitative PCR (RFQ-PCR). The coincidence rate of the detection results was 95.3% between RAA-LFD and PCR, and 98.4% between RAA-LFD and RFQ-PCR. These results suggested that the RAA-LFD method established in the present study was easy to use and was associated with strong specificity and high sensitivity. This method was very suitable for the rapid detection of MS in clinical practice. [ABSTRACT FROM AUTHOR]