Laccases have been used for the decolorization and detoxification of synthetic dyes due to their ability to oxidize a wide variety of dyes with water as the sole byproduct. A putative laccase gene (LacTT) from Thermus thermophilus SG0.5JP17-16 was screened using the genome mining approach, and it was highly expressed in Pichia pastoris, yielding a high laccase activity of 6130 U/L in a 10-L fermentor. The LacTT open reading frame encoded a protein of 466 amino acid residues with four putative Cu-binding regions. The optimal pH of the recombinant LacTT was 4.5, 6.0, 7.5 and 8.0 with 2,2'-azino-bis(3-ethylbenzothazoline-6-sulfonic acid) (ABTS), syringaldazine (SGZ), guaiacol, and 2,6-dimethoxyphenol (2,6-DMP) as the substrate, respectively. The optimal temperature of LacTT was 90°C with guaiacol as the substrate. LacTT was highly stable at pH 4.0–11.0 and thermostable at 40°C–90°C, confirming that it is a pH-stable and thermostable laccase. Furthermore, LacTT also exhibited high tolerance to halides such as NaCl, NaBr and NaF, and decolorized 100%, 94%, 94% and 73% of Congo Red, Reactive Black B and Reactive Black WNN, and Remazol Brilliant Blue R, respectively. Interestingly, addition of high concentration of NaCl increased the RBBR decolorization efficiency of LacTT. These results suggest that LacTT is a good candidate for industrial applications such as dyestuff processing and degradation of dyes in textile wastewaters.

This paper proposes a tension-compression damage model for concrete materials, formulated within the framework of thermodynamics of irreversible processes. The aim of this work is to solve the following problems: the premature divergence of numerical solutions under general loading conditions due to the conflict of tensile and compressive damage bounding surfaces, which is a result of the application of the spectral decomposition method to distinguish tension and compression, and the unsatisfactory reproduction of distinct tension-compression behaviors of concrete by strain-driven damage models. The former is solved by the sign of the volumetric deformation, while the latter is solved via two separated dissipation mechanisms. Moreover, of specific interest is an improved solution to the problem of mesh-size dependency using consistent crack bandwidths, which takes into account situations with irregular meshes and arbitrary crack directions in the context of the crack band approach. The performance of the model is validated by the well-documented experimental data. The simplicity and the explicit integration of the constitutive equations render the model well suitable for large-scale computations.

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In practice, the internal rubber dampers are widely installed inside the cable guide pipe between the external viscous damper and the cable anchorage. In order to study the effect of the internal damper on the performance of the external viscous damper, the theoretical analysis model of a taut cable with an internal rubber damper and an external viscous damper is established in this paper, where the internal damper is assumed to be a high damping rubber damper with a flexible support and the external damper is considered to be a linear viscous damper. Then, the numerical iterative formula and approximate solution expression for the cable modal damping ratio are derived. Based on the approximate solution, the parameters of the internal rubber damper are analyzed comprehensively, and its influence on the cable modal damping in cable multimode is studied as well. Results show that, except for the support flexibility of the internal rubber damper, other parameters will have a negative effect on external viscous damper effectiveness. From the perspective of cable multimode vibration control, the installation of an internal rubber damper significantly weakens the modal damping, and this effect is more pronounced in lower frequency modes.

This paper presents an analytical study on the stress concentration problem due to a cuboid hole in structures. Base on the theory of elasticity and the finite element method, the governing equation with cyclic periodicities in three directions is established. By using the U-transformation technique, the nodal displacement solutions are given out in analytical form. Once the nodal displacements of the cuboid hole are derived, it is easy to discus the stress distribution around the hole. As an example, the paper discusses the problem that a cube hole in structure which is under x-direction tension loading, and obtains the stress concentration factor is 1.90. The research process can be extended to study the stress concentration problems under other loading conditions

The friction and anti‐wear behaviours of hexagonal boron nitride (h‐BN) nanoparticles as a lithium lubricating grease additive are being investigated under sliding conditions. The grease with 3 wt% 60 nm h‐BN particles and the grease with 1 wt% 500 nm h‐BN particles lead to 22.34% and 20.18% reductions in the wear scar diameter, respectively, although the friction coefficients slightly decrease. The boric acid H3BO3 with layer‐crystal structure produces during the friction process, and the synergistic effect of h‐BN nanoparticles and H3BO3 makes friction reduction and wear‐resistant enhancement. Furthermore, the 60 nm h‐BN particles filled in the asperity valleys of the friction surface make a rolling effect and establish a protective film, while the 500 nm h‐BN particles shield the asperity contact between friction pairs and make a polishing effect as well.

High-damping rubber (HDR) dampers have the advantages of convenience for various shapes of pressure blocks, aesthetic installation, easy maintenance, temperature stability, etc.; thus, they present good application prospects in the vibration reduction of stay cables. Hence, a model of a taut cable equipped with two types of HDR damper—i.e., HDR damper and tuned mass–high-damping rubber damper (TM-HDR-D)—is established herein. Then, based on this theoretical model, the effect of each damper acting alone and in combination on the cable’s additional modal damping is studied. Finally, an actual cable of a cable-stayed bridge is used to study the effectiveness of two dampers for practical engineering. The results show that, when the TM-HDR-D has a small mass, the total additional modal damping of the cable approximates the superposition of the respective effects of the two dampers. The damping effect of HDR mainly depends on its stiffness and installation position; meanwhile, the damping contribution of TM-HDR-D is mainly related to its tuning frequency and installation position. In practical engineering, the smaller installation mass of TM-HDR-D can make up for the lack of damping enhancement of the cable-end HDR damper.

Open die hot forging has a wide industrial application on deforming ingot into billet with desired dimension and qualified internal microstructure. An example open die forging process of Ti-6Al-4V ingot is selected herein. A 3D FE-based numerical method was used to investigate the open die forging process with respect to the real working conditions. The simulation results were validated by the collected experimental process parameters from the forging system. Moreover, design of experiment method is adopted regarding the variation of process parameters to reveal the effects of critical factors on product deformation and quality characteristics. Results show that the process parameters including press speed, feed and reduction has significant effect on the workpiece deformation and effective strain which represents the forged billet formability and quality. Improved process parameters method is suggested with respect to the experienced benchmark based on the sensitivity analysis. Keywords: Open die forging; Ti-6Al-4V alloy; Sensitivity analysis; Process parameter; Numerical simulation;