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Pectobacterium carotovorum (Pc) causing potato tuber soft rot uses N-acyl-L-homoserine lactones (AHLs) to control the production of virulence factors via quorum sensing (QS). Some bacteria produce enzymes to inactivate the AHL signals of pathogenic bacteria via a phenomenon known as quorum quenching. One hundred bacterial isolates from potato tubers were screened for AHL-degrading activity using biosensor strain Chromobacterium violaceum CV026. Of these isolates, 20 were able to inactivate AHLs from the pathogenic bacteria in vitro. Of the 20 isolates, 6 attenuated tissue maceration of potato tubers by Pc. Suppression of tuber soft rot was observed even when these isolates were applied 24 h after the pathogen was introduced. Their colonization in tubers was approximately 10 3 -10 4 cfu/g tuber, 7 days after inoculation. These isolates were identified as Bacillus sp., Variovorax sp., Variovorax paradoxus and Agrobacterium tumefaciens. Four of these isolates showed putative AHL-lactonase activity and provided the most significant protection against Pc. Therefore, AHL-degrading endophytic bacteria can be utilized as a novel biocontrol agent of potato tuber soft rot in Vietnam.

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Nonlinear buckling analysis for honeycomb auxetic-core sandwich toroidal shell segments with CNT-reinforced face sheets surrounded by elastic foundations under the radial pressure is presented in this study. The basic equation system of shells is established based on the von Kármán–Donnell nonlinear shell theory, combined with Stein and McElman approximation. Meanwhile, the foundation-shell elastic interaction is simulated by the foundation model based on the Pasternak assumption. The Galerkin procedure is utilized to achieve the pre-buckling and post-buckling responses for the shell, from which the radially critical buckling load is determined. Numerical analysis shows the various influences of auxetic-core layer, CNT-reinforced face sheets, and elastic foundation on the pre-buckling and postbuckling behavior of sandwich shells with CNT reinforced face sheets.

Auxetic materials are usually designed as cores for structures subject to high impulse loads. Furthermore, the lightweight and high load capacity of the auxetic core construction is also an important advantage even for structures subjected to static loads. The combination of auxetic core and face sheets made by the advanced composite materials is a solution to dramatically increase the load-carrying capacity of the structure. In this paper, a new design of auxetic-core cylindrical shells with carbon nanotube-reinforced coatings is presented. Additionally, the nonlinear buckling behaviors of auxetic-core cylindrical shells with carbon nanotube-reinforced coatings under axially compressive loads are investigated. Three distributed types of functionally graded carbon nanotube-reinforced coatings and the honeycomb lattice form of the auxetic core are investigated. The homogenization model for auxetic lattice structures is considered to constitute the formulations of stiffnesses of the core layer. The nonlinear basic formulations are formulated by using the geometrically nonlinear Donnell shell theory considering Pasternak’s foundation. The Galerkin procedure can be applied three times for three states of buckling behaviors, and the expressions of the compressive load-maximal deflection and compressive load-average end shortening postbuckling curves are achieved. The numerically obtained investigations present the significant effects of auxetic core, volume fraction, direction arrangement and distributed law of carbon nanotube, foundation stiffnesses, geometrical parameters of auxetic core and shell on the critical buckling load and postbuckling behavior of structures.

This paper presents a semi-analytical approach for investigating the nonlinear buckling and postbuckling of spiral corrugated sandwich functionally graded (FGM) cylindrical shells under external pressure and surrounded by a two-parameter elastic foundation based on Donnell shell theory. The improved homogenization theory for the spiral corrugated FGM structure is applied and the geometrical nonlinearity in a von Karman sense is taken into account. The nonlinear equilibrium equation system can be solved by using the Galerkin method with the three-term solution form of deflection. An explicit solution form for the nonlinear buckling behavior of shells is obtained. The critical buckling pressure and the postbuckling strength of shells are numerically investigated. Additionally, the effects of spiral corrugation in enhancing the nonlinear buckling behavior of spiral corrugated sandwich FGM cylindrical shells are validated and discussed.

Nonlinear buckling and postbuckling of longitudinally compressed carbon nanotube-reinforced (CNTR) cylindrical shells stiffened by longitudinal or circumferential CNTR stiffeners in thermal environments surrounded by elastic medium are presented in the present study. Five linear distributions of CNT are considered for the shell-stiffener structure system and they are modeled by innovation homogenization technique for CNTR stiffeners. Based on the classical Donnell thin shell theory with von Karman's nonlinearities and the Galerkin procedure, the governing equations can be built to analyze the critical buckling compression and postbuckling compression-deflection and compression-shortening behavior. The noticeable effects of volume fraction of CNTs, shell-foundation interaction stiffnesses, uniformly distributed temperature, and geometric properties of stiffened cylindrical shells on the critical buckling compression and compression-deflection and compression-shortening postbuckling behaviors of stiffened CNTR cylindrical shells are obtained and remarked in numerical examinations. INTRODUCTIONCarbon Nanotube (CNT) reinforced composite is known to be an advanced composite with high-performance material. The CNTs with the high aspect ratio, low density, exceptional, electro-thermo-mechanical properties can be used to enhance the electrical thermal, and mechanical properties of basic materials. By reinforcing the CNTs for the same directions into the isotropic material, Shen [1, 2], created the special type of CNT-reinforced (CNTR) composite with the functionally graded (FD) volume fraction of CNT in the thickness direction of shells. The longitudinally compressed CNTR cylindrical shells are the outstanding structures that were studied with different thermo-mechanically linear and nonlinear problems such as static buckling and postbuckling behaviors [1-3], combined loads of axial compression and external pressure [4], free and forced vibration responses [5][6][7], and dynamic stability [8][9][10][11][12]. The more complex load types as dynamical seismic loads applied for CNTR cylindrical shells were also considered and analyzed [13,14] taking into account the moisture and hygrothermal effects. An ideal for a CNTR composite material with the two-directional reinforcements of CNTs was presented [15,16] and nonlinear buckling of cylindrical

In Southeast Asia, climate change will potentially have negative consequences for urban transportation infrastructure (UTI). It is necessary to improve the understanding of climate change-associated loss and damage in relation to UTI to ensure the sustainability of existing transportation assets and for prioritizing future investments. However, there is currently limited knowledge on how to practically assess loss and damage for UTI in the context of climate change and then to incorporate appropriate adaptation measures and strategies to future-proof transportation planning. This study presents the results and experiences from assessing climate change-related loss and damage to UTI in six cities of Cambodia, Thailand and Vietnam. One pilot city from each country was selected for assessment by applying NK-GIAS software to determine loss and damage for urban roads. It was found that the six selected cities were highly vulnerable to climate change given their location and exposure to sea-level rise, storm surge, flooding, and salinity intrusion. Through analyses conducted using NK-GIAS software, economic losses for different flood scenarios were determined. The linkage between flooding and road damage was demonstrated, with maximum damage estimations under the most extreme flooding scenario of approximately 20 million USD for Hoi An, 3 million USD for Kampot and 21 million USD for Samut Sakhon, corresponding to water levels of 3.4 m, 4.0 m and 2.7 m respectively. Damage to the road network was identified as a key impact related to climate change. Further research is recommended to develop appropriate damage curves through laboratory analysis, addressing both flood depth and duration, to strengthen the NK-GIAS analyses undertaken in this study.