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Obtaining insights on the illicit consumption of endangered wildlife products is challenging, especially when the study objects are the super-rich. This research note draws upon my experience interviewing nearly 1,000 rhino horn consumers in Vietnam. Trust is crucial in such interactions. No interviews could have been conducted without good rapport between interviewers and respondents. Nonetheless, soliciting interviews requires skills that one cannot expect to teach enumerators in the short term. This includes a winning sense of humour, colourful life experience, and true grit. Once good rapport is established, the use of specialised questionning techniques or bias-mitigation tools becomes unnecessary. Instead I suggest a practical approach to study consumers of illegal and luxury wildlife products in an Asian context.

This study explored the influencing factors of attitudes towards traffic safety and risky driving behaviours amongst a sample of 594 e-bike riders who are high-school students in Vietnam. By using structural equation modelling, this research confirmed the significant association between traffic safety attitudes and the behaviours as well as the significant influence of traffic risk perception and safety knowledge on the traffic safety attitudes. In addition, e-bike riders’ behaviours were also significantly affected by descriptive norm. Furthermore, considering the specific characteristics of e-bike riders who are high-school students, this study found that either higher level of perceived family’s commitment to traffic safety or lower level of perceived privilege of e-bike riders who are high-school students significantly associated to both safer traffic safety attitudes and less risky driving behaviours.

An analytical approach for nonlinear thermo-mechanical buckling of functionally graded graphene platelet reinforced composite (FG-GPLRC) circular plates and shallow spherical shells resting on nonlinear elastic medium using the higher-order shear deformation theory (HSDT) and the nonlinearities of von Kármán is established in the present work. Assuming that the structures are axisymmetrically displaced for the central axis and external pressure and thermal loads are applied. The nonlinear elastic medium is used to model the behaviour of hardening or softening medium depending on the positive and negative values of the nonlinear parameter, respectively. By applying the Ritz energy method, the relation expressions of load-deflection are archived to investigate the postbuckling response and critical buckling load of the structures. Special effects on the nonlinear thermo-mechanical behaviour of plates and shells with different medium stiffnesses, different material parameters, and different geometrical dimensions are explored and discussed in numerical results. [ABSTRACT FROM AUTHOR]

An analytical approach for nonlinear buckling and postbuckling responses of corrugated-core toroidal shell segments with carbon nanotube (CNT) reinforced face sheets in thermal environment subjected to radial pressure is reported in this work. Three distribution laws of functionally graded CNT-reinforced layers and the trapezoidal and round forms of the corrugated core are investigated. An equivalent technique for corrugated panels is improved by adding thermal forces to model the behavior of the corrugated core. The nonlinear equations are formulated by using the geometrically nonlinear Donnell shell theory considering Pasternak's foundation. An algorithm to solve a system of nonlinear equations is established using the Ritz energy method with three shell deflection amplitudes. The postbuckling expressions between the compressive and tensile loads with maximal deflection and the critical compressive and tensile loads are determined. The numerically investigated examples present the significantly beneficial effects of corrugated core and functionally graded CNT-reinforced face sheets on nonlinear buckling responses of structures. [ABSTRACT FROM AUTHOR]

This article has been retracted. A retraction notice can be found at https://doi.org/10.3233/JIFS-219433. [ABSTRACT FROM AUTHOR]

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.

The main aim of this paper is to investigate the postbuckling and buckling of functionally graded graphene-reinforced composite (FG-GRC) laminated cylindrical shells strengthened by stiffeners under axial compression with the uniform temperature change effect. The stiffener design option for FG-GRC cylindrical shells under axial compression is presented and a suitably smeared stiffener technique for GRC laminated stiffener system is developed. Basing on the von Kármán Donnell shell theory, the Galerkin's procedure, and the three-term solution of deflection, the explicit forms of critical buckling and expression of load-deflection postbuckling curves relation are obtained. Effects of the GRC laminated stiffeners, the environment temperature, the graphene-reinforced parameters on the compressed buckling behavior are validated. [ABSTRACT FROM AUTHOR]

The buckling and nonlinear postbuckling analysis of toroidal shell segments with auxetic-core layer and Graphene-reinforced polymer coatings under torsional loads is reported in the present research. The functionally graded Graphene-reinforced polymer coatings are considered with three distribution laws, and the auxetic cores are designed in the honeycomb lattice forms. An auxetic homogenization technique is applied to establish the stiffness terms of the auxetic core. The combination of nonlinear von Karman Donnell shell theory and the Stain and McElman approximate is applied to formulate the nonlinear equilibrium equations of shells with the shallow longitudinal curvature considering the two-parameter foundation model. The deflection of shells is assumed to be a three-term form corresponding to the pre-buckling, linear and nonlinear postbuckling behaviors, and the Galerkin method is employed for three terms of defection. The torsion-deflection and torsion-twist angle postbuckling behaviors can be obtained in explicit forms. The numerical examinations validate the large effects of honeycomb lattice auxetic core, the functionally graded Graphene-reinforced polymer coatings, the parameters of shell's geometric and foundation on the nonlinear buckling behaviors of shells. [ABSTRACT FROM AUTHOR]

There are many beam models to simulate the variable thickness functionally graded material (FGM) beam, each model has advantages and disadvantages in computer aided engineering of the mechanical behavior of this beam. In this work, a new model of beam is presented to study the mechanical static bending, free vibration, and buckling behavior of the variable thickness functionally graded material beams. The formulations are based on modified first order shear deformation theory and interpolating polynomials. This new beam model is free of shear-locking for both thick and thin beams, is easy to apply in computation, and has efficiency in simulating the variable thickness beams. The effects of some parameters, such as the power-law material index, degree of non-uniformity index, and the length-to-height ratio, on the mechanical behavior of the variable thickness FGM beam are considered.