The disposal of used automobile tires is a major waste concern. Simply stacking tires and allowing them to decompose will harbor breeding mosquitoes that spread viruses, whereas burning them will release acidic and toxic gases. Therefore, one viable option is pyrolysis, where elevated temperatures are used to facilitate the decomposition of a material. However, the lack of theoretical support for pyrolysis technology limits the development of the pyrolysis industry when it comes to discarded tires. The purpose of this research is to put forward a brand-new multi-kinetic research method for studying materials with complex components through the discussion of various kinetic research methods. The characteristic of this kinetic research method is that it is a relatively complete theoretical system and can accurately calculate the three kinetic factors considered during the pyrolysis of multicomponent materials. The results show that the multi-kinetic research method can obtain the kinetic equation and reaction mechanism for the pyrolysis of tires with high accuracy. The pyrolysis process of this compound was divided into two stages, Reaction I and II, where the kinetic equation of Reaction I was f ( α ) = 0.2473 α − 3.0473 , with an activation energy of 155.26 kJ/mol and a pre-exponential factor of 5.88 × 109/min. Meanwhile, the kinetic equation of Reaction II was f ( α ) = 0.4142 ( 1 − α ) [ − ln ( 1 − α ) ] − 1.4143 , while its activation energy was 315.40 kJ/mol and its pre-exponential factor was 7.86 × 1017/min. Furthermore, based on the results of the research analysis, the reaction principles corresponding to Reaction I and Reaction II in the pyrolysis process of this compound were established.

Purpose This study aims to monitor and guide the assembly process. The operators need to change the assembly process according to the products’ specifications during manual assembly of mass customized production. Traditional information inquiry and display methods, such as manual lookup of assembly drawings or electronic manuals, are inefficient and error-prone. Design/methodology/approach This paper proposes a projection-based augmented reality system (PBARS) for assembly guidance and monitoring. The system includes a projection method based on viewpoint tracking, in which the position of the operator’s head is tracked and the projection images are changed correspondingly. The assembly monitoring phase applies a method for parts recognition. First, the pixel local binary pattern (PX-LBP) operator is achieved by merging the classical LBP operator with the pixel classification process. Afterward, the PX-LBP features of the depth images are extracted and the randomized decision forests classifier is used to get the pixel classification prediction image (PCPI). Parts recognition and assembly monitoring is performed by PCPI analysis. Findings The projection image changes with the viewpoint of the human body, hence the operators always perceive the three-dimensional guiding scene from different viewpoints, improving the human-computer interaction. Part recognition and assembly monitoring were achieved by comparing the PCPIs, in which missing and erroneous assembly can be detected online. Originality/value This paper designed the PBARS to monitor and guide the assembly process simultaneously, with potential applications in mass customized production. The parts recognition and assembly monitoring based on pixels classification provides a novel method for assembly monitoring.

Purpose – The purpose of this paper is to use rapid prototyping (RP) technology to build physical models based on axisymmetric finite element (FE) simulation deformation results. To this end, an algorithm which extracts stereolithography (STL) model from axisymmetric ring element mesh is developed and realized by MATLAB programming. Design/methodology/approach – The algorithm first identifies boundary element edges, which compose the contour(s) of an axisymmetric ring FE mesh. Then, the identified contour edges are around the symmetry axis revolved a specific angle, at certain intervals according to certain approximate criterion, to generate new nodes to form a group of oriented triangles whose normal vectors conform to the right-handed rule. Finally, a completely closed STL model is obtained by necessary triangulation processing and rotation mapping based on original mesh. Findings – It is validated that the extracted STL model is sound and the proposed algorithm is feasible, right and characterized by linear time complexity for extracting STL model from either triangular, quadrilateral, or mixed triangular/quadrilateral axisymmetric mesh. Research limitations/implications – Color is important for expressing FE simulation results, which is not involved in STL model. Among the alternative data file formats, VRML representation is an applicable one that is complimentary to existing RP processes and suitable for color 3D printing. Based on the current work, coloring VRML model could be extracted from axisymmetric FE simulation results conveniently. Originality/value – The study of this paper provides a RP-based materialized mode to characterize axisymmetric FE simulation deformation results, which is more intuitive and visible than the computer graphics-based visualization.

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