Search results

This paper aims to propose a diverless weld bead maintenance welding technology to prevent the leakage of subsea oil and gas pipeline and solve the key problems in the maintenance of subsea pipeline.

Based on the analysis of the cross-section of the fillet weld, the multi-layer and multi-pass welding path planning of the submarine pipeline sleeve fillet weld is studied, and thus a multi-layer and multi-pass welding path planning strategy is proposed. A welding seam filling method is designed, and the end position of the welding gun is planned, which provides a theoretical basis for the motion control of the maintenance system.

The trajectory planning and adjustment of multi-layer and multi-pass fillet welding and the motion stability control of the rotating mechanism are realized.

It provides the basis for the prototype design of the submarine pipeline maintenance and welding robot system, and also lays the foundation for the in-depth research on the intelligent maintenance system of submarine pipeline.

The maintenance of diverless subsea pipeline is a new type of maintenance method, which can solve the problem of large amount of subsea maintenance work with high efficiency.

The purpose of this paper is to investigate international students’ willingness to communicate (WTC) in US university classrooms, focusing on the role of classroom environment. International students in higher education have great economic and academic impacts, studying their WTC in classrooms facilitates their learning and speaking of English and helps them better participate in class activities and acclimatize to schooling in their adopted cultures.

Survey data were collected from 50 Chinese undergraduate students who took English as a second language (ESL) class at a large Midwestern university. Four students participated in follow-up interviews.

Results revealed that in ESL classrooms, confidence and motivation had a direct impact on WTC, classroom environment had an indirect effect on WTC through the mediation of motivation and confidence. Qualitative analysis also showed that classroom environment greatly impacted WTC in both ESL and general classrooms, and teacher factors were most important.

These results have direct pedagogical implications for teachers serving international students in higher education.

This study facilitates the understanding of the previously under-studied influence of classroom environments on WTC, which has direct pedagogical implications. WTC research focuses predominantly on language learning classrooms, this study initiates an extended exploration of WTC in language learning as well as general classrooms.