Self-determination theory is a psychological theory proposed by American psychologists and is widely used in research in the field of education. Mobile applications are gradually changing the traditional classroom communication mode between teachers and students with their intelligent, portable, and humanized operation. Deep integration of information technology and education teaching, promoting mobile applications into the teaching process, facilitating local colleges and universities to better achieve the cultivation goal of high-quality application-oriented talents, and exploring a new learner-centered classroom teaching model are hot issues of current research in the education field. The flipped classroom and mobile application were effectively combined, and a flipped classroom model based on mobile application was proposed and implemented. Based on self-determination theory, this study investigates the current situation of students' basic psychological needs satisfaction and classroom satisfaction under the flipped classroom model based on mobile applications and explores the relationship between the students' basic psychological needs satisfaction and classroom satisfaction. A total of 151 local college students in different professional fields participated in the questionnaire survey. The research results reveal that in the flipped classroom model based on mobile applications, the students' basic psychological needs satisfaction and classroom satisfaction are at a high level, and the two are significantly positively correlated. Therefore, the students' basic psychological needs affect their satisfaction with the classroom, which provides some references for the smooth implementation and further promotion and application of the classroom teaching model.

Loess cave dwellings are the most typical style of regional architecture in northwest China; now, there are still tens of millions of people living in them. The northwest is an earthquake-prone area, and cave dwellings have suffered a lot of damage in previous moderate and strong earthquakes, so their earthquake resistance has attracted people’s attention. At present, the seismic analysis of aboveground building structures is relatively mature, while the seismic analysis of loess cave dwellings is less researched. To study the seismic response of loess cave dwellings, a single-hole cliff-side loess cave dwelling located in Yangjialing revolution former sites of Yan’an City of northwest China was investigated and surveyed; the three-dimensional numerical model was established by MIDAS/GTS NX. Combining the historic earthquake damage investigation, dynamic time-history analysis of the single-hole loess cliff-side cave dwelling subject to four horizontal earthquake actions was conducted to determine the weak positions, failure characteristics, and the corresponding displacement and stress of the loess cave dwelling under earthquake load. The results show that the loess has an amplification effect on the seismic waves, the arch vault is a key factor to the stability of the loess cave dwellings, the cliff-side loess cave dwellings in an 8-degree area cannot be used to continue living, and the entrance to loess cave dwellings is the most dangerous place when the earthquake happens.

The cave dwelling is one of the most typical traditional dwellings and green building forms in the Loess Plateau of Northern Shaanxi. The construction of the cave dwelling was built only based on the experience passed down by predecessors, without the guidance of formal design theories and calculation methods, and the overall safety of the cave-dwelling structure needs to be solved urgently. To make the mechanical analysis model closer to the actual force of the masonry cave dwelling, it is proposed to simplify the arch ring in the masonry cave-dwelling structure into an unhinged arch mechanical calculation model. Applying the theory of elastic center to the force method calculation in structural mechanics, the force of the cave-dwelling structure is analyzed and compared with the force results of the three-hinged arch calculation model, so as to determine the correctness and reliability of the calculation diagram of the unhinged arch. The conclusions indicate it is correct and reliable to use the unhinged arch calculation model, which is closer to the actual force situation, to calculate the forces of the arch rings in masonry cave dwellings, and both the three-hinged arch and unhinged arch models are feasible to be applied to the mechanical analysis of the arch rings. The unhinged arch calculation model is more reliable and safer in the design and calculation of the cave-dwelling leg components compared with the three-hinged arch calculation model because it considers the bending moment at the arch foot support. The research results can be used to improve the structural design data of the cave dwelling and provide theoretical guidance for the construction, repair, and protection of the cave dwelling.

Engineering education is increasingly expected to prepare graduates capable of addressing sustainability challenges, public safety concerns, and ethical responsibilities. However, in many civil and environmental engineering curricula, sustainability and ethics are still treated as supplementary topics rather than being systematically embedded in core technical courses. This study reports a sustainability-oriented curriculum reform implemented in a Building Water Supply and Drainage Engineering course, integrating Education for Sustainable Development (ESD) principles into CDIO-aligned project-based learning activities. A single-group pre–post quasi-experimental design was adopted with 100 undergraduate students. Quantitative data were collected using a competency-based questionnaire, and paired-sample t-tests, effect sizes, and 95% confidence intervals were applied to examine changes in students’ self-reported competencies. Qualitative data were obtained from reflective learning reports and analyzed through thematic analysis. The results indicate statistically significant improvements in sustainability awareness, ethical and professional responsibility, human-centered design, and systems thinking, with large effect sizes. These findings provide context-specific descriptive evidence supporting the feasibility of embedding sustainability and ethical responsibility within discipline-specific technical engineering courses. Nevertheless, the absence of a control group and the reliance on self-reported measures limit causal interpretation. Future research is recommended to adopt comparative or longitudinal designs and incorporate more objective performance-based assessments.

Engineering education faces growing demands to prepare graduates capable of addressing complex sustainability challenges, public safety concerns, and ethical responsibilities. However, sustainability and ethical education are often delivered as supplementary content, limiting their integration with core engineering instruction. This study examines and evaluates a curriculum reform of a Building Water Supply and Drainage Engineering course that systematically integrates sustainability, ethical responsibility, and human-centered values into technical teaching through a CDIO-oriented approach. A quasi-experimental pre–post design was employed with a full cohort of 100 undergraduate engineering students. Data were collected using a sustainability-oriented questionnaire, project-based assessment rubrics, and student reflection reports. Quantitative data were analyzed using paired-sample t-tests and effect size calculations, while qualitative data were thematically coded to support interpretation of the results. The findings demonstrate statistically significant and practically meaningful improvements in students’ sustainability awareness, ethical responsibility, human-centered design thinking, and systems thinking. Project assessment results further reveal students’ ability to apply sustainability principles and ethical considerations in engineering design tasks. These results provide empirical evidence that value integration within core engineering courses enhances both technical competence and professional responsibility. This study contributes empirical evidence to Education for Sustainable Development in engineering education by demonstrating a transferable pedagogical model that embeds sustainability and ethics into discipline-specific engineering instruction without increasing curricular load.

The freestanding stone cave-dwelling is a kind of arched and sheltered house built with stones in the Loess Plateau region of northwest China. Amazingly, before construction, this kind of cave-dwelling was not formally calculated and designed in theory, but only built on the experience passed down by predecessors. The arch ring is the main load-bearing component of the freestanding stone cave-dwelling, through which the upper loads are transmitted to the legs on the left and right sides of the cave-dwelling and then to the foundations. Therefore, it is a prerequisite to ensure the safety of cave dwellings by adopting a reasonable and accurate mechanical calculation model for the arch ring of a stone cave-dwelling to reveal the distribution of internal forces in the arch ring and scientifically design the arch ring accordingly. Three mechanical calculation models (structural calculation diagrams) are adopted for the arch ring of stone cave-dwelling, namely, hingeless arch, two-hinged arch, and three-hinged arch. Based on the force equilibrium and the force method from the structure mechanics, the formulae for calculating the internal force of the stone arch ring under these three different mechanical calculation models are derived respectively. The mechanical calculation results of three calculation models are compared and analyzed to clarify the difference and rationality of the stress results of the arch ring under the three mechanical calculation models and the degree of influence on the force of the lower cave-dwelling leg members. Lastly, in accordance with the internal force calculation results, the calculation formulae for the design of the arch ring thickness are proposed. The study shows that the hingeless arch and two-hinged arch models are more consistent with the actual failure characteristics, two-hinged arch calculation model is safer, more accu-rate, and more reliable than the hingeless arch calculation model when it is used in the mechanical analysis of circular arc arch ring. The findings are intended to serve as theoretical references for the design and construction, protection and reinforcement, and sustainable development and inheritance of cave dwellings in the future.