UG-based research and development of 3D pipe layout system of the aircraft engine

AbstractStandardized design method is important for the airworthiness certification. Based on the principles and features of the aircraft engine external pipe system, in this paper, the research on the theory of automation of pipe layout has been done. We also put forward the process of automatic and mixed generation of pipe layout, the design of pipe layout system and the resolution of arbitrariness of pipe layout. In order to improve the efficiency of the system, a parameterized component library has been built, on the basis of the secondary development of UG. Therefore, the automation pipe layout and the real-time modification have been achieved. According to the predefined rules, constraint test and result output of the system can be conducted

Spanning the Boundary: Measuring the Realized and Lifecycle Impact of Distinct Boundary Spanning Activities on Project Success and Completion

For work teams to be effective, maintaining communication ties with other individuals and teams elsewhere in the organization—an activity typically referred to as team boundary spanning—is necessary for obtaining resources critical to project success. Within the literature on boundary spanning, the positive relationship between a team’s boundary-spanning activities and their performance has been validated repeatedly, but primarily through the use of self-reports from managers and team members. Thus, neither objective data exists to support these claims nor a longitudinal understanding of how various boundary-spanning activities may play different roles at various stages of project work. Similarly, with the proliferating use of enterprise social media (ESM) technologies in organizations, the empirical link between the increased visibility of communication ties in ESM and more effective boundary spanning has been largely assumed, but has received only limited empirical validation. In this study, drawing on log and content data from 169 projects in an ESM of a large multi-national corporation, we aim to objectively assess the effect of boundary spanning on project success as well as provide a qualitative path model of the evolution of boundary-spanning activities throughout the lifecycle of a project through a comparison of successful versus unsuccessful projects. Implications for theory and practice are discussed

Intra-Organizational Boundary Spanning: A Machine Learning Approach

With the ubiquity of data, new opportunities have emerged for the application of data science and machine learning approaches to help enhance the efficiency and effectiveness of knowledge management. With the growing use of social media technologies in enterprise settings, one specific area of knowledge management warranting the use of big data analytics involves cross-boundary knowledge creation and management. The objective of this paper is to develop and test a machine learning approach that can assist knowledge managers in detecting three types of intra-organizational boundary spanning activities with the goal of predicting and improving such important outcomes as team effectiveness, collaboration, knowledge sharing, and innovation

Case report: Thymoid differentiated carcinoma of thyroid: Two cases

ObjectiveThymoid carcinoma of the thyroid gland is a rare thyroid tumor, which is often presented in case reports.MethodsThe clinical data of two patients with thymic carcinoma of the thyroid gland were retrospectively reviewed.ResultsCase 1: a middle-aged woman who was admitted to the hospital because of “progressive enlargement of the anterior cervical mass for 8 months.” Color Doppler ultrasound and CT showed malignant tumor with high possibility of bilateral cervical lymph node metastasis. Total thyroidectomy and bilateral central cervical lymph node dissection were performed. Lymph node biopsy showed the metastasis of small cell undifferentiated thyroid carcinoma. Because the biopsy pathological result was not consistent with the pathology of the primary lesion, immunohistochemistry was performed again, and the final diagnosis was thymic carcinoma in the thyroid gland. Case 2: the patient was an elderly man who was admitted to the hospital due to hoarseness for half a month. During the operation, the tumor invaded the trachea, esophagus, internal jugular vein, common carotid artery, and surrounding tissues. Palliative resection of the tumor was performed. The tumor postoperative pathology suggested thymoid carcinoma of the thyroid gland. It recurred and compressed the trachea 4 months after the operation, resulting in dyspnea of the patient, and finally tracheotomy was performed to alleviate the symptoms.ConclusionCase 1 showed multiple differences in pathological diagnosis, suggesting that the lack of specific imaging and clinical manifestations of thymoid-differentiated thyroid carcinoma made the diagnosis so difficult. Case 2 progressed rapidly, suggesting that thymoid-differentiated thyroid carcinoma was not always inert, and the treatment and follow-up should follow the principle of individualization

Pressure measurement based on multi-waves fusion algorithm

Measuring the pressure of a pressure vessel accurately is one of fundamental requirements of the operation of many complex engineering systems. Ultrasonic technique has been proposed to be a good alteration of non-intrusive measurement. Based on the study of acoustoelastic effect and thin-shell theory, it has been identified that the travel-time changes of the critically refracted longitudinal wave (LCR wave) and other reflected longitudinal waves are all proportional to the inner pressure. Considering the information redundancy in these waves, we proposed an approach for pressure measurement by using the information fusion algorithm on multiple reflected longitudinal waves. In the paper, we discussed the fusion algorithm in details and proposed a pressure measurement model, which represents an accurate relationship between the pressure and the travel-time changes of multiple waves. Through the experiment, the analysis of data collected from experiment system showed that the pressure measurement based on the multi-wave model is notably more accurate than the one based on the single-wave model (the average relative error (ARE) can be less than 7.24% and the root-mean-square error (RMSE) can be lower than 0.3MPa)

New hanger design approach of tied-arch bridge to enhance its robustness

As the crucial components among the tied-arch bridge, the local failure of hangers may trigger a progressive collapse through the entire tied-arch bridge. However, the current design guidance as regards hangers still lacks consideration of structure robustness under an extreme hazard. To improve the structural robustness of tied-arch bridge under extreme conditions, a new hanger design method is proposed, which is termed as asymmetric parallel double-hanger system. Based on Miner’s linear cumulative damage law, an analysis on the fatigue life of the double-hanger system was conducted to verify the feasibility of the proposal, and then a dynamic time-history analysis was employed to simulate the transitory fracture impact due to one or more hangers fracturing. According to the simulation results, the structural robustness is greatly enhanced with asymmetric parallel-double hanger system design, when compared with single hanger system design. When one or more hangers reveal local damage, it will not trigger a progress failure to the whole structure in particular. Several practical suggestions of bridge system’s load-carrying capacity are also put forward for the future arch bridge design at the end of this paper. © 2018 Korean Society of Civil Engineer