Ye-Lin, Y.Martinez-De-Juan, J. L.Jareno-Silvestre, A.Prats-Boluda, G....
9页
查看更多>>摘要：Electrogastrography has emerged as a non-invasive technique for diagnosing an extensive variety of gastrointestinal disorders. The non-invasive electrogastrogram (EGG) remains a challenge due to the poor spatial resolution of conventional disk electrodes. In this work we attempted to determine the possibility of detecting gastric myoelectric activity using concentric ring electrodes (CRE) proposed to improve the spatial resolution of bioelectrical recordings. We simultaneously recorded 8 bipolar and bipolar concentric (BC) EGGs acquired by disk electrodes and CREs, respectively. The BC EGG showed lower signal amplitude than the bipolar recordings but were less influenced by cardiac interference and had a slow wave (SW) detectability above 80% when positioned over the stomach. We found a similar gastric SW frequency in both bipolar and BC EGG records in both fasting and postprandial states and a similar postprandial/fasting power ratio, suggesting the feasibility of using CRE to identify gastric myoelectric activity.
查看更多>>摘要：This work aims to investigate the macro-meso failure and instability mechanism of cavity-contained granite subjected to increasing-amplitude and decreasing-frequency cyclic loads combined with acoustic emission (AE) and X-ray computed tomography (CT) technique. Testing results show the cavity orientation affects rock lifetime, strength, deformation, damping ratio, AE activities and the internal failure pattern. The sudden increase of volumetric strain and abrupt decreases of b-value and damping ratio can issue the fast damage propagation, and their relationships were established. The rock having high cavity orientation has lower AE b-value, volumetric strain and damping ratio. A damage evolution model considering the damage accumulation was proposed based on AE energy that can well fit the experimental data. Post-test CT images highlight the influence of cavity orientation on rock internal failure modes. It is found that shear failure is liable to occur for rock having high cavity orientation.
查看更多>>摘要：The objective of this review was to evaluate current studies that addressed the use of sensors in stored grains, Intenet of Things (IoT) precepts and Machine Learning (ML) technologies in post-harvest to identify resources and new possibilities for technological development that can help in the monitoring the quality of stored grains. The review results demonstrated the wide application of sensors and devices to gather information in real-time based on the basic principles of good grain management and computational data analysis tools. It was verified that the results collected in real-time enable better decision-making in situations where there is a risk of loss and deterioration of stored grain due to variationsin factors like water content, grain mass temperature and relative humidity intergranular air. Thus, the quality of stored grain can be predicted by the equilibrium moisture content and CO2 concentration monitoring in the intergranular air.
查看更多>>摘要：The pressure comfort of a high-speed train is closely related to the static and dynamic airtightness performance of the train carriage, and this performance is studied mainly with field surveys and tests on full-scale trains. Considering the high cost and difficulty of full-scale tests, the applicability of the reduced-scale model experiment method in the study of train carriage airtightness performance is worth exploring. In this study, a power-law relationship between the scale factors and static airtightness coefficients of carriage models was first established using numerical simulations, to determine the fundamental theoretical support for the reduced-scale model experiments. A series of static and moving model experiments were conducted on a newly designed 1/20th-scale special train carriage model. The static airtightness coefficients obtained from static model experiments showed a discrepancy less than 5% to their theoretical values, which revealed the experimental feasibility of the reduced-scale model for studying the static airtightness performance. The pressure spectrum characteristics of the measured pressure from the moving model experiment indicated that not only the high-intensity aerodynamic alternating pressure load with a frequency peak around St = 1.76 but also the high-frequency mechanical vibrations around St = 17.03 from the wheel-rail coupling system were experienced by the carriage body traveling through a tunnel, which might cause some potential leakages to appear on the carriage body. This provides a new understanding of the potential causes of the deterioration of the train's dynamic airtightness performance.
NSTL
Elsevier