Experimental Investigation of Bubble Migration near Anisotropic Beams

In order to resist bubble loading, anisotropic composite materials are the development direction of the future. The objective of this paper was to experimentally investigate the hydrodynamic performance of anisotropic laminate composite plates, with a focus on the effect of its anisotropic characteristics on single bubble migration. In these experiments, the bubble was generated in a transparent water tank filled with sufficiently degassed water by Joule heating at the connecting point of the electrodes through the discharge of a 6600 μF charge to 800 V, and a high-speed camera system with a recording speed of 40,000 frames per second was used to record the temporal evolution of bubble patterns and the dynamic responses of the laminated composite plates. The results are presented for two anisotropic cantilever composite beams with different ply angles, namely, 0° and 30°. Several variables, such as the shapes of the bubble, the curved trail of motion of the bubble center, bubble collapse time, and bubble initial standoff distances were extracted from the photographic images. The results showed that bubble migration near the 30° plate presents a curved bubble trail with an evident tilted angle during the collapse and rebound stages, which is very different from bubbles that all move vertically above the 0° plate. Furthermore, a characterization method for bubble migration was proposed to quantitatively describe the curved bubble trails and the deformation of the composite beams in temporal and spatial scales. This method shows that the curved bubble trails near the 30° plate are closely related to the dynamic response of composite beams, with a focus on the bending-twisting coupling effect

Identifying the functional form and operation rules of energy storage pump for a hydro-wind-photovoltaic hybrid power system

Coupling energy storage pumps with conventional hydropower plants is one of the most valuable methods to increase the consumption rate of renewable energy. There are few small-scale hybrid power systems configurating energy storage pumps in the world (e.g., Ikaria Island, Greece). However, whether the operating principle and configuration method are feasible and transferable for a large-scale renewable energy base is unclear. This study proposes specific operating principles and configuration method for a large-scale hybrid power system, demonstrating the feasibility by investigating typical scenarios of an engineering case in Qinghai Province, China. Assume the conventional hydropower plants, wind farms, and PV stations in the case are constructed and in operation completely. The configuration relationship between energy storage pump and hydropower is investigated by setting the unit of energy storage pump from 1 to 50, the per-kW investment cost from CNY5000/kW to CNY30000/kW under the constraint of individual capacity of 100 MW. Furthermore, the economic indicators of internal rate of return and dynamic payback period are introduced to evaluate the performance of the whole hybrid power system. The configuration consequence of 18–21 pumps shows a good relation with renewable energy. This study provides theoretical and technical support for planning relevant hybrid power station projects

Admission D-dimer testing for differentiating acute aortic dissection from other causes of acute chest pain

Introduction : The present study aims to evaluate the utility of D-dimer testing for differentiating the causes of acute chest pain, including acute aortic dissection (AAD), pulmonary embolism (PE), acute myocardial infarction (AMI), unstable angina (UA), and other uncertain diagnoses of chest pain. Material and methods : Consecutive patients admitted for acute chest pain within 24 h from symptom onset were enrolled prospectively, and plasma D-dimer levels were measured on admission. Diagnoses of AAD, PE, AMI, and UA were confirmed by standard methods. Results : A total of 790 patients were enrolled, including 202 AAD, 43 PE, 315 AMI, 136 UA, and 94 cases of other uncertain diagnoses. D-dimer levels were significantly higher in patients with AAD and PE than in those with AMI, UA, and other uncertain diagnoses (p < 0.001), but they were comparable between patients with AAD and PE (p = 0.065). Moreover, patients with type A AAD had higher D-dimer levels than those with type B AAD (p = 0.022). Receiver operating characteristic (ROC) curve analysis showed that a D-dimer level < 0.5 µg/ml was a good predictor for ruling out AAD, with a sensitivity of 94.0% and a specificity of 56.8%. At a cut-off level of 0.5 µg/ml, the negative and positive likelihood ratios were 0.10 and 2.18, respectively, with a positive predictive value of 42.6% and a negative predictive value of 96.6%. Conclusions : The D-dimer level within 24 h after symptom onset might be helpful for differentiating AAD from other causes of chest pain

Association between soybean product consumption and executive function in Chinese Tibetan children and adolescents

ObjectiveThis sought to explore the association between soybean product consumption and executive function (EF) in Chinese Tibetan adolescents in high-altitude areas.MethodsA total of 1,184 Tibetan children and adolescents were tested on demographic variables, soybean product consumption, and executive function in Lhasa and Nagchu regions of Tibet, China, using stratified whole population sampling. One-way ANOVA, linear regression analysis, and logistic regression analysis were used to analyze the associations existing between soybean product consumption and executive function.ResultsThe proportions of Hardly ever, Occasionally, and Often in Soy Consumption among Tibetan children and adolescents in high altitude areas of Tibet, China were 21.7, 50.3, and 28.0%, respectively. The difference in 2 back reaction time among Tibetan children and adolescents with different soybean product consumption was statistically significant (F = 6.374, p = 0.002). The difference in conversion function reaction time was also statistically significant (F = 8.129, p &lt; 0.001). Taking the soybean product consumption ≥6 t/w group as the reference group, after adjusting the relevant factors, those with soybean product consumption ≤1 t/w showed a statistically significant increase in Inhibit Function Dysfunction (OR = 1.844, 95% CI: 1.152, 2.951) and Conversion Function Dysfunction (OR = 2.008, 95% CI: 1.106, 3.646) had an increased risk of Conversion Function Dysfunction (OR = 2.008, 95% CI: 1.106, 3.646), which was significantly different (p &lt; 0.05).ConclusionThere is an association between soybean product consumption and inhibitory control and translational flexibility of brain executive functions in Chinese Tibetan children and children and adolescents at high altitude

Comparison of growth and nutritional status of Chinese and Japanese children and adolescents

Background The difference in growth and nutritional status, both important indices of population quality, between Chinese and Japanese children and adolescents is unknown. Aim This study aimed to compare growth and nutritional status between Chinese and Japanese children and adolescents. Subjects and methods The height-for-age and BMI-for-age distribution of 9,226 children and adolescents aged 7–18 years from China and Japan were described with the Lambda Mu and Sigma method. Wasting, overweight and obesity were evaluated based on BMI-for-age cut-offs of the 2007 WHO Child Growth Reference. Results For boys, the overall average height, weight and BMI of Chinese participants were 3.0 cm, 4.8 kg and 1.2 kg/m2 greater compared with Japanese participants, respectively; for girls, these were 4.6 cm, 3.9 kg and 0.6 kg/m2, respectively. Compared with Japanese children, the 3rd, 50th and 97th percentiles of height-for-age, 1Z-score, and 2Z-score of BMI-for-age of Chinese children were greater, whereas the minus 2Z-scores of Chinese children were less. The prevalence of wasting, overweight and obesity among Chinese participants was greater. Conclusions Compared with Japanese children, Chinese children tended to be taller. The worrying burden of overweight, obesity and wasting was recognised among Chinese children