The Effect of the Inlet Total Pressure and the Number of Detonation Waves on Rotating Detonation Engines

AbstractThis paper presented a three-dimensional numerical study of rotating detonation engines, exploring the effect of the inlet total pressure and the number of detonation waves on the performance of rotating detonation engines. It was found that under the same total pressure of the inlet fuel, the number of detonation waves had little influence on the specific impulse, the thrust and the outlet flow of RDE. The number of detonation waves, however, affected the time needed to reach stable detonation.Besides, there was instability phenomenon in the development of detonation waves due to the relation between the number of detonation waves and the inlet total pressure. In order to speed up the process from ignition to stable detonation, the total pressure of the inlet fuel should match with the ignitions

Vibration-induced pressures on a cylindrical structure surface in compressible fluid

This paper unprecedentedly addresses the effect of vibrations of a cylindrical structure on dynamic pressures in a compressible and incompressible fluid situation. To obtain analytical solutions, the density of the fluid is simplified as a constant, but the rates of the density with respect to time and to space are considered as a dynamic and time-dependent function. In addition, the low velocity of the vibration is taken into account so the lower order terms are negligible. According to the assumption that the vibration at the boundary of the structure behaves as a harmonic function, some interesting and new analytical solutions can be established. Both analytical solutions in the cases of the compressible and incompressible fluid are rigorously verified by the calibrated numerical simulations. New findings reveal that, in the case of the incompressible fluid, dynamic pressure at the surface of the cylindrical shell is proportional to the acceleration of the vibration, which acts like an added mass. In the case of the compressible fluid, the pressure at the surface of the cylindrical structure is proportional to the velocity of the vibration, which acts as a damping. In addition, the proportional ratio is derived as ρ c

Crystal structure of N′ -(2, 6-dimethyl-phenyl)benzenecarboximidamide tetrahydrofuran monosolvate

Acknowledgements This work was supported by grants from the Natural Science Foundation of China (grant No. 20702029) and the Natural Science Foundation of Shanxi Province (grant No. 2008011024).Peer reviewedPublisher PD

Dynamic Pressure Analysis of Hemispherical Shell Vibrating in Unbounded Compressible Fluid

This paper is the first to highlight the vibrations of a hemispherical shell structure interacting with both compressible and incompressible fluids. To precisely calculate the pressure of the shell vibrating in the air, a novel analytical approach has been established that has existed in very few publications to date. An analytical formulation that calculates pressure was developed by integrating both the ‘small-density method’ and the ‘Bessel function method’. It was considered that the hemispherical shell vibrates as a simple harmonic function, and the fluid is non-viscous. For comparison, the incompressible fluid model has been analyzed. Surprisingly, it is the first to report that the pressure of the shell surface is proportional to the vibration acceleration, and the velocity amplitude decreased at the rate of 1 r 2 when the fluid was incompressible. Otherwise, the surface pressure of the hemispherical shell was proportional to the vibration velocity, and the velocity amplitude decreased with the rate of 1 r when the fluid was compressible. The compressibility of fluid played an important role in the dynamic pressure of the shell structure. Furthermore, the scale factor derived by the theoretical approach was the product of the density and the sound velocity of the fluid ( ρ o c ) exactly. In this study, the analytical solutions were verified by the calibrated numerical simulations, and the analytical formulation were rigorously tested by extensive parametric studies. These new findings can be used to guide the optimal design of the spherical shell structure subjected to wind load, seismic load, etc

Photometric observations of flares on AD Leo from GWAC-F30 and TESS

We observed active M dwarf star AD Leo for 146 hr in photometry by GWAC-F30 and also analyzed 528-hr photometric data of the star from TESS. A total of 9 and 70 flares are detected from GWAC-F30 and TESS, respectively. Flare durations, amplitudes and energies are calculated. The distributions of the three properties and FFDs are given. Within the same energy range of flares, the FFDs of AD Leo obtained in this research and the previous study are basically consistent, which suggests that the magnetic activity of this star has not significantly changed compared to that decades ago. Comparing with the average FFD of M-type stars, AD Leo's FFD is twice higher, indicating that its magnetic activity is more active than that of the average level of the M-type. Based on TESS light curve, AD Leo's rotation period is calculated as 2.21${+0.01 \choose -0.01}$ day , supporting the result given in previous research. During the decay phase of the most energetic flare from TESS, we identified QPPs and determined a 26.5-min oscillation period, which is currently the longest period for AD Leo, suggesting that long periodic physical process existed during flare of this star

Ligustrazine Injection for Chronic Pulmonary Heart Disease: A Systematic Review and Meta-Analysis

Objective. This study was intended to evaluate the efficacy and safety of ligustrazine injection for chronic pulmonary heart disease (CPHD). Method. Randomized controlled trials (RCTs) of clinical therapeutic studies on CPHD when using ligustrazine injection were included. Searches were applied to the following electronic databases: the PubMed, the Cochrane Library, EMBASE, CBM, and AMED. No language restriction was used. All trials included were analyzed according to the criteria of the Cochrane Handbook. Review Manager 5.0 software was used for data analysis. Result. 34 RCTs with low methodological quality were included. Compared to conventional medicine treatment alone, ligustrazine injection plus conventional medicine treatment showed improvement in New York Heart Association classification of clinical status (Odds ratio 0.22; 95% CI 0.17 to 0.28) and depression of pulmonary artery hypertension (weighted mean difference −4.77; 95% CI −5.85 to −3.68). Three studies had reported adverse events. No serious adverse effects were reported. Conclusion. While there is some evidence that suggests potential effectiveness of ligustrazine injection for CPHD, the results were limited by the methodological flaws of the studies. High quality studies are needed to provide clear evidence for the future use of ligustrazine injection

The significance of Notch ligand expression in the peripheral blood of children with hand, foot and mouth disease (HFMD)

BACKGROUND: Hand, foot and mouth disease (HFMD), a virus-induced infectious disease that usually affects infants and children, has an increased incidence in China in recent years. This study attempted to investigate the role of the Notch signaling pathway in the pathogenesis of HFMD. METHODS: Eighty-two children diagnosed with HFMD were enrolled into this study. The HFMD group was further divided into the uncomplicated HFMD and HFMD with encephalitis groups. The control group included 40 children who underwent elective surgery for treatment of inguinal hernias. RESULTS: Children with HFMD displayed significantly reduced CD3+, CD3+CD4+ and CD3+CD8+ cell subsets, but substantially enhanced CD3−CD19+ cell subset (p < 0.05 versus control subjects). The expression levels of Notch ligands Dll1 and Dll4 in the peripheral blood of the HFMD group were significantly higher than those in the control group (p < 0.05). There were statistically significant differences in CD3+, CD3+CD4+ and CD3−CD19+ cell subsets, but not in Notch ligand expression, between the uncomplicated HFMD and HFMD with encephalitis groups. Dll4 expression in HFMD subjects correlated negatively with the CD3+ and CD3+CD8+ cell subsets (p < 0.05), but positively with the CD3−CD19+ cell subset (p < 0.05). Furthermore, Dll4 expression in HFMD with encephalitis subjects correlated positively with total white blood cell (WBC) counts and total protein contents in cerebrospinal fluid (CSF) (p < 0.05). CONCLUSIONS: The Notch ligand Dll4 exhibits a strong correlation with the CD3+, CD3+CD8+ and CD3−CD19+ cell subsets in children with HFMD, indicating that the Notch signaling may be involved in the development of HFMD by affecting the number and status of peripheral lymphocytes

Anti-aging effect of hydrocolloid on tartary buckwheat parfaith

The effects of mono-hydrophilic colloid(xanthan gum,guar gum,sodium alginate,hydroxypropyl methylcellulose and carrageenan) on the anti-aging of tartary buckwheat parfait were studied with sensory evaluation and hardness as indexes,and three kinds of hydrophilic colloid with better anti-aging effect were screened out.Based on this,the optimal anti-aging agent of tartary buckwheat parfait was determined by response surface analysis method.The results showed that the optimal anti-aging agent formula was 0.13%of xanthan gum,0.17% of sodium alginate and 0.24% of carrageenan(calculated bytotal slurryweight).The storage time of tartary buckwheat parfait with compound hydrophilic colloids was prolonged by 2 times(14 days)of that without hydrocolloid the at-4 ℃

The Viral TRAF Protein (ORF111L) from Infectious Spleen and Kidney Necrosis Virus Interacts with TRADD and Induces Caspase 8-mediated Apoptosis

Infectious spleen and kidney necrosis virus (ISKNV) is the type species of the Megalocytivirus genus of the Iridoviridae family. It causes a serious and potentially pandemic disease in wild and cultured fishes. ISKNV infection induces evident apoptosis in mandarin fish (Siniperca chuatsi) and zebrafish (Danio renio). However, the mechanism is still unknown. After a genome-wide bioinformatics analysis of ISKNV-encoded proteins, the ISKNV open reading frame 111L (ORF111L) shows a high similarity to the tumour necrosis factor receptor-associated factor (TRAF) encoded by fish, mice and mammals, which is essential for apoptotic signal transduction. Moreover, ORF111L was verified to directly interact with the zebrafish TNF receptor type 1 associated death domain protein (TRADD). A recombinant plasmid containing the DNA sequence of ORF111L was constructed and microinjected into zebrafish embryos at the 1–2 cell stage to investigate its biological function in vivo. ORF111L overexpression in the embryos resulted in increased apoptosis. ORF111L-induced apoptosis was clearly associated with significant caspase 8 upregulation and activation. The knockdown of zebrafish caspase 8 expression effectively blocked the apoptosis induced by ORF111L overexpression. Significantly, ORF111L overexpression resulted in much stronger effect on caspase 8 and caspase 3 upregulation compared to zebrafish TRAF2. This is the first report of a viral protein similar to TRAF that interacts with TRADD and induces caspase 8-mediated apoptosis, which may provide novel insights into the pathogenesis of ISKNV infection

Progress in key technologies for traceability of rice industry chain

As one of the main food crops in the world, the rice quality and safety situation is not optimistic, the development of rice traceability system has become a hot topic at home and abroad. This paper summarizes the research status of rice traceability technology from two aspects including the origin diagnosis technology (such as: physical index fingerprint technology, stable isotope technology, multi-element analysis technology, near-infrared spectroscopy technology) and the traceability system technology (such as: physical identification technology, information coding technology, information transmission technology). Based on this analysis, the development trend of rice traceability system was analyzed, and new technologies will continue to be applied to the traceability system