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The effect of increasing the bonding pressure from 10 to 20 MPa (5 MPa interval) at 1050°C for 60 minutes on the diffusion bonded joint of reduced activation ferritic/martensitic (RAFM) steel was investigated. The results indicate that the quality of the bond improves accordingly with increasing bonding pressure. The oxide layer at the bonding interface underwent an evolution process from continuous to discontinuous and ultimately disappeared with the increase of bonding pressure. The optimal joint was achieved in this work at the pressure of 20 MPa. Considering the research of reliability of joints in engineering applications, the optimum joint was subjected to post-bonding heat treatment (PBHT) of 750°C for 90 minutes. The diffusion bonded sample subjected to PBHT exibits microstructural features and tensile properties similar to those of the base metal. It is noteworthy that the tensile fracture does not occur at the bonding interface, but in the base metal far away from the interface. This work can provide a feasible method for the removal of oxides at the diffusion bonding interface of RAFM steel and also contribute to the establishment and optimization of diffusion bonding processes, thereby improving the quality of the diffusion bonding joint.

Both tea polyphenols (TP) and Lactobacillus rhamnosus have been shown to alleviate obesity, and regulate lipid metabolism. However, the combined effects and their underlying mechanisms of action remain elusive. In the present work, the effects of TP, Lactobacillus rhamnosus R5 (R5), and TP+R5 on blood lipids and the gut microbiota of mice fed with a high-fat diet were compared. Results showed that the combination of TP and R5 effectively increased the serum levels of high-density lipoprotein cholesterol (HDL-C), and decreased total cholesterol (TC) levels, low-density lipoprotein cholesterol (LDL-C) levels, and the atherosclerosis index (AI) in mice fed with a high-fat diet. The combination treatment resulted in a modification of the structure of the gut microbiota in mice, as evidenced by a decrease in the F/B ratio, and an increase in the abundance of beneficial genera, such as Akkermansia muciniphila, Faecalibaculum rodentium, and Ruminococcus_uncultured bacterium. Additionally, the contents of SCFAs (acetic, propionic, and butyric acids) in faeces also increased. These could provide new ideas for anti-obesity methods, and a theoretical basis for the development of foods combining probiotics and tea polyphenols. [ABSTRACT FROM AUTHOR]

To understand the jet flow characteristics of turbofan separate exhaust system, a parametric design method based on the initial Class Shape Transformation function was developed. HBPR and UHBPR turbofan separate exhaust systems were designed. Furthermore, the jet flow characteristics of the HBPR turbofan exhaust system under take-off condition with zero angle of attack were studied based on numerical simulation. The jet flow characteristics of the HBPR and UHBPR turbofan exhaust system under take-off condition with high angle of attack were also simulated. The effects of angle of attack and bypass ratio on the jet flow characteristics were investigated and the related flow mechanisms were analyzed. Results show that the axisymmetric plumes of the HBPR turbofan exhaust system are distributed around the engine axis under take-off condition with zero angle of attack. With the plug wake as the center, the core flow, the fan/core shear layer, the fan flow, the fan/free stream shear layer and the free stream are wrapped around the plug wake from inside out. Vortexes appear in the lee area at the back of the cowl and jet flow under take-off condition with high angle of attack. These vortexes cause cross sectional secondary flow and expose the highvelocity core flow to the low-velocity free stream. The contact area and velocity gradient in the mixing region among the free stream, fan flow and core flow increase. Therefore, the mixture among jet flow and free stream strengthens. So the high-velocity region, the high-vorticity region, and the high turbulence kinetic energy region shorten by 55.1%, 47.7% and 50.9% respectively. The vorticity values and turbulence kinetic energy level peak on the upper side of the exhaust plumes increase by about 30% and 87% respectively. Relative to these parameters from the HBPR turbofan exhaust system, the jet velocity peak value of UHBPR turbofan decreases by 5.5% under take-off condition with high angle of attack. The vorticity values and turbulence kinetic energy level reduce due to decreased velocity gradient in shear layers downstream of the nozzle exit plane. The turbulence kinetic energy level peak on the upper side of the exhaust plumes decreases by 29.3%. The reasons are that the contact area between high-velocity core flow and the free stream decreases due to thicker fan flow and the velocity gradient in the core flow and free stream mixing region decreases because of the lower core flow velocity. [ABSTRACT FROM AUTHOR]

In order to understand the coupled effect of the nacelle and exhaust system and to improve their overall performance, we studied the aerodynamic performance and the flow characteristics of the high bypass ratio turbofan nacelle and exhaust system by numerical simulation. The geometric parameters of a nacelle and exhaust system (e.g., the contraction ratio of the cowl afterbody and the fan nozzle exit angle) were investigated to evaluate their influence on the overall performance of the nacelle and exhaust system. The related flow mechanism was explored as well. The results show that the flow field of the nacelle and exhaust system under the mid-cruise condition exhibits characteristics of transonic flow. A stagnation zone exits at the nacelle lip and there is a velocity peak at the nacelle forebody. There exist a number of complex flow phenomena (such as shockwave, expansion wave, shear flow and shock wave-boundary layer interaction) in the downstream of the fan nozzle exit plane. The magnitude of the fan nozzle thrust or the intake ram drag is much higher than that of the additional drag, the nacelle drag or the core nozzle thrust. And for the nacelle drag, the friction drag of the cowl is in the same order of magnitude as the pressure drag of the cowl, the core cowl and the plug. But it is much larger than the friction drag of the core cowl and the plug. The effective thrust increases by 4.7% as the contraction ratio of the cowl afterbody increases; and it increases by 2.4% as the fan nozzle exit angle increases. The expansion degree of the fanjet flow, the shock wave strength and location, and the existence of the flow separation or second shock wave are influenced by the contraction ratio of the cowl afterbody and the fan nozzle exit angle. These phenomena have effects on the pressure distribution of the core cowl and the surrounding fanjet flow velocity, and hence they further affect the nacelle drag. The increase in the fan nozzle exit angle can noticeably reduce the thrust of the fan nozzle. [ABSTRACT FROM AUTHOR]

This article discusses a case of lupus nephritis with posterior reversible encephalopathy syndrome (PRES) as the first manifestation. PRES is an acute neurological disorder characterized by various symptoms, including seizures and visual disturbances. Common triggers of PRES include lupus nephritis, autoimmune disease, and hypertension. The patient in this case experienced a sudden seizure and was diagnosed with stage IV lupus nephritis. Treatment with medications and supportive therapies resulted in symptom relief and renal remission. The article emphasizes the importance of early identification and treatment of PRES to prevent complications. [Extracted from the article]

Ion-exchanged Mach-Zehnder interferometers are produced in glass. The effect of fabrication parameters on their optical response in relation to their constituent components is investigated.