Solid oxide fuel cell composite cathodes based on perovskite and fluorite structures

This work presents the results related to the functionally graded fluorite (F)-perovskite (P) nanocomposite cathodes for IT SOFC. Nanocrystalline fluorites (GDC, ScCeSZ) and perovskites (LSrMn, LSrFNi) were synthesized by Pechini method. Nanocomposites were prepared by the ultrasonic dispersion of F and P powders in isopropanol with addition of polyvinyl butyral. Different techniques for deposition and sintering of functionally graded cathode materials were applied including traditional approaches as well as original methods, such as radiation-thermal sintering under electron beam or microwave radiation. Morphology, microstructure and elemental composition of nanocomposites was characterized by XRD and HRTEM/SEM with EDX. Even for dense composites, the sizes of perovskite and fluorite domains remain in the nanorange providing developed P-F interfaces. Oxygen isotope heteroexchange and conductivity/weight relaxation studies demonstrated that these interfaces provide a path for fast oxygen diffusion. The redistribution of the elements between P and F phases in nanocomposites occurs without formation of insulating zirconate phases. Button-size fuel cells with nanocomposite functionally graded cathodes, thin YSZ layers and anode Ni/YSZ cermet (either bulk or supported on Ni-Al foam substrates) were manufactured. For optimized composition and functionally graded design of P-F nanocomposite cathodes, a stable performance in the intermediate temperature range with maximum power density up to 0.5 W cm⁻² at 700 °C in wet H₂/air feeds was demonstrated.     

Role of acidic sphingomyelinase in thymol‐mediated dendritic cell death

Scope : Thymol is a component of several plants with antimicrobial activity. Little is known about the effects of thymol on immune cells of the host. This study addressed the effects of thymol on dendritic cells (DCs), regulators of innate and adaptive immunity. Methods and results : Immunohistochemistry, Western blotting and fluorescence‐activated cell sorting analysis were performed in bone marrow‐derived DCs either from wild‐type mice or from mice lacking acid sphingomyelinase (ASM^?/?) treated and untreated for 24 h with thymol (2–100 μg/mL). Thymol treatment resulted in activation of ASM, stimulation of ceramide formation, downregulation of anti‐apoptotic Bcl‐2 and Bcl‐xL proteins, activation of caspase 3 and caspase 8, DNA fragmentation as well as cell membrane scrambling. The effects were dependent on the presence of ASM and were lacking in ASM^?/? mice or in wild‐type DCs treated with sphingomyelinase inhibitor amitriptyline. Conclusion : Thymol triggers suicidal DC death, an effect mediated by and requiring activation of ASM.     

Piecewise approximate analytical solutions for a Jeffcott rotor with a snubber ring

In the paper two approximate analytical methods for calculating nonlinear dynamic responses of an idealised model of a rotor system are devised in order to obtain robust analytical solutions, and consequently speed up the computations maintaining high computational accuracy. The physical model, which is similar to a Jeffcott rotor, assumes a situation where gyroscopic forces can be neglected and concentrates on the dynamic responses caused by interactions between a whirling rotor and a massless snubber ring, which has much higher stiffness than the rotor. The system is modelled by two second-order differential equations, which are linear for non-contact and strongly nonlinear for contact scenarios. The first and the simpler method has been named one point approximation (1PA) and uses only one point in the first-order Taylor expansion of the nonlinear term. It is suitable for soft impacts and gives a reasonable prediction of responses ranging from period one to period four motion. The second and more accurate method of multiple point approximation (MPA) expands the nonlinear term many times when the rotor and the snubber ring are in contact and it can even be used for calculating chaotic responses. The methods are evaluated by a comparison with direct numerical integration showing an excellent level of accuracy.     

Internal migration of scientists in Russia and the USA: the case of physicists

To assess endocrinologic and metabolic research productivity in East Asia (i.e., China, Japan, and South Korea) and correlations between socioeconomic factors and endocrinologic and metabolic research productivity. Articles (except editorials, conference abstracts, letters, news, and corrections) published in 134 endocrinology and metabolism journals in 2005–2014 were screened with the Web of Science database. Total and annual numbers of articles, study designs, impact factors, citations, and articles in high-impact-factor journals were determined for China, Japan, and South Korea. Annual numbers of articles were related to socioeconomic factors for each country. In 2005–2014, there were 144,660 articles from East Asia published in endocrinology and metabolism journals: 10,190, 9470, and 3124 from Japan, China, and South Korea, respectively. Japan published the most randomized controlled trials, followed by China and South Korea, respectively. China had the most articles in high-impact-factor journals, followed by Japan and South Korea, respectively. South Korea had the highest average impact factor and number of citations. During the period studied, annual numbers of articles from China and South Korea increased remarkably (P < 0.05) but remained stable for Japan. Annual numbers of articles from China and South Korea were positively correlated with gross domestic product and expenditure on health care (P < 0.05). The increase in endocrinology and metabolism articles during 2005–2014 in China and South Korea was associated with improved socioeconomic conditions. China has made progress in scientific publication in the past decade; however, there is still room for improvement.     

Residual stresses in the graded interlayer between W and CuCrZr alloy

Journal of Materials Science - One of the big challenges for realizing future nuclear fusion reactors is the development of materials able to withstand the high thermal loads and particle fluxes...     

Glass–Ceramic Composites with Strontium Hexaferrite Ultrafine Particles in the SrO–Fe2O3–B2O3–SiO2 System

Glass samples with nominal compositions SrFe₁₂O₁₉+(12− n )SrB₂O₄+nSrSiO₃, n =3, 6, 9 were prepared by rapid quenching of the melt. Processes of glass devitrification were studied. The samples were annealed at temperatures of 600–900°C, and the resulting glass–ceramics was characterized by XRD, SEM, EDX, and magnetic measurements. SrFe₁₂O₁₉ crystallizes above 700°C and forms nano- and submicron platelet particles with the aspect ratio depending on the thermal treatment conditions. The glass–ceramic samples annealed at 900°C show coercive force values in the range of 422–455 kA/m.     

西九文化区

正OMA发展西九文化区,必须面对一项挑战:将一个盛载政府极大抱负,以及持分者多元利益的超大型多用途项目,转化成一个既有趣又严肃、既有规划又允许即兴、既中国化又国际化的文化区。这个文化区规模庞大,但不失亲密融洽的感觉;富地标性,但十分谦和;容易理解,却能带来惊喜。为避免造成过分冲击,OMA采纳了一种每个香港市民都熟悉的建筑类型作为方案的发展