Sulphur abundances in disk stars: A correlation with silicon

We have performed new determinations of sulphur and silicon abundances for a sample of 26 disk stars based on high-resolution, high signal-to-noise spectra. The results indicate a solar [S/Fe] for [Fe/H] > −0.3, below which [S/Fe] increases to ~0.25 dex at [Fe/H] = −1.0. We find that there is a good correlation between [S/H] and [Si/H], indicating the same nucleosynthetic origin of the two elements. It seems that the ratio of sulphur to silicon does not depend on metallicity for [Fe/H] > −1.0. The implications of these results on models for the nucleosynthesis of a-capture elements and the chemical evolution of the Galaxy are discussed. Based on observations carried out at National Astronomical Observatories (Xinglong, PR China)

Modelling the engineering behaviour of fibrous peat formed due to rapid anthropogenic terrestrialization in Hangzhou, China

This is an accepted manuscript of an article published by Elsevier in Engineering Geology on 21/10/2016, available online: https://doi.org/10.1016/j.enggeo.2016.10.009 The accepted version of the publication may differ from the final published version.Peat is a very variable but normally weak material. While engineering failures involving peat are common, the full diversity of engineering behaviours exhibited by peat has not been well classified due to its large range of possible compositions. This paper presents the behaviour of a fibrous peat which is a fill (made ground) originating from the most recent dredging of the West Lake, a site of cultural and historic importance in China. Given its relatively unique mechanism of deposition, the distinctive characteristics of this peat are presented in comparison to other peats reported in the literature highlighting its unique engineering behaviour. A laboratory study carried out on the peat at Jiangyangfan Eco-park, located in Hangzhou, China identifies that it has its special aspects when compared to other peats. The shearing behaviour of peat can be described using the framework of critical state theory. The most prominent characteristic of the West Lake Peat is that its undrained stress path bends towards the left at the very beginning of shearing which indicates that plastic deformation occurs at very small stress ratios. A constitutive model based on critical state theory for predicting the undrained shear behaviour of this type of peat from low stress to critical state levels is presented. This model also includes several elements of peat behaviour previously reported and it may therefore be applied to a wider range of peat soils

Antibacterial effect of orange Monascus pigment against Staphylococcus aureus

The objective of this work was to research the antibacterial effects of orange pigment, which was separated from Monascus pigments, against Staphylococcus aureus. The increase of the diameter of inhibition zone treated with orange pigment indicated that orange pigment had remarkable antibacterial activities against S. aureus. Orange pigment (10 mg ml−1) had a strong destructive effect on the membrane and structure of S. aureus by the analysis of scanning electron microscopy as well as transmission electron microscopy. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) further demonstrated that the cell membrane was seriously damaged by orange pigment, which resulted in the leakage of protein from S. aureus cells. A significant decrease in the synthesis of DNA was also seen in S. aureus cells exposed to 10 mg ml−1 orange pigment. All in all, orange pigment showed excellent antibacterial effects against S. aureus

Quantification of the boron speciation in alkali borosilicate glasses by electron energy loss spectroscopy

Transmission electron microscopy and related analytical techniques have been widely used to study the microstructure of different materials. However, few research works have been performed in the field of glasses, possibly due to the electron-beam irradiation damage. In this paper, we have developed a method based on electron energy loss spectroscopy (EELS) data acquisition and analyses, which enables determination of the boron speciation in a series of ternary alkali borosilicate glasses with constant molar ratios. A script for the fast acquisition of EELS has been designed, from which the fraction of BO(4) tetrahedra can be obtained by fitting the experimental data with linear combinations of the reference spectra. The BO(4) fractions (N(4)) obtained by EELS are consistent with those from (11)B MAS NMR spectra, suggesting that EELS can be an alternative and convenient way to determine the N(4) fraction in glasses. In addition, the boron speciation of a CeO(2) doped potassium borosilicate glass has been analyzed by using the time-resolved EELS spectra. The results clearly demonstrate that the BO(4) to BO(3) transformation induced by the electron beam irradiation can be efficiently suppressed by doping CeO(2) to the borosilicate glasses

Superconductivity in MgB_2 doped with Ti and C

Measurements of the superconducting upper critical field, H_{c2}, and critical current density, J_c, have been carried out for MgB_2 doped with Ti and/or C in order to explore the problems encountered if these dopants are used to enhance the superconducting performance. Carbon replaces boron in the MgB_2 lattice and apparently shortens the electronic mean free path thereby raising H_c2. Titanium forms precipitates of either TiB or TiB_2 that enhance the flux pinning and raise J_c. Most of these precipitates are intra-granular in the MgB_2 phase. If approximately 0.5% Ti and approximately 2% C are co-deposited with B to form doped boron fibers and these fibers are in turn reacted in Mg vapor to form MgB_2, the resulting superconductor has H_{c2}(T=0) ~ 25 T and J_c ~ 10,000 A/cm**2 at 5 K and 2.2 T.Comment: 11 pages, 10 figure

Experiments and Simulation on Mannesmann Piercing Process in the Drill Steel Manufacture

Steel drill rods are employed in the mining industry to drill blast holes in rock, for them a high-quality metal surface and accurate geometrical parameters are essential. Drill steel is a special material exclusively designed for drill rods. To estimate the microstructure and dimensional stability of drill steel, a rigid plastic finite element method (FEM) was applied in examining the Mannesmann piercing in the drill steel manufacture. The three-dimensional thermal-force coupling FEM models were computer-generated with different plug positions.Стальные буровые штанги используются в горной промышленности для бурения взрывных скважин в породе, для них высокое качество металлической поверхности и точные геометрические параметры являются непременным условием. Буровая сталь особый материал, разработанный специально для буровых штанг. Для оценки микроструктуры и устойчивости размеров буровой стали был использован метод конечных элементов для жесткопластического анализа прошивки Маннесмана в производстве буровой стали. Трехмерные конечноэлементные модели термосилового взаимодействия разрабатывали на компьютере, используя различные положения оправки

Performance assessment and microbial diversity of two pilot scale multi-stage sub-surface flow constructed wetland systems

This study assessed the performance and diversity of microbial communities in multi-stage sub-surface flow constructed wetland systems (CWs). Our aim was to assess the impact of configuration on treatment performance and microbial diversity in the systems. Results indicate that at loading rates up to 100g-BOD5/m2.day, similar treatment performances can be achieved using either a 3 or 4 stage configuration. In the case of phosphorus (P), the impact of configuration was less obvious and a minimum of 80% P removal can be expected for loadings up to 10g–P/m2.day based on the performance results obtained within the first 16 months of operation. Microbial analysis showed an increased bacterial diversity in stage four compared to the first stage. These results indicate that the design and configuration of multi-stage constructed wetland systems may have an impact on the treatment performance and the composition of the microbial community in the systems, and such knowledge can be used to improve their design and performance

Recognizing basal cell carcinoma on smartphone‐captured digital histopathology images with a deep neural network

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154530/1/bjd18026.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154530/2/bjd18026_am.pd

A batch-service queueing model with a discrete batch Markovian arrival process

Queueing systems with batch service have been investigated extensively during the past decades. However, nearly all the studied models share the common feature that an uncorrelated arrival process is considered, which is unrealistic in several real-life situations. In this paper, we study a discrete-time queueing model, with a server that only initiates service when the amount of customers in system (system content) reaches or exceeds a threshold. Correlation is taken into account by assuming a discrete batch Markovian arrival process (D-BMAP), i.e. the distribution of the number of customer arrivals per slot depends on a background state which is determined by a first-order Markov chain. We deduce the probability generating function of the system content at random slot marks and we examine the influence of correlation in the arrival process on the behavior of the system. We show that correlation merely has a small impact on the threshold that minimizes the mean system content. In addition, we demonstrate that correlation might have a significant influence on the system content and therefore has to be included in the model

Determination of oxygen stoichiometry in the mixed-valent manganites

The possible redox (oxidation reduction) chemical methods for precisely determining the oxygen content in the perovskite manganites including hole-doped La1-xCaxMnOy and electron-doped La1-xTexMnOy compounds are described. For manganites annealed at different temperatures, the oxygen content of the samples was determined by a redox back titration in which the powder samples taken in a quartz crucible were dissolved in (1+1) sulfuric acid containing an excess of sodium oxalate, and the excess sodium oxalate was titrated with permanganate standard solution. The results indicate that the method is effective and highly reproducible. Moreover, the variation of oxygen content is also reflected in significantly affecting the electrical transport property of the samples, which is mainly considered to be closely related to introduce oxygen vacancies in the Mn-O-Mn network.Comment: 13 pages, 1 figure. J. Magn. Magn .Mater (accepted