The measurement of the diffusion coefficient and the sorption isotherm of water in paint films

An experimental technique together with a numerical model is proposed with which the diffusion coefficient and the sorption isotherm of water in paint can be measured. Inside a closed vessel, paint films are on stainless-steel plates. Water is present as water vapour in the air and in the paint. After blowing dry or wet air through the vessel for some time, the situation moves to a new equilibrium. The relative humidity of the air inside the vessel is measured as a function of time. From fitting the theoretical/numerical model against the experimental values, follow the diffusion coefficient and the sorption isotherm of water in the paint. The results show large scattering. When the independently measured sorption isotherm is used as an input parameter in the model, the fitting procedure gives much smaller scattering for the diffusion coefficient.     

生物聚合物的创新应用

描述了生物聚合物的创新应用.探索了两种趋势的原因.首先,最近三年中,原油价格猛涨,各种衍生物的价格也随之上涨,促使人们寻找其他可能的原料.其次,欧洲农业处于重大变革的前夜,环境法律的实施,向世界经济的开放以及补贴的减少,促使农业寻找新的市场.玉米和糖用甜菜可能是未来的出路.     

Thermoplastic vulcanizates obtained by reaction-induced phase separation: Interplay between phase separation dynamics,final morphology and mechanical properties

Reaction-induced phase separation (RIPS) of miscible blends of poly(?-caprolactone) (PCL) and an epoxy resin based on poly(propylene oxide) (PPO) was used to prepare thermoplastic vulcanizates (TPVs) with fine rubber dispersions. Scanning electron microscopy (SEM) confirmed the formation of cross-linked rubber particles dispersed in the thermoplastic matrix at PCL contents ≥20 wt%. The morphology development during phase separation was studied by optical microscopy (OM) and time-resolved small-angle light scattering (SALS). It was shown that higher curing temperatures lead to a decrease in rubber particle size, but at the same time lead to an increase in the extent of particle connectivity. In some cases, gelation of the PPO-rich phase limits full structure development, which leads to extensive connectivity between the dispersed rubber particles and a strong deterioration in tensile properties.     

Soccer schedules in Europe: an overview

In this paper, we give an overview of the competition formats and the schedules used in 25 European soccer competitions for the season 2008?C2009. We discuss how competitions decide the league champion, qualification for European tournaments, and relegation. Following Griggs and Rosa (Bull. ICA 18:65?C68, 1996), we examine the popularity of the so-called canonical schedule. We investigate the presence of a number of properties related to successive home or successive away matches (breaks) and of symmetry between the various parts of the competition. We introduce the concept of ranking-balancedness, which is particularly useful to decide whether a fair ranking can be made. We also determine how the schedules manage the carry-over effect. We conclude by observing that there is quite some diversity in European soccer schedules, and that current schedules leave room for further optimizing.     

Workload assignment for global real-time scheduling on unrelated clustered platforms

Real-Time Systems - Heterogeneous MPSoCs are being used more and more, from cellphones to critical embedded systems. Most of those systems offer heterogeneous sets of identical cores. In this...     

Stability of sitting postures: the influence of degrees of freedom

Observational studies of sitting have shown that, during spontaneous sitting, people adopt a variety of postures. Various researchers have formulated theories to explain why people adopt their sitting postures. Branton (1969) hypothesized that there is continual need for postural stability while sitting. Dempster (1955) stated that additional stability could be obtained through temporarily closing chains of body segments, or, in other words, through decreasing the number of degrees of freedom of the body. The present study elaborates on Dempster's theory. The aim of this study was to determine the influence of the degrees of freedom of the body on postural stability in sitting postures. For 21 different sitting postures, the total number of degrees of freedom was determined. Postural sway, a measure for postural stability, was determined using a 3D motion and position measurement system with ten healthy subjects. This study shows that the mean path length at the level of the second thoracic vertebra (PL0.05), a measure derived from postural sway, increases significantly (p < 0.0001) with an increase of the number of degrees of freedom of the body (DoFB). Closer examination of the data showed that a model taking into account only the degrees of freedom of the lumbar and thoracic spine and pelvis seems to be a better predictor of postural sway than the total number of degrees of freedom of the body.     

Measuring Single-Crystal Diffuse Neutron Scattering on the Wombat High-Intensity Powder Diffractometer

Single-crystal diffuse scattering was collected on the Wombat high-intensity powder diffractometer at the OPAL reactor at the Bragg Institute. The difficulty in measuring diffuse scattering comes from its relatively low intensity compared to the Bragg peaks, a factor of 10³10^{3} to 10⁴10^{4} smaller. Wombat allows collection of diffuse scattering due to its high intensity and large two-dimensional detector. Diffuse scattering data from yttria-stabilized cubic zirconia (YCSZ, Y₂O₃\hbox{Y}_2\hbox{O}_3 stabilized ZrO₂\hbox{ZrO}_2) and PbZn_1/3Nb_2/3O₃\hbox{PbZn}_{1/3}\hbox{Nb}_{2/3}\hbox{O}_3 (PZN) were successfully collected, the latter at a range of temperatures. The data were processed, normalized, and background subtracted to reconstruct flat reciprocal space sections with a minimum of artifacts. The strategies used to tackle the collection of neutron diffuse scattering and the way in which they are implemented will be discussed. The results show that the neutron powder diffractometer with a continuous detector is capable of collecting high-quality diffuse scattering data.     

Assessing Local Structure in PbZn1/3Nb2/3O3 Using Diffuse Scattering and Reverse Monte Carlo Refinement

We use an extensive X-ray diffuse scattering dataset collected from the relaxor ferroelectric PbZn_1/3Nb_2/3O₃ to study the feasibility of refining a nanoscale structure with the reverse Monte Carlo method. Six integer and non-integer reciprocal sections are used with a total number of nearly 10⁵ symmetry-independent data points. Very good agreement between observed and calculated diffuse scattering patterns is achieved with rather subtle diffuse intensity modulations being satisfactorily reproduced. The correlations within the refined local structure are related to the possible physical mechanisms behind them. We discuss the ambiguity of the obtained results and feasible constraining schemes.