Elaboration and properties of novel biobased nanocomposites with halloysite nanotubes and thermoplastic polyurethane from dimerized fatty acids

Nanocomposites of biobased thermoplastic polyurethane (TPU) from dimer fatty acids and halloysite nanotubes (HNT) were elaborated by different melt processing routes such as direct mixing (1 step process) and masterbatch/dilution (2 steps process), at different temperatures (150 and 180 °C). Rheological and transmission electron microscopy (TEM) analyses indicated that the HNT distribution and dispersion were dependent on the processing conditions: the 2 steps process produced well dispersed nanocomposites and the masterbatch dilution at 180 °C improved the HNT distribution through the TPU. Consequently, a high reinforcement was achieved, with a 40% increase in the elastic modulus and 8 °C increase in the relaxation temperature related to the glass transition of the TPU soft segments. Furthermore, a percolated network was attained, even if a large extent of HNT breaking was observed during processing, suggesting that a synergistic effect between the HNT particles and the TPU's hard segments in the molten state occurred. Thus, HNT nanotubes can be seen as highly reinforcing nanofillers when good dispersion and distribution are achieved through the polymeric matrix.     

Finite sample properties of Moran's I test for spatial autocorrelation in tobit models

In this note, we investigate the finite‐sample properties of Moran's I test statistic for spatial autocorrelation in tobit models suggested by Kelejian and Prucha. We fill a void in the theoretical literature by investigating the finite sample properties of this test statistic in a series of Monte Carlo simulations, using data sets ranging from 49 to 15,625 observations. We find that the test is unbiased, has considerable power and approximates the asymptotic normal distribution even for medium‐sized sample sizes, empirically confirming the theoretical results of Kelejian and Prucha. However, some caution is needed, since the statistic turns out to be sensitive to misspecification in the form of heteroscedasticity. In such instances the test over‐rejects the null hypothesis, mistaking heteroscedasticity for spatial autocorrelation.     

Performance characterization of a small-capacity thermoacoustic cooler for air-conditioning applications

The performance of a working prototype, operated with and without water flow through the heat exchangers, was measured and found to be in reasonably close agreement to predictions from a simulation code, DELTAE, based on linear thermoacoustic theory. Further analysis and DELTAE simulations showed that the coefficient of performance may be significantly reduced when the stack temperature profile becomes non-linear, i.e. when the system is operated for a temperature span smaller than the optimal value for a given stack length. Guidelines to avoid this condition are provided.     

Consumer perception of boar meat as affected by labelling information,malodorous compounds and sensitivity to androstenone

This study aimed to assess the influence of two label conditions on the acceptance of boar meat. A central location test was conducted with 145 consumers each assessing 4 pieces of pork loin.     

High‐resolution solid‐state NMR investigation of the filler–rubber interaction: 2. High‐speed [1H] magic‐angle spinning NMR spectroscopy in carbon‐black‐filled polybutadiene

This work investigates the behaviour of elastomeric chains (polybutadienes of identical molecular weight but different microstructures) in the close vicinity of carbon black surfaces in order to attain a better understanding of the structure and properties of interphases. Elastomer–filler interactions are assessed through the study of the thermal properties and NMR relaxation characteristics of the corresponding materials. Three series of samples were compared: pure polymers, raw polymer–filler blends (filler loading ratio: 50 phr) and solvent‐extracted blends (so as to get rid of any polymer which is not under the influence of the solid surface). While differential scanning calorimetry points to the existence of an elastomer fraction which is not detected as undergoing the glass transition, ie is strongly immobilized, [¹H] high‐resolution high‐speed magic‐angle spinning solid‐state NMR provides information on the effect exerted by polymer–filler interactions on the mobility of the various constitutive species of the macromolecular backbone. A systematic study of the evolution of the spectral lines yielded by the samples indicates that 1,2‐polybutadiene moieties have a particular affinity towards the carbon black surface which suggests the occurrence of specific interactions at the elastomer–filler interface. © 2001 Society of Chemical Industry     

EVS助力北京奥运会赛事转播——EVS设备在BOB及CCTV的成功应用

一奥运相关背景与数据 2008年北京夏季奥运会设有28项比赛和302枚金牌，分别在37个比赛场馆举行。参加本次奥运会的运动员共有10708名。奥运会设有国际广播中心（IBC），总面积为9万平方米。参与本届奥运会转播工作的工作人员共有16000人，其中BOB的工作人员有4000人。在奥运期间．BOB一共制作了4000小时的电视节目。     

Cluster-grouping: from subgroup discovery to clustering

We introduce the problem of cluster-grouping and show that it can be considered a subtask in several important data mining tasks, such as subgroup discovery, mining correlated patterns, clustering and classification. The algorithm CG for solving cluster-grouping problems is then introduced, and it is incorporated as a component in several existing and novel algorithms for tackling subgroup discovery, clustering and classification. The resulting systems are empirically compared to state-of-the-art systems such as CN2, CBA, Ripper, Autoclass and CobWeb. The results indicate that the CG algorithm can be useful as a generic local pattern mining component in a wide variety of data mining and machine learning algorithms.     

Instability during cohesive zone growth

Tensile microcracking of quasi-brittle materials is studied by means of micromechanics, based on (i) an elasto-damaging cohesive zone model accounting for cohesive softening and (ii) a dilute distribution of non-interacting microcracks of uniform orientation and size. Considering virgin microcracks (initially without cohesive zones), macroscopic tensile load increase results in growth of cohesive zones ahead of stationary (non-propagating) cracks and, subsequently, in crack propagation which, notably, will be encountered before the cohesive zones are fully developed i.e. onset of instable cohesive zone growth will be encountered at a load level (i) at which tractions are still transmitted across the inner edges of the cohesive zones and (ii) at which the separation at the inner edges of the cohesive zones is smaller than its critical value. Focusing on onset of instable cohesive zone growth, the chosen approach allows for accessing quantities characterizing the stability limit (e.g., the intensity of the macroscopic loading and the opening at the inner edges of the cohesive zones), without raising the need for non-linear Finite Element analyses. It is shown that the tensile macrostrength of materials containing virgin microcracks is larger than the one related to cracks with already initially fully developed cohesive zones, and related strength differences are quantified for a wide class of cohesive softening behavior. The proposed model is validated by comparing model predictions with an exact solution (available for the special case of constant cohesive tractions) and with results from reliable Finite Element analyses. The paper will be of interest for engineers involved in testing and/or in modeling of quasi-brittle media including cementitious materials and rock.     

Native and Biotechnologically Engineered Plant Proteases with Industrial Applications

Proteases occupy the most relevant position among industrial enzymes. Plant proteases have been used in medicine, detergent manufacturing, and food science for many years, but their production is diminishing in favor of those of microbial origin because lower production costs. Papain, bromelain, and ficin are the most frequently employed plant proteases, although new proteases with new and more appealing physicochemical properties for industry are still emerging. DNA technology and genetic engineering shall play, without a doubt, an important role for the production of these proteases at the industrial level. The present review focuses on the applications of traditional plant proteases as well as new proteases discovered during the last 20 years, some of which have already been genetically engineered either to increase production or to strengthen some of their physicochemical properties. The review also refers to the protease classification, action pattern, and main characteristics.