Development of a Continuous Segmented Flow Tubular Reactor and the “Scale‐out” Concept – In Search of Perfect Powders

The synthesis of powders with controlled shape and narrow particle size distributions is still a major challenge for many industries. A continuous Segmented Flow Tubular Reactor (SFTR) has been developed to overcome homogeneity and scale‐up problems encountered when using batch reactors. Supersaturation is created by mixing the co‐reactants in a micromixer inducing precipitation; the suspension is then segmented into identical micro‐volumes by a non‐miscible fluid and sent through a tube. These micro‐volumes are more homogeneous when compared to large batch reactors leading to narrower size distributions, better particle morphology, polymorph selectivity and stoichiometry. All these features have been demonstrated on single tube SFTR for different chemical systems. To increase productivity for commercial application the SFTR is being “scaled‐out” by multiplying the number of tubes running in parallel instead of scaling‐up by increasing their size. The versatility of the multi‐tube unit will allow changes in type of precipitate with a minimum of new investment as new chemistry can be researched, developed and optimised in a single tube SFTR and then transferred to the multi‐tube unit for powder production.     

Vakuumgerechte Werkstoffe und Verbindungstechnik

In Part 1 (Henning, Materials used in Vacuum Technology), the application possibilities of different materials in vacuum technology were described. Part 2 describes the most important non-detachable connections of these materials to produce components that can be used in vacuum technology. The following processes are suitable for this purpose:

• ○ Welding

• ○ Soldering

• ○ Glueing

• ○ Fusion

For this reason, these four processes will be discussed in detail here; their advantages and disadvantages described and their worthiness for use in vacuum technology indicated. It should be noted here that other nondetachable connections such as rivets, point welding, projection seam welding or roll seam welding do not meet the demands of gas tightness made in vacuum technology and cannot, therefore, be used for such purposes.     

Catalysis with homogeneous membranes loaded with nanoscale metallic clusters and their preparation

Catalytically powerful, non-porous membranes were manufactured from two highly gas permeable poly(amide imides) consisting of structures with moieties of 3,3'-dimethylnaphthidine and hexafluoroisopropylidene (6F) or hexafluoroisopropylidene 2,2-bis(phthalic acid anhydride) (6FDA) and 6F. The catalysts are pure precious metals or precious metal alloys dispersed on a nanoscale uniformly throughout the membrane. The membranes are characterized by electron microscopy, gas permeability, hydrogen uptake and, as a model reaction, the decomposition of nitrous oxide by hydrogen to nitrogen and water catalyzed by Pd/Ag. The permeance to hydrogen and nitrous oxide is round 2–10^-6 cm³ (STP) /cm²·s·cmHg for membranes of 40–50μm in thickness.     

冠带层新平台技术

子午线轮胎出现不久，就采用钢丝带束层代替了纤维带束层，这对于实现子午线轮胎提高使用寿命和改善操纵性能的潜能是必要的。     

表现出良好带束层边缘粘合性能的冠带层新材料

本文介绍了加工助剂莱茵塑分T和增塑剂A在全钢载重子午线轮胎胎面配方中的胶料性能对比，并着重考察了对胎面挤出性能和外胎性能的影响。试验结果表明，使用加工助剂能降低胎面的挤出温度，提高胎面的挤出速度；两种加工助剂相比，含莱茵塑分T的胶料老化性能、疲劳性能和分散性以及胎面挤出温度和断面气孔情况均比增塑剂A好；外胎的耐久试验均超过国家标准。     

Localization of shapes using statistical models and stochastic optimization

In this paper, we present a new model for deformations of shapes. A pseudo-likelihood is based on the statistical distribution of the gradient vector field of the gray level. The prior distribution is based on the Probabilistic Principal Component Analysis (PPCA). We also propose a new model based on mixtures of PPCA that is useful in the case of greater variability in the shape. A criterion of global or local object specificity based on a preliminary color segmentation of the image, is included into the model. The localization of a shape in an image is then viewed as minimizing the corresponding Gibbs field. We use the Exploration/Selection (E/S) stochastic algorithm in order to find the optimal deformation. This yields a new unsupervised statistical method for localization of shapes. In order to estimate the statistical parameters for the gradient vector field of the gray level, we use an Iterative Conditional Estimation (ICE) procedure. The color segmentation of the image can be computed with an Exploration/Selection/Estimation (ESE) procedure.