Sintering ZrO2/TiC Composites with TiH2: The Role of Transient Liquid Phase and of Substoichiometry

Sintering tetragonal ZrO₂ with 35 vol% TiC results in a microstructure where all grain facets are free of amorphous interfaces independent of sintering aids as TiH₂ or MgO/ Y₂O₃; grain sizes are below 1 μm. With substoichiometric TiC_1-x, a relative density of 95% and closed porosity are obtained at a lower sintering temperature than with stoichiometric TiC, but subsequent cladless hot isostatic pressing (HIP) is required to achieve 99% density. High densities of 98% accompanied by good mechanical properties become possible by pressureless sintering with the use of TiH₂. MgO/Y₂O₃ doping also promotes densification, but results in less transformable zirconia and increases the number and size of amorphous triple junctions. The consequences are a lower fracture toughness and strength.     

Strategie für eine Konversion der Chlorchemie

Strategy for Conversion of Chlorine Chemistry . After years of discussion about ?cessation of chlorine chemistry”?, the study entitled ?Conversion of Chlorine Chemistry”? [1] commissioned by the Environmental Ministry of the State of Hesse in Germany and undertaken by Prognos AG provides the very first detailed comparative ecological and economical assessment of production process and products of ?chlorine chemistry”? and industrially feasible alternatives and presents a strategy for partial transformation. This accomplished on the basis of a systematic assessment of risks and benefits, as demanded by the Geman parliametary commission ?Protection of Humankind and the Environment”?.     

Structural engineering of nanoporous anodic aluminium oxide by pulse anodization of aluminium

Nanoporous anodic aluminium oxide has traditionally been made in one of two ways: mild anodization or hard anodization. The first method produces self-ordered pore structures, but it is slow and only works for a narrow range of processing conditions; the second method, which is widely used in the aluminium industry, is faster, but it produces films with disordered pore structures. Here we report a novel approach termed "pulse anodization" that combines the advantages of the mild and hard anodization processes. By designing the pulse sequences it is possible to control both the composition and pore structure of the anodic aluminium oxide films while maintaining high throughput. We use pulse anodization to delaminate a single as-prepared anodic film into a stack of well-defined nanoporous alumina membrane sheets, and also to fabricate novel three-dimensional nanostructures.     

Querung des Elbe‐Seitenkanals und des Mittellandkanals mittels Horizontal‐Directional‐Drilling für eine 380‐km‐Pipeline

Crossing of the Elbe‐Seitenkanal and the Mittellandkanal using HDD‐Technology for a 380 km long pipeline. The federal network of waterways and canals today comprises approximately 7500 km of inland waterways. Not restricted to economic use in transportation, the waterways also have a function in the water supply and distribution (water for industry and agriculture, flood protection etc.). As owner of federal waterways, the Federal Republic of Germany, according to the Basic law, section 87 and 89, manages these by an independent administrative authority, the Wasser‐ und Schifffahrtsverwaltung des Bundes (WSV), localy represented by the appropriate office, the Wasser‐ und Schifffahrtsamt (WSA). The WSA acts according to § 31 WaStrG as authorizing agency for river‐ and navigation‐specific police approval of third‐party installations intended for crossing or culverting the Federal Waterway route, as in this case. In the course of constructing a 380 km long pipeline from Stade to Teutschenthal (PST) a total of 203 horizontal directional drillings (HDD) were carried out. 24 of them concerned the crossing of big rivers and channels. Two technically extremely demanding projects proved to be the crossing of the Elbe‐Seitenkanal (ESK) and the crossing of the Mittellandkanal (MLK).     

Acetylation of faba bean legumin: conformational changes and aggregation

The effect of progressive acetylation upon the conformation of the 11S globulin legumin from faba bean has been studied using chemical analysis, UV, fluorescence and CD spectroscopy, viscometry and analytical ultracentrifugation. The modification did not induce complete dissociation of the oligomeric protein. Only 30% of the protein was found to be a dissociated 3S subunit after excessive acetylation, whereas 70% was a dimeric legumin aggregate with a molecular mass of about 700 kDa. The aggregation of the highly modified legumin in high‐ionic‐strength buffer solution leads to soluble higher legumin oligomers. The acetylation resulted in a moderate molecular expansion of legumin due to a changed tertiary structure, whereas the far‐UV circular dichroism spectra did not provide definitive evidence of a decrease in domain‐stabilizing β‐sheet conformations in their secondary structure. © 2000 Society of Chemical Industry     

Solid immiscibility in milk fat fractions and methods to determine their occurrence

In this work, the occurrence of solid phase immiscibility during the fractionation process of milk fat is documented. It is shown that solid phase immiscibility occurs in normal fractionation procedures, upon crystallisation at low temperatures and in particular on further fractionation of narrow melting fractions. This phenomenon results in distinct phases of crystallisation. In some cases, the initial phase yields intermediate solid levels independent of increasing supersaturation. The subsequent increase of solids content is solely a contribution of a second, independent crystallisation event. Furthermore, it could be shown that the induction time for the second crystallisation event is not influenced by the presence or absence of the first triacylglyceride group. These results clearly indicate the independence of the crystallisation of the different immiscible fractions in terms of kinetics and thermodynamics. The different processes during the crystallisation process are monitored simply by viscosimetry.     

功能性纺织材料用超声装置

本研究的目的在于开发利用超声喷嘴浸渍纺织材料的新方法,使纺织品具有既定的功能性,并为进一步应用纳米技术以获得功能化产业用纺织品,以及服装用和装饰用纺织品打下技术基础。     

拉幅干燥机的计算流体力学模拟

计算流体力学模拟可检测拉幅干燥机内的气体流动过程,并对喷嘴指板后端和通风机上端潜在的问题区域进行检测。蒸发过程的模拟表明,织物表面温度与水分的分布不均匀。然而,由于缺乏设备对实验模拟数据进行认征,故无法判断其可靠性。