转杯纺生产花式纱

描述了转杯纺纱机Autocoro的最新开发成果之一--Fancynation花式纱系统.详细讨论了用于牛仔纱的特殊花型、卷绕过程、接头和使用Fancynation生产多种花式纱的工艺.     

使用精梳落棉生产Autocoro针织纱线

原材料成本推动Autocoro纺纱工艺发展.最近几年纱线生产成本在总成本中的份额不断地在增加.以前纱线生产成本也许占总成本的一半,目前已达75%.介绍了纺纱厂应对这种趋势的方法.     

Formation and Properties of 2Tb2O3· Al2O3

The compound 2Tb₂O₃· Al₂O₃ was fabricated, and selected properties were investigated. The room-temperature X-ray diffraction pattern was indexed and the lattice parameters were calculated. Powder density was determined and used to calculate the number of molecules per unit cell (Z). This allowed calculation of a theoretical density. The material was characterized with regard to thermal expansion and indentation hardness and toughness. It was found to exhibit a rapid and reversible polymorphic transformation at high temperature.     

Preparation, Microstructure, and Mechanical Properties of Silicon Carbide–Dysprosia Composites

Composites of silicon carbide (SiC) with up to 30 vol% of dysprosia (Dy₂O₃) were fabricated by hot pressing and hot isostatic pressing. The effects of Dy₂O₃ dispersions on the microstructure and on selected mechanical properties of the composites were investigated. When 10-15 vol% of Dy₂O₃ was dispersed in the SiC matrix, the fracture toughness increased by ∼40%, whereas the flexural strength was comparable to that of unreinforced SiC. The increased fracture toughness was due to crack deflection, in conjunction with crack-interface grain bridging, and was not related to a phase transformation of Dy₂O₃ in the matrix.     

Control of Interfacial Properties through Fiber Coatings: Monazite Coatings in Oxide–Oxide Composites

Fiber pushout tests were used to quantify the effects of fiber coating thickness on the mechanical properties of two model composite systems: a monazite-coated (LaPO₄-coated) alumina (Al₂O₃) fiber in an Al₂O₃ matrix and a LaPO₄-coated yttrium aluminum garnet (YAG) fiber in an Al₂O₃ matrix. Interface properties were quantified using the Liang and Hutchinson (LH) pushout model and mechanistically rationalized by considering the change in residual thermal stresses with changes in the coating thickness. Measures of the pure Mode II interfacial fracture energy, the coefficient of friction, and a radial clamping pressure are extracted by fitting the LH equations to the experimental results. Using the approach that has been developed herein, a methodology is available for measuring the interfacial properties, predicting the effect of coating thickness, and selecting the coating thickness to     

Potassium‐Based Geopolymer Composites Reinforced with Chopped Bamboo Fibers

Bamboo is a fast‐growing, readily available natural material with tensile specific strength equivalent to that of steel (250–625 MPa/g/cm³). In the pursuit of sustainable construction materials, a composite was made with potassium polysialate siloxo geopolymer as the matrix and randomly oriented chopped bamboo fibers (Guadua angustifolia) from the Amazon region as the reinforcement. Four‐point flexural strength testing of the geopolymer composite reinforced with bamboo fibers was carried out according to ASTM standard C78/C78M‐10^e1. Potassium‐based metakaolin geopolymer reinforced with 5 wt% (8 vol%) untreated bamboo fibers yielded 7.5 MPa four‐point flexural strength. Scanning electron microscopy and optical microscopy were used to investigate the microstructure. In addition, X‐ray diffraction was used to confirm the formation of geopolymer.     

Phase Transformations in Dicalcium Silicate: II, TEM Studies of Crystallography, Microstructure, and Mechanisms

The crystallography, microstructures, and phase transformation mechanisms in dicalcium silicate (Ca₂SiO₄) were studied by TEM. Three types of superlattice structures were observed in the α'_L and β phases. Almost all β grains were twinned and strained. Symmetry-related domain structures inherited from previous high-temperature transformations were observed in β grains. Both the α→α'_H and α'_L→β transformations were considered to be ferroelastic, and spontaneous strains were calculated. In terms of the crystal structures, the major driving force for the β→γ transformation is proposed to be strains and cation charge repulsions in the β structure. This mechanism can be displacive, but it needs to overcome a comparatively high energy barrier.     

SiCf/O′-SiAlON composite: properties and oxidation retained properties

A composite of O′SiAlON (Si_2-xAl_xN_2-xO_1+x, with x 0.14) reinforced with 20 vol.% SiC monofilaments was fabricated by hot-pressing, at 1600°C, for 2 h under 34 MPa pressure. The mechanical and interfacial properties of the composites, as-fabricated as well as post-oxidized, were, investigated. The composite exhibited a significant improvement in ultimate flexure strength (640 MPa) and work of fracture (42 kJ m⁻²) compared with that (350 MPa and 1.8 kJ m⁻², respectively) of the monolithic material. These mechanical properties were slightly increased after the composite was heat treated for 24 h in air at 1200 and 1300°C. However, the composite exhibited a significant degradation in ultimate strength, while the work of fracture (WOF) remained unchanged after exposure in air at temperatures beyond 1400°C. The as-fabricated composite revealed a low interfacial shear strength (6.2 MPa) and a frictional sliding stress (3.2 MPa). After the composite was oxidized at elevated temperatures, the interfacial bonding and sliding stresses were reduced to noticeable extents, resulting from the degradation of the carbon coating layer of the SiC monofilaments.