The article describes the construction and testing of a functional model of an innovative warp – knitting machine for technical spatial knitted fabrics with an original structure. Design assumptions regarding the geometrical, kinematic and driving characteristics of the machine are described. The functional model as well as its physical implementation as a research stand are presented. The production phases of the 3D knitted fabric are also demonstrated. The research results are described and their importance for the construction of a machine prototype of the production version are emphasised.
Additional supporting information may be found in the online version of this article at the publisher's web site.Dear Sir, Phosphorus forms one of the most numerous group of oxoanions (obviously they exist as neutral compounds, acids, salts). The most common phosphorus oxyanion is orthophosphate anion PO 4 3À . Other phosphorus oxoanions are pyrophosphate P 2 O 7
The promotion of Fischer-Tropsch catalysts 10%Co/Al 2 O 3 , 10%Co/SiO 2 , 10%Co/TiO 2 by 0.5% Ru and the modification of supports by 8.5 wt% ZrO 2 have been studied. The following properties: catalyst specific surface area as well as reducibility and dispersion of metallic phase were studied by different techniques: BET, TPR, and H 2 chemisorption. The modification of supports by nonreducible ZrO 2 , results in a decrease of cobalt oxide reduction on Al 2 O 3 and TiO 2 but not on SiO 2 supports. Additionally the enhancement of cobalt dispersion was found for all catalysts with ZrO 2 modified supports. The impact of Ru promotion is likely due to the stabilization of applied supports, prevention or blockage of interaction between surface Co species and support and an increase in cobalt oxide reducibility to the catalytically active metallic cobalt phase.
The most advantageous geometry of the warp feeding system was determined from the viewpoint of compensating temporary changes in the warp length during the technological cycle of a four-comb warp-knitting machine. Dynamic simulations of the feeding system were carried out for 3 different lengths of the shift of the slider with a guide bar – designating variants (series) of the cross-sectional sizes of the 3D knitted fabrics. The courses of instantaneous warp tensions during the operating cycle of the warp-knitting machine were presented. Limit dynamic loads of the warp were determined and presented as a function of natural frequency of the whip roller. Based on the criterion of the smallest dynamic loads of the warp, the optimum natural frequencies of the whip roller were determined. In the analyzed range of the whip roller parameters, they are 3–6 times greater than the operation frequency of the warp-knitting machine.
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