Energy absorption behavior of tapered and ribbed thin-walled structures under compressive crushing forces

45-51This paper investigates the energy absorption behavior of straight and tapered square, hexagonal and octagonal tubes with two types ribbed connection inside. The parameters studied are the geometry of section, rib configuration and taper angle. In this study, a numerical model is introduced and justified by both the analytical and numerical models in the literature. The results show that octagonal tubes have the highest energy absorption capacity followed by hexagonal and square sections. The ribbed profiles have better energy absorption per unit mass by an increased number of corners. The energy absorption per unit mass and crushing force efficiency decrease with increasing taper angle.Results also indicate that the tapered profile delivers more stable crushing behavior. The research findings can be used to quantify energy absorption in the design of energy absorbers for impact applications

Catalytic activity of FeZSM-5 zeolites in benzene hydroxylation by N2O: The role of geometry characterized by fractal dimensions

The fractal dimensions of FeZSM-5 zeolites were used to characterize the change in their geometry depending on different post-synthesis treatments. The fractal dimension values were estimated from the Dubinin-Astakhov isotherms of nitrogen adsorption and related to the activity of these zeolites in the benzene hydroxylation to phenol by nitrous oxide. The zeolites had two different iron contents (350 and 5800 ppm) and a Si/Al ratio of 42. The catalysts were activated by steaming (823 K) and/or calcinations in He (1323 K). The FeZSM-5 activated by steaming exhibited fractal dimensions lower than the samples activated by calcinations. The steamed samples also had activities in the benzene hydroxylation per Fe(II) site (TOF values) somewhat higher as compared to the zeolites activated by calcinations. This indicates the importance of the zeolite geometry for the reaction of bulky benzene molecule within a confined space. (c) 2005 Elsevier B.V. All rights reserved

Data for: Effects of structural properties of fillers on performances of Matrimid 5218 mixed matrix membranes

All the data, related to the structural properties of the filler materials as well as the performances of the Matrimid® MMMs, which were used in the statisical investigations are provided

Data for: Effects of structural properties of fillers on performances of Matrimid 5218 mixed matrix membranes

All the data, related to the structural properties of the filler materials as well as the performances of the Matrimid® MMMs, which were used in the statisical investigations are provided,THIS DATASET IS ARCHIVED AT DANS/EASY, BUT NOT ACCESSIBLE HERE. TO VIEW A LIST OF FILES AND ACCESS THE FILES IN THIS DATASET CLICK ON THE DOI-LINK ABOV

Relation of water adsorption capacities of zeolites with their structural properties

An investigation was carried out to determine the extent of relations between various structural properties of zeolite frameworks and their experimental water adsorption capacities. For this aim, average water capacity values were determined for different zeolite frameworks by utilizing water adsorption capacities reported in the literature for related materials. It was observed that the theoretical surface areas and volumes available for water adsorption in zeolites as well as the fractal dimensions of these materials exhibited some correlation with their experimental adsorption capacities. The results might give an indication of the potential for development of different zeolite frameworks, regarding their water adsorption capacities. Analogue materials of known zeolite framework structures, with different chemical compositions, which may allow for relatively high water adsorption capacities, may be prepared for such an improvement. The investigations may also be informative for the development of new zeolite-like adsorbents with relatively high capacities