Existing eurocodes applied to a membrane structure

This article tries gaining insight in the effect of the partial factor starting by the analysis of a steel cable net structure according to Eurocode 3. Eurocode specifies a value of 1.35 for the partial factor for prestress. A cable net structure built in 1958, was used as a case study. In spite of the lack of design guidelines and calculation tools 58 years ago, the analysis according to the current design standard Eurocode 3 for steel shows that the results match quite well with the original calculation. Generally speaking, a reduction in the cross-section areas is observed using Eurocode 3. For the considered steel cable net structure a weight saving of 17% for a partial factor for prestress 1.35 is obtained. If a partial factor for the prestress 1.0 could be considered, the weight reduction would be 4% more. Furthermore, the article investigates the effect of the partial factor for prestress (1.0 or 1.35), there prestress contributes to the stiffness in the non-lineair structural behaviour of membrane structures. The value of the partial factor for prestress to be considered is a source of disagreement between experts in different countries. With a similar geometry as the steel cable net structure, a membrane structure is designed and analysed. For the primary steel structure the partial factor for prestress 1.35 has to be applied. A 2% weight saving for the pretension factor 1.0 versus 1.35 is obtained if the tensile surface including the membrane and the edge cables is considered separate from the primary structure. A sound conclusion though requires a thorough in-depth study for different shapes and for different membrane types

Understanding the cooking behavior of carrots (Daucus carota) after pulsed electric field and mild thermal pretreatment

status: Published onlin

Pulsed electric fields improve carrot texture preservation during thermal processing through demethylesterification and crosslinking of pectin

status: Published onlin

Pulsed electric field and mild thermal processing affect the cooking behaviour of carrot tissues (Daucus carota) and the degree of methylesterification of carrot pectin

For the first time, the effect of pulsed electric field (PEF) and mild thermal processing on the texture of cortex and vascular carrot tissue during subsequent thermal processing (i.e. cooking behaviour) was compared and the degree of methylesterification (DM) of pectin from the pretreated tissues was investigated. The PEF and mild thermal pretreatment slowed down the cooking behaviour of the carrot tissues, especially when the pretreatments were combined. The DM of pectin from vascular tissue was lowered after both types of pretreatments, the effect being most pronounced in the case of the combination of the PEF and mild thermal pretreatment. In contrast, the DM of cortex pectin only decreased after the mild thermal pretreatment and after the combination pretreatment. This study demonstrates that besides mild thermal pretreatments also PEF pretreatments can be considered in the context of texture preservation of thermally processed fruits and vegetables.status: publishe