Search results for " softening."

Dynamic mode rheology of cement and tricalcium silicate pastes from mixing to setting

2001

Dynamic mode rheometry was used to study the evolution of the structure of cement and pure tricalcium silicate pastes from mixing up to setting and even after setting, together with the nature of the forces responsible for the mechanical properties of the pastes. A special mixer-type tool was used to study rheology during the very first minutes following the end of mixing, which are out of reach with classical tools. Both kinds of pastes have the same behavior. It was found that the main evolution of the structure of the pastes occurs during the very first minutes following the end of mixing, while there is no change in interparticular forces up to setting and even a few hours later. Settin…

1-METHYLCYCLOPROPENE DELAYS RIPENING AND IMPROVES POSTHARVEST QUALITY OF WHITE FLESH LOQUAT

2015

The ethylene inhibitor 1-methylcyclopropene (1-MCP) delayed ripening and improved postharvest fruit quality of loquat (Eriobotrya japonica Lindl.). 1-MCP was used on the white flesh sub-acid loquat cultivars ‘Claudia’ and ‘BRT20’ to evaluate the possible effect on fruit ripening and to prevent negative effects of cold storage, like internal browning and flesh leatheriness. 1-MCP was applied at 2°C for 20 h and concentrations of 1 and 5 μl L-1. After 1-MCP treatment fruit were held at 2°C for 7, 14, and 21 days and then moved to 18°C for 5 days. Fruit flesh firmness, titratable acidity (TA), total soluble content (TSS), weight loss, internal browning and flesh leatheriness were evaluated at …

Interphase Model and Phase-Field Approach for Strain Localization

2020

Quasi-brittle materials subjected to a high level of mechanical solicitations see the development in relatively narrow zone of micro-cracks that coalesce into stress free cracks. In this work, the problem of strain localization in elastoplastic materials exhibiting softening has been approached by applying the interphase model together with the phase-field theory. In particular, the narrow zone where strains concentrate, usually named process zone or localization band, is kinematically modeled using the interphase model, while the phase-field variable is introduced to regularize the contact strains at the interface between the plastic strain band and the surrounding material. This correspon…

Donnan dialysis for tap-water softening

2018

In this presentation, Abdusalam Alhadid, started by introducing the problem of hard water in both domestic and industrial applications,caused by an excess of calcium and magnesium ions. It significantly decreases thelifetime and efficiency of equipment which has negative technical and economic consequences. Existing water softening technologies have several disadvantages, such as a high chemical use (crystallization, ion exchange), water and energy consumption (nanofiltration)

A phase-field model for strain localization analysis in softening elastoplastic materials

2019

Abstract The present paper deals with the localization of strains in those structures consisting of materials exhibiting plastic softening response. It is assumed that strain localization develops in a finite thickness band separated from the remaining part of the structure by weak discontinuity surfaces. In view of the small thickness of the band with respect to the dimensions of the structure, the interphase concept is used for the mechanical modeling of the localization phenomenon. We propose a formulation for the quasi-static modeling of strain localization based on a phase-field approach. In this sense, the localization band is smeared over the volume of the structure and a smooth tran…

Reversible stress softening of collagen based networks from the jumbo squid mantle (Dosidicus gigas).

2014

Dosidicus gigas is the largest and one of the most abundant jumbo squids in the eastern Pacific Ocean. In this paper we have studied the muscle of the mantle of D. gigas (DGM). Morphological, thermal and rheological properties were assessed by means of atomic force microscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, differential scanning calorimetry, thermogravimetry and oscillatory rheometry. This study allowed us to assess the morphological and rheological properties of a collagen based network occurring in nature. The results showed that the DGM network displays a nonlinear effect called reversible stress softening (RSS) that has been previously described for …

Some observations on the regularizing field for gradient damage models

2000

Gradient enhanced material models can potentially preserve well-posedness of incremental boundary value problems also after the onset of strain softening. Gradient dependent constitutive relations are rooted in the assumption that some scalar or tensor field, which appears in the yield function, has to be enriched by adding a term involving its second-order gradient field. For gradient-dependent plasticity this term is universally accepted to be the equivalent plastic strain. For gradient-dependent damage models different choices have been presented in the literature. They all possess the desired regularization of the solution, but they are not identical as regards the structural response. …

Effects of 1-Methylcyclopropene on post harvest quality of white flesh loquat (Eriobotrya japonica Lindl.) fruit.

2014

Towards the implementation of circular economy in the water softening industry: A technical, economic and environmental analysis

2020

Abstract To reduce the environmental impact of the industrial sectors, circular strategies should be implemented to purify the effluents and recover raw materials. In this context, a novel integrated methodological approach is proposed to identify the most suitable strategy to improve the sustainability of the water softening industry via the treatment and recycling of the produced wastewater. Different concentration technologies and energy supply systems are compared to find economically feasible and environmentally friendly treatment systems. The investigated chains present the same pre-treatment step (nanofiltration and crystallization) and different concentration technologies: Multi-Eff…

Techno-economic assessment of multi-effect distillation process for the treatment and recycling of ion exchange resin spent brines

2019

Abstract A treatment chain including nanofiltration, crystallization and multi-effect distillation (MED) is for the first time proposed for the treatment of an effluent produced during the regeneration of Ion Exchange resins employed for water softening. The goal is to recover the minerals and to restore the regenerant solution to be reused in the next regeneration cycle. MED is the most crucial unit of the treatment chain from an economic point of view. A techno-economic analysis on the MED unit was performed and a novel performance indicator, named Levelized Brine Cost, was introduced as a measure of the economic feasibility of the process. Different scenarios were analysed, assuming diff…