A comprehensive review of water quality indices (WQIs): history, models, attempts and perspectives.

Water quality index (WQI) is one of the most used tools to describe water quality. It is based on physical, chemical, and biological factors that are combined into a single value that ranges from 0 to 100 and involves 4 processes: (1) parameter selection, (2) transformation of the raw data into common scale, (3) providing weights and (4) aggregation of sub-index values. The background of WQI is presented in this review study.

Performance Modeling of Spherical Capsules during Mixing of Self-Consolidating Concrete.

Autonomous healing is a very promising technique in self-healing concrete systems. For capsules to achieve their anticipated performance, they should be able to survive the harsh mixing conditions of concrete, yet rupture upon concrete cracking. At present, there are no standard test methods, either experimental or analytical, for determining the capsule survival rate during concrete mixing.

Geochemical signature of the bed sediments at the outlet of the Ibrahim River (Lebanon): temporal variation.

Bed sediments were collected monthly at the outlet of the Ibrahim River between May 2016 and July 2017. Their physical and chemical characteristics were studied to highlight the impact of seasonal variations and discharge on the sediments' geochemical signatures. Granulometric analysis showed that samples collected after rain events contained abundant sand fractions (> 80%), while the clay fraction was more present at the beginning of the dry season, at low monthly average flows (1 m/s).

Probability Characteristics of a Crack Hitting Spherical Healing Agent Particles: Application to a Self-Healing Cementitious System.

A geometric model is developed to statistically study the probability characteristics of crack intersecting self-healing capsules with a structured random distribution in a cement paste mix. To evaluate the probability of a crack intersecting encapsulated particles, the fill ratio of the crack, and the depth of the first-hit capsule, Monte Carlo simulations are performed. The variables are the crack geometry, i.

Performance of Capsules in Self-Healing Cementitious Material.

Encapsulation is a very promising technique that is being explored to enhance the autonomous self-healing of cementitious materials. However, its success requires the survival of self-healing capsules during mixing and placing conditions, while still trigger the release of a healing agent upon concrete cracking. A review of the literature revealed discontinuities and inconsistencies in the design and performance evaluation of self-healing cementitious material.