Syringe irrigation in confluent canals: A sequential computational fluid dynamics assessment.

This study aims to assess the influence of root canal preparation, irrigation needle design and its placement depth in the irrigation flow of confluent canals during syringe irrigation. A mandibular molar presenting two confluent canals in its mesial root was sequentially prepared and scanned by micro-computed tomography after mechanical preparation up to ProTaper Next system sizes X2 (25/.06v), X3 (30/.

Experimental validation of a computational fluid dynamics model using micro-particle image velocimetry of the irrigation flow in confluent canals.

Aim: This study aimed to experimentally validate a computational fluid dynamics (CFD) model, using micro-particle image velocimetry (micro-PIV) measurements of the irrigation flow velocity field developed in confluent canals during irrigation with a side-vented needle.

Methodology: A microchip with confluent canals, manufactured in polydimethylsiloxane was used in a micro-PIV analysis of the irrigation flow using a side-vented needle placed 3 mm from the end of the confluence of the canals. Velocity fields and profiles were recorded for flow rates of 0.

Rheological characterization of polymeric solutions used in spray drying process.

The present works contributes with a rheological characterization of the most commonly used polymers and solvents to formulate amorphous solid dispersions by means of spray drying process: copovidone, hydroxypropyl methylcellulose (HPMC), hydroxypropyl methylcellulose acetate succinate (HPMCAS) and a copolymer of methacrylic acid and methyl methacrylate (1:1 ratio and commercially known as Eudragit L100). The organic-based solutions are characterized in terms of surface tension, shear viscosity and relaxation time. HPMC and HPMCAS solutions exhibit shear thinning behaviour, i.

Consistent lattice Boltzmann modeling of low-speed isothermal flows at finite Knudsen numbers in slip-flow regime: Application to plane boundaries.

The first nonequilibrium effect experienced by gaseous flows in contact with solid surfaces is the slip-flow regime. While the classical hydrodynamic description holds valid in bulk, at boundaries the fluid-wall interactions must consider slip. In comparison to the standard no-slip Dirichlet condition, the case of slip formulates as a Robin-type condition for the fluid tangential velocity.

Operation costs and pollutant emissions reduction by definition of new collection scheduling and optimization of MSW collection routes using GIS. The case study of Barreiro, Portugal.

This work proposes an innovative methodology for the reduction of the operation costs and pollutant emissions involved in the waste collection and transportation. Its innovative feature lies in combining vehicle route optimization with that of waste collection scheduling. The latter uses historical data of the filling rate of each container individually to establish the daily circuits of collection points to be visited, which is more realistic than the usual assumption of a single average fill-up rate common to all the system containers.

Multi-criteria GIS-based siting of an incineration plant for municipal solid waste.

Siting a municipal solid waste (MSW) incineration plant requires a comprehensive evaluation to identify the best available location(s) that can simultaneously meet the requirements of regulations and minimise economic, environmental, health, and social costs. A spatial multi-criteria evaluation methodology is presented to assess land suitability for a plant siting and applied to Santiago Island of Cape Verde. It combines the analytical hierarchy process (AHP) to estimate the selected evaluation criteria weights with Geographic Information Systems (GIS) for spatial data analysis that avoids the subjectivity of the judgements of decision makers in establishing the influences between some criteria or clusters of criteria.

Monitoring, fault detection and operation prediction of MSW incinerators using multivariate statistical methods.

This work proposes the application of two multivariate statistical methods, principal component analysis (PCA) and partial least square (PLS), to a continuous process of a municipal solid waste (MSW) moving grate-type incinerator for process control--monitoring, fault detection and diagnosis--through the extraction of information from historical data. PCA model is built for process monitoring capable of detecting abnormal situations and the original 16-variable process dimension is reduced to eight, the first 4 being able to capture together 86% of the total process variation. PLS model is constructed to predict the generated superheated steam flow rate allowing for control of its set points.

Estimation of residual MSW heating value as a function of waste component recycling.

Recycling of packaging wastes may be compatible with incineration within integrated waste management systems. To study this, a mathematical model is presented to calculate the fraction composition of residual municipal solid waste (MSW) only as a function of the MSW fraction composition at source and recycling fractions of the different waste materials. The application of the model to the Lisbon region yielded results showing that the residual waste fraction composition depends both on the packaging wastes fraction at source and on the ratio between that fraction and the fraction of the same material, packaging and non-packaging, at source.

On the effect of MSW moisture content on meeting target recycling rates.

A mathematical model to calculate the recycle rates for packaging materials from the municipal solid wastes (MSW) built from the dry mass values that are obtained from the corresponding wet masses and their respective moisture contents is presented in this work. A possible universal methodology is also described to be used with the previous model so that reliable comparisons between indicators for different regions are feasible. Furthermore, this mathematical model demonstrates the effect of the moisture content of packaging materials on their recycling rates and constitutes a fundamental tool for operators and persons responsible for MSW management to define new policies and technical measures viewing the improvement of recycling rates.

Municipal solid waste disposal in Portugal.

In recent years municipal solid waste (MSW) disposal has been one of the most important environmental problems for all of the Portuguese regions. The basic principles of MSW management in Portugal are: (1) prevention or reduction, (2) reuse, (3) recovery (e.g.