Oxy-fuel combustion of pulverized coal: Characterization, fundamentals, stabilization and CFD modeling

Ultrasonic irrigation of the root canal can be performed with or without simultaneous ultrasonic instrumentation. When canal shaping is not undertaken the term passive ultrasonic irrigation (PUI) can be used to describe the technique. In this paper the relevant literature on PUI is reviewed from a MEDLINE database search. Passive ultrasonic irrigation can be performed with a small file or smooth wire (size 10-20) oscillating freely in the root canal to induce powerful acoustic microstreaming. PUI can be an important supplement for cleaning the root canal system and, compared with traditional syringe irrigation, it removes more organic tissue, planktonic bacteria and dentine debris from the root canal. PUI is more efficient in cleaning canals than ultrasonic irrigation with simultaneous ultrasonic instrumentation. PUI can be effective in curved canals and a smooth wire can be as effective as a cutting K-file. The taper and the diameter of the root canal were found to be important parameters in determining the efficacies of dentine debris removal. Irrigation with sodium hypochlorite is more effective than with water and ultrasonic irrigation is more effective than sonic irrigation in the removal of dentine debris from the root canal. The role of cavitation during PUI remains inconclusive. No detailed information is available on the influence of the irrigation time, the volume of the irrigant, the penetration depth of the instrument and the shape and material properties of the instrument. The influence of irrigation frequency and intensity on the streaming pattern as well as the complicated interaction of acoustic streaming with the adherent biofilm needs to be clarified to reveal the underlying physical mechanisms of PUI.

/pdf/passive-ultrasonic-irrigation-of-the-root-canal-a-review-of-rc2kflfgov.pdf

Passive ultrasonic irrigation of the root canal: a review of the literature.

Flow regime diagrams for gas-solid fluidization and upward transport

Biotechnology for odor and air pollution control , Biotechnology for odor and air pollution control , کتابخانه دیجیتال جندی شاپور اهواز

Biotechnology for Odor and Air Pollution Control

Aim To study using computer simulation the effect of irrigant flow rate on the flow pattern within a prepared root canal, during final irrigation with a syringe and needle.



Methodology  Geometrical characteristics of a side-vented endodontic needle and clinically realistic flow rate values were obtained from previous and preliminary studies. A Computational Fluid Dynamics (CFD) model was created using FLUENT 6.2 software. Calculations were carried out for five selected flow rates (0.02–0.79 mL sec−1) and velocity and turbulence quantities along the domain were evaluated.



Results  Irrigant replacement was limited to 1–1.5 mm apical to the needle tip for all flow rates tested. Low-Reynolds number turbulent flow was detected near the needle outlet. Irrigant flow rate affected significantly the flow pattern within the root canal.



Conclusions  Irrigation needles should be placed to within 1 mm from working length to ensure fluid exchange. Turbulent flow of irrigant leads to more efficient irrigant replacement. CFD represents a powerful tool for the study of irrigation.

http://www.endoexperience.com/documents/Boutsioukis-ComutationalFluidDynamics.pdf

Irrigant flow within a prepared root canal using various flow rates: a Computational Fluid Dynamics study

An overview of pneumatic conveying systems and performance single phase flow in pneumatic conveying systems fluid and particle dynamics fundamentals flow regimes in vertical and horizontal conveying principles of pneumatic conveying feeding of pneumatic conveying systems flow in standpipes and gravity conveyors an overview of high pressure systems including long distance and dense phase pneumatic conveying systems gas-solids separation the flow behaviour of solids from silos wear in pneumatic conveying systems ancillary equipment control of pneumatic transport instrumentation system design and worked examples.

Pneumatic Conveying of Solids : A theoretical and practical approach

Nomenclature an overview of pneumatic conveying systems and performance single phase flow in pneumatic conveying systems fluid and particle dynamics fundamentals flow regimes in vertical and horizontal conveying principles of pneumatic conveying feeding of pneumatic conveying systems flow in standpipes and gravity conveyors overview of high pressure systems including long distance and dense phase pneumatic conveying systems gas-solids separation some comments on - the flow behaviour of solids from silos, wear in pneumatic conveying systems, ancilliary equipment control of pneumatic transport instrumentation system design and worked examples

Pneumatic Conveying of Solids

In pneumatic conveying, particles are generally in suspension in a turbulent gas stream. The question of drag on a single particle, and the effects of Reynolds number, particle shape and roughness, voidage, turbulence intensity and scale of turbulence, acceleration, etc. on drag are relevant to pneumatic conveying. These factors will be discussed in this chapter. Equations for calculating important properties such as drag coefficient, terminal velocity, minimum fluidization velocity, and the equation for flow through a packed bed are presented. The characteristics of a powder in terms of its fluidization behaviour are relevant to pneumatic conveying, and will also be discussed.

Fluid and Particle Dynamics

Pneumatic conveying of solids : a theoretical and practical approach

Chapter 6 gets down to the basic principles, analysis and design on pneumatic conveying systems. The system is broken down into its major components and energy requirements and relates the physics of gas–solid transport to the practical pressure loss for design purposes. The various components of the system are considered in details with diagrams showing the behavior of the system as well as provided basic design equations for the student and practitioner.

R. Marcus

Papers

Pneumatic Conveying of Solids : A theoretical and practical approach

Pneumatic Conveying of Solids

Fluid and Particle Dynamics

Pneumatic conveying of solids : a theoretical and practical approach

Principles of pneumatic conveying