By a Computational Fluid Dynamics software named Fluent, the influence that the permeability, gas emission intensity of goaf and turbulent parameters in working face have on the numerical simulation was studied. The results show that: the permeability and gas emission intensity of goaf have great influence on the migration law of gas and goaf air leakage, causing great impact on the gas concent...

This study investigates the effects of fabric properties and ultrasonic welding on performance surgical gowns. For this purpose, eight spunlace fabrics with different structural were provided. First, fabrics’ thickness, tensile strength, elongation at break, air permeability, drape behavior, surface friction investigated. Then sewn sewing machine. Afterward, seam permeability behavior tested. T...

Introduction: Evaluation of upper airway space is a routine procedure in orthodontic diagnosis and treatment planning. Although limited insofar as they provide two dimensional images of three-dimensional structures, lateral cephalometric radiographs have been used routinely to assess airway space permeability. Cone-Beam Computed Tomography (CBCT) has contributed to orthodontics with information...

Epidemiological and environmental chamber studies in man, and toxicological studies in animals, have provided valuable insights into the biological effects, the mechanisms of action, and the dose-response characteristics of some major air pollutants. This review describes the information currently available on air pollutant effects in man, as the result of experimental studies. There are certai...

This paper investigates the permeability of several multi-layered, woven filter media using air, water and bubble point methods. Estimated filter efficiencies from the bubble point measurements were then compared to a new sonic challenge test method where precision microspheres are fluidised through the pores. Inconsistencies in the bubble point filter efficiencies were found to be dependent on...

In this paper, it is shown that by modulating a plasma arc, as well the use of an air-gas mix-ture (air with propane-butane), you can signifi-cantly increase strength coating coat-ing, coefficient powder, reduce gas permeability and wear resistance powder coatings.

Nowadays, membrane processes are widely used for high purity Nitrogen production. Separation of air by membranes is a flexible process in which the investment and operational costs are lower than for example adsorption or cryogenic processes. Such processes are based on relative permeability of air components which are transported by the pressure difference between two sides of the membrane. M...

In the production of polyethylene foams by extrusion with alkanes as a blowing agent, significant changes in the dimensions of extruded products are encountered. The dimensional stability of a foam with a structure of closed cells is improved by blending the polymer with small amounts of a low molecular weight additive. It is believed that the dimensional stability is related to the ratio of th...