Filtration of contaminated breathing gases is a necessary measure in mechanical ventilation. There are two types of filters available for filtration of breathing gases: mechanical filters and electrostatic filters. Filter efficiency can be established through a number of means, the most stringent being the High Efficiency Particulate Air (HEPA) test. While a variety of HEPA-grade filters are av...

Hydrogen fluoride (HF) is a basic raw material for a wide variety of industrial products, with a worldwide production capacity of more than three million metric tonnes. A novel method for determining particulate fluoride and gaseous hydrogen fluoride in air is presented herewith. Air was sampled using miniaturised 13 mm Swinnex two-stage filter holders in a medium-flow pumping system and throug...

A method has been developed to measure aldehydes and ketones associated with atmospheric particles. Carbonyl compounds from particulate material collected on Teflon-coated glass-fiber filters were simultaneously extracted and derivatized with an appropriate 2,4-dinitrophenylhydrazine (2,4-DNPH) solution. The efficiency of this procedure utilizing various 2,4-DNPH concentrations and solvent comp...

Soot emissions from automotive applications can be reduced through on-board diesel particulate filters (DPFs): the filter gets progressively loaded by filtering the soot laden flue gases, thus causing an increasing pressure drop, until an oxidative regeneration is induced by temperature rise. Due to the complexity of the involved phenomena, a fully predictive and detailed mathematical model rep...

New simulation algorithm of soot oxidation in diesel particulate filter (DPF) is proposed. Two-dimensional finite differences scheme is used for calculation of the heat transfer in DPF (macro-scale). One dimensional model for treatment of the soot oxidation process in a separate filter channel (micro-scale) is based on a new expression for the oxidation reaction rate that is a modification of t...

In this paper we introduce a new application of time-resolved X-ray tomography (XRT) to imaging the washcoating process in catalytic monolith filters with honeycomb structure (DPF, GPF). The method is applied several alumina washcoats different particle size distributions deposited on cordierite substrate. results bring insights into drying dynamics porous filter wall as well on-wall catalyst l...

The use of high-efficiency HVAC filters is a common strategy to control exposure to airborne particulate matter in residential buildings. However, high-efficiency filters generally have a higher pressure drop and are widely assumed to have large energy penalties. In this paper, we explore the underlying theoretical energy implications of high-pressure-drop filters and we present the results of ...