Evaluation of a diffusive sampler for formaldehyde.

P A Ellwood; J A Groves; M I Pengelly

doi:10.1093/annhyg/34.3.305

Home/Archive/PubMed

PubMed · 2372191

Evaluation of a diffusive sampler for formaldehyde.

P A Ellwood·J A Groves·M I Pengelly

View original source ↗Export metadata ↓

Abstract

A diffusive sampling system, using a commercially available liquid sorbent badge, has been evaluated for the determination of airborne formaldehyde concentrations according to the U.K. Health and Safety Executive protocol. The results of laboratory and field experiments are presented. The results obtained using the diffusive sampler during field measurements were about 10% higher overall than those obtained using a conventional pumped sampler.

Explore related subjects

Diffusion Environmental Monitoring Equipment Design Evaluation Studies as Topic Formaldehyde Humans Journal Article

Keep this discovery

Explore connections, maps & timelines

BibTeX RIS

P A Ellwood, J A Groves, M I Pengelly. 1990. Evaluation of a diffusive sampler for formaldehyde.. https://doi.org/10.1093/annhyg%2F34.3.305

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed2003

Modeling controlled nutrient release from polymer coated fertilizers: diffusion release from single granules.

A comprehensive model describing the complex and "non-Fickian" (mathematically nonlinear) nature of the release from single granules of membrane coated, controlled release fertilizers (CRFs) is proposed consisting of three stages: i. a lag period during which water penetrates the coating of the granule dissolving part of the solid fertilizer in it ii. a period of linear release during which water penetration into and release out occur concomitantly while the total volume of the granules remains practically constant; and iii. a period of "decaying release", starting as the concentration inside the granule starts to decrease. A mathematical model was developed based on vapor and nutrient diffusion equations. The model predicts the release stages in terms of measurable geometrical and chemophysical parameters such as the following: the product of granule radius and coating thickness, water and solute permeability, saturation concentration of the fertilizer, and its density. The model successfully predicts the complex and "sigmoidal" pattern of release that is essential for matching plant temporal demand to ensure high agronomic and environmental effectiveness. It also lends itself to more complex statistical formulations which account for the large variability within large populations of coated CRFs and can serve for further improving CRF production and performance.

Diffusion↗

PubMed2003

Modeling controlled nutrient release from a population of polymer coated fertilizers: statistically based model for diffusion release.

A statistically based model for describing the release from a population of polymer coated controlled release fertilizer (CRF) granules by the diffusion mechanism was constructed. The model is based on a mathematical-mechanistic description of the release from a single granule of a coated CRF accounting for its complex and nonlinear nature. The large variation within populations of coated CRFs poses the need for a statistically based approach to integrate over the release from the individual granules within a given population for which the distribution and range of granule radii and coating thickness are known. The model was constructed and verified using experimentally determined parameters and release curves of polymer-coated CRFs. A sensitivity analysis indicated the importance of water permeability in controlling the lag period and that of solute permeability in governing the rate of linear release and the total duration of the release. Increasing the mean values of normally distributed granule radii or coating thickness, increases the lag period and the period of linear release. The variation of radii and coating thickness, within realistic ranges, affects the release only when the standard deviation is very large or when water permeability is reduced without affecting solute permeability. The model provides an effective tool for designing and improving agronomic and environmental effectiveness of polymer-coated CRFs.

Diffusion↗

PubMed2003

Preparation of solid lipid nanoparticles by a solvent emulsification-diffusion technique.

A preparation method for nanoparticles based on the emulsification of a butyl lactate or benzyl alcohol solution of a solid lipid in an aqueous solution of different emulsifiers, followed by dilution of the emulsion with water, was used to prepare glyceryl monostearate nanodispersions with narrow size distribution. To increase the lipid load the process was conducted at 47+/-2 degrees C and in order to reach submicron size a high-shear homogenizer was used. Particle size of the solid lipid nanoparticles (SLN) was affected by using different emulsifiers and different lipid loads. By using lecithin and taurodeoxycholic acid sodium salt, on increasing the GMS percentage from 2.5 to 10% an increase of the mean diameter from 205 to 695 nm and from 320 to 368nm was observed for the SLN prepared using benzyl alcohol and butyl lactate, respectively. Transmission electron micrographs of SLN reveal nanospheres with a smooth surface.

Diffusion↗