The use of permeation tube device and the development of empirical formula for accurate permeation rate.
Summary of "The use of permeation tube device and the development of empirical formula for accurate permeation rate."
A series of laboratory experiments were conducted to assess the accuracy of permeation tube (PT) devices using a calibration gas generator system to measure permeation rate (PR) of volatile organic compounds (VOCs). Calibration gas standards of benzene, toluene, and m-xylene (BTX) were produced from PTs at varying flow rates (FR) of 20-1200mLmin(-1) and constant temperature (30°C). Results indicate that changes in flow rate greatly affected the permeation rate of each VOC at this temperature. This paper presents experimental approaches to accurately measure actual permeation rate (APR) and the derivation of empirical equations for predicted permeation rate (PPR). If the magnitude of bias is defined as the difference between PPR and the manufacturer's permeation rate (MPR), the bias was typically 19-40% for toluene (T) and 31-54% for m-xylene (X). Benzene (B) exhibited the least bias of 1.4-18.8%, nevertheless our PPR values for benzene were more reliable at lower flow rates (0.75-1.20%). This study highlights the importance of flow rate and associated pressure changes as a key to accurate permeation rate estimation from permeation tube devices.
Department of Environment & Energy, Sejong University, 98 Goon Ja Dong, Seoul 143-747, South Korea.
This article was published in the following journal.
Name: Journal of chromatography. A
- PubMed Source: http://www.ncbi.nlm.nih.gov/pubmed/22129573
- DOI: http://dx.doi.org/10.1016/j.chroma.2011.11.007
Medical and Biotech [MESH] Definitions
The transparent anterior portion of the fibrous coat of the eye consisting of five layers: stratified squamous CORNEAL EPITHELIUM; BOWMAN MEMBRANE; CORNEAL STROMA; DESCEMET MEMBRANE; and mesenchymal CORNEAL ENDOTHELIUM. It serves as the first refracting medium of the eye. It is structurally continuous with the SCLERA, avascular, receiving its nourishment by permeation through spaces between the lamellae, and is innervated by the ophthalmic division of the TRIGEMINAL NERVE via the ciliary nerves and those of the surrounding conjunctiva which together form plexuses. (Cline et al., Dictionary of Visual Science, 4th ed)
A very complex, but reproducible mixture of at least 177 C10 polychloro derivatives, having an approximate overall empirical formula of C10-H10-Cl8. It is used as an insecticide and may reasonably be anticipated to be a carcinogen: Fourth Annual Report on Carcinogens (NTP 85-002, 1985). (From Merck Index, 11th ed)
The removal of secretions, gas or fluid from hollow or tubular organs or cavities by means of a tube and a device that acts on negative pressure.
Safety-based Medical Device Withdrawals
Removal of a MEDICAL DEVICE from the market due to the identification of an intrinsic property of the device that results in a serious risk to public health.
The two longitudinal ridges along the PRIMITIVE STREAK appearing near the end of GASTRULATION during development of nervous system (NEURULATION). The ridges are formed by folding of NEURAL PLATE. Between the ridges is a neural groove which deepens as the fold become elevated. When the folds meet at midline, the groove becomes a closed tube, the NEURAL TUBE.
In this study, the performance of permeation tube (PT) devices for the generation of VOC calibration gas was examined by successively generating BTX gas at five temperatures (30, 50, 70, 80, and 100°...
The development and operation of a highly accurate primary gas facility for the dynamic production of mixtures of nitrogen dioxide in nitrogen based on continuous weighing of a permeation tube and acc...
PURPOSE: Compound permeation through stratum corneum-stripped skin is generally greater than that through full-thickness skin. In addition, epidermis-to-dermis permeation profile should be the same as...
Introduction: With the incorporation of edge activators into the lipid bilayer structure, elasticity properties are given to liposomes. Regardless of the debate over the precise permeation mechanism o...
An in vitro model was used to simulate the intestinal permeation of calcium ions depending on the type of salt (carbonate, fumarate, citrate, or gluconate), its concentration (1.0, 2.5, 5.0, or 10 mM/...
During radiation treatment for head and neck cancer a large percentage of patients at Mayo Clinic Rochester develop the need for tube feeding to meet nutrition and hydration needs. These p...
A study to evaluate the growth and development of term infants fed either a marketed cow's milk formula, or an experimental cow's milk formula with prebiotics + a different calcium source...
The purpose of this study is to evaluate the clinical applicability of an enteral tube feeding formula containing fish oil and prebiotics in a critical care population.
Empirical implantation of the left ventricular lead is the prevailing practice in cardiac resynchronization therapy device implantation. The response rate to the therapy has been uniforml...
To compare the number of infants who discontinue from study formula due to formula intolerance as documented by the investigator. Hypothesize there will be no difference between formula g...