			Home About us Contact

Stainless Steel Tube (stainless + steel_tube)

Distribution by Scientific Domains

Chemistry	50%

Selected Abstracts

Macro- and Micro-Purge Soil-Gas Sampling Methods for the Collection of Contaminant Vapors

GROUND WATER MONITORING & REMEDIATION, Issue 1 2009
Brian A. Schumacher
Purging influence on soil-gas concentrations for volatile organic compounds (VOCs), as affected by sampling tube inner diameter and sampling depth (i.e., system volume) for temporary probes in fine-grained soils, was evaluated at three different field sites. A macro-purge sampling system consisted of a standard, hollow, 3.2-cm outer diameter (OD) drive probe with a retractable sampling point attached to an appropriate length of 0.48-cm inner diameter (ID) Teflon® tubing. The macro-purge sampling system had a purge system volume of 24.5 mL at a 1-m depth. In contrast, the micro-purge sampling systems were slightly different between the field sites and consisted of a 1.27-cm OD drive rod with a 0.10-cm ID stainless steel tube or a 3.2-cm OD drive rod with a 0.0254-cm inner diameter stainless steel tubing resulting in purge system volumes of 1.2 and 7.05 mL at 1-m depths, respectively. At each site and location within the site, with a few exceptions, the same contaminants were identified in the same relative order of abundances indicating the sampling of the same general soil atmosphere. However, marked differences in VOC concentrations were identified between the sampling systems, with micro-purge samples having up to 27 times greater concentrations than their corresponding macro-purge samples. The higher concentrations are the result of a minimal disturbance of the ambient soil atmosphere during purging. The minimal soil-gas atmospheric disturbance of the micro-purge sampling system allowed for the collection of a sample that is more representative of the soil atmosphere surrounding the sampling point. That is, a sample that does not contain an atmosphere that has migrated from distance through the geologic material or from the surface in response to the vacuum induced during purging soil-gas concentrations. It is thus recommended that when soil-gas sampling is conducted using temporary probes in fine-grained soils, the sampling system use the smallest practical ID soil-gas tubing and minimize purge volume to obtain the soil-gas sample with minimal risk of leakage so that proper decisions, based on more representative soil-gas concentrations, about the site can be made. [source]

A cylindrical capacitor ionization source: droplet generation and controlled charge reduction for mass spectrometry

RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 6 2001
Daniel D. Ebeling
A cylindrical capacitor ionization source was used in conjunction with corona discharge charge reduction for generation of singly charged ions for mass spectrometric analysis. The source consists of a fused-silica capillary threaded with a platinum wire and placed inside a stainless steel tube. Application of an electric potential to the wire results in the production of a linear stream of charged droplets when an aqueous solution is pumped through the capillary. Subsequent solvent evaporation yields ions, providing a continuous ion source for mass spectrometry. Passage of the ions through a corona discharge charge reduction chamber permits reduction of the charge state to predominantly singly charged species, facilitating analysis of DNA and protein mixtures. The change from production of multiply charged ions to production of singly charged ions is extremely simple, requiring only modulation of the voltage applied to the corona discharge electrode. A simple technique for construction of the ionization source is reported. Copyright © 2001 John Wiley & Sons, Ltd. [source]

Minimum Wetting Rates for Falling Films on Stainless Steel

ASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 1-2 2006
K. R. Morison
The minimum wetting rate is defined as the minimum mass flowrate per unit circumference that is required to maintain of complete falling film of liquid on a surface. In this work minimum wetting rates in a 48 mm i.d. stainless steel tube were determined jor water, 50% sucrose solution, and reconstituted skim milk under isothermal and heat transfer conditions. It was found that initial distribution of the liquid at the top of the tube was critically important. The minimum wetting rates under isothermal and heat transfer conditions ranged from 0.22 kg m,1 s,1 for 50% sucrose at 20% to 0.12 kg m,1 s,1 for water az 70°C. Nearly all rates decreased with temperature. Equations in the literature did not accurately predict the results obtained. [source]

Bioreactor Coupled with Electromagnetic Field Generator: Effects of Extremely Low Frequency Electromagnetic Fields on Ethanol Production by Saccharomycescerevisiae

BIOTECHNOLOGY PROGRESS, Issue 5 2007
Victor H. Perez
The effect of extremely low frequency (ELF) magnetic fields on ethanol production by Saccharomyces cerevisiae using sugar cane molasses was studied during batch fermentation. The cellular suspension from the fermentor was externally recycled through a stainless steel tube inserted in two magnetic field generators, and consequently, the ethanol production was intensified. Two magnetic field generators were coupled to the bioreactor, which were operated conveniently in simple or combined ways. Therefore, the recycle velocity and intensity of the magnetic field varied in a range of 0.6,1.4 m s,1 and 5,20 mT, respectively. However, under the best conditions with the magnetic field treatment (0.9,1.2 m s,1 and 20 mT plus solenoid), the overall volumetric ethanol productivity was approximately 17% higher than in the control experiment. These results made it possible to verify the effectiveness of the dynamic magnetic treatment since the fermentations with magnetic treatment reached their final stage in less time, i.e., approximately 2 h earlier, when compared with the control experiment. [source]