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Permissible Level (permissible + level)

Distribution by Scientific Domains

Chemistry	40%

Selected Abstracts

Effect of Decrease of Hydride-Induced Embrittlement in Nanocrystalline Titanium,

ADVANCED ENGINEERING MATERIALS, Issue 8 2010
M.A. Murzinova
Abstract The room-temperature impact toughness, strength and ductility of nanocrystalline (NC) and microcrystalline (MC) titanium with hydrogen content ranging from 0.1 to 16,at.-% (0.002 to 0.450,wt.-%) are studied. NC titanium has higher strength and lower sensitivity to hydride-induced brittle fracture than the MC material. In contrast to MC titanium, the elongation and impact toughness in the NC material does not decrease dramatically with increasing hydrogen content. Moreover, the fracture toughness in hydrogenated NC condition is found to be higher than that in MC titanium. This unusual result may be associated with the precipitation of equiaxial nanoscale hydrides in the interior of ,-grains in the NC material, while platelet hydrides are formed in MC titanium. One can expect that the risk of hydride-induced embrittlement is lower in NC than in MC titanium, making the NC material attractive for potential application under conditions that may cause hydrogen saturation above the permissible level for MC titanium. [source]

Assessment of aflatoxin M1 levels in selected dairy products in north-western Iran

INTERNATIONAL JOURNAL OF DAIRY TECHNOLOGY, Issue 2 2010
HAMID MOHAMADI
The purpose of this survey was to evaluate the natural occurrence and content of aflatoxin M1, AFM1, in dairy products marketed in Urmia. During September 2007, 40 samples of pasteurised milk, 40 samples of ultra high temperature-treated (UHT) milk, 40 samples of creamy cheese and 40 samples of Iranian Feta cheese were collected from different supermarkets in Urmia city. AFM1 contents were determined by the competitive enzyme-linked imunosorbent assay (ELISA) technique. All milk samples analysed showed a mean of AFM1 concentrations lower than the permissible level of 50 ng/kg in Iran (23.22 and 19.53 ng/kg in pasteurised milk and UHT milk respectively). The mean levels of AFM1 contamination were 43.31 ng/kg in Feta cheeses and 21.96 ng/kg in creamy cheeses. The potential risk of human exposure to aflatoxin M1 via consumption of milk and milk products is well known. Dairy products must therefore be evaluated for aflatoxin and kept free from fungal contamination as much as possible. [source]

Anticipation of Radiation Dose to the Conceptus from Occupational Exposure of Pregnant Staff During Fluoroscopically Guided Electrophysiological Procedures

JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 7 2005
JOHN DAMILAKIS Ph.D.
Introduction: A female employee working in the electrophysiology suite has the right to know potential radiation hazards to the unborn child before she is pregnant or before she decides to formally declare her pregnancy. Moreover, the employer of a declared pregnant worker must evaluate the work situation and ensure that the conceptus dose is kept below the maximum permissible level during the remaining gestation period. The aim of this study was to develop a method for conceptus dose anticipation and determination of maximum workload allowed for the pregnant employee who participates in fluoroscopically guided electrophysiological procedures. Methods and Results: A C-arm fluoroscopy system, an anthropomorphic phantom, and a radiation meter were used to obtain scattered air kerma dose rates separately for each of the three fluoroscopic projections typically used in the electrophysiology suite. Air kerma to conceptus dose conversion factors for all trimesters of gestation were calculated using Monte Carlo simulation. A formula is presented for the anticipation of the conceptus dose from occupational exposure of pregnant staff during fluoroscopically guided electrophysiological procedures. Normalized data are provided for conceptus dose estimation from occupational exposure of pregnant staff working in any electrophysiology laboratory. A methodology for estimation of maximum workload allowed for each month of the remaining gestation period of a worker who declared her pregnancy is proposed, which ensures that the regulatory dose limits are not exceeded. Conclusion: Data presented may be used for the implementation of a radiation protection program designed for pregnant staff working in an electrophysiological suite. [source]

BIODEGRADATION OF DISINFECTION BYPRODUCTS AS A POTENTIAL REMOVAL PROCESS DURING AQUIFER STORAGE RECOVERY,

JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION, Issue 4 2000
James E. Landmeyer
ABSTRACT: The biodegradation potential of two drinking water disinfection byproducts was investigated using aquifer materials obtained from approximately 100 and 200 meters below land surface in an aerobic aquifer system undergoing aquifer storage recovery of treated surface water. No significant biodegradation of a model trihalomethane compound, chloroform, was observed in aquifer microcosms under aerobic or anaerobic conditions. In contrast, between 16 and 27 percent mineralization of a radiolabeled model haloacetic acid compound, chloroacetic acid, was observed. These results indicate that although the potential for biodegradation of chloroacetic acid exists in deep aquifer systems, chloroform entrained within these aquifers or formed in situ will tend to persist. These results have important implications for water managers planning to meet anticipated lowered permissible levels of trihalomethanes in drinking water. [source]

Right-first-time production in batch dyeing of wool,,

COLORATION TECHNOLOGY, Issue 6 2001
U M Adamiak
Powder dyes exhibit even more pronounced sorption behaviour than fibres. The moisture content and weight of the dyes and yarns change according to the ambient relative humidity. In this study, the variations determined in dyehouse stores caused weight changes and subsequent dyeings showed differences of ,,E* and ,,L* beyond permissible levels. The detrimental influence on the ability to reach right-first-time level of acceptance substantially diminishes the profit margin. The consequence for computer colour-matching should be the integration of the moisture content of dyes and goods in the recipe calculation. From a technological viewpoint, however, it seems preferable to avoid any fluctuation in relative humidity where dyes and goods are stored. The costs incurred for investment in humidity control will pay in the long run and the factor of moisture content may be entirely negligible. [source]