scholarly journals Levels of particulate matter in Western UAE desert and factors affecting their distribution

2013 ◽  
Author(s):  
F. Al Jallad ◽  
E. Al Katheeri ◽  
M. Al Omar
Keyword(s):  
Particulate Matter ◽  
Factors Affecting

scholarly journals The nylon bag technique in the determination of ruminal feed protein degradation

1983 ◽  
Vol 55 (1) ◽  
pp. 1-78 ◽  
Author(s):  
Jouko Setälä
Keyword(s):  
Particulate Matter ◽  
Pore Size ◽  
Control Sample ◽  
Sample Treatment ◽  
Sample Weight ◽  
Factors Affecting ◽  
Experimental Animals ◽  
Incubation Periods ◽  
Feed Protein

The investigation included experiments in which factors affecting the reliability of the nylon bag method were studied. The possibility of applying the feed protein degradabilities to practical feeding conditions was also examined. In the experiments concerning reliability, such factors as bag porosity, sample weight, sample treatment, washing procedure, diets, and differences between animals and incubation days were studied. The feed protein degradabilities were also determined by using as incubation periods the ruminal retention times for particulate matter of different feeds, evaluated as a function of DM intake/100 kg liveweight in different diets. A nylon bag, with a pore size of 40 µm and internal dimensions of 6 X 12 cm was selected for the degradability determinations. The sample weight used in incubations was 57 —60  mg DM/cm2. In the determination of feed protein degradability, when sheep are used as experimental animals, it is recommended that for routine determinations only one animal be used, analyzing the contents of two bags for each incubation period during two successive days. A control sample of which degradability is determined in advance in many sheep, should be used in all incubations in order to control the digestive processes in the rumen of the experimental sheep. The actual degradabilities analyzed by the bag method are applicable in practise, if they are determined using animals at similar feeding levels and on diets similar to those prevailing under the conditions in which the degradabilities are going to be used.

scholarly journals Factors affecting aerosol size distribution during various dental procedures

2021 ◽  
Author(s):  
Shruti Choudhary ◽  
Michael J Durkin ◽  
Daniel C Stoeckel ◽  
Heidi M Steinkamp ◽  
Martin H Thornhill ◽  
...  
Keyword(s):  
Particulate Matter ◽  
High Speed ◽  
High Volume ◽  
Routine Care ◽  
Mitigation Strategies ◽  
Aerosol Size Distribution ◽  
Dental Clinic ◽  
Factors Affecting ◽  
Dental Procedures ◽  
The Impact

Objectives: To determine the impact of various aerosol mitigation interventions and establish duration of aerosol persistence in a variety of dental clinic configurations. Methods: We performed aerosol measurement studies in endodontic, orthodontic, periodontic, pediatric, and general dentistry clinics. We used an optical aerosol spectrometer and wearable particulate matter sensors to measure real-time aerosol concentration from the vantage point of the dentist during routine care in a variety of clinic configurations (e.g, open bay, single room, partitioned operatories). We compared the impact of aerosol mitigation strategies [ventilation and high-volume evacuation (HVE)] and prevalence of particulate matter in the dental clinic environment before, during and after high-speed drilling, slow speed drilling and ultrasonic scaling procedures. Results: Conical and ISOVAC HVE were superior to standard tip evacuation for aerosol-generating procedures. When aerosols were detected in the environment, they were rapidly dispersed within minutes of completing the aerosol-generating procedure. Few aerosols were detected in dental clinics, regardless of configuration, when conical and ISOVAC HVE were used. Conclusions: Dentists should consider using conical or ISOVAC HVE rather than standard tip evacuators to reduce aerosols generated during routine clinical practice. Furthermore, when such effective aerosol mitigation strategies are employed, dentists need not leave dental chairs fallow between patients as aerosols are rapidly dispersed. Clinical Significance: ISOVAC HVE is highly effective in reducing aerosol emissions. With adequate ventilation and HVE use, dental fallow time can be reduced to 5 minutes.

Personal PM10 exposure in asthmatic adults in Padova, Italy: seasonal variability and factors affecting individual concentrations of particulate matter

2009 ◽  
Vol 212 (6) ◽  
pp. 626-636 ◽  
Author(s):  
Maria Luisa Scapellato ◽  
Cristina Canova ◽  
Andrea de Simone ◽  
Mariella Carrieri ◽  
Piero Maestrelli ◽  
...  
Keyword(s):  
Particulate Matter ◽  
Seasonal Variability ◽  
Factors Affecting ◽  
Pm10 Exposure

Factors affecting the digestion of oesophageal fistula samples and hay samples in nylon bags in the rumen of cattle

1978 ◽  
Vol 90 (1) ◽  
pp. 193-204 ◽  
Author(s):  
M. J. Playne ◽  
W. Khumnualthong ◽  
M. G. Echevarria
Keyword(s):  
Particulate Matter ◽  
Sample Size ◽  
Cell Walls ◽  
Nutritional Value ◽  
Small Sample ◽  
Factors Affecting ◽  
Heteropogon Contortus ◽  
Second Stage ◽  
Method Of Placement ◽  
Feed Samples

SUMMARYFactors affecting the nylon-bag technique, for examination of digestion in the rumen of extrusa and hay samples of low nutritional value, were studied. Effects of: the method of placement of bags in the rumen; saliva in extrusa; drying and milling techniques; a second-stage digestion with acid-pepsin solution; sample size; and losses of particulate matter through bag cloth were studied. Digestion of dry matter (d.m.) and cell walls after 12, 24, 48, 72 and 168 h in the rumen were used to indicate treatment effects.Attaching bags with nylon cord to a weight was a better method than enclosing them in perforated jars in the rumen which restricted digestion. Drying technique had little effect on digestion, although frozen extrusa was digested more than oven-dried feed, especially in samples of Heteropogon contortus. Chewing of forage was sufficient to obtain maximum rates of digestion. Milling extrusa through 1 or 2 mm screens did not increase digestion. An extra period of digestion in acid-pepsin solution increased digestion of feed samples more than that of extrusa, but the effects were small. It reduced between-bag variation slightly, but did not alter the significance of differences between treatments. The effect of sample size on digestion was small. Sample weight (3, 6 and 9 g) was kept proportional (42 mg/cm2) to bag cloth area.Digestion of d.m. after 24 h reflected digestion of cell walls. Digestion of cell walls was faster in grasses than in legumes. The higher digestibility of legumes was due to solubilization within 24 h of the greater amounts of cell contents found in legumes. Cell contents were only partially solubilized, and up to 10 g per 100 g original d.m. were not removed. Losses of particulate matter averaged 4·6% (range 0·5–10·6%). Losses were high when samples were finely milled (1 mm screen) but varied between species. Pore aperture of cloth was 25 μm. Methods for determining loss and correction of digestion data for such losses are given.

Meteorological Factors Affecting Particulate Air Pollution of a City

1961 ◽  
Vol 42 (8) ◽  
pp. 556-560 ◽  
Author(s):  
R. R. Dickson
Keyword(s):  
Air Pollution ◽  
Particulate Matter ◽  
Meteorological Factors ◽  
Absolute Error ◽  
Graphical Analysis ◽  
Factors Affecting ◽  
Particulate Air Pollution ◽  
Day Of The Week ◽  
Matter Concentration ◽  
Pollution Concentrations

Due to its utility in handling joint functions, the method of coaxial graphical correlation is used to relate particulate air pollution at Nashville, Tennessee to various meteorological factors. The derived relationship applied to test data yielded an average absolute error of 38.3 micrograms per cubic meter and root-mean-square error of 59.3; these results are clearly superior to a climatological control forecast using seasonal average concentrations. Graphical analysis and supporting correlation-ratio computations suggest that small amounts of precipitation may be very effective in cleansing particulate matter from the atmosphere, rendering further precipitation of little consequence. The analysis emphasizes the importance of wind direction in governing air-pollution concentrations at a point, suggesting that point measurement of particulate concentrations may have little representativeness when applied to an area the size of a city. Particulate-matter concentration is found significantly correlated with day of the week (weekday-weekend groupings), offering an avenue for improvement of results.

scholarly journals Dispersion of Nitrogen Dioxide and Particulate Matter Concentrations in Street Canyons and Open Landscape in Urban Mysore

2020 ◽  
Vol 7 (3) ◽  
pp. 36-43
Author(s):  
Prabhakaran Nataraj ◽  
Azis Kemal Fauzie ◽  
P N Sandhya Rani ◽  
G V Venkataramana
Keyword(s):  
Particulate Matter ◽  
Wind Speed ◽  
Nitrogen Dioxide ◽  
Meteorological Data ◽  
Tall Buildings ◽  
Urban Spaces ◽  
Street Canyons ◽  
Factors Affecting ◽  
Pm10 And Pm2.5 ◽  
Different Types

The variation in nitrogen dioxide (NO2), particulate matter (PM10 and PM2.5) concentrations and meteorological data were analyzed at different types of urban spaces in Mysore consisting of four street canyons and one open landscape sites. The NO2 and PM levels were measured using portable monitoring device and respirable dust sampler, respectively. The maximum NO2 concentration was found at the intersection of both street canyons and open landscape, either in the morning (70-160 µg/m3) or evening (20-60 µg/m3). Result found that concentration of NO2 in street canyons was significantly higher than in open landscape sites (p < 0.001). The ambient NO2 levels were also found lower in the cross roads compared to such in the main roads. The high number of vehicles passing through the roads accounts for the higher NO2 concentration as we found significant positive correlation between traffic volume and NO2, SPM, PM10 and PM2.5 concentrations, either in the street canyon and open landscape sites. Furthermore, a negative association has been observed between both SPM and NO2 levels and the wind speed (p = 0.002 and p < 0.05 respectively). The factors affecting the different dispersion characteristics of air pollutants were found to be the wind speed, vehicular traffic, and site landscape where congested with high number of tall buildings.

Factors affecting the formation of white particulate matter in red blood cell components

Transfusion ◽  
2005 ◽  
Vol 45 (7) ◽  
pp. 1127-1132 ◽  
Author(s):  
Hina D. Patel ◽  
Karen M. Byrne ◽  
McDonald Horne ◽  
Susan F. Leitman ◽  
David F. Stroncek
Keyword(s):  
Particulate Matter ◽  
Blood Cell ◽  
Red Blood Cell ◽  
Factors Affecting ◽  
Cell Components
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