Distribution of total bacteria and staphylococci in PM2.5, PM10 and total dust in the emission of two fattening pig houses/Verteilung von Gesamtbakterien und Staphylokokken in PM2,5, PM10 und Gesamtstaub in der Emission von zwei Mastschweineställen

Gefahrstoffe ◽  
2020 ◽  
Vol 80 (09) ◽  
pp. 344-348
Author(s):  
M. Clauß ◽  
S. Linke ◽  
A. C. Springorum
Keyword(s):  
Particle Size ◽  
Size Fraction ◽  
Airborne Bacteria ◽  
Dispersion Modelling ◽  
Particle Size Fraction ◽  
Collection System ◽  
Total Dust ◽  
Dust Distribution ◽  
Selective Collection ◽  
Total Bacteria

The particle size distribution of airborne bacterial conglomerates is an important factor in calculating possible spread distances of the bacteria over the air. Therefore, a size-selective collection system based on an emission impinger was developed to compare the distribution of total bacteria and staphylococci in particle fractions PM2.5, PM10 and total dust in the emission of two fattening pig stables. Mean emissions of 7.2 × 104 cfu/m³ total bacteria, 6.1 × 104 cfu/m³ staphylococci and 2.8 × 106 cells/m3 measured. About 30% of total bacteria and staphylococci were found in the PM2.5 particle size fraction and about 60% in PM10. The average dust distribution was 80% PM10 and 60% PM2.5. The results show that airborne bacteria from fattening pig units mainly occur on larger particles and do not correlate with dust fractions. The found conditions should be considered in future dispersion modelling.

scholarly journals Laser Diffraction as An Innovative Alternative to Standard Pipette Method for Determination of Soil Texture Classes in Central Europe

Water ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1232
Author(s):  
Dušan Igaz ◽  
Elena Aydin ◽  
Miroslava Šinkovičová ◽  
Vladimír Šimanský ◽  
Andrej Tall ◽  
...  
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Soil Texture ◽  
Polynomial Regression ◽  
Texture Classification ◽  
Size Fraction ◽  
Laser Diffraction ◽  
Classification Systems ◽  
Particle Size Fraction

The paper presents the comparison of soil particle size distribution determined by standard pipette method and laser diffraction. Based on the obtained results (542 soil samples from 271 sites located in the Nitra, Váh and Hron River basins), regression models were calculated to convert the results of the particle size distribution by laser diffraction to pipette method. Considering one of the most common soil texture classification systems used in Slovakia (according to Novák), the emphasis was placed on the determination accuracy of particle size fraction <0.01 mm. Analysette22 MicroTec plus and Mastersizer2000 devices were used for laser diffraction. Polynomial regression model resulted in the best approximation of measurements by laser diffraction to values obtained by pipette method. In the case of particle size fraction <0.01 mm, the differences between the measured values by pipette method and both laser analyzers ranged in average from 3% up to 9% and from 2% up to 11% in the case of Analysette22 and Mastersizer2000, respectively. After correction, the differences decreased to average 3.28% (Analysette22) and 2.24% (Mastersizer2000) in comparison with pipette method. After recalculation of the data, laser diffraction can be used alongside the sedimentation methods.

scholarly journals Temporal Variation of Radiocarbon Concentration in Airborne Particulate Matter in Tokyo

Radiocarbon ◽  
2004 ◽  
Vol 46 (1) ◽  
pp. 485-490 ◽  
Author(s):  
Ken Shibata ◽  
Michio Endo ◽  
Naomichi Yamamoto ◽  
Jun Yoshinaga ◽  
Yukio Yanagisawa ◽  
...  
Keyword(s):  
Particle Size ◽  
Particulate Matter ◽  
Size Fraction ◽  
Airborne Particulate Matter ◽  
Coarse Particles ◽  
Particle Size Fraction ◽  
Airborne Particulate ◽  
Carbonaceous Particles ◽  
Secondary Particles ◽  
Insight Into

The temporal radiocarbon variation (in terms of percent Modern Carbon: pMC) of size-fractionated airborne particulate matter (APM) collected in Tokyo between April 2002 and February 2003 was analyzed in order to get an insight into the sources of carbonaceous particles. Results indicated significant biogenic origins (approximately 40 pMC on average). In general, the seasonal and particle size variations in pMC were relatively small, with 2 exceptions: elevated pMC in coarse particles in April and October 2002, and relatively low pMC in the finest particle size fraction collected in August 2002. The former finding could be tentatively attributed to the abundance of coarse particles of biological origins, such as pollen; the latter might be due to an increased fraction of anthropogenic secondary particles.

scholarly journals Microstructure and Mechanical Properties of an Advanced Nickel-Based Superalloy in the as-HIP Form

2011 ◽  
Vol 278 ◽  
pp. 265-270 ◽  
Author(s):  
J.R. May ◽  
M.C. Hardy ◽  
M.R. Bache ◽  
David D. Kaylor
Keyword(s):  
Heat Treatment ◽  
Particle Size ◽  
Crack Growth ◽  
Powder Particle ◽  
Size Fraction ◽  
Fine Powder ◽  
Powder Particle Size ◽  
Particle Size Fraction ◽  
Coarse Powder ◽  
Nickel Based Superalloy

This study evaluates the suitability of as-hot isostatically pressed (HIP) RR1000 for non-critical applications in aero-engine components. RR1000, an advanced powder nickel-based superalloy, was developed for disc rotor components in aero-engines. For these critical applications, the consolidated alloy powder particles are extruded to break down carbide and oxide networks, known as prior particle boundaries (PPBs), and to refine the structure into a fine grain size for isothermal forging. In this study, hot isostatically pressed compacts, made from two different powder particle size fractions have been assessed following heat treatments below and above the gamma prime solvus temperature. A microstructural evaluation shows a greater degree of PPB decoration occurs in the finer powder particle size fraction. Following a super-solvus heat treatment these PPBs pin grain boundaries of the fine powder particle size compacts, whilst the reduction of PPB decoration in coarse powder particle compacts allows significant grain growth. Tensile test results of as-HIP RR1000 show, good yield strengths, ultimate tensile strengths and ductility, which are comparable with extruded and isothermal forged RR1000 disc material. Dwell crack propagation tests show that finer powder particle size compacts, which have received a sub-solvus heat treatment, give the highest crack growth rates; whilst the remaining material conditions show markedly improved crack growth resistance. In conclusion, as-HIP RR1000 demonstrates clear potential for use in non-critical applications, employing either powder particle size fraction used in this study subject to the appropriate solution heat treatment.

scholarly journals Grinding Kinetics Adjustment of Copper Ore Grinding in an Innovative Electromagnetic Mill

2018 ◽  
Vol 8 (8) ◽  
pp. 1322 ◽  
Author(s):  
Marta Wołosiewicz-Głąb ◽  
Paulina Pięta ◽  
Dariusz Foszcz ◽  
Szymon Ogonowski ◽  
Tomasz Niedoba
Keyword(s):  
Particle Size ◽  
Size Fraction ◽  
Processing Parameters ◽  
Relative Increase ◽  
Grinding Process ◽  
Particle Size Fraction ◽  
Copper Ore ◽  
Media Type ◽  
Grinding Media ◽  
Ultrafine Grinding

The paper presents a study on the effectiveness of the grinding process in an electromagnetic mill devoted to ultrafine grinding, and the influence of processing parameters on the mill’s performance. The research was focused on the optimization of the duration of the grinding process and selection of the grinding media type in order to obtain the highest relative increase of the selected particle size fraction. Copper ore with a particle size between 0–1 mm was used in the experiments. A model was created that determines the relationship between the processing time and efficiency of the grinding, and can be used for the optimization of the process. A comparison of the relative growth of particle size fractions in milling products was performed. The obtained milling efficiency results measured by the growth of the analyzed particle size fraction in the milling product confirmed that the best grinding media set includes a grinding medium with a diameter of 1 mm and a length of 10 mm.

Phthalate levels in Norwegian indoor air related to particle size fraction

2007 ◽  
Vol 9 (12) ◽  
pp. 1419 ◽  
Author(s):  
Kirsten Eline Rakkestad ◽  
Christian Jarle Dye ◽  
Karl Espen Yttri ◽  
Jørn Andreas Holme ◽  
Jan Kenneth Hongslo ◽  
...  
Keyword(s):  
Particle Size ◽  
Indoor Air ◽  
Size Fraction ◽  
Particle Size Fraction
Sign in / Sign up

Export Citation Format

Share Document