scholarly journals Analysis of granulometric dust accumulating in supply and exhaust ventilation filters

2018 ◽  
Vol 44 ◽  
pp. 00030
Author(s):  
Bogdan Derbiszewski ◽  
Anna Kurek
Keyword(s):  
Diffraction Theory ◽  
Particle Size Analysis ◽  
City Centre ◽  
Size Analysis ◽  
Exhaust Ventilation ◽  
Air Supply ◽  
Air Handling Units ◽  
Different Seasons ◽  
Particle Sizer ◽  
The City

The research aim was to analyse and compare the composition of granulometric dust which accumulates in air filters located in central air handling units supporting the production rooms and at the same time the degree and a kind of contamination fraction of atmospheric air in a part of Wrocław situated outside the city centre. Samples were taken in different seasons of the year, such as March and October. The size of pollution particles extracted from ventilation filters was measured with the use of ANALYSETTE 22MicroTec plus laser particle sizer produced by FRITSCH. The results of measurements were generated with MaScontrol software for particle size analysis. In computing research results, the Fraunhofer diffraction theory was used. The comparison of the examined air particles’ size in an air supply canal allowed to determine the outside air dust size in Szczepin district on Długa street in Wrocław. Moreover, the influence of the year season on the size of contaminants accumulating in filters was also determined in the course of research works.

Analysis of the Incorporation of Scheelite Residue in Kaolinitic Clay of Boa Saúde-RN

2012 ◽  
Vol 727-728 ◽  
pp. 844-849 ◽  
Author(s):  
Tércio G. Machado ◽  
Uilame Umbelino Gomes ◽  
Flanelson M. Monteiro ◽  
Samara M. Valcacer ◽  
Gilson G. da Silva
Keyword(s):  
Raw Materials ◽  
Particle Size Analysis ◽  
Northeastern Brazil ◽  
Size Analysis ◽  
Bending Tests ◽  
Materials Used ◽  
Kaolinitic Clay ◽  
The City ◽  
Mineral Waste

The scheelite occurs mainly in northeastern Brazil, with highest abundance in the states of Rio Grande do Norte and Paraíba - Scheelite Seridó Province. Mining is considered an activity that provides a high environmental degradation due to the large amount of minerals and waste involved. Most mining companies have no technologies or processes that allow the recycling of mineral waste generated. The aim of this study is to evaluate the influence of different percentages of reject on the mechanical properties of scheelite and aesthetic (staining of the final product after firing) of the clay of the city of Boa Saúde - RN. The raw materials used were characterized by XRD, XRF and particle size analysis. Assay was performed by water absorption, linear retraction and bending tests on three points for the characterization of the final product. The raw materials used were from the city of Currais Novos-RN.

Phase and Particle Size Analysis of SnO2 Nanomaterials

2015 ◽  
Vol 1109 ◽  
pp. 314-318
Author(s):  
Nor Diyana Abdul Aziz ◽  
Kelimah Elong ◽  
Norlida Kamarulzaman
Keyword(s):  
Particle Size ◽  
Particle Size Analysis ◽  
Annealed Sample ◽  
Degree Of Crystallinity ◽  
Size Analysis ◽  
Size Distributions ◽  
X Ray Diffraction ◽  
Particle Size Distributions ◽  
X Ray ◽  
Particle Sizer

Tin Oxide (SnO2) is a metal oxide which has many applications in industry. In this study, SnO2 powders were synthesized by a self-propagating combustion (SPC) method. The product was annealed at 800 °C for 12 and 24 h before characterizing with X-Ray Diffraction (XRD) for phase studies. X-Ray Diffraction results showed that both samples are pure of tetragonal structure with space group P42/mnm. The sample annealed at a longer period, that is, 24 h, shows a higher degree of crystallinity compared to the 12 h annealed sample. It also shows a smaller full width at half maximum (FWHM), indicating larger crystallite size for the 24 h annealed sample. The particle size analysis reveals that there are two groups of particle size distributions for both samples. SEM results give values that are different from the particle sizer results due to the different nature of the measurement methods.

scholarly journals Spatial extension of nucleating air masses in the Carpathian Basin

2014 ◽  
Vol 14 (16) ◽  
pp. 8841-8848 ◽  
Author(s):  
Z. Németh ◽  
I. Salma
Keyword(s):  
Particle Growth ◽  
Middle Part ◽  
Carpathian Basin ◽  
City Centre ◽  
Southeastern Part ◽  
Air Masses ◽  
Contour Plots ◽  
Time Parameters ◽  
Particle Sizer ◽  
The City

Abstract. Particle number size distributions were measured by differential mobility particle sizer in the diameter range of 6–1000 nm in the near-city background and city centre of Budapest continuously for two years. The city is situated in the middle part of the Carpathian Basin, which is a topographically discrete unit in the southeastern part of central Europe. Yearly mean nucleation frequencies and uncertainties for the near-city background and city centre were (28 + 6/−4) % and (27 + 9/−4) %, respectively. The total numbers of days with continuous and uninterrupted growth process were 43 and 31, respectively. These events and their properties were utilised to investigate the spatial scale of the nucleation in the basin, and whether there are any specific trajectories for the nucleating air masses. Local wind speed and direction data indicated that there seem to be differences between the nucleation and growth intervals and non-nucleation days. For further analysis, backward trajectories were generated by a simple air parcel trajectory model. Start and end time parameters of the nucleation and an end time parameter of the particle growth were derived by a standardised procedure based on examining the channel contents of the contour plots. These parameters were used to specify a segment on each backward trajectory that is associated with the nucleating air mass. The results indicated that regional nucleation happened in the continental boundary layer mostly in the Carpathian Basin but that the most distant trajectories originated outside of the basin. The nucleating air masses were predominantly associated with NW and SE geographical sectors, and some of them were also related to larger forested territories. The results also emphasised indirectly that the regional new particle formation and growth phenomena observable at the fixed location often expand to the bulk of the Carpathian Basin.

Particle Size Study of Smectite Clays from the City of Pedra Lavrada-PB

2014 ◽  
Vol 775-776 ◽  
pp. 377-382
Author(s):  
Mirtys Allamana Ferreira Cardoso ◽  
Alexsandra Cristina Chaves ◽  
M.M. Dantas ◽  
Isabelle Albuquerque da Silva ◽  
I.D.S. Pereira ◽  
...  
Keyword(s):  
Particle Size ◽  
Particle Size Analysis ◽  
Size Analysis ◽  
Drilling Fluids ◽  
Particle Sizes ◽  
Smectite Clays ◽  
Significant Difference ◽  
Water Based ◽  
The City

The state of Paraíba disposes of one of the largest deposits of smectites in the country. However, these smectites present in their composition elevated contents of accessory minerals, especially quartz. For these clays to become viable to determine technological use it is necessary the elimination of part of these minerals. The particle size analysis of a soil consists in the determination of the size of the particles that constitute it and their distribution in certain intervals. This work aims to study smectite clays from the city of Pedra Lavrada-PB, through the particle size analyses, for the use in water based drilling fluids. The determination of particle size was made by sieving and laser granulometer. Apparent and plastic viscosities were measured from the samples. The clays were left at rest before the test for periods of 7 and 28 days, with and without deflocculant. It was verified that there was no significant difference in the particle sizes in relation to the resting time of the samples.

scholarly journals Approaching environmental human thermophysiological thresholds for the case of Ankara, Turkey

2020 ◽  
Vol 143 (1-2) ◽  
pp. 533-555
Author(s):  
A. Santos Nouri ◽  
Y. Afacan ◽  
O. Çalışkan ◽  
Tzu-Ping Lin ◽  
A. Matzarakis
Keyword(s):  
Heat Stress ◽  
Physiological Stress ◽  
Balance Model ◽  
City Centre ◽  
Climate Index ◽  
Thermal Climate ◽  
Different Seasons ◽  
The City ◽  
Extreme Heat Stress ◽  
Cold Extremes

AbstractThe disclosed study undertook a ‘human centred-approach’ that ascertained and categorised environmental human thermophysiological risk factors by relating them to the human biometeorological system through the use of three widely utilised energy balance model (EBM) indices, the physiologically equivalent temperature (PET), the modified PET, and the universal thermal climate index (UTCI). The disclosed assessment was carried out over the past decade (i.e., 2010–2019) with a 3-h temporal resolution for the case of Ankara through two WMO meteorological stations to compare both local urban and peri-urban environmental conditions. The study recognised extreme annual variability of human physiological stress (PS) during the different seasons as a result of the biometeorological processing of the singular variables, which in the case of average PET for both stations, varied by up to 75 °C between the winter and summer for the same annual dataset (2012). In addition, all EBMs indicated higher heat stress within the city centre that were conducive of both urban extreme heatwaves and very hot days during the summer months, with extreme heat stress levels lasting for longer than a week with PET values reaching a maximum of 48 °C. Similar cold extremes were found for the winter months, with PET values reaching − 30 °C, and average PS levels varying lower in the case of the peri-urban station.Graphical abstract

Acyclovir Loaded Solid Lipid Nanoparticle Based Cream: A Novel Drug Delivery System

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
EL- Assal I. A. ◽  
Retnowati .
Keyword(s):  
Drug Delivery ◽  
Drug Release ◽  
Antiviral Agent ◽  
Study Drug ◽  
Particle Size Analysis ◽  
Stability Study ◽  
Size Analysis ◽  
Solid Lipid ◽  
Dermal Delivery

Objective of the present investigation was enthused by the possibility to develop solid lipid nanoparticles (SLNs) of hydrophilic drug acyclovir. Also study vitro and vivo drug delivery. Methods: Drug loaded SLNs (ACV-SLNs) were prepared by high pressure homogenization of aqueous surfactant solutions containing the drug-loaded lipids in the melted or in the solid state with formula optimization study (Different lipid concentration, drug loaded, homogenization / stirring speed and compritol 888ATO: drug ratio). ACV - SLN incorporated in cream base. The pH was evaluated and rheological study. Drug release was evaluated and compared with simple cream- drug, ACV – SLN with compritol 888ATO and marketed cream. The potential of SLN as the carrier for dermal delivery was studied. Results: Particle size analysis of SLNs prove small, smooth, spherical shape particle ranged from 150 to 200 nm for unloaded and from 330 to 444 nm for ACV loaded particles. The EE% for optimal formula is 72% with suitable pH for skin application. Rheological behavior is shear thinning and thixotropic. Release study proved controlled drug release for SLNs especially in formula containing compritol88 ATO. Stability study emphasized an insignificant change in SLNs properties over 6 month. In-vivo study showed significantly higher accumulation of ACV in stratum corneum, dermal layer, and receptor compartment compared with blank skin. Conclusion: AVC-loaded SLNs might be beneficial in controlling drug release, stable and improving dermal delivery of antiviral agent(s).

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