scholarly journals Effect of Ammonium Nitrate on Nanoparticle Size Reduction

2008 ◽  
Vol 2008 ◽  
pp. 1-4 ◽  
Author(s):  
Kalyana C. Pingali ◽  
Shuguang Deng ◽  
David A. Rockstraw
Keyword(s):  
Ammonium Nitrate ◽  
Metallic Nanoparticles ◽  
Particle Diameter ◽  
Feed Solution ◽  
Pyrolysis Process ◽  
Foaming Agent ◽  
Aerosol Droplet ◽  
Order Of Magnitude ◽  
Spray Pyrolysis Process ◽  
20 Nm

Ammonium nitrate was added to the spraying solution as a foaming agent to reduce the particle size of nanoparticles synthesized in the spray-pyrolysis process. Ammonium nitrate was effective in breaking the aerosol droplet size and generating nanoparticles that were of approximately one order-of-magnitude (from 200 to 20 nm) smaller diameter than those created in the absence of ammonium nitrate in the feed solution. This technique makes it possible to control the particle diameter of metallic nanoparticles below 20 nm.

scholarly journals A Comparative Evaluation of Nanohydroxyapatite-Enriched Hydrogen Peroxide Home Bleaching System on Color, Hardness and Microstructure of Dental Enamel

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3072
Author(s):  
Riccardo Monterubbianesi ◽  
Vincenzo Tosco ◽  
Tiziano Bellezze ◽  
Giampaolo Giuliani ◽  
Mutlu Özcan ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Particle Diameter ◽  
Dental Enamel ◽  
Sem Analysis ◽  
Control Group ◽  
Average Particle ◽  
Color Analysis ◽  
Enamel Microstructure ◽  
Prismatic Structure ◽  
20 Nm

This study aimed to evaluate two hydrogen peroxide (HP)-based at-home bleaching systems in order to analyze whether nano-hydroxyapatite (nHA) addition may represent a reliable and safe solution for tooth whitening without altering dental microstructure and hardness. Human third molars (N = 15) were treated with two bleaching agents, one containing 6%HP (6HP) and the other 6% HP nHA-enriched (6HP-nHA) with average particle diameter ranging from 5–20 nm. Their effects on enamel were assessed using a spectrophotometer, Vickers microhardness (VMH) test and Scanning Electron Microscopy (SEM), comparing the treated groups with the non-treated control group (CTR). Color analysis revealed improvement in whiteness in both groups compared to CTR. VMH test results showed no differences among the groups. SEM analysis highlighted no evident changes in the enamel microstructure of tested groups compared to CTR. At high magnification, in 6HP group, a slight increase in irregularities of enamel surface morphology was observed, while 6HP-nHA group displayed removal of the aprismatic layer but preservation of the intact prismatic structure. These results suggest that the 6HP-nHA agent may be recommended to provide reliable whitening treatment, without damaging the enamel micromorphology and hardness.

Deposition and characterization of La2Ti2O7 thin films via spray pyrolysis process

2007 ◽  
Vol 253 (10) ◽  
pp. 4560-4565 ◽  
Author(s):  
D.S. Todorovsky ◽  
R.V. Todorovska ◽  
M.M. Milanova ◽  
D.G. Kovacheva
Keyword(s):  
Thin Films ◽  
Spray Pyrolysis ◽  
Pyrolysis Process ◽  
Spray Pyrolysis Process

scholarly journals A method for detecting the presence of organic fraction in nucleation mode sized particles

2005 ◽  
Vol 5 (12) ◽  
pp. 3277-3287 ◽  
Author(s):  
P. Vaattovaara ◽  
M. Räsänen ◽  
T. Kühn ◽  
J. Joutsensaari ◽  
A. Laaksonen
Keyword(s):  
Sulfuric Acid ◽  
Field Experiments ◽  
Inorganic Compounds ◽  
Particle Diameter ◽  
Ethanol Vapor ◽  
Organic Fraction ◽  
Saturation Ratio ◽  
Nucleation Mode ◽  
Atmospheric Nucleation ◽  
20 Nm

Abstract. New particle formation and growth has a very important role in many climate processes. However, the overall knowlegde of the chemical composition of atmospheric nucleation mode (particle diameter, d<20 nm) and the lower end of Aitken mode particles (d≤50 nm) is still insufficient. In this work, we have applied the UFO-TDMA (ultrafine organic tandem differential mobility analyzer) method to shed light on the presence of an organic fraction in the nucleation mode size class in different atmospheric environments. The basic principle of the organic fraction detection is based on our laboratory UFO-TDMA measurements with organic and inorganic compounds. Our laboratory measurements indicate that the usefulness of the UFO-TDMA in the field experiments would arise especially from the fact that atmospherically the most relevant inorganic compounds do not grow in subsaturated ethanol vapor, when particle size is 10 nm in diameter and saturation ratio is about 86% or below it. Furthermore, internally mixed particles composed of ammonium bisulfate and sulfuric acid with sulfuric acid mass fraction ≤33% show no growth at 85% saturation ratio. In contrast, 10 nm particles composed of various oxidized organic compounds of atmospheric relevance are able to grow in those conditions. These discoveries indicate that it is possible to detect the presence of organics in atmospheric nucleation mode sized particles using the UFO-TDMA method. In the future, the UFO-TDMA is expected to be an important aid to describe the composition of atmospheric newly-formed particles.

Microstructural properties of ZnO:Sn thin films deposited by intermittent spray pyrolysis process

2009 ◽  
Vol 21 (2) ◽  
pp. 179-184 ◽  
Author(s):  
F. Kadi Allah ◽  
L. Cattin ◽  
M. Morsli ◽  
A. Khelil ◽  
N. Langlois ◽  
...  
Keyword(s):  
Thin Films ◽  
Spray Pyrolysis ◽  
Microstructural Properties ◽  
Pyrolysis Process ◽  
Spray Pyrolysis Process

Properties of NiO thin films deposited by intermittent spray pyrolysis process

2007 ◽  
Vol 253 (9) ◽  
pp. 4330-4334 ◽  
Author(s):  
B.A. Reguig ◽  
A. Khelil ◽  
L. Cattin ◽  
M. Morsli ◽  
J.C. Bernède
Keyword(s):  
Thin Films ◽  
Spray Pyrolysis ◽  
Pyrolysis Process ◽  
Spray Pyrolysis Process

scholarly journals Summertime observations of ultrafine particles and cloud condensation nuclei from the boundary layer to the free troposphere in the Arctic

2016 ◽  
Author(s):  
Julia Burkart ◽  
Megan D. Willis ◽  
Heiko Bozem ◽  
Jennie L. Thomas ◽  
Kathy Law ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Ultrafine Particles ◽  
Cloud Condensation Nuclei ◽  
Particle Diameter ◽  
Open Ocean ◽  
The Arctic ◽  
Condensation Nuclei ◽  
Aerosol Composition ◽  
Low Level ◽  
20 Nm

Abstract. The Arctic is extremely sensitive to climate change. Shrinking sea ice extent increases the area covered by open ocean during Arctic summer, which impacts the surface albedo and aerosol and cloud properties among many things. In this context extensive aerosol measurements (aerosol composition, particle number and size, cloud condensation nuclei, and trace gases) were made during 11 flights of the NETCARE July, 2014 airborne campaign conducted from Resolute Bay, Nunavut (74N, 94W). Flights routinely included vertical profiles from about 60 to 3000 m a.g.l. as well as several low-level horizontal transects over open ocean, fast ice, melt ponds, and polynyas. Here we discuss the vertical distribution of ultrafine particles (UFP, particle diameter, dp: 5–20 nm), size distributions of larger particles (dp: 20 nm to 1 μm), and cloud condensation nuclei (CCN, supersaturation = 0.6 %) in relation to meteorological conditions and underlying surfaces. UFPs were observed predominantly within the boundary layer, where concentrations were often several hundreds to a few thousand particles per cubic centimeter. Occasionally, particle concentrations below 10 cm−3 were found. The highest UFP concentrations were observed above open ocean and at the top of low-level clouds, whereas numbers over ice-covered regions were substantially lower. Overall, UFP formation events were frequent in a clean boundary layer with a low condensation sink. In a few cases this ultrafine mode extended to sizes larger than 40 nm, suggesting that these UFP can grow into a size range where they can impact clouds and therefore climate.

Three-dimensionally ordered mesoporous multicomponent (Ni, Mo) metal oxide/N-doped carbon composite with superior Li-ion storage performance

Nanoscale ◽  
2018 ◽  
Vol 10 (39) ◽  
pp. 18734-18741 ◽  
Author(s):  
Se Hwan Oh ◽  
Jin Koo Kim ◽  
Yun Chan Kang ◽  
Jung Sang Cho
Keyword(s):  
Metal Oxides ◽  
Preparation Method ◽  
Carbon Composite ◽  
Pyrolysis Process ◽  
Storage Performance ◽  
Simple Preparation ◽  
Ordered Mesoporous ◽  
Ion Storage ◽  
Li Ion ◽  
Spray Pyrolysis Process

A simple preparation method of mesoporous multicomponent metal oxides containing Ni and Mo components with N-doped carbon by spray pyrolysis process is introduced.

scholarly journals Long-Term Characterization of Submicron Atmospheric Particles in an Urban Background Site in Southern Italy

Atmosphere ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 334 ◽  
Author(s):  
Adelaide Dinoi ◽  
Marianna Conte ◽  
Fabio M. Grasso ◽  
Daniele Contini
Keyword(s):  
Particle Number ◽  
Meteorological Parameters ◽  
Particle Diameter ◽  
Number Concentration ◽  
Total Particle Number ◽  
Total Particle ◽  
Late Evening ◽  
20 Nm

Continuous measurements of particle number size distributions in the size range from 10 nm to 800 nm were performed from 2015 to 2019 at the ECO Environmental-Climate Observatory of Lecce (Global Atmosphere Watch Programme/Aerosol, Clouds and Trace Gases Research Infrastructure (GAW/ACTRIS) regional station). The main objectives of this work were to investigate the daily, weekly and seasonal trends of particle number concentrations and their dependence on meteorological parameters gathering information on potential sources. The highest total number concentrations were observed during autumn-winter with average values nearly twice as high as in summer. More than 52% of total particle number concentration consisted of Aitken mode (20 nm < particle diameter (Dp) < 100 nm) particles followed by accumulation (100 nm < Dp < 800 nm) and nucleation (10 nm < Dp < 20 nm) modes representing, respectively, 27% and 21% of particles. The total number concentration was usually significantly higher during workdays than during weekends/holidays in all years, showing a trend likely correlated with local traffic activities. The number concentration of each particle mode showed a characteristic daily variation that was different in cold and warm seasons. The highest concentrations of the Aitken and accumulation particle mode were observed in the morning and the late evening, during typical rush hour traffic times, highlighting that the two-particle size ranges are related, although there was significant variation in the number concentrations. The peak in the number concentrations of the nucleation mode observed in the midday of spring and summer can be attributed to the intensive formation of new particles from gaseous precursors. Based on Pearson coefficients between particle number concentrations and meteorological parameters, temperature, and wind speed had significant negative relationships with the Aitken and accumulation particle number concentrations, whereas relative humidity was positively correlated. No significant correlations were found for the nucleation particle number concentrations.

Sign in / Sign up

Export Citation Format

Share Document