scholarly journals Au-nanoparticle synthesis via ultrasonic spray pyrolysis with a separate evaporation zone

2015 ◽  
Vol 49 (5) ◽  
pp. 791-796 ◽  
Author(s):  
Peter Majerič ◽  
Bernd Friedrich ◽  
Rebeka Rudolf
Keyword(s):  
Spray Pyrolysis ◽  
Nanoparticle Synthesis ◽  
Ultrasonic Spray Pyrolysis ◽  
Au Nanoparticle ◽  
Evaporation Zone ◽  
Ultrasonic Spray

scholarly journals Optimisation of a Side Inlet for H2 Entry into an Ultrasonic Spray Pyrolysis Device

Processes ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 2256
Author(s):  
Žiga Jelen ◽  
Domen Kandare ◽  
Luka Lešnik ◽  
Rebeka Rudolf
Keyword(s):  
Numerical Simulation ◽  
Numerical Simulations ◽  
Spray Pyrolysis ◽  
Ultrasonic Spray Pyrolysis ◽  
Au Nanoparticle ◽  
Evaporation Zone ◽  
Ultrasonic Spray ◽  
Reaction Tube ◽  
Ansys Cfx ◽  
Inlet Geometry

An ultrasonic spray pyrolysis (USP) device consists of an evaporation and two reaction zones of equal length, into which an aerosol with a precursor compound enters, and where nanoparticles are formed in the final stage. As part of this research, we simulated the geometry of a side inlet, where the reaction gas (H2) enters into the reaction tube of the device by using numerical methods. Mixing with the carrier gas (N2) occurs at the entry of the H2. In the initial part, we performed a theoretical calculation with a numerical simulation using ANSYS CFX, while the geometries of the basic and studied models were prepared with Solidworks. The inlet geometry of the H2 included a study of the position and radius of the inlet with respect to the reaction tube of the USP device, as well as a study of the angle and diameter of the inlet. In the simulation, we chose the typical flows of both gases (N2, H2) in the range of 5 L/min to 15 L/min. The results show that the best geometry is with the H2 side inlet at the bottom, which the existing USP device does not allow for. Subsequently, temperature was included in the numerical simulation of the basic geometry with selected gas flows; 150 °C was considered in the evaporation zone and 400 °C was considered in the other two zones—as is the case for Au nanoparticle synthesis. In the final part, we performed an experiment on a USP device by selecting for the input parameters those that, theoretically, were the most appropriate—a constant flow of H2 5 L/min and three different N2 flows (5 L/min, 10 L/min, and 15 L/min). The results of this study show that numerical simulations are a suitable tool for studying the H2 flow in a UPS device, as the obtained results are comparable to the results of experimental tests that showed that an increased flow of N2 can prevent the backflow of H2 effectively, and that a redesign of the inlet geometry is needed to ensure proper mixing. Thus, numerical simulations using the ANSYS CFX package can be used to evaluate the optimal geometry for an H2 side inlet properly, so as to reconstruct the current and improve future USP devices.

Fireworks: How to Simulate the Manufacture and Operation in the Atmosphere with the Substitution of Ultrasonic Spray Pyrolysis

2018 ◽  
Vol 15 (2) ◽  
pp. 147-156
Author(s):  
Rebeka Rudolf ◽  
Urban Ferčec ◽  
Mohammed Shariq
Keyword(s):  
Spray Pyrolysis ◽  
Final Section ◽  
Web Of Science ◽  
Raw Materials ◽  
Ultrasonic Spray Pyrolysis ◽  
Physiochemical Properties ◽  
Physical Size ◽  
Respiratory Problems ◽  
Ultrasonic Spray ◽  
Temperature Ranges

Background: This review provides a closer look at recent work in the field of fireworks manufacture, which could see the replacement of micron-sized particles with their nano-scaled counterparts. Moreover, we also discuss micron-sized particles as well as nanoparticles (NPs) from K, Fe, Al, Ti, Ba, etc., that are produced in the atmosphere as a result of these fireworks. One of the possible technological substitutes for fireworks is presented in detail, i.e., the use of ultrasonic spray pyrolysis (USP) technology. Method: We searched Google, Web of Science and PubMed for a literature survey of fireworks and their products: firecrackers, micron-sized and nanoparticles. Moreover, we used some of our own knowledge and experimental data to strengthen the possibility of simulating the synthesis of firework products on the laboratory scale. Results: The use of nano reactants and oxidisers has seen a substantial increase in the sound efficiency and a decrease in the amount of chemicals used, making fireworks more eco-friendly. The application of Al- and Ti-based nano flash powder in the size range from 35 nm to 50 μm resulted in a significant improvement in the ignition properties of the fireworks. Under changing aerodynamic conditions, it is difficult to collect them as samples for real-time monitoring, needed for their characterization or the testing of their harmfulness under laboratory conditions. As a result, NPs below 100 nm in the surroundings could be easily inhaled into the lungs and cause more pulmonary and respiratory problems than micron-sized particles. USP produces nanoparticles in the laboratory that could replace the conventional micron-sized firecracker raw materials, or nanoparticles that are similar to those formed by fireworks. It will also help to identify the physiochemical properties of the airborne particulates in order to understand and evaluate their impact. </P><P> This review could be valuable for a controlled economic synthesis through USP, and in the use of nanopowders in pyrotechnology that could reduce pollution to a great extent, thus contributing to the growth and good practise of the fireworks industry. With respect to the USP synthesis, we have also discussed in detail the physical (size, shape) and chemical (composition) characteristics of Al2O3 and TiO2 NPs from different precursors and their temperature ranges. An in-depth explanation for a comparative analysis for the formation mechanism of nanoparticles through both fireworks and USP is presented in the final section. We can produce nanoparticles in the laboratory with ultrasonic spray pyrolysis that have similar properties to those produced from fireworks and can then be used for further testing.

scholarly journals Strong texture tuning along different crystalline directions in glass-supported CeO2 thin films by ultrasonic spray pyrolysis

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Inti Zumeta-Dubé ◽  
José Manuel García Rangel ◽  
Jorge Roque ◽  
Issis Claudette Romero-Ibarra ◽  
Mario Fidel García Sánchez
Keyword(s):  
Thin Films ◽  
Spray Pyrolysis ◽  
Spray Pyrolysis Technique ◽  
Morphological Characteristics ◽  
Ultrasonic Spray Pyrolysis ◽  
Cost Effective ◽  
Growth Direction ◽  
Large Area ◽  
Smart Windows ◽  
Ultrasonic Spray

AbstractThe strong facet-dependent performance of glass-supported CeO2 thin films in different applications (catalysis, smart windows, etc.) has been the target of diverse fundamental and technological approaches. However, the design of accurate, cost-effective and scalable methods with the potential for large-area coverage that produce highly textured glass-supported CeO2 thin films remains a technological challenge. In the present work, it is demonstrated that under proper tuning conditions, the ultrasonic spray pyrolysis technique enables one to obtain glass-supported polycrystalline CeO2 films with noticeable texture along both the (100) and (111) directions, as well as with randomly oriented crystallites (no texture). The influence of flow rates, solution molarity, and substrate temperature on the texture and morphological characteristics, as well as optical absorption and Raman response of the deposited films, is evaluated. The obtained results are discussed on the basis of the combined dependence of the CeO2-exposed surfaces on the thermodynamic stability of the corresponding facets and the reaction kinetics, which modulate the crystallite growth direction.

Transparent MIS capacitors on plastic substrates fabricated by high-frequency ultrasonic spray pyrolysis

2021 ◽  
Vol 44 (2) ◽  
Author(s):  
Ovier Obregon ◽  
José A Luna-Lopez ◽  
Pedro Rosales ◽  
Mario Moreno ◽  
Abdu Orduña-Diaz ◽  
...  
Keyword(s):  
Spray Pyrolysis ◽  
High Frequency ◽  
Ultrasonic Spray Pyrolysis ◽  
Plastic Substrates ◽  
Ultrasonic Spray ◽  
Mis Capacitors
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