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International audience; Spray drying produces spherical agglomerates to obtain powders with good flowability. Three alumina powders of different size and/or specific surface area were spray-dried without any binder using either two-fluid or ultrasonic nozzle technology. Compared to the two-fluid nozzle, the ultrasonic one shows a better ability to form agglomerates from a coarse powder and increases the size of the agglomerates when spray drying is carried out under the same operating conditions. The redispersion of spray-dried agglomerates in solution was analysed by applying variable ultrasound durations during size measurement by wet laser diffraction. The initial state of the powder plays a predominant role in relation to the spray drying operating conditions both in terms of size characteristics and redispersion properties. Regardless of the alumina powders and spray drying conditions, a similar trend in deagglomeration behaviour was observed with first-order kinetics and a characteristic kinetic time depending on the initial powder properties.

In minimum quantity lubrication (MQL) machining, a small quantity of cutting fluid is air-atomized to generate fine liquid droplets, and they are injected into the machining zone. The effectiveness of the MQL system depends on the droplet size/distribution, spray shape, spray velocity, and area fraction covered by the droplets. In the present study, for the first time, a novel MQL nozzle has been designed and manufactured applying ultrasonic vibrations using piezoelectric discs tighten on the nozzle between the mechanical amplifying element and a support element. Ultrasonic vibrations can be used to effectively atomize the cutting fluid into fine and uniform-sized droplets and smaller spray angle with a larger spray deposition distance. Ultrasonic nozzle–minimum quantity lubrication (UN-MQL) system generates a mist-like uniform spray. The ultrasonic nozzle was designed and analyzed using the SolidWorks and Ansys Workbench software. Image processing techniques have been used to characterize the droplet sizes, and the droplet distribution after the oil has been sprayed onto a polished lead-coated plate by UN-MQL system as well as better understanding in the application of the ultrasonic nozzle for its effective use in practical industrial applications. A set of experiments have been conducted on AISI 304L stainless steel during turning with the developed setup, and the results have been compared with dry, wet, and conventional MQL turning processes. The fine droplets produced by the UN-MQL system penetrate effectively into the machining zone and consequently enhance the cooling-lubrication characteristic in the cutting zone. Spray angle of UN-MQL in comparison to conventional MQL systems decreased about 40% and 30% in air pressure of 6 and 3 bar, respectively. The rising inclination of the area fraction covered by droplets in variable air pressures has improved approximately 70% among the oil flow rates of 16 to 110 ml/h in the UN-MQL case as opposed to the conventional MQL system. The greatest quantity of decrement in mean droplet diameter which transpired in air pressure of 1 bar, reached nearly 63% for the oil flow rates of 16 ml/h, 30 ml/h, and 43 ml/h. Overall, the results obtained during UN-MQL turning experiments show that the surface roughness has been improved compared to dry, flood, and conventional MQL turning processes.

Titanium dioxide (TiO2, rutile) nanoparticles, inorganic ultraviolet absorbers, are used extensively in sunscreen cosmetics as an inorganic ultraviolet (UV) absorber to prevent skin damage; because of their nanotoxicity, use in combination with a support, such as montmorillonite (Mnt), rather than alone, is suggested. Mnt-supported TiO2 composites (Mnt-TiO2) for sunscreens are most suitable when the particles are spherical and of relatively uniform size, which are normally accomplished by spray drying, but this is difficult to achieve because of the naturally layered structure of Mnt. The objective of the present study was, therefore, to find the ideal characteristics of spray-drying nozzles to produce the desired spherical shape and size distribution of the Mnt-TiO2 composite particles. The starting Mnt was extracted from natural bentonite by particle-size separation. An ultrasonic nozzle in the spray dryer was selected for use in the synthesis of Mnt-TiO2 composites based on the particle-size distribution (PSD) of Mnt prepared using a two-fluid nozzle and an ultrasonic nozzle at 453 K. The incorporation of TiO2 in the final Mnt-TiO2 composites was examined by X-ray powder diffraction (XRD) and elemental analysis. With increasing TiO2 concentration, the TiO2 content and average particle size of the Mnt-TiO2 composites increased. Scanning electron microscopy (SEM) images showed that all samples prepared had uniform and nearly spherical shapes. Absorbance of UV by Mnt-TiO2 (5:1) composites was greater than that by either purified Mnts or pure TiO2. The present study demonstrated a simple method, using a spray dryer with an ultrasonic nozzle, to synthesize Mnt-TiO2 composites of uniform size and shape suitable for cosmetic application.

BACKGROUND An ultrasonic spray nozzle was evaluated for the production of powders and microcapsules, using blueberry extract, modified starch (HI-CAP 100), and whey protein isolate (WPI). The effects of ultrasonic power and the concentration of coating materials on the characteristics of the resulting samples - such as viscosity, particle size, microencapsulation efficiency, color, glass transition temperature, Fourier-transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), and morphology - were also studied. RESULTS The apparent viscosity was primarily affected by the self-heating of the ultrasonic nozzle as the power increased. The largest mean particle size of samples was observed under conditions of 30% coating concentration at 10 W. Glass transition temperatures (Tg ) of the samples were affected by all atomization parameters significantly (P

The purpose is to present the application of the acoustic levitation as a model system for a coating process with non-spherical and light particles in the fluidized bed reactor. An acoustic levitator has been used to track a pellet in a contactless position by Raman spectroscopy, while it was coated with polyvinylpyrrolidone by an ultrasonic nozzle. The Raman data were evaluated by a principal component analysis and a multivariate curve resolution. The pellets had a maximum size of 1.0 mm. To develop an optimization model, a design of experiments was performed in the acoustic levitator. The obtained optimization model demonstrated that the mass fraction of polyvinylpyrrolidone in the coating solution, the temperature and the optional air stream affected the coating thickness. To validate the optimization model, the pellets were coated in the acoustic levitator and in a fluidized bed reactor under the same conditions. The coated pellets had similar morphologies.

Zeolites are microporous crystalline materials widely used in catalysis and adsorption applications. The fabrication of zeolite thin films and membranes has also opened up the possibility of using zeolites in electronic devices and membrane separations. The existing approach to growing zeolite films involves exposing the substrate to a high-pH environment; however, this process is applicable to only specific types of substrates. Our group has developed the direct wet deposition of zeolites via ultrasonic nozzle spray deposition to address this issue; however, the relationship between wetting properties and thin-film quality has yet to be investigated. In this study, we prepared zeolite CHA (Si:Al:P = 3:10:20) suspensions using different solvents and surfactants in various concentrations. We then examined the relationships among the composition of the cast solution, their wetting behavior on the glass substrate, and the uniformity of the resulting thin films. We found that using ethanol as a solvent with zeolite crystals in low concentrations with added surfactant yielded zeolite films of high quality. We were also able to produce low-haze zeolite coatings on glass. The zeolite coatings with high hydrophilicity and adsorption capacity presented excellent antifogging capability.

Improvements in the membrane separation of whey and subsequent spray drying for the recovery of Whey Protein Concentrate (WPC) have been investigated in the present work. Initially, ultrasonic pretreatment of whey was performed to reduce the microbial contamination and possibly improve the membrane separation based on inducing changes in the whey proteins. Studies involving the effect of important parameters in the membrane operation such as transmembrane pressure (TMP), type of membrane and molecular weight cutoff (MWCO) on permeate flux established that 10 kDa hydrosart membrane gives maximum permeate flux with minimum fouling at an optimum TMP of 1.2 bar. Studies with ultrasound assisted ultrafiltration established that the fouling was reduced with ultrasound also giving higher permeate flux. Effect of spray drying parameters such as air pressure, aspirator rate (rpm), feed flow rate and dilution on the WPC yield, analysed using SDS-PAGE and Kjeldahl method, has also been investigated. Additionally, the use of ultrasonic nozzle in the spray drying was investigated and the results were compared with pneumatic nozzle. Overall, it was clearly established that pretreatment, membrane characteristics, ultrafiltration operating parameters and spray drying parameters play an important role in deciding the WPC recovery from whey. Significant process intensification benefits were demonstrated to be obtained with the use of ultrasound both in membrane separation and spray drying.

This work is devoted to the use of modern computer simulation tools based on the principles and methods of computational fluid dynamics that are applied to develop processes and equipment for producing spray dried micropowders. The feed solution was atomized into small droplets using an ultrasonic nozzle that exploits the principle of liquid disintegration caused by impact of high-frequency wave oscillations. The use of this device for spraying a liquid allowed obtaining spherical particles with diameters less than 20 μm and with a narrow size distribution. The process development is based on a mathematical model incorporating the hydrodynamics, heat and mass transfer mechanisms, which has been formulated to numerically predict particles trajectories and temporal changes of their mass and temperatures. The generated data were used to analyze the trajectories of discrete phase particles considering various process parameters and to estimate adhesion of wet particles to the drying chamber and nozzle...

Medicinal particles or aerosols of the size range from 1 to 5 µm at high output rates are required for efficient and effective inhaled drug delivery to rapidly administer a large dose of medicine to the lung. Current commercial devices all suffer from broad aerosol size distributions, with a geometrical standard deviation (GSD) range of 1.5 to >4.0, making it difficult to deliver sufficient drug to targeted sites precisely and rapidly. The silicon-based megahertz multiple-Fourier horn ultrasonic nozzles (MFHUNs) presented in this dissertation have been shown capable of producing such micrometer-sized particles (aerosols) at high output rate and low electrical drive power. The precise control of aerosol size and much narrower size distribution achieved by the new device will greatly improve targeting of treatment within the respiratory tract and improve delivery efficiency, resulting in better efficacy, fewer side effects, shorter treatment times, and lower medication costs compared with the existing nebulizers. The basic ultrasonic nozzle consists of a drive section and a resonator section with a lead zirconate titanate (PZT) transducer bonded on the drive section to excite large mechanical vibrations on the end face of the distal horn to initiate instability of megahertz (MHz) Faraday waves on the free liquid surface. In operation, a medicinal liquid layer with a certain thickness is formed on the end face of the nozzle tip via a silica tube. The dramatic resonance effect among the multiple Fourier horns and high growth rate of the MHz Faraday waves excited on the medicinal liquid layer together facilitate ejection of monodisperse aerosols of desirable size range (2-5 µm) at low electrical power(

In order to produce clean and low cost electricity from solar energy, it is important to establish a cost effective solution processable and scalable technique compatible with high throughput Roll-to-Roll processes. This report focuses on the optimization of ultrasonic spray deposition of the active layer for the fabrication of scalable efficient organic bulk heterojunction devices. The ultrasonic nozzle enables us to atomize the solution with picoliter drop size which gives uniform coverage and smooth film over a large area. The various parameters of the process formation were systematically investigated and optimized to get a pin-hole free, smooth and uniform film with low resistivity. Rational device optimization were carried out by one to one performance comparison between the devices fabricated by ultrasonic spray techniques and standard spin coating technique. The comparable results establishes the practical feasibility of our approach for large scale industrial applications.

In this study, research was performed on the interesterification reaction of cotton oil with methyl acetate, using potassium methoxide as catalyst, in the presence of ultrasonic waves. In order to obtain a better understanding of the process variables behavior, a response surface methodology was used along with statistical methods. The experiments were performed with molar ratio varying from 1:8 to 1:24, catalyst percentage of 0.1 to 1.3% (weight), ultrasonic nozzle amplitude varying from 30% to 90% (180 to 540 W) and vibration pulse varying from 50% to 90%. Process variables were optimized with the optimal molar ratio of 1:14.87, catalyst concentration of 1.17%, ultrasonic probe amplitude of 67.64% and vibration pulse of 67.30%. The average conversion of triglycerides was found to be 98.12% at the optimal conditions. The experimental data were adjusted to the second-order irreversible reaction approximation model, under optimized conditions, with temperatures of 30, 40 and 50 ºC. Lastly, in comparison to the conventional methodology, a significant increase of 14% of triglycerides conversion utilizing ultrasonic waves was observed.

Zeolite thin films with ordered nanopores and a low dielectric constant can serve as an insulation layer in microelectronic devices. However, the absence of a high-throughput deposition technique is a major technical hurdle in the industrial-scale production of zeolite thin films. Herein, we report on a scalable method, ultrasonic nozzle spray deposition (UNSD), which addresses this issue. A high-frequency standing wave introduced by the ultrasonic nozzle produces uniform sized droplets of the cast suspensions at a scale of tens to hundreds of micrometers, which results in a uniform thin film following the removal of the solvent. In this paper, we focus on the deposition of thin films comprising pure-silica zeolite MFI on a silicon wafer substrate. We systematically investigated how the quality of the zeolite thin films is affected by the composition of the cast suspensions and UNSD operating parameters. We identified the UNSD operating window that allows for the fabrication of uniform dense zeolite thin films at thicknesses ranging from hundreds of nanometers to 3 μm. We determined that zeolite MFI thin films prepared using UNSD outperformed those fabricated using conventional spin-on deposition in terms of uniform film thickness, low leakage current, and high Young's modulus.

In this work, novel amorphous solid dispersions based on yeast glucan particles were produced. Yeast glucan particles are hollow and porous, and they are mainly composed of amorphous polysaccharides. We hypothesized that these particles are suitable candidates for the amorphization of drugs with low water solubility. Model drugs ibuprofen and curcumin were successfully encapsulated in glucan particles by spray drying. Different spray-drying parameters were tested to evaluate the influence of atomizing droplet size and initial solid content on encapsulation efficiency. It was shown that higher solid content and, more significantly, larger droplet sizes lead to higher encapsulation efficiencies. The encapsulation efficiency of ibuprofen (10 wt%) into glucan particles was considerably improved from 41.3 ± 0.5% to 64.3 ± 0.2% by increasing initial solid content and droplet size with the two-fluid nozzle. The spray drying process was further optimized by using the ultrasonic nozzle and it was possible to achieve complete encapsulation of ibuprofen and curcumin without any precipitation of the active compound outside of the glucan particles. Overall, it was possible to produce completely amorphous composites with outstanding wettability and dispersion properties, and with significantly faster dissolution rates when compared to the micronized crude drug.

The effects of the fuel temperature on diesel nozzle internal flow and the subsequent atomization were analyzed experimentally. Flow visualization was studied using a 10-times scaled-up transparent acrylic model nozzle with different geometries. A high-speed digital camera was used to capture the flow pattern in the region of the sac chamber and the nozzle. The energy loss in the occurrence of the hydraulic flip was also analyzed. In addition, cavitation images obtained in the multi-hole tapered nozzle with different fuel temperatures had revealed that although the conical shape of the converging tapered holes suppresses formation of geometry-induced cavitation, string cavitation has been clearly observed anyway. Afterward, the experimental method was used to analyze the effects of the nozzle sac volume structure on the cavitation flow inside the nozzle and subsequent spray. It was found that the in-nozzle flow stage and spray formation were sensitive to the fuel temperature. The visual experiment is helpful to understand the nozzle flow and optimize the diesel injectors eventually.

Liquid injection into a fluidized bed is employed in several chemical processes in order to maximize contact between liquid reactants and solid particles. For example, in the Fluid Coking™ process, droplets contact the bed particles and form wet agglomerates that impair heat transfer from the hot bed to the reacting liquid, slowing down its endothermic cracking reactions. Agglomerate formation, thus, results in reduced reactor operability and a lower yield of valuable liquid product. The objective of this paper is to test the effect of different nozzle attachments on the rate at which moisture is released from agglomerates in a large scale fluidized bed. The addition of a conical nozzle attachment impacts the performance of the spray inside a fluidized bed. An optimal diverging nozzle tip angle of 20° has been identified. This nozzle tip produces an open air spray angle similar to that produced by a regular nozzle, without an attachment. Increasing the diverging nozzle tip angle beyond 20° reduces the penetration length of the spray, and may induce detrimental instabilities downstream of the spray. Reducing the diverging nozzle tip angle stabilizes the spray, and increases its penetration depth; however, it also significantly reduces the jet-bed interfacial area, thereby reducing the number of solid particles wetted by the spray. As a result, stronger agglomerates are produced, that take longer to release trapped liquid into free moisture. The cloverleaf nozzle attachments improve the performance of the standard spray nozzle by increasing the interfacial area between the jet and the bed.

The ultrasonic nozzle (US) spray method was investigated for its utility in fabricating organic electrodes composed of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS), a standard conductive polymer material used to produce large-area low-cost OFETs. The US spray technique involves generating a solution spray by first passing the solution through a head and nozzle subjected to ultrasonic vibrations that induce atomization. This method is advantageous in that the resulting spray comprises extremely small solution droplets a few micrometers in diameter, unlike the spray produced using conventional air spray methods. The PEDOT:PSS US solution spraying process was optimized by controlling the flow rate of the N 2 carrier gas and the substrate temperature while monitoring the quality of the resulting PEDOT:PSS electrode films. The pentacene field-effect transistors prepared using the US spray method displayed a maximum field-effect mobility of 0.47 cm 2 V −1 s −1 (with an average value of 0.31 cm 2 V −1 s −1 ), 35% better than the mobilities achieved using the conventional air spray method. In addition, the device-to-device reproducibility was improved, as indicated by a decrease in the standard deviation of the mobility values from 30% for the air spray devices to 24% for the US spray devices. These results indicated that the US spray technique is efficient and superior to the conventional air spray method for the development of low-cost large-area organic electronics.

Fuel spray plays more vital role in governing fuel economy and emission quality of IC engines due to the wide application of direct injection system in automotive engines. High temperature fuel spray, namely flash boiling spray, has been documented to improve fuel atomization and evaporation with less energy consumption compared with high pressure fuel spray. It is because the hot exhaust gas and coolant are two potential energy sources can be used to heat the fuel. Most of existing research works of flash boiling spray focus on investigating the spray behavior outside the nozzle, and limited studies can be found about the in-nozzle superheated flow. In this study, a two-dimensional transparent slit nozzle was designed to reveal the in-nozzle flow under various superheated conditions. Both internal flow and near-nozzle fuel jet were investigated using high-speed backlit imaging technique to acquire a better understanding of the primary breakup process of flash boiling sprays. The slit thickness was 40 μm with well-adjusted nozzle length and inlet corner radius to investigate the effects of nozzle configuration. The ambient pressure ranged from 40 kPa to 190 kPa, and fuel temperature varied from 41 °C to 71 °C, which produced a wide range of superheated conditions. N-pentane was chosen as test fluid with an injection pressure of 0.6 MPa. Experimental results showed that the bubbles occurring inside the nozzle near the nozzle exit affected the near-nozzle fuel jet characteristics. Stronger superheated conditions resulted in larger in-nozzle bubbles, which facilitated the jet break-up process significantly. Longer nozzle and nozzle with sharp inlet corner led to larger inner bubble volume fraction and narrower liquid core of near-nozzle fuel jet. In summary, the effects of nozzle configuration on in-nozzle flow and near-nozzle fuel jet were revealed with more fundamental understanding of the primary breakup process of flash boiling sprays.

It is widely recognized that a well atomized spray promotes the fuel evaporation in engine cylinder and contributes to higher fuel efficiency and lower exhaust emission. Specifically, higher fuel temperature enhances the fuel spray evaporation due to the superheat phenomenon even at low injection pressure. In this study, both internal flow and near nozzle fuel jet of a two-dimensional transparent nozzle were investigated using high-speed backlit imaging technique to acquire a better understanding of the primary breakup process of flash boiling sprays. The two-dimensional slit transparent nozzle was designed to facilitate the enhanced visualization of bubbles inside the nozzle by squeezing small bubbles and eliminating overlapping bubbles. The ambient pressure ranged from 40 kPa to 190 kPa, and fuel temperature varied from 41 °C to 71 °C, to produce a wide range of superheated conditions. N-pentane was chosen as test fluid with an injection pressure was 0.5 MPa. Experimental results show that the bubbles occurring inside the nozzle near the nozzle exit under flash boiling conditions affect the shape and dynamic behavior of near nozzle fuel jet. It shows that higher fuel temperature and lower ambient pressure increase the inner bubble size and volume fraction, which led to narrower liquid core of near nozzle fuel jet. Inner bubbles facilitate the breakup process of fuel jet significantly. The breakup process of flash boiling spray can be elucidated with more fundamental understanding of bubble behavior inside the nozzle.

Partially purified microbial transglutaminase (mTG) was microencapsulated by ultrasonic spray-freeze drying (USFD) as a novel method, using a 48 kHz ultrasonic nozzle. The microencapsulated samples, which used a mixture of inulin and gum arabic as coating materials, were compared to microencapsulated samples by conventional freeze-drying (CFD) and conventional spray drying (CSD) in terms of thermal stability. Thermal inactivation kinetics of the microencapsulated and as well as crude enzymes obtained by USFD process (USFD-crude) were evaluated according to first-order reaction kinetics in the range of 40-60 degrees C at different pH values (5.0-7.0), and the activation energy (E-a, kJ/mol) and free energy for thermal inactivation (Delta G, kJ/mol) were calculated. Furthermore, the specific surface area (SSA, m(2)/g) of the samples was determined, and a relationship between SSA and thermal stability was established. The results showed that the thermal stability of micro encapsulated mTG by USFD was higher than all samples, having smaller rate constants and E-a values with higher half-life times and Delta G values. In addition, the thermal stability of the samples decreased when the SSA increased, as in USFD-crude and CSD samples.

The atomized nutrient solution droplet sizes and spraying intervals can impact the chemical properties of the nutrient solution, biomass yield, root-to-shoot ratio and nutrient uptake of aeroponically cultivated plants. In this study, four different nozzles having droplet sizes N1 = 11.24, N2 = 26.35, N3 = 17.38 and N4 = 4.89 &micro, m were selected and misted at three nutrient solution spraying intervals of 30, 45 and 60 min, with a 5 min spraying time. The measured parameters were power of hydrogen (pH) and electrical conductivity (EC) values of the nutrient solution, shoot and root growth, ratio of roots to shoots (fresh and dry), biomass yield and nutrient uptake. The results indicated that the N1 presented significantly lower changes in chemical properties than those of N2, N3 and N4, resulting in stable lateral root growth and increased biomass yield. Also, the root-to-shoot ratio significantly increased with increasing spraying interval using N1 and N4 nozzles. The N1 nozzle also revealed a significant effect on the phosphorous, potassium and magnesium uptake by the plants misted at proposed nutrient solution spraying intervals. However, the ultrasonic nozzle showed a nonsignificant effect on all measured parameters with respect to spraying intervals. In the last, this research experiment validates the applicability of air-assisted nozzle (N1) misting at a 30-min spraying interval and 5 min of spraying time for the cultivation of butter-head lettuce in aeroponic systems.

We investigated a spray-drying aerosol generator that can generate micro-particles at high concentration using an ultrasonic nozzle. Unlike a conventional spray-drying aerosol generator that uses vertical spray with co-current sheath flow, we designed a new aerosol generator by using horizontal spray with co-current sheath flow combined with clean counter flow to increase particle generation efficiency. A drying chamber was designed using the ANSYS Fluent solver to complete the evaporation of droplets and to minimize the loss of post-evaporation particles inside the chamber. Both numerical prediction and experimental data showed that droplets would completely evaporate at a temperature of 353 K. Both KCl aqueous solution and silica powder suspension were sprayed using an ultrasonic nozzle to generate micro-sized particles with a size range of 1–10 μm. When horizontal spray with co-current sheath flow was operated with clean counter flow the loss of particles on the chamber wall was minimized and thus the total particle number concentration was 2.4 times higher than when the clean counter flow was inactive. The particle generator in the present study can generate larger particles than a Collison atomizer which generates particles up to 3 μm.

The effects of nozzle geometry on diesel spray characteristics were studied in a spray chamber under evaporating conditions using three single-hole nozzles, one cylindrical and two convergent, designated N1 (outlet diameter 140 μm, k-factor 0), N2 (outlet diameter 140 μm, k-factor 2) and N3 (outlet diameter 136 μm, k-factor 2). Spray experiments were performed with each nozzle at two constant gas densities (15 and 30 kg/m3) and an ambient temperature (673 K) at which evaporation occurs, with injection pressures ranging from 800 to 1600 bar. A light absorption and scattering method using visible and UV light was implemented, and shadow images of liquid and vapor phase fuel were recorded with high-speed video cameras. The cylindrical nozzle N1 yielded larger local vapor cone angles than the convergent nozzles N2 and N3 at both gas densities, and the difference became larger as the injection pressure increased. The vapor phase penetration values for nozzle N1 and N3 were quite similar and always lower than those for N2. This is consistent with the impingement measurements, which showed that the momentum flux of nozzle N1 was only slightly greater than that of nozzle N3, while that of nozzle N2 was substantially greater. The vapor volume fractions measured along the spray’s center line were well explained by the one-dimensional transient diesel jet model, indicating that diesel spray vaporization is controlled by turbulent fuel-air mixing.

There is a need to develop instrumented witness plates which would be possible to expose in natural environments after laboratory validation. In conventional laboratory scale test chambers, the main difficulty remains the access of any kind of sensor to the tested metallic target for continuous monitoring. It is proposed to generate a well-controlled spray by an ultrasonic nozzle focused on the surface of very thin AA2024 foils positioned in a compact test cell which renders possible the access to the backside of the target. Validation in terms of corrosion damage of remote sequential experimental procedure using an ultrasonic nozzle programmed to pulse is illustrated.

In cold gas dynamic spraying, the gas nature, process stagnation pressure and temperature, and the standoff distance are known to be important parameters that affect the deposition efficiency and coating quality. This investigation attempts to elucidate the effect of nozzle material on coatings produced using a downstream lateral injection cold spray system. Through experimentation, it is shown that the nozzle material has a substantial effect on deposition efficiency and particle velocity. It is proposed that the effects are related to complex interaction between the particles and the internal nozzle walls. The results obtained lead to the conclusion that during the particle/nozzle wall contact, a nozzle with higher thermal diffusivity transfers more heat to the particles. This heat transfer results in lower critical velocities and therefore higher deposition efficiencies, despite a noticeable reduction of particle velocities which is also attributed to particle-nozzle interactions.

Purpose The potential of aerosol phage therapy for treating lung infections has been demonstrated in animal models and clinical studies. This work compared the performance of two dry powder formation techniques, spray freeze drying (SFD) and spray drying (SD), in producing inhalable phage powders. Method A Pseudomonas podoviridae phage, PEV2, was incorporated into multi-component formulation systems consisting of trehalose, mannitol and L-leucine (F1 = 60:20:20 and F2 = 40:40:20). The phage titer loss after the SFD and SD processes and in vitro aerosol performance of the produced powders were assessed. Results A significant titer loss (~ 2 log) was noted for droplet generation using an ultrasonic nozzle employed in the SFD method, but the conventional two-fluid nozzle used in the SD method was less destructive for the phage (~0.75 log loss). The phage were more vulnerable during the evaporative drying process (~0.75 log further loss) compared with the freeze drying step, which caused negligible phage loss. In vitro aerosol performance showed that the SFD powders (~80% phage recovery) provided better phage protection than the SD powders (~20% phage recovery) during the aerosolization process. Despite this, higher total lung doses were obtained for the SD formulations (SD-F1 = 13.1 ± 1.7 ×104 pfu and SD-F2 = 11.0 ± 1.4 ×104 pfu) than from their counterpart SFD formulations (SFD-F1 = 8.3 ± 1.8 ×104 pfu and SFD-F2 = 2.1 ± 0.3 ×104 pfu). Conclusion Overall, the SD method caused less phage reduction during the powder formation process and the resulted powders achieved better aerosol performance for PEV2. This work was financially supported by the Australian Research Council (Discovery Project DP150103953). Authors are grateful to Tony Smithyman of Special Phage Services for his valuable discussion and advice. Sharon Leung is a research fellow supported by the University of Sydney. Thaigarajan Parumasivam is a recipient of the Malaysian Government Scholarship.

BACKGROUND Recently, ultrasonic nozzle technology has been applied in spray-drying because of its numerous advantages, including providing more uniform droplets and reducing damage observed in bioactive compounds. In this study, the production of blueberry powders and microcapsules by using an ultrasonic spray nozzle was investigated. Firstly, the important ultrasonic nozzle parameters were optimised by using response surface methodology and compared with a conventional nozzle (control). Secondly, powder and microcapsules obtained at the optimum point were stored at 22 °C and 35 °C at 0.32 water activity (aw ). RESULTS The optimum conditions were estimated as 125 °C inlet air temperature, 9 W ultrasonic power and 8% feed pump rate. There was significantly difference (P < 0.05) in the total phenolic content and antioxidant power of microcapsules produced by an ultrasonic nozzle and a conventional nozzle. Because the temperature affected the stability of powders negatively, the blueberry powder showed higher losses than microcapsules in the content of bioactive compounds. In addition, the ultrasonic nozzle showed a significantly greater protective effect on physico-chemical properties than did the conventional nozzle. CONCLUSION Results of the study point that the production of ultrasonic nozzle powders and microcapsules is feasible to use as a functional ingredient in food industry. © 2016 Society of Chemical Industry.

Tese de mestrado, Engenharia Farmacêutica, Universidade de Lisboa, Faculdade de Farmácia, 2018 Submitted by Repositório FFUL (repositorio@ff.ul.pt) on 2019-11-04T19:21:02Z No. of bitstreams: 1 TM_Mariana_Silva.pdf: 7216212 bytes, checksum: 9d9400cddff9a9374e54d84693617558 (MD5) Made available in DSpace on 2019-11-04T19:48:40Z (GMT). No. of bitstreams: 1 TM_Mariana_Silva.pdf: 7216212 bytes, checksum: 9d9400cddff9a9374e54d84693617558 (MD5) Previous issue date: 2018-11-29 Hovione FarmaCiência

The experiment apparatus of ultrasonic vibration-assisted microabrasive waterjet polishing is developed. The simulation model of ultrasonic nozzle is analyzed with the help of ANSYS software. The simulation result shows that the ultrasonic vibration leads to a good result that the maximum frequency with the value of 20908 Hz is obtained at the outlet of ultrasonic nozzle, and the vibration type is axial mode. Then the vibration frequency and amplitude of the developed experiment apparatus are tested using the ultrasonic transducer impedance analyzer and the laser displacement sensor. The measured result indicates that the vibration frequency is 19099 Hz and the amplitude is 22 μm, which means the experiment apparatus is well developed and satisfies the work requirements. The verifying experimental result shows that the ultrasonic vibration helps to enhance the machining ability of the abrasive waterjet, and the removal material volume and erosion depth are increased obviously.