Droplet Size Measurements Research Articles

Efficacy of D-Limonene Nanoemulsion Against Rhipicephalus annulatus and Rhipicephalus sanguineus Ticks.

Ticks infestation has a negative impact against human and animal health through blood sucking, transmission of blood-borne diseases and also caused economic losses. In the present study the adulticidal, ovicidal and larvicidal activity of D-limonene nanoemulsion (DLN) were evaluated against two tick species; Rhipicephalus annulatus and Rhipicephalus sanguineus. Nanoemulsion form of D-limonene was prepared, and its characteristics were evaluated using a UV spectrophotometer and zeta droplet size measurement. Acetylcholinesterase activity was determined. The results revealed significant adulticidal effect with low LC50 and LC90 for D-limonene pure form (DL) against both adult tick spp. (R. annulatus and R. sanguineus) ((0.958 and 1.559%) and (2.26 and 3.51%), respectively). DLN LC50 and LC90 values were ((1.277 and 2.396) and (3.97 and 7.28), respectively) against R. annulatus and R. sanguineus, respectively. DL and DLN showed significant ovicidal effect against R. sanguineus at high concentrations (10 and 5%). In larval packet test, LC50 and LC90 values of DL were ((1.53 and 2.22%) and (6.81 and 12.07%), respectively) against R. annulatus and R. sanguineus, respectively, while LC50 and LC90 values of DLN were ((6.48 and 11.26%) and (7.82 and 13.59%), respectively) against R. annulatus and R. sanguineus, respectively. Significant acetylcholinesterase inhibition percentage was detected for both ticks spp. which treated by DL and DLN. Pure DL is more effective than DLN form against R. annulatus and R. sanguineus.

Droplet Size and Velocity Measurement in Annular Flow by Fiber Optical Reflectometer

Droplet Size and Velocity Measurement in Annular Flow by Fiber Optical Reflectometer

Measurement of inkjet droplet size based on Fraunhofer diffraction.

Inkjet printers have started to manufacture OLED/QLED pixel arrays for the display industry, and the precise measurement and control of ink droplet volume during the printing process has become important. We investigated the feasibility of Fraunhofer diffraction analysis as a volume measurement tool for fast-moving inkjet droplets. To confirm the basic idea, two Fraunhofer diffraction-based methods were used to calculate the wire diameters of well-known sized and steady-positioned metal wires. The first method was to curve-fit the whole measured diffraction intensity curve with the extensive Fraunhofer diffraction equation. The second one was to use the simple approximate diameter calculation equation with the measured position data of minimum diffraction intensity. The metal wire diameters calculated by the two methods showed less than 1.17% error. For the size measurement of fast-moving inkjet droplets, the first method showed 24.5 µm diameter and 7.7 pL volume, while the second method showed 25.4 µm diameter and 8.58 pL volume. We found that the second method was more suitable for real-time inkjet monitoring because its average computer calculation time was 33ms, and the first method took an average of 34ms, about 1000 times more CPU time. Hence, Fraunhofer diffraction analysis as an inkjet droplet volume measurement tool was feasible with a good balance of measurement time and measurement accuracy.

PREPARATION AND OPTIMIZATION OF CILOSTAZOL NANOEMULSION ORAL LIQUID DOSAGE FORM

Objective: Cilostazol has poor water solubility and low oral bioavailability. Therefore, the formulation of cilostazol as a nanoemulsion may enhance its solubility and improve oral bioavailability. Hence, the aim of this study was to formulate and characterize an oil-in-water (o/w) nanoemulsion of cilostazol as an oral liquid dosage form. Methods: Pseudo-ternary phase diagrams were constructed using the aqueous titration method. Formulations of pseudo-ternary phase plots consisting of oil, various weight ratios of S mix (mixture of surfactant and co-surfactant), and deionized water were made. Different characterization studies, droplet size measurement, polydispersity index, drug content, zeta potential measurement, and in vitro release have been conducted to choose the optimized formula. Results: The characterization studies have demonstrated that the optimized formula is (F-6), consisting of 20 % S mix (3:1), 10% ginger oil, and 70% deionized water. This formula had the following characteristics; droplet size (72.9-110 nm), polydispersity index (0.22), percentage of drug content (99.8%), and in vitro release of cilostazol nanoemulsion was significantly higher (P<0.05) in comparison with other formulations. A Scanning probe microscopy (SPM) study has revealed that the droplet size of F-6 was at the nano-scale. Conclusion: In conclusion, the optimized cilostazol formula (F-6) is a promising formula which may have the capability of improving the oral bioavailability of cilostazol.

Numerical and experimental investigation of the droplet size for MQL aerosol under different operating parameters with Flow visualization

Minimum quantity lubrication (MQL) is a sustainable machining process in which oil and air are mixed to form a spray that can be directed to the cutting zone. MQL spray factors like droplet size and velocity and their effect on machining remain unclear, especially when employing diverse oils and operating settings. Mist formation factors determine how well spray droplets lubricate the targeted area during machining. Numerical and Experimental studies were conducted with different values for MQL parameters like cutting oil type, air pressure and oil flow rate, to establish the best possible combination to give the ideal droplet size and surface roughness. The study utilized three types of oils and varied air pressures to evaluate the cooling effectiveness of MQL spray during end milling operations. Experimental droplet size and velocity measurements were obtained using ‘Phase Doppler Anemometry (PDA)’ and ‘Particle Image Velocimetry (PIV)’ techniques. A numerical model within ANSYS Fluent software, employing computational fluid dynamics (CFD), predicted spray flow properties and was validated using PIV data. Raising the air pressure decreased the droplet size, while increasing velocity to achieve greater overall speed and enhanced lubrication in the cutting region. Changing the coolant flow rate or the compressed air pressure affected the Sauter mean diameter (SMD) of oil particles. The research showed that increasing air pressure from 1 bar to 3 bar reduced surface roughness by 55.40 percent and SMD by 24.58 percent for 120V oil. Among the three cutting oils tested, the 120V oil achieved the lowest surface roughness at 0.227μm under specific conditions: a flow rate of 150 ml hr−1, pressure of 3 bars, and SMD of 35.5 μm. These findings provide valuable insights into improving MQL efficiency for machining operations.

A solenoid injector based drop-on-demand system for generating large droplets.

This paper proposes a drop-on-demand (DOD) system that can produce single droplets of highly repeatable size in the order of 2mm. This system utilizes an on-the-shelf solenoid injector used in automotive applications. The design methodology is explained along with the necessary measurements and numerical simulations of droplet generation. The invention consists of a solenoid injector that produces monodisperse single or in-series droplets with the help of a developed pulse width modulated signal generator. Mass per injection is measured over a range of supply pressures and injection durations to find the operation window to generate 2mm droplets. Later, various nozzle geometries are designed and tested by flow simulations. The contracting nozzle is found suitable for generating single droplets, so the design is implemented at the tip of the solenoid injector. The effects of different opening times, pressures, and nozzle's orifice diameters were tested to observe the operating window of the newly designed DOD system and the repeatability of generated droplets by utilizing a coherent circular Hough transform image processing algorithm to measure droplet sizes. The standard deviation of measured diameters is less than 5% of the mean droplet diameter, which is in the range of 1.68-2.07mm. Next, the voltage and current signals are measured per injection, and exact instants for the initiation and ending for both opening and closing are determined to construct transient mass flow rate functions for flow simulations in which the dependence of droplet formation on the speed of closing is revealed. The numerical and experimental results indicate the repeatability and consistency of the invention.

Development and evaluation of precision liquid pollinator for kiwifruit

Cultivation of kiwifruit heavily relies on assisted pollination, and sufficient pollination can enhance fruit quality. A precision liquid pollinator for kiwifruit robotic pollination was developed as part of the research, and it was optimized with the aim of improving pollination quality while saving pollen usage. The pollinator employs a grating ruler to measure the stroke of a pneumatic hydraulic cylinder to achieve precise control of pollen suspension dosage, and uses an internal mixing air-assisted nozzles to spray pollen suspension for pollination. Through experiments of optimizing pollen suspension volume control, constructing of pollination distance prediction model, and measuring droplet size distribution, a working range of air pressure and liquid pressure was established. Eight sets of air–liquid pressure parameters were selected to evaluate the planar pollen deposition of the pollination device, and the optimal parameters were applied to pollinate kiwifruit flowers. The results indicated that reducing droplet size enhanced the overall pollen deposition rate.. In a windless laboratory environment, the developed pollinator achieved a pollen deposition efficiency of 21.15% under an air pressure of 0.15 MPa and liquid pressure of 0.25 MPa. This precision liquid pollination device is advantageous for precise control under high pressure and low flow conditions, suitable for the end effector of autonomous pollination robots. The optimization and evaluation methods established within this study provide reference for the development of precision pollination devices.

Droplet characteristics of multi-plume flash boiling spray evaluation using SLIPI-LIEF/Mie planar imaging technique

Flash boiling atomization is a promising approach whose primary breakup heavily relies on the phase change inside the nozzle. Droplet size measurement is crucial for fundamental studies of flash boiling sprays. However, the interference of the vapor phase and multiple scatterings in droplet-dense regions notably impact the accuracy of spray droplet size measurement. In this work, we utilized a three-phase structured laser illumination planar imaging, laser-induced exciplex fluorescence/Mie scattering (3p-SLIPI-LIEF/Mie) method in evaluating the droplet size distribution for a two-hole fuel injector and an ECN Spray G injector. The SMD characteristics of the fuel spray under various temperature and pressure boundary conditions were examined, and flash boiling spray collapse conditions were emphasized. The results show that the proposed SLIPI-LIEF/Mie method is superior to PDI techniques in providing more comprehensive results while maintaining satisfactory accuracy. The SLIPI-LIEF/Mie results show that the near-field plume expansion and SMD distribution strongly correlate with the flash boiling phase transition process. The droplet in the collapsed region was larger than that in the primary plume regions. However, whether or not the spray collapses, the SMD of the spray reduces as the fuel temperature increases, ambient pressure decreases, and injection pressure increases.

A novel microfluidic method to simultaneously measure droplet size and interfacial tension without visualization

AbstractDroplet size and interfacial tension are key parameters related to two‐phase flow. However, current methods for measuring these parameters are usually based on visualization and are therefore not applicable for invisible two‐phase flow systems. Moreover, real‐time determination of interfacial tension is difficult because conventional methods cannot be employed in the flow field. This study presents a novel method for simultaneously measuring the droplet size and real‐time interfacial tension in a two‐phase flow system. A T‐shaped microdevice was designed and integrated with the two‐phase flow equipment. The pressure variation as the droplets flowed through the microdevice was used as a probe to detect the two key parameters, that is, visualization is not required. Monodispersed and multidispersed droplet flows in different equipment were used to verify the method. Both the droplet size distribution and real‐time interfacial tension can be determined using the developed approach.

Investigation of the Artificial Saliva and Saline Droplet Size Measurement Accuracy for COVID-19 Infection Control

Investigation of the Artificial Saliva and Saline Droplet Size Measurement Accuracy for COVID-19 Infection Control

Impact mechanism of methylation degree on structure and emulsifying ability of soy hull polysaccharides

As a chemical modification method, methylation may enhance the emulsification of polysaccharides. In this study, we methylated soy hull polysaccharide (SHP) at 60 °C for 0–8 h and analyzed the degree of methylation (DM), crystallinity, surface hydrophobicity, interfacial adsorption, and emulsification capacity of methylation-modified SHP (MSHP). Fourier infrared spectroscopy results showed that the DM changed from 41.48% ± 1.46%–58.30% ± 2.63% after 8 h of methylation (MSHP-8h). The polysaccharide residues were analyzed by 1H NMR. Increasing the DM improved the surface hydrophobicity of SHP, which effectively reduced the interfacial tension (IFT) of SHP at the O/W interface. At equilibration, the IFT was the lowest for MSHP-8h (15.40 mN/m). However, interface thickness was negatively correlated with the DM. Methylation promotes the migration of SHP to the oil side; therefore, the polysaccharide layer remaining in the aqueous phase decreases with an increasing DM at low and fixed SHP concentration. A reduction in hydrophilicity weakens the hydrogen bonds between polysaccharides to cause the polysaccharide layer to be easily destroyed during the dilution process of the droplet size measurement. However, thin adsorption or hydration layers can adversely affect the stability of the interfacial layer; consequently, emulsions prepared with MSHP-4h were the most stable. Our findings provide a practical and theoretical reference for improving emulsification ability of polysaccharides.

Formulation Development and Evaluation of Apremilast Nanoemulsion

Apremilast is a selective phosphodiesterase 4 inhibitor administered orally in the treatment of moderate-to-severe plaque psoriasis and active psoriatic arthritis. It is classified as class IV drug as per BCS classification so it indicates low solubility and lower permeability through the skin. Therefore the objective of the research is to improve permeability of Apremilast through the skin and improve solubility by using oil and surfactant by formulating Nanoemulsion. Nanoemulsion was prepared by selecting Captex 355, Cremophore RH 40, Labrafil and Propylene glycol as the oil, surfactant,co-surfactant and co-solvent respectively after solubility study. Pseudo-ternary phase diagrams were constructed to find out the optimum ratio of oil: Smix (surfactant: co-Surfactant). Simple lattice design was applied to the optimization of the prepared nanoemulsion. The nanoemulsion was evaluated for Physical parameter, pH, Droplet size, zeta potential, in-vitro diffusion study etc. Results of Droplet size measurements, zeta potential and % drug diffusion indicated A5 batch optimized batch than other formulation of the nanoemulsion. So, optimized formulation further tested for Skin irritation study and stability study.The Apremilast loaded stable Nanoemulsion system was prepared and various process variables were evaluated. Batch A5 was selected as an optimized batch containing 10 % Captex 355, 40 % Smix (Cremophore RH 40 and Labrafil) and 50% water. Optimized batch was found to be stable after three month at ambient condition of temperature and humidity, giving reproducible results when evaluated.

Validation of the CFD Tools against In-House Experiments for Predicting Condensing Steam Flows in Nozzles

The issues addressed in this work concern the condensing steam flows as a flow of a two-phase medium, i.e., consisting of a gaseous phase and a dispersed phase in the form of liquid droplets. The two-phase character and the necessity to treat steam as a real gas make the numerical modeling of the flow in the last steam turbine channels very difficult. There are many approaches known to solve this problem numerically, mainly based on the RANS method with the Eulerian approach. In this paper, the two Eulerian approaches were compared. In in-house CFD code, the flow governing equations were defined for a gas–liquid mixture, whereas in ANSYS CFX code, individual equations were defined for the gas and liquid phase (except momentum equations). In both codes, it was assumed that there was no velocity slip between phases. The main aim of this study was to show how the different numerical schemes and different governing equations can affect the modeling of wet steam flows and how difficult and sensitive this type of computation is. The numerical results of condensing steam flows were compared against in-house experimental data for nozzles determined at the Department of Power Engineering and Turbomachinery of the Silesian University of Technology. The presented experimental data can be used as a benchmark test for researchers to model wet steam flows. The geometries of two half nozzles and an International Wet Steam Experimental Project (IWSEP) nozzle were used for the comparisons. The static pressure measurements on the walls of the nozzles, the Schlieren technique, and the droplet size measurement were used to qualitatively identify the location of the condensation onset and its intensity. The CFD results obtained by means of both codes showed their good capabilities in terms of proper prediction of the condensation process; however, there were some visible differences in both codes in the flow field parameters. In ANSYS CFX, the condensation wave location in the half nozzles occurred much earlier compared to the experiments. However, the in-house code showed good agreement with the experiments in this region. In addition, the results of the in-house code for the mean droplet diameter in the IWSEP nozzle were closer to the experimental data.

Effects of Salinity Beyond Coalescence on Submicron Aerosol Distributions

AbstractBubbles entrained by ocean waves rise to the surface and burst, creating a shower of droplets which contribute to sea spray aerosols. Submicron‐sized droplets, of which an estimated 60%–80% come from a bursting bubble film cap, play a key role in global climate atmospheric processes. However, many aspects of predicting the number and size of submicron drops emitted from a bursting bubble remain unknown. It is well‐documented that higher salinity increases submicron droplet production, which has been attributed to the role of salt in the suppression of bubble coalescence. We experimentally show that submicron drop production increases with salinity despite using a salt that does not affect bubble coalescence, indicating that salinity plays a role in the physics of submicron aerosol formation beyond coalescence. Laboratory experiments are conducted using sodium acetate solutions of salinity S = 0.001–0.1 M with millimeter‐sized bubbles generated via a needle. Unlike previous studies, the measured droplet size distributions are converted to formation diameter, revealing that the peak aerosol formation diameter decreases with higher salinity. Applying this diameter conversion to past studies, we find the peak formation diameter exhibits a scaling of Dform ∼ S−0.32 across three orders of magnitude in salinity and for a variety of salts, bubble coalescence behaviors, and bubble generation mechanisms. This result suggests that salinity has a systematic effect on the length scale of the rupturing bubble film which generates the aerosols. Consequently, salinity likely impacts the submicron aerosol production in oceanic environments even if bubble coalescence is negligible.

Effects of H.uvarum combined with KGM on postharvest diseases of blueberry

The aim of this work was to evaluate the efficacy of an innovative edible coating that combines Hanseniaspora uvarum and konjac glucomannan to preserve blueberries. The antagonistic yeast and four main fungi (Aspergillus niger, Penicillium, Alternaria alterniformis, Pseudomonas spp.) isolated from blueberry pathogens were subjected to in vitro antibacterial experiments, and the optimal concentration of antagonistic yeast was determined as 1 × 108 CFU/mL. The antibacterial mechanism of yeast against pathogenic fungi was characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, viscometry, measurement of electrospray droplet size and coating thickness. Finally, the resulting spray was used to treat blueberry wound rot and to store blueberries. After 14 days of storage, the konjac glucomannan/Hanseniaspora uvarum composite coating solution was found to be more effective in maintaining blueberry quality compared with the control and konjac glucomannan groups.

Comparison between shadow imaging and in-line holography for measuring droplet size distributions

A direct comparison of the droplet size and number measurements using in-line holography and shadow imaging is presented in three dynamically evolving laboratory scale experiments. The two experimental techniques and image processing algorithms used to measure droplet number and radii are described in detail. Droplet radii as low as r = 14 µm are measured using in-line holography and r = 50 µm using shadow imaging. The droplet radius measurement error is estimated using a calibration target (reticle) and it was found that the holographic technique is able to measure droplet radii more accurately than shadow imaging for droplets with r le 625 µm. Using the measurements of droplet number and size we quantitatively cross-validate and assess the accuracy of the two measurement techniques. The droplet size distributions, N(r), are measured in all three experiments and are found to agree well between the two measurement techniques. In one of the laboratory experiments, simultaneous measurements of droplets (r ge 14 µm, using holography) and dry aerosols (0.07 lessapprox r lessapprox 2 µm, using an scanning mobility particle sizer and 0.15 lessapprox r lessapprox 5 µm using an optical particle sizer) are reported, one of the first such comparison to the best of our knowledge. The total number and volume of droplets is found to agree well between both techniques in the three experiments. We demonstrate that a relatively simple shadow imaging technique can be just as reliable when compared to a more sophisticated holographic measurement technique over their common droplet radius measurement range. The agreement in results is shown to be valid over a large range of droplet concentrations, which include experiments with relatively sparse droplet concentrations as low as 0.02 droplets per image. Advantages and disadvantages for the two techniques are discussed in the context of our results. The main advantages to in-line holography are the greater accuracy in droplet radius measurement, greater spatial resolution, larger depth of field, and the high repetition rate and short pulse duration of the laser light source. In comparison, the main advantages to shadow imaging are the simpler experimental setup, image processing algorithm, and fewer computer resources necessary for image processing. Droplet statistics like number and size are found to be very reliable between the two methods for large range of droplet densities, {mathcal {P}}_{r>50}, ranging from 10^{-4} le {mathcal {P}}_{r>50} le 10^{-1} cm^{-3}, when the two techniques are implemented as shown in this paper.

Theoretical and experimental studies on the oil-based emulsion spray.

Oil-based emulsion is a common herbicide formulation in agricultural spray, and its atomization mechanism is different from that of water spray. In this paper, a theoretical model based on the characteristics of spray sheets was proposed to predict the spray droplet size for oil-based emulsion spray. An image processing method was used to measure droplet size distributions for different spray pressures and nozzle configurations, and the measured results were used to validate the theoretical model. The results show that oil-based emulsion spray is characterized by the web structure constituted by perforations. The liquid originally occupied by spray sheets eventually gathers in these web structures. The proposed theoretical model is based on the size of the nozzle exit, the angle of spray sheets, and the perforation number in the web structure, which are relatively easy to obtain. The theoretical droplet size is in inverse proportion to the square root of the perforation number in the web structure while in proportion to the square root of the area of the nozzle exit. The captured images of spray sheets and the measured droplet size distribution show consistency with the theoretical prediction. The difference between theoretical results and measured volumetric median diameter is less than 10% for different spray pressures and nozzles.

Improved electro-optical and dielectric properties of polymer dispersed liquid crystal doped with disperse dye red 1 and carbon nanoparticles

ABSTRACT Disperse dye red 1 (DR1) and carbon nanoparticles (CNPs) were doped separately to form polymer dispersed liquid crystal films, namely, DPDLC & CPDLC. Nematic liquid crystal (LC) and photopolymer NOA-65 were used to prepare these composite films using polymerisation-induced phase separation (PIPS) technique. In this research work, it is demonstrated that the minute concentration (0.05% wt./wt.) of DR1 and CNPs controls the LC droplet alignment and LC droplet size in polymer dispersed liquid crystal (PDLC) film. The effect of DR1 and CNPs on PDLC film has been investigated in terms of LC droplet size, transition temperature, voltage-transmittance characteristic, contrast ratio, response time, haze, and dielectric measurements. The obtained results reveal that the threshold voltage values of the composite film get reduced from 34.87 V (undoped) to 10.19 and 9.26 V, for 0.05% of DR1 and CNPs doping, respectively. The DR1 (0.05%) doped film shows improved contrast of the undoped film as compared to CNPs (0.05%) film, whereas CNPs (0.05%) doped film shows a faster response time of 2.81 ms as compared to DR1 (0.05%) doped film (3.14 ms). Dielectric analysis of undoped, DPDLC, and CPDLC films represents Debye type relaxation mode.

Enhanced Bioactivity of Rosemary, Sage, Lavender, and Chamomile Essential Oils by Fractionation, Combination, and Emulsification.

This study aimed to increase the bioactivity of essential oils by fractionation, combination, and emulsification. In this regard, pharmaceutical quality Rosmarinus officinalis L. (rosemary), Salvia sclarea L. (clary sage), Lavandula latifolia Medik. (spike lavender), and Matricaria chamomilla L. (chamomile) essential oils were fractionated by vacuum-column chromatography. The main components of the essential oils were verified, and their fractions were characterized by thin layer chromatography, gas chromatography-flame ionization detector, and gas chromatography/mass spectrometry. Besides, oil-in-water (O/W) emulsions of essential oils and diethyl ether fractions were obtained by the self-emulsification method, followed by droplet size, polydispersity index, and zeta potential value measurements. The in vitro antibacterial effects of the emulsions and binary combinations (10:90, 20:80, 30:70, 40:60, 50:50, 60:40, 70:30, 80:20, 90:10, v:v) against Staphylococcus aureus were determined by microdilution. In addition, the in vitro anti-biofilm, antioxidant, and anti-inflammatory effects of emulsion formulations were evaluated. According to the experimental results, fractionation and emulsification enhanced essential oil in vitro antibacterial, anti-inflammatory, and antioxidant effects due to increased solubility and nano-sized droplets. Among 22 different emulsion combinations, 1584 test concentrations resulted in 21 cases of synergistic effects. The mechanism of the increase in biological activities was hypothesized to be higher solubility and stability of the essential oil fractions. Food and pharmaceutical industries may benefit from the procedure proposed in this study.

Object tracking based droplet characterization of high flowrate electrospray

Electrospray was applied to the wet electrostatic precipitator to reduce the water consumption of high-efficiency fine dust collection. The size of droplets must be large to avoid evaporating quickly under high temperature exhaust gas conditions, so a high flow rate condition of several milliliters/min is used, which is relatively high compared with previous applications. Because a high flow rate electrospray has a wide spray range and a low spray density, image-based droplet size measurement was used. A bias in the probability in the distribution occurs because of the difference in velocity between the droplets. In this study, an approach with object tracking was suggested to eliminate the bias from velocity differences. High flow rate electrospray droplets under various voltage conditions were visualized with a high-speed camera. Based on the image processing, the corrected distribution was characterized, and the effect of the bias was established through comparison with the general distribution. In addition, the spray pattern and the droplet distribution according to the applied voltage of three spraying modes were analyzed. Improved analysis of the actual spray using this approach will guide the selection of operating conditions that optimize dust collection efficiency.