Initial Spray Research Articles

Fine-grained method for determining size and velocity distribution patterns of flat-fan nozzle-atomised droplets based on phase doppler interferometer

Pesticides are commonly applied by using agricultural nozzles to generate droplets during delivery process. Initial spray atomization characteristics including droplet size and velocity are important factors that affect the pesticide utilization rate. Exploring efficient methods for atomization measurement is helpful to deeply understanding nozzle sprays. In this study, droplet size and velocity of a flat-fan nozzle were measured with phase doppler interferometry (PDI), and sub-area statistics method was adopted to establish a fitting model for atomization characteristics analyse. The results demonstrated that the distribution patterns and value contrasts of droplet size and velocity in different sub-areas visually reflect the nozzle atomization characteristics under varying spray pressures. The quantized model of droplet size and velocity within spatial sub-areas of spray atomization revealed significant differences in droplet size and velocity at various positions within the atomization area. Near the edge of the initial atomization zone, droplet size increases while velocity exhibits a decreasing trend. Additionally, the coefficient of determination for the x-axis position within the atomization zone, in relation to droplet size and velocity, was above 90%. The PDI with the sub-area statistical method employed in this study offers a fine-grained approach for investigating nozzle atomization characteristics.

Novel insights from agricultural waste to acetic acid through regulated high-solids anaerobic digestion: Focus on the key microbial communities

Acetic acid (HAc) is an essential intermediate for improving the efficiency of biogas production in anaerobic digestion (AD) or for the production of liquid chemicals. The relationships between the mechanisms and microbial contributions of targeted regulation of HAc production in high-solids AD remains unclear. This study represents a breakthrough in revealing the mechanism of pH directed regulation of HAc production and microbial interactions. The regulation of the initial spray pH effectively improved the substrate hydrolysis rate and increased the concentration of HAc, with an average HAc percentage of total organic acids was 66.20 %. Microecological analysis revealed that rare species played a vital role in acidification, with all key acetogenic microbes identified as rare species. Additionally, the construction of a bacterial–environmental factor co-occurrence network revealed that lowering the initial spray pH enhanced the synergistic interactions among bacterial communities, and proportion of positive interactions among bacteria was 82.23 %. The gene abundance of key enzymes in the acetate-type metabolic pathway dominated in the acidogenesis phase. Furthermore, a regression model was established between the HAc indicator microbe (Acinetobacter) and HAc yields. Overall, the results of this study indicate that pH regulation plays an important role in strengthening the production of HAc and rare species significantly contributed to HAc production.

Effects of Nozzle Retraction Elimination on Spray Distribution in Middle-Posterior Turbinate Regions: A Comparative Study.

The standard multi-dose nasal spray pump features an integrated actuator and nozzle, which inevitably causes a retraction of the nozzle tip during application. The retraction stroke is around 5.5 mm and drastically reduces the nozzle's insertion depth, which further affects the initial nasal spray deposition and subsequent translocation, potentially increasing drug wastes and dosimetry variability. To address this issue, we designed a new spray pump that separated the nozzle from the actuator and connected them with a flexible tube, thereby eliminating nozzle retraction during application. The objective of this study is to test the new device's performance in comparison to the conventional nasal pump in terms of spray generation, plume development, and dosimetry distribution. For both devices, the spray droplet size distribution was measured using a laser diffraction particle analyzer. Plume development was recorded with a high-definition camera. Nasal dosimetry was characterized in two transparent nasal cavity casts (normal and decongested) under two breathing conditions (breath-holding and constant inhalation). The nasal formulation was a 0.25% w/v methyl cellulose aqueous solution with a fluorescent dye. For each test case, the temporospatial spray translocation in the nasal cavity was recorded, and the final delivered doses were quantified in five nasal regions. The results indicate minor differences in droplet size distribution between the two devices. The nasal plume from the new device presents a narrower plume angle. The head orientation, the depth at which the nozzle is inserted into the nostril, and the administration angle play crucial roles in determining the initial deposition of nasal sprays as well as the subsequent translocation of the liquid film/droplets. Quantitative measurements of deposition distributions in the nasal models were augmented with visualization recordings to evaluate the delivery enhancements introduced by the new device. With an extension tube, the modified device produced a lower spray output and delivered lower doses in the front, middle, and back turbinate than the conventional nasal pump. However, sprays from the new device were observed to penetrate deeper into the nasal passages, predominantly through the middle-upper meatus. This resulted in consistently enhanced dosing in the middle-upper turbinate regions while at the cost of higher drug loss to the pharynx.

Experimental investigation of air step cooling by the combination of spray and chord grid for mine cooling

To address the issues of heat and humidity hazards, as well as insufficient air volume in deep mining operations, a novel cooling method combining spray and chord grid is proposed. To investigate the cooling dynamics, an experimental platform integrating both spray and chord grid components is independently developed. Field boundary conditions are simulated to conduct orthogonal experimental research. Under the experimental parameters of an inlet air temperature of 32 °C, relative humidity of 88 %, and initial spray water temperature of 26 °C, the effects of water-air ratio, nozzle distance, and other parameters on inlet and outlet temperature, as well as moisture content, are quantified. These influencing factors are analyzed through range analysis. Results demonstrate that the water-air ratio has a greater impact on cooling compared to the nozzle distance. Notably, when the water-air ratio and nozzle distance reach critical values of 0.6 and 70 cm respectively, the cooling rate begins to plateau. Furthermore, comparative analysis of the cooling and dehumidification effects of single spray versus spray + chord grid reveals that the cooling capacity of single spray systems can be surpassed by incorporating a chord grid. Specifically, the combination of spray + chord grid achieves superior cooling effects with lower water consumption.

Potential Analysis of Defossilized Operation of a Heavy-Duty Dual-Fuel Engine Utilizing Dimethyl Carbonate/Methyl Formate as Primary and Poly Oxymethylene Dimethyl Ether as Pilot Fuel

<div>This study demonstrates the defossilized operation of a heavy-duty port-fuel-injected dual-fuel engine and highlights its potential benefits with minimal retrofitting effort. The investigation focuses on the optical characterization of the in-cylinder processes, ranging from mixture formation, ignition, and combustion, on a fully optically accessible single-cylinder research engine. The article revisits selected operating conditions in a thermodynamic configuration combined with Fourier transform infrared spectroscopy.</div> <div>One approach is to quickly diminish fossil fuel use by retrofitting present engines with decarbonized or defossilized alternatives. As both fuels are oxygenated, a considerable change in the overall ignition limits, air–fuel equivalence ratio, burning rate, and resistance against undesired pre-ignition or knocking is expected, with dire need of characterization.</div> <div>Two simultaneous high-speed recording channels granted cycle-resolved access to the natural flame luminosity, which was recorded in red/green/blue and OH chemiluminescence.</div> <div>Selected conditions were investigated in more detail with the simultaneous application of planar laser-induced fluorescence of OH and HCHO and recording natural flame luminescence in a cycle-averaged manner.</div> <div>Poly oxymethylene dimethyl ether was used as pilot fuel, building on prior investigations. The mixture of 65 vol% Dimethyl Carbonate and 35 vol% Methyl Formate with prior verification on a passenger-car-sized engine substitutes synthetic natural gas in this study.</div> <div>Thermodynamically, the increased compression ratio up to 17.6 resulted in feasible operation and increased indicated efficiency. On the lower compression ratio of 15.48, a more comprehensive range of applicable air–fuel equivalence ratios and increased degrees of freedom regarding the pilot’s total energy share are observed compared to the base configuration with natural gas and EN590 as pilot fuel.</div> <div>The air–fuel equivalence ratio sweep from λ = 1.0–2.0 revealed predominantly premixed and high-temperature heat release via OH*. The temporal and spatial evolution shifts while leaning out the mixture with increasing gradients on the radial distribution and decouples for lean mixtures from the initial spray trajectory.</div>

Effects of step hole geometry and spray-wall interactions on spray atomization in LPDI injector

The study aims to analyze the spray atomization of liquefied petroleum gas direct injection (LPDI) injector based on the macroscopic and microscopic experiments. Two experimental injectors were used in the presence and absence of step hole, and the experimental fuels used n-heptane and n-butane.The macroscopic and microscopic spray characteristics as function of the application of step hole were analyzed using two experimental injectors and n-heptane fuel. The macroscopic spray experiments analyzed the initial spray, after the end of injection and nozzle tip wetting using near-field visualization, and microscopic spray experiment analyzed fuel–air atomization phenomenon as function of the application of step hole using PDPA equipment.In addition, macroscopic and microscopic spray characteristics were analyzed for two experimental fuels and spray-wall impingement using the presence of step hole injector. The macroscopic spray experiment analyzed the spray evaporation characteristics for the two experimental fuels and spray-wall impingement using the schlieren visualization, and microscopic spray experiment analyzed the fuel–air atomization phenomenon as function of the two experimental fuels and spray-wall impingement using PDPA equipment.It was found that the presence of step hole injector showed better atomization results than those of the absence of step hole injector. But, the tip wetting of the presence of step hole injector was poor than that of the absence of step hole injector. Furthermore, based on the schlieren experiment, a comparison of free and flat sprays with the two fuels found that the spray width and area of n-heptane in free spray exceeded those of n-butane owing to the vapor pressure of n-butane. However, in the flat spray, the spray width and area of n-butane were exceeded those of n-heptane. It was found that the atomization was promoted after the spray-wall impingement.

Development and validation of a product acceptability questionnaire for intranasal Q-Griffithsin COVID-19 prophylaxis (SPRAY PAL)

ObjectivesPatient experiences are critical when determining the acceptability of novel interventional pharmaceuticals. Here, we report the development and validation of a product acceptability questionnaire (SPRAY PAL) assessing feasibility, acceptability and...

Multiple structures and transition mechanisms of laminar fuel-rich ethanol/air counterflowing spray flames

Structures of laminar non-premixed ethanol/air spray flames in the axisymmetric counterflow configuration are studied under fuel-rich conditions by means of numerical simulations. The monodisperse ethanol spray is carried by air and directed against an air stream. Both streams enter at 300 K, and the system is at atmospheric pressure. Up to three different structures of these flames for identical boundary and initial conditions are identified, and regime diagrams are presented that show their conditions of existence in terms of the gas strain rate on the spray side of the configuration, [Formula: see text], starting from 55/s at an initial spray velocity of 0.44 m/s. The equivalence ratio on the spray side, [Formula: see text], is varied between 1.1 and 1.6, and initial droplet radii, [Formula: see text], from 10 to 50 [Formula: see text]m are considered. The most stable spray flame structure is characterized by two chemical reaction zones. For some conditions, single chemical reaction zones on either side of the counterflow configuration are found. Conditions under which these different flame structures exist are analyzed. Previous studies identified only two different structures for non-identical boundary conditions, and in this study, three different structures are presented for the first time. Moreover, the transition mechanisms of one structure to another are analyzed. The competition between the energy-consuming spray evaporation and the exothermic chemical reaction rates as well as the location of the spray determines the existence of the different flame structures. This transition of the different flame structures may explain spray flame characteristics such as flame pulsation or flame instabilities.

Assessment of microbial biocontrol agents (BCA) viability to mechanical and thermal stress by simulating spray application conditions.

To improve the biological control agent (BCA) efficacy, stress factors threatening the microorganisms viability during spray application need to be determined. The effect of spray mixture temperature and exposure time on Trichoderma harzianum T 22 and Bacillus amyloliquefaciens QST713 viability were tested. Concurrently the combined effect of mechanical and thermal stress effect on BCAs viability were tested at two initial spray mixture temperatures (14°C and 25°C) by simulating a spray application using airblast sprayers featured by different tank capacity and a spray liquid circuit (without and with hydraulic agitation system). To assess the BCA microorganisms viability, spray mixture samples were collected at time intervals along trials and plated to count the colony forming units (CFU). The critical temperature threshold that inhibited BCA viability was 35°C with 30 min of exposure. The sprayer type, the initial temperature of the spray mixture and the temperature increment during the trials significantly decreased the number of the CFU recovered. When simulating a spray application, the spray mixture temperature increasing rate was mainly determined by the residual amount of spray mixture in the tank. Even if the tank capacity does not substantially affect the final temperature reached by the spray mixture, the higher residual spray mixture in bigger tanks can expose the BCA for a longer time to critical temperatures. Experimental trials allowed to identify the effect of factors affecting the viability of tested BCA, providing information about the actual chance to guarantee the biological efficacy of BCA treatments. This article is protected by copyright. All rights reserved.

Recovery of upland acid grasslands after successful Pteridium aquilinum control: Long-term effectiveness of cutting, repeated herbicide treatment and bruising

There is a clear need for the development of management strategies to control dominant, perennial weeds and restore semi-natural communities and an important part of this is to know how long control treatments take to be effective and how long they last after treatments stop. Here, we report the results from a 17-year long experiment where we compared the effects of five control treatments on dense Pteridium aquilinum (L. Kuhn) relative to an untreated experimental-control in Derbyshire, UK. The experiment was run in two phases. In Phase 1 (2005–2012) we controlled the P. aquilinum by cutting and bruising, both twice and thrice annually, and a herbicide treatment (asulam in year 1, followed by annual spot-re-treatment of all emergent fronds). In Phase 2 (2012–2021) all treatments were stopped, and the vegetation was allowed to develop naturally. Between 2005 and 2021 we monitored P. aquilinum performance annually and full plant species composition at intervals. Here, we concentrate on analysing the Phase 2 data where we used regression approaches to model individual species responses through time and unconstrained ordination to compare treatment effects on the entire species composition over both Phases. Remote sensing was also used to assess edge invasion in 2018.At the end of Phase 1, a good reduction of P. aquilinum and restoration of acid-grassland was achieved for the asulam and cutting treatments, but not for bruising. In Phase 2, P. aquilinum increased through time in all treated plots but the asulam and cutting ones maintained a much lower P. aquilinum performance for nine years on all measures assessed. There was a reduction in species richness and richness fluctuations, especially in graminoid species. However, multivariate analysis showed that the asulam and cutting treatments were stationed some distance from the untreated and bruising treatments with no apparent sign of reversions suggesting an Alternative Stable State had been created, at least over this nine-year period. P. aquilinum reinvasion was mainly from plot edges.The use of repeated P. aquilinum control treatments, either through an initial asulam spray with annual follow-up spot-spraying or cutting twice or thrice annually for eight years gave good P. aquilinum control and helped restore an acid-grassland community. Edge reinvasion was detected, and it is recommended that either whole-patch control be implemented or treatments should be continued around patch edges.

Tablet coating in lab-scale drum coaters: Combining DEM simulations and spray experiments to predict tablet coating

In pharmaceutical industry the coating of granulates or tablets is an essential production step, which is often realised in a rotating drum moving the tablet bed and a number of spray nozzles installed above this bed. The nozzles atomise the coating liquid through a high-velocity annular air-stream and apply steering air nozzles for producing an oval-shaped spray. The operational conditions determine the produced droplet size spectrum. The collision of the droplets with the solid particles or tablets in the drum and the resulting coating and film thickness strongly influences the product properties of granulates or tablets. In order to be able to predict the coating result, without running time-consuming lab-scale experiments, it is intended to numerically simulate the entire tablet coating process by combining Computational Fluid Dynamics (CFD), the Discrete Element Method (DEM) and the Lagrangian Parcel Concept (LPC) for simulating the spray propagation originating at the nozzle. For doing so, knowledge on the spray droplet properties produced by the two-fluid spray nozzles is indispensable. Therefore, it is necessary to characterise as a first step the local droplet size and velocity distributions in different spray cross-sections, which is the main focus of the present contribution. Such measurements are efficiently done by applying Phase Doppler Anemometry (PDA). It was found that the velocity of the spray emitted from the two-fluid nozzle exceeds almost 200 m/s and the number mean droplet diameter was well below 20 μm. In the initial spray region droplet break-up was observed whereas downstream of 50 mm a slight growth of the mean droplet size indicated further coalescence. Due to the applied pattern air, the spray flux distribution at the normally located tablet bed (i.e., 100–150 mm downstream the nozzle) has an oval shape and the mean droplet velocity still exceeds almost 50 m/s with a mean droplet diameter of about 10 μm. The cross-sectional measurements are used to provide proper inlet conditions for the spray simulations, while the other cross-sections are used for validating the computed spray expansion and dispersion. For demonstrating the effect of a real measured spray flux distribution on the tablet coating quality, additionally DEM simulations were conducted. Here, the measured spray flux data were mapped onto the temporarily evolving and moving tablet surface simulated for a lab-scale test drum by DEM. The uniformity of tablet coating (inter-tablet variability) was judged by calculating the Coefficient Of Variation (COV) for the considered different tablet shapes and operational conditions.

Experimental investigation of the effect of duct structure geometry on macroscopic spray characteristics and air entrainment of duct fuel spray

The fuel–air mixing process can be improved via straight (ST) ducted fuel injection, but there is a risk of greater heat transfer loss due to prolonged spray tip penetration (STP) and spray impingement. In this study, we propose a convergent-divergent (CD) duct spray to produce an acceptable STP to improve the spray air entrainment (SAE) and spray cone angle (SCA). Three CD and two ST ducts were designed and installed in a constant-volume chamber. An optical Schlieren visualization system with a high-speed camera was used to examine the effects of duct geometry on the macroscopic spray parameters of SCA, STP, spray area (SA), SAE, and spray morphology. Compared with the free spray, the longest STP was noted for the ST2 duct spray, whereas the shortest STP was observed for the CD4.5 duct spray; the STP decreased by 14.5 %, whereas the SCA increased by at least two times for CD4.5 and CD6 duct sprays. A typical trade-off relationship between SCA and STP was confirmed for larger diameter CD duct sprays. When the injection pressure increased from 120 to 140 to 160 MPa, the STP of the ST2 duct spray increased by 1.7 % and 2.4 %, and that of the CD4.5 duct spray increased by 3.1 % and 7.0 %, respectively. At the late spray stage, the CD4.5 and CD6 duct spray had the better SAE ability, followed by the ST3 and CD3 duct sprays, ST2 duct spray exhibited slightly lower SAE values than the free spray. A typical mushroom-shaped spray head was observed near the outlet of the ST2 and ST3 duct sprays, while a cotton-shaped spray was observed for the CD duct sprays during the initial early spray stage. The development of the CD duct spray showed a left–right swing phenomenon with an S-shaped track, particularly for CD4.5 and CD6 duct sprays, which can promote the fuel–air mixing process with a larger SCA. The CD4.5 duct spray demonstrated considerable potential for improving the fuel–air mixture with a stronger SAE and larger SCA, as well as the ability to reduce the heat transfer loss with a shorter STP and weaker spray impingement.

Evaluation of multi-hole diesel injectors spray under evaporating conditions: Effects of adjacent spray plumes on the macroscopic and mixture characteristics of target spray

Previously, diesel sprays of multi-hole injectors were simulated in an environment where only a single spray plume was simulated. Although boundaries were declared as symmetry, the impact of aerodynamic forces between spray plumes was always neglected. In the present work, all spray plumes of diesel injectors are simulated in a cylindrical box mesh considering external effects including umbrella angle, space between nozzle holes, and hole length to hole diameter ratio. To examine the nozzle hole size effect, two 10-hole diesel injectors with hole diameters of 0.101 and 0.133 mm are investigated under 120 MPa injection pressure. Likewise, to understand the effect of injection pressure, the 0.101 mm hole diameter injector is studied under 120 and 140 MPa rail pressures. In experiments, Laser Absorption Scattering diagnostic technique is applied to visualize the vapor phase, measure mixture concentration and characterize air entrainment. Since Diesel fuel does not absorb UV light, Tracer fuel with the composition of 97.5% of n-tridecane and 2.5% α-Methylnaphthalene is used. On the contrary, sprays are simulated in the Eulerian-Lagrangian two-phase fluid framework using KHRT Breakup and Multicomponent Evaporation models. Parameters such as injection rate and initial spray trajectory angle are measured experimentally and used as input for the spray simulation. Computational results correspond with experiments particularly in terms of Penetration and Equivalence Ratio while Spray Angle deviates.

Effects of full transient Injection Rate and Initial Spray Trajectory Angle profiles on the CFD simulation of evaporating diesel sprays- comparison between singlehole and multi hole injectors

This paper investigates experimental and computational diesel sprays of single hole and multi hole injectors under vaporizing conditions. Two single hole and two ten-hole injectors with the same nozzle hole size are tested with the 120 MPa injection pressure. Experiments implement Laser Absorption Scattering technique. This method utilizes two wavelengths (Visible and Ultraviolet) of light and fuel's mixture concentrations are measured by attenuations of these lights. On the other hand, sprays are simulated in the Eulerian Langrangian two-phase fluid framework where KHRT and Multicomponent models are used as droplet breakup and evaporation models respectively. Full transient profiles of Injection Rate and Initial Spray Trajectory Angle are used as input boundary conditions for the spray simulation and effects on the spray characteristics are observed. Injection rates are measured with Bosch Long Tube and Initial Spray Trajectory Angles are extracted from the near nozzle field spray images. Experiments reveal that multi-hole injectors (0.101 mm and 0.133 mm) injectors depict longer liquid and shorter vapor penetrations. However, longer simulation liquid and vapor penetrations are seen for single hole injectors due to increased initial ramp-up phase. Sprays of Multi-hole injectors are diffused radially which promote air entrainment, better mixture formation, improved combustion, and lower exhaust emissions. Overall, simulated sprays using unfiltered injection rate profile as an input parameter showed an excellent agreement with experiments. While sprays using low-pass filtered injection rates showed a clear disagreement. Parameters including Liquid Length, Vapor Penetration and Evaporation ratios were found to be influenced by the IR profile rather than ISTA. Whereas vapor equivalence ratios depend on both input parameters plus breakup model constants.

Flow-field characteristics and ventilation performance of the high-temperature buoyant jet controlled by spray-local exhaust ventilation

High-temperature buoyant jets are common pollutants in hot-rolling plants. Owing to the constraints of the process equipment, local exhaust hoods cannot be set near the buoyant jet source, resulting in low ventilation efficiency and high energy consumption. To efficiently control the high-temperature buoyant jet, spray-local exhaust ventilation (SLEV) is used in this study. The aspects discussed the flow-field characteristics, ventilation performance and recommended optimization parameter order for initial spray droplet diameter, spray angle, and exhaust velocity. The results showed that when the initial droplet diameter was 50 μm ≤ D < 100 μm, the spray gained significant entrainment and cooling effect on the buoyant jet, and when it increased to 150 μm, the spray gained almost no effect. Besides, when the spray angle was 20°<α ≤ 80°, the control ability of the spray on buoyant jet was enhanced; when α ≤ 20°, it was difficult to control buoyant jet owing to the small coverage of the droplets. In addition, the spray helps the escaped buoyant jet to be captured by the exhaust hood. The capture efficiency of the SLEV was higher than that of the local exhaust ventilation (LEV) at the same exhaust velocity. Finally, the exhaust hood and spray parameters must be matched for efficient buoyant jet control since they are interactive. The interaction between the exhaust velocity and initial spray droplet diameter can exert a greater impact on the capture efficiency than the interaction between the exhaust velocity and spray angle. The research results provide guidance for the application of SLEV and reduce ventilation energy consumption.

Study on Influence Law of Key Factors of New Composite Slurry Spraying Technology

In this paper, a new type of water pressure and air pressure composite slurry is proposed to ensure the safety of spraying. Firstly, the air tightness, bending resistance and viscosity of the spraying material were measured in the laboratory. Secondly, the two-fluid VOF model was used to analyze the influence laws of the spraying process, the spraying area formed on the wall, the thickness of the spraying layer and the pressure at the nozzle (or initial flow rate), the spraying distance, the spraying time, and the spraying direction. The research shows that (1) the new composite slurry spraying material made of clay:cement:additive:engineering fiber = 84:14:1.85:0.15 has suitable sealing and bending resistance and adhesion. (2) The smaller the spraying distance is, the larger the spraying area formed on the side wall in a short time, and the shape is regular, but the spraying area is relatively small. The spraying area increases with the increase in spraying distance, and the slurry thickness becomes thinner with the increase in spraying distance. (3) When the initial spraying speed is high, the shape of the spraying area is regular, the spraying thickness is large and the uniformity is suitable, but the shape and uniformity of the spraying area are related to the time when the slurry reaches the side wall. The longer the time when the slurry reaches the side wall, the greater the influence of gravity and surrounding fluid, and the more changes along the process. (4) When the spraying surface is at the top, the spraying process is significantly affected by gravity, and discontinuous spraying areas will be formed on the top surface. Especially when the initial spraying speed is low, the amount of slurry reaching the top surface fluctuates due to rebound and increases with the increase in the initial spraying speed.

Resolving the initial spray structure of fire sprinklers with a volume-of-fluid modeling

The initial spray formation process of commercial fire sprinklers was investigated with a Large-eddy simulation and a Volume-of-Fluid model. The water-supply flow rate was set to 80 L/min corresponding to the minimum required flow rate in South Korea. From the study of grid dependency, a mesh size of 62.5 μm was adopted. Using this size of the mesh, unstable wave growth on the surface of the liquid sheet was captured, which corresponds to 1/16 the size of a sprinkler droplet that was derived in a previous study to be 1 mm. Sprinkler spray consisted of horizontal sheets generated by tines and vertical sheets generated by slots. Ligaments were produced by vortices on the air-water interface and droplets were generated by both longitudinal and lateral stretching. The flow rate of the tine section was larger than that of the slot section due to the large section angle. The water at the tine section was delivered to neighboring slot sections as flowing downstream. A formula for the sheet thickness was calibrated with measured mass outflow, which showed a more accurate value than the original formula driven by the mass conservation for the plate.

Identification of Two Fungal Pathogens Responsible for Liriodendron chinense × tulipifera Black Spot and Screening of Trichoderma sp. for Disease Control.

Liriodendron chinense × tulipifera black spot is a newly discovered disease that causes yellowing and early shedding of leaves, affecting the growth of Liriodendron trees, and significantly reducing their ornamental value as a garden species. The pathogen responsible for this disease, and how it can be prevented and controlled, are not clear. In this study, the occurrence of this disease was first investigated according to Koch's postulates, and the primary pathogens causing Liriodendron black spot were determined to be Colletotrichum gloeosporioides and Alternaria alternata. Biocontrol strains antagonistic to these two pathogens were then screened from the leaf microorganisms of L. chinense × tulipifera, and a preliminary investigation of the biological control of Liriodendron black spot was performed. Through the screening of antagonistic microorganisms on the leaf surface of L. chinense × tulipifera, the strain Trichoderma koningiopsis T2, which displayed strong antagonism against C. gloeosporioides and A. alternata, was obtained. The T2 strain could inhibit the growth of the two pathogens via three mechanisms: hyperparasitism, volatile and nonvolatile metabolite production, and environmental acidification. The biocontrol experiments in the greenhouse and field showed that initial spraying with a T. koningiopsis T2 spore suspension followed by the two pathogens resulted in the lowest disease incidence. These results confirmed the black spot pathogens of L. chinense × tulipifera, clarified the antagonistic mechanism of T. koningiopsis T2 against the two pathogens, and provided a theoretical basis and technical support for the biological control of the disease.

Spray characteristics from nasal spray atomization

In addition to topical delivery, nasal sprays offer an alternative drug administration route to the systemic circulation, therefore avoiding the need for painful, invasive delivery techniques. Studies on the efficacy of nasal drug delivery to date have been conflicting despite its potential. In particular computational studies, e.g. Computational Fluid Dynamics (CFD), of nasal spray deposition require realistic initial spray conditions, which are lacking in the literature. This study aims to provide benchmark experimental data for CFD inputs by characterizing four different types of commercially available nasal sprays used in an ENT (Ear Nose Throat) clinic. Spray characteristics were obtained via high-speed videography, while droplet size distribution (DSD) measurements were obtained with laser diffraction. Three actuation forces were evaluated, representing the use-case of an average adult, average child and the maximum force applied to the spray device. The results demonstrated that actuation force influenced spray velocity, spray duration, DSD, and breakup length. Quantitative data of Rosin–Rammler diameter distributions, spray cone angles, dispersion angles and breakup lengths were found, assisting computational models with realistic values, thereby improving future CFD studies of nasal spray drug delivery in the nasal cavity.

Novel insights from lignocellulosic waste to biogas through regulated dry-wet combined anaerobic digestion: Focusing on mining key microbes

Dry-wet combined anaerobic digestion is a novel approach for treating lignocellulosic waste by increasing the organic load of reactor while accelerating the conversion of organic acids. Here, we investigated the effect of regulated substrate ratios and initial pH in the dry acidogenesis stage on the bioconversion efficiency of dry-wet combined anaerobic digestion. Our data revealed microbial interactions and further identified key microbes based on microbial co-occurrence network analysis. On day three of acidification, the kinetic hydrolysis rate and acidification yield reached 1.66 and 60.07%, respectively; this was attributed to enhancement of the synergistic effect between Clostridiales and Methanosaeta, which increased the proportion of corn straw in the substrate or lowered the initial spray slurry pH to 5.5–6.5. With increased acidification capacity, acetoclastic methanogens were enriched in the wet methanogenesis stage; the syntrophic effect of Syntrophomonadales, Syntrophobacterales and Methanospirillum, meanwhile, was enhanced, leading to an overall improvement in biogas production.