Spray Volume Research Articles

The effects of sub/supercritical conditions on the spray interface characteristics of alkane fuel

ABSTRACT Alkane fuels are widely used in engines. The spray characteristics in supercritical environments are very different than in subcritical environments, and supercritical environments significantly impact the formation of the gas mixture in the engine. In this paper, the spray images of n-heptane and n-tetradecane in subcritical (500K-2MPa) and supercritical (700K-4MPa, 800K-6MPa) environments were obtained on the constant volume spray test platform. The effects of the supercritical environment and carbon chain length of alkane fuel on spray characteristic parameters were investigated. The results showed that the carbon chain length and ambient pressure are the main factors of penetration. The ambient pressure is the main factor of the spray cone angle and the spray non-liquid layer thickness. Compared with n-heptane, in the 500K-2MPa (subcritical) environment, the cone angle of n-tetradecane was reduced by 2°, the penetration was increased by 10 mm, and the spray non-liquid layer thickness was reduced by about 1 mm. In the 800K-6MPa (supercritical) environment, the cone angle of n-tetradecane was increased by 2°, the penetration was increased by 10 mm, and the spray non-liquid layer thickness was increased by about 1.2 mm. In addition, the calculation model of alkane fuel spray penetration in sub/supercritical environments was modified and achieved 95% prediction accuracy.

Spraying coupled with turbulence mechanisms enhanced the removal of fine particles in wet flue gas

Agglomeration pretreatment has been proved as the most effective method to enhance the removal of fine particulate matters (PM2.5). However, the common technologies were not suitable for the high-humidity conditions, such as the wet flue gas after desulphurization. Herein, we proposed a method for enhancing the agglomeration of fine particles by applying the combination mechanisms of spraying and turbulence effects. Through the experiments and simulation studies, we found that the number concentration proportions of fine particles can decrease by 19.9% in the size range of 0–0.5 μm, and increased by 15.2% in the range of 0.5–3.0 μm with the spray volume of 15 L/min. The turbulence effects can make the movement states of fine particles more disordered, and increase the collision and agglomeration opportunities among particles and droplets. The average particle size can be increased by 35% with the integrated turbulence structures and spraying. Combined with the agglomeration system, the graded removal efficiency of fine particles with the size of below 1.0 μm in WESP can be improved by 15%. This study contributes to comprehend the mechanism of turbulence on the particle agglomeration, and provides a reference for the upgradation and transformation of the existing dust removal equipment.

Performance of Drift-Reducing Nozzles in Controlling Small Weed Seedlings with Contact Herbicides

In many EU countries, spray applications should comply with increasingly stringent requirements regarding the drift reduction class of spray nozzles. Many farmers fear that the use of drift-reducing nozzles producing coarse droplet spectra may compromise the performance of contact herbicides on small weed targets. This study examined the effects of various ISO 03 drift-reducing flat-fan nozzles (pre-orifice and single and dual flat-fan air induction nozzles) differing in spray drift reduction class and spray pressure (2.5 bar, 5.0 bar) on (1) spray coverage, (2) droplet characteristics and (3) efficiency of contact herbicides bentazon and phenmedipham against cotyledon and 2-leaf stage plants of Chenopodium album and Solanum nigrum. Performance was compared to that of an ISO 03 standard flat-fan nozzle producing a finer droplet size spectrum. All sprayings were performed at a spray volume of 200 L ha−1. In most dose–response experiments, several drift-reducing flat-fan nozzles performed equally well as standard flat-fan nozzles, regardless of herbicide, spray pressure, growth stage or weed species. However, droplet size spectra of air-induction nozzles were too coarse for an adequate spray coverage and efficient application of contact herbicides on cotyledon stage plants of S. nigrum. In addition, the performance of air-induction nozzles in controlling difficult-to-wet C. album weeds with phenmedipham was better at 5.0 bar than at 2.5 bar. In contrast with droplet size characteristics, spray coverage characteristics determined on water sensitive papers were not good proxies for estimating the biological efficiency of contact herbicides. Air induction nozzles at 5.0 bar allow efficient control of 2-leaf targets, but nozzles emitting finer droplet spectra, such as pre-orifice nozzles, should be preferred for controlling cotyledon stage weeds at low-herbicide doses.

车载式施肥喷药机的设计与试验研究

In order to solve the problems of low efficiency of fertilization and spraying in the hilly mountains of China, a vehicle-mounted fertilization and spraying machine was designed. The whole structure and working principle of the machine were described, and the key components of fertilization and spraying are designed. The kinetics and kinematics of fertilizer particles and droplets were modeled by theoretical analysis of their motion characteristics in the air. The fertilization and variable spraying control system based on the core controller MCU (Microcontroller Unit) was set up. And the system can adjust the rotational speed of the disc and can automatically change the spraying volume by real-time detection of forward speed to achieve a constant spraying volume per unit area. The test results showed that: when the disc speed was greater than 90 r/min, the uniformity coefficient of variation was less than 15%, which satisfied the operational requirements; the uniformity coefficient of variation reached the minimum value of 10.03% when the disc rotation speed was 180 r/min, and the best fertilization performance was achieved at this time. In the spraying system, the actual spraying volume increased with the increased forward speed, and the relative error between the theoretical flow rate and the actual flow rate was 6.25% at most, and the average error was 5.94%, which could achieve the purpose of variable spraying. The research results can provide technical reference for the design and development of fertilization and spraying machinery in hilly areas.

Review of physicochemical properties and spray characteristics of biodiesel.

The United Nations Sustainable Development Goals by 2030 deal with seventeen goals for the planet's sustainability. The present review focuses on affordable and clean energy through the effective combustion of fuels with minimal pollution. Effective fuel spray characteristics are essential for combustion among various parameters and fuel properties. The inherent nature of the fuel has a functional relationship with the injection and injectors' conditions. Therefore, the study of fuels' physicochemical properties is essential. This review deals with the spray characteristics of biodiesel. Biodiesels in its purest form and blended with diesel, di-n-butyl ether, dimethyl ether, diethyl ether, ethanol, and butanol are considered for the study. The physicochemical properties of biodiesels, injection conditions, and injector constraints are analyzed to understand the spray process. The atomization features such as spray tip penetration, Sauter mean diameter, spray cone angle, spray area, and spray volume are analyzed. The chemical properties of biodiesel are utilized to describe the spray's transient behavior. In addition, supporting systems for spray diagnostics and models are also discussed. The highlighted significant spray challenges features and future research direction benefit the fuel and combustion community.

Ultrasonic sensor-based automatic control volume sprayer for pesticides and growth regulators application in vineyards

A study was conducted to design a sensor-based control volume sprayer for vineyard cultivation. The study aimed to develop cluster-specific pesticide and growth regulator application systems with improved penetration and minimum off-target losses, thus saving chemicals and overall cost. For the determination of design values of the control volume unit, physical properties (cluster length, width, and level of compactness) of grape clusters from seventeen major genotypes selected from vineyard research farm ICAR-IARI New Delhi were studied. For the design of the grape cluster detection unit, two different types of sensors, i.e., ultrasonic sensor (HC SR-04) and infrared proximity sensor (B0115NCT4U), were evaluated for their ability to detect the target (grape cluster) and the response time. The design of the spraying unit for the control volume sprayer also involved selecting suitable nozzles and operational parameters. The developed sprayer was evaluated for application of plant growth hormone (Gibberellic acid), and the performance was assessed in terms of droplet size, chemical application per cluster, cluster and berry growth characteristics, sprayer application rate, uniformity coefficient, and application time. The data on the physical properties of grape clusters revealed a maximum cluster length and width of 24.00 ± 0.91 cm and 18.80 ± 0.15 cm, respectively. The ultrasonic sensor had a comparatively higher sensing range, beam angle, and lower price than the infrared sensor. The spray uniformity for the hollow cone and flat fan nozzle varied significantly for the operating pressure range of 2–4.5 kg.cm−2. The developed sprayer consisted of a 3D printed control volume unit, ultrasonic sensor, two flat fan nozzles, microcontroller (Atmega 328P), relay switch, voltage converter, spray tank of 16-liter capacity, and 12 VDC battery. In case of developed sensor-based control volume sprayer, 30% and 35.48% saving in chemical use and application time, respectively, were observed compared to the conventional dipping method. The PGR application method has significant interaction with cluster length and berry growth as the main effect; however, failed to show a significant interaction with cluster width. Maximum cluster growth (16.89 ± 1.72 mm) was observed in PGR application with a developed sprayer.

Influence of the downwash airflow in Hexacopter Drone on the spray distribution pattern of boom sprayer

The spray characteristics of drone sprayers are significantly influenced by the downwash airflow produced by Drone multi-rotors. The present study aimed to study the influence of downwash airflow and the operational parameters of Drone sprayer, viz., flight height, travel speed, rotor configuration, payload and wind velocity on the spray distribution pattern for boom sprayer attachment to Drone. The boom type sprayer consisted of four numbers of flat fan nozzles placed at three different spacing viz., 30, 45 and 60 cm between each nozzle. The spray distribution pattern of the Hexacopter Drone was studied at three different operating pressures, viz., 3.0, 4.0 and 5.0 kg cm-2. A spray patternator of 5 m x 5 m was developed per the Bureau of Indian Standards (BIS) standard to study the spray uniformity of volume distribution pattern. The best spray uniformity was found as 0.37 % CV value at 60 cm nozzle spacing and 4 kg cm-2 operating pressure. The optimised parameters viz., 60 cm of nozzle spacing and 4 kg cm-2 operating pressure, the influence of downwash airflow on the spray volume distribution of hexacopter Drone with boom spray attachment were studied. The Drone hovered at three different heights, viz., 1.0, 2.0 and 3.0 m from the top of the patternator and spray operating pressure was maintained at 4 kg cm-2. It was observed that less volume of spray was collected at the middle portion when the Unmanned Aerial Vehicle (UAV) was hovered at 1.0 m height due to the direct impact of downwash airflow of rotors. The uniform spray volume distribution pattern was observed when Drone hovered from 1.0 m to 3.0 m height. A round vertex pattern of spray pattern was generated with boom type nozzles configuration due to the direct impact of downwash airflow of rotors. This study will be helpful in the configuration of nozzles attached to the drone sprayers, optimization of spray operational parameters, and revealing spray volume distribution pattern.

Spray coverage profiles from pecan air-blast sprayers, with a radial air-flow and a volute-generated focused air-flow, as affected by forward speed and application volume

Pecan (Carya illinoinensis) is an important specialty crop in the U.S.A., but yield is limited by several diseases and pests. In mature-tree pecan orchards, large air-blast sprayers are commonly used to apply the pesticides to control these diseases and pests. The spray coverage, deposition and profiles are poorly defined under the range of application scenarios, limiting the recommendations that can be provided to growers to maximize control while minimizing input costs. To explore effects of sprayer setting parameters such as travel speed and spray volume rate on spray coverage on tall targets we set up a system (a simple vertical patternator) using a 19-m-tall pole with cards attached at eight height levels from 5 to 19 m above ground, allowing to determine the vertical distribution pattern of two air-blast sprayers with different air discharge systems. Spray was applied with a standard radial-flow air-blast sprayer during six treatments being combinations of two travel speeds: 2.4 and 3.2 km/h, and three spray volume rates: 470, 940 and 1970 L/ha, as well as with a focused air-flow system (a volute) sprayer during four treatments being combinations of two travel speeds: 2.4 and 3.2 km/h, and two spray volume rates: 470 and 940 L/ha. Results show that using a standard radial air-flow sprayer, application volume affected coverage at heights ≤17 m (higher volumes resulting in more coverage). Higher speed using a standard radial air-flow sprayer resulted in greater spray coverage, but was inconsistent with the focused air-flow system. Using a focused air-flow system more spray coverage occurred at >17 m compared to a standard radial air-flow sprayer. Spray coverage profiles affirmed the rapid decline in coverage with height using a standard radial air-flow sprayer. The results may help guide decisions on volute use, spray volume, and spray partitioning to different parts of the canopy to improve spray profile characteristics for applying more uniform spray coverage to mature pecan tree canopies.

Assessment of map based variable rate strategies for copper reduction in hedge vineyards

Reduction of Plant Protection Products (PPP) has become a priority in agriculture, led by European directives and regulations due to the negative impacts and social awareness that pesticides have raised in the population. In viticulture, the use of copper to control Downy Mildew (Plasmopara viticola) is posing severe problems of soil, water and environment contamination, and European Commission is regulating its use through the EU regulation 2018/1981. A targeted spraying management can be done benefiting from the novel development of variable rate application (VRA) technology for orchard sprayers, resulting in savings of PPP. In this research, the quality of the application in terms of copper deposit in leaves of two VRA strategies where compared versus the conventional strategy performed by the farmer (REF). In each of the two VRA strategies, copper dosage was selected 1) maintaining copper dose per hectare (VRA) and 2) following the copper concentration listed in the product label (VRA[Cu]). Drone based NDVI maps from three commercial vineyards were used to characterize the structure of the vegetation in every vigour zone and manual measures in field were used to determine the most appropriate spraying volume rate according to canopy characteristics.Results show that a reduction of 33 and 44 % of copper used per hectare did not have significant impact on the quality of the application. On the contrary, while leaf deposit was comparable to that achieved by REF strategy, the product was better distributed across the entire canopy. Savings of 40 % of copper could be achieved in in the PPP application calendar along the season 2019 with no influence in disease control. Impact of PPP can be reduced by incorporating digital technologies, and the objectives of the Farm to Fork strategy and the European Green Deal can be met ensuring a more sustainable agri-food production.

The efficacy of sulfosulfuron on spontaneous barley as affected by the type, size, and outlet design of flat fan nozzle

Sulfosulfuron, when applied at a label-increased rate, can control spontaneous barley (Hordeum spontaneum K. Koch) in wheat. For optimization, a dose-response bioassay was conducted on three-leaf spontaneous barley plants treated with six sulfosulfuron doses (0, 6.75, 13.5, 27, 40, and 80 g a.i. ha−1) under the wind speed of 0 and 6 m s−1. Each of the doses was sprayed with three nozzle types (standard, anti-drift, and air induction), each with three outlet designs (single, dual, and triplet flat fan) at three nozzle sizes (02, 03, and 04, delivering 210, 315, and 420 L ha−1, respectively). Moreover, at 0 m s−1 wind, vertically and horizontally oriented water-sensitive papers (WSP) were treated with a dose of 40 g a.i. ha−1 sulfosulfuron. The horizontally-oriented WSP wetted less as the droplet size produced by the nozzles increased. The vertically-oriented WSP wetted more as the outlet number of nozzles increased. When the ED90 values averaged over the nozzle type at 0 m s−1 wind, the standard nozzle type had the best performance, followed by the anti-drift nozzle type and then the air induction nozzle type, while this ranking reversed at 6 m s−1 wind. Moreover, the optimized rates were achieved by increasing the spray volume and the outlet number of all nozzle types at both wind speeds. At 0 m s−1 wind, the standard triplet flat fan nozzle delivering 420 L ha−1 was the best with a low endo-drift. At 6 m s−1 wind, the air induction triplet flat fan nozzle delivering 420 L ha−1 was the best nozzle having a low exo-drift.

Using Inpyrfluxam to Control Peanut (Arachis hypogaea L.) Foliar and Soil-Borne Diseases

Aims: To determine peanut disease control and yield response to inpyrfluxam applied at various timings during the growing season.
 Study Design: Randomized complete block design with 4 reps.
 Place and Duration of Study: Field studies were conducted from 2016 through 2020 in the south Texas peanut growing region near Yoakum (29.276o N, 97.123o W).
 Methodology: Fungicides were applied with a CO2-propellant sprayer. The spray boom was equipped with three D2-23 hollow-cone spray nozzles per row with the middle nozzle centered over each plant in the row and another nozzle located as such to spray on each side of the plant to provide thorough coverage with a spray volume was 187 L ha-1. Some studies included a non-treated control while other studies included chlorothalonil only at 1.26 kg ha-1 as the comparison treatment. Each plot consisted of four rows spaced 97 cm apart and 7.9 m long.
 Results: Inpyrfluxam applied twice in a 4 to 5 fungicide spray program in combination with chlorothalonil provided early leaf spot control as good as or better than the standards of chlorothalonil plus either azoxystrobin alone or azoxystrobin plus benzovindiflupyr applied 2 times. Control of Rhizoctonia pod rot, caused by Rhizoctonia solani Kuhn, with inpyrfluxam at 0.04, 0.05. 0.075, or 0.1 kg ai ha-1 applied 2 times during the growing season was comparable to two applications of azoxystrobin at 0.22 kg ai ha-1. Control of southern blight, caused by Sclerotium rolfsii Sacc., with one to two applications of inpyrfluxam at 0.05 to 0.1 kg ha-1 was comparable to azoxystrobin plus benzovindiflupyr. Peanut yield response was influenced by the level of soilborne and foliar disease control exhibited with each fungicide program, as those programs which provided the best control also produced the highest yield.
 Conclusion: These studies show the ability of inpyrfluxam to provide control of multiple diseases found in southwest peanut production.

Double-spraying with different routes significantly improved control efficacies of herbicides applied by unmanned aerial spraying system: A case study with rice herbicides

An unmanned aerial spraying system (UASS) is one of the most important systems for herbicide applications. To date, no study has compared the control efficacies of herbicides applied by UASSs with different application strategies against weeds. We applied post-emergence (POST) herbicides using a six-rotor UASS on rice (Oryza sativa) fields with different spraying volumes (22.5, 30, 45, and 60 L ha−1) and different spraying route strategies (one-time spraying or two flight sorties routed in length and breadth). The spraying volume significantly affected (P < 0.05) control efficacies against Echinochloa spp., Leptochloa chinensis, Ammannia baccifera, Monochoria vaginalis, Cyperus difformis, and overall weeds. The spraying route strategy significantly affected control efficacies against Echinochloa spp., Leptochloa chinensis, Ammannia baccifera, and overall weeds. Treatment with the double-spraying strategy significantly increased the control efficacies against Echinochloa spp. and Leptochloa chinensis compared with one-time spraying. For weeds susceptible to herbicides applied, treatments with a spraying volume of 30 L ha−1 showed control efficacies >90%; for grassy weeds, UASS applications with double-spraying routed in length and breadth with a spraying volume of 60 L ha−1 did not show a significant difference with the manual spraying with a spraying volume of 450 L ha−1 in control efficacies. This study revealed different optimal spraying volumes for controlling different groups of rice weeds and demonstrated a new spraying strategy for UASS applications that can be used to improve herbicide application practices with UASSs.

The effect of spray on the radiation transfer of concentrated solar irradiation in a novel designed solar steam generator

High-temperature steam is required to produce hydrogen with Solid Oxide Electrolysis Cells (SOEC), but generating steam can be power-consuming. Concentrated solar power is a good candidate for replacing electricity or fossil fuel in generating steam. This paper investigated the effect of spray on radiation transfer in a novel solar steam generator designed to utilize spray cooling to enhance heat transfer. The Monte Carlo ray-tracing technique, considering the absorption of droplets, absorption of water vapor, and multiple scattering of droplets, is employed to analyze the flux density at the focal plane and the spatial scattering power distribution of droplets. The results show that the total incident power transmittance is found to be in positive proportion to the mean droplet diameter while in reverse proportion to the spray volume fraction. Since the maximum difference in spectral transmittances is less than 1%, it is not feasible to adjust the wavelength for higher transmittance. The nozzle position seems highly affects the solar power distribution, and the central area is more affected than the outer area. Thus, increasing the spray volume fraction may uniform the flux density but reduce the transmittance. The spatial scattering power analysis indicates that increasing the droplet diameter can effectively improve the transmittance when the spray volume fraction keeps constant, which may be a solution when applied to a large-scale steam generator.

Numerical Simulation of the Trajectory of UAVs Electrostatic Droplets Based on VOF-UDF Electro-Hydraulic Coupling and High-Speed Camera Technology

The electrostatic spray technology can significantly improve the utilization rate of liquid medicine under the operation characteristics of unmanned aerial vehicles (UAVs) with small load and low spray volume. To explore the settlement law of electrostatic droplets, further improve the amount of droplets deposited in target crops, and reduce the loss of missing target, this study adopted the method of combining numerical simulation and high-speed photography to study the movement characteristics of electrostatic droplets of UAV induction conical electrostatic nozzle. Based on the droplet spatial dynamics theory, a user-defined function and volume of fluid (UDF-VOF) multiphase spray model is established to simulate the trajectory of electrostatic droplet. TEMA software is used to analyze the droplet motion image under electrostatic field, and the characteristic parameters, such as trajectory and velocity are obtained. Theoretical analysis and spray test results show that the main factors affecting electrostatic droplet settlement are charging voltage, droplet falling distance, and airflow velocity. The optimal charging voltage of electrostatic droplet is 14 kv, the maximum charge-mass ratio is 1.04 mC/kg, and the average particle size is 209.77 μm. The numerical simulation results show that spray height, charging voltage, and lateral wind speed have significant effects on droplet sedimentation. The results of high-speed camera analysis show that the induced electric field causes the droplet to adsorb the target crop, resulting in the droplet movement trajectory deflection.

Intensification Effect of a Multi-Jet Structure on a Multiphase Flow and Desulfurization Process in a Fluidized Bed.

The introduction of a multi-jet structure at the bottom and middle of a fluidized bed can intensify the interphase mixing and improve desulfurization efficiency. The computational fluid dynamics were used to study the gas-liquid-solid flow in a bottom multi-jet fluidized bed and middle multi-jet fluidized bed (BMJFB and MMJFB). It was found that for the gas-liquid-solid interphase mixing, the intensification effect of introducing the multi-jet structure in the middle of the bed is more obvious than that in the bottom. The effect of the water spray volume flow rate on the MMJFB was examined under the same conditions. The results showed that with the increase of the water flow rate, the gas-liquid-solid interphase mixing and desulfurization process are promoted in the MMJFB, and its desulfurization efficiency reaches 68.2%. The effects of the width and number of multi-jet structures on the MMJFB were also investigated. The results show that when the jet width is 20 mm and the number of jets is four, the gas-liquid-solid three-phase is uniformly mixed and the desulfurization efficiency of the MMJFB equals 69.3%, which is 18.5% higher than that of the conventional fluidized bed.

Reflections on Resistance to Pesticides in Relation to Application Techniques

A wide range of pesticides have been developed, but these have mostly been formulated to mix with water as the diluents and are applied as a spray, either with ground equipment or from aircraft using hydraulic nozzles. The effectiveness of any technique is a function of the interaction of various factors, including plant size, volume of spray applied, spectrum of droplets sprayed, distribution of droplets relative to location of pests on plants, timing of an application relative to crop monitoring and subsequent persistence of the deposits of pesticide, especially after rain.

DEVELOPMENT AND FABRICATION OF AGRICULTURAL PEST CONTROL SYSTEM

Research is “creative and systematic work undertaken to increase the stock of knowledge”. It involves the collection, organization and analysis of information to increase understanding of a topic or issue. Efficient use of pesticides can helpful to control plant pests and diseases to increasethe crop yields. The use of agrochemicals can effectively enhance the quantity and quality of crop;however, it increases the environmental risks in recent years. Pesticide application utilizes the to a significant percentage of the production cost. During chemical plant protectionpractices, over application of pesticide or inefficient spraying equipment may cause serious issueson human healthand the environment. Effective pesticide application is a critical activity during crop production season that requires efficient spraying machinery with proper calibration as well as relevant regulations to reduce off-target spray deposition. Thus, the significant among all the factors which are influencing the degree of off-target spray deposition is the design and application spraying technology Conventional agricultural pesticide application practices havedeveloped a contradiction among the yield enhancement, cost effectiveness and environmental protection. Therefore, pesticides have to be applied using suitable spraying systems to avoid adverse effects on environment as well as human health. Thus, in recent decades, spraying methods and technologieshave been undergoing continuous evolution. Conventional sprayerswere very laborious and International Journal of Scientific Research in Engineering and Management (IJSREM) Volume: 07 Issue: 01 | January - 2023 Impact Factor: 7.185 ISSN: 2582-3930 © 2023, IJSREM | www.ijsrem.com DOI: 10.55041/IJSREM17568 | Page 2 requirevery heavy machinery to operating them in the field. They increasethe application amount because of no proper application method for spraying nozzles, crop foliage detection, and weather parameters. advancement in spray application technologies increase crop production and increase pesticide efficiency on weed and insects in the field. Spray loss in the form ofspray drift, weather effects, target detection, and control flow nozzles problem solved by advancedpesticide applicationtechnologies. The time-consuming problem for tank refilling is reduced withultra-low volume sprayers and fine droplet spray nozzles. With time the crop maintaining technology-advance fromweeds and pest, detection to spray application nozzles. The objective of this chapter is to highlight the attachments conceived by both electronics and mechanical components which implies for the working of agricultural spraying machine.

Evaluation of the Wind Field and Deposition Effect of a Novel Air-Assisted Strawberry Sprayer

Strawberry is a widely cultivated cash crop in China. In order to control pests and diseases on strawberries, there must be sufficient deposits on the abaxial surfaces of the leaves. Air-assisted technology can effectively increase the deposition on the abaxial surfaces of the leaves; however, most air-assisted equipment is not suitable for application due to the pattern of strawberry planting. Therefore, a novel air-assisted strawberry sprayer was developed, the static and dynamic wind fields were measured using a 3D anemometer, and the effectiveness of the application at different spray angles and wind speeds was evaluated. In addition, a comparison of the deposition effect in the strawberry canopy between the air-assisted strawberry sprayer, knapsack sprayer, and spray gun was conducted. The results showed that in the static wind field test, a difference between the center and edge wind fields was obtained, which was correlated with the distance and the outlet wind speed. In the dynamic wind field test, the wind field was found to be rolling backward during the movement, and an inward vortex was obtained. In the field, the data showed that a spray angle of 30° and a wind speed of 16 m·s−1 had the best deposition on the abaxial surface, with a coverage of 36.5% and 38.3% in the upper canopy and 6.2% and 7.9% in the lower canopy, respectively. Moreover, the air-assisted strawberry sprayer was found to have a higher deposition efficiency on abaxial surfaces than the knapsack sprayer and spray gun at a lower spray volume, the values of which in the upper and lower canopies were 42.8% and 29.7%, respectively. In conclusion, the air-assisted strawberry sprayer has the potential for the crop protection of greenhouse strawberries, and more evaluations are needed to improve the sprayer in the future.

Estimating sea spray volume flux with a laser gauge in a self-consistent system

Sea spray is one of the drivers of heat, mass, and gas exchange between the ocean and the atmosphere, and its volume flux could be estimated by the record of the laser intensity. In the laboratory experiments, the relationship between sea spray and laser intensity could be established since the returned laser intensity of the observing gauge and spray concentration can be observed instantaneously. However, the difficulty to generalize the laboratory result to field observations is that the measurement of sea spray is usually unavailable on the open seas. Recent studies introduced an environment variable (atmospheric extinction coefficient for instance) to relate the laser intensity to spray volume flux for both laboratory and field observations so that the relationship established in the laboratory experiments could be extended to open seas. These studies however gave estimations of great difference since the relationships between each pair of the variables (spray volume flux, laser intensity, and the atmospheric extinction coefficient) are considered separately. This work established a self-consistent system composed of the three variables, in which the relationship between each pair of the variables in the system is consistent with that deduced from their respective relationships with the third variable. Consistency here we means that if Y=f(X), Y=g(Z) and Z=h(X), then Y=g(h(X))=f(X) is expected. The consistency of the relationships ensures that the estimation of the sea spray volume flux from laser intensity is robust. We established self-consistent relationships for the variables in the system composed of laser intensity, environment variable, and sea spray volume flux, for both laboratory and field experiments. Among them, the relationship between wind speed and spray volume flux is a reasonable reflection of the physical properties in two ways: a threshold value of spray volume flux at low wind speeds and the saturation at strong wind speeds. For a uniform regression of wind speed onto spray volume, a dimensionless parameter concerning wind speed is needed.

Development and validation of a new reduced diesel/natural gas mechanism under engine-relevant conditions

A simplified mechanism of diesel/natural gas blend was developed for a dual fuel engine built from a previously reported detailed mechanism of a n-dodecane and natural gas. In the model, n-dodecane was selected as the representative substance of diesel and the mixture of methane, ethane and propane was selected as the representative substance of natural gas. The simplified mechanism was obtained by using the direct relation graph, the directed relation graph with error propagation, and the sensitivity analysis simplification method. On this basis, a simplified n-dodecane-natural gas mechanism with 141 species and 739 reactions was established. In addition, the experimental data and detailed mechanism are used to compare with the n-dodecane-natural gas dual fuel simplified mechanism established in this paper, and have been widely verified in 0-D and 1-D combustion systems for the first time, including ignition delay time, laminar flame velocity, premixed flame species, HCCI combustion, which verify the rationality of the new simplified mechanism. Then the mechanism is coupled to CFD software to simulate the spray combustion of constant volume spray under engine like conditions. The results show that the mechanism has high reliability and can be coupled with CFD.