Spray Mixing Research Articles

Operation parameters investigation on combustion and emission of a non-road diesel engine based on orthogonal experiment design at different altitudes

For improving the combustion and emission performance of engines operating at high altitude regions, a two OED optimization method was proposed. The influence of each factor on the target was analyzed and discussed through a primary OED. Based on the primary OED test, factors with less influence were excluded to reduce factors in the secondary OED test. The results showed that low intake pressure led to poor spray mixing, prolonged ignition delay, and incomplete combustion, resulting in deteriorated power output, fuel economy, and emission characteristics. After two OED optimizations, The NOx emissions increased significantly by 40.5 % and 122.5 % in the first and second optimization, respectively, however, the ISFC decreased by 13.4 % and 25.2 %, and CO decreased by 13.0 % and 25.2 % in the first and second optimization, respectively, as well as ultra-low carbon smoke emissions was achieved. The related theories and methods' advantage can be extended to engineering applications and has good practical value.

Effect of sulfur and potassium foliar applications on wheat grain protein quality

ContextThe effects of sulfur and potassium fertilizers on wheat yield and quality have been well studied, but most of them are used as basal fertilizers. However, the root system is senescent at the later stages of wheat growth and cannot absorb sufficient sulfur and potassium fertilizers plant needed. It is still unclear whether sulfur and potassium foliar applications at the later stages can affect wheat yield and quality. ObjectiveThis experiment was conducted to investigate the changes of sulfur and potassium accumulation and transport, protein synthesis and flour processing quality after foliar application of sulfur and potassium fertilizers, transport and the relating physiological mechanisms. MethodsIn 2020–2021 and 2021–2022, a three-factor split plot experiment was carried out in the middle and lower reaches of Yangtze River, with wheat variety, concentration of sulfur fertilizer and potassium fertilizer served as main factor, subfactor and sub-subfactor respectively. ResultsIn the study from 2020 to 2022, the albumin protein content of both varieties decreased in the nutrient spraying treatment, particularly in the high potassium level. However, there was no significant effect on the globulin content. Moreover, the gliadin protein content decreased in the sulfur spraying treatment alone, but significantly increased the wheat gluten content, and thereby the total protein content. We also found significant genotypic differences in the composition and content of high molecular weight wheat glutenin subunits (HMW-GS) between the two varieties. The foliar spraying of sulfur and potassium fertilizers significantly increased the content of subunits 1 and 8 in Yangmai (YM15) and subunits 7 and 12 in Yangmai (YM16), and the effect of mixed spraying was better than single-nutrient spraying, especially the amount of 0.2 % sulfur and 0.3 % potassium fertilizer treatment. ConclusionsThe superimposed effect of sulfur and potassium effectively increased the total protein content by promoting the accumulation of sulfur in transit to the seeds, increasing the substrate supply level, and enhancing enzyme activity. Although sulfur and potassium combination can improve the grain protein quality and flour processing quality, too high spraying concentrations can decrease the flour processing quality. ImplicationsSpraying the appropriate amount of 0.2 % sulfur and 0.3 % potassium fertilizer can serve as an optimization measure for high-quality and efficient production of different types of wheat varieties.

Modelling of wall-bounded cavitating flow and spray mixing in multi-component environments using the PC-SAFT equation of state

This work introduces a numerical multiphase model for multi-component mixtures, utilizing tabulated data for physical and transport properties across a spectrum of conditions from near-vacuum pressures to supercritical states. The property data are derived using Perturbed Chain Statistical Associating Fluid Theory (PC-SAFT), vapor-liquid equilibrium (VLE) calculations, entropy scaling methodologies, and Group Contribution (GC) methods. These techniques accurately reflect the thermodynamic behaviors of real fluids, avoiding the empirical estimation of Equation of State (EoS) input parameters. Implemented in OpenFOAM, the fluid dynamics solver is designed to address the three-dimensional Navier-Stokes equations for multi-component mixtures. The methodology integrates operator splitting to manage hyperbolic and parabolic steps distinctively. Hyperbolic terms are solved using the HLLC (Harten-Lax-van Leer-Contact) solver with temporal integration performed via a third-order Strong-Stability-Preserving Runge–Kutta (SSP-RK3) method. Viscous stress tensor contributions in the momentum equation are handled through an implicit velocity correction equation, while parabolic terms in the energy equation are explicitly solved. The simulation efficiency is further enhanced by adaptive Local Time Stepping and the Immersed Boundary (IB) method, which addresses interactions between the fluid and solid boundaries. Turbulence is resolved using the Wall Adaptive Large Eddy (WALE) model. Applied to high-pressure diesel fuel spray injections into non-reacting (nitrogen) gas environments, the model has been validated against Engine Combustion Network (ECN) data for the Spray-C configuration, featuring a fully cavitating multi-hole orifice. Results demonstrate that the model achieves accurate predictions across a broad range of tested conditions without the need for tuning or calibration parameters.

Numerical study on the inner spray and combustion of active pre-chamber jet ignition for achieving higher performance of a hybrid engine under ultra-lean conditions

The mechanism of active pre-chamber (APC) inner fuel-air mixing, initial flame kernel formation, and jet flame evolution is still not clear. In this study, different APC inner geometry structures coulped with different mixture status were designed to synthetically analyze the inner gas flow, spray mixing, and hot jet flame evolution. The results showed that the APCs with small cone angles of 45° and 50° could promote the fuel-air mixing and spray atomization in a wider APC top space compared to APCs with large cone angles of 60° and 65°. An appropriate APC cone angle of 55° could reduce rich mixture zone and facilitate rapid flame kernel formation, fast flame propagation, and high jet activity, which was good for igniting the in-cylinder ultra-lean mixture. APCs with real fuel injection showed one heat release rate (HRR) peak, while APCs filled with homogeneous mixture showed the typical two peaks in the HRR profiles, the suitable mixture in APC duct section burned and formed the second HRR peak. The short thick APC induced the rich mixture distributed around the spark plug to form the initial flame kernel and showed a faster concentrated combustion process along with a higher pressure difference between APC and MC.

Combustion modes of kerosene spray in a scramjet combustor with different injection schemes

Combustion modes of kerosene spray in a scramjet combustor condition with different injection schemes are experimentally investigated at Mach 2.52. The study is based on two single injectors with nozzle diameters of 0.79 and 1.14 mm and two dual injectors with nozzle diameters of 0.56 and 0.72 mm, respectively. The results show that the weak combustion mode has little effect on the flow field, while the intensive combustion mode has the opposite effect. The dual injector can promote evaporation and mixing of the kerosene spray. Compared with the dual injector, intensive combustion cannot occur when a single injector is used, and the flame stability range is also narrower. As the nozzle diameter of the injector increases, the distribution and oscillation of kerosene spray change significantly, transition from the weak to intensive combustion mode occurs at a higher equivalence ratio, and the flame stability range increases. However, change in the nozzle diameter does not affect the overall process of combustion mode transition. For the single injector, intensive combustion still cannot occur when the nozzle diameter changes. In addition, change in the nozzle diameter has little effect on combustion heat release when the combustion mode remains unchanged.

Optical study on spray mixing, flame propagation and jets evolution within visible methanol active pre-chamber for turbulent jet ignition

Methanol spray impingement, mixing, flame propagation and jet evolution within the narrow-confined active pre-chamber (APC) with complex walls were experimentally observed by optical method for the first time. The effects of injection pressure and duration was investigated on an actual-geometry optical APC assembled in constant volume combustion chamber (CVC). Exploration on APC internal processes within static environments forms the basis for optimization of APC and analysis of jet formation. Mie scattering coupled with flame natural luminosity imaging were used to record spray mixing and combustion. The results show that in the APC with narrow-confined space, methanol spray undergoes three wall impingements, inducing a tumble that promotes mixing. High injection pressure enhances rapid spray tip penetration, while long injection duration slows methanol diffusion. In longer injection duration cases, the spray tip after the third impingement interferes with subsequent sprays. For higher injection pressure, this interference occurs in the APC cone section due to a larger spray cone angle, whereas for lower pressure, it happens in the APC duct section. Higher injection pressure also causes more spray to impact the APC bottom after the first wall impingement, hindering flame acceleration in the duct section. Irregular flame propagation is observed in the APC cone section due to wider space and uneven mixture conditions, while the convergent geometry from the APC throat to the duct section significantly accelerates flame propagation. The APC jet appears due to the pressure difference between the APC and the main chamber, with the brightness and length of the visible flame jet increasing with APC flame luminosity and pressure difference. A Mach ring structure is observed initially, but the jet velocity decreases as the Mach ring disappears during the APC inner flame extinguishing process. Through this study, the actual spraying and combustion process in APC is experimentally captured and revealed, which are an important contribution for APC optimization and development.

Experiments and modeling of the thermal spray-chasing phenomenon during split injection processes

Spray chasing is a specific manifestation of the interaction between split injections, where the mass and heat transfer between the pilot and main sprays significantly influence fuel mixing and ignition processes. In this study, a spray-chasing model is developed and validated based on optical diagnostic results, aiming to theoretically support the development of injection strategies that are more environmentally adaptive and offer improved performance. A series of optical diagnoses of diesel split injection is performed in a constant volume combustion chamber using diffused back-illumination imaging and high-speed schlieren imaging. The extent of the spray-chasing phenomenon is modulated by regulating the injection dwell time (DT) and ambient temperature. For inert sprays, when the background temperature exceeds 790 K, the liquid spray-chasing phenomenon can be disregarded owing to the premature evaporation of the pilot spray. Although shortening the DT can promote the development and mixing of the main spray, the lack of evaporation in the pilot fuel pocket leads to a higher local fuel concentration in the interaction zone after spray chasing, which will hinder the subsequent ignition of the main spray. For reactive sprays, the variations in spray chasing patterns under different operating parameters are determined and their impact on the ignition process is evaluated by combining optical test results with theoretical models. Under cold start conditions, the ignition delay and ignition location of the main spray exhibit a non-monotonic trend with increasing injection dwell time. Optical diagnosis observes that compared to DT of 200 us and 1500 μs, the main spray exhibits both valley in ignition delay time and ignition location at DT = 900 μs. The spray-chasing model identifies approximately 1020 μs as the optimal theoretical DT, expected to best facilitate ignition of the main spray. However, under hot-start conditions, even though the spray-chasing mode varies with different injection dwell times, the ignition characteristics remain essentially unchanged due to the limited promotion effect of split injection on ignition.

Experimental Tensile Strength Analysis of Different Manufacturer Oring

Importance and Purpose of Tensile Testing on ORings The tensile test on rings and especially on O-rings is primarily carried out for quality assurance reasons. The tensile test provides information about the formulation quality (evaluation of the absolute values, strength of the material, and determination of formulation changes). For example, it is not possible to detect an exchange of the polymer of compounds with different molecular weights and/or a different molecular weight distribution (e.g. highviscosity press mix by low-viscosity spray mix) by infrared spectroscopy (IR), but only by tensile testing and possibly by long-term compression set tests. Furthermore, the tensile test provides information on subsequent changes compared to the prototype condition. The Influence of Processing In the case of some O-rings, due to poor processing, it is not the strength value of the material that is determined, but the lower strength of the joining line (= confluence point of the rubber compound in the production of the O-ring in the injection mold) at which the O-ring tears. This problem depends on the material (e.g. certain acrylate rubbers), the tool and the process parameters. The joining line can usually be detected in advance by a visual and strain test or by relatively large scatter in a tensile test. Typical for the scatter in tensile tests of O-rings are 5-10%-points standard deviation related to the mean value of the elongation at break or the tensile strength. An important characteristic of good processing is the achievement of the optimum degree of vulcanization. However, there is no generally valid optimum, but this must be determined depending on the intended application of the elastomeric component. If, for example, the tear resistance is the most important material parameter for the finished product, a different degree of crosslinking or a different cross linking density must be aimed for than if, for example, a low

An optical study on the cross-spray characteristics and combustion flames of automobile engine fueled with diesel/methanol under various injection timings

The fundamental research on the spray and combustion characteristics of diesel/methanol dual injection was explored in this study. A constant-volume combustion chamber was modified to accommodate cross-fuel injection by adding another fuel supply and an injection system. The effects of diesel/methanol injection timings on cross-spray and flame development were analysed for various injection intervals and pressures. The results showed that as the injection pressure increased, the high atomisation of the diesel–methanol mixed spray plume promoted its combustion. After diesel–methanol impingement at injection pressure of 100 MPa, a significant increase in the spray area occurred up to 62.5 % compared to its value at 60 MPa, resulting in a shortened combustion ignition delay, increased flame lift-off length and reduced soot generation. In addition, when methanol was used prior to diesel injection, the combustion ignition delay and flame lift-off length increased and soot generation decreased, as the diesel injection timings delay increased. Soot generation can be reduced by up to 33.3 % compared to that generated via the simultaneous injection of diesel/methanol at 60 MPa, by utilising a high injection pressure and proper injection timing. The study findings will provide a theoretical basis for the development of diesel/methanol dual-fuel direct-injection engines.

Optimizing the Zn, Mn, and Fe mineral dose as tank mix foliar application for improvement of fruit yield, quality, and uptake of nutrients in the kinnow mandarin

Kinnow production is hampered due to the lack of micronutrient applications such as zinc (Zn), iron (Fe), and manganese (Mn), which play a significant role in the metabolic activities of the plant, affecting yield and quality. The farmers of the region use mineral micronutrient fertilizers, but it leads to phytotoxicity due to unoptimized fertilizer application dose. In the present investigation, an attempt has been made to optimize the Zn, Mn, and Fe minerals dose as tank mix foliar application for improvement of fruit yield, quality, and uptake of nutrients. The twelve combinations of different doses of zinc sulphate, manganese sulphate, and ferrous sulphate fertilizers replicated three times were tested at kinnow orchards established at Krishi Vigyan Kendra, Bathinda, Punjab, India. The data revealed that the fruit drop was significantly low in the treatment F12 (43.4%) (tank mix spray of 0.3% ZnSO4 + 0.2% MnSO4 + 0.1% FeSO4 ) compared to control treatment. The fruit yield per tree was significantly higher in the treatment F12 compared to untreated control. The juice percentage was also recorded higher in treatment F12 as compared to control, and the juice percentage improved by 2.6%. The leaf nutrient analysis also revealed translocation of higher amount of nutrient from leaf to fruit under optimized supply of micronutrient. Thus, the application of tank mix spray of 0.3% ZnSO4 + 0.2% MnSO4 + 0.1% FeSO4 may be used for better fruit yield and quality.

Investigations of spray breakup Rayleigh–Taylor instability via multiphase lattice Boltzmann flux solver

Poor fuel–air mixing of the diesel spray in low ambient temperature and pressure or thin air leads to intricate fuel breakup mechanism near the nozzle, which still remains worth of study. In this study, a pressure-based modified multiphase lattice Boltzmann flux solver (MLBFS) is proposed to accommodate the fuel spray breakup characteristics of multiphase, multicomponent, and large density ratio, in which the source terms of governing equation are modified emphatically for high injection pressure. Therefore, the characteristics of microscopic diesel spray breakup induced by Rayleigh–Taylor instability are investigated, including spray penetration, spray area, and spray arc length. It is revealed that the spray penetration is increased exponentially with the fuel–air density ratio Rρ. Influenced by air resistance and circulation interference, the roll-up vortex, droplet size, and spray area increase with the decreasing of Rρ (corresponding to high ambient pressure). Affected by entrainment and Rayleigh–Taylor instability, the development of the spray arc length experienced three stages: rapid growth, peak, and violent fluctuation, in which the lower Rρ facilitates development. It is concluded that Rayleigh–Taylor instability is favorable for stimulating the spray internal circulation of spray to enhance entrainment with surrounding air, while improving roll-up and breakup in the spray tail region. Such investigation is conductive to better understanding the micro-breakup mechanisms of fuel spray in the spray-induced internal combustion engine.

Combustion modes of kerosene spray in a supersonic combustor

The mixing and combustion characteristics of liquid kerosene spray in a cavity-based supersonic combustor under a Mach 2.52 inflow are experimentally and numerically investigated. The combustion mode transition of kerosene spray includes two aspects: 1. As the injection pressure increases, the combustion mode shows a transition of weak-intensive-transitional(weak to intensive)-weak-blowoff; 2. in the transitional combustion mode, there is a transition from weak to intensive combustion over time. In the weak combustion mode, the combustion chamber pressure increases slightly, and the flame is inside the cavity. In the intensive combustion mode, the pressure rises sharply from the isolation section and the flame is a typical cavity stabilized combustion mode. The weak combustion at low/high injection pressure is due to rich/lean fuel inside the cavity. In the transitional combustion mode, the flame on the downstream wall of the cavity gradually expands and joins with the flame inside the cavity, evolving from weak combustion to intensive combustion. The transition is accomplished in a very short time, on the order of milliseconds. This study deepens the understanding of the combustion mode of scramjet engines and provides a reference for the design of fuel injection schemes for scramjet engines.

Numerical Investigations of Pseudo-Boiling and Multi-Component Mixing Under Trans-/supercritical Conditions for Engine Applications

ABSTRACT The fuel injection and mixing process are often carried out under trans-/supercritical conditions for engine applications; however, the process is still unclear. In this study, based on OpenFOAM, a multi-component trans-/supercritical spray model based on the KT/KNP scheme is developed, which covers the special real fluid equation of state, various mixing rules and modified thermodynamic properties. In addition, the PIMPLE algorithm is extended to deal with the high nonlinearity. First, a one-dimensional advection case is applied to evaluate the performance of the model. Then, the effect of various mixing rules and pseudo-boiling phenomenon on n-heptane/nitrogen jet are thoroughly analyzed under trans-/supercritical conditions. The results show that the jet is extremely sensitive to the changes of the initial jet temperature and chamber pressure, and the “heat shield” effect of pseudo-boiling delays the breakup and mixing in the transcritical jet. With the mixing of different components, unlike the single-component condition, the pseudo-boiling intensity will increase. The increase of pressure and occurrence of mixing will lead to the decrease of pseudo-boiling temperature, and the pseudo-boiling will end earlier, which is obviously different from the single-component fluid case. For the n-heptane/nitrogen mixture, when the mole fraction of n-heptane in the mixture changes from 1.0 to 0.7, and the pseudo-boiling temperature decreases from 571 K to 465 K. With increasing injection temperature or chamber pressure, the pseudo-boiling intensity gradually decreases, and the potential core shortens, the difference among various mixing rules decreases. When the injection temperature is higher than 571 K, the pseudo-boiling phenomenon no longer exists. When the chamber pressure reaches 9 MPa, the pseudo-boiling strength is very low. Therefore, the spray mixing under supercritical conditions will be more sufficient. With the occurrence of mixing, the critical parameter gradually transitions from the critical value of n-heptane to the critical value of nitrogen, which strongly depends on the mixing rule.

Numerical Investigation on the Combustion and Emission Characteristics of Diesel Engine with Flexible Fuel Injection

As the main engineering power plant, diesel engines are irreplaceable in the future. However, the stringent emission regulations impose many tough requirements to their developments. Recently, flexible fuel injection strategy has been recognized as an effective technology in creating an advanced spray and mixture formation and improving combustion efficiency indirectly. However, the detailed combustion and emission behaviors under flexible fuel injection are still unknown. Therefore, this paper aims to investigate the combustion and emission characteristics under flexible fuel injection and explore an optimal injection strategy for high-efficiency combustion. A numerical simulation method is conducted by coupling the large-eddy simulation (LES) model and the SAGE combustion model. Then, the spray mixing, combustion flame propagation and emissions formation under various multiple-injection strategies are investigated. Results reveal that initial an ultrahigh injection pressure has a significant influence on the spray’s axial penetration while dwell time mainly affects the spray’s radial expansion. Under an initial ultrahigh injection pressure, the turbulence kinetic energy (TKE) becomes larger, and the vortex motions are stronger, contributing to a better spray turbulent mixing. Meanwhile, a snatchier flame structure with a favorable level of equivalence ratio and a homogeneous temperature distribution is obtained. In this way, the peak heat release rate (HRR) could increase by 46.7% with a 16.7% reduction in soot formation and a 31.4% reduction in NOx formation.

Investigating the effects of split injection with different injection patterns on diesel spray mixing

In recent studies, it has been established that improvements in the injection rate results in improved mixing, combustion efficiency, and reduced pollutant emissions. Varying injection rates have been observed to find out the optimization injection rate. In this study, split injection with different injection rates was used as the flexible injection to investigate the diesel spray mixing efficiency. Large eddy simulation (LES) was used to investigate the complex diesel mixing processes of unsteady turbulence. The split injection was combined with different fuel injection rates to approximate the ramping-down rate shape. The simulation results of flexible injection rates showed the formation of a highly unstable aerosol vapor structure with the turbulence structure that produces the vortex in the spray area. The powerful injection rates provide a very strong spray turbulence structure and vortex formation. The backflow and vortex are evident when the dwell time of injection is setup. The flexible injection rates have a huge influence on the mixing efficiency of the fuel spray. Basic mixing efficiency predictions revealed that the dwell time of the split injection and inverse injection pressure affect the turbulence structure. Another prediction is that the initial pressure of the injection rate has a significant impact on evaporation and mixing efficiency, even using the same fuel quantity and same condition. The double-rectangular split injection has a slight effect on the spray radial extension, and the spray area grows rapidly while the equivalence ratio is low. The double-drop split injection with a high pressure difference has a great influence on the spray radial extension and spray length. Additionally, the higher injection pressure results in lower equivalence ratios and more efficient mixing.

INVESTIGATION ON IMPACTS OF ELLIPTICAL DUCTS ON MACROSCOPIC SPRAY CHARACTERISTICS OF DUCTED FUEL INJECTION

To study the influence of ducts other than circular shapes on spray characteristics of ducted fuel injection (DFI), experimental and simulation methods were used to study the impacts of elliptical ducts on DFI macroscopic spray characteristics. Two elliptical ducts, small and large, were used, with a circular duct for comparison. The small elliptical duct had the same hole cross-sectional area as the circular duct, and the large elliptical duct had a larger cross-sectional area. The DFI spray configuration with the elliptical duct promoted the axial dispersion and weakened the radial dispersion of spray with respect to free spray. Different spray-duct interactions caused differences in spray characteristics, manifested in changes in velocity field and pressure field. The spray velocity field of the circular duct had the best effect on promoting spray dispersion, followed by the small elliptical duct, and finally by the large elliptical duct compared to that of free spray. Furthermore, the pumping effect caused by the pressure differences between inside and outside the duct promoted the thorough mixing of spray and ambient gas inside the duct. From the radial velocity of ambient gas flowing to spray around the duct inlet, the pumping effect of the circular duct was the strongest, followed by the small elliptical duct and finally by the large elliptical duct.

Experimental Investigation on Spray Mixing and Droplets Evolutions in Co-Flow Around the Bluff Body

Experimental Investigation on Spray Mixing and Droplets Evolutions in Co-Flow Around the Bluff Body

Experimental and numerical investigation on fuel/air mixing and macroscopic spray characteristics of free spray, convergent-divergent, and straight duct sprays under non-vaporizing conditions

In this study, the convergent-divergent (CD) and straight (ST) duct sprays were conducted for comparison with free spray to investigate the diesel macroscopic spray characteristics and mixing process. The schlieren visualization system with a high-speed camera was performed with a 0.22 mm single-hole heavy-duty diesel injector. The injection pressure varied from 120 via 140 to 160 MPa, with the ambient pressure being set at 40 bar. The experimental result showed that CD and ST duct spray had much higher spray tip velocity compared to free spray during the early spray stage. CD duct spray presented a more dispersed and more distributed spray morphology along with larger-scale flow vortexes and gas entrainments, indicating the promoted fuel-air mixing process. Large-eddy simulations (LES) were conducted to analyze the pumping effect, the local separation of the boundary layer, and the air entrainment of different sprays. Compared with free spray, a much stronger pumping effect was generated for ST duct spray followed by CD duct spray; Less flow interaction with the spray body inside the ST duct, retaining more energy for spray development; A much stronger flow interaction was noted as the external gas was sucked into the expanding section of the CD duct, produce the local air vortexes in the narrow inner wall space of the CD duct, leading to the promoted spray diffusion and development with a wider spray cone angle. These phenomena from CD duct spray were beneficial for achieving a more sufficient fuel-air mixing process.

In-vivo and in-vitro effectiveness of three insecticides types for eradication of the tick Rhipicephalus sanguineus in dogs.

Background:External parasites contribute to extensive harmful impacts on their hosts which is why control and eradication of external parasites have been included in all biosecurity plans of dog houses.Aim:To evaluate the in-vitro and in-vivo effectiveness of chemicals like Doramectin injectable and Fipronil 50 mg/ml drops and herbal mixes eco-friendly insecticides like phenylpyrazole–garlic–camphor mix spray for combating the external parasitism in dogs and their influence on the hematological, biochemical, and cortisol (CORT) profiles.Method:The in-vitro effectiveness of the insecticides was conducted by using a total of 216 developmental stage Rhipicephalus sanguineus (72 adults, 72 larvae, and 72 eggs) designed into three replicates of petri dishes (3 plates × 8 units × 3 stages/replicate); each replicate was exposed to 1 ml insecticide. The number of surviving ticks was recorded after 0, 2, 4, 8, 16, and 24 hours. Sixteen Rottweiler male dogs aged 1 year and 45.5 kg were divided into four groups. Three groups (G1, G2, and G3) were experimentally infested with R. sanguineus ticks 3–4 weeks post-dog arrival and kept under observation from zero-time of experimental infestation for 1–2 weeks. The three experimentally infested dog groups were treated with Doramectin injectable, Fipronil 50 mg/ml drops, and phenylpyrazole–garlic–camphor mix spray, respectively, and the fourth group was designed as a negative control. A total of 144 samples, including 48 ethylenediaminetetraacetic acid blood, 48 whole blood, and 48 sera samples, were collected.Results:The in-vitro efficacy revealed highly significant (p < 0.01) 100% killing efficacy that was achieved after 8 hours in Doramectin and Fipronil 50 mg/ml and 24 hours in phenylpyrazole–garlic–camphor mix. The in-vivo trials revealed highly significant (p < 0.01) improvements of red blood cells, hematocrit, mean corpuscular hemoglobin concentrations, platelets, total and differential leukocytic counts, erythrocyte sedimentation rates in the second hour, total protein, creatinine, alanine aminotransferase, urea, glucose, triglycerides, total cholesterol, and CORT levels in the 2-week (P1) and 4-week posttreatment (P2) samples in Dormectin, Fipronil 50 mg/ml, and phenylpyrazole–garlic–camphor mix-treated dogs with more pronounced recovery in phenylpyrazole–garlic–camphor mix spray-treated dogs.Conclusion:The insecticides were able to provide a high level of protection against experimental infestation with concern to the different modes of application. Phenylpyrazole–garlic–camphor mix spray (eco-friendly) achieved higher insecticidal action compared to the chemicals.

Numerical Study of the Spray Mixing and Combustion in the Near-Wall Region with Thermal Barrier Coating

Numerical Study of the Spray Mixing and Combustion in the Near-Wall Region with Thermal Barrier Coating