Spray Bar Research Articles

Optimized design of smart toilet spray bar flow channel based on CFD

Currently, there are significant issues with the intelligent toilets available on the market, such as a large swing of the spray bar when spraying water column and eccentricity. This paper presents four optimization schemes for the intelligent toilet spray bar channel by analysing and redesigning a specific model. Computational Fluid Dynamics (CFD) technology was employed to analyse the water flow conditions inside the spray bar of the intelligent toilet. The calculation results indicate that for the same water inlet flow rate, the optimal structure in optimization scheme 1 is the block with a length (L) of 1.5 mm. In optimization scheme 2, the optimal structure is the block located at position (3). In optimization scheme 3, the optimal structure is a 15° rotation, which exhibits the least swirls and pressure loss while maintaining the prototype structure. When the prototype structure is modified, the optimal structure in optimization scheme 4 is the excision bend pipe. This structure exhibits the lowest swirl number and pressure loss among all the optimization schemes. The determined structure offers valuable insights for enhancing the flow characteristics of the improved product.

Preliminary design and analysis of an afterburner module

In this study, design calculations and calculations of afterburner used in jet engines are presented by evaluating the results of analytical and computational analysis. Afterburner inlet values of 1050 K temperature, 300 kPa pressure and 3.6 kg/s mass flow rate are taken as the design conditions. Maximum length and diameter are 500 mm and 200 mm, respectively, for the sections to be designed as length constraints within the scope of the conceptual design. The two-ring vee-gutter has 1.33 cm in diameter and 4.25 cm high. Jet A fuel is assumed to be injected into the core flow (90 degrees) from the spray bars. The spray is mounted in line with the vee-gutter to optimize the mixing of the flow. Analyses are performed for 4 cm between the spray bar and the vee-gutter. For the study, the GE J79 engine was examined from the literature and taken as a basis for the aerodynamic transition section design. Within the scope of TEKNOFEST 2023 Jet Engine Design Competition, a preliminary design of an afterburner module that can produce 700 pounds of thrust and has a life capacity of 25 hours should be realized in line with the design requirements and constraints. In the light of geometric constraints, one-dimensional combustion calculations of the module are made, and the parts are modelled using the relevant SolidWorks CAD program and these modelled parts are then transferred to ANSYS™ environment and the results and analyses are verified. The afterburner module flow analysis software program ANSYS™ is used to analyse the afterburner operation in both cold operating ranges (i.e. without combustion) using compressible, viscous and standard k-epsilon turbulence model. As a result, the effect of afterburner length on combustion performance is found to be significant. As a result of the calculations, afterburner length is found as 28.14 cm. It is found that the combustion efficiency is 81.5% and the temperature can be increased from 1050 K to 2044 K. The total pressure loss is 14.96% as pressure drop due to the geometric parameters and heat addition. The blockage ratio calculated due to the use of vee-gutter geometry is the most important parameter in the pressure drop. It is found that the jet engine producing 670 lbs (2981 N) of thrust when the afterburner is not working whereas it can provide a significant amount of power increment at the expense of a 50% increase in specific fuel consumption when the afterburner is active as well as providing a 738 lbs (3238 N) with a 10.1% thrust increase. The reason of the enhancement is mainly coming from the mixing effect of the vee-gutter on the flow structure.

Flow Channel Optimization to Improve the Performance of a Liquid–Gas Ejector for an Intelligent Toilet Spray Bar

Intelligent toilets can effectively remove odors and harmful substances from exhaust gases and wastewater, maintaining a fresh and clean indoor atmosphere, which is beneficial to the indoor environment and human health. Currently, research on intelligent toilets conducted by sanitary ware manufacturers is still in its early stages. Many of the intelligent toilets available on the market exhibit issues such as an excessive oscillation amplitude of the cleaning spray bar, premature breakdown of the water column, and inadequate air intake. The present study involves the analysis and redesign of a cleaning spray bar model for intelligent toilets. Additionally, several optimization schemes concerning the flow channel of the cleaning spray bar are proposed in order to enhance the performance of the liquid–air ejector. The computational fluid dynamics (CFD) technique is utilized to analyze the water flow characteristics within the cleaning spray bar of the intelligent toilet and to compare and evaluate the proposed schemes. The calculation results indicate that, for the same inlet flow rate, the optimal structure the block with a length of L = 1.5 mm and the block positioned (4). The swirl numbers of these two optimized models are 14.8% and 8.3% of the protype, respectively, while their air intake is 133% and 131% of the protype, respectively. The optimized solutions exhibited significant performance improvements when compared to the prototype. The computational results offer valuable insights for optimizing the flow characteristics of the enhanced product.

An internet of things prototype to quantify the lateral wheel path distributions of local roads in New Zealand

ABSTRACT The actual lateral wheel path distribution (LWD) on roads differs from the design assumptions. This leads to premature deterioration of chip-sealed pavements in the form of flushing and ravelling resulting in subsequent maintenance costs. The location of LWD is key to calibrating the variable-rate bitumen spray bar used to minimise flushing and ravelling during chip seal construction. Current methods used to estimate the location of LWD rely on visual inspection. This is subjective and reliant on individual expertise. This study aims to automate obtaining LWD by developing an Internet of Things (IoT) prototype to locate the LWDs. This prototype was tested by collecting LWDs from 22 locations in Christchurch, New Zealand. Results show that narrow roads exhibit a concentrated wheel path distribution. Specifically, increasing single lane carriageway width leads to a significant rise in the standard deviation (spread) and position of the LWDs among 22 locations investigated. Cycle lanes or parking bays significantly influence the location and distribution of LWD. There is no clear link between road camber and LWD. The findings can be used to improve the calibration of the variable-rate bitumen spray bar and inform pavement and traffic engineers to enhance construction and maintenance practices. .

Enhancing the efficacy of peracetic acid against Listeria monocytogenes and Listeria innocua on fresh apples using commercial acidic and alkaline cleaners

Peracetic acid (PAA) is a commonly used antimicrobial in brush-bed spray bar interventions during apple packing. Prior to sanitizer application on the brush-bed, specific fruit cleaners, such as Acidex Duo (AD), EpiClean (EC), Nature's Shield 220-ACL (NS 220), or Nature's Shield 330-ALK (NS 330), are used to remove of soil, debris, and natural wax from the surfaces of apples. This study evaluated the effectiveness of commonly used cleaners in the apple industry to improve the antimicrobial efficacy of PAA against Listeria monocytogenes on apple surfaces during brush-bed spray bar interventions. Granny Smith apples, 48 h post-inoculation, underwent submersion treatment with different cleaners, as well as PAA alone or in combination with the cleaners. A 30-sec treatment of 5.0% AD, 4.2% EC, 10.0% NS 220, and 10.0% NS 330 resulted in 0.65, 0.50, 0.68, and 0.51 log10 CFU/apple reduction of L. monocytogenes on apples, respectively. Incorporating AD, NS 220, and EC significantly enhanced the antimicrobial efficacy of an 80 ppm PAA intervention. The enhancing effects were not impacted whether the cleaner was applied consecutively with PAA (sequentially) or in combination with PAA (simultaneously), nor were they impacted by a post-treatment water rinse. A 30–120 s wash of 80 ppm PAA with AD, EC, and NS 220 at their suggested concentration resulted in 2.46–2.55, 1.87–2.03, and 2.34–2.48 log10 CFU/apple reduction of L. monocytogenes, respectively, compared to 1.39–1.64 log10 CFU/apple in PAA treatment alone. The inclusion of AD or NS 220 in 80 ppm PAA solution resulted in a reduction of 1.51–1.63 log10 CFU/apple of Listeria after 30–60 s brush-bed spray wash. This enhancement in efficacy was significant compared to the treatment with 80 ppm PAA alone, which resulted in a reduction of 0.94–1.03 log10 CFU/apple. This study demonstrated that using certain commercially available cleaners along with PAA can enhance the effectiveness of PAA in reducing L. monocytogenes on fresh apples.

Effect of a Reduced Oil Flow Rate on the Static and Dynamic Performance of a Tilting Pad Journal Bearing Running in Both the Flooded and Evacuated Conditions

Abstract The mechanical efficiency of rotating machinery improves as drag power losses in bearings reduce; hence, an operation mode that reduces the supplied flow brings immediate benefits. The paper presents measurements of the static and dynamic load performance conducted with a tilting pad journal bearing configured as flooded and evacuated, and supplied with flow rates from 150% to ∼25% (or lesser) of a nominal magnitude, proportional to shaft speed. The lubricant is ISO VG 46 oil supplied at 60 °C. The four pads bearing has center pivots with single orifice feeds for the flooded condition and spray bar injection for the evacuated condition. The shaft, 102 mm in diameter, operates at two speeds, 6 and 12 krpm (= 64 m/s surface speed), while a static load is applied between pads (LBP). The specific loads equal 345, 1034, and 2068 kPa. A reduction in flowrate makes both bearings operate more eccentrically. The evacuated bearing operates at a larger eccentricity, which for the lowest flowrate does not align with the direction of the applied load, hence displaying a sizable attitude angle. Pad subsurface temperatures are similar for both bearing configurations, although the evacuated bearing is colder by a few degrees Celsius. Drag power losses derived from the oil exit temperatures show the evacuated bearing produces up to ∼40% lesser power loss than the flooded bearing for a nominal oil flowrate. The bearings direct stiffnesses, Kxx and Kyy, increase with applied load and show little dependency on shaft speed. The evacuated bearing has lower magnitude stiffnesses, 20% or so lesser, than the flooded bearing. Damping coefficients, Cxx ∼ Cyy, reduce in magnitude as the flowrate decreases. In particular for low flow rates, 35% or lower, the evacuated bearing shows rather small (though highly uncertain) damping coefficients. For sufficiently small flow rates, operation at 6 krpm shaft speed and under the smallest applied unit load (345 kPa) produced subsynchronous shaft vibrations with a broad band spectrum (subsynchronous shaft vibrations (SSV) hash). The evacuated bearing produced SSV hash at flow rates equal to 30% or so of nominal, while the flooded bearing demanded very low flow rates (∼15% and lesser of nominal) to produce SSV hash. For both bearings, the SSV amplitude motions were rather small in amplitude. The experimental campaign demonstrates that tilting pad bearings (flooded and evacuated) can safely operate with a reduced flowrate (50% or so of nominal) to produce significant savings in drag power losses and without significant effect on the pads' metal temperatures that could affect the bearing long-term operation.

Design of field real-time target spraying system based on improved YOLOv5.

Deep learning techniques have made great progress in the field of target detection in recent years, making it possible to accurately identify plants in complex environments in agricultural fields. This project combines deep learning algorithms with spraying technology to design a machine vision precision real-time targeting spraying system for field scenarios. Firstly, the overall structure scheme of the system consisting of image acquisition and recognition module, electronically controlled spray module and pressure-stabilized pesticide supply module was proposed. After that, based on the target detection model YOLOv5s, the model is lightened and improved by replacing the backbone network and adding an attention mechanism. Based on this, a grille decision control algorithm for solenoid valve group on-off was designed, while common malignant weeds were selected as objects to produce data sets and complete model training. Finally, the deployment of the hardware system and detection model on the electric spray bar sprayer was completed, and field trials were conducted at different speeds. The experimental results show that the improved algorithm reduces the model size to 53.57% of the original model with less impact on mAP accuracy, improves FPS by 18.16%. The accuracy of on-target spraying at 2km/h, 3km/h and 4km/h speeds were 90.80%, 86.20% and 79.61%, respectively, and the spraying hit rate decreased as the operating speed increased. Among the hit rate components, the effective recognition rate was significantly affected by speed, while the relative recognition hit rate was less affected.

AN IOT PROTOTYPE TO COLLECT TRANSVERSE VEHICLE POSITION DATA FOR LOCAL ROADS

In New Zealand, most roads are chip-sealed over granular base pavements, which rely on the Transverse Variable Application Spray Bar (TVAS) during the resealing process. TVAS sprays a lower application rate of bitumen in the wheel path areas to limit flushing and uses a higher application rate outside of wheel path areas to limit raveling. Currently, this is carried out by visually identifying the wheel paths where flushing and raveling exist. This manual process is prone to human bias. Ideally, pavement resealing needs to be done before visible signs of distress appear. This study aims to automate obtaining lateral wheel path distribution (LWD) using an Internet of Things (IoT) prototype. This prototype is based on the Arduino platform, which was used to collect wheel placement distributions from vehicles on several sites in Christchurch, New Zealand. Results show that narrow roads exhibit a concentrated wheel path distribution. Additionally, vehicles tend to drive further away from the solid white shoulder line and closer together when parked cars are present. The results can be incorporated into the calibration of the TVAS and pavement design for improved construction and maintenance efficiency.

Sustainable Silage Maize Integrated Protection against the European Corn Borer Ostrinia nubilalis and the Corn Earworm Helicoverpa armigera Employing the Farm Irrigation System

Silage corn is an important source of feed in animal husbandry, often affected by the feeding action of diverse corn borers that can compromise harvest quality and quantity. According to the need to reduce the use of chemical insecticides, the main purpose of this study was to evaluate the efficacy of different IPM programs comparing microbial (Btk and baculovirus) and chemical control methods, alone or combined, against O. nubilalis and H. armigera. Assessments were based on counting the number of larvae, inspecting plants superficially and inside the stem, and estimating the derived damages. All tested products proved to be effective in containing the density of these lepidopteran species, with microbial control agents having comparable efficacy in respect to the reference chemical substances (lambda-cialotrina and chlorantraniliprole), even if periodic treatment repetition was required to ensure over-time protection until harvest. Both Btk and HaNPV were successfully applied by the irrigation system during flowering and fruit development periods, when plant height did not allow the use of a tractor-mounted spray bar. This biocontainment approach appears to be sustainable and technically compatible with farm needs.

Parametric optimization and analysis of thermodynamic venting system in liquid hydrogen tank under microgravity

This paper used the lumped vapor model to simulate the self-pressurization and thermodynamic venting process in the cryogenic liquid hydrogen tank with 90% filling rate under microgravity. Based on the orthogonal experiment, twenty-five cases with different parameters were designed. Daily evaporation rate and cooling capacity utilization efficiency were proposed to evaluate the exhaust loss during the jet process and depressurization efficiency during depressurization process. The four parameters of spray bar including exhaust rate, diameter of inner tube of heat exchanger, nozzle length and number of nozzles were optimized and the weight of influence on the daily evaporation rate and cooling capacity utilization efficiency was analyzed. Results showed that nozzle length and number of nozzles played a key role in the daily evaporation rate and cooling capacity utilization efficiency, while diameter of inner tube of heat exchanger had little effect. Under the same mass flow, smaller nozzle length, lower exhaust rate and fewer nozzles could increase the inlet velocity, thereby reducing the daily evaporation rate and improving the cooling capacity utilization efficiency. The thermal stratification could be eliminated well. In addition, arranging two nozzles up and down was more advantageous than arranging a single nozzle in the middle. The research results were useful for improving the efficiency of the thermodynamic venting system (TVS) and extending the propellant storage time in orbit.

A Review Paper on Design and Fabrication of Belt Oil Skimmer

Oil Skimming Although designs vary, all oil skimmers rely on specific gravity, surface tension and a moving medium to remove floating oil from a fluid’s surface. Floating oil and grease cling to skimming media more readily than water, and water has little affinity for the media. This allows skimming media in the shape of a belt, disk, drum, etc. to pass through a fluid surface to pick up floating oil and grease with very little water. This oily material is subsequently removed from the media with wiper blades or pinch rollers. Oil skimmers are simple, dependable and effective tools for removing oil, grease and other hydrocarbons from water and coolants. Often, an oil skimmer by itself can achieve the desired level of water purity. In more demanding situations, oil skimming is a cost-effective means of removing most of the oil before using more complicated and costly treatments such as coalescers, membrane filters and chemical processes. Grease skimming involves higher viscosity hydrocarbons. Oil skimmers must be equipped with heaters powerful enough to keep grease fluid for discharge. If the floating grease has formed into solid clumps or mats, a spray bar, aerator or mechanical apparatus can be used to break up grease mats and facilitate removal. This topic describes the development of the OS with typical working model.

PARAMETERS FOR MODELING PASSIVE SUSPENSIONS OF SPRAY BARS

The uniformity and quality of spraying depend on the stability of the spray boom, defined as the suspension system between the boom and the machine chassis. This paper presents a procedure for improving the performance of passive spray bar suspensions through parameter adjustment. Two multibody dynamics models of a tractor sprayer set were developed to evaluate their suspension systems: a rigid body dynamics model (RBDM) and a finite element model (FEM) using deformable bodies. To calibrate the models in the experiment, an accelerating force was applied to the suspension, and the displacements of the shock absorber and the rubber springs were monitored. The FEM is more suitable for the evaluation of the horizontal oscillations of the bar, based on root mean square (RMS) values and a standard curve used to evaluate the stability of the bar. The horizontal stiffness of the bar significantly influences the oscillatory displacement and must be included in the simulation models. Resizing the structure can reduce the horizontal oscillations of the bar.

Research on the application of binary-like coding and Hough circle detection technology in PCB traceability system

With the rapid development of smart devices, printed circuit board (PCB), as the core components of smart devices, not only proposed more and more demand for the quality and precision of their production, but also the controllability of their management and the traceability of manufacturing. The traditional processes for PCB including: acid–base corrosion, water washing, grinding and so on. Due to the traditional spray bar code, thunder engraving two-dimensional code and other methods cannot be used for PCB board identification, but the drilling method has been utilized. At present, the major methods for drilling identification and matrix drilling identification are time consuming, and low identification speed. To tackle this problem, in this paper, we combine the advantages of binary coding and the industry characteristics of PCB production, proposed a kind of binary-like code to identify the position of PCB production, in which, each digit of the binary code can be identified by four holes of a square with equal distance, and can represent the numbers from 0 to 9. Besides, fewer letters and the starting position of the code on the basis of few punching points. This method will greatly improve the efficiency of drilling identification. The system uses the photoelectric analysis module to automatically scan the hole array code on the penal (PNL) board to obtain the original image. Then, the CCD image is preprocessed, mainly including Gaussian filter for image smoothing and unsharp mask operator for image enhancement. Then, Hough detection algorithm is utilized to locate the hole, which can effectively identify the holes. Secondly, the horizontal and vertical directions of these points can be obtained according to the distance between the center points of each hole. Furthermore, the image is righted, and the starting position can be obtained. At the same time, Hough detection algorithm is used to segment the image threshold, and each character is decoded into a corresponding number. The simulation results show that the method is simple, accurate and effective. Finally, the identified digital coding sequences are compared with the database of online code reading application system, and the reliable identification and automatic identification trace-ability of PCB production are realized, and the automatic identification time is less than 1 s.

Research on the Influence of External Parameters of Fan-Type Nozzle on Water Jet Performance

At present, high-pressure water jet technology occupies a very important position in the automobile washing industry. Some automatic washers cannot meet the washing requirements in the washing process due to unreasonable arrangement of nozzles on their spray rods. Based on the theory of computational fluid dynamics (CFD), the internal and external flow field model of the nozzle are established in this paper. Fluent is used to simulate and analyze the flow field, and the external parameters of the nozzle on the side spray bar of the automatic automobile washer are optimized. The simulation results show that after the nozzle and the normal line of the automobile surface are inclined at a certain angle, the target surface is affected not only by normal striking force but also by tangential pushing force, which makes stains easier to remove. The washing effect is the best when the nozzle is inclined 30° to the normal line of the automobile surface. Increasing the nozzle inlet pressure will increase the dynamic pressure on the automobile surface, but the increase of dynamic pressure will decrease after increasing to a certain pressure. The inlet pressure has little effect on the area covered by water jet. The reasonable matching results of jet angle, nozzle spacing, and nozzle distance from the automobile surface (target distance) obtained by numerical simulation can not only make the automobile surface completely covered and cleaned but also ensure less jet interference and no waste of water from adjacent nozzles. The above research conclusions can provide a basic theoretical basis for the optimal design of automatic automobile washing.

Analysis of the Honeywell Uncertified Research Engine With Ice Crystal Cloud Ingestion at Simulated Altitudes

Abstract The Honeywell Uncertified Research Engine (HURE), a research version of a turbofan engine that never entered production, was tested in the NASA Propulsion Systems Laboratory (PSL), an altitude test facility at the NASA Glenn Research Center. The PSL is a facility that is equipped with water spray bars capable of producing an ice cloud consisting of ice particles, having a controlled particle diameter and concentration in the airflow. To develop the test matrix of the HURE, the numerical asw analysis of flow and ice particle thermodynamics was performed on the compression system of the turbofan engine to predict operating conditions that could potentially result in a risk of ice accretion due to ice crystal ingestion. The goal of the test matrix was to provide operating conditions such that ice would accrete either in the fan-stator through the inlet guide vane region of the compression system or within the first stator of the high-pressure compressor. The predictive analyses were performed with the mean-line compressor flow modeling code (comdes-melt) which includes an ice particle model. The HURE engine was tested in PSL with the ice cloud over the range of operating conditions of altitude, ambient temperature, simulated flight Mach number, and fan speed with guidance from the analytical predictions. The engine was fitted with video cameras at strategic locations within the engine compression system flow path where ice was predicted to accrete in order to visually confirm ice accretion when it occurred. In addition, traditional compressor instrumentation, such as total pressure and temperature probes, static pressure taps, and metal temperature thermocouples, were installed in targeted areas where the risk of ice accretion was expected. The current research focuses on the analysis of the data that were obtained after testing the HURE engine in PSL with ice crystal ingestion. The computational method (comdes-melt) was enhanced by computing key parameters through the fan-stator at multiple spanwise locations in order to increase the fidelity with the current mean-line method. The Icing Wedge static wet-bulb temperature thresholds were applied for determining the risk of ice accretion in the fan-stator, which is thought to be an adiabatic region. At some operating conditions near the splitter–lip region, other sources of heat (non-adiabatic walls) were suspected to be the cause of accretion, and the Icing Wedge was not applied to predict accretion at that location. A simple order-of-magnitude heat transfer model was implemented into the comdes-melt code to estimate the wall temperature minimum and maximum thresholds that support ice accretion, as observed by video confirmation. The results from this model spanned the range of wall temperatures measured on a previous engine that experienced ice accretion at certain operating conditions. The goal of this study is to show that the computational process developed on earlier engine icing tests can be used to provide an icing risk assessment in adiabatic regions for other engines.

The optimization of simulated icing environment by adjusting the arrangement of nozzles in an atomization equipment for the anti-icing and deicing of aircrafts

To investigate the aircraft icing problem, simulation of the high-altitude clouds as the icing environment becomes necessary. Clouds always contain many micro-scale subcooled droplets. The accurate control of the icing environment simulation is challenging. In this study, to optimize the icing environment simulation, the arrangement of 10 nozzles in the atomizer was adjusted. A model of the atomization equipment in an icing cloud simulation system was independently developed and fully experimentally validated with two parameters, the ice shape and the maximum ice thickness on the test rod. The error of maximum ice thickness, the maximum and mean deviations are 2.6%, 1.13 mm and 0.68 mm, respectively. Then, the performance of the icing environment at 6 different nozzle arrangements were simulated and analyzed. The spreading area of water droplets and the uniformity of liquid water content distribution were proposed to evaluate the simulated icing environment performance. For the best nozzle arrangement, the spreading area and the area-weighted average of liquid water content are 0.24009 m2 and 0.168 g/m3, respectively. For the worst case, the spreading area and the area-weighted average of liquid water content are 0.22511 m2 and 0.17056 g/m3, respectively. Additionally, increasing the horizontal distance between two nozzles in the middle spray bar adversely affects the performance of the simulated icing environment. Contributions of this study could effectively guide the realization of a better simulated icing environment.

Critical points affecting the microbiological safety of bell peppers washed with peroxyacetic acid in a commercial packinghouse

The washing stage from a bell pepper commercial packinghouse was assessed to study some of the critical control points related to bacterial cross-contamination. The washing line comprised two overhead spray bars applications: a pre-wash step without peroxyacetic acid (PAA), and a wash step with PAA. The physicochemical characteristics of the wash water and the bacterial quality and safety of the wash water and bell peppers (including aerobic mesophilic bacteria (AMB), Salmonella spp., and Shiga-toxigenic E. coli (STEC)) were studied. Additionally, the performance of commercial test methods (reflectometry, amperometric probe, chronoamperometric sensor) for measuring the residual concentration of PAA was examined. The bacterial load of the pre-wash water (8.7 ± 1.3 log cfu/100 mL AMB) was very high and thus peppers after the pre-wash showed a significantly higher bacterial load (4.9 ± 0.9 log cfu/g AMB) than the unwashed (3.8 ± 0.7 log cfu/g AMB) or the washed peppers (3.3 ± 0.8 log cfu/g AMB) (p < 0.05). However, no pathogenic bacteria were detected in bell pepper samples (n = 40), and only one water sample was confirmed positive for STEC (n = 64, 1.6% prevalence). The chronoamperometric sensor (PAASense) and the online amperometric probe showed similar results, while the reflectometry (Quantofix) significantly sub estimated (p < 0.05) PAA concentration. The results obtained highlight the need for interventions to improve hygiene in the washing line to ensure the microbiological quality and safety of bell peppers. The maintenance of optimal PAA concentrations in all the washing steps is critical for reducing the chance of water-mediated cross-contamination.

CHEMICAL CONTROL OF ASIAN SOYBEAN RUST AS A FUNCTION OF CULTIVAR, ROW SPACING AND SPRAY BAR SUPPORT SYSTEMS

Product deposition and foliar surface cover are highly impacting factors on the efficiency of foliar fungicides applied to soybean cultivars, due to their low mobility, with side effects on Asian soybean rust (ASR) control. Spray bar support systems, such as the air curtain (Vortex®) and the use of nozzles along the bar (Dropleg®), stand out as an alternative to obtain a better distribution of fungicide throughout the plant. In this study, two spray bar support systems (Vortex® and Dropleg®) were, therefore, evaluated and compared with the conventional spraying method based on the biological efficacy in ASR control. In order to do this, two harvests, with three spacing between rows and two cultivars were employed. Vortex® and Dropleg® spray bar support mechanisms do not effectively contribute to the optimization of Asian soybean rust control or to the grain crop yield, regardless of cultivar and row spacing. Decreasing the row spacing did not influence the level of control of Asian soybean rust, as the highest grain yield was obtained with the smallest spacing. The cultivar with genetic resistance to Asian rust showed lower levels of this disease, thus, greater control against the use of fungicides.

Thermal stratification suppression in reduced or zero boil-off hydrogen tank by self-spinning spray bar

Thermal stratification of cryogenic propellants under the condition of external heat leakage is a dominating factor pressurizing the storage tank, which hinders long-term on-orbit storage missions for future explorations. Whether a thermodynamic venting system or cryocooler is introduced to reduce the boil-off losses or even realize zero boil-off of the cryogens, an efficient mixing and heat-exchanging device is a prerequisite for eliminating thermal stratification. Usually, a subcooled stream is introduced, which is injected into the tank through the nozzles on a spray bar. Early research provided evidence that the cooling effect is related to the arrangement of the nozzles. In contrast to adopting a heavy plate spray bar to realize the temperature profile symmetry along the tank axis, this study proposes an assembly with a rotatable nozzle head to diminish the temperature non-uniformity in the tank. In this manner, over 70% of the spray bar payload can be saved compared to the plate configuration. A three-dimensional model was established to investigate the temperature distribution of liquid hydrogen at zero gravity in a tank containing such a rotatable sprayer, which was passively driven by the counterforce of the injection flow, and therefore excluded an extra power drive demand. The injection inlet velocity, as well as the length and quantity of the nozzle arms, were analyzed parametrically to optimize the destratification performance. By employing the self-spinning sprayer, the standard deviation of the temperature in the tank could be lowered, along with the benefits of a significant payload reduction and elimination of direct power input.

Enhanced Efficacy of Peroxyacetic Acid Against Listeria monocytogenes on Fresh Apples at Elevated Temperature.

Peroxyacetic acid (PAA) is the most commonly used antimicrobial in spray bar antimicrobial treatment during fresh apple packing and processing. However, there are limited data regarding its practical efficacy against Listeria monocytogenes on fresh apples. This study evaluated the antimicrobial activity of PAA against L. monocytogenes on fresh apples applicable to current industry practice, and further examined practical parameters impacting its efficacy to maximize the biocidal effects. Apples were inoculated with a three-strain L. monocytogenes cocktail at ~6.0 Log10 CFU/apple and then subjected to comparative antimicrobial treatments after 48 h post-inoculation. An 80 ppm PAA treatment, at 30-s and 2-min exposure, reduced L. monocytogenes on fresh apples by ~1.3 or 1.7 Log10 CFU/apple, respectively. The anti-Listeria efficacy of PAA was not affected by the water hardness and pH of PAA solution, while it improved dramatically when applied at elevated temperature. A 2-min exposure of 80 ppm PAA at 43 and 46°C resulted in a 2.3 and 2.6 Log10 CFU/apple reduction, respectively. A 30-s contact time of 80 ppm PAA at 43–46°C reduced L. monocytogenes on apples by 2.2–2.4 Log10 CFU/apple. Similarly, PAA intervention at elevated temperatures significantly strengthened its effectiveness against naturally occurring apple microbiota. PAA treatment at 43–46°C can provide a vital method to improve antimicrobial efficacy against both L. monocytogenes and indigenous microbiota on fresh apples. Our data provide valuable information and reference points for the apple industry to further validate or verify process controls.