Conventional Spray Research Articles

Thermal effects of immersion and ultrasonic on spray cooling in the boiling zone

This study examines the synergistic effects of ultrasound and immersion on spray cooling, highlighting cavitation and acoustic flow mechanisms. Experiments evaluated boiling zone variables. Compared heat transfer in conventional spray cooling (SC), immersion spray cooling (ISC), and immersion ultrasonic spray cooling (IUSC). The results demonstrate that both ultrasonic application and immersion conditions in boiling environments can significantly enhance heat transfer in certain cases. Spray height experiments show SC achieves its highest heat transfer efficiency at a specific spray height, while ISC and IUSC demonstrate superior performance at higher heights. Moreover, at higher spray heights IUSC increases the SC heat transfer efficiency by 17.07 %. The findings also demonstrate that spray cooling efficiency is notably influenced by the flow rate and heat flow density, exhibiting considerable improvements especially in scenarios of low flow rates and high heat flow densities. Moreover, lower water temperatures improve temperature-controlled immersion spray cooling (TCISC) and temperature-controlled immersion ultrasonic spray cooling (TCIUSC) efficiency. At higher water temperatures, TCIUSC outperforms TCISC, with an enhancement observed at up to 9.26 % at a water temperature of 20 °C. This study provides a new direction for spray cooling enhanced heat transfer.

Improvement of aerosol spray scavenging efficiency by pre-injecting electrically charged water mist

Efficient aerosol scavenging is crucial for gas purification to reduce environmental pollution in various chemical industries. In nuclear reactor decommissioning, especially for damaged reactors after severe accidents like Fukushima Daiichi, controlling radioactive aerosol generation and dispersion is essential. Radioactive aerosols sizing from 0.1 to 1 μm are expected during containment cleaning and fuel debris retrieval processes. To ensure safe decommissioning and mitigate environmental radioactivity, a containment water spray system is used for aerosol scavenging. However, conventional water spray has low efficiency for these submicron aerosols. Our recent experiments at UTARTS demonstrated that pre-injection of water mist enhances scavenging efficacy by increasing aerosol size and hydrophilicity through aerosol-mist agglomeration prior to spraying. On this basis, in this study, we introduced an innovative method using electrically charged water mist, which significantly facilitates aerosol-mist agglomeration through additional electrostatic coagulation, further improving scavenging efficacy (maximum 35 % in current configurations). The present experimental results attained under various mist conditions and charging configurations provided insights into optimizing the mist charging system. Our developed technology is expected to be useful in radioactive aerosol control during damaged reactor decommissioning and has potential applications in other environmental chemical engineering processes.

Comparison of energy consumption and probiotic stability with pilot scale drying processes

The production of dried probiotics offers multiple advantages including expanded storage options, ease of transportation, enhanced stability, formulation support, and incorporation into a variety of finished products. As probiotic use and application areas increase, the demand for lower production costs and increased product stability follows. The most common methods for drying include lyophilization and spray drying. Lyophilization offers high preservation of viability at the expense of production speed, while spray drying provides high throughput drying with greater loss of probiotic viability. Newer processes, such as electrostatic spray drying, have the potential to bridge the gap. The aim of this study was to evaluate the energy consumption and viability of Lacticaseibacillus rhamnosus GG (LGG) with pilot-scale conventional spray drying, electrostatic spray drying, and lyophilization. Energy consumption of the primary utilities was monitored along with LGG viability immediately and 8–12 weeks after drying. With regards to removal of water, conventional spray drying was the most energy efficient (1.2 kWh/L), followed by electrostatic spray drying (10.9 kWh/L) and lyophilization (16.9 kWh/L). When normalized against recovered viable LGG, electrostatic spray drying was the most efficient at 4.6 × 1010 CFU/kWh, followed by lyophilization and conventional spray drying at 1.1 × 1010 CFU/kWh and 4.8 × 107 CFU/kWh, respectively.

Analysis of the CO2 + C2Cl4 mixture in high temperature heat pumps: Experimental thermal stability, liquid densities and cycle simulations

Transcritical heat pumps working with CO2-based mixtures with a low-volatility dopant are found to achieve good performances in thermally integrated heat pumps, especially when sensible heat sources and heat sinks are considered. This paper introduces in literature tetrachloroethylene, C2Cl4, as CO2-dopant for the mixture to be adopted as working fluid in high temperature heat pumps. To calibrate the thermodynamic model used in the cycle simulations, an experimental characterization on the mixture is proposed: liquid densities of the mixtures are measured, in a wide range of concentration, optimizing the binary interaction parameter of the Peng Robinson equation of state. Moreover, the thermal stability of pure C2Cl4 is experimentally evaluated, identifying the maximum allowable compressor outlet temperature between 200 °C and 250 °C, with a decomposition rate below 1 %/year if the fluid is kept at temperatures around 200 °C. Then, the potentialities of this very high temperature heat pump are assessed in spray dryer applications: a coefficient of performance around 3.38 is obtained for a conventional spray dryer plant, corresponding to 73 % of second law efficiency, considering an air flow heated from ambient temperature to 200 °C as the sink, while cooling the sensible heat source, available at 76 °C, below 30 °C. As term of comparison, the same system adopting propane, instead of the CO2 + C2Cl4 mixture, would achieve a coefficient of performance and second law efficiency of 2.94 and 64 %, respectively.

Conventional and Nano-Zinc Foliar Spray Strategies to Improve the Physico-Chemical Properties and Nutritional and Antioxidant Compounds of Timor Mango Fruits under Abiotic Stress

Zinc deficiency is common under heat stress, and further research is needed to determine how to enhance the fruit quality of mango trees through the use of three forms of zinc, namely Zn-NPs, zinc sulfate (ZnSO4), and chelated zinc (Zn-chelated), as a foliar spray. This research was carried out using ten treatments to investigate the effect of zinc forms on the fruit quality of Timor mango trees. With a few notable exceptions, every fruit quality measurement (physical characteristics, chemical properties, mineral contents, and antioxidant compounds) responded to every treatment looked into; however, the extent of the reaction differed depending on the fruiting measurement. Furthermore, the Zn-NPs created a larger difference in the fruiting measurements than the ZnSO4 and Zn-chelated forms. ZnO NPs at 100 ppm ranked first, followed by ZnO NPs in the first spray and zinc EDTA in the second spray, followed by ZnO NPs in the first spray and ZnSO4 in the second, for all mineral content and antioxidant compound measurements and most of the fruit physico-chemical characteristics. In contrast, the lowest levels of minerals and antioxidant compounds and most of the fruit physico-chemical characteristics were found in the controls. The outcomes of the other treatments after the three treatments lay somewhere between these two extremes, and this pattern was detected throughout two seasons. Spraying Timor mango trees with nano, chelated, and sulfate zinc can be considered a safe and environmentally friendly natural method for improving fruit quality in abiotic stress regions.

Cleaning strategies for 3D-printed porous scaffolds used for bone regeneration fabricated via ceramic vat photopolymerization

Vat photopolymerization has gained prominence in bone tissue engineering owing to its capability to fabricate intricate structures that closely mimic the natural bone tissue. Thorough cleaning of uncured ceramic slurry from the as-printed structures is essential, as the presence of residue within the structure can obstruct pores during sintering. Given the limitations of conventional spray cleaning for these structures, this study seeks to investigate alternative cleaning approaches. Specifically, the efficacy of dibasic ester (DBE) and LithaSol 80, coupled with ultrasonic and soaking methods, is examined to identify optimal strategies for the thorough removal of viscous residual slurry (LithaBone HA 480). To examine the effect of temperature on cleaning ability, printed scaffolds were soaked in the cleaning solutions at 23, 30, 40, and 50 °C for 24 h. Based on the results, 50 °C was chosen as the temperature for further analysis while using both soaking (24, 48, 72 and 96 h) and ultrasonic (5, 15 and 30 min; 1, 2, 3, and 4 h) as the cleaning methods. The cross-sectional image of the scaffolds showed that at least 48 h and 30 min is required for effective cleaning with soaking and ultrasonic, respectively. Microstructure analysis of scaffolds cleaned with LithaSol 80 revealed smoother surfaces, while scaffolds treated with DBE showed visibly contracted pores with peeling effect suggesting that DBE exerts a more aggressive action on the cured slurry in contrast to LithaSol 80. Notably, significant difference in mass loss was observed between scaffolds treated with LithaSol 80 and DBE. The significantly higher mass loss observed with DBE suggests that it not only impacts uncured slurry but also possibly affects cured slurry. Accordingly, the results indicate that DBE is notably more effective in cleaning; however, LithaSol 80 is more appropriate for maintaining structural integrity combined with soaking cleaning method. No significant difference was observed in compressive strength between most sintered scaffolds.

Cold Sprayed Copper-Diamond Composites for Thermal Management of Semiconductor Packages

Thermal management is key to enabling increasingly powerful chips and heterogeneous integrated 2.5D/3-D systems. Composite materials with high thermal conductivities that can be placed at different levels of proximity to the die provide new solutions for heat dissipation. Here we report the fabrication of thick copper-diamond composite films using cold spray, which is a high-throughput, low-thermal-budget deposition technology. In cold spray, feedstock micro powder is accelerated in a specially designed nozzle by a heated pressurized gas and adheres to the substrate upon high-speed impingement. This process achieves higher deposition rates than other methods used in semiconductor manufacturing (such as electroplating). It also produces films that are denser and much less porous than ones produced by conventional thermal spray techniques. In this work, we first use process and thermal simulations to determine the requirements of the micro diamond powder feedstock, including the diamond core size, metal-clad thickness, core-clad interfacial resistance, and volume fraction to enable the cold spray of copper-diamond composites with thermal conductivities that are higher than copper. Subsequently, we perform a systematic characterization of the diamond powders from several suppliers, including the purity, metal oxygen content, particle morphology, and metal-clad adhesion. This characterization reveals the challenges of meeting all the specs using currently available diamond powders. Finally, we cold spray copper-diamond composite films on a variety of substrates with tunable thicknesses between 100 mm and 2 mm, achieving a thermal conductivity that is approximately 10% higher than cold-sprayed pure copper. Further improvement of the thermal properties relies on continued innovation in powder surface modification and powder storage/shipping methods.

Design and Testing of a Fruit Tree Variable Spray System Based on ExG-AABB

This paper addresses the issue of pesticide waste and low utilization rates resulting from traditional plant protection via spraying operations, which apply equal dosages to different targets or to different parts of the same target. To tackle this problem, we designed a variable fruit tree spraying system based on the ExG-AABB (excess green and axis-aligned bounding box) algorithm. We used a Kinect depth camera to capture information about the fruit tree canopy and constructed a spray flow model using pulse width modulation and variable spray control technology. Variable multi-nozzle spraying was guided by combining this canopy data. We evaluated the accuracy of each model in calculating canopy volume by comparing the coefficient of determination (R2) and root mean square error (RMSE) of the ExG-AABB with the slice convex hull method, voxel method, three-dimensional alpha-shape method, and QuickHull method. The ExG-AABB algorithm had the highest R2 value (0.9334) and the lowest RMSE value (0.0353 m3) among the five models, indicating that it most accurately reflects the true volume of the fruit tree canopy. This validates the effectiveness of the ExG-AABB algorithm in calculating canopy volume. We established a correlation model between canopy volume and spray volume, designed a canopy-adaptive layering method based on point cloud processing, and achieved precise calculation of nozzle flow. Comparative field experiments were conducted to analyze the spray coverage rate and observed flow, thereby evaluating the spraying effect of this variable spraying system. The experimental results showed that compared to conventional continuous spraying, this variable spraying system not only achieves more uniform spray coverage but also significantly reduces pesticide usage by 48.1%. Furthermore, through system optimization, the average coverage rate of the middle layer of the canopy decreased by 17.53%, effectively reducing the phenomenon of overlapping spraying from multiple nozzles and improving spraying efficiency.

Influence of Solvent Relative Permittivity in Swab Spray Mass Spectrometry.

The influence of solvent properties on ion generation by swab spray ionization was investigated. The ability of a variety of solvents of different relative permittivity, surface tension, and viscosity to form a stable and reproducible electrospray was examined. It is demonstrated that in swab spray ionization, a crucial balance between solvent composition, applied potential, and the solvent flow fed to the swab head must be maintained. The solvent composition was found to significantly affect the shape of the Taylor cone and the emerging cone jet, which eventually have an impact on the resulting ion yield. The results indicate that the relative permittivity of solvents measured under standard conditions is the main factor governing jet shaping, and consequently, the ionization efficacy. Short jets, which are required for maximum ion yield, were observed for solvents with relative permittivity εr higher than 25. Solvents exhibiting lower relative permittivity required the addition of 20% to 60% methanol to limit the jet length and to avoid the ineffective dripping pulsation. The observed effects were compared to conventional electrospray ionization and paper spray ionization.

Microstructure and wear resistance of cold sprayed CoCrFeNi HEA coatings: Influence of powder particle size and spraying temperature

This study focuses on the successful fabrication of three distinct types of CoCrFeNi high entropy alloy (HEA) coatings through cold spray (CS) technology, with an emphasis on analyzing the impact of varying crucial CS parameters (spraying temperature and the range of powder particle size), on the coating's microstructure and tribological properties. Contrasted with conventional thermal spraying techniques, lower operational temperature in CS safeguards the materials from undergoing oxidation or phase transitions that are typically induced by high-temperature conditions. Additionally, the high-velocity impact of particles onto the substrate within CS process triggers plastic deformation, resulting in the creation of coatings that are characterized by heightened hardness, and greater density. Such coatings exhibit significantly enhanced performance and durability. The cocktail effect observed in CoCrFeNi HEA is reflected in a suite of exceptional properties that markedly surpass those exhibited by traditional alloys. Chiefly, this phenomenon is manifested through the alloy's exceptionally high hardness and dense structure, positioning CoCrFeNi HEA as a promising candidate for applications in high-wear scenarios. Experimental outcomes indicate that when smaller powder particles and higher spraying temperatures are employed, the porosity of CSed CoCrFeNi HEA coatings was observed to decrease by nearly an order of magnitude, concomitant with a 22.46% enhancement in microhardness. This improvement in microhardness translates into a significant reduction of over 72% in the wear rate, underscoring the positive correlation between enhanced microstructural integrity and wear resistance properties. By meticulously tuning spraying temperature and powder particle size, the resulting microstructure can be rendered increasingly dense and refined.

Liquid-fueled high-performance burner utilizing a coarse porous matrix

In this study, a kerosene-fueled premixed burner system with a thick and large pore-sized (“coarse”) porous matrix was developed to achieve less-soot stable premixed combustion with variable combustion loads, i.e., turn-down ratio, TDR, defined as the ratio between the maximum and minimum loads. The present burner system mainly consists of the thick and coarse porous matrix made by packed ceramic balls of 8 mm-diameter, which acts as a vaporizer, mixer, and flame holder. The liquid fuel is fed into the porous matrix along with air. As the air and vaporized fuel are supplied toward the top-end (surface) of the porous matrix, a premixed flame is formed at this surface. Benefits of the adopted porous matrix include reduced wettability of the liquid fuel to pores of the porous matrix, which prevents its direct supply to the flame, promotes vaporization and mixing, and functions as a flame holder, allowing the flame to be sustained within the porous matrix. Combustion experiments were then carried out under various equivalence ratios (φ) between 0.47 and 1.34, and temperature measurement was conducted to evaluate the vaporization capability within the porous matrix. The experimental results confirmed that the quasi-steady and stable premixed combustion across the entire surface of the porous matrix throughout the burning event was successfully achieved under all φ values considered in this study. A simplified (one-dimensional) analytical model was developed to examine achievable range of TDR. It was found that the expected achievable TDR was higher than the value for the conventional spray combustion technology (∼ 6). Thus, the present burner system with a thick and coarse porous matrix was effective for attaining stable premixed combustion and a high TDR.

Evaluating the feasibility of powder milk production by pulse spray drying: An approach on sensory properties, toxicological assessment, and microbial inactivation

The potential of a new spray drying technology (pulse spray drying, PSD) was explored in drying milk, using two outlet temperatures. Sensory attributes, instrumental color properties, and volatile compounds were examined. Additionally, the effect of PSD on the food's chemical safety was measured by CALUX® bioassays. For these approaches, milk was also dried by conventional spray drying (SD) and lyophilization (LYO). Finally, the impact of PSD on the microbiological load was investigated using Pediococcus acidilactici ATCC 8042, as a non-pathogenic surrogate of enteric pathogens. In sensory analysis, reconstituted PSD samples were scored with higher color, odor, and flavor intensities than LYO and SD. Volatiles like γ-hexalactone, acetic acid, and ethyl acetate could have contributed to these particularities. Accordingly, instrumental color revealed differences between the four treatments, showing a more evident yellowish coloration and higher saturation in PSD milk. Cytotox, PXR, and p53 CALUX® results in PSD samples ranged from 0.11 to 0.21 μg Tributyltin acetate eq./g, 0.30–0.51 μg Nicardipine eq./g, and were under quantification limit, respectively. These findings indicated that PSD does not pose an increased toxicological risk compared to other drying technologies. Viability results of Pediococcus acidilactici during PSD showed that the higher the outlet temperature, the lower the cell viability. In conclusion, all data raised in this study evidenced that PSD could be used in milk drying without compromising its quality and safety. Industrial relevanceConsidering the low energetic consumption described in several works, pulse spray drying could be a promising approach for the food sector. In addition, it may play a relevant role in overcoming the limitations of conventional spray dryers in terms of viscosity. The results obtained in this study are one of the first in this field and show the feasibility of milk powder production without compromising its quality and safety.

Intercomparison of drone and conventional spraying of macro and micro nutrients on growth yield and quality of Tuberose (Agave amica Medik.) cv. Arka Prajwal

Intercomparison of drone and conventional spraying of macro and micro nutrients on growth yield and quality of Tuberose (Agave amica Medik.) cv. Arka Prajwal

Development of a proliposomal pretomanid dry powder inhaler as a novel alternative approach for combating pulmonary tuberculosis

Multidrug-resistant tuberculosis (MDR-TB) and extensively drug-resistant tuberculosis (XDR-TB) continue as public health concerns. Inhaled drug therapy for TB has substantial benefits in combating the causal agent of TB (Mycobacterium tuberculosis). Pretomanid is a promising candidate in an optional combined regimen for XDR-TB. Pretomanid has demonstrated high potency against M. tuberculosis in both the active and latent phases. Conventional spray drying was used to formulate pretomanid as dry powder inhalers (DPIs) for deep lung delivery using a proliposomal system with a trehalose coarse excipient to enhance the drug solubility. Co-spray drying with L-leucine protected hygroscopic trehalose in formulations and improved powder aerosolization. Higher amounts of L-leucine (40–50 % w/w) resulted in the formation of mesoporous particles with high percentages of drug content and entrapment efficiency. The aerosolized powders demonstrated both geometric and median aerodynamic diameters < 5 µm with > 90 % emitted dose and > 50 % fine particle fraction. Upon reconstitution in simulated physiological fluid, the proliposomes completely converted to liposomes, exhibiting suitable particle sizes (130–300 nm) with stable colloids and improving drug solubility, leading to higher drug dissolution compared to the drug alone. Inhalable pretomanid showed higher antimycobacterial activity than pretomanid alone. The formulations were safe for all broncho-epithelial cell lines and alveolar macrophages, thus indicating their potential suitability for DPIs targeting pulmonary TB.

Spherical nanocrystalline ScYSZ thermal barrier material by a novel supersonic plasma spheroidization method: Simple synthesis and excellent performance

The performance of plasma sprayed thermal barrier coatings (TBCs) is strongly dependent on the quality of the feedstock powders, which usually are fabricated by conventional spray drying and multi-step sintering methods. In this work, a novel supersonic plasma spheroidization technology was employed to fabricate the spherical nanocrystalline Sc2O3-Y2O3 co-stabilized ZrO2 (ScYSZ) powder. The deformation process from the irregular powder to the spherical one was stimulated by the COMSOL phase field simulation. The results suggested that the original irregular pyrolysis products of ScYSZ precursors were aggregated into spherical powders by plasma spheroidization technology. The COMSOL simulations verified that the powder changed from irregular particles to spherical ones. The spheroidized ScYSZ particles exclusively consisted of non-transformed t’-ZrO2 phase and showed good fluidity, smooth surface and high apparent density, which were expected to have a broader application prospect in the field of TBCs and other ceramic coatings.

Comparative Study of Electrochromic Supercapacitor Electrodes Based on PEDOT:PSS/ITO Fabricated via Spray and Electrospray Methods.

PSS stands out as a leading commercial conducting polymer due to its excellent water dispersibility, controllable miscibility, adjustable conductivity, and ability to form films through various techniques. This study investigates the electrochemical and electrochromic performance of electrodes prepared by depositing PEDOT:PSS onto ITO surfaces by using two distinct methods: conventional spray coating and electrospray deposition. Detailed characterization of the prepared electrodes was performed by using atomic force microscopy, scanning electron microscopy, Fourier-transform infrared, and Raman spectroscopy techniques. Our findings reveal that electrodes fabricated via electrospray deposition (PEDOT:PSS/ITO electrode_2) significantly outperform those made by spray coating (PEDOT:PSS/ITO electrode_1). Specifically, electrode_2 exhibits a capacitance of 1678.60 μF cm-2, compared to 826.14 μF cm-2 for electrode_1, at a current density of 10 μA cm-2. PSS electrodes exhibit areal energy densities of 0.41 and 0.84 mW h cm-2, along with power densities of 4.96 and 4.97 μW cm-2, respectively. Moreover, electrode_2 demonstrates a high coloration efficiency of 84.32 cm2 C-1 and fast response times of 1.36 s for coloration and 0.98 s for bleaching. This study highlights the advantages of electrospray deposition over traditional methods, showcasing the potential of electrospray-prepared PEDOT:PSS electrodes for use in multifunctional energy storage devices.

High performance coating formulation using multifunctional monomers and reinforcing functional fillers for protecting metal substrate

Purpose Effects of corrosion are very dire and mitigation of corrosion holds prime importance. Protective coatings play major role in preventing corrosion of metals and coating application is the most convenient, economical and quick solution. The purpose of the study is development of protective coatings to effectively mitigate corrosion of metal components. Design/methodology/approach A high-performance anticorrosion coating was prepared using multiple monomers and paste of functional and reinforcing fillers with extenders to protect metal components from corrosion in aggressive environmental conditions. The structures of copolymers synthesized with multiple monomers were studied by the NMR and FT-IR spectroscopic techniques. The percentage conversion of different proportions of various monomers was estimated using gas chromatography technique. The functional paste to impart superior anticorrosion properties was prepared using various functional and reinforcing fillers. The final coatings were prepared by mixing these resins with functional paste in various proportions. Findings The prepared anticorrosion coating was tested for high-performance mechanical and chemical properties and it was witnessed that the said coating offered desired performance properties needed for protecting metal components from corrosion. Research limitations/implications As such it is overcoming drawbacks of two pack systems and thus has almost no limitations or implications for application on metal substrate. Practical implications Being formulated as a single pack, it is free from drawbacks otherwise involved in two pack system of conventional paints. The coating system developed is very easy to apply using conventional tools, namely, brush, spray and roller techniques. The formulation is made in such a way that it has fast-drying properties. Makes painting or coating operations cost effective and confirm the performance. Social implications The findings of the research have anticorrosion nature that can enhance the life span of the substrates. It is specially designed for metal substrate and can protect metal substrate from corrosion in most aggressive conditions. Thus, it helps to reduce losses due corrosion and increase safety of metal structures and human being as well. As it is based on conventional material but with new formulation and technology, it has commercial possibilities to explore. Originality/value Unlike conventional protective coating systems, the said coating offered disruptive features like single pack systems and fast drying at ambient temperature along with high-performance properties. The coating formulation was observed to have a great importance in industry for effective corrosion mitigation and to reduce losses due to corrosion.

Rapid preparation of full color spectrum structural color coatings with iridescence effects via spray methods

Differing from conventional spray methods that only produce amorphous photonic crystals, this study innovatively achieves the ordered assembly of poly(styrene-methyl methacrylate-acrylic acid) (P(St-MMA-AA)) microspheres into photonic crystals on the substrate surface by adjusting the spray distance, a simple parameter. The resulting coating exhibits a uniform and iridescent structural color. Simultaneously, employing this technique, P(St-MMA-AA) microspheres with three different diameters (234 nm, 178 nm, and 152 nm) were mixed pairwise and co-organized in an ordered manner on the substrate surface. By adjusting the mass ratio of the two types of microspheres, structural color coatings covering the full visible spectrum were facilely and efficiently prepared. The coatings exhibit iridescence, and the structural colors are true colors with high color quality. Additionally, violet, unattainable in traditional color mixing systems, was achieved. The structural color coatings obtained in this study demonstrate promising applications in areas such as environmentally friendly finishes, optical anti-counterfeiting, and true-color displays.

In silico Screening of Plectranthus amboinicus and Hyptis suaveolens Phyto-chemicals: Novel Repellents Targeting Odorant Binding Proteins of Aedes aegypti and Aedes albopictus

Background and Aim: Mosquitoes significantly threaten public health, transmitting dangerous diseases to humans and animals. Conventional insecticide spraying, while common, has limitations in effectively controlling vector-borne diseases. Many chemical pesticides harm humans and animals, and some persist in the environment and cause toxic effects. Recently, there has been renewed interest in plant-based products due to concerns about insecticide re-sistance, cross-resistance, potential toxicity associated with synthetic options, and rising costs. Therefore, this study aimed to screen the Plectranthus amboinicus and Hyptis suaveolens phy-tochemicals targeting the odorant binding proteins (OBPs) of Aedes aegypti and Aedes albopic-tus. Methods: In this study, we conducted molecular docking analyses using specific plant-derived compounds from H. suaveolens and P. amboinicus. Results: We focused on the interaction of these compounds with OBPs from dengue and chikungunya vectors (Aedes aegypti and Aedes albopictus). The selected phytochemical com-pounds exhibited strong binding with the OBP of both Ae. aegypti and Ae. albopictus. Tetrahy-drofuran-2-carboxylic acid, Carvacryl acetate, and Brallobarbital showed high binding affinity and significant interaction with Ae. aegypti. Tetrahydrofuran-2-carboxylic acid and 3-Methyl-4-isopropylphenol also demonstrated substantial binding affinity and effective interaction with Ae. albopictus OBP. Conclusion: These findings suggest that the identified compounds can potentially disrupt the attraction of mosquitoes to humans, thus reducing human-vector contact. They may offer a promising alternative for developing natural and efficient mosquito repellents, surpassing cur-rently used synthetic options like N, N-diethyl-meta-toluamide, and other conventional repel-lents.

Development of improved spray system with effective electrical electrodes for aerosol removal: An experimental study in UTARTS facility

Safe reactor decommissioning, especially for damaged Fukushima Daiichi (1F) nuclear power plants, is vital for environmental safety. Key challenges include remotely cleaning radiation hotspots and cutting fuel debris within the damaged primary containment vessel. However, submicron radioactive Aerosol Particles (APs) can be generated, thus necessitating effective aerosol control and removal to avoid radioactive environmental pollution and reduce radiation exposure risks during 1F decommissioning. Flue gases containing submicron APs that result in environmental pollution can also generated from other industrial works, e.g., coal, mining and chemical sectors. Conventional water spray is difficult to scavenge these small APs. Although previous studies showed the effectiveness of charged droplets on accelerating aerosol removal, the charging configuration is also important to scavenging performance. Hence, this study performs aerosol scavenging experiments in our UTARTS facility with varying induction electrode designs. Experimental results show the saturation of scavenging efficiency at high voltage and indicate the importance of charging polarity. Moreover, proper configurations of electrode position, geometry and material are studied and discussed. Our findings can be beneficial for the improvement of spray system for aerosol removal to mitigate radioactivity release and minimize contaminated water production and have implications for gas purification in various environmental and chemical industries.