Search Results (36)

Difficult, extreme operating conditions of parabolic antennas under precipitation and sub-zero temperatures require the creation of effective heating systems. The purpose of the research is to develop a multilayer coating containing two metal-ceramic layers, epoxy composite layers, carbon fabric, and an outer layer of basalt fabric, which allows for effective heating of the antenna, and to study the properties of this coating. The multilayer coating was formed on an aluminum base that was subjected to abrasive jet processing. The first and second metal-ceramic layers, Al₂O₃ + 5% Al, which were applied by high-speed multi-chamber cumulative detonation spraying (CDS), respectively, provide maximum adhesion strength to the aluminum base and high adhesion strength to the third layer of the epoxy composite containing Al₂O₃. On this not-yet-polymerized layer of epoxy composite containing Al₂O₃, a layer of carbon fabric (impregnated with epoxy resin) was formed, which serves as a resistive heating element. On top of this carbon fabric, a layer of epoxy composite containing Cr₂O₃ and SiO₂ was applied. Next, basalt fabric was applied to this still-not-yet-polymerized layer. Then, the resulting layered coating was compacted and dried. To study this multilayer coating, X-ray analysis, light and raster scanning microscopy, and transmission electron microscopy were used. The thickness of the coating layers and microhardness were measured on transverse microsections. The adhesion strength of the metal-ceramic coating layers to the aluminum base was determined by both bending testing and peeling using the adhesive method. It was established that CDS provides the formation of metal-ceramic layers with a maximum fraction of lamellae and a microhardness of 7900–10,520 MPa. In these metal-ceramic layers, a dispersed subgrain structure, a uniform distribution of nanoparticles, and a gradient-free level of dislocation density are observed. Such a structure prevents the formation of local concentrators of internal stresses, thereby increasing the level of dispersion and substructural strengthening of the metal-ceramic layers’ material. The formation of materials with a nanostructure increases their strength and crack resistance. The effectiveness of using aluminum, chromium, and silicon oxides as nanofillers in epoxy composite layers was demonstrated. The presence of structures near the surface of these nanofillers, which differ from the properties of the epoxy matrix in the coating, was established. Such zones, specifically the outer surface layers (OSL), significantly affect the properties of the epoxy composite. The results of industrial tests showed the high performance of the multilayer coating during antenna heating. Full article

In wet flue gas desulfurization and denitrification processes, nitrite accumulation inhibits denitrification efficiency and induces secondary pollution due to its acidic disproportionation. This study developed a Mn-modified ZSM-5 zeolite catalyst, achieving efficient resource conversion of nitrite in nitrogen-containing wastewater through an O₃ + Mn/ZSM-5 catalytic system. Mn/ZSM-5 catalysts with varying SiO₂/Al₂O₃ ratios (prepared by wet impregnation) were characterized by BET, XRD, and XPS. Experimental results demonstrated that Mn/ZSM-5 (SiO₂/Al₂O₃ = 400) exhibited a larger specific surface area, enhanced adsorption capacity, abundant surface Mn³⁺/Mn⁴⁺ species, hydroxyl oxygen species, and chemisorbed oxygen, leading to superior oxidation capability and catalytic activity. Under the optimized conditions of reaction temperature = 40 °C, initial pH = 4, Mn/ZSM-5 dosage = 1 g/L, and O₃ concentration = 100 ppm, the $\mathrm{N}{\mathrm{O}}_2^{-}$ oxidation efficiency reached 94.33%. Repeated tests confirmed that the Mn/ZSM-5 catalyst exhibited excellent stability and wide operational adaptability. The synergistic effect between Mn species and the zeolite support significantly improved ozone utilization efficiency. The O₃ + Mn/ZSM-5 system required less ozone while maintaining high oxidation efficiency, demonstrating better cost-effectiveness. Mechanism studies revealed that the conversion pathway of $\mathrm{N}{\mathrm{O}}_2^{-}$ followed a dual-path catalytic mechanism combining direct ozonation and free radical chain reactions. Practical spray tests confirmed that coupling the Mn/ZSM-5 system with ozone oxidation flue gas denitrification achieved over 95% removal of liquid-phase $\mathrm{N}{\mathrm{O}}_2^{-}$ byproducts without compromising the synergistic removal efficiency of NO_x/SO₂. This study provided an efficient catalytic solution for industrial wastewater treatment and the resource utilization of flue gas denitrification byproducts. Full article

Graphene-based textile pressure sensors are emerging as promising candidates for wearable sensing applications due to their high sensitivity, mechanical flexibility, and low energy consumption. This study investigates the design, fabrication, and electromechanical behaviour of graphene-coated nonwoven textile-based piezoresistive pressure sensors, focusing on the impact of different electrode materials and fabrication techniques. Three distinct sensor fabrication methods—drop casting, electrospinning, and electro-spraying—were employed to impregnate graphene onto nonwoven textile substrates, with silver-coated textile electrodes integrated to enhance conductivity. The fabricated sensors were characterised for their morphology (SEM), chemical composition (FTIR), and electromechanical response under cyclic compressive loading. The results indicate that the drop-cast sensors exhibited the lowest initial resistance (~0.15 kΩ) and highest sensitivity (10.5 kPa⁻¹) due to their higher graphene content and superior electrical connectivity. Electro-spun and electro-sprayed sensors demonstrated increased porosity and greater resistance fluctuations, highlighting the role of fabrication methods in sensor performance. Additionally, the silver-coated knitted electrodes provided the most stable electrical response, while spun-bonded and powder-bonded nonwoven electrodes exhibited higher hysteresis and resistance drift. These findings offer valuable insights into the optimisation of graphene-based textile pressure sensors for wearable health monitoring and smart textile applications, paving the way for scalable, low-power sensing solutions. Full article

Several Cu and Ni-based catalysts were synthetized over Ce-based supports, either pure or mixed with different amounts of alumina (1:2 and 1:3 mol/mol). Different metal loadings (10–40 wt%) and preparation methods (wet impregnation, co-precipitation, and flame-spray pyrolysis—FSP) were compared for the oxidative steam reforming of methanol. Characterization of the catalysts has been performed, e.g., through XRD, BET, XPS, TPR, SEM, and EDX analyses. All the catalysts have been tested in a bench-scale continuous setup. The hydrogen yield and methanol conversion obtained have been correlated with the operating conditions, metal content, crystallinity of the catalyst particles, total surface area, and with the interaction of the metal with the support. A Cu loading of 20% wt/wt was optimal, while the presence of alumina was not beneficial, decreasing catalyst activity at low temperatures compared with catalysts supported on pure CeO₂. Ni-based catalysts were a possible alternative, but the activity towards the methanation reaction at relatively high temperatures decreased inevitably the hydrogen yield. Durability and deactivation tests showed that the best-performing catalyst, 20% wt. Cu/CeO₂ prepared through coprecipitation was stable for a long period of time. Full methanol conversion was achieved at 280 °C, and the highest yield of H₂ was ca. 80% at 340 °C, higher than the literature data. Full article

Waterproofing sprays can cause acute respiratory symptoms after inhalation, including coughing and dyspnoea shortly after use. Here, we describe two cases where persons used the same brand of waterproofing spray product. In both cases the persons followed the instructions on the product and maximized the ventilation by opening windows and doors; however, they still became affected during the application of the product. Products with the same batch number as that used in one case were tested for their effect on respiration patterns of mice in whole-body plethysmographs and lung surfactant function inhibition in vitro. The product was used in spraying experiments to determine the particle size distribution of the aerosol, both using a can from one case and a can with an identical batch number. In addition, the aerosols in the mouse exposure chamber were measured. Aerosol data from a small-scale exposure chamber and data on the physical and temporal dimensions of the spraying during one case were used to estimate the deposited dose during the spraying events. All collected data point to the spraying of the waterproofing product being the reason that two people became ill, and that the inhibition of lung surfactant function was a key component of this illness. Full article

Degradation of ester-based polyurethane (PUR) foams results in extensive fragmentation, stickiness, and brittleness both at surfaces and in the bulk. Current methods to conserve museum objects comprising PUR foams include consolidation with solvent-based polymeric solutions. Besides the limitations of spray and brush application for deep consolidant penetration and the impracticality of immersing large-scale objects in solutions, these methods often require large amounts of toxic solvents that are harmful for both the user and environment. Carbon dioxide can be employed as a green solvent as it can be recovered, recycled, and reused without contributing to the greenhouse effect. Supercritical carbon dioxide (scCO₂)-assisted consolidation premises are that it may carry the consolidant deeper and deposit it consistently throughout the foam, whilst ensuring minimal interaction with the surface and avoiding material losses in severely degraded objects and the use of toxic solvents. The suitability of scCO₂ as a carrier is studied, and the results compared with spray application, a commonly used traditional method. Previous studies have shown that a mixture of alkoxysilanes has great potential for reinforcing the foam’s structure and hydrophobicity when applied by immersion and other impregnation techniques. In this study, scCO₂-assisted consolidation has proven to be an effective and green alternative to consolidation by spray, reducing hazardous solvent emissions. After treatment, no visual changes were detected, the samples became less sticky, and the foam flexibility improved significantly. Analytical techniques confirmed the presence of the consolidant in all tested samples, both on the top surface and in-depth layers, in contrast to foams treated by spray. Full article

Antimicrobial resistance (AMR) poses an emanating threat to humanity’s future. The effectiveness of commonly used antibiotics against microbial infections is declining at an alarming rate. As a result, morbidity and mortality rates are soaring, particularly among immunocompromised populations. Exploring alternative solutions, such as medicinal plants and iodine, shows promise in combating resistant pathogens. Such antimicrobials could effectively inhibit microbial proliferation through synergistic combinations. In our study, we prepared a formulation consisting of Aloe barbadensis Miller (AV), Thymol, iodine (I₂), and polyvinylpyrrolidone (PVP). Various analytical methods including SEM/EDS, UV-vis, Raman, FTIR, and XRD were carried out to verify the purity, composition, and morphology of AV-PVP-Thymol-I₂. We evaluated the inhibitory effects of this formulation against 10 selected reference strains using impregnated sterile discs, surgical sutures, gauze bandages, surgical face masks, and KN95 masks. The antimicrobial properties of AV-PVP-Thymol-I₂ were assessed through disc diffusion methods against 10 reference strains in comparison with two common antibiotics. The 25-month-old formulation exhibited slightly lower inhibitory zones, indicating changes in the sustained-iodine-release reservoir. Our findings confirm AV-PVP-Thymol-I₂ as a potent antifungal and antibacterial agent against the reference strains, demonstrating particularly strong inhibitory action on surgical sutures, cotton bandages, and face masks. These results enable the potential use of the formulation AV-PVP-Thymol-I₂ as a promising antimicrobial agent against wound infections and as a spray-on contact-killing agent. Full article

A Rift Valley fever (RVF) outbreak occurred in at least five regions of Madagascar in 2021. The aim of this study was to provide an overview of the richness, abundance, ecology, and trophic preferences of mosquitoes in the Mananjary district and to investigate the distribution of mosquitoes that were RT-PCR-positive for RVFV. Three localities were prospected from 26 April to 4 May 2021, using light traps, BG-Sentinel traps baited with an artificial human odor, Muirhead-Thomson pit traps, and indoor pyrethroid spray catches. A total of 2806 mosquitoes belonging to at least 26 species were collected. Of 512 monospecific pools of mosquitoes tested with real-time RT-PCR, RVFV was detected in 37 pools representing 10 mosquito species. The RVFV-positive species were as follows: Aedes albopictus, Ae. argenteopunctatus, Anopheles coustani, An. gambiae s.l., An. mascarensis, An. squamosus/cydippis, Culex antennatus, Cx. decens, Cx. Tritaeniorhynchus, and Uranotaenia spp. Of the 450 tested engorged females, 78.7% had taken a blood meal on humans, 92.9% on cattle, and 71.6% had taken mixed (human–cattle) blood meals. This investigation suggests the potential role of mosquitoes in RVFV transmission within this epizootic/epidemic context and that the human populations at the three study sites were highly exposed to mosquitoes. Therefore, the use of impregnated mosquito nets as an appropriate prevention method is recommended. Full article

This study utilizes desalted and denitrated treated aluminum dross (TAD) as a raw material, along with kaolin and 10 ppi (pores per inch) polyurethane foam as a template. The slurry is converted into an aluminum dross green body with a three-dimensional network structure using the impregnation method. A three-dimensional network aluminum dross ceramic framework (TAD_3D) is created at a sintering temperature of 1350 °C. The liquid 5A05 aluminum alloy at a temperature of 950 °C infiltrates into the voids of TAD_3D through pressureless infiltration, resulting in TAD_3D/5A05Al composite material with an interpenetrating phase composite (IPC) structure. The corrosion behavior of TAD_3D/5A05 composite material in sodium chloride solution was examined using the salt spray test (NSS) method. The study shows that the pores of the TAD3D framework, produced by sintering aluminum dross as raw material, are approximately 10 ppi. The bonding between TAD3D and 5A05Al interfaces is dense, with strong interfacial adhesion. The NSS corrosion time ranged from 24 h to 360 h, during which the composite material underwent pitting corrosion, crevice corrosion and self-healing processes. Results from Potentiodynamic Polarization (PDP) and Electrochemical Impedance Spectroscopy (EIS) indicate that, as corrosion progresses, the E_corr of TAD_3D/5A05Al decreases from −0.718 V to −0.786 V, and I_corr decreases from 0.398 μA·cm⁻² to 0.141 μA·cm⁻². A dense oxide film forms on the surface of the composite material, increasing the anodic Tafel slope and decreasing the cathodic Tafel slope, thus slowing down the rates of cathodic and anodic reactions. Factors such as lower interface corrosion resistance or a relatively weak passivation film at the interface do not significantly diminish the corrosion resistance of TAD_3D and 5A05Al. The corrosion resistance of the composite material initially decreases and then increases. Full article

Background: In Brazil, human visceral leishmaniasis (HVL) is caused by the protozoan parasite Leishmania infantum, primarily transmitted by the sand fly Lutzomyia longipalpis, with dogs acting as the main urban reservoir. This study aims to evaluate the effectiveness of 4% deltamethrin-impregnated dog collars (DMC) on HVL incidence. Methods: This is a community intervention study carried out from 2012 to 2015 in the municipalities of Araguaína, State of Tocantins, and Montes Claros, State of Minas Gerais, Brazil. Two areas in each were randomly allocated to either (1) culling seropositive dogs + residual insecticide spraying (control area—CA) or (2) culling seropositive dogs + residual insecticide spraying + DMC fitted to dogs every six months for two years (intervention area—IA). Cases of HVL (n = 1202) occurring from 2008 to 2020 were identified from the Brazilian Reportable Diseases Information System and georeferenced to the control and intervention areas. The HVL cases from 2008 to 2012 were considered as occurring in the “pre-intervention” period. Those cases from 2013 to 2016 and from 2017 to 2020 were regarded as occurring in the “intervention” and “post-intervention” periods, respectively. We used a mixed-effects Poisson regression model to estimate the effectiveness of the intervention, comparing the changes from the pre-intervention period to the intervention and post-intervention periods in the control and intervention areas. Results: In Araguaína, there was a statistically significant reduction in the incidence of HVL in both the control and intervention areas, comparing both the intervention and post-intervention periods with the pre-intervention period. The intervention with DMC was significantly associated with a reduction in HVL when comparing the intervention and pre-intervention periods, yielding an effectiveness estimate of the DMC of 27% (IC95% 1–46%, p = 0.045). No differences were observed when comparing the pre- and post-intervention periods (p = 0.827). In Montes Claros, cases reduced in both the control and intervention areas from the pre-intervention period to the intervention period (p = 0.913). In the post-intervention period, the incidence increased in the control area, while cases continued to decrease in the DMC area (p = 0.188). Conclusions: The use of DMC was associated with a reduction of 27% in the incidence of HVL during the period of DMC delivery, indicating that DMC is effective as an additional strategy for controlling visceral leishmaniasis in Brazil. However, no significant reduction associated with DMC was detected after the intervention period, suggesting that a control program based on the large-scale deployment of DMC might have to be maintained for more extended periods without interruption. Full article

Antimicrobial resistance (AMR) is a growing concern for the future of mankind. Common antibiotics fail in the treatment of microbial infections at an alarming rate. Morbidity and mortality rates increase, especially among immune-compromised populations. Medicinal plants and their essential oils, as well as iodine could be potential solutions against resistant pathogens. These natural antimicrobials abate microbial proliferation, especially in synergistic combinations. We performed a simple, one-pot synthesis to prepare our formulation with polyvinylpyrrolidone (PVP)-complexed iodine (I₂), Thymus Vulgaris L. (Thyme), and Aloe Barbadensis Miller (AV). SEM/EDS, UV-vis, Raman, FTIR, and XRD analyses verified the purity, composition, and morphology of AV-PVP-Thyme-I₂. We investigated the inhibitory action of the bio-formulation AV-PVP-Thyme-I₂ against 10 selected reference pathogens on impregnated sterile discs, surgical sutures, cotton gauze bandages, surgical face masks, and KN95 masks. The antimicrobial properties of AV-PVP-Thyme-I₂ were studied by disc diffusion methods and compared with those of the antibiotics gentamycin and nystatin. The results confirm AV-PVP-Thyme-I₂ as a strong antifungal and antibacterial agent against the majority of the tested microorganisms with excellent results on cotton bandages and face masks. After storing AV-PVP-Thyme-I₂ for 18 months, the inhibitory action was augmented compared to the fresh formulation. Consequently, we suggest AV-PVP-Thyme-I₂ as an antimicrobial agent against wound infections and a spray-on contact killing agent. Full article

Cobalt-doped alumina catalysts were prepared using different methods, either conventional wet impregnation (WI) and/or advanced spray impregnation (SI), and they were evaluated as novel oxidation catalysts for CO and MeOH oxidation. The spray impregnation technique was used with the aim of achieving the synthesis of core–shell catalytic nanostructures to secure the chemical/thermal stability of active sites on the catalyst carrier. The catalysts were further promoted with a low Pd content (0.5 wt.%) incorporated via either incipient wetness impregnation (DI) or spray impregnation. The results revealed the superior performance of the spray-impregnated catalysts (Co/γ-Al₂O₃-SI) for both reactions. The deposition of Co oxide on the outer surface of the alumina particle (SEM images) and the availability of the active Co phase resulted in the enhancement of the Co/γ-Al₂O₃ catalysts’ oxidation activity. Pd incorporation increased the catalysts’ reducibility (TPR-H₂) and improved the catalysts’ performance for both reactions. However, the Pd incorporation method affected the catalytic performance; with the SI method, the active phase of Co₃O₄ was probably covered with PdO and was not available for the oxidation reactions. On the contrary, the incorporation of Pd with the DI method resulted in a better dispersion of PdO all over the Co/Al catalyst surface, maintaining available Co active sites and a better Pd-Co interaction. MeOH desorption studies revealed the methanol oxidation mechanism: the Co/Al catalysts promoted the partial oxidation of MeOH to formaldehyde (HCHO) and dehydration to dimethyl ether (DME), while the Pd-based Co/Al catalysts enhanced the complete oxidation of methanol to CO₂ and H₂O. Full article

Non-stoichiometric CeO_2−y, especially in the form of nanocrystal aggregates, exhibits exceptional catalytic activity in redox reactions. It significantly improves the activity of transition metals and their oxides dispersed on/or in it, also acting as an oxygen buffer. Particularly, active oxygen species (O₂ⁿ⁻, O⁻) are generated at the M/CeO_2−y nanoparticle interface, as well as in the surface layer of their solid-state solutions M_xCe_1−xO_2−y. The crystal structure of CeO₂, ZrO₂ and (Ce, Zr)O₂ and its defects are discussed in connection with the resulting specific catalytic activity. All the methods (simple precipitation and co-precipitation from mother liquors, sol–gel methods, precipitation from nanoemulsions, hydrothermal and solvothermal techniques, combustion and flame spray pyrolysis, precipitation using molecular and solid-state matrices, 3D printing and mechanochemical methods) used for the synthesis of these nanomaterials are comprehensively reviewed, describing the rules of individual procedures and preparation details. Methods of deposition of metal catalysts and their oxides on CeO₂ nanoparticles, such as impregnation, washcoating and precipitation deposition, were also discussed. This review contains more than 160 references to representative papers wherein the reader can find further details on individual syntheses of effective ceria-based catalysts for redox reactions. Full article

For the first time, a study of the influence of the molecular weight of the thermoplastic partially crystalline polyimide R-BAPB on the thermophysical and mechanical properties of carbon plastics was presented. The molecular weight of polyimide was determined using the method of light scattering and the study of the intrinsic viscosity of polyamic acid solutions. To obtain CFRPs, the uniform distribution of polyimide powder on continuous carbon fibers via electrostatic spraying and further hot calendering and pressing were applied. The study of the structure of the obtained carbon plastics via scanning electron microscopy has shown that the growth of the molecular weight of polyimide prevents the impregnation of carbon fiber with the introduced polyimide. Moreover, an increase in the molecular weight of polyimide leads to a rise in glass transition and thermal decomposition temperatures up to 590 °C, while the degree of crystallinity of CFRP falls. Nonetheless, raising the molecular weight from 22,000 to 70,000 g/mol of a binder polymer improves the interlayer fracture toughness G_1C by more than five times. Full article

Visceral leishmaniasis (VL) was widely prevalent in Henan Province in the 1950s. Through active efforts by the government, there were no local cases reported from 1984 to 2015. In 2016, local VL cases reoccurred, and there was an increasing trend of VL cases in Henan Province. To provide a scientific control of VL, an investigation was conducted in Henan Province from 2016 to 2021. The data from VL cases were obtained from the Disease Surveillance Reporting System of the Chinese Center for Disease Control and Prevention. The rK39 immunochromatographic test (ICT) and PCR assay were performed among high-risk residents and all dogs in the patients’ village. ITS1 was amplified, sequenced, and subjected to phylogenetic analyses. A total of 47 VL cases were reported in Henan Province during 2016–2021. Of the cases, 35 were local, and they were distributed in Zhengzhou, Luoyang, and Anyang. The annual average incidence was 0.008/100,000, showing an upward trend year by year (χ² = 3.987, p = 0.046). Their ages ranged from 7 months to 71 years, with 44.68% (21/47) in the age group of 0–3 years and 46.81% (22/47) in the age group ≥15 years. The cases occurred throughout the year. The high-risk populations were infants and young children (age ≤3), accounting for 51.06% (24/47), followed by farmers at 36.17% (17/47). The ratio of males to females was 2.13:1. The positive rates of rK39 ICT and PCR were 0.35% (4/1130) and 0.21% (1/468) in the residents. The positive rates of rK39 ICT and PCR were 18.79% (440/2342) and 14.92% (139/929) in the dogs. The ITS1 amplification products in the patients and positive dogs were sequenced. The homology between the target sequence and Leishmania infantum was more than 98%. The phylogenetic analysis indicated that the patients and the positive dogs were infected by the same type of Leishmania, which was consistent with the strains in the hilly endemic areas in China. This paper showed that patients and domestic dogs were infected by the same type of L. infantum and that the positive rate in dogs was relatively high in Henan Province. Because the measures of patient treatment and culling of infected dogs were not effective in reducing VL incidence in Henan Province, it is urgent to develop new approaches for the control of VL, such as wearing insecticide-impregnated collars on dogs, treating the positive dogs, spraying insecticide for sandflies control, and improving residents’ self-protection awareness to prevent the further spread of VL in Henan Province. Full article