On the emergence of antibacterial and antiviral copper cold spray coatings

In this literature review, the antipathogenic properties and contact-mediated antibacterial and antiviral performance of copper cold spray surfaces are assessed and compared with alternative antimicrobial materials that are able to kill and/or inactivate infectious agents via direct contact. Discussion is also provided concerning the suitability of copper cold spray material consolidations as biocidal and viricidal surfaces that retain long-term functionality as a preventative measure against fomite transmission of pathogenic agents and hospital-acquired infections from contaminated high-touch surfaces. Numerable alternative antimicrobial coatings and surfaces that do not rely upon the oligodynamic action of copper are detailed. Given the ongoing need for recognition of said alternative antimicrobial materials by authoritative agencies, such as the U.S. Environmental Protection Agency, the relevant literature on non-copper-based antipathogenic coatings and surfaces are then described. Furthermore, a wide-ranging take on antipathogenic copper cold spray coatings are provided and consideration is given to the distinctive grain-boundary mediated copper ion diffusion pathways found in optimizable, highly deformed, copper cold spray material consolidations that enable pathogen inactivation on surfaces from direct contact. To conclude this literature review, analysis of how copper cold spray coatings can be employed as a preventative measure against COVID-19 was also presented in light of on-going debates surrounding SARS-CoV-2’s non-primary, but non-negligible, secondary transmission pathway, and also presented in conjunction with the inevitability that future pathogens, which will be responsible for forthcoming global pandemics, may spread even more readily via fomite pathways too.

Understanding the Antipathogenic Performance of Nanostructured and Conventional Copper Cold Spray Material Consolidations and Coated Surfaces

The role of high strain rate and severe plastic deformation, microstructure, electrochemical behavior, surface chemistry and surface roughness were characterized for two copper cold spray material consolidations, which were produced from conventionally gas-atomized copper powder as well as spray-dried copper feedstock, during the course of this work. The motivation underpinning this work centers upon the development of a more robust understanding of the microstructural features and properties of the conventional copper and nanostructured copper coatings as they relate to antipathogenic contact killing and inactivation applications. Prior work has demonstrated greater antipathogenic efficacy with respect to the nanostructured coating versus the conventional coating. Thus, microstructural analysis was performed in order to establish differences between the two coatings that their respective pathogen kill rates could be attributed to. Results from advanced laser-induced projectile impact testing, X-ray diffraction, scanning electron microscopy, electron backscatter diffraction, scanning transmission microscopy, nanoindentation, energy-dispersive X-ray spectroscopy, nanoindentation, confocal microscopy, atomic force microscopy, linear polarization, X-ray photoelectron spectroscopy, electrochemical impedance spectroscopy and copper ion release assaying were performed during the course of this research.

Synthesis and Properties of a Reinforcing Dust-Cementing Material for Thin Spray-On Liners in Mine Roadways

The sprayed concrete in mine roadways suffers from a prolonged exposure to the harsh environment in the underground mine, leading to its detachment which may compromise its supporting strength. Besides, the dust-cementing effect of the conventional concrete is poor, providing very limited contribution to suppress the dust-laden airflow. As such, the present experiment uses sodium carboxymethyl cellulose as the base to produce a novel thin spray material through graft copolymerization based on acrylic acid and polyaluminum chloride. This new material can not only reinforce the surrounding rock of the roadway but also cement the dust in the airflow. Infrared spectroscopy, X-ray diffraction, thermal gravimetric analysis, and SEM are employed collectively to study the microscale reaction and structure of the product. A suite of experiment testing is carried out concerning the performance of the developed spray material, which reveals the supreme mechanical strength and desired properties of the hardened film developed from the spray material.

Modeling Aerially Applied Sprays: An Update to AGDISP Model Development

AGDISP (AGricultural DISPersal) models the release of aerially applied sprays with a Lagrangian-based droplet tracking algorithm initialized by user inputs (aircraft description, spray boom nozzle locations, drop size distribution, spray material properties, release height, and meteorology). The model offers an extensive set of output plots and toolbox options (deposition, spray block, stream, and multiple application assessments) to predict the downwind behavior of released sprays and assess their potential environmental impact. The model is used in risk analysis, operational planning, post-operation analysis, and training, particularly by the USDA Forest Service (FS) and its cooperators, including the U.S. Environmental Protection Agency (USEPA), the U.S. Fish and Wildlife Service, the U.S. Department of Defense, and various other state and private entities. This article updates the further development of the model since 2003, including the implementation of a quadratic droplet evaporation model and its behavior as Reynolds number approaches zero, a more accurate time step algorithm tied to droplet settling velocity, an optical canopy model, a Gaussian model for far-field extension (downwind to 20 km), an Eulerian model for tracking volatile active spray material, and the Tier 1 ground and orchard assessments previously developed by the Spray Drift Task Force (SDTF). Keywords: Aerial application, AGDISP, Model, Spray drift.

Fate of Preemergence Herbicide Applications Sprayed Through Containerized Hydrangea Canopies

Preemergent herbicides are applied to the soil or potted-substrate surface to prevent weed seedling establishment. Spraying through a canopy above the soil surface represents a challenge because of the filtering effect of the canopy on the spray stream and because of the additional distance created between the soil surface and nozzle. The objective of this work was to determine the effect spray quality, spray volume, and air delivery had on delivery of sprays to the substrate surface through a potted hydrangea canopy. Petri dishes and water sensitive paper were placed on the substrate surface of potted hydrangeas (H. paniculata ‘DVPpinky’) to collect spray material falling through the canopy. Eight targets were used for each plant and were place around the circumference of the pot in the four cardinal directions. Different sizes of TeeJet flat fan extended range (XR) and air induction (AI) nozzles were selected to provide 187 and 374 liters·ha−1 (20 and 40 gal·A−1) application rates with medium (XR) and very coarse (AI) droplet spectrums. A specially designed, five-port, air-assist delivery device was used to make air-assisted delivery applications using TeeJet XR8001 flat fan tips. Treatments were applied over the top of a 3 × 5 pot arrangement of potted plants at a speed of 4.0 km·h−1 (2.5 mph). No irrigation was applied either before or after treatment applications. Foliage sampled from the top of the hydrangea canopy had 8–10 times higher spray deposits than foliage from the middle elevation and the targets on the substrate surface. Surface coverage under the canopy ranged from 2–10% and average spot density ranged from 17–41% spots·cm−2 on water sensitive paper targets. Overall, the AI11003 used to make very coarse spray applications at 374 liters·ha−1 (40 gal·A−1) produced the highest mean spray deposits and coverage on the soil surface. The air-assist sprayer produced the highest deposits in the canopy but the lowest deposits and coverage on the substrate surface. On average, only about 5% of the spray actually reached the intended target (substrate surface) across all treatments and approximately 50–60% of the spray material was accounted for on the foliage. Larger droplet sizes and higher spray volumes will help ensure better delivery through the canopy.

On early Properties of High Performance Spray Material

This text used double fast cement, and fly ash, and high performance polymer and fiber for main material and plus agent for has high performance spray material of preparation and research, by distribution out of material has following advantages: condensation time fast, and short-term and late strength high, and dry shrink volume minimal, and stick poly sexual strong, and waterproof, and back bomb rate small, and seal performance very good, and has must of flexible, and using range wide.