The Experts below are selected from a list of 1134 Experts worldwide ranked by ideXlab platform
Matthew J. Vucko - One of the best experts on this subject based on the ideXlab platform.
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Innovative antifouling technologies: microtexture and metal
2014Co-Authors: Matthew J. VuckoAbstract:Fouling causes negative economic impacts to the major marine industries of shipping, aquaculture and geophysical exploration. Currently, the most widely used method to prevent the accumulation of fouling is copper-based biocidal antifouling paints. However, their deleterious impact on the marine environment and non-target organisms is driving the need to develop environmentally-sustainable antifouling technologies. Innovative antifouling technologies employing microtexture, photocatalysts and Cold Spray metal embedment are promising alternatives to current antifouling paints. This thesis investigates these alternative technologies to identify their efficacy across both niche and broad spectrum antifouling applications. In Chapter 2, a series of 18 textured (0.4–1,000 μm) and non-textured (0 μm) polydimethylsiloxane (PDMS) surfaces with round- and square-wave linear grating profiles were tested for their antifouling potential against the settlement of fouling organisms in the laboratory and in the field against the recruitment of a multi-species fouling community. In laboratory assays, Nitzschia closterium and Amphora sp. were deterred by all surface topographies regardless of texture periodicity. Settlement of Ulva sp. was lower on texture sizes less than propagule size, and settlement of Saccostrea glomerata and Bugula neritina was lower on texture sizes closest to, but less than, larval sizes. After the six month field trials, all textured surfaces lost their deterrent effect, however, the foul-release capabilities of textures were still present. High initial attachment was correlated with more fouling remaining after removal trials, indicating that fouling recruited in higher numbers to surfaces upon which they attached most strongly. In Chapter 3, the potential for a photocatalyst to enhance the antifouling properties of microtexture was examined. PDMS surfaces, textured with a square-wave linear grating profile (0, 20, 200, 300 and 600 μm), were embedded with a range of photocatalytic titanium dioxide (TiO₂) nanoparticle loadings (3.75, 7.5, 11.25 and 15 wt%). The resulting surfaces were used to test the combined efficacy of these technologies as antifouling materials in the laboratory and in the field against the common fouling bryozoan, B. neritina. Settlement of B. neritina was quantified in the laboratory under two intensities of ultraviolet light. The lowest settlement rates were observed on 20 μm surfaces. However, texture effects were not as critical to larval settlement as the presence of TiO₂. TiO₂, in conjunction with ultraviolet light, completely inhibited larval metamorphosis even at the lowest loading (3.75 wt%) and the lowest intensity of ultraviolet light (24 W m⁻²). Recruitment of B. neritina during field trials showed similar results to laboratory assays. The lowest recruitment occurred on 20 and 200 μm surfaces, with recruitment being significantly lower on all surfaces containing TiO₂. Therefore for B. neritina, although all TiO₂ loadings were effective, 3.75 wt% can be used as a minimum inhibitory concentration to deter larval settlement and the addition of a 20 μm texture further increases the deterrent effect. In Chapter 4, the use of Cold Spray Technology to give antifouling properties to thermoplastic polymers (polymers) by embedding metals known to prevent fouling was investigated. Two polymers, high-density polyethylene (HDPE) and nylon were metallised with copper powder using Cold Spray Technology. After 250 days in the field, copper-embedded HDPE and copper plate controls were completely free of hard foulers compared to copper-embedded nylon and polymer controls which were heavily fouled with both soft and hard fouling. The success of copper-embedded polymers is related to the interaction between the properties of the polymers (elastic modulus and hardness) and the Cold Spray process which affect particle embedment depth, and subsequently, the release of copper ions as determined by analytical techniques. This chapter demonstrates that embedding metal particles using Cold Spray equipment is an effective antifouling Technology for polymers, in particular those that are difficult to treat with standard copper-based biocide paints. Furthermore, efficacy is a function of the interaction between the Cold Spray metal and the polymer recipient. In Chapter 5, Cold Spray metal embedment was used to determine the effects of loading densities of metal particles on fouling. Antifouling efficacy under field conditions was quantified for low (22.1 ± 4.8 g m⁻²) and high (101.1 ± 10.8 g m⁻²) densities of copper particles embedded into polyurethane seismic streamer skins, which are used in geophysical exploration. Failure of each copper-embedded treatment was defined as settlement of hard foulers. Low-density streamers failed after 42 days while high-density streamers failed after 210 days. Most importantly, the high-density streamers were completely free of hard foulers including the barnacle Amphibalanus reticulatus during this time. In conclusion, Cold Spray metal embedment is an effective antifouling Technology for polyurethane seismic streamer skins, under intense fouling conditions. Higher copper particle densities enhance antifouling longevity and the effect of density provides a tool to extend efficacy and enhance antifouling performance for specific polymers. Finally, in Chapter 6, loading density gradients of metal particles were investigated. Particles of copper, bronze and zinc metal were embedded into a polymer using Cold Spray Technology to produce loading density gradients. The gradients were used to identify the species with the highest tolerance to the release of copper and zinc ions. The gradients also established the minimum effective release rates (MERRs) of copper and zinc ions needed to prevent the recruitment of fouling under field conditions. Watersipora sp. and Simplaria pseudomilitaris had the highest tolerance to the release of metal ions. Copper and bronze gradient tubes were similar in their MERRs of copper ions against Watersipora sp. (0.058 g m⁻² h⁻¹ and 0.054 g m⁻² h⁻¹, respectively) and against S. pseudomilitaris (0.030 g m⁻² h⁻¹ and 0.025 g m⁻² h⁻¹, respectively). Zinc was not an effective antifouling material with failure within two weeks. The Cold Spray gradients were effective in determining MERRs and these outcomes provide the basis for the development of Cold Spray surfaces with pre-determined life-spans using controlled MERRs. In summary, the research presented throughout this thesis describes innovative antifouling technologies that can be used as alternatives to current antifouling paints. In addition, this thesis identifies the efficacy of these technologies across niche and broad spectrum antifouling applications, while highlighting the importance of field-based trials. The incorporation of microtexture and a photocatalyst to already successful foul-release coatings, allows for further improvement of those materials. In addition, the use of Cold Spray Technology as an innovative method to give antifouling properties to thermoplastic polymers has been thoroughly investigated and provides a promising avenue for future research and commercialisation. In conclusion, this thesis provides a significant contribution to the relatively new field of environmentally-sustainable antifouling technologies and provides an innovative method to give antifouling properties to materials that previously, could not be protected against fouling.
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Cold Spray metal embedment: an innovative antifouling Technology
Biofouling, 2012Co-Authors: Matthew J. Vucko, P. C. King, Christina Carl, Andrew J Poole, Mahnaz Z. Jahedi, Rocky De NysAbstract:The study demonstrates that embedment of copper particles into thermoplastic polymers (polymers) using Cold Spray Technology is an effective deterrent against fouling organisms. Two polymers, high-density polyethylene (HDPE) and nylon were metallised with copper powder using Cold Spray Technology. After 250 days in the field, Cu-embedded HDPE and copper plate controls were completely free of hard foulers compared to Cu-embedded nylon and polymer controls which were heavily fouled with both soft and hard fouling. Antifouling (AF) success is related to the interaction between the properties of the polymers (elastic modulus and hardness) and the Cold Spray process which affect particle embedment depth, and subsequently, the release of copper ions as determined by analytical techniques. Embedding metal using Cold Spray equipment is shown to be an effective AF Technology for polymers, in particular those that are difficult to treat with standard AF coatings, with efficacy being a function of the interaction between the Cold Spray metal and the polymer recipient. © 2012 Copyright Taylor and Francis Group, LLC.
Rocky De Nys - One of the best experts on this subject based on the ideXlab platform.
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The release and uptake of metals from potential biofilm inhibition products during spiny lobster (Sagmariasus verreauxi, H. Milne Edwards 1851) culture
Aquaculture Research, 2015Co-Authors: Gg Smith, Stephen C. Battaglene, Andrew J Poole, Peter C. King, Quinn P. Fitzgibbon, Rocky De NysAbstract:Zinc (Zn) and copper (Cu) are strong inhibitors of bacterial biofilms in aqueous solutions, but are known toxins of crustaceans. A new metal application method; Cold-Sprayed metal embedment, known to modulate metal release, was tested for its applications in crustacean larval culture systems. Cold-Spray Technology allows metal particles to bond to plastics, while modulating metal ion release and biocide activity to the substrate boundary. In this study, Eastern spiny lobster (Sagmariasus verreauxi) larvae (phyllosoma) were cultured in the presence of Cold-Sprayed Zn and Cu metal surfaces. Metal loss was monitored gravimetrically on embedded surfaces, assessment of water ion concentrations and analysis of phyllosoma body content were undertaken. Phyllosoma moulting, deformity and mortality patterns were monitored. Cold-Sprayed Zn- and Cu-embedded surfaces were depleted with losses of 0.69% and 31.2% noted respectively. Culture water concentrations of these metals were elevated and accumulation by phyllosoma occurred. Water Zn concentrations of 18.5 μg L−1 were associated with chronic eyestalk moult deformities; the first report of Zn causing a non-lethal moult deformity in crustacean larvae. The Cu surface lost a third of its metal mass with a water concentration of 40 μg L−1 causing acute toxicity and localization of composite granules in the midgut gland. Cu associated mortality was noted by Day 2 of culture with a LD 50 experienced by Day 9. Future work on the use of bioactive metals in aquaculture systems will focus on a range of different metal alloys, and improved modulation of ion release mechanisms through increased particle embedment depth and separation.
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Cold Spray metal embedment: an innovative antifouling Technology
Biofouling, 2012Co-Authors: Matthew J. Vucko, P. C. King, Christina Carl, Andrew J Poole, Mahnaz Z. Jahedi, Rocky De NysAbstract:The study demonstrates that embedment of copper particles into thermoplastic polymers (polymers) using Cold Spray Technology is an effective deterrent against fouling organisms. Two polymers, high-density polyethylene (HDPE) and nylon were metallised with copper powder using Cold Spray Technology. After 250 days in the field, Cu-embedded HDPE and copper plate controls were completely free of hard foulers compared to Cu-embedded nylon and polymer controls which were heavily fouled with both soft and hard fouling. Antifouling (AF) success is related to the interaction between the properties of the polymers (elastic modulus and hardness) and the Cold Spray process which affect particle embedment depth, and subsequently, the release of copper ions as determined by analytical techniques. Embedding metal using Cold Spray equipment is shown to be an effective AF Technology for polymers, in particular those that are difficult to treat with standard AF coatings, with efficacy being a function of the interaction between the Cold Spray metal and the polymer recipient. © 2012 Copyright Taylor and Francis Group, LLC.
C Lee - One of the best experts on this subject based on the ideXlab platform.
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Neutron-Absorbing Coatings for Safe Storage of Fissile Materials with Enhanced Shielding & Criticality Safety NEUTRON-ABSORBING COATINGS FOR SAFE STORAGE OF FISSILE MATERIALS WITH ENHANCED SHIELDING & CRITICALITY SAFETY
2020Co-Authors: J. Farmer, J-s Choi, J C Farmer, C Lee, L Fischer, M Boussoufi, B Liu, H EgbertAbstract:Abstract Neutron-absorbing Fe-based amorphous-metal coatings have been developed that are more corrosion resistant than other criticality-control materials, including Al-B 4 C composites, borated stainless steels, and Ni-Cr-Mo-Gd alloys. The presence of relatively high concentration of boron in these coatings not only enhances its neutron-absorption capability, but also enables these coatings to exist in the amorphous state. Exceptional corrosion resistance has been achieved with these Fe-based amorphousmetal alloys through additions of chromium, molybdenum, and tungsten. The addition of rare earth elements such as yttrium has lowered the critical cooling rate of these materials, thereby rendering them more easily processed. Containers used for the storage of nuclear materials, and protected from corrosion through the application of amorphous metal coatings, would have greatly enhanced service lives, and would therefore provide greater long-term safety. Amorphous alloy powders have been successfully produced in multi-ton quantities with gas atomization, and applied to several half-scale spent fuel storage containers and criticality control structures with the high-velocity oxy-fuel (HVOF) thermal Spray process. Salt fog testing and neutron radiography of these prototypes indicates that such an approach is viable for the production of large-scale industrial-scale facilities and containers. The use of these durable neutron-absorbing materials to coat stainless steel containers and storage racks, as well as vaults, hot-cell facilities and glove boxes could substantially reduce the risk of criticality in the event of an accident. These materials are particularly attractive for shielding applications since they are fire proof. Additionally, layers of other Cold and thermal Sprayed materials that include carbon and/or carbides can be used in conjunction with the high-boron amorphous metal coatings for the purpose of moderation. For example, various carbides, including boron, tungsten, and chromium carbide, as well as graphite particles can be co-deposited with a metallic binder phase with either thermal Spray or Cold Spray Technology. These moderator layers would also be fire resistant. By coating the vessels and piping used for spent fuel reprocessing, including slab and pencil tanks, enhanced criticality safety and substantially better corrosion resistance can be achieved simultaneously. Since these alloys are Fe-based, any substitution of these for highperformance Ni-based alloys is expected to result in a cost savings. Ultimately, the cost of these materials should comparable to that of stainless steels
Andrew J Poole - One of the best experts on this subject based on the ideXlab platform.
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The release and uptake of metals from potential biofilm inhibition products during spiny lobster (Sagmariasus verreauxi, H. Milne Edwards 1851) culture
Aquaculture Research, 2015Co-Authors: Gg Smith, Stephen C. Battaglene, Andrew J Poole, Peter C. King, Quinn P. Fitzgibbon, Rocky De NysAbstract:Zinc (Zn) and copper (Cu) are strong inhibitors of bacterial biofilms in aqueous solutions, but are known toxins of crustaceans. A new metal application method; Cold-Sprayed metal embedment, known to modulate metal release, was tested for its applications in crustacean larval culture systems. Cold-Spray Technology allows metal particles to bond to plastics, while modulating metal ion release and biocide activity to the substrate boundary. In this study, Eastern spiny lobster (Sagmariasus verreauxi) larvae (phyllosoma) were cultured in the presence of Cold-Sprayed Zn and Cu metal surfaces. Metal loss was monitored gravimetrically on embedded surfaces, assessment of water ion concentrations and analysis of phyllosoma body content were undertaken. Phyllosoma moulting, deformity and mortality patterns were monitored. Cold-Sprayed Zn- and Cu-embedded surfaces were depleted with losses of 0.69% and 31.2% noted respectively. Culture water concentrations of these metals were elevated and accumulation by phyllosoma occurred. Water Zn concentrations of 18.5 μg L−1 were associated with chronic eyestalk moult deformities; the first report of Zn causing a non-lethal moult deformity in crustacean larvae. The Cu surface lost a third of its metal mass with a water concentration of 40 μg L−1 causing acute toxicity and localization of composite granules in the midgut gland. Cu associated mortality was noted by Day 2 of culture with a LD 50 experienced by Day 9. Future work on the use of bioactive metals in aquaculture systems will focus on a range of different metal alloys, and improved modulation of ion release mechanisms through increased particle embedment depth and separation.
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Towards integrated anti-microbial capabilities: Novel bio-fouling resistant membranes by high velocity embedment of silver particles
Journal of Membrane Science, 2015Co-Authors: Ludovic F Dumee, Maëlle Le Moing, Isabelle Güller, Peter D. Hodgson, Andrew J Poole, Peter C. King, Li He, Mikel Duke, Stephen Gray, Lingxue KongAbstract:Biofilm formation on membranes during water desalination operation and pre-treatments limits performance and causes premature membrane degradation. Here, we apply a novel surface modification technique to incorporate anti-microbial metal particles into the outer layer of four types of commercial polymeric membranes by Cold Spray. The particles are anchored on the membrane surface by partial embedment within the polymer matrix. Although clear differences in particle surface loadings and response to the Cold Spray were shown by SEM, the hybrid micro-filtration and ultra-filtration membranes were found to exhibit excellent anti-bacterial properties. Poly(sulfone) ultra-filtration membranes were used as for cross-flow filtration of Escherichia coli bacteria solutions to investigate the impact of the Cold Spray on the material׳s integrity. The membranes were characterized by SEM–EDS, FT-IR and TGA and challenged in filtration tests. No bacteria passed through the membrane and filtrate water quality was good, indicating the membranes remained intact. No intact bacteria were found on hybrid membranes, loaded with up to 15 wt% silver, indicating the treatment was lysing bacteria on contact. However, permeation of the hybrid membranes was found to be reduced compared to control non-modified poly(sulfone) membranes due to the presence of the particles across the membrane material. The implementation of Cold Spray Technology for the modification of commercial membrane products could lead to significant operational savings in the field of desalination and water pre-treatments.
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Cold Spray metal embedment: an innovative antifouling Technology
Biofouling, 2012Co-Authors: Matthew J. Vucko, P. C. King, Christina Carl, Andrew J Poole, Mahnaz Z. Jahedi, Rocky De NysAbstract:The study demonstrates that embedment of copper particles into thermoplastic polymers (polymers) using Cold Spray Technology is an effective deterrent against fouling organisms. Two polymers, high-density polyethylene (HDPE) and nylon were metallised with copper powder using Cold Spray Technology. After 250 days in the field, Cu-embedded HDPE and copper plate controls were completely free of hard foulers compared to Cu-embedded nylon and polymer controls which were heavily fouled with both soft and hard fouling. Antifouling (AF) success is related to the interaction between the properties of the polymers (elastic modulus and hardness) and the Cold Spray process which affect particle embedment depth, and subsequently, the release of copper ions as determined by analytical techniques. Embedding metal using Cold Spray equipment is shown to be an effective AF Technology for polymers, in particular those that are difficult to treat with standard AF coatings, with efficacy being a function of the interaction between the Cold Spray metal and the polymer recipient. © 2012 Copyright Taylor and Francis Group, LLC.
J. M. Guilemany - One of the best experts on this subject based on the ideXlab platform.
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Osteoblastic cell response on high-rough titanium coatings by Cold Spray
Journal of Materials Science: Materials in Medicine, 2018Co-Authors: A. M. Vilardell, N. Cinca, N. Garcia-giralt, S. Dosta, I. G. Cano, X. Nogués, J. M. GuilemanyAbstract:Highly rough and porous commercially pure titanium coatings have been directly produced for first time by the Cold Spray Technology, which is a promising Technology in front of the vacuum plasma Spray for oxygen sensitive materials. The wettability properties as well as the biocompatibility evaluation have been compared to a simply sand blasted Ti6Al4V alloy substrate. Surface topographies were analysed using confocal microscopy. Next, osteoblast morphology (Phalloidin staining), proliferation (MTS assay), and differentiation (alkaline phosphatase activity) were examined along 1, 7 and 14 days of cell culture on the different surfaces. Finally, mineralization by alizarin red staining was quantified at 28 days of cell culture. The contact angle values showed an increased hydrophilic behaviour on the as-Sprayed surface with a good correlation to the biological response. A higher cell viability, proliferation and differentiation were obtained for highly rough commercial pure titanium coatings in comparison with sand blasted substrates. Cell morphology was similar in all coatings tested; at 14 days both samples showed extended filopodia. A higher amount of calcium-rich deposits was detected on highly rough surfaces. In summary, in-vitro results showed an increase of biological properties when surface roughness increases.