Painted Metal Surfaces Research Articles

Graffiti coating eco-remover developed for sensitive surfaces by using an optimized high-pressure homogenization process

Nanostructured fluids (NSFs), such as water-in-oil (w/o) nanoemulsions (NEs), comprise one of the best examples of new, ecological products dedicated to removing various graffiti coatings (so-called eco-removers) from sensitive surfaces without causing damage underneath. These contemporary acceptable formulations are intended to be more efficient in removing undesirable graffiti coatings than traditional organic solvent-based preparations. In this paper, systematic studies were performed on the selective and controlled removal of paint and ink coatings from substrates that were sensitive to mechanical cleaning by using innovative graffiti coating removers in the form of “brush on, wipe off” detergents. The w/o NEs were fabricated by using a high-pressure homogenization process (HPH) from the following ingredients from sustainable sources of raw materials: esterified used cooking oils (Oil-PEG-8-ester), ethyl lactate (EL), water and saccharide-derived surfactants, such as alkyl polyglucosides (APGs), which have excellent wetting and detergent activities. The most efficient formulations achieved during the HPH process were determined by optimization through response surface methodology (RSM). The optimized w/o nanoemulsions were tested for the selective removal and wetting ability of graffiti coatings from selected sensitive surfaces, such as plastics, ceramics, or painted metal surfaces. Additionally, in studies of interaction with graffiti coatings, evaluating their surface properties (topography, wettability) on a real paint coating allowed for the assessment of the mechanism of graffiti paint removal by the proposed ecological remover. Using the "brush on, wipe off" cleaning procedure based on the developed w/o nanoemulsion systems has the potential to remove safely rough and heterogeneous graffiti coatings. Therefore, nanotechnological detergents are an outstanding environmentally friendly alternative to conventional graffiti coating removers.

Robot-assisted laser ablation for 3D surfaces. Application for paint removal with ultrashort pulse laser

In this work, a robot-assisted laser cleaning system is presented that allows the automatic processing of 3D objects with arbitrary geometry. The system is based on the integration of a femtosecond pulse laser with a 6-degree-of-freedom (6 DOF) robotic arm and a laser profilometer to capture the geometry of the workpiece. An automatic procedure is performed to generate cleaning paths over the geometry, which is finally targeted by a laser source by means of the prescribed robot motion; thus, both the working distance and the normal incidence of the laser beam are kept fixed for each point on the surface. The manipulator allows displacements and changes of orientation of the object to be processed following the programmed paths in a full 3D solution. The system was tested by performing the cleaning over different curved painted metal surfaces. Experimental results show the effectiveness of the proposed method that improves the efficiency of the automatic laser cleaning of 3D objects and further promotes its application to other ablation processes.

Strippable Polymeric Nanocomposites Comprising "Green" Chelates, for the Removal of Heavy Metals and Radionuclides.

The issue of heavy metal and radionuclide contamination is still causing a great deal of concern worldwide for environmental protection and industrial sites remediation. Various techniques have been developed for surface decontamination aiming for high decontamination factors (DF) and minimal environmental impact, but strippable polymeric nanocomposite coatings are some of the best candidates in this area. In this study, novel strippable coatings for heavy metal and radionuclides decontamination were developed based on the film-forming ability of polyvinyl alcohol, with the remarkable metal retention capacity of bentonite nanoclay, together with the chelating ability of sodium alginate and with “new-generation” “green” complexing agents: iminodisuccinic acid (IDS) and 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTC). These environmentally friendly water-based decontamination solutions are capable of generating strippable polymeric films with optimized mechanical and thermal properties while exhibiting high decontamination efficiency (DF ≈ 95–98% for heavy metals tested on glass surface and DF ≈ 91–97% for radionuclides 241Am, 90Sr-Y and 137Cs on metal, painted metal, plastic, and glass surfaces).

Rapid Synthesis of C-dots@PGV Nanocomposites Powders for Development of Latent Fingermarks

Abstract Novel fluorescent nanocomposites prepared by microwave irradiation and electrostatic adsorption have been formulated for developing latent fingermarks on various object surfaces. As-synthesized carbon dots@montmorillonite (C-dots@PGV) nanocomposites were characterized using UV–visible absorption spectroscopy, fluorescence spectroscopy, infrared spectroscopy, TEM/HRTEM, SEM and XRD. Due to its photoluminescence and stable chemical properties, C-dots@PGV nanocomposites powders with intense fluorescence produce sharp and clear development of latent fingermarks with good contrast and satisfactory ridge details. It is widely used for painted metal, glass, plastic and stainless steel surfaces, and the small, fine fluorescent nanocomposites demonstrate great advantages. Especially for multicolor surfaces, the fluorescent probe can help us to observe and photograph using UV light as excitation light source to eliminate background effects. After developing by facile powder technique, the prints emit strong violet-blue fluorescence under UV light (365 nm), at the same time, this nontoxic powder without any organic solvent and dyes can reduce harm to the operators.

Active FTIR-based stand-off spectroscopy using a femtosecond optical parametric oscillator.

We presented the first demonstration of stand-off Fourier transform infrared (FTIR) spectroscopy using a broadband mid-infrared optical parametric oscillator, with spectral coverage over 2700-3200 cm⁻¹. For vapor-phase water and nitromethane (NM), stand-off spectra was recorded using a concrete target at from 1-m to 2-m range and showed good agreement with reference spectra, and in NM a normalized detection sensitivity of 15 ppm·m·Hz(-1/2) was obtained. Spectra from 50-μL droplets of liquid thiodiglycol were detected at a stand-off distance of 2 m from aluminum, concrete and painted metal surfaces. Our results imply that OPO-based active FTIR stand-off spectroscopy is a promising new technique for the detection of industrial pollutants and the identification of chemical agents, explosives or other hazardous materials.

Discrete ordinate method for polarized light transport solution and subsurface BRDF computation

Interest in polarization properties of rendered materials is growing, but so far discussions on polarization have been restricted only to surface reflection, and the reflection due to subsurface scattering is assumed to be unpolarized. Findings from other fields (e.g. optics and atmospheric science) show that volumetric interaction of light can contribute to polarization. We thus investigated the polarized nature of the radiance field due to subsurface scattering as a function of the thickness of the material layer for various types of materials. Though our computations show negligible polarization for material layers of high thickness, light reflected on thin layered materials show significant degrees of polarization. Consequently, polarization cannot be ignored for subsurface component of reflection from painted surfaces (particularly painted metal surfaces) or from coated materials. Reflection from such surfaces is computed by solving for light transport in the different paint layers. In this paper we employ the vector radiative transfer equation (VRTE), which is the polarized version of the radiative transfer equation, inside the material. We use and detail a discrete ordinate based method to solve the VRTE and use the solution to compute the polarized radiance field at the surface of the material layer. We generate the polarimetric BRDF from the solutions of the VRTE for incident irradiance with different polarizations. We validate our VRTE solution against a benchmark and demonstrate our results through renderings using the computed BRDF.

A novel approach to estimating potential maximum heavy metal exposure to ship recycling yard workers in Alang, India

The 180 ship recycling yards located on Alang–Sosiya beach in the State of Gujarat on the west coast of India is the world's largest cluster engaged in dismantling. Yearly 350 ships have been dismantled (avg. 10,000 ton steel/ship) with the involvement of about 60,000 workers. Cutting and scrapping of plates or scraping of painted metal surfaces happens to be the commonly performed operation during ship breaking. The pollutants released from a typical plate-cutting operation can potentially either affect workers directly by contaminating the breathing zone (air pollution) or can potentially add pollution load into the intertidal zone and contaminate sediments when pollutants get emitted in the secondary working zone and gets subjected to tidal forces.There was a two-pronged purpose behind the mathematical modeling exercise performed in this study. First, to estimate the zone of influence up to which the effect of plume would extend. Second, to estimate the cumulative maximum concentration of heavy metals that can potentially occur in ambient atmosphere of a given yard. The cumulative maximum heavy metal concentration was predicted by the model to be between 113μg/Nm3 and 428μg/Nm3 (at 4m/s and 1m/s near-ground wind speeds, respectively). For example, centerline concentrations of lead (Pb) in the yard could be placed between 8 and 30μg/Nm3. These estimates are much higher than the Indian National Ambient Air Quality Standards (NAAQS) for Pb (0.5μg/Nm3).This research has already become the critical science and technology inputs for formulation of policies for eco-friendly dismantling of ships, formulation of ideal procedure and corresponding health, safety, and environment provisions. The insights obtained from this research are also being used in developing appropriate technologies for minimizing exposure to workers and minimizing possibilities of causing heavy metal pollution in the intertidal zone of ship recycling yards in India.

Carbocationic Polymerizations for Profit and Fun

AbstractThis presentation consists of two largely independent parts: The first åfor Profitα part concerns a bird's eye view of recently commercialized carbocationic processes and materials created by these processes in the author's laboratories whose marketing started during the past ∼5 years by various companies. These materials/processes include liquid telechelic polyisobutylene (PIB) for architectural sealants, poly(styrene‐b‐isobutylene‐b‐styrene) (PSt‐b‐PIB‐b‐PSt) triblocks for thermoplastic elastomers, PIB/PSt‐based blocks for coating of medical devices, and PIB‐based microemulsions for surface protection of painted metal surfaces. It is concluded that in order to enhance and solidify research in polymer synthesis it would behoove the scientific community to pay increased attention to intellectual property protection. Appropriately managed patenting and publishing activities are self‐reinforcing and may be quite profitable.The second “for Fun” part concerns a brief review of the design, synthesis and characterization of two novel fully aliphatic star‐block copolymers: ∅︁(PIB‐b‐PNBD)3 and ∅︁(PNBD‐b‐PIB)3 (where PNBD = polynorbornadiene). The constituent moieties of these star‐blocks are identical except their block sequences are reversed. Motivation for the synthesis of ∅︁(PIB‐b‐PNBD)3, consisting of a low Tg (∼‐73°C) PIB inner‐corona attached to a high Tg (∼320°C) PNBD outer corona, was the expectation that this star‐block would exhibit thermoplastic elastomer characteristics, and that it could be used in applications where similar polyaromatic‐based TPEs cannot be employed (e.g., magnetic signal storage). The other star‐block, ∅︁(PNBD‐b‐PIB)3, comprises the same building blocks with the PIB and PNBD sequences reversed. We found that the secondary chlorine at the PNBD chain end, in conjunction with TiCl4, is able to initiate the polymerization of isobutylene. Details of the carbocationic polymerization of NBD, together with the microstructure of PNBD, will be discussed.

Discrimination by EIS of degradation mechanisms in lap joints of coated metal sheet

The information derived from inspedance diagrams obtained by using electrochemical sensors specifically designed for lap joints testing of coated metallic sheets is analyzed. The electrochemical sensors were made by means of steel or zinc sheets, uncontaminated or contaminated with variable amounts of sodium chloride, and overcoated with organic coatings. Such sensors show the effect of the nature of the metallic substrate, the underfilm saline contamination, and the relative humidity of the environment outside the lap joint. The results show that the information obtained from electrochemical impedance spectroscopy (EIS) on the behavior within the lap joints can be assessed by the criteria traditionally used for plain painted metal surfaces. By modeling the data, it is possible to discriminate between effects due to the organic coating and to the corrosion reaction at the metal-coating interface.

Nettoyage et stabilisation de surfaces métalliques peintes: application à la restauration d'une voiture autochenille

Examination of the painted metal parts of a Citroën catelpillar car known as ‘Le Croissant d'Argent’, which took part in the Sahara Crossing of 1922–23, revealed that despite widespread corrosion the original paintwork had survived. A procedure was devised to clean and stabilize the painted metal surfaces, using pads soaked in a complexing solution of the tetrasodium salt of edta to dissolve surface corrosion products, and stabilizing oxidized iron alloys with an alcoholic acid mixture. This method is offered as a useful alternative for those responsible for automobile collections when minimal intervention is judged sufficient. The tests carried out to develop the treatments are also described.

Colonization by Cladosporium spp. of painted metal surfaces associated with heating and air conditioning systems.

Cladosporium cladosporioides and C. hebarum colonized painted metal surfaces of covering panels and register vents of heating, air conditioning and ventilation systems. Hyphae penetrated the paint film and developed characteristic conidiophores and conidia. The colonies were tightly appressed to the metal surface and conidia were not readily detectable via standard air sampling procedures.

Effectiveness of Three Residual Insecticide Formulations To Control Red Flour Beetles (Coleoptera: Tenebrionidae) On Painted and Unpainted Steel2

Three insecticides were tested for efficacy against adult red flour beetles on painted and unpainted steel plates. Microencapsulated formulations of chlorpyrifos and diazinon provided 100% control for 47 weeks on both painted and unpainted surfaces. A lacquer-based formulation of chlorpyrifos was not as effective and could have been affected by paint. These findings have importance in the control of stored product insect pests on painted metal surfaces, including the decks of naval vessels.