Abrasive Cleaning Research Articles

Doxycycline‐induced staining of permanent adult dentition

Doxycycline is the most effective antibiotic for managing brucellosis. Although it is relatively free from side effects, complications involving the skin, nails and teeth may rarely be encountered. Four patients with brucellosis developed yellow-brown discolouration of teeth following a 30-45 day course of doxycycline therapy during summer at a dose of 200mg/day. All four patients were diagnosed as having doxycycline-induced staining of the permanent dentition. In all cases, the staining completely resolved and the teeth recovered their original colour following abrasive dental cleaning. These observations indicate that the incidence of staining of the permanent dentition, as a complication of doxycycline, may be much higher than the literature indicates, especially if treatment is administered during summer months. Fortunately, this complication is reversible and does not require termination of doxycycline therapy. Complete resolution following abrasive cleaning may suggest that an extrinsic mechanism within the dental milieu may be involved in its pathogenesis. Strict avoidance of sunlight exposure during high-dose, long-term doxycycline therapy might prevent the development of this complication.

Technology Innovation for Determining Surface Roughness in Pipes

Technology Today Series articles are general, descriptive representations that summarize the state of the art in an area of technology by describing recent developments for readers who are not specialists in the topics discussed. Written by individuals recognized as experts in the area, these articles provide key references to more definitive work and present specific details only to illustrate the technology. Purpose: to inform the general readership of recent advances in various areas of petroleum engineering. Abstract Since 1995, several petroleum companies have actively sponsored research on how internal-surface wall-roughness texture affects the flow of fluids in oil-country tubular goods (OCTGs). The research goal focuses on the development and application of new technologies in combating the effects of pipe corrosion, establishing new piping materials and coatings, increasing the ease of fluid flow in pipes, and validating such improvements. A result of the research is a newly developed surface-roughness correlation for modern pipes. Introduction Currently, one area of focus is on achieving infrastructure-cost reductions in the transport of gas and oil through pipelines. Profilometer technology is a good example of one such application that is being adapted from the metal fabrication/manufacturing industry to measure the internal-surface roughness of piping. Internal-surface roughness impedes the dynamic transfer of fluids and is a major factor in the optimization of production tubing and pipeline utilization. Corrosion creates scale and pits along the walls of the piping, which in turn impedes flow and creates a loss of pipewall integrity. Other irregularities result from cutting tools, chatter, abrasive cleaning and preening operations, plating, anodizing, and chemical milling during manufacturing. The roughness of a solid surface is defined as any departure of the actual surface from an ideal datum level known as the nominal level. Surface profiling gauges the ups and downs of a surface, which the human eye cannot discern. The method results in a quick and easy way of calculating the pipe's friction factor. This method is a major step forward in production-tubing and pipeline design. The elimination of expensive and time-consuming flow-loop testing is the most obvious advantage of this technology.

Penetration of tritium (as tritiated water vapour) into low carbon steel and remediationusing abrasive cleaning

The UKAEA Winfrith site is in a phase of accelerated decommissioning and de-licensingwhich will generate significant volumes of metal wastes some of which may be suitable fordisposal as exempt wastes. If contamination is present, it is often confined withinthe surface layers of the metal. The UKAEA Winfrith site operates a shot-blastfacility (WACM) that removes paint and surface contamination from low carbonsteel enabling surface contaminated painted metal to be processed and thereforecertified as exempt. A study was conducted to determine whether tritium (astritiated water vapour) has penetrated into the metal to levels exceeding theRadioactive Substances Act (1993), Substances of Low Activity (SoLA) ExemptionOrder criteria, and whether processing via the WACM removes sufficient tritiumcontamination that the SoLA Exemption Order criteria can be met. The results ofsampling and analysis show that the tritium is mainly held in the paint or outer40 µm layer of the metal and that processing through the WACM removes these layers along withsufficient tritium to meet the SoLA Exemption Order criteria.

Abrasive blast cleaning and peening equipment

Abrasive blast cleaning and peening equipment

Evaluation of Surface Preparation Alternatives for Abrasive Blast Cleaning in Ship Repairing

Nowadays, the major argument against the use of dry abrasive blast cleaning focuses on its poor environmental compliance. The research work presented herein was the first of the kind ever to be conducted in Greece, and included the comparative examination of a number of alternative surface preparation methods and abrasives, on the basis of an integrated evaluation procedure. The results produced are in favor of the "best method for the job" approach, and advanced environmental protection has been taken into primary consideration.

Maintenance and repair issues for stone cleaned sandstone and granite building façades

Widespread stone cleaning of Scottish buildings began in the 1960s. In the earlier years, abrasive cleaning caused significant damage, especially to sandstone buildings, abrading the stone surface and blurring detail. Chemical cleaning systems avoided these problems, but could cause staining or bleaching; inevitable chemical retention within porous stone resulted in the formation of potentially damaging salts. Recent years have seen the development of considerably less damaging cleaning systems, however, the legacy of previous cleaning interventions remains with us. All too often stone cleaning has resulted in increased rates of decay on stone façades, with considerable long-term repair costs.

A topographical assessment and comparison of conservation cleaning treatments

The development of laser cleaning as a conservation treatment has imposed a need for the evaluation and assessment of other cleaning techniques. The use of more traditional methods like abrasive cleaning, steam cleaning and chemical cleaning has relied so far on visual assessment, unlike much of the research applied to laser cleaning. A conscientious use of these cleaning methods requires their assessment as well as the need for a comparison based on a common methodology. A topographical assessment of laser cleaning, abrasive cleaning, steam cleaning and chemical cleaning (using hydrofluoric acid, ammonium carbonate and EDTA) is presented. Topographical variations induced on marble, oolitic limestone and architectural terracotta surfaces are assessed by means of light interferometry, showing the potential of this non-contact and non-destructive technique for surface studies in conservation. The comparison between cleaning treatments is based upon key parameters associated with cleaning surfaces. The aesthetic impact of these treatments is verified by means of optical microscopy and quantified by colour measurement. Chemical analysis of the cleaned surface (EDS) is performed to investigate the removal of surface pollutants and the presence of residues. Finally, petrographical analysis was used to investigate the removal of pollutant layers and its effect on surface texture.

Adhesive Strength of Rubber Bonded to Al2O3 Surfaces: The Role of Chemistry and Morphology

Tensile pull tests were performed on polydimethylsiloxane (PDMS) rubber bonded to single-crystal and ceramic Al2O3 substrates prepared using several surface treatments. An accurate and reliable mechanical test method was developed using a frustro-conical geometry to eliminate the influence of tri-axial stress effects at the periphery. Properties of the sample surface were quantified prior to encapsulation using surface science techniques. Chemical cleaning of atomically-smooth sapphire resulted in a significantly larger joint strength (1 MPa) than attained from as-received substrates (0.448 MPa). The introduction of a significant amount of contamination (∼ 25 nm thick) from isopropyl alcohol (IPA) residue resulted in even weaker adhesion (0.241 MPa). Abrasive cleaning of sapphire using fine (∼ 100 micron) Al2O3 beads created more 0.5–1.0 micron topographic features and significantly higher joint strengths (1.103 MPa) than for similarly-prepared surfaces using coarse (∼ 350 micron) Al2O3 beads (0.621 MPa). The application of a titanate-modified silicone primer resulted in the greatest joint strength encountered (> 1.207 MPa), even when significant levels of surface contamination were present prior to priming. Adhesion to ceramic Al2O3 substrates was systematically stronger than to sapphire for as-received samples (0.965 MPa), abrasively-cleaned surfaces (1.034 MPa), and surfaces containing IPA residue (0.827 MPa) as a result of the rougher topography.

Origin of Metallic Particles Resembling Microcalcifications on Mammograms after Use of Abrasive Cautery-Tip Cleaning Pads during Breast Surgery: Experimental Demonstration

To determine if the act of cleaning a cautery tip with an abrasive pad dislodges radiopaque particles that can be transferred to breast tissue during surgery, thereby mimicking microcalcifications at mammography. Mock breast surgery was performed by cauterizing bovine liver or fresh, normal, human breast tissue. The cautery tip was rubbed against a cleaning pad five to 20 times in the manner used intraoperatively and was touched on separate breast tissue specimens two to six times. Specimen radiography was then performed. Thirty-six breast specimens were used in three experiments, including 28 used for the experimental conditions and eight control specimens. Particles collected from the cleaning pads resembled microcalcifications. After cauterization of liver, breast tissue, or both, in series, particles transferred from the cautery tip to breast tissue specimens could be identified on specimen radiographs. Transfer of particles after cautery of breast tissue occurred with increased numbers of rubs and specimen contacts. Radiopaque aluminum oxide particles from abrasive cautery-tip cleaning pads can be dislodged and transferred to breast tissue during surgery. Scrutiny of high-detail, spot-compression, magnification mammograms will help identify these particles. Simple measures to mitigate particle transfer during breast surgery can prevent this problem and obviate a potential second procedure to remove particles mistaken for microcalcifications.

Laser cleaning of an eighteenth‐century parchment document

Abstract Laser cleaning of a late eighteenth‐century parchment document has been carried out. A Q‐switched Nd:YAG laser emitting laser radiation at a wavelength of 1.06 μm in pulses of 10 ns duration was used to remove soiling from the surface of the document; results were compared with those obtained using more traditional methods: abrasive cleaning and wet cleaning. Thermochemical analysis (shrinkage temperature measurements) and chemical analysis (amino acid analysis) have been carried out on laser‐cleaned areas to assess any detrimental changes to the structure of the parchment resulting from exposure to laser radiation. The interaction of laser radiation with three ink types on the document is also discussed. The results of this work suggest that laser cleaning at 1064 nm offers an extremely sensitive alternative to traditional methods of cleaning parchment documents in a relatively stable condition.

The Importance of Substrate Surface Condition in Controlling the Porosity of Electroless Nickel Deposits

SummaryAn overview is presented of factors affecting the porosity of EN deposits and considers three aspects: (a) the type of ferrous material (e.g. ‘Pyrene’ steel panels, machined steel, cast iron), (b) the nature and degree of surface roughness (produced e.g. by abrasive papers, grit blasting or chemical cleaning) and (c) the type of chemical pretreatment applied to the steel. A range of different substrate types (grit blasted, ground, milled and cold rolled) have been electroless nickel plated to three different thicknesses and tested for porosity. The nature of the type of pretreatment and its effect on deposit porosity has also been investigated. Talysurf measurements have shown that the surface morphology does not change significantly with deposit thicknesses up to 24 μm.Data obtained from microscopy, profilometric, electrochemical and corrosion rate measurements are used to illustrate the importance of these factors in controlling the degree of porosity in the EN deposit and the rate of corrosion of the steel substrate. It has been shown that choice of an adequate cleaning cycle is critically important to obtain pore free deposits.

A Novel Method for Refurbishing Used Hot Section Gas Turbine Blades

During the normal operation of a land-based gas turbine, attack will occur of the gas-washed surfaces of the rotating stationary blades in the turbine hot section. This attack and its intensity can be variable depending on the blade’s position in the turbine hot section. This attack will progressively degrade these gas-washed surfaces even if these surfaces have been previously coated with a protective layer. During the service period of the turbine, it will be necessary to refurbish the blades from the hotter section of the turbine. One of the refurbishment steps will be to provide the blades with a suitable replacement coating to afford protection until the next service period. Conventional refurbishment techniques used to clean the blade surface rely on abrasive cleaning and / or chemical pickling. These processes may be capable of removing superficial oxidation and any residual coating but are not able consistently to remove the substrate material that has suffered from corrosive attack. It is important that this attacked substrate layer be removed completely, otherwise any residual corrosion products, particularly the presence of deeply penetrated sulfides in grain boundaries, could significantly reduce the life of any subsequent coating. The technique described in this paper essentially activates the surface layer of the substrate that is corroded, thus rendering it more easily removed by chemical and physical means. It is possible by this method to remove up to 400 μm of the substrate material and provided that all the corrosion products are contained within this zone, it is demonstrated how this produces a clean unattacked surface that is necessary for any subsequent welding, brazing, or recoating operation.

Munkebo units reduce costs at A.S.C.

Advanced Surface Coatings Ltd, one of the south's leading abrasive blast cleaning, metal spraying and surface coating contractors, has installed two Munkebo MB‐150E vacuum recovery abrasive recycling units at their Alresford, Hampshire works. The units are being used in conjunction with Clemco Contractor NC 2452 blast cleaning machines to provide an automatic abrasive blast cleaning and media recovery/cleaning facility.

A Comparative Study of Silver Cleaning Abrasives

The intent of this investigation was to identify a relatively safe and effective abrasive cleaning system for use on museum silver. This research, performed at the Getty Conservation Institute (Gel) and the Los Angeles County Museum of Art (LACMA), was coordinated with the actual cleaning, polishing, and lacquering of a large silver collection at the museum. Tarnished sterling silver samples were cleaned using 13 abrasives and 2 carrier fluids. The amount of silver removed, the relative amount of tarnish remaining, and the appearance of the silver surface after cleaning were assessed. Independent bench tests were performed by LACMA conservation staff to compare subjectively the results produced by the various abrasives, carrier fluids, and abrasive support cloths. It was found that calcium carbonate, gamma alumina, and chromium oxide suspended in deionized water containing a nonionic surfactant removed tarnish successfully and caused the least amount of damage to the silver. The mechanisms of polishing and factors to be considered in selection of museum silver cleaning systems are discussed.

A Comparative Study of Silver Cleaning Abrasives

The intent of this investigation was to identify a relatively safe and effective abrasive cleaning system for use on museum silver. This research, per- formed at the Getty Conservation Institute (GCI) and the Los Angeles County Museum of Art (LACMA), was coordinated with the actual cleaning, polishing, and lacquering of a large silver collection at the museum. Tarnished sterling silver samples were cleaned using 13 abrasives and 2 carrier fluids. The amount of silver removed, the relative amount of tarnish remaining, and the appearance of the silver surface after cleaning were assessed. Independent bench tests were per- formed by LACMA conservation staff to compare subjectively the results produced by the various abrasives, carrier fluids, and abrasive support cloths. It was found that calcium carbonate, gamma alumina, and chromium oxide suspended in deionized water containing a nonionic surfactant removed tarnish successfully and caused the least amount of damage to the silver. The mechanisms of polishing and factors to be considered in selection of museum silver cleaning systems are dis- cussed.

Analysis of indium nitride surface oxidation

InN is a III–V semiconductor with a wide band gap of 1.89 eV and mobility of 2700 cm2 V−1 s−1 (300 K) which has applications in optoelectronics. As with GaAs, surface oxidation and degradation after aging in air is a problem that must be taken into account during device fabrication. Of the possible techniques, x-ray photoelectron spectroscopy was used as it could detect nitrogen, while the x-ray beam did not preferentially sputter nitrogen as rapidly as other techniques. Various sample preparation techniques and sputter etching with xenon were used to avoid nitrogen depletion as well as to view initial chemisorption of oxygen onto InN surfaces. We found the surface oxidation of InN was clearly dependent on the aging and sample treatment history. The first stage of oxidation is the bonding of oxygen onto nitrogen to form an In–NO complex. After sputter etching or abrasive cleaning, the In–NO complex further oxidized to form an In–NO2 complex. The final oxidation state after aging was found to be dependent on the sample preparation conditions. Finally, the In(3d5/3) Auger parameter plots indicate that the indium is predominantly bonded to nitrogen regardless of the aging and sample treatment. These results correspond closely to studies on GaAs where during the oxidation process, oxygen chemisorbs onto the metalloid.

Contact lens surface changes after exposure to surfactant and abrasive cleaning procedures.

Proper lens maintenance is required if contact lens wear is to be successful. Poor compliance or inadequate cleaning may lead to contact lens failures and potentially damage to the eye. With phase contrast microscopy, we addressed the effect of cleaning systems on the physical integrity of a surface-modified lens--the Silcon contact lens. Several cleaners were evaluated for their ability to clean Silcon lenses with minimal damage to the lens surface. The data demonstrated that: all cleaning techniques alter the surface appearance; scratches develop more readily on lenses received with surface irregularities; wettability does not correlate with the extent of surface scratching; recommended cleaning procedures do not directly alter the wettability of the contact lens material; and phase contrast microscopy may be a useful addition to laboratory quality control.

Shotblasting for corrosion‐free surface preparation: a review of new equipment and processes

New wet blasting system Perhaps abrasive blast cleaning's most significant development of recent years has been wet blasting. It was initially used as a method of suppressing dust, but is now recognised as an important factor in surface preparation.

Comment

At a time when most industries are reporting a decline in activities, it is worth noting that the field of abrasive blast cleaning of steel fabrications has never been busier. Ten years ago, less than 50 per cent of such fabrications produced in the U.K. were blast‐cleaned: the majority were left to weather”, so removing mill scale, wire brushed and then primed and the rest left to chance. Today, nearly 100 per cent are now blast‐cleaned. The method has become accepted as the most suitable for preparing metal surfaces prior to the application of protective coatings and many organisations have put in a lot of work to lay down precise standards.

The Power Blast room system

A shotblast room can be very complex and expensive. It has to provide protection, ventilation, abrasive recovery, abrasive cleaning, dust removal and collection, and very good lighting.