Mechanical Cleaning Methods Research Articles

Mechanical cleaning of graphene using in situ electron microscopy

Avoiding and removing surface contamination is a crucial task when handling specimens in any scientific experiment. This is especially true for two-dimensional materials such as graphene, which are extraordinarily affected by contamination due to their large surface area. While many efforts have been made to reduce and remove contamination from such surfaces, the issue is far from resolved. Here we report on an in situ mechanical cleaning method that enables the site-specific removal of contamination from both sides of two dimensional membranes down to atomic-scale cleanliness. Further, mechanisms of re-contamination are discussed, finding surface-diffusion to be the major factor for contamination in electron microscopy. Finally the targeted, electron-beam assisted synthesis of a nanocrystalline graphene layer by supplying a precursor molecule to cleaned areas is demonstrated.

An effective evidence-based cleaning method for the safe reuse of intermittent urinary catheters: In vitro testing.

To determine a safe bactericidal cleaning method that does not damage urethral catheters used for intermittent catheterization. In some countries, single-use catheters are the norm; in others, the reuse of catheters is common depending on health insurance, personal preference, or individual concerns about the environment. However, no recent study of cleaning methods has been published to provide evidence for the safe reuse of catheters. Using advanced microbiological methods, a laboratory study of eight cleaning methods was conducted. Sections of uncoated polyvinylchloride (PVC) catheters were exposed to bacterial uropathogens in physiologically correct artificial urine media then tested with a range of heat, chemical, and mechanical cleaning methods. Analysis of culturable and viable but nonculturable (VBNC) bacteria was done and direct microscopy was used. Descriptive statistics were used to compare values. Heat treatments, although effective, resulted in catheter surface breakdown and damage. Ultrasonic cleaning and vinegar showed evidence of VBNC populations indicating the methods were bacteriostatic. Detergent and water wash followed by immersion in a commercially available 0.6% sodium hypochlorite solution and 16.5% sodium chloride (diluted Milton) gave consistent bactericidal results and no visible catheter damage. Combined mechanical and chemical treatment of a detergent and water wash followed by immersion in diluted Milton (the "Milton Method") provided consistent and effective cleaning of uncoated PVC catheters, showing bactericidal action for all uropathogens tested after repeated exposure. If found safe in clinical testing, this method could increase the reuse of catheters, reduce plastic waste in the environment, reduce cost, and increase patient choice.

Removal of spoiling materials from solar panel surfaces by applying surface acoustic waves

Surface acoustic wave (SAW) technologies have been widely utilized for sensitive surface cleaning and particle steering applications in micro-electro-mechanical system (MEMS). This study investigates application of SAWs for cleaning of solar PV panel surfaces. Spoiling of photovoltaic (PV) solar panel surfaces is one of major problems that can reduce energy efficiency of PV solar energy systems in outdoor conditions. Rough mechanical cleaning methods can easily damage surface of panels and hence they can reduce efficient working life-span of panels. Therefore, sensitive and electronically controllable self-cleaning techniques are needed to keep PV panel surface cleaner. This study presents a theoretical analysis for detachment phenomenon of dust particles in interaction with SAWs. These analysis considers adhesion forces and effects of gravity in cleaning process and results reveal underlying mechanisms involving in particle detachment process. We derive sufficient conditions that are required for removal of a dust particle from inclined panel surfaces in case of SAW interactions. Experimental studies are conducted with spoiled PV solar panels, and cleaning effects of SAWs on solar panel surface are demonstrated.

Development of technology for water purification by filtration using vibration

Improving the quality of water treatment is accompanied by an increase in technology requirements. An important role in solving problems of technological ensuring the quality of treatment, among which a prominent place is occupied by filtration methods, biological, chemical and mechanical methods. Among the mentioned cleaning methods, mechanical cleaning methods and one of its varieties are widely used, a new model water purification by filtration using vibrationtechnology.

Removal of E. coli and Salmonella in pot ceramic filters operating at different filtration rates

The use of pot ceramic filters PCF to improve the domestic water quality supply has been recognized as an alternative in regions where there is unsecure water treatment or contamination of the treated water during transport and storage and an absence of safe drinking water. The aim of this study was to evaluate a model of PCF impregnated with colloidal silver under three filtration rates (1.0, 2.0 and 3.0 L/h) and three E. coli and Salmonella spp concentrations (104, 103 and 102 CFU/mL). The evaluation was made using spiked water having a turbidity of 29.9 ± 4.4 NTU and conductivity of 176 ± 31.7 μS/cm. The results showed a turbidity removal efficiency of 97% and average effluent of 0.9 NTU. The microbiological efficiency removal was of 2 Log Reduction Value (LRV) for E. coli and 1 LRV for Salmonella spp. There were not found significant statistical differences between the filtration rates and the removal efficiencies for turbidity E. coli and Salmonella spp. It was observed that the microbiological removal efficiency was affected by biofilm formation a phenomenon that was attributed to the presence of Salmonella spp. The combination of chemical and mechanical cleaning methods contributed to the elimination of the biofilm.

Effectiveness of a combination denture-cleaning method versus a mechanical method: comparison of denture cleanliness, patient satisfaction, and oral health-related quality of life

PurposeEffective denture plaque control is necessary in elderly individuals to prevent oral and systemic diseases. However, comparative studies of denture cleaning methods are limited, especially those investigating patient satisfaction. The present study aimed to evaluate effectiveness of a mechanical denture cleaning method versus a combination of mechanical and chemical methods in terms of denture cleanliness, patient satisfaction, and oral health-related quality of life (OHRQoL). MethodsThirty edentulous participants were allocated to one of two groups: mechanical or combination method. The mechanical method group was instructed to brush dentures after each meal for 2min using tap water and a denture brush, and to soak them in saline solution while sleeping. The combination method group was instructed to brush dentures the same way, but to soak them in denture cleansers while sleeping. Both groups cleaned their dentures according to the respective method for 3 weeks. Denture cleanliness, patient satisfaction, and OHRQoL were examined. ResultsThere were significant differences in adenosine triphosphate bioluminescence (p=0.00003), staining (p=0.003), and Candida albicans (C. albicans) abundance in upper complete dentures (p=0.002) between methods. There were no significant differences in oral mucosa C. albicans abundance, participant satisfaction, ease of cleaning, comfort, esthetics, or Oral Health Impact Profile for edentulous patients (Japanese version) scores between methods. ConclusionsA combination of mechanical and chemical denture cleaning methods was more effective at cleaning dentures than the mechanical method alone. Even if denture cleaning improves denture hygiene, it may not increase patient satisfaction or OHRQoL.

Evaluation of the effect of mechanical cleaning and manual cleaning in endotracheal tubes

Objective To observe the effect of mechanical cleaning and manual cleaning in endotracheal tubes. Methods The contaminated endotracheal tubes from 15 clinical departments in Qingdao Municipal Hospital (East Hospital) from March to November 2015 were selected and divided into 3 groups, using convenient sampling method. Manual cleaning method, manual + ultrasonic cleaning method and mechanical cleaning method with suction head on cleaning frame were used in these 3 groups respectively (group 1, n=713; group 2, n=1 187; group 3, n=1 109) . The cleaning effect of endotracheal tubes in these 3 groups were compared. Results Visual inspection and cleaning test rod inspection method suggest that the rate of return to wash when using mechanical cleaning method with suction head on cleaning frame were 1.80% and 3.84% respectively, which were significantly lower than the other two groups, with statistical differences (χ2=476.49, 40.67; P<0.01) . The rate of qualified drying was 100.00%, higher than the other two groups statistically (χ2=214.38, P<0.01) . Conclusions The mechanical cleaning method with suction head on cleaning frame is an effective cleaning method of endotracheal tubes. Key words: Cannula; Luminal instrument; Cleaning frame; Mechanical cleaning

An Unpublished Stela of Kharu and his wife Ty in the Egyptian Museum in Cairo (Temp. No. 11.1.25.7) لوحة غیر منشورة للمدعو خارو و زوجته تی فى المتحف المصری بالقاهرة (رقم مؤقت 11.1.25.7)

The rock art in the wadi Nasib are among the most important archaeological sites in South Sinai because The valley contained various inscriptions dating back to the prehistoric period until The new kingdom. It was discovered by the South Sinai Antiquities area. It includes many different incised and engraved rock inscriptions, where most of the Rock Art suffer from different phenomena of deterioration reaching disintegrating and cracking. Some of methods of examinations and analysis were done on the rock art case study, such as the Stereo-Microscope, polarized microscope PLM, Scanning Electron Microscope SEM-EDX, X-ray fluorescence XRF and X-ray diffraction XRD to know the mineral composition and its changes that occurred and explain the manifestations of the deterioration of the rock inscriptions in Wadi Nasib in South Sinai. The research proved that the rock inscriptions suffer from different phenomena of deterioration as fracture, cracking, scaling, peeling, fragmentation, honey comb, crystallization of salts on the surface and inside cracks, as well as weakness and fragile of sandstone being poor mineral composition, and decomposition of cementing material due to physio-chemical weathering processes, and because of falling The rock, which carries many inscriptions by mechanical weathering and Earthquakes, the man-made deterioration is the writings on the surface of the rock art with a sharp instrument or writing with the soot or chalk due to the poor archaeological awareness of the people, most phenomena of physio-chemical deterioration to the stone art in wadi Nasib is Direct and indirect dynamic and static deterioration factors being the site is a desert environment . Based on the results of scientific studies , The results of tests and analysis and Field survey, The restoration and conservation of rock art from the registration , documentation and the restoration have done by selection of suitable materials and methods appropriating to the nature of the damage of rock inscriptions in South Sinai, such as the use of mechanical cleaning methods with hand tools and chemical cleaning method where a mixture of acetone and Toluene ratio of 1: 2 was used to remove the clay soil sediments, mechanically and chemically extraction of salts are done using a poultice of distilled water then EDTA, and consolidating of rock art using The mixture of Nano Silica and Wacker H by Methods of spraying and brushing. The Research finds the need to raise the archaeological awareness of the people and specialists as one of the tools for preserving the rock art in Sinai , Rehabilitating the site and its developing for sustainable development, and placing it on the tourist map because it represents archaeological and historical importance in South Sinai. تتناول هذه الدراسة اللوحة الجنائزية للمدعو خارو و زوجته. اللوحة، التى توجد حاليا فى الطابق السفلي بالمتحف المصري بالقاهرة (رقم مؤقت 11.1.25.7)، تعود إلى عصر الرعامسة، بينما مصدرها الأصلي غير مؤکد. تشتمل اللوحة على ثلاثة أقسام، تصور صاحب اللوحة مع عائلته أمام أوزيريس، وإيزيس، وإلهة شجرة الجميز. وتهدف الدراسة إلى فهم أفضل للتقسيم الموضوعي لهذه اللوحة الجنائزية وتحديد صاحبها وعائلته.

Comparative study of mechanical and chemical methods for surface cleaning of a marine shell‐and‐tube heat exchanger

AbstractIn this article, experimental analysis is done on shell‐and‐tube heat exchanger of a marine vessel for removal of fouling using optimum surface‐cleaning techniques. The main objective is to compare the performance of the heat exchanger before and after maintenance. Two identical deteriorated systems of heat exchangers are taken and real‐time analysis is conducted. The log data are taken before and after undergoing maintenance for the two systems. Two different cleaning techniques are used, namely, chemical cleaning and mechanical cleaning. Detailed calculations are made for the shell‐and‐tube heat exchanger. From the obtained data, comparisons are made for different parameters on the tube side such as friction factor, heat transfer coefficient and pressure drop, as well as total heat transfer rate on the shell side. From the analysis and comparison, it was found that greater heat transfer takes place for the tubes cleaned using the chemical cleaning method than for tubes cleaned by the mechanical cleaning method. Pressure drop is found to be less for chemical cleaning method than mechanical cleaning method. This indicates that the fouling effect is reduced for tubes cleaned by the chemical cleaning method, and furthermore these tubes remain corrosion‐resistant for longer periods of time.

Reverse flexing as a physical/mechanical treatment to mitigate fouling of fine bubble diffusers.

Achieving energy neutrality has shifted focus towards aeration system optimization, due to the high energy consumption of aeration processes in modern advanced wastewater treatment plants. A study on fine bubble diffuser fouling and mitigation, quantified by dynamic wet pressure (DWP), oxygen transfer efficiency and alpha was carried out in Blue Plains, Washington, DC. Four polyurethane fine bubble diffusers were installed in a pilot reactor column fed with high rate activated sludge from a full scale system. A mechanical cleaning method, reverse flexing (RF), was used to treat two diffusers (RF1, RF2), while two diffusers were kept as a control (i.e., no reverse flexing). There was a 45% increase in DWP of the control diffuser after 17 months of operation, an indication of fouling. RF treated diffusers (RF1 and RF2) did not show significant increase in DWP, and in comparison to the control diffuser prevented about 35% increase in DWP. Hence, reverse flexing potentially saves blower energy, by reducing the pressure burden on the air blower which increases blower energy requirement. However, no significant impact of the RF treatment in preventing a decrease in alpha-fouling (αF) of the fine pore diffusers, over time in operation was observed.

Denture plaque microbiology in relation to removable denture hygiene methods

Introduction. Removable dentures, which constitute a reservoir of bacterial and fungal flora, can be an etiological factor responsible for generating local and systemic diseases. Plaque removal by applying mechanical and chemical methods is a basic principle of denture hygiene, it reduces the quantity of microorganisms and can play a role in the qualitative composition of bacterial biofilm. Aim of the study. To evaluate the impact of different denture hygiene methods on the composition of staphylococcal flora on the surface of denture base. Materials and methods. The study involved 62 patients of the Department of General and Transplantation Surgery and the Department of Prosthodontics. Each patient had a removable prosthesis. A thorough dental history with special emphasis put on denture hygiene methods was collected, swab from impression side of denture pate was sampled. Strains of the genus Staphylococcus were isolated and identified. Statistical analysis was conducted. Results. In the group of the examined patients, denture hygiene scheme based on toothbrush and toothpaste was most commonly used (53%). Bacterial strains of the genus Staphylococcus were found in 90% of subjects. The highest percentage of stains, including those with high pathogenicity (S.aureus, S.epidermidis, S.haemolyticus), were isolated in the subjects who used toothbrush and toothpaste and the lowest in those who regularly used mechanical and chemical denture cleaning methods. Conclusions. From a microbiological point of view, a combination of mechanical and chemical methods in regular denture hygiene, can help reducing the number of Staphylococcal strains. Patients, who receive an organ transplant should pay special attention to denture hygiene as microorganisms present on acrylic plate can pose a threat to their health and even life.

Effectiveness of chemical, mechanical and laser cleaning methods of sulphated black crusts developed on granite

A study of the cleaning effectiveness of sulphated black crust developed on granite is presented. The sulphated black crust, previously characterized, was subjected to a cleaning by 1) a mechanical procedure –Hydrogommage– based on micro-sandblasting, 2) chemical procedures based on the application of poultices made on different mixes of thickening agents and cleaners and 3) laser cleaning using a 355nm Nd:YVO4 nanosecond laser. Chemical, mineralogical and physical characterization of the cleaned surfaces were performed; the global effectiveness as well as the harmfulness were evaluated according to the level of black crust removal and the substrate damages. As result, none of the methods has been completely effective in removing the sulphated black crust and, also, all the methods produced undesirable effects on the stone. The crust nature, its degree of interaction with the stone and other factors related to the principle of the cleaning procedures were found as the main variables influencing the effectiveness of the cleaning procedures.

Investigation into the removal of graffiti on mineral supports: Comparison of nano-second Nd:YAG laser cleaning with traditional mechanical and chemical methods

This contribution discusses the analysis of polymeric paint layers and the removal of graffiti from historical buildings and sculptures. The main objective of the research is to compare the effectiveness of nano-second (ns) laser ablation with traditional cleaning procedures for the removal of painted graffiti from the surface of monuments. The vast number of various aerosol paints used for graffiti which contain different binders, solvents, and pigments does not allow the use of a single or universal cleaning method. In this study the efficacy of laser ablation was compared with chemical and mechanical cleaning methods. The laser system used for cleaning was a ns Nd:YAG, irradiating at 1064, 532, and 355 nm. Laser cleaning tests were performed on samples of limestone, sandstone, plaster, and brick covered with black, white, and red graffiti paints based on nitrocellulose, acrylic, and alkyd resins. Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX) were used to characterize paint binders. The morphology of treated surfaces was examined by optical microscopy and SEM. The results indicated the high efficiency of laser cleaning compared to traditional graffiti removal methods. A strong dependence of the efficacy of laser ablation on the paint composition and the porosity of the substrate was observed.

Cleaning the heat exchangers in biochemical systems

Methods of cleaning the heat exchangers in biochemical systems at OOO Mechel-Koks are considered. Literature data for the period 1956–2014 are analyzed. The basic cleaning methods used in 800KhPG-1.0-1.6-M1/25G-6-T-2-U heat exchangers are outlined: a mechanical cleaning method with disassembly of the heat exchanger; and a chemical method without disassembly. These two methods are tested in practice, and the best is identified. The method without disassembly may be characterized as waste-free. The results of cleaning are presented.

ABSTRACT 285

Background and aims: Effect of mechanical cleaning method with sterile urethral catheter on the formation of biofilm of endotracheal tubes. Aims: To investigate the intervention of mechanical cleaning method with sterile urethral catheter on the formation of biofilm of endotracheal tubes. Methods: With a prospective, randomized controlled trial, 45 children were randomized to urethral catheter cleaning group for 3 times a day(A group)?for 2 times a day (B group) and control group(C group). Bacterial studies and CLSM were performed to assess bacterial colonization and thickness of biofilm on the internal surface of the ETT. And the length of ICU stay?duration of mechanical ventilation and incidence of VAP among the three groups were compared. Results: The quantities of viable bacteria adhered on the ETT in A group was sharply lower compared with C group (P<0.05) and after 3 days of intubation, the differences between B and C group were also significant (P <0.05). (2) Observation by CLSM showed that the red bacteria were encased in mass of EPS which had green fluorescence and formed mature BF in C group; In A and B group, no biofilm or mature biofilm was seen. (3) Difference of the incidence of VAP among the three group was significant(P <0.01). No difference was observed among the three groups in ICU stay and duration of mechanical ventilation. Conclusions: The mechanical cleaning method with sterile urethral catheter 3 times a day could be more effective for preventing formation of ETT-BF and reducing the incidence of VAP and be safely used in clinical nursing.

The effect of an enzymatic bone processing method on short tandem repeat profiling of challenged bone specimens

Forensic analysis of DNA from bone can be important in investigating a variety of cases involving violent crimes and mass fatality cases. To remove the potential presence of co-mingled remains and to eliminate contaminants that interfere with forensic DNA analysis, the outer surface of the bone fragment must be cleaned. This study evaluated two methods for processing bone specimens prior to DNA isolation. Mechanical sanding and enzymatic trypsin methods were compared in this study. The effects of these methods on the yield of DNA isolated and the quality of DNA analysis were studied. It was revealed that comparable values of DNA yields between the two methods were observed. Additionally, to evaluate the capabilities of the cleaning effect of the bone processing methods, the presence of polymerase chain reaction inhibitors in the DNA extracts was monitored using the internal positive control. Similar Ct values of the internal positive control were observed as the DNA extracts of the trypsin method compared with that of the sanding method. The characterization of the effects of the trypsin treatment on the quality of DNA profiling was also carried out. To evaluate the integrity of the nuclear DNA isolated, the percentage of allele calls and the peak-height values of alleles of the short tandem repeat profiles were compared between the two methods. A paired-sample t-test revealed no significant difference between the two methods. Our data suggested that the trypsin method can be used as an alternative cleaning method to mechanical cleaning methods. This method can be used to process multiple samples simultaneously. This can be very important for achieving high-throughput DNA isolation through potential automation, which can be extremely valuable for situations such as the forensic DNA analysis of skeletal remains from mass fatality incidents.

Membrane Antifouling Methods and Alternatives: Ultrasound Approach

Membranes are widely used in separation processes. Various industries use membranes as part of their production processes. However, one of the main problems in membrane separation processes is fouling. The fouling mechanism is briefly reviewed in this paper. Fouling can be controlled before it happens. Alternatively, membranes can be cleaned after fouling occurs. Several control methods such as feed pre-treatment, material selection and membrane surface modification can be applied. Cleaning methods can be categorized into several techniques: chemical, mechanical, hydrodynamic, electrical and ultrasonic cleaning methods. This paper focuses on the ultrasonic cleaning method, which is an additional force that aids filtration. The mechanism of the ultrasonic wave that reduces fouling by cavitation and acoustic streaming is reviewed. The advantages and disadvantages of ultrasound irradiation as a cleaning method are also discussed in this paper. The apparatus design and factors that influence the effectiveness of ultrasound treatments, including frequency, power intensity, feed properties, membrane properties, cross-flow velocity, temperature and pressure, are analysed. Recently, ultrasound irradiation combined with other techniques has gained increasing attention. It has been discovered that a combination of other cleaning methods with ultrasound irradiation led to the removal of the fouling layers from the membrane surface.

Influence of Environmental Conditions and Application of Cleaning Methods against Biodeterioration of Marble Monuments

The aim of this paper is the study of the effect of environmental factors on the deterioration of marble monuments and the selection of a suitable and effective cleaning method. One of the main deterioration problems of the monuments is biodeterioration. It was obvious the presence of thick layers of biological patina, covering all almost surfaces of these. The growth of microorganisms, bacteria and plants is enhanced from the particular environmental conditions, that combine increased moisture, insolation and temperature, an area full of plants and trees and can cause extensive chemical and mechanical decay of the monuments. The growth of microorganisms, bacteria, plants and lichens was observed and determined. The influence of specific weathering agents and factors to the behavior of the materials was examined. The chemical composition of bulk precipitation and also the physicochemical characteristics of the surface and underground water were investigated. The environmental conditions and the growth of physical microorgamisms on the surface of the materials led to loss of the structural cohesion and the surface instability of the building materials. A series of various mechanical and chemical cleaning methods were tested in the laboratory containing the use of distilled water, microsandblast, organic solvents, absorbing clays, NH4HCO3 solution, biocides (desogen, hydrogen peroxide). In situ tests were carried out with satisfactory results in the monuments when a method of combination of hydrogen peroxide solutions, EDTA, NH4HCO3 solution and organic solvent was applied in various steps on the monument surface.

A bone sample cleaning method using trypsin for the isolation of DNA

Cleaning the surface of bone samples is a necessary step to remove contaminants prior to isolating DNA for forensic DNA analysis. In this study, a simple trypsin method for cleaning bone samples prior to DNA isolation was developed. Cleaning the surface of human bone samples was achieved by the application of trypsin solution. Light microscopy and scanning electron microscopy results indicated that trypsin treatment was effective in removing the outer surface of bone samples. The yield of DNA isolated from trypsin-treated bone samples was sufficient for subsequent short tandem repeat (STR) analysis. STR analysis revealed no adverse effect on the DNA profile after the trypsin treatment. The data suggest that this trypsin method can potentially be an alternative cleaning method to mechanical cleaning methods.

The Use of Laser Cleaning in the Conservation of Public Copper-Alloy Monuments in the UK

This paper presents two examples of the use of laser cleaning in the conservation of public copper-alloy monuments in the north-west of England during the past five years. Nd:YAG laser cleaning systems (emitting light at a wavelength of 1064 nm in pulses of 10 ns duration) have been used, in combination with chemical and mechanical cleaning methods, to remove unwanted paint layers and active corrosion products from the monuments to Lord Nelson and King Edward VII in Liverpool.