Mechanical Scrubbing Research Articles

ВЫБОР ТЕХНОЛОГИИ ПОВЫШЕНИЯ ГИДРОФОБНОСТИ И ИЗВЛЕКАЕМОСТИ АЛМАЗОВ ТРУБКИ "БОТУОБИНСКАЯ"

A promising direction for solving the problem of producing small diamonds is to expand the range of enriched classes and reduce diamond losses through the use of modern technologies. The article presents the results of research on the causes of reduced hydrophobicity of Botuobinskaya tube diamonds and the choice of parameters for preparing the feedstock for the processes of sticky and foam separation, ensuring the restoration of surface properties and extraction of hydrophilized diamonds into concentrate. Studies have shown that the mineral coatings on the surface of diamonds are fragments of primary or modified kimberlites, as well as slurries and films, firmly connected to the surface of diamond crystals. Diamonds from hypergenically altered kimberlites are characterized by the predominance of carbonate and aluminosilicate minerals. It has been shown by the method of unrestricted flotation of diamond-kimberlite samples that the use of mechanical scrubbing is effective enough to remove slurry coatings, but does not provide complete removal of car bonate-aluminosilicate microbreccias firmly bound to the surface of diamonds. As a result of the conducted research, it is shown that for a more complete recovery of small diamonds from kimberlites enriched at the Nyurbinsky GOK, it is advisable to use the processes of mechanical stripping and thermal cleaning of diamonds from hydrophilizing coatings to restore their hydrophobicity. It is shown that the use of a combination of these methods provides an increase in diamond recovery during sticky separation by 14.1 % and during foam separation by 20.4 %. The level of recovery of hydrophilic diamonds (more than 82 %) achieved using foam separation technology allows us to recommend this process for use in improving the technology of enrichment of small classes of diamonds.

Electrochemistry of copper post-CMP cleaning examined in combination with brush-scrubbing in a malonic acid solution

Post-CMP cleaning (PCMPC) is used in the fabrication of integrated circuits to remove unwanted residues of chemical mechanical planarization (CMP) from wafer surfaces. PCMPC combines (electro)chemical surface reactions in a cleaning solution with mechanical scrubbing by a brush. Using tribo-electrochemical protocols, the present work simultaneously probes the (electro)chemical and mechanical functions of PCMPC and determines the corresponding cleaning efficiency. Employing malonic acid as a cost effective, environmentally compatible cleaning solution for copper, it is demonstrated how this electroanalytical approach can facilitate the tasks of developing and evaluating effective PCMPC solutions. The results indicate that malonic acid in a pH neutral environment removes Cu-oxides and their co-adsorbed organic residues of CMP. A detailed electrochemical procedure is illustrated for quantifying the residue removal efficiency of PCMPC, and the role of brush scrubbing in the overall cleaning process is identified.

Dissimilar surface treated recycled coarse aggregate in concrete

The surface zone of the recycled aggregate plays a significant role in the strength and durability of concrete. In this research, various concrete series incorporating natural coarse aggregate [NCA], untreated recycled coarse aggregate RCA(UN), mechanical scrubbing treated coarse aggregate RCA(MS), sulfuric acid treated coarse aggregate RCA(H2SO4) and hydrochloric acid treated aggregate RCA(HCl) were investigated. Manufactured sand was used as an alternative to natural river sand in five series of concrete with 100% replacement ratio. The mechanical properties: compressive, split tensile, and flexural strength, respectively, were determined at the age of 28 and 56 days. Durability properties: water absorption, drying, sulfuric acid, sodium sulphate and sorptivity test were determined at the age of 28, 56 and 90 days and the results were compared to reference concrete. According to the results, RCA(UN) was found to marginally decreased the concrete performance, and the above mentioned treated aggregate shows a significant improvement in overall performance compared to RCA(UN), especially RCA(MS), which enhances the concrete more significantly than other methods. Moreover, the scanning electron microscope results also emphasize the enhanced microstructure of treated recycled aggregate in concrete. The photographic view of the cross sections of the samples shows a superior interfacial transition zone in all kinds of treated aggregate concrete than in untreated recycled aggregate concrete.

Effects of Mechanical Stirring and Ultrasound Treatment on the Separation of Graphite Electrode Materials from Copper Foils of Spent LIBs: A Comparative Study

In this paper, mechanical stirring and ultrasonic treatment are used to separate graphite electrode materials from copper foils in recycling spent lithium-ion batteries (LIBs). Firstly, the effects of ultrasonic power (60–180 W), ultrasonic time (1–8 min), stirring speed (420–2000 rpm), and stirring time (1–8 min) on the abscission rate of active material on copper foil were studied. It was found that the peeling-off ratio of electrode material under ultrasonic treatment was 91.34% compared with stirring treatment (84.22%). The removal of electrode material from copper foil during stirring was mainly through mechanical scrubbing. As a comparison, the generation of the microjets induced by ultrasound, the local high-temperature and high-pressure environment, and the free radicals during ultrasonic treatment are the key factors to further improve electrode material removal efficiency. An integrated ultrasound-mechanical stirrer technique can achieve a high-efficient separation performance (approximately 100% peeling-off ratio) of anode electrode materials from copper foils. The effects of mechanical stirring speed, temperature, and treatment time on the peeling-off ratios of the ultrasound-mechanical stirrer-assisted system were investigated. Finally, the results of XRF (X-ray fluorescence spectrometer), XRD (X-ray diffraction), and SEM-EDS (scanning electron microscopy coupled with energy dispersive X-ray spectroscopy) showed that the as-separated graphite electrode material had high purity and contained almost no copper foil impurities. Numerical simulation analyses briefly showed that the difference between pressure and ultrasonic temperature changes in the boundary between different anode layers (graphite on copper foil in aqueous solution) was the main effective factor in the considerable separation of graphite from copper anode foil under ultrasonic-assisted delamination.

Augmentation of dissimilar techniques for enhancing the concrete properties with recycled coarse aggregate and manufactured sand

In this present study, the demolition of building waste is used as an RCA in concrete. The various techniques like mechanical and chemical treatments are presented to recover the properties of RCA. Six dissimilar concrete mixtures were prepared using virgin coarse aggregate, RCA; aggregate obtained after treatment of Mechanical scrubbing (MS), Sulphuric acid (H2SO4) and Hydrochloric acid (HCl). The compressive strength of treated aggregate was enhanced by 7.78–25.79% than untreated recycled aggregate concrete. Split tensile strength has been enhanced by 5.22–18.80% higher than the untreated aggregate. The flexural strength of various treated RAC was improved by 4.91–25.24% at 28 days more than untreated recycled aggregate concrete. Alkalinity value of concrete is made with all types of coarse aggregates, the assessment of pH lies between 11.9 to 12.24 and it is pretty good. In drying test, the values are improved by 6.07–28.88% at 28 days than untreated coarse aggregates concrete. In water absorption test; the treated aggregate improved their results by 4.84–31.06% than untreated aggregate concrete. The investigation shows better results from various treated RCA in concrete. Especially, mechanical scrubbing (MS) treatment recovered higher than other techniques. But the results do not exceed the conventional concrete.

Standard Sand Specifications Development by Mechanical Attrition Scrubbing to Make it Convenient for the Cement Industry

This study was carried out to determine the possibility of improving the properties of the sand from Kasser Mohaiwir area in Al-Anbar Governorate to obtain sand specifications conforming to the standard sand specification (not exceeding 0.25% loss in acid). This study showed the possibility of obtaining standard sand with loss in hydrochloric acid up to 0.175 and recovery rate not exceeding 80% using mechanical methods without resorting to the use of acid methods currently in production.

Reclamation of Clay–Resin Mixed Waste Sand by a Hot Waste Alkali Liquor Soaking Assisted with Scrubbing Method

The reclamation of clay–resin mixed waste sand (CRMWS) reused over multiple cycles is difficult, while the commonly used thermal–mechanical reclamation process has some major drawbacks with regard to high acid consumption and low rebonding efficiency in the reclaimed sand. In this paper, a hot waste alkali liquor soaking assisted with scrubbing (HWALSS) reclamation method was proposed to reclaim CRMWS as new sand additional for the green sand molding line, as compared to the thermal–mechanical reclamation method and water scrubbing reclamation method. The properties of the reclaimed sand were investigated, and the reclamation mechanism was also discussed. The experimental results indicate that the reclamation method of HWALSS is feasible. The compressive strength (σ24h) of HWALSS reclaimed sand bonded by sodium silicate binder is 8.17 times and 2.71 times more than that of the thermal–mechanical reclaimed sand and the water scrubbing reclaimed sand, respectively. Morphological analysis reveals that the surface of HWALSS reclaimed sand is both smooth and clean, and the quantity and area of the bonding bridges of the sodium silicate bonded sand are found to be large compared to those of the thermal–mechanical and water scrubbing reclaimed sand, which are the main reasons for the improvement of the compressive strength.

Fast preparation and recycling method for colloidal probe cantilevers in hydrophobic mapping applications

Probe contamination of atomic force microscope (AFM) tips with colloidal probes is limiting the lifetime of the probe and the reproducibility in force interaction measurements, rendering cantilevers useless. Earlier proposed cleaning methods like mechanical scrubbing, UV, plasma and solvent cleaning procedures have limitations especially for inorganic particulate contaminations. In this paper we demonstrate a fast procedure to recycle contaminated colloidal probe cantilevers and reequip them with pristine colloids without affecting the mechanical and structural properties of the cantilever. The proposed procedure reduces the total time for probe preparation and allows extended experimental test work with singular cantilevers reducing the deviations by cantilever calibration.•fast preparation•recyclable cantilevers

Complete Eradication of Biofilm From Orthopedic Materials

BackgroundInterest exists in finding alternatives to current management strategies in periprosthetic joint infections, which typically include a 2-stage revision with placement of an antibiotic spacer and delayed placement of a new implant. We studied the efficacy of autoclaving, ultrasonication, and mechanical scrubbing for sterilization and biofilm eradication on infected cobalt-chrome discs. MethodsStrains of Staphylococcus aureus MRSA252 or Staphylococcus epidermidis RP62A were grown on the discs. For each strain, discs were divided into 5 groups (5 discs each) and exposed to several sterilization and biofilm eradication treatments: (1) autoclave, (2) autoclave + sonication, (3) autoclave + saline scrub, (4) autoclave + 4% chlorhexidine (CHC) scrub, and (5) autoclave + sonication + CHC scrub. Sterilization and biofilm eradication were quantified with crystal violet assays and scanning electron microscopy. ResultsRelative to nontreated controls, autoclaving alone reduced biofilm load by 33.9% and 54.7% for MRSA252 and RP62A strains, respectively. Biofilm removal was maximized with the combined treatment of autoclaving and CHC scrub for MRSA252 (100%) and RP62A (99.5%). The addition of sonication between autoclaving and CHC scrubbing resulted in no statistically significant improvement in biofilm removal. High-resolution scanning electron microscopy revealed no cells or biofilm for this combined treatment. ConclusionUsing 2 commonly encountered bacterial strains in periprosthetic joint infection, infected cobalt-chrome discs were sterilized and eradicated of residual biofilm with a combination of autoclaving and CHC scrubbing.

The use of alunitic kaolin in ceramic tile production

In this research, a beneficiation process including mechanical scrubbing, screening and milling was applied to the alunitic kaolins of the Balikesir-Sindirgi region of Turkey to remove alunite and the other impurities, after size reduction. Chemical and mineralogical analysis of the size groups was made to determine the changes with the composition for SiO2, SO3 and Fe2O3. Afterwards, the use of concentrated kaolins in ceramic tile production was investigated. For this purpose, three different recipes were prepared in order to use the concentrated alunitic kaolins in place of the kaolin being used in a ceramic factory. The properties of the ceramic tiles produced were then compared with those of the factory’s own products. It was finally proven that the use of concentrated alunitic kaolin at a ratio of 20% improved the physical properties of ceramic tiles of the factory and that the sulphur within the kaolin was tolerated.

Biofilm colonization of Mycobacterium abscessus: New threat in hospital-acquired surgical site infection

IntroductionRapidly growing non-tuberculous mycobacteria (NTM) are hazardous cause of post-operative soft tissue infection leading to nosocomial outbreaks following various surgical procedures, especially laparoscopic surgeries using heat sensitive, non-autoclavable surgical instruments. MethodologySurgery department of our hospital noticed increase in rate of post-laparoscopic abdominal port site infection (PSI) and informed the Microbiology Department. A prospective investigational study of defined cases with the aim of source tracing and formulation of infection control measures was initiated. Pus or wound scrapings were collected and processed for aerobic, anaerobic bacteria and Mycobacterium, both by staining and culture. Environmental samples were collected from laparoscopic instruments, and different parts of operation theatre (OT). Mycobacterial isolates were speciated by line probe assay. All the cases were treated with clarithromycin and ofloxacin±amikacin. ResultsAmong 15 cases of PSI, 11 patients had undergone laparoscopic cholecystectomy, 3 had laparoscopic mesh hernioplasty and one had laparoscopic orchidopexy. Of the 13 pus/discharge specimens examined, 11 revealed growth of NTM. All the isolates were identified as Mycobacterium abscessus by line probe assay. Scraping of biofilm from the disinfectant tray also produced growth of the same organism. Plastic trays used for disinfectants were replaced with metal trays and instructed to do mechanical scrubbing before autoclaving at regular interval. No similar PSI cases were notified after those measures were taken, till date. ConclusionsThis study has shown the need of culture and identification of pathogens causing persistent post surgical wound infections and illuminated importance of rapid source tracing in resource constraint situation which could control outbreak.

Study on ultrasonic-assisted electrochemical honing of bevel gears

Electrochemical honing of gears is a productive, high-accuracy, micro-finishing and long tool life gear finishing process in which material is removed by combined action of electrolytic dissolution and mechanical scrubbing action. The use of ultrasonic-assisted electrochemical honing of gears is first proposed, and it may help to enhance the process performances of the classical electrochemical honing process by scrubbing the complete surface of the gear tooth. In this technique, the honing gear is attached on the ultrasonic vibrator to provide the ultrasonic vibrations on the workpiece surface. The focus is on an optimization of the process parameters of ultrasonic-assisted electrochemical honing of bevel gear made of AISI 1040 carbon steel. The result of experiments reveals that the applied high ultrasonic frequency (kHz) on the workpiece has the maximum influence on the process performance. The maximum percentage improvement in average and maximum surface roughness using ultrasonic-assisted electrochemical honing of bevel gear is 91.04 and 71.98, respectively. The results confirm that the ultrasonic-assisted electrochemical honing can produce a better tooth surface roughness than the electrochemical honing. This will improve bevel gear efficiency and reliability in operation.

A Ring Type Residue Formation in Post Cu CMP Cleaning

A chemical mechanical planarization (CMP) of copper (Cu) damascene structure is prone to defect formation due to variety of chemical agents in slurry and chemical complex formation. In post CMP cleaning process, which should remove such defects, a mechanical scrubbing of wafer by porous and elastic brushes are eligibly used. Although, chemical effects are the main mechanism of defect detachment and dissolution during cleaning process, mechanical effects also play key role by transportation of chemical agent and discharge of reacted species. The most relevant defect caused by mechanical effect is ring shaped scratch due to exceeding contact pressure. In this study, however, we focused on ring shaped residue after post Cu CMP cleaning which is not caused by direct solid contact. To investigate root cause, analysis are carried out such as chemical composition of residue, surface charge map on a wafer, kinematic analysis on brush and wafer motion, and fluid dynamic simulation on chemical motion. In conclusion, it is revealed that both chemical and mechanical effects are interacted to form ring shaped residue. Elimination of defects by chemical effect is suppressed by mechanical motion of brush and chemical fluid. Figure 1

Factors Affecting Electrochemical Honing of SS-316

Electrochemical Honing (ECH) is a process of precision finishing of functional surfaces with the use of the electrical and mechanical energy. It is reported that the 90 percent of the material is removed by electrochemical machining (ECM) process and remaining 10 percent by mechanical scrubbing, which shows the electrical energy is the main constituent in the ECH process. Basically, electrical energy is combined with chemical to form an electrolysis dissolution to remove material from the workpiece surface. This work presents a study for the factors affecting the electrochemical honing of SS-316 turned surfaces, especially the processing time and electrolyte composition. The percentage improvement in surface roughness (Ra, Rt) and out-of-roundness (OOR) as a monitored output of ECH were determined. The results are finally furnished with the aim to generalize a useful guideline for the user to enable proper selection of conditions for obtaining good surface quality.

Efficacy of Mechanical versus Non-Mechanical Sterile Preoperative Skin Preparation With Chlorhexidine Gluconate 4% Solution.

To compare the efficacy of sterile preoperative skin antisepsis using either a 5-minute mechanical preparation or 5-minute non-mechanical preparation with chlorhexidine gluconate 4% solution. Matched design, ANOVA. Healthy adult Thoroughbred horses (n = 30). Each horse had both surgical preparation methods randomly assigned to identical sites on the left or right upper thigh. Prepared sites were sampled and cultured for bacteria after each preparation step. Mechanical and non-mechanical preparation techniques significantly reduced bacteria isolated from surface swab samples compared with samples taken from unprepared skin and after the preliminary rough prepared skin (P < 0.05). No difference in the number of skin-associated bacteria was detected between the mechanical and non-mechanical sterile preoperative preparation techniques (P = 0.77). Ten species of bacteria were identified by 16s PCR after final skin preparation. Pre-surgical skin preparation without repeated mechanical scrubbing using chlorhexidine gluconate 4% solution (total contact time, 225 seconds) is effective in reducing bacterial counts.

PRE-CONCENTRATION AND FLOTATION OF ALUNITIC KAOLIN AND ITS POSSIBLE USE IN CERAMIC TILE INDUSTRY

The aim of this research was to remove sulphur and alunitic parts by the flotation method from alunitic kaolin obtained from the Balikesir-Sindirgi region of Turkey, which is not currently used by the ceramic industry because of its high sulphur content. In the process, mineral alunite was floated while kaolinite was depressed. The effect of pre-concentration on the flotation process was also investigated. Pre-concentration included several processes such as wetting, mechanical scrubbing, and screening for removal of fine alunite particles and colouring oxides from kaolin as well as screening after consecutive milling for the separation of hard minerals such as quartz from kaolin. After the pre-concentration and flotation processes, kaolin concentrate having a SO3 content of 0.48% was obtained with a sulphur removal efficiency of 88.55%, and this kaolin was coded as F4. Afterwards, the use of F4 kaolin in the ceramic industry was investigated. For this purpose, the F4 kaolin was used in angobe preparation, and the angobes prepared were used for the production of floor and wall tiles. The properties of the angobes were also compared to those of commercial floor and wall tile angobes from a ceramic factory. These tests indicated that the floor and wall tile angobes prepared by using F4 kaolin could be used as an alternative for the angobes currently used by the factory.

The importance of mechanical scrubbing in magnetite-concentrate reverse-flotation

Getting magnetite concentrate with extremely high Fe grade using reverse flotation method has become increasingly important due to the enhanced requirement of iron making industry. The coagulation in magnetite-concentrate flotation system may impose negative effect on flotation performance. This paper combined the DLVO calculation and microscope observation to study the coagulation behavior in the system. The result shows that the coagulation between fine magnetite and coarse silica particle is very likely to occur with energy barrier 1.5×10−18J at pH 10.0, which is much smaller than 1.6×10−17J and 3.3×10−17J for fine magnetite and fine magnetite-coarse magnetite particles. The coating of fine magnetite particle on silica surface was observed under microscope. Mechanical scrubbing increases the concentrate Fe grade and recovery by 1.5% and 8.5% respectively. Magnetite concentrate of 67.9% Fe grade and 71.5% Fe recovery was finally obtained.

Decontamination efficacy of three commercial-off-the-shelf (COTS) sporicidal disinfectants on medium-sized panels contaminated with surrogate spores of Bacillus anthracis.

In the event of a wide area release and contamination of a biological agent in an outdoor environment and to building exteriors, decontamination is likely to consume the Nation’s remediation capacity, requiring years to cleanup, and leading to incalculable economic losses. This is in part due to scant body of efficacy data on surface areas larger than those studied in a typical laboratory (5×10-cm), resulting in low confidence for operational considerations in sampling and quantitative measurements of prospective technologies recruited in effective cleanup and restoration response. In addition to well-documented fumigation-based cleanup efforts, agencies responsible for mitigation of contaminated sites are exploring alternative methods for decontamination including combinations of disposal of contaminated items, source reduction by vacuuming, mechanical scrubbing, and low-technology alternatives such as pH-adjusted bleach pressure wash. If proven effective, a pressure wash-based removal of Bacillus anthracis spores from building surfaces with readily available equipment will significantly increase the readiness of Federal agencies to meet the daunting challenge of restoration and cleanup effort following a wide-area biological release. In this inter-agency study, the efficacy of commercial-of-the-shelf sporicidal disinfectants applied using backpack sprayers was evaluated in decontamination of spores on the surfaces of medium-sized (∼1.2 m2) panels of steel, pressure-treated (PT) lumber, and brick veneer. Of the three disinfectants, pH-amended bleach, Peridox, and CASCAD evaluated; CASCAD was found to be the most effective in decontamination of spores from all three panel surface types.

Association between moderate-to-severe diarrhea in young children in the global enteric multicenter study (GEMS) and types of handwashing materials used by caretakers in Mirzapur, Bangladesh.

Handwashing practices among caretakers of case and control children < 5 years of age enrolled in the Global Enteric Multicenter Study in Mirzapur, Bangladesh were characterized and analyzed for association with moderate-to-severe diarrhea. Soap or detergent ownership was common, yet 48% of case and 47.7% of control caretakers also kept ashes for handwashing, including 36.8% of the wealthiest households. Soap, detergent, and ash were used for multiple hygiene purposes and were kept together at handwashing areas. Caretakers preferred soap for handwashing, but frequently relied on ash, or a detergent/ash mixture, as a low-cost alternative. Moderate-to-severe diarrhea was equally likely for children of caretakers who kept soap versus those who kept ash (matched OR = 0.91; 0.62–1.32). Contact with ash and water reduced concentrations of bacterial enteropathogens, without mechanical scrubbing. Thus, washing hands with ash is a prevalent behavior in Mirzapur and may help diminish transmission of diarrheal pathogens to children.

The role of mechanical instrumentation in the cleaning of root canals

The cleaning and shaping of the root canal is a key procedure in root canal treatment. The aim of cleaning is the removal of tissue remnants and bacterial biofilms in order to allow close adaptation of the root filling to the canal walls. In simple straight canals with a round cross‐section, this aim is easily attained by mechanical instrumentation and irrigation. The task of cleaning presents a greater challenge in oval canals, curved canals, and in canal systems that contain an isthmus. In areas that are inaccessible to mechanical instrumentation, the cleaning greatly depends on the action of sodium hypochlorite, which is used to dissolve and remove all of the remaining tissues and bacterial biofilms. Traditional irrigation with syringe and needle is often ineffective in cleaning such inaccessible areas. Newer irrigation methods allow for better cleaning by facilitating a more effective flow of irrigants; nevertheless, adequate, larger, mechanical preparations are required for the effective use of these methods. An alternative approach is to use a hollow file that adapts itself to the cross‐section of the canal, without excessive enlargement of the canal, thus allowing mechanical scrubbing of the walls with a continuous flow of the irrigant through the file. All cleaning methods reach their limit in cases of long narrow isthmuses that are often inaccessible to mechanical instrumentation; adequate instrumentation is, however, a prerequisite for all cleaning methods.