Journal articles: 'Chemical cleanings'

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Votta, Annamaria, Francesco Pipia, S. Borsari, Enrica Ravizza, Alice C. Elbaz, Mauro Alessandri, Enrico Bellandi, and C. Bresolin. "Influence of Wet Cleaning on Tungsten Deposited with Different Techniques." Solid State Phenomena 145-146 (January 2009): 197–200. http://dx.doi.org/10.4028/www.scientific.net/ssp.145-146.197.

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Tungsten is a metal widely used for interconnections. As a consequence of more stringent requirements in terms of aspect ratio deriving from device shrinking, the filling of W plugs is becoming more and more critical and new deposition techniques need to be employed to properly fill contacts and trenches. For example ALD nucleation layers need to be coupled to CVD deposition. Since physical-chemical properties of W are heavily influenced by deposition techniques, the effect of wet cleanings on different kind of W needs to be fully understood in order to avoid any kind of W corrosion or recession during wet cleaning with W exposed. In this paper the effect of several chemicals commonly used in BEOL wet cleanings for polymer removal, has been investigated on W films deriving from both CVD and ALD deposition techniques.

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Fedorova, А. Yu, and Е. N. Bushuev. "Determining of kinetic characteristics of chemical cleaning from scale deposits in steam boiler generating tubes." Vestnik IGEU, no. 4 (2019): 5–11. http://dx.doi.org/10.17588/2072-2672.2019.4.005-011.

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Reliable operation of steam boilers is maintained by periodic in-service cleanings of the internal surfaces of the steam-water path. Such cleanings can be made with traditional and new acid cleaning agents. The nec-essary condition for developing an effective chemical cleaning program is predicting its required duration taking into account the properties of the detergent used and the contamination of the metal surface. Insufficient duration of this operation leads to increased residual contamination, while excessive duration – to metal dissolution. Traditionally, the required time for chemical cleaning is evaluated according to the results of laboratory experiments. The aim of this study is to obtain analytical dependencies and characteristics describing the kinetics of the acid stage of steam boiler chemical cleaning. The laboratory studies of the acid stage of chemical cleaning of samples of high-pressure steam boiler generating tubes were performed by the chemical etching method. The rates and completeness of the removal of lumpy and uniform deposits by acid reagents were also determined. The method of mathematical modeling was used to obtain the kinetic equation. The conditional purification rate constants for this equation were found by the methods of statistical processing of laboratory results. A description of the scale removal rate from the inner surface of the steam generating tubes is proposed as a first-order kinetic equation depending on their specific contamination and reagent washing solution acidity. The equation allows calculating the required duration of chemical cleaning for providing a given value of specific residual contamination of the metal surface. According to the results of the laboratory studies, the conditional rate constants of purification were determined using proven detergent reagents and types of scale. The adequacy of the obtained results is ensured by their consistency with real-life data. The results of the study can be used to select the technology of acid stages of chemical cleaning of lumpy and uniform deposits and justify their duration for providing standard values of specific residual contamination of the surface of steam generating tubes of drum boilers.

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Gabarrón, S., M. Gómez, H. Monclús, I. Rodríguez-Roda, and J. Comas. "Ragging phenomenon characterisation and impact in a full-scale MBR." Water Science and Technology 67, no. 4 (February 1, 2013): 810–16. http://dx.doi.org/10.2166/wst.2012.633.

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Although there are few studies about clogging phenomenon in the peer-reviewed literature, it is considered one of the main operational challenges by membrane bioreactor (MBR) practitioners. This study presents data from the performance of a full-scale MBR affected by clogging, and ragging in particular. An evaluation of the efficiencies of different applied cleaning methods revealed the acid recovery cleaning to be more efficient than the basic recovery cleanings, although all maintenance cleanings were largely ineffective in recovering membrane permeability. Only declogging cleaning through the manual removal of the accumulated solids was found to be efficient, indicating that such solids were substantially unremoved by chemical cleaning. Moreover, reclogging following manual cleaning demonstrated a propensity for rapid clogging – within a period of 10 days over which the permeability returned to 68 and 88% of the pre-cleaned state. The analysis of the feedwater indicated suspended textile fibres (>70% cotton) to be present at a concentration of more than 40 mg·L−1, ∼90% being smaller than 1 mm (0.06–0.4 mm). These small lengths of filaments evidently pass through pre-treatment and are retained on the membrane surface, forming ‘rags’ within the membrane module, notwithstanding the routine high quality of sludge reflected in the capillary suction time and filterability measurements. Pre-treatment improvement, manual cleaning and permeate flux reduction are the only options to minimise ragging impact over MBR performance.

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Bdiri, Bensghaier, Chaabane, Kozmai, Baklouti, and Larchet. "Preliminary Study on Enzymatic-Based Cleaning of Cation-Exchange Membranes Used in Electrodialysis System in Red Wine Production." Membranes 9, no. 9 (September 3, 2019): 114. http://dx.doi.org/10.3390/membranes9090114.

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The use of enzymatic agents as biological solutions for cleaning ion-exchange membranes fouled by organic compounds during electrodialysis (ED) treatments in the food industry could be an interesting alternative to chemical cleanings implemented at an industrial scale. This paper is focused on testing the cleaning efficiency of three enzyme classes (β-glucanase, protease, and polyphenol oxidase) chosen for their specific actions on polysaccharides, proteins, and phenolic compounds, respectively, fouled on a homogeneous cation-exchange membrane (referred CMX-Sb) used for tartaric stabilization of red wine by ED in industry. First, enzymatic cleaning tests were performed using each enzyme solution separately with two different concentrations (0.1 and 1.0 g/L) at different incubation temperatures (30, 35, 40, 45, and 50 °C). The evolution of membrane parameters (electrical conductivity, ion-exchange capacity, and contact angle) was determined to estimate the efficiency of the membrane′s principal action as well as its side activities. Based on these tests, we determined the optimal operating conditions for optimal recovery of the studied characteristics. Then, cleaning with three successive enzyme solutions or the use of two enzymes simultaneously in an enzyme mixture were tested taking into account the optimal conditions of their enzymatic activity (concentration, temperatures, and pH). This study led to significant results, indicating effective external and internal cleaning by the studied enzymes (a recovery of at least 25% of the electrical conductivity, 14% of the ion-exchange capacity, and 12% of the contact angle), and demonstrated the presence of possible enzyme combinations for the enhancement of the global cleaning efficiency or reducing cleaning durations. These results prove, for the first time, the applicability of enzymatic cleanings to membranes, the inertia of their action towards polymer matrix to the extent that the choice of enzymes is specific to the fouling substrates.

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Kucera, Jane. "Biofouling of Polyamide Membranes: Fouling Mechanisms, Current Mitigation and Cleaning Strategies, and Future Prospects." Membranes 9, no. 9 (August 30, 2019): 111. http://dx.doi.org/10.3390/membranes9090111.

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Reverse osmosis and nanofiltration systems are continuously challenged with biofouling of polyamide membranes that are used almost exclusively for these desalination techniques. Traditionally, pretreatment and reactive membrane cleanings are employed as biofouling control methods. This in-depth review paper discusses the mechanisms of membrane biofouling and effects on performance. Current industrial disinfection techniques are reviewed, including chlorine and other chemical and non-chemical alternatives to chlorine. Operational techniques such as reactive membrane cleaning are also covered. Based on this review, there are three suggested areas of additional research offering promising, polyamide membrane-targeted biofouling minimization that are discussed. One area is membrane modification. Modification using surface coatings with inclusion of various nanoparticles, and graphene oxide within the polymer or membrane matrix, are covered. This work is in the infancy stage and shows promise for minimizing the contributions of current membranes themselves in promoting biofouling, as well as creating oxidant-resistant membranes. Another area of suggested research is chemical disinfectants for possible application directly on the membrane. Likely disinfectants discussed herein include nitric oxide donor compounds, dichloroisocyanurate, and chlorine dioxide. Finally, proactive cleaning, which aims to control the extent of biofouling by cleaning before it negatively affects membrane performance, shows potential for low- to middle-risk systems.

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Breitenstein, Lena, Florian Sevenig, Damian Pysch, Christiane Gottschalk, Martin Hermle, and Wilhelm Warta. "Simple Wet-Chemical Cleanings for High-Efficiency Silicon Solar Cell Applications." Solid State Phenomena 187 (April 2012): 325–28. http://dx.doi.org/10.4028/www.scientific.net/ssp.187.325.

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Simple two-step wet-chemical cleans composed of an oxidizing step with in water dissolved ozone followed by an etching step have been studied for high-efficient hetero-junction silicon solar cell applications. For this purpose flat Si (111) samples passivated with amorphous silicon have been investigated. The effect of nanoroughness of the crystalline silicon surface on the minority carrier lifetime is shown. An influence of the storage time between cleaning and a-Si:H deposition was found and can partly be attributed to changes in surface roughness and native oxide growth.

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Portes Canongia, Ana Carolina, Daniela Sales Alviano Moreno, Leida Gomes Abraçado, Matheus Melo Pithon, and Mônica Tirre Araújo. "Effectiveness of methods for cleaning arch wire: an in vitro study." Bioscience Journal 37 (February 25, 2021): e37017. http://dx.doi.org/10.14393/bj-v37n0a2021-55339.

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The aim of this study was to evaluate various methods of removing bacterial and fungus biofilm, to simulate orthodontic arch wires cleaning before reinsertion in the patients appliance. Rectangular Nickel Titanium (NiTi), Stainless Steel (SS) and Titanium Molybdenum (TMA) wires were divided into five groups, then contaminated with strains of Streptococcus mutans and Candida albicas. Four segments of each group served as control and were not contaminated. Six cleanings methods were used to remove the biofilm: cotton roll and a chemical agent (chlorhexidine, sodium hypochlorite, 70% alcohol), cotton roll and water, steel woll and immersion on enzymatic detergent. There was a control group not decontaminated Then wires were placed in broth separately, and after an incubation period the optical density (OD) was measured, observing whether there was microbial growth. A wire segment of each subgroup of SS 3M® was taken to the Scanning Electron Microscope (SEM) for visualization of the treatment response. The results were submitted to one-way ANOVA test and Tukey post-test. With the exception of 70% alcohol, the disinfection means behaved similarly regardless the type of wire. Two percent Chlorhexidine and 1% Sodium Hypochlorite totally removed the microorganisms while other agents left a high microbial concentration. Chemical cleaning is necessary to remove biofilm in orthodontic wires; 1% Sodium Hypochlorite and 2% Chlorhexidine are good disinfectants for this purpose.

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Liikanen, Riina, Jukka Yli-Kuivila, and Risto Laukkanen. "Efficiency of various chemical cleanings for nanofiltration membrane fouled by conventionally-treated surface water." Journal of Membrane Science 195, no. 2 (January 2002): 265–76. http://dx.doi.org/10.1016/s0376-7388(01)00569-5.

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Bel-Berger, Patricia, and Terri Von Hoven. "Effects of Mechanical Cleaning on Cotton Fibers: Part III: Effects of Card Wire Condition on White Specks." Textile Research Journal 67, no. 12 (December 1997): 857–65. http://dx.doi.org/10.1177/004051759706701201.

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Combinations of gin and mill cleaning sequences have been studied to determine the best way to clean both smooth-leaf and hairy-leaf cottons. The two varieties were subjected to four different levels of lint cleaning at the gin, followed by nine different mill cleaning sequences, for a total of thirty-six samples. All samples were tested for fiber properties (Part II), yarn strength, and fabric strength and appearance. The yarn and fabric properties are reported in this paper. In the middle of the study, the card wire was damaged and subsequently replaced, which presented the opportunity to determine the impact of the card wire's condition on white specks. In addition, image analysis of the fabric samples by Optimas detected the percent white, the percentage of the area of white specks in a specified area of fabric. Because of the variability of white specks, a larger sample size was needed than was available for the mill samples, so only trends can be reported for the mill samples. In general, the more aggressive the cleaning, the higher the percent white. When comparing the effect of ginning, each additional lint cleaner produced an increase in percent white for the worn card wire. The new card wire decreased the percent white overall as compared to the worn card wire. The new card wire samples with three lint cleanings had a significantly higher white speck level than zero, one, or two lint cleaners. Similarly, the harsher the mill cleaning, the higher the percent white. The hairy-leaf variety produced percent white values similar to those for the smooth-leaf cotton for both the old and new card wires. Thus, when confronted with the possibility of a white speck problem, minimal gin cleaning and less aggressive mill cleaning are recommended.

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EGGLESTON, GILLIAN, and ADRIAN MONGE. "HOW TIME BETWEEN CLEANINGS AFFECTS PERFORMANCE AND SUCROSE LOSSES IN ROBERT'S EVAPORATORS." Journal of Food Processing and Preservation 31, no. 1 (February 2007): 52–72. http://dx.doi.org/10.1111/j.1745-4549.2007.00107.x.

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Yang, Jiaqi, Mathias Monnot, Lionel Ercolei, and Philippe Moulin. "Impact of Chlorinated-Assisted Backwash and Air Backwash on Ultrafiltration Fouling Management for Urban Wastewater Tertiary Treatment." Membranes 11, no. 10 (September 27, 2021): 733. http://dx.doi.org/10.3390/membranes11100733.

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To improve membrane fouling management, the NaClO-assisted backwash has been developed to improve permeability maintenance and reduce the need for intensive chemical cleanings. This study is aimed to focus on the efficiency of NaClO-assisted backwash in real UF pilot scale and with periodic classic backwash (CB) and air backwash (AB). The impacts on hydraulic filtration performance, physicochemical properties of membrane material under different addition frequencies of NaClO, and the performance of chlorinated CB and AB will be discussed. In result, 10 mg Cl2 L−1 NaClO addition in backwash water is confirmed to greatly improve the overall filtration performance and backwash cleaning efficiency. One condition stands out from the other due to better control of irreversible fouling, less NaClO consumption in 10 years prediction, sustainable and adaptable filtration performance, and less potential damage on the physicochemical properties of the membrane. Additionally, it can be inferred from this experiment that frequent contact with NaClO induced some degradation on the PES-made UF membrane surface properties. To retain the best state of UF membrane on anti-fouling and qualified production, the optimized condition with more frequent NaClO contact was not suggested for long-term filtration.

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Pozo-Antonio, J. S., P. Barreiro, G. Paz-Bermúdez, P. González, and A. B. Fernandes. "Effectiveness and durability of chemical- and laser-based cleanings of lichen mosaics on schists at archaeological sites." International Biodeterioration & Biodegradation 163 (September 2021): 105276. http://dx.doi.org/10.1016/j.ibiod.2021.105276.

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Toscano, Alyne, Deisemara Ferreira, and Reinaldo Morabito. "Formulation and MIP-heuristics for the lot sizing and scheduling problem with temporal cleanings." Computers & Chemical Engineering 142 (November 2020): 107038. http://dx.doi.org/10.1016/j.compchemeng.2020.107038.

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Novotny, Jan, Stefan Michna, Iryna Hren, Jaromir Cais, Irena Lysonkova, and Vaclav Svorcik. "PTFE Based Multilayer Micro-Coatings for Aluminum AlMg3 Forms Used in Tire Production." Coatings 11, no. 2 (January 21, 2021): 119. http://dx.doi.org/10.3390/coatings11020119.

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The basic prerequisite for obtaining the coating of good quality is the production of a layer without the occurrence of surface defects. A possible solution to the occurrence of defects on the functional surface of the form is the application of a polytetrafluoroethylene (PTFE)-based coating. The coating helps to reduce surface roughness and “smooth” defects like pores and micro-shrinkage. For this reason, a new type and methodology of the coating were prepared to achieve more production cycles between the individual cleaning processes during the production of a tire. The subject of the study was the analysis of surface-applied micro-coatings, including the analysis of chemical composition by using energy-dispersive X-ray (EDX) and microstructure in the area of coatings. Detailed microstructural characterization of Alfipas 7818 and Alfiflon 39 and its imaging of surface structures were studied using atomic force microscopy. To examine the surface layer of the coatings, metallographic specimens of cross-sections (by means of a mold) were prepared and examined by light and electron microscopy. This new multilayer micro-coating with a thickness of 20–25 μm has been found to prevent form contamination during tire production and to extend production cycles by 200–400% between process cleanings. This finding was actually tested in the production of tires in the environment of a large manufacturing company.

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Ruigómez, Ignacio, Enrique González, Luis Rodríguez-Gómez, and Luisa Vera. "Fouling control strategies for direct membrane ultrafiltration: Physical cleanings assisted by membrane rotational movement." Chemical Engineering Journal 436 (May 2022): 135161. http://dx.doi.org/10.1016/j.cej.2022.135161.

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Matsui, Y., T. Aizawa, M. Suzuki, and Y. Kawase. "Removal of geosmin and algae by ceramic membrane filtration with super-powdered activated carbon adsorption pretreatment." Water Supply 7, no. 5-6 (December 1, 2007): 43–51. http://dx.doi.org/10.2166/ws.2007.080.

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The musty-earthy taste and odour caused by the presence of geosmin and other compounds in tap water are major causes of consumer complaints. Although ozonation and granular activated carbon (GAC) adsorption have been practiced in water-treatment plants to remove these compounds effectively, two major problems associated with the application of these processes – formation of stringently regulated bromate ions by ozonation and unhygienic invertebrate colonisation of GAC filters – are still to be resolved. This research advanced the process of adsorption by powdered activated carbon (PAC) by reducing its particle size to the submicrometre range for microfiltration pretreatment. Adsorption pretreatment by using this super (S)-PAC removed the geosmin with vastly greater efficiency than by normal PAC. Removal was attained in a much shorter contact time and at a much lower dosage. The S-PAC was also beneficial in attenuating the transmembrane pressure rises that occurred between both physical backwashings and chemical cleanings.

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Ichiki, A., F. Ido, and T. Minami. "Runoff characteristics of highway pollutants based on a long-term survey through a year." Water Science and Technology 57, no. 11 (June 1, 2008): 1769–76. http://dx.doi.org/10.2166/wst.2008.268.

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Highway pollutants generated mainly from traffics are repeating accumulation, raise, drift and move on the highways. Some of them are removed by road cleanings done regularly, the others are flushed by stormwater into receiving water. The objectives of this study are to survey characteristics of the highway pollutants, and to quantify their behavior on the highways. The study area is a part of Meishin Expressway running through the main island of Japan. Surveys on pollutant runoff from the highway were done for all storm events through one year from December 2004 to November 2005. For the surveys, samples were collected by continuous water sampling during storm events. And chemical substances in each sample such as SS, TOC, TN, TP, heavy metals and polycyclic aromatic hydrocarbons (PAHs) for each class of particle size were measured. Using the results of the survey, characteristics of pollutant runoff during storm events were examined. And it cleared the basic unit loads for the highway pollutants throughout a year. As a result, some significant knowledge for the environmental management of highway pollution has been obtained.

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Morales, Yair G., and Pia Lipp. "Deacidification through calcium carbonate dosing in combination with ultrafiltration." Journal of Water Supply: Research and Technology-Aqua 70, no. 8 (November 22, 2021): 1111–20. http://dx.doi.org/10.2166/aqua.2021.030.

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Abstract Soft acidic waters are often treated for drinking water purposes by using limestone filters to attain chemical equilibrium. The present study investigated the process parameters of a relatively new process combination in which powdered calcium carbonate (CaCO3) was added prior to an ultrafiltration (UF). In order to reach the targeted pH value (≥7.8), dosing concentration, type of material and retention time were evaluated in pilot-scale experiments. The deacidification followed the same kinetics as for limestone filtration and yielded similar filtrate characteristics with dosing concentrations of 20 and 40 g/L CaCO3. No significant increase in transmembrane pressure was observed during the operation of a pilot-scale UF module at low flux (34 L m−2 h−1). Critical flux was determined in a laboratory scale to evaluate the potential impact of CaCO3 particles on the UF operation. Stepping-flux experiments revealed the presence of fouling only at high-dosing concentrations, resulting in a critical flux of 55 L m−2 h−1. At a higher flux, a CaCO3-fouling layer was formed, which decreased the membrane's permeability by 20% over 5 h. Considering that effective air-enhanced backwash and acidic chemical cleanings will be implemented in large-scale applications, the investigated process combination promises to be an appropriate treatment technology for turbid and soft acidic waters.

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Alresheedi, Mohammad T., Onita D. Basu, and Benoit Barbeau. "Chemical cleaning of ceramic ultrafiltration membranes – Ozone versus conventional cleaning chemicals." Chemosphere 226 (July 2019): 668–77. http://dx.doi.org/10.1016/j.chemosphere.2019.03.188.

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Gaździk, Barbara, Roman Kempiński, Zbigniew Paćkowski, and Kamil Pomykała. "Innowacyjne środki myjąco-konserwujące i oleje ochronne." Nafta-Gaz 75, no. 7 (July 2019): 430–44. http://dx.doi.org/10.18668/ng.2019.07.07.

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Angermann, Heike, Klaus Wolke, Christiane Gottschalk, Anamaria Moldovan, Maurizio Roczen, Jens Fittkau, Martin Zimmer, and Jochen Rentsch. "Surface Charge and Interface State Density on Silicon Substrates after Ozone Based Wet-Chemical Oxidation and Hydrogen-Termination." Solid State Phenomena 195 (December 2012): 314–17. http://dx.doi.org/10.4028/www.scientific.net/ssp.195.314.

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For more than 20 years, the application of ozone dissolved in pure deionised water (DIW-O3) has been investigated for wafer-cleaning and resist stripping applications in the semiconductor industry [, , ]. To reduce chemical consumption and disposal costs as well as to improve cleaning efficiency, DIW-O3 is used in semiconductor wet cleaning processes as an alternative to traditional sulphuric acid peroxide (H2SO4/H2O2) [] and RCA [] cleans. Silicon solar cell fabrication includes multiple wet cleaning steps involving large amounts of chemicals. In Si substrate manufacturing the wet-chemical oxidation of substrate surface is used mainly for three purposes: (i) the removal of surface contamination and surface micro-roughness by different cleaning and smoothing procedures in H2O2 containing solutions (RCA I and RCA II) [5], in H2SO4/H2O2 [4], (ii) the preparation of hydrophilic surfaces for subsequent layer deposition [,] and (iii) the fabrication of thin oxide layers []. Chemical consumption could be reduced by replacing some of these chemicals with a mixture of pure deionised water with dissolved ozone for cleaning and surface conditioning. The kinetics of wet-chemical oxidation in DIW-O3 were recently investigated by ellipsometrical measurements of oxide thicknesses (ox>) [3,6,7], by SPV-measurements [7,], by contact angle measurements as well as by quasi-steady-state photo conductance (QSSPC) measurements [7].

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Barkhudarov, E. M., I. A. Kossyi, Yu N. Kozlov, S. M. Temchin, M. I. Taktakishvili, and Nick Christofi. "Multispark Discharge in Water as a Method of Environmental Sustainability Problems Solution." Journal of Atomic and Molecular Physics 2013 (July 21, 2013): 1–12. http://dx.doi.org/10.1155/2013/429189.

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Multispark discharge excited in water is described, and its useful physical and chemical properties are discussed in the light of some environmental issues. Discharge of such a type generates hot and dense plasmoids producing intense biologically active UV radiation and chemically active radicals, atoms, and molecules. Simultaneously, discharge creates strong hydrodynamic perturbations and cavitation bubbles. Particular attention is given to factors influencing on water purity with special reference to discharge application for effective sterilization of water and its cleaning of harmful chemicals. The gas discharges of this type show considerable promise as a means for solving some actual plasma-chemical problems. The above-mentioned discharge properties have been demonstrated in a series of laboratory experiments, which proved the efficiency of disinfection of potable and waste water, water cleaning of pesticide (herbicide) contaminations, and conversion (recovery) of natural methane.

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Grant, Donald, Dan Smith, Peter Palm, Faa-Ching Wang, Danny Charest, Juan Campaneria, Loh Wai, et al. "Design and Certification of High Purity Delivery Systems for Semiconductor Wafer Cleaning Chemicals." Journal of the IEST 37, no. 6 (November 1, 1994): 32–40. http://dx.doi.org/10.17764/jiet.2.37.6.r62726744v254354.

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The wafer cleaning procedures used in new semiconductor manufacturing facilities require extremely high purity chemicals. Delivering chemicals of this quality requires careful management of the chemicals from their manufacturing site to the points of use (POUs) within the wafer fabrication facility (fab). Chemical management includes proper chemical production, transportation to the wafer fab and design and operation of the chemical delivery system within the fab. This paper describes the technology used to supply 15 different types of chemicals to more than 60 POUs in the TECH Semiconductor wafer fab in Singapore. The certification and continuous monitoring program confirms sub-ppb chemical delivery with particle concentrations of < 3 particles/ml at ≥ 0.2 μm. Several challenges associated with the initial design and installation of the chemical delivery system and their resolution are also described.

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Kashkoush, Ismail, Rich Novak, and Eric Brause. "In-Situ Chemical Concentration Control for Wafer Wet Cleaning." Journal of the IEST 41, no. 3 (May 14, 1998): 24–30. http://dx.doi.org/10.17764/jiet.41.3.f573u112344t8pr5.

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This paper demonstrates the use of conductivity sensors to monitor and control the concentration of RCA cleaning and hydrofluoric acid (HF) etching solutions. Commercially available electrodeless conductivity sensors were used to monitor and control the concentration of these process solutions. A linear relationship between the conductivity of the solution and the chemical concentration was obtained within the range studied. A chemical injection scheme was developed to maintain the chemical concentration within specified limits. Different concentrations of RCA-based cleaning solutions and HF solutions were investigated. Results show that these techniques are suitable for monitoring and controlling the concentration of chemicals in the process tanks for better process control. These techniques provide low cost of ownership of the process by using dilute chemicals and longer bath life (i.e., a more environmentally sound process).

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Kweskin, Sasha J., and Larry W. Shive. "Aluminum Reduction in SC1." Solid State Phenomena 219 (September 2014): 28–31. http://dx.doi.org/10.4028/www.scientific.net/ssp.219.28.

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RCA clean has evolved since 1965 [1]. Typically used before critical thermal steps, depositions/etches, or after strip operations, these solutions are robust and reliable. Stringent semiconductor demands of shrinking feature size, increased contamination sensitivity and cost pressure have led to cleaning projects that improve performance and reduce chemical usage. One of the sources of contamination is the process chemicals themselves, where wafers are exposed to chemicals for etching or cleaning. Concerns over contamination are compounded in wet benches where chemical baths are re-circulated for periods up to 24 hours. Metal impurities can arise from insufficiently pure chemicals or water, tanks, carriers, plumbing components, chemical containers, incoming wafers and handling equipment. Strict chemical, DIW and material specifications as well as dilute chemistry and reduced temperature have benefited the industry as a whole. Trends such as lower temperature/concentration SC1, and higher temperature/concentration SC2 have reached a point of diminishing returns for metal contamination reduction. In the same way, chemical and water purity are well below detection, so improvements are difficult to quantify.[2]

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HARADA, TANEOMI. "Coal cleaning course. 4. Chemical cleaning." Journal of the Fuel Society of Japan 67, no. 5 (1988): 342–52. http://dx.doi.org/10.3775/jie.67.342.

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Christoph, Stiepani, Ammann Franz, Jones Dennis, Evans Sarah, and Harper Kayla. "ICONE19-43325 Chemical Cleaning as an Essential Part of Steam Generator Asset Management." Proceedings of the International Conference on Nuclear Engineering (ICONE) 2011.19 (2011): _ICONE1943. http://dx.doi.org/10.1299/jsmeicone.2011.19._icone1943_144.

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Gruskevica, Kamila, Martins Strods, Janis Rubulis, and Linda Mezule. "CLEANING OF CERAMIC ULTRAFILTRATION MEMBRANES AFTER FILTRATION OF HAY HYDROLYSATE." ENVIRONMENT. TECHNOLOGIES. RESOURCES. Proceedings of the International Scientific and Practical Conference 3 (June 16, 2021): 89–94. http://dx.doi.org/10.17770/etr2021vol3.6579.

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Hydrolysis of the lignocellulosic biomass results in the release of high-value chemicals that during industrial processing can be recovered with membrane technologies. To maintain an effective performance of the membranes used in the technological processing of biomass, their regular cleaning is essential. Although several guidelines may be found for membrane cleaning in the cases of organic fouling, the data for cleaning membranes fouled by hydrolyzed lignocellulosic biomass is limited. Current research is aimed to evaluate physical (air backpulse) and common cheap chemical membrane cleaning methods. The results showed that air backpulse alone had a minor (9%) effect on the membrane cleaning. The alternation of NaOH (1 %) solution with the NaClO (200 mg/L of Free chlorine) was the most effective approach for membrane cleaning. The cleaning effectiveness was 95.1 % for 50 nm membrane and 89 % for 200 nm membrane, indicating that membranes used for hydrolyzed lignocellulosic biomass filtration can be effectively cleaned using affordable and accessible chemicals.

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Mysak, Yo S., V. S. Fedoryshyn, S. Yo Mysak, T. P. Kovalenko, and O. O. Khanas. "STUDYING OF THE OPERATION STEAM CHEMICAL CLEANING OF BOILER TGMP-344A OF MINSK TPP-4." Energy Technologies & Resource Saving, no. 4 (December 20, 2017): 20–27. http://dx.doi.org/10.33070/etars.4.2017.04.

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The steam chemical cleaning of the internal surfaces of the screen tubes of the boiler TGMP-344A of Minsk TPP-4 was developed by the engineers of Private Company «LvivORGRES» and implemented in production. The methods and stages of its conduct are presented. The principal scheme of operation steam chemical cleaning of the boiler TGMP-344A and its description is given. The list of devices for controlling the parameters of circulation and steam purging is presented. A table of the chemicals used for steam chemical purification was submitted. Comparative results of contaminations of heating surfaces of the boiler before and after the steam chemical cleaning are presented. It is shown that the application of steam chemical cleaning of the boiler provides a significant decreasing in the formation of new deposits on the internal surfaces of the boiler screen tubes. After using of this technology, 94 % of deposits were removed from the steam-water path of the boiler, compared with the initial contamination, and it was determined the removed amount of iron in terms of Fe2O3 is 3464 kg. Bibl. 6, Fig. 1, Tab. 2.

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Carder, Melanie, Martin J. Seed, Annemarie Money, Raymond M. Agius, and Martie van Tongeren. "Occupational and work-related respiratory disease attributed to cleaning products." Occupational and Environmental Medicine 76, no. 8 (June 5, 2019): 530–36. http://dx.doi.org/10.1136/oemed-2018-105646.

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ObjectivesExposure to cleaning products has been associated with adverse respiratory outcomes. This study aimed to investigate the medically reported incidence, trends in incidence and occupational determinants of work-related respiratory disorders attributed to cleaning agents and to explore the role of ‘Quantitative Structure Activity Relationships’ (QSAR) in corroborating the identification of chemical respiratory sensitisers.MethodsRespiratory diagnoses attributed to cleaning agents were extracted from The Health and Occupation Research (THOR) surveillance network, 1989–2017. Incidence, trends in incidence and incidence rate ratios by occupation were investigated. Agents were classified by chemical type and QSAR hazard indices were determined for specific organic chemicals.ResultsApproximately 6% (779 cases) of the (non-asbestos) THOR respiratory cases were attributed to cleaning agents. Diagnoses were predominantly asthma (58%) and inhalation accidents (27%) with frequently reported chemical categories being aldehydes (30%) and chlorine/its releasers (26%). No significant trend in asthma incidence (1999–2017) was observed (annual average change of −1.1% (95% CI −4.4 to 2.4)). This contrasted with a statistically significant annual decline in asthma incidence (−6.8% (95% CI −8.0 to −5.6)) for non-cleaning agents. There was a large variation in risk between occupations. 7 of the 15 organic chemicals specifically identified had a QSAR generated hazard index consistent with being a respiratory sensitiser.ConclusionSpecific occupations appear to be at increased risk of adverse respiratory outcomes attributed to cleaning agents. While exposure to agents such as glutaraldehyde have been addressed, other exposures, such as to chlorine, remain important. Chemical features of the cleaning agents helped distinguish between sensitising and irritant agents.

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Kulkarni, Prachi, Megan Shoff, and Anne Lucas. "Comparison of Test Methods To Screen For Residual Chemical Contamination On Medical Device Surfaces." Biomedical Instrumentation & Technology 46, no. 5 (September 1, 2012): 388–94. http://dx.doi.org/10.2345/0899-8205-46.5.388.

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Abstract Reprocessing medical devices involves several steps including cleaning and disinfection or sterilization. Chemical residuals can occur at various stages of reprocessing. These residues could interfere with device function and potentially harm patients. These solutions are composed of a combination of various chemicals and their residues are highly diluted post rinsing, therefore, it is difficult to find a sensitive and rapid method to detect toxicity due to chemical residues. This study focused on (1) finding the levels of residues that are cytotoxic using two mammalian cell lines and Daphnia magna, and (2) evaluating two test methods, Total Organic Carbon (TOC) and the Luminescent Bacteria Test (LBT), to measure residual chemicals levels. The two mammalian cell lines were equal in their cytotoxicity responses. However, Daphnia were more sensitive to some chemical residue than the two mammalian cell lines. TOC and LBT were able to detect the presence of residue well below the levels that were determined to cause mammalian cytotoxicity. LBT was more sensitive for some chemicals and TOC for others, both in solution and in simulated cleaning and rinsing for the limited number of solutions tested in this study.

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Hantak, Maggie M., Daniel J. Paluh, and Ralph A. Saporito. "Bufadienolide and alkaloid-based chemical defences in two different species of neotropical anurans are equally effective against the same arthropod predators." Journal of Tropical Ecology 32, no. 2 (March 2016): 165–69. http://dx.doi.org/10.1017/s0266467416000055.

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Abstract:Defensive chemicals in anuran skin secretions function in protection against potential predators. Although studies have demonstrated that particular chemicals are effective against certain predators, very little is known about how different chemicals from different species function against the same predators. Understanding how different chemicals function as a defence against similar predators is fundamental to the ecology and evolution of chemical defences in frogs. In the present study, the defensive function of bufadienolide-based defences in adult Rhaebo haematiticus (Bufonidae) were compared with alkaloid-based defences in adult and juvenile Dendrobates auratus (Dendrobatidae) against the same predators. Most bufonids contain synthesized bufadienolides, whereas dendrobatids contain dietary-derived alkaloids. Predation trials were performed with two potential invertebrate predators, Paraponera clavata (bullet ant) and Cupiennius coccineus (ctenid spider), to determine how these predators respond to two different types of frog chemical defence. The non-chemically defended frog Craugastor fitzingeri served as a control in all predation trials. Our results suggest that bufadienolide defences of R. haematiticus and alkaloid defences of D. auratus are equally effective towards bullet ant and ctenid spider predators. The similar avoidance and cleaning behaviours exhibited by these ants and spiders after contact with bufadienolides and alkaloids suggest that both types of defence are unpalatable to these arthropod predators.

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Krause, S., B. Zimmermann, U. Meyer-Blumenroth, W. Lamparter, B. Siembida, and P. Cornel. "Enhanced membrane bioreactor process without chemical cleaning." Water Science and Technology 61, no. 10 (May 1, 2010): 2575–80. http://dx.doi.org/10.2166/wst.2010.183.

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In membrane bioreactors (MBR) for wastewater treatment, the separation of activated sludge and treated water takes place by membrane filtration. Due to the small footprint and superior effluent quality, the number of membrane bioreactors used in wastewater treatment is rapidly increasing. A major challenge in this process is the fouling of the membranes which results in permeability decrease and the demand of chemical cleaning procedures. With the objective of a chemical-free process, the removal of the fouling layer by continuous physical abrasion was investigated. Therefore, particles (granules) were added to the activated sludge in order to realise a continuous abrasion of the fouling layer. During operation for more than 8 months, the membranes showed no decrease in permeability. Fluxes up to 40 L/(m2 h) were achieved. An online turbidity measurement was installed for the effluent control and showed no change during this test period. For comparison, a reference (standard MBR process without granules) was operated which demonstrated permeability loss at lower fluxes and required chemical cleaning. Altogether with this process an operation at higher fluxes and no use of cleaning chemicals will increase the cost efficiency of the MBR-process.

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Zernov, Anatoly. "Occupational risk management when working with chemicals." Okhrana truda i tekhnika bezopasnosti na promyshlennykh predpriyatiyakh (Labor protection and safety procedure at the industrial enterprises), no. 8 (July 31, 2020): 10–24. http://dx.doi.org/10.33920/pro-4-2008-01.

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Occupational risks associated with the use of chemicals in work are characteristic of specific industries, as well as of everyday processes, such as washing and cleaning of equipment and production facilities, storage and transportation of substances, and handling of hazardous waste. At the conference dedicated to occupational risk management, Anatoly Zernov, a specialist at RiskProf, spoke about chemical hazards, as well as emergency situations in chemical production.

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Liu, Jun Xia, Bing Zhi Dong, and Wei Wei Huang. "Characteristics of Fouled and Chemically Cleaned Membrane." Advanced Materials Research 1073-1076 (December 2014): 751–54. http://dx.doi.org/10.4028/www.scientific.net/amr.1073-1076.751.

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The main objective of this study was to investigate membrane fouling caused by natural organic matter (NOM). Flux measurement, fourier transform spectroscopy (FTIR), scanning electron microscopy (SEM) were employed to compare the surface morphology of fouled membrane and chemically cleaned membrane. Sodium hypochlorite (NaClO), sodium hydroxide (NaOH), hydrochloric acid (HCl) were used as chemical cleaning agents respectively. Flux analysis demonstrated that chemical cleaning have little effect on flux recovery. FTIR spectrometry revealed that polysaccharide and protein took the major responsibility for membrane fouling. SEM showed that foulants filled the pores and blocked the membrane surface which led to the flux decline.

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Hasebe, Rui, Akinobu Teramoto, Tomoyuki Suwa, Rihito Kuroda, Shigetoshi Sugawa, and Tadahiro Ohmi. "Three-Step Room Temperature Wet Cleaning Process for Silicon Substrate." Solid State Phenomena 145-146 (January 2009): 189–92. http://dx.doi.org/10.4028/www.scientific.net/ssp.145-146.189.

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With a progress of device dimension miniaturization, an ultraclean wafer surface is continuously increasing its importance crucial for high quality processing in Silicon Technologies [1]-[8]. Cleaning of silicon wafer surface has been accomplished by RCA wet cleaning in the past [9], where there exists high temperature processes consisting of H2SO4/H2O2/H2O, NH4OH/H2O2/H2O and HCl/H2O2/H2O treatments. Thus, RCA cleaning requires a large number of processing steps, resulting in the consumption of a huge volume of liquid chemicals and UPW, and simultaneously consuming a large volume of clean air exhaust to suppress chemical vapor from getting into the clean room. Moreover, RCA cleaning is used at high temperature and contain alkali solutions, which increase the roughness of the silicon wafer surface [10].

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Haslinger, Michael, M. Soha, S. Robert, M. Claes, Paul W. Mertens, and J. John. "‘Just-Clean-Enough’: Optimization of Wet Chemical Cleaning Processes for Crystalline Silicon Solar Cells." Solid State Phenomena 255 (September 2016): 344–47. http://dx.doi.org/10.4028/www.scientific.net/ssp.255.344.

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Advanced concepts for photovoltaic silicon solar cells, especially high-efficiency n-type solar cells, requires appropriate wet cleaning treatment in order to remove metallic contamination prior to high temperature processes like diffusion and passivation [1]. The cost of the cleaning process should be as low as possible that requires an optimized usage of the chemicals by increasing process tank lifetimes and developing dedicated feed and bleed recipes. The just clean enough concept has been developed to fulfil the needs of PV industry to minimize the consumption of chemicals. When the dominant contamination metal is identified in quality and quantity, a dedicated wet chemical cleaning process can be applied to remove the metal concentration from the semiconductor surface under a specified limit with the minimum volume on cleaning solution. The paper describes how to optimize a dedicated wet cleaning process for prominent metal impurities like Fe, Cu, Cr, Ti, Co and Zn. For each metal an exchange volume is determined to develop a feed and bleed recipe. The accumulation of the metal impurities in the process tank is calculated and process tank lifetimes are predicted.

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Yang, Fajie, Chunman Li, Jing Li, Hongtao Wang, Siyu Wu, and Yanqing Gao. "Study on Chemical Cleaning Agent in Treatment of Abandoned Oil Pipeline." E3S Web of Conferences 118 (2019): 01031. http://dx.doi.org/10.1051/e3sconf/201911801031.

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After pipeline construction burst china energy pipeline industry commonly faced with aging and abandonment problem. The study on pipeline abandonment was still in preliminary state, because there is nearly no pipeline abandonment standards and guidelines. Pipeline cleaning is the first step to dispose the abandoned pipeline to eliminate the risk of environment and safety. In foreign developed countries there are many chemical cleaning agents. But this chemical cleaning agent is not suitable for residual of chines pipeline because of oil difference between china and foreign country. The most of residual in china have a very high paraffin and resin-asphaltenes content. So preparation of chemical cleaning suitable for china residual is a challenge on the technology of abandonment pipeline. In this paper two kinds of chemical cleaning agent were prepared to clean the different type of residual. They are hydrophilic chemical cleaning agent and oil soluble chemical cleaning agent. The result of cleaning project shows that the both kind of chemical cleaning have good performance for the abandoned pipeline. The chemical cleaning agents will assist pipeline company to totally clean the abandoned pipeline to ensure the public safety and environment protection.

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Kretzschmar, Michael, El Mustapha Baira, and Eckart Uhlmann. "Characterization of CO₂ Snow Generation to Increase the Blasting Performance." Applied Mechanics and Materials 794 (October 2015): 255–61. http://dx.doi.org/10.4028/www.scientific.net/amm.794.255.

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Chemical cleaning methods are under strict restrictions due to the legislator, as they are often harmful to environment and health. Therefore, environmentally neutral cleaning methods will gain importance in the future. Alternative cleaning processes like blasting with solid carbon dioxide can substitute such harmful chemicals without residues of blasting media. CO2 snow blasting has a minor technical complexity with a possible high degree of automation, but is limited in its cleaning performance. Basic knowledge of CO2 formation must be gained in order to increase the cleaning performance. The basic dependencies of ambient pressure and temperature as well as the possibility of their manipulation regarding the produced CO2 particles were investigated. The investigations were conducted using design of experiments and lead to a model describing the CO2 snow formation and its properties. The goal was to manipulate the properties of the generated CO2 snow in order to optimise the technology regarding the cleaning task.

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Jeong, Ji Hyun, Bong Kyun Kang, Min Su Kim, Hong Seong Sohn, Ahmed A. Busnaina, and Jin Goo Park. "Evaluation of Very Dilute Alkaline Solutions for Wafer Cleaning with Megasonic Irradiation." Solid State Phenomena 195 (December 2012): 181–84. http://dx.doi.org/10.4028/www.scientific.net/ssp.195.181.

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In the semiconductor wafer cleaning, ammonium hydroxide based APM (ammonium peroxide mixture) has been widely used to remove particles and organic contaminants [. However as the film thickness and line width of semiconductor structure scales down rapidly, the material losses by etching reaction of alkaline chemicals can cause serious problem in yield loss due to electric failure. The presence of H2O2 could enhance the material loss on silicon wafer. Very dilute alkaline chemicals might be of interest since it could minimize any possible ionic contamination or chemical residues from chemicals as long as we control the surface roughness and particle removal efficiency. Also the characterization of these very dilute alkaline chemicals will be very useful for particle removal in gas dissolved DI water.

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Ashbrook, Peter C., and Todd A. Houts. "Cleaning out old chemical accumulations." Chemical Health and Safety 6, no. 4 (July 1999): 16. http://dx.doi.org/10.1016/s1074-9098(99)00008-8.

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Gul, Aysegul, Jakub Hruza, and Fatma Yalcinkaya. "Fouling and Chemical Cleaning of Microfiltration Membranes: A Mini-Review." Polymers 13, no. 6 (March 10, 2021): 846. http://dx.doi.org/10.3390/polym13060846.

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Membrane fouling is one of the main drawbacks encountered during the practical application of membrane separation processes. Cleaning of a membrane is important to reduce fouling and improve membrane performance. Accordingly, an effective cleaning method is currently of crucial importance for membrane separation processes in water treatment. To clean the fouling and improve the overall efficiency of membranes, deep research on the cleaning procedures is needed. So far, physical, chemical, or combination techniques have been used for membrane cleaning. In the current work, we critically reviewed the fouling mechanisms affecting factors of fouling such as the size of particle or solute; membrane microstructure; the interactions between membrane, solute, and solvent; and porosity of the membrane and also examined cleaning methods of microfiltration (MF) membranes such as physical cleaning and chemical cleaning. Herein, we mainly focused on the chemical cleaning process. Factors affecting the chemical cleaning performance, including cleaning time, the concentration of chemical cleaning, and temperature of the cleaning process, were discussed in detail. This review is carried out to enable a better understanding of the membrane cleaning process for an effective membrane separation process.

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Brepols, C., K. Drensla, A. Janot, M. Trimborn, and N. Engelhardt. "Strategies for chemical cleaning in large scale membrane bioreactors." Water Science and Technology 57, no. 3 (February 1, 2008): 457–63. http://dx.doi.org/10.2166/wst.2008.112.

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Systematically testing alternative cleaning agents and cleaning procedures on a large scale municipal membrane bioreactor, the Erftverband optimized the cleaning strategies and refined the original cleaning procedures for the hollow fiber membranes in use. A time-consuming, intensive ex-situ membrane cleaning twice a year was initially the regular routine. By introducing the effective means of cleaning in place in use today, which employs several acidic and oxidative/alkaline cleaning steps, intensive membrane cleaning could be delayed for years. An overview and an assessment of various cleaning strategies for large scale plants are given.

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Shaibekov, Daniyarbek, Minbai Zhoroev, Satylganov Artur, Melis Nazaraliev, Talantbek Omurbekov, Yethindra Vityala, and Tugolbai Tagaev. "Chemical burns of the esophagus in children of Kyrgyzstan:10-year analysis of prevalence and cause." Biomedicine 41, no. 2 (July 2, 2021): 233–35. http://dx.doi.org/10.51248/.v41i2.788.

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Introduction and Aim:In Kyrgyzstan, there are still no studies on the prevalence of chemical burns of the esophagus in children, and there are also few studies aimed at studying the causative agents. The present study aimed to assess the prevalence of burns of the esophagus due to the accidental use of various chemicals by children and the chemical composition of cauterizing substances over a 10-year period of admission of children to the clinic. Materials and Methods:An analysis of 1081 cases of chemical burns of the esophagus in children who received inpatient treatment for the period 2011–2020 is presented. Results:In our study, caustic substances were used more often by boys (56.9%) than girls (43.1%), most of the children were under the age of 3 years. There is a tendency for an annual increase in chemical burns of the esophagus. Among the causal factors, there is an increase in the use of alkalis, which are part of the cleaning agents for dishes and plumbing pipes - Krot; recently, the cleaning agent for cauldrons - Aurora is gaining momentum. Conclusion: The emerging situation indicates not only the need for further medical research in this area, but also the tightening of requirements for the packaging and use of household chemicals, and the solution of this problem at the state level.

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Y., Dharshan, Vivek S., Saranya S., Aarthi V.R., and Madhumathi T. "Gesture Control of Robotic Arm." IRA-International Journal of Technology & Engineering (ISSN 2455-4480) 7, no. 1 (May 10, 2017): 1. http://dx.doi.org/10.21013/jte.v7.n1.p1.

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<div><p><em>Robots have become a key technology in various fields. Robotic arms are mostly remote controlled by buttons or panels and sometimes in batch process they are autonomous. The usage of panel boards or control sticks includes a lot of hardwiring and subject to malfunction. It also induces some stress on the operators. Hence major chemical industries like cosmetic manufacturing, paint manufacturing and Biosynthesis laboratory etc., which deals with hazardous environment due to the chemicals and other bio substances, involve humans for the processing. The aim is to reduce the bulk of wiring in the robotic arms and reduce the effort and number of operators in controlling the robotic arm operations. To implement gestures into the process this would be a major breakthrough. This can also be used as pick & place robot, a cleaning robot in chemical industries where a human does not need to directly involved in the process of cleaning the chemicals and also for coating underground tanks.</em></p></div>

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BARRON, WENDY. "Conserving resources ? cleaning chemicals." International Journal of Dairy Technology 40, no. 1 (February 1987): 15–18. http://dx.doi.org/10.1111/j.1471-0307.1987.tb02387.x.

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Lin, Han, Li Juan Wang, Qun Hui Wang, Jin Zheng, and Kenji Sonomoto. "UF Membrane Cleaning Fouled by Food Waste Fermentation." Applied Mechanics and Materials 768 (June 2015): 299–303. http://dx.doi.org/10.4028/www.scientific.net/amm.768.299.

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Flush and chemical cleaning were applied to remove foulants on UF membrane fouled by lactic acid fermentation of food waste. Flushing methods, flushing time and agents for chemical cleaning were studied. The obtained results indicated that backwash at 0.1 MPa for 10s and chemical cleaning with NaClO could gain the best cleaning effect.

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Deierlein, Andrea L., Alexis R. Grayon, Xiaotong Zhu, Yanwen Sun, Xun Liu, Kaelyn Kohlasch, and Cheryl R. Stein. "Personal Care and Household Cleaning Product Use among Pregnant Women and New Mothers during the COVID-19 Pandemic." International Journal of Environmental Research and Public Health 19, no. 9 (May 6, 2022): 5645. http://dx.doi.org/10.3390/ijerph19095645.

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This study examined product use among pregnant women and new mothers in New York City during the COVID-19 pandemic (July 2020–June 2021). Women reported use of personal care and household cleaning products within the previous month, changes in antibacterial product use, receipt of healthcare provider advice, and opinions on environmental chemicals (n = 320). On average, women used 15 personal care products and 7 household cleaning products. Non-Hispanic Black women used nearly two more personal care products; non-Hispanic Black women, those with a college degree, and essential workers used 1–3 more household cleaning products. Compared to non-Hispanic White women, those who were Hispanic or reported their race and ethnicity as Other were two times more likely to use antibacterial personal care products. Non-Hispanic Black, Hispanic, and women who reported their race and ethnicity as Other were 1.5 times more likely to increase antibacterial product use during the pandemic. Nearly all women agreed that environmental chemicals pose health risks and are impossible to avoid, while less than one quarter received advice regarding product use. Product use is a modifiable source of chemical exposures. Results from this study suggest that women may have increased their product use during the pandemic. Healthcare providers may use the current focus on health hygiene to promote discussion and assessment of environmental chemical exposures with patients.

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Babel, S., and S. Takizawa. "A study on membrane fouling due to algal deposition." Water Science and Technology 41, no. 10-11 (May 1, 2000): 327–35. http://dx.doi.org/10.2166/wst.2000.0672.

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Batch filtration experiments in dead-end mode were carried out to investigate the membrane fouling phenomenon due to Chlorella deposition and to analyse the effectiveness of pretreatment techniques to control membrane fouling. Experiments were also conducted to identify efficient and effective physical and chemical methods for cleaning the membrane. For both cellulose acetate and PVDF membranes, the effect of algal concentration was found similar. Initially when the deposition was less, the flux was high and the resistance was very low or negligible. As the deposition increased, the resistance increased exponentially. With further increase in deposition, the resistance increases linearly at a constant rate. Among the three pre-treatment techniques studied, coagulation with alum and ozonation were effective in controlling the fouling of membrane. Chlorine pretreatment was not effective in reducing the algal cake resistance because it brought about an extensive cell lysis. Photographs taken by Scanning Electron Microscope (SEM) showed damage to the cell surface architecture and release of organic matter to the medium after chlorination. Ozone pretreatment was more effective than chlorine in disintegrating only the extracelluar organic matter (EOM) without causing cell lysis, thus bringing down the algal cake resistance. Cleaning experiments after algal filtration without pre-treatment showed that physical cleaning was less effective than chemical cleaning. All four chemicals tested for membrane cleaning could reduce the cake resistance by more than 99%.

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Choi, Hoo Mi, Jang Ah Kim, Yu Jin Cho, Taeh Yun Hwang, Jon Woo Lee, and Tae Sung Kim. "Surface Cleaning of Graphene by CO₂ Cluster." Solid State Phenomena 219 (September 2014): 68–70. http://dx.doi.org/10.4028/www.scientific.net/ssp.219.68.

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Graphene has attracted researchers due to its unique physical properties [1]. However, residues on surface can act as contaminants which further have adverse effects on its performance. As synthetic graphene has inherent surface roughness which can also affect the weak adhesion of layers and leakage points. In order to improve the mechanical and electrical properties, the graphene surface should be uncontaminated. In general practice wet cleaning methods, containing hazardous chemical and solvents are used to remove the residues from graphene surface [2, 3]. To avoid chemicals, mechanical cleaning of graphene using contact mode atomic force microscopy (AFM) has been tried. However, the contact mode AFM cleaning is a limited in cleaning area and the cleaning procedure takes a long time. Recently, CO2 cluster cleaning shows benefits that overcomes these problems. Herein we report the use of CO2 cluster to clean the graphene surface without affecting its inherent properties for the first time. The CO2 cluster treated graphene samples were evaluated by AFM for its roughness change and residual contamination.

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Journal articles on the topic 'Chemical cleanings'

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