Surface activity and cleaning performance of rosin-based quaternary ammonium salt type asymmetric Gemini surfactants

Rosin,a renewable and abundant resource,has been extensively processed and chemically modified to endow it with special properties,especially in the surfactant industry.In this study,four rosin-based quaternary ammonium asymmetric gemini surfactants(RGS-2-n)with different alkyl chain lengths(n=12,14,16,18)were synthesized using a simple two-step method based on dehydroabietylamine as the raw material.The feasibility of these surfactants for cleaning purposes was comprehensively evaluated,suggesting that the surfactants own high surface activity and good cleaning performance.Furthermore,by successfully introducing the amine group of dehydroabietylamine into the hydrophilic group of the surfactants,we avoided its potential harm to the environment and water pollution.Density functional theory proves rosin-based gemini surfactants with asymmetric structure can further improve cleaning efficiency.Overall,our findings suggests that RGS-2-n surfactants are promising and sustainable candidates for cleaning electric plates,and provide new opportunities for rosin application in the electric industry.

Cleaning of two mirrors in the first mirror unit using radiofrequency capacitively coupled plasma

First mirror(FM)cleaning,using radio frequency(RF)plasma,has been proposed to recover FM reflectivity in nuclear fusion reactors such as the International Thermonuclear Experimental Reactor(ITER).To investigate the influence of simultaneous cleaning of two mirrors on mirror cleaning efficiency and uniformity,experiments involving single-mirror cleaning and dual-mirror cleaning were conducted using RF capacitively coupled plasma in the laboratory.For the test and simultaneous cleaning of two mirrors,the FM and second mirror(SM),both measuring 110 mm×80 mm,were placed inside the first mirror unit(FMU).They were composed of 16 mirror samples,each with a dimension of 27.5 mm×20 mm.These mirror samples consist of a titanium-zirconium-molybdenum alloy substrate,a 500 nm Mo intermediate layer and a 30 nm Al_(2)O_(3) surface coating as a proxy for Be impurities.The cleaning of a single first mirror(SFM)and the simultaneous cleaning of the FM and SM(DFM and DSM)lasted for 9 h using Ar plasma at a pressure of 1 Pa.The total reflectivity of mirror samples on the DSM did not fully recover and varied with location,with a self-bias of−140 V.With a self-bias of−300 V,the total reflectivity of mirror samples on the SFM and DFM was fully recovered.The energy dispersive spectrometer results demonstrated that the Al_(2)O_(3) coating had been completely removed from these mirror samples.However,the mass loss of each mirror sample on the SFM and DFM before and after cleaning varied depending on its location,with higher mass loss observed for mirror samples located in the corners and lower loss for those in the center.Compared with SM cleaning,the simultaneous cleaning of two mirrors reduced the difference between the highest and lowest mass loss.Furthermore,this mass loss for the mirror samples of the DFM facing the DSM was increased.This indicated that mirror samples cleaned face to face in the FMU simultaneously could influence each other,highlighting the need for special attention in future studies.

Hole cleaning evaluation and installation spacing optimization of cuttings bed remover in extended-reach drilling

In extended-reach or long-horizontal drilling,cuttings usually deposit at the bottom of the annulus.Once cuttings accumulate to a certain thickness,complex problems such as excessive torque and drag,tubing buckling,and pipe stuck probably occur,which results in a lot of non-productive time and remedial operations.Cuttings bed remover can efficiently destroy deposited cuttings in time through hydraulic and mechanical stirring effects.This paper aims to build a method for hole cleaning evaluation and installation spacing optimization of cuttings bed remover to improve the wellbore cleaning effect.Firstly,a Computational Fluid Dynamics approach with Eulerian—Eulerian multiphase model was utilized to investigate the mechanism of cuttings transportation,and a new type of cuttings bed remover was designed.Next,an evaluation method of hole cleaning effect of remover was established.After that,the effects of several drilling parameters on hole cleaning including flow rate of drilling fluid,rotational speed of drillpipe,rate of penetration,wellbore size,rheological property of drilling fluid,and remover eccentricity on the performance of cuttings bed remover were investigated.The results demonstrate that the new type of remover with streamline blade performs better than conventional removers.The efficiency of hole cleaning is greatly improved by increasing the rotational speed of drillpipe,flow rate of drilling fluid,remover eccentricity,and 6 rpm Fann dial reading for drilling fluid.While higher rate of penetration and large wellbore size result in worse hole cleaning.These findings can serve as an important guide for the structure optimization design of cuttings bed remover and installation spacing of removers.

Investigation of an electrode-driven hydrogen plasma method for in situ cleaning of tin-based contamination

To prolong the service life of optics,the feasibility of in situ cleaning of the multilayer mirror(MLM)of tin and its oxidized contamination was investigated using hydrogen plasma at different power levels.Granular tin-based contamination consisting of micro-and macroparticles was deposited on silicon via physical vapor deposition(PVD).The electrodedriven hydrogen plasma at different power levels was systematically diagnosed using a Langmuir probe and a retarding field ion energy analyzer(RFEA).Moreover,the magnitude of the self-biasing voltage was measured at different power levels,and the peak ion energy was corrected for the difference between the RFEA measurements and the self-biasing voltage(E_(RFEA)-eV_(self)).XPS analysis of O 1s and Sn 3d peaks demonstrated the chemical reduction process after 1 W cleaning.Analysis of surface and cross-section morphology revealed that holes emerged on the upper part of the macroparticles while its bottom remained smooth.Hills and folds appeared on the upper part of the microparticles,confirming the top-down cleaning mode with hydrogen plasma.This study provides an in situ electrode-driven hydrogen plasma etching process for tin-based contamination and will provide meaningful guidance for understanding the chemical mechanism of reduction and etching.

Comparative Study of Structure and Property Changes in Corrosive Media for Self-cleaning Superhydrophobic Magnesium Alloys

Magnesium alloys with superhydrophobicity are constructed by controlling rough surface structure and grafting long hydrophobic alkyl chains. Changes of morphology, phase structure, chemical composition as well as wettability, corrosion resistance of superhydrophobic magnesium alloy upon immersing in corrosive media are investigated comparatively. Meanwhile, the contaminating particles on as-prepared superhydrophobic surfaces can be taken away easily by rolling water droplets. Therefore, the results show that as-prepared superhydrophobic magnesium alloys exhibit enhanced corrosion resistance and self-healing performance. Finally, anti-corrosion and self-cleaning mechanisms are deduced. It can be concluded that it is an effective strategy of preparing superhydrophobic surfaces for improving the corrosion resistance and selfcleaning performance of magnesium alloys.

Wellbore Cleaning Degree and Hydraulic Extension in Shale Oil Horizontal Wells

The efficient development and exploitation of shale oil depends on long-distance horizontal wells. As the degreeof cleaning of the wellbore plays a key role in these processes, in this study, this problem is investigated experimentallyby focusing on the dimensionless cuttings bed height. A method is proposed to calculate the horizontalwellhydraulic extension taking into account the influence of the wellbore cleaning degree on the wellborepressure distribution and assess the effect of a variety of factors such as the bottom hole pressure, the circulatingpressure drop, the drilling pump performance and the formation properties. The analysis shows that the hydraulicextension of horizontal wells decreases with an increase in the cuttings bed height, and the higher the displacementof drilling fluid, the faster the hydraulic extension declines. The annular pressure drop of the horizontalsection increases with the increase of the cuttings bed height, resulting in a higher bottom-hole pressure. Severalarguments are provided to guide the safe drilling of shale oil horizontal wells and overcome the limits of currenttechnological approaches.

A method for cleaning wind power anomaly data by combining image processing with community detection algorithms

Current methodologies for cleaning wind power anomaly data exhibit limited capabilities in identifying abnormal data within extensive datasets and struggle to accommodate the considerable variability and intricacy of wind farm data.Consequently,a method for cleaning wind power anomaly data by combining image processing with community detection algorithms(CWPAD-IPCDA)is proposed.To precisely identify and initially clean anomalous data,wind power curve(WPC)images are converted into graph structures,which employ the Louvain community recognition algorithm and graph-theoretic methods for community detection and segmentation.Furthermore,the mathematical morphology operation(MMO)determines the main part of the initially cleaned wind power curve images and maps them back to the normal wind power points to complete the final cleaning.The CWPAD-IPCDA method was applied to clean datasets from 25 wind turbines(WTs)in two wind farms in northwest China to validate its feasibility.A comparison was conducted using density-based spatial clustering of applications with noise(DBSCAN)algorithm,an improved isolation forest algorithm,and an image-based(IB)algorithm.The experimental results demonstrate that the CWPAD-IPCDA method surpasses the other three algorithms,achieving an approximately 7.23%higher average data cleaning rate.The mean value of the sum of the squared errors(SSE)of the dataset after cleaning is approximately 6.887 lower than that of the other algorithms.Moreover,the mean of overall accuracy,as measured by the F1-score,exceeds that of the other methods by approximately 10.49%;this indicates that the CWPAD-IPCDA method is more conducive to improving the accuracy and reliability of wind power curve modeling and wind farm power forecasting.

Superhydrophobic Micro/Nanostructured Copper Mesh with Self-Cleaning Property for E ective Oil/Water Separation

In this work, a simple method was carried out to successfully fabricate superoleophilic and superhydrophobic N-dodecyltrimethoxysilane@tungsten trioxide coated copper mesh. The as-fabricated copper mesh displayed prominent superoleophilicity and superhydrophobicity with a huge water contact angle about 154.39° and oil contact angle near 0° Moreover, the coated copper mesh showed high separation efficiency approximately 99.3%, and huge water flux about 9962.3 L·h^-1·m-2, which could be used to separate various organic solvents/ water mixtures. Furthermore, the coated copper mesh showed favorable stability that the separation efficiency remained above 90% after 10 separation cycles. Benefiting from the excellent photocatalytic degradation ability of tungsten trioxide, the coated copper mesh possessed the self-cleaning capacity. Therefore, the mesh contaminated with lubricating oil could regain superhydrophobic property, and this property of self-cleaning permitted that the fabricated copper mesh could be repeatedly used for oil and water separation.

Overview of Factors Affecting Dust Deposition on Photovoltaic Cells and Cleaning Methods

Dust deposition on the surface of photovoltaic (PV) cells poses a significant challenge to their efficiency, especially in arid regions characterized by desert and semi-desert conditions. Despite the pronounced impact of dust accumulation, these regions offer optimal solar radiation and minimal cloud cover, making them ideal candidates for widespread PV cell deployment. Various surface cleaning methods exist, each employing distinct approaches. Choosing an appropriate cleaning method requires a comprehensive understanding of the mechanisms involved in both dust deposition on module surfaces and dust adhesion to PV cell surfaces. The mechanisms governing dust deposition and adhesion are complex and multifaceted, influenced by factors such as the nature and properties of the dust particles, environmental climatic conditions, characteristics of protective coatings, and the specific location of the PV installation. These factors exhibit regional variations, necessitating the implementation of diverse cleaning approaches tailored to the unique conditions of each location. The first part of this article explores the factors influencing dust deposition on PV cell surfaces, delving into the intricate interplay of environmental variables and particle characteristics. Subsequently, the second part addresses various cleaning methods, offering an analysis of their respective advantages and disadvantages. By comprehensively examining the factors influencing dust accumulation and evaluating the effectiveness of different cleaning strategies, this article aims to contribute valuable insights to the ongoing efforts to optimize the performance and longevity of photovoltaic systems in diverse geographical contexts.

Self Ear Cleaning: Prevalence and Profile among School Children in Ekiti, Nigeria

Background: Self-cleaning of ears with different objects is a common practice among school children with scanty report in literature. Aim: The aim of this study was to determine the prevalence and profile of self-ear cleaning among school children. Methods: It was a cross-sectional institutional-based study which was carried out among school children in Ekiti, south western Nigeria from January 2017, to March 2017. Results: A total of 174 students participated in this study. Their age ranged between 13 and 17 years. The highest number of participant was found at the age of 15 years. One hundred and eighteen (67.8%) of them had carried out self ear cleaning. Personal hygiene was the commonest reason for self ear cleaning in 28.8% of the students. Cotton buds were mostly used by the respondents in 51.7% of them. Injury to the external auditory canal (EAC) was the most recorded complications. Conclusion: The outcome of this study shows that self-ear cleaning practices were common among school children with a prevalence of 67.8%. Cotton buds were the commonest objects used. Avoidable complications were reported among respondents. There is a need to intensify efforts on public enlightenment programme and the establishment of school health programme in our various schools.

Self-Cleaning Properties of Vanadium Doped TiO₂Sol-Gel Derived Thin Films

In this study, vanadium doped TiO2 thin films were deposited on glass substrates using a sol-gel dip-coating process. X-Ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and UV-Vis spectrophotometer were used to characterize the structural, chemical and the optical properties of the thin films. The photo-catalytic activities of films were investigated by methylene blue degradation. Water contact angle on the film surfaces was measured by a water contact angle analyzer. The results indicated that vanadium doping had a significant effect on the self-cleaning properties of TiO2 thin films.

Self-cleaning Property of Tencel Fabric by Air Plasma and Cross-Linking Treatment Based on TiO_2/SiO_2 Sol-Gel Method

The ionic cross-linking treatment with 3-chloro-2-hydroxypropyl trimethyl ammonium chloride( CHTAC) and 1,2,3,4-butanetetracarboxylic acid( BTCA) was treated on untreated and plasma treated Tencel fabrics,and then TiO_2/SiO_2 sol was applied to the treated samples. Self-cleaning characteristic was investigated using the color measurement spectrophotometer with 7 h UV irradiation. Moreover, the surface morphology, structure change of samples were observed by scanning electron microscopy( SEM) and Fourier transform infrared spectroscopy( FTIR),respectively. The results revealed that with the increase of CHTAC concentration, breaking strength of Tencel fabric increased,whiteness index decreased,and wrinkle recovery angle first dropped and then rose. It was also found that increasing concentration of BTCA,breaking strength of Tencel fabric decreased,whiteness index and wrinkle recovery angle increased. FTIR studies revealed that CHTAC and BTCA had grafted on Tencel fabric. Nevertheless,the molar ratio of 50∶1 of TiO_2/SiO_2 sol endowed Tencel fabric with better self-cleaning properties,compared with sample treated with pure TiO_2. Furthermore,compared with sample treated with TiO_2/SiO_2 sol alone, the combination of plasma and cross-linking treatment( plasma + CHTAC + BTCA + TiO_2/SiO_2) decreased the value of K/S,and increased the value of ΔE,ensured more efficient photodegradation of methylene blue, and thus got a better performance of self-cleaning.

Sociodemographic Characteristics and Prevalence of Self Ear Cleaning in Sokoto Metropolis

Background: Self ear cleaning with cotton buds and other objects is a common practice. Objective: To determine the sociodemographic characteristics and the prevalence of self ear cleaning habit among patients attending a family medicine clinic in a teaching hospital in Sokoto metropolis. Materials and Methods: This was a 4 weeks prospective study carried out between May and June, 2013 at Usmanu Danfodiyo University Teaching Hospital and Specialist Hospital Sokoto. A structured self response questionnaire containing items on sociodemographic characteristics, frequency of administering objects into the ear and complications of self ear cleaning was administered to the respondents after institutional research ethical clearance. The data were analysed using SPSS for windows version 16.0. P-value was considered significantly if less than 0.05. Results: A total of 200 subjects were included in this study, comprising of 93 (46.5%) males and 107 (53.5%) females. Their ages ranged from 18-57 years with the mean age being 30.29 years (±8.70). Eighty percent (160) of the respondents practise self ear cleaning. Types of objects included writing objects and cotton buds. For many of the subjects, the frequency of insertion was once daily and both ears were frequently cleaned. Complications that have arisen due to the practice included otitis externa. Conclusion: Self ear cleaning was prevalent in the subjects. Considering the complications that may arise, ear cleaning is better done by trained health personnel.

A simple way to fabricate an aluminum sheet with superhydrophobic and self-cleaning properties

A superhydrophobic aluminum sheet is fabricated via a hot water immersing process and subsequently surface modification with heptadecafluorodecyltrimethoxy-silane （HTMS）. As revealed by the scan electron microscopy （SEM）, X-ray diffraction （XRD）, and Fourier-transform infrared spectrophotometer （FTIR） results, a rough pseudoboehmite film is formed on the aluminum sheet, and HTMS molecules are grafted on the film surface successfully. These two factors make the treated aluminum sheet present superhydrophobicity with a water contact angle larger than 160° and sliding angle less than 5°, and possess a self-cleaning property. Furthermore, the flexible superhydrophobic aluminum sheet could be pasted to a cylinder surface without destroying its superhydrophobicity. At the end, the effect of hot water treatment time on superhydrophobicity is investigated.

Sol-Gel Preparation of TiO2/SiO2 Nanocomposites and Their Application in Self- cleaning Textiles

The present study involves the preparation of TiO 2/ SiO 2nanocrystals and their application in self-cleaning wool-polyester fabrics.The TiO 2/ SiO 2nanocrystals were successfully synthesized and deposited onto wool-polyester fabrics using the low-temperature sol-gel technique.The as-prepared nanocomposites and the nanocomposites coated samples were characterized by X-ray diffraction( XRD) and scanning electron microscopy( SEM),respectively.The XRD and SEM results showed that the single-phase anatase nanocrystallites were formed and loaded on the fabric surface successfully.The photocatalytic activities of TiO 2-coated and TiO 2/ SiO 2-coated wool-polyester fabrics were measured by studying photodegradation of methylene blue dye.Comparison of the photocatalytic activity of the coated samples reveals superiority of TiO 2/ SiO 2modified sample with respect to that of pure TiO 2modified sample.Our observations indicate that by applying this technique to the fabrics,self-cleaning materials can be designed for practical application.

Self-cleaning performance of a self-cleaning pre-coated steel sheet in an industrial environment

A type of self-cleaning pre-coated steel sheet with excellent self-cleaning performance was developed using hydrophilic surface treatment technology. To understand the self-cleaning properties of this pre-coated steel sheet in an industrial environment, the Jiangjin natural environmental test station was chosen as the outdoor exposure test to be conducted, and the self-cleaning performance of the steel sheet was studied by measuring the water contact angle, stain resistance factor, color difference, and gloss of the steel sheet during the outdoor exposure test. The water contact angle of the self-cleaning steel sheet quickly decreased from 84° to 29° during the outdoor exposure test, and the steel sheet showed excellent hydrophilic properties, which were beneficial to the spread of rain drops and detrimental to the accumulation of the surface pollutants. After an outdoor exposure of 12 months,the self-cleaning steel sheet had a higher stain resistance and cleaner surface than the comparison sample sheet, demonstrating its excellent self-cleaning properties. Moreover, the color difference and gloss rate of the self-cleaning steel ＇sheet were similar to those of the pre-coated steel sheet without hydrophilic surface treatment. Therefore, the hydrophilic surface treatment technology used in this study did not affect the anti-aging property of the self-cleaning steel sheet.

Rendering of Cellulose Acetate Fabrics Self-Cleaning through Treatment with TiO₂Nano Particles

Finishing using TiO2-nanosol treatment of cellulose acetate (CA) fabrics before and after the latter were pretreated with H2O2was undertaken with a view to impart unique properties to CA fabrics, notably, self-cleaning. Finishing was performed as per the pad-dry-cure method. The finishing treatment involved dispersing the nano-sized TiO2particles in a mixture of water and ethylene glycol (1:1) and application of the dispersions to CA fabrics was made under a variety of conditions. Self cleaning ability of the fabrics is favored by 1) increasing the concentration of TiO2-nanosol to certain limit;2) prolongation of curing time up to 15 second;3) raising the microwave power from 80% to 100% but with the certainty that power of 90% is the most proper. Besides, exposure time-to UV radiation-up to 90 minutes is essential to have remarkable self cleaning properties while keeping other technical properties, namely, strength, roughness and wettability practically unaltered. Incorporation of binder in the finishing pad-bath helps stabilizing the deposition of TiO2 with excellent self-cleaning. Pretreatment of CA fabrics with H2O2 is a pre requisite to guarantee excellent self-cleaning ability. Thermofixation and microwave fixation produces fabrics with very comparable technical properties.

A Diamond Electrochemical Cleaning Technique for Organic Contaminants on Silicon Wafer Surfaces

Peroxodiphosphate anion （a powerful oxidant） can be formed in a special water-based cleaning agent through an electrochemical reaction on boron-doped diamond electrodes. This electrochemical reaction was applied during the oxidation,decomposition, and removal of organic contaminations on a silicon wafer surface, and it was used as the first step in the diamond electrochemical cleaning technique （DECT）. The cleaning effects of DECT were compared with the RCA cleaning technique, including the silicon surface chemical composition that was observed with X-ray photoelectron spectroscopy and the morphology observed with atomic force microscopy. The measurement results show that the silicon surface cleaned by DECT has slightly less organic residue and lower micro-roughness,so the new technique is more effective than the RCA cleaning technique.

Technical Regulations on Cleaning Processing of Feeding Millet Seeds in Hebei Province

According to many years of experimental summary, the technical demands, process control, seed test, seed quality and work record （ledger management） of cleaning processing of feeding millet seeds in Hebei Province were studied, and specific measures and technical indicators of the technical regulations were analyzed to provide normalized, standardized, industrial and marketization technical support for the cleaning processing of feeding millet seeds.

Deep cleaning of a metallurgical zinc leaching residue and recovery of valuable metals

Huge quantities of zinc leaching residues(ZLRs) generated from zinc production are dumped continuously around the world and pose a potential environmental threat because of their considerable amounts of entrained heavy metals(mainly lead). Most ZLRs have not been properly treated and the valuable metals in them have not yet been effectively recovered. Herein, the deep cleaning of a ZLR and recovery of valuable metals via a hydrometallurgical route were investigated. The cleaning process consists of two essential stages: acid leaching followed by calcium chloride leaching. The optimum conditions for extracting zinc, copper, and indium by acid leaching were a sulfuric acid concentration of 200 g·L^(-1), a liquid/solid ratio of 4:1(m L/g), a leaching time of 2 h, and a temperature of 90°C. For lead and silver extractions, the optimum conditions were a calcium chloride concentration of 400 g·L^(-1), a pH value of 1.0, a leaching time of 1 h, and a temperature of 30°C. After calcium chloride leaching, silver and lead were extracted out and the lead was finally recovered as electrolytic lead by electrowinning. The anglesite phase, which poses the greatest potential environmental hazard, was removed from the ZLR after deep cleaning, thus reducing the cost of environmental management of ZLRs. The treatment of chlorine and spent electrolyte generated in the process was discussed.