Clean Mechanism Research Articles

Dry cleaning process and mechanism of gas–solid fluidized bed for waste film plastics

Dry cleaning process and mechanism of gas–solid fluidized bed for waste film plastics

Temperature-induced desorption and decomposition of the organic molecule on the fused silica surface: Cleaning mechanism of laser heating

Understanding the structure–property relationships of the organic molecule-fused silica interface at the molecular level provides insights into the nature of their adhesion and desorption. In this study, molecular dynamic simulation and the ReaxFF force field are employed to investigate the adhesion properties of benzene, toluene, dodecane and dibutyl phthalate (DBP) on fused silica at different temperatures. The result shows that adhesion energy between benzene or toluene molecules and fused silica decreases gradually with the increased system temperature. The temperature affects Coulomb and van der Waals forces significantly. Environmental humidity affects the evaporation rate of alkane contaminants from fused silica. Besides, ambient humidity also affects the number of alkane molecules adsorbed to the fused silica surface and the chain configuration of adsorbed alkane molecules. Although the coverage of alkane molecules on fused silica is different, the relationship between temperature and the amount of adsorbed alkane molecules is not affected by the surface coverage of alkane molecules on the fused silica surface. These findings provide theoretical support for removing transparent organic contaminants from glass-like material surfaces using laser heating, laying the theoretical foundation for developing laser cleaning technologies.

Pre-treatment of Remelting Recovery: Ultrasonic Cleaning Mechanism of Non-metallic Layers from Superalloy Scrap Under Based on Hydrochloric Acid and Potassium Iodide Solution System

Pre-treatment of Remelting Recovery: Ultrasonic Cleaning Mechanism of Non-metallic Layers from Superalloy Scrap Under Based on Hydrochloric Acid and Potassium Iodide Solution System

Self-Healable Sandfish Scale-Inspired Scalable Triboelectric Layer for Hybrid Energy Harvesting in Desert Environment.

In deserts, sedimentation from frequent dust activities on solar cells poses a substantial technical challenge, reducing efficiency and necessitating advanced cost-inefficient cleaning mechanisms. Herein, a novel sandfish scale-inspired self-healing fluorinated copolymer-based triboelectric layer is directly incorporated on top of the polysilicon solar cell for sustained hybrid energy harvesting. The transparent biomimetic layer, with distinctive saw-tooth microstructured morphology, exhibits ultra-low sand adhesion and high abrasion-resistant properties, inhibits sedimentation deposition on solar cells, and concurrently harvests kinetic energy from wind-driven sand particles through triboelectric nanogenerator (TENG). The film exhibits a low friction coefficient (0.149), minimal sand adhesion force (27 nN), and a small wear area (327 µm2). In addition, over 2 months, a solar cell with the sandfish scale-inspired structure demonstrates only a 16% decline in maximum power output compared to the bare solar cell, which experiences a 60% decline. Further, the sandfish scale-based TENG device's electrical output is fully restored to its original value after a 6-h self-healing cycle and maintains consistent stable outputs. These results highlight the exceptional advantages of employing biomimetic self-healing materials as robust triboelectric layers, showcasing sustained device stability and durability for prolonged use in harsh desert environments, ultimately contributing to a low cost-of-electricity generation paradigm.

Impact assessment of the residual lifespan of coal-fired power plants on the investment risk of carbon capture and storage retrofit

This research constructs an assessment model for carbon capture and storage (CCS) retrofit of coal-fired power plants (CFPP) by adopting the real option theory. Due to the prohibitive costs associated with retrofitting and insufficient residual lifespan of CFPP, CCS projects may fail to recoup their investment before units are decommissioned. The key contribution of this paper is that it investigates the impact of the residual lifespan of the units on the failure rate of the retrofit investment in addition to the optimal timing of the unit's CCS retrofit. Considering different installed capacities, utilization hours, clean energy subsidy and carbon trading mechanism, this study sets up seven scenarios to assess the impact of different investment environments on the value of project investment. In terms of sensitivity analysis, the residual lifespan of the unit, its interaction with carbon price, carbon price volatility, technological advancement rate, and subsidy level are examined for their impacts on the project investment risk. The findings suggest that the critical period for determining the long-term success of most coal-fired unit retrofits may be present, and more supportive policies need to be examined to facilitate the green transformation and upgrading of coal-fired units.

Research on Laser Cleaning Technology for Aircraft Skin Surface Paint Layer.

In this study, a pulsed laser operating at a wavelength of 1064 nm and with a pulse width of 100 ns was utilized for the removal of paint from the surface of a 2024 aluminum alloy. The experimental investigation was conducted to analyze the influence of laser parameters on the efficacy of paint layer removal from the aircraft skin's surface and the subsequent evolution in the microstructure of the laser-treated aluminum alloy substrate. The mechanism underlying laser cleaning was explored through simulation. The findings revealed that power density and scanning speed significantly affected the quality of cleaning. Notably, there were discernible damage thresholds and optimal cleaning parameters in repetitive frequency, with a power density of 178.25 MW/cm2, scanning speed of 500 mm/s, and repetitive frequency of 40 kHz identified as the primary optimal settings for achieving the desired cleaning effect. Thermal ablation and thermal vibration were identified as the principal mechanisms of cleaning. Moreover, laser processing induced surface dislocations and concentrated stress, accompanied by grain refinement, on the aluminum substrate.

Review on Design and Fabrication of Solar Panel Cleaning Mechanism

Today energy demands are increasing sharply therefore as a Renewable source of power, solar energy has an important role in producing the electricity direct from sunlight. The surface of solar panel in solar power plants becomes dirty due to natural factors such as dust and bird droppings. This project aims at increasing the efficiency of solar power plants by solving the problem of accumulation of dust on the surface of solar panel which leads to reduction in plant output and overall plant efficiency. It proposes to develop a Solar Panel Cleaning System which could remove the accumulated dust on its surface on a regular basis and maintain the solar power plant output.[8]

Saffron corm sorting and rot treatment strategy for productivity enhancement for precision agriculture

One of the most economical and precious spices ever known is saffron. It has innumerable pharmaceutical applications, and its cultivation is limited to certain topographic regions throughout the world. Although efforts are continuously being made to increase productivity and increase the area under cultivation, there are multiple factors leading to its low production. Corm size is one of the major factors affecting the quality and production of saffron. The more the corm size for a plantation, the better the yield of the crop. This can pose a serious threat to saffron cultivators who are not able to get good quality corms and sort quality corms from infected ones. Additional factors affecting saffron cultivation include attack by fungus leading to corm rots and sclerotineal disease. In this paper, IoT (Internet of Things) has been used to provide an energy-efficient, ready-to-use, reliable, and user-friendly solution for corm sorting and treatment before sowing to promote quality, better yield and minimized wastage due to corm rots. After sorting the corms, they are treated with 0.2% of tiabendazole fungicide solution and dried, before sowing and for long-term storage. Firstly, sorting and treatment system for the saffron corms processing as per weight is proposed. First two-layer cleaning mechanism to remove foreign substances, then three-step treatment has been applied to remove microorganisms. An automated conveyor system equipped with IoT devices was used for sorting and treating saffron corms. Different energy efficient LPWA (Low Power Wide Area) and LTE (Long Term Evolution) technologies used in the framework, for communication are NB-IoT (Narrow Band IoT) and LoRa (Long Range Radio).

Performance Analysis of Semi-Automatic Solar Panel Cleaning System

Solar energy has been one of the most promising energy sources since the 1990s. However, the efficiency of solar panels is reduced due to dust accumulation over modules, which blocks the incident light from the sun. The efficiency of a solar panel depends on various factors, such as the quality of the solar cells, the design of the panel, the temperature and intensity of the sunlight, and the presence of any shading or obstructions. High-efficiency solar panels can produce more electricity from the same amount of sunlight, resulting in higher energy production and cost savings over the system’s lifetime. The study used a semi-automatic cleaning mechanism, which is one of the recent developments made on automated cleaning systems of solar photovoltaic modules. Aims of this study is to improve the efficiency of solar panels by designing and implementing a semi-automatic dust-cleaning mechanism. This study found that the experimental model shows improved efficiency by about 7 percent. The study’s findings are consistent with previous research that emphasizes the importance of regular cleaning of solar panels to improve their efficiency and reliability. This research has important implications for improving the efficiency and reliability of solar energy systems. Solar panel owners can improve the profitability and sustainability of their system, leading to more widespread adoption of solar energy by optimizing the cleaning process and reducing maintenance costs.

Washing performance of microbubbles on porous media

The backwashing effect of filter materials in oilfield wastewater treatment processes is essential for the efficient long-cycle operation of equipment and the reduction of hazardous waste. Recently, there has been growing interest in microbubble cleaning technology due to its exceptional cleaning efficiency for porous particles. However, the mechanism of microbubble-pore interaction and its corresponding cleaning effects remain unclear. This study investigated the performance of microbubbles in removing petroleum hydrocarbon pollutants from walnut shells, comparing them with traditional water washing and state-of-the-art ultrasound methods. Microbubble cleaning proved most efficient in removing low-viscosity petroleum hydrocarbons, followed by ultrasonic waves, both of which showed significantly higher efficacy compared to traditional water washing. When treating petroleum hydrocarbon pollutants with high viscosity, microbubble cleaning was more effective than clear water but slightly less effective than the ultrasonic wave method. Based on the analysis of clogging phenomena observed via scanning electron microscopy (SEM), the mechanism of microbubble cleaning within porous media was unveiled. Microbubbles were found to be proficient at dislodging contaminants adsorbed within secondary pores through collision and the force generated by liquid jets, as well as penetrating the small pores to eliminate pollutants from these inner spaces. Finally, an economic cost analysis of the various cleaning methods revealed that the microbubble approach is a cost-effective choice for the removal of light oil or the situations where a relatively lower removal efficiency for heavier oils is acceptable.

An ecofriendly and sustainable method for efficient cleaning of raw cashmere fiber with enzymes in SCF-CO2

An efficient and ecofriendly method to remove impurities from raw cashmere fiber was constructed by employing various biological enzymes (lipase, cellulase, pectinase and protease) to form reverse microemulsion in supercritical carbon dioxide. An investigation and optimization of various parameters, such as the dosage of biological enzymes, cleaning temperature, pressure and duration for this method were performed according to the whiteness and weight loss of the treated samples. Then the proposed method was further validated by energy dispersive X-ray spectrometry (EDS), scanning electron microscopy (SEM) analysis to verify the impurity removal from cashmere fiber. Moreover, the aggregation structure and properties of cleaned cashmere fiber were also investigated by X-ray powder diffraction (XRD), strength measurement, moisture absorption testing and thermal analysis (TG-DTG). The results declare that, via forming a type of (W+enzymes)/SCF-CO2 microemulsion to transfer the biological enzymes into supercritical medium, various impurities from raw cashmere fiber could be efficiently decreased and removed, which cleaning performance was better than a conventional control process. The cleaning efficiency for various impurities was notably influenced by the dosages of the applied enzymes and system parameters, which could be improved at an appropriate condition in SCF-CO2. Furthermore, the cleaning feasibility, reliability and efficiency of the enzymatically catalyzed method for raw cashmere fiber was successfully verified by SEM, EDS, XRD, TG-DTG, tensile strength analysis, and a supercritical cleaning mechanism for raw cashmere was further proposed.

Light Meson Decays at BESIII

The 10 billion J/ψ decays collected with the BESIII experiment offer a unique opportunity to investigate the decays of η and η′ mesons produced in the radiative J/ψ → γη(′) transitions. Using this clean production mechanism, the BESIII experiment is making important contributions to precision studies of the strong and electromagnetic interactions in η(′) decays. Three papers are presented in which the decays η → π+π−π0, η → π0π0π0, η′ → ηπ0π0π0, and η′ → π+π−e+e− are studied to test C and CP symmetry, as well as the predictions of different effective field theories.

IMPROVEMENT OF THE CLEANING SYSTEM OF OIL GAS FLOWS USING AN AERODYNAMIC INSERT

Air pollution is becoming a problem due to inefficient technological processes that accompany the mechanical processing of solid materials in various industries, including metalworking and woodworking, coal enrichment, coal burning in thermal power plants, metallurgy and construction materials industries. The problem is relevant for cement factories, since some of them use outdated equipment. Fine dust in this context becomes particularly important because the particle size of this dust affects the quality and grade of the concrete produced. Given the specifics of cement production and the goals of our research, which are to effectively collect small particles, it is important to note that wet cement production methods are not the best solution. The ideal solution for the problem of cleaning dust and gas flows in the cement industry is the use of a two-stage dust collection system, which combines an advanced cyclone and a bag filter. The system's periodic shaking mechanism allows for effective capture and control of fine dust particles, ensuring high quality cement production and reducing environmental impact. The combination of a cyclone, an acoustic coalescer and a block of bag filters, which is equipped with a periodic cleaning mechanism, as well as the addition of a system for collecting fine dust using a collector funnel, will split the collected dust into two fractions: fine (a = 10−5 to 10−7m) and coarse (a > 10-4m). The first fraction can be used to produce high-quality cement of high cost in the cement industry. The second fraction returns to the main technological process at its finishing stage.

Environmentally friendly photothermal reconstruction of cement/asphalt road: Can road markings also be cleaned in such unexpected ways?

This paper innovatively proposes a new method for safe and environmentally friendly road markings removal, using nanosecond pulsed lasers to clean the standard yellow, white, red, and black cold spray markings of cement concrete road and asphalt concrete roads by dry cleaning and wet (liquid-assisted) cleaning. The optimal cleaning process for road markings was explored by changing the laser's energy density and spot overlap ratio. The markings' dry and wet dynamic stripping behavior and removal mechanism was analyzed by combining morphology characterization, EDS analysis, XRD analysis, infrared spectroscopy, infrared images, and a high-speed camera. In the complete cleaning state, markings is entirely removed without damage to the road. Dry laser cleaning can meet the cleaning needs of cement roads, and wet laser cleaning can meet the cleaning needs of asphalt roads. The dry laser cleaning mechanism for yellow and white markings is evaporation and phase explosion caused by thermal ablation, the dry laser cleaning mechanism for red markings is thermal stress vibration, and the dry laser cleaning mechanism for black markings is mainly evaporation caused by ablation. The wet laser cleaning mechanism of each color marking is that the rapid growth of steam bubbles in the superheated liquid provokes the explosive evaporation of the liquid film layer. Laser cleaning can slightly increase cement/asphalt concrete road roughness and enhance anti-slip performance.

Effects of two mild amino acids on benzotriazole residue desorption during cobalt post-chemical mechanical polishing cleaning: Experimental and theoretical studies

During the polishing process of the cobalt (Co) interconnect layer, the corrosion inhibitor in the polishing solution will leave an organic residue on the polished cobalt surface, which needs to be removed by the post-chemical mechanical polishing (CMP) cleaning process. However, given the active chemical properties of cobalt, the potent and corrosive complexing agents in traditional cleaning solutions have the drawback of generating new corrosion defects on the cobalt surface. In this study, an eco-friendly cleaning solution is developed utilizing tetraethyl ammonium hydroxide (TEAH), deionized water, and either sarcosine or serine, thereby ensuring the absence of any additional introduction of metal impurities. The removal effect of the cleaning solution on BTA was tested using atomic force microscopy (AFM) and X-ray photoelectron spectrometer (XPS). The results demonstrate that post-CMP cleaning with either sarcosine or serine yielded a cobalt surface with reduced roughness (2.78 nm and 2.63 nm), diminished Co-BTA content (10.6% and 9.5%), and a lowered contact angle (44.3° and 37.9°). To elucidate the mechanism of post-CMP cleaning, electrochemical measurements and molecular dynamics were employed. Initially, in the cleaning solution with a pH of 10.4, the adsorption of BTA and cobalt is minimized. Subsequently, as serine permeates through the BTA residue layer, the desorption of BTA is expedited through competitive adsorption. These findings contribute valuable insights into the mechanism of residue removal in post-CMP cleaning processes.

Process and mechanism of paint stripping on CFRP by UV nanosecond laser

Laser cleaning shows exciting promise for removing paint from aircraft skins. This paper focuses on the application of a 355 nm (UV) nanosecond pulsed laser for paint removal from aircraft skin composites. First, the effects of process parameters on laser paint removal are analyzed, and mapping relationships between these parameters and the depth and roughness of paint removal are established. After that, the micromorphology and dynamic behavior of the samples are observed and characterized with the help of SEM, EDS and high-speed photography. Finally, the paint cleaning mechanism and damage mechanism of the 355 nm laser are discussed. The results show that the removal of paint is a combined result of photothermal and photochemical effects, while the damage of carbon fiber is caused by thermo-mechanical forces. When the laser repetition frequency is 50 kHz, the scanning speed is 1100 mm/s, and three cleanings are performed, the paint on the CFRP surface can be completely removed while maintaining the integrity of the carbon fiber.

The Impact of Family Life Cycle on Farmers’ Living Clean Energy Adoption Behavior—Based on 1382 Farmer Survey Data in Jiangxi Province

Encouraging farmers to adopt greener and cleaner energy is crucial for reducing energy pollution and achieving carbon neutrality goals. In rural China, the decision making of farmers is often closely related to the whole family. At different stages of the family life cycle, the family has different characteristics, which leads to heterogeneity in the focus and final decision of farmers in adopting living clean energy. Therefore, this paper studies the farmers’ living clean energy adoption behavior from the perspective of the family life cycle. It is helpful to identify the different policy needs and the evolution of farmers in different stages in order to provide a reference and inspiration for encouraging the adoption of living clean energy by farmers and for promoting the development of clean energy in rural areas. Based on the survey data of 1382 farmers in Jiangxi Province, this paper uses a multiple linear regression model to explore the impact of the family life cycle on farmers’ clean energy adoption behavior. The results show the following: (1) The family life cycle has a significant impact on farmers’ living clean energy adoption behavior, which is reflected in four aspects: energy demand, livelihood strategy, health demand and support burden; (2) Awareness of environmental ecology and frequency of government promotion have significant positive effects on farmers’ living clean energy adoption behavior, while gender has significant negative effects on farmers’ clean energy adoption behavior; (3) There are also differences in the influencing factors of farmers’ living clean energy adoption behavior at different stages of the family life cycle. Therefore, when promoting clean energy in rural areas, a precise clean energy incentive mechanism should be adopted to treat families in different family life cycle stages differently.

Investigation of sodium bicarbonate media blasting technology for achieving the cleaner production of graphite deposition reactor cleaning process: Process optimization and simulation

The periodic cleaning of silicon nitride residues on the graphite deposition reactor surface is a critical process for producing silicon wafers in the photovoltaic manufacturing industry. A green, non-erosive and sustainable sodium bicarbonate media blasting technology (SBMBT) was investigated in this research, aiming for providing an alternative to the widely-used polluting liquid hydrofluoric acid soaking method in the industry. By comparing the cleaning behavior of different blasting media (sodium bicarbonate, alumina, glass bead and walnut shell) under various blasting angles and pressures, the most appropriate cleaning process parameters (30° and 0.3 MPa) and efficient removal rate (0.085 cm2/s) of SBMBT were determined based on the statistical characterization of surface roughness data. Under the most appropriate cleaning process parameters, the mean value of roughness (Ra = 2.119 μm) and cleanliness of graphite deposition reactor surface that was cleaned by SBMBT could meet industry standards. Based on the stress sample data provided by the six identical simulations on each of the nine parameter combinations, the multiple-impact cleaning mechanism of SBMBT was revealed using the LSTC dynamics (LS-DYNA) particle impact model and a high-speed camera. Based on five sets of the recovery experiments data, the mean value of blasting media recovery rate obtained in the validation of the designed sodium bicarbonate media recovery scheme was 79.98%, and the consistency of the media crystal form before and after recovery was confirmed by PXRD. As the experimental results indicate, SBMBT is a green technology with low damage, no residue, and can effectively alleviate the problem of solid waste treatment, which is worthy of being applied in graphite deposition reactor cleaning processes.

Effect of double-layer filter cartridge with an inner cone on the pulse-jet cleaning performance of cartridge dust collectors

The double-layer filter cartridge with an inner cone was designed to improve the pulse-jet cleaning performance of the filter cartridge. The flow field and pressure variation of the double-layer filter cartridge were investigated with the help of numerical simulations. The pressure at the inner wall of the filter cartridge was explored by varying three parameters: the height of the cone (h), the diameter of the cone (D) and the distance between the top of the inner cone and the baffle (H). The results showed that for conventional filter cartridge, influenced by the angle of the pulse-jet, the airflow got sufficiently expanded after the pulse-jet airflow reached the middle of the filter cartridge, and the pressure at the top of the filter cartridge was slight. It was found that the cone diameter and the distance between the top of the inner cone and the baffle had a significant effect on the pressure of the inner wall of filter cartridges, with the distance between the top of the inner cone and the baffle had the most excellent effect and the height of the cone had the slightest effect. Compared with conventional filter cartridges, the peak pressure at measurement point O1 of the optimized double-layer filter cartridge (h = 120 mm, D = 160 mm, H = 0 mm) was increased by 543.3%. The coefficient of variation (C.V.) of the pressure at the inner wall of the outer filter cartridge was significantly reduced, indicating that the pulse-jet cleaning effect of the optimized double-layer filter cartridge was significantly improved. This study can provide theoretical support to reveal the mechanism of pulse-jet cleaning of double-layer filter cartridges and technical support to optimize the design of double-layer filter cartridges.

De-oiling characteristics and mechanism of oil-bearing sludge cleaned by CGAs

There hasn't been much study on using Colloidal Gas Aphrons (CGAs) to clean oily sludge. In addition, the efficacy and mechanism of CGAs-enhanced surfactant cleaning of oily sludge are not yet clear. Therefore, in this study, CGAs prepared from the compound surfactant solution were used to clean oily sludge in an oil field in Xinjiang. The performance of CGAs in terms of oil removal and particle size was both examined when building the surfactant compounding system. The removal abilities of CGAs from different crude oil components and an analysis of the chemical cleaning process of CGAs were studied. The results demonstrated that the interfacial tension was as low as 3.535 mN/m and the oil removal rate of CGAs was as high as 92.9% when the ideal ratio of sophorolipid (SL) to sodium dodecyl benzene sulfonate (SDBS) was 6: 4. The average particle size of CGAs was 90.57 µm at this ideal ratio. The Zeta potential and turbidity of the supernatant after CGAs cleaning was lower than those of chemical cleaning. Infrared analysis, two-dimensional fluorescence analysis, and thermogravimetric methods were used to characterize the oily sludge after CGAs cleaned. According to the analysis's findings, CGAs' enormous specific surface area allows them to adsorb more petroleum pollutants and improved the ability of those pollutants to migrate between the water phase and other phases of the atmosphere. Also, CGAs are particularly successful in adhering to petroleum-based pollutants in oil sludge for the removal of light constituents like n-alkanes and aromatic hydrocarbons due to the synergistic effects of hydrophobic and electrostatic effects on the functional surface of CGAs. This work provides useful information on the mechanism of the enhanced removal of crude oil from oily sludge by CGAs and provides a new idea for oily sludge cleaning.