Cleaning Process Research Articles

Role of Higgs and Leggett modes for the third harmonic response in noncentrosymmetric superconductors

The amplitude and phase of the third harmonic response in superconductors provide important insights into collective Higgs and Leggett modes, respectively, in the superconducting state. In particular, for twice the incident frequency equal to the binding energy (2ω=2Δ), one finds a resonance of the amplitude and a corresponding phase jump in the third harmonic response, respectively. We generalize these concepts to superconductors without an inversion symmetry, which can be effectively described by a two-band model with an order parameter consisting of spin-singlet (even parity) and spin-triplet (odd parity) components. In our work we use an effective action approach for the derivation of the nonlinear response and assign the underlying physical processes to their respective Feynman diagrams. We calculate the third harmonic signal exemplary for the noncentrosymmetric compound CePt3Si, showing that it contains contributions from three distinguishable sources, namely the Higgs mode, the Leggett mode, and quasiparticles (broken Cooper-pairs). Only in the clean limit diamagnetic Raman-like processes contribute to the third harmonic signal, whereas the quasiparticle contributions dominate the collective modes for all triplet-singlet ratios of the gap structure. In the dirty limit, we find a significant enhancement of the Higgs mode contributions to the third harmonic response, due to the inclusion of nonvanishing paramagnetic diagrams. Finally, we argue that the phase difference between the third harmonic and the fundamental signal might reveal a jump, where its size is dependent on the light-matter coupling. Published by the American Physical Society 2024

Multi-Technique Assessment of Chelators-Loaded PVA-Borax Gel-like Systems Performance in Cleaning of Stone Contaminated with Copper Corrosion Products.

Currently, one of the most important challenges for the conservation of stone artworks is the removal of metal corrosion products on their surfaces. Traditional cleaning methods, which typically involve the application of aqueous solutions containing chelating agents capable of complexing these metal ions, have shown some weaknesses. These weaknesses become apparent when such methods are applied to statues and other vertical surfaces or when aiming to limit the cleaning process to a specific area with controlled application times. Furthermore, the porosity of the stone surface plays a role concerning the cleaning efficiency. To address these issues, chelating agents can be incorporated into gel-like materials. This study is a proof of concept to evaluate the cleaning efficacy of various gel formulations composed of polyvinyl alcohol (PVA), borax (B), and agarose (AG), loaded with two chelators: ethylenediaminetetraacetic acid (EDTA) and potassium sodium tartrate (PST or Rochelle salt). Three types of carbonate stones (travertine, Lecce stone, and Carrara marble) characterized by different porosities were artificially stained with copper sulphates and treated with the different PVA-B-AG formulations. The effectiveness of the treatment was directly monitored on the stones using a multi-technique approach that included scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS) and non-invasive portable nuclear magnetic resonance (NMR). Additionally, the rheological properties of the gels were investigated, and the Fourier transform infrared attenuated total reflection spectroscopy (FTIR ATR) was used to analyse the chemical structure of the gel before and after treatment, aiming to understand the changes induced by the cleaning process.

Tritium Release During Different Decommissioning Techniques

In the field of decommissioning and decontamination, multiple difficulties arise. The main issues in tritium decontamination are due to its ability to permeate through virtually any material. As a result, the release of tritium from contaminated materials is affected by multiple parameters, complicating the exact characterization and choice of the decontamination strategy. Research efforts by the decontamination and clean-up processes group at SCK•CEN are currently concentrating on two different projects. In the first project, the dismantling of an obsolete tritium installation is evaluated. Parts of this installation have tritium inventories in the MBq/g range. Tritium release using several cutting techniques and the tritium inventory of the resulting cut parts and secondary materials, such as sawdust and cutting curls, is investigated. The second project concerns the detritiation and safe conversion of tritiated NaK into less reactive carbonates.

Materials and clean processes for sustainable energy and environmental applications: Foreword

Materials and clean processes for sustainable energy and environmental applications: Foreword

Greenhouse gas emissions and carbon and water footprints during processing of Lei bamboo shoots

Lei bamboo shoots are extensively used in the food processing industry, producing solid waste such as bamboo shoot shells and liquid wastewater. This study analyzed several sewage indicators, revealing that the majority exceed the national standards of China for direct water discharge. A field experiment was conducted over a period of 4 months to evaluate the effects of different treatments during the natural decomposition of bamboo shoot shells.The treatment groups consisted of the boiled experimental group (EG) and the control group (CG). Results showed that in EG, the methane emission increased by 8.6% (P < 0.05), the carbon dioxide emission increased significantly by 19.7% (P < 0.01), and the nitrous oxide emission decreased by 37.9% (P < 0.01) relative to those in CG. Regression analysis was employed to establish a relationship model between CH4, CO2, and N2O emission fluxes and temperature and humidity in the EG and CG groups. A specific functional relationship was identified between CH4 and CO2 emission fluxes and temperature and humidity, but N2O emission was present. No significant correlation was found between flux and ambient temperature and humidity (R2 < 0.3). We also estimated that the carbon dioxide emissions and water consumption of producing 1 kg of canned bamboo shoots were 2.8669 kg and 86.8 L, covering the processes in the life cycle of bamboo shoot products. This study identifies the potential water pollution problems and provides insights into resource utilization and recycling in bamboo shoot food processing, facilitating the realization of clean production processes. It also sheds light on the water footprint of bamboo shoot products throughout their life cycle, and the carbon footprint research provides valuable references.

Adsorptive and oxidative removal of phenolphthalein by sono-assisted synthesized FeAcC in advanced oxidation-integrated fluidized bed reactor

ABSTRACT Environmental water sources are under increasing threat due to the addition of harmful chemicals not addressed by conventional water treatment processes. To work on this concern, the current study aimed to synthesize sono-assisted Fe-modified activated carbon-chitosan (FeAcC) composite and construct a laboratory-scale ozone-integrated fluidized bed reactor (FBR) to eliminate phenolphthalein (php). Following 120 min of incubation, the adsorbent demonstrated a 27.28 mg g−1 of php adsorption capacity at pH 4 with 0.5 g L−1 of adsorbent dosage. The adsorption efficacy and mechanism were defined using isotherm and kinetic models. The study investigated the impact of different factors including, initial concentration, reuse of FeAcC, recirculation flow rate, and hydraulic retention time (HRT), on the efficiency of php removal. The optimum removal efficiency was observed at approximately 95% after 20 min of operation at 1.5 L min−1 recirculation flow rate (batch FBR) and 70 min of HRT (continuous FBR) under 400 mg h−1 ozonation rate. Experimental parameters were optimized using response surface methodology (RSM) with central composite design (CCD) to improve php removal. The large-scale implementation of the findings in the future can be a step for adding new technology for clean water treatment processes for emerging toxic pollutants.

Solar Panel Dirt Detection and Cleaning System

The proposed solar panel dirt detection and cleaning system improves the efficiency in generating output voltage that integrates Arduino micro-controller with voltage recognition technology to enhance the efficiency of solar energy harvesting. The system utilizes voltage divider circuit to identify dirt or debris on the solar panel surface by analyzing changes in output voltage produced by the solar panel. Along with voltage divider circuit, LDR (Light Dependent Resistor) sensor is utilized to enable the cleaning process only in day time when the intensity level of the LDR is more than threshold value. Upon detection, the Arduino micro-controller triggers a cleaning mechanism to remove the identified dirt. The cleaning mechanism can be designed using actuators, brushes and other appropriate tools. The Arduino's programmability allows for customization of cleaning intervals, ensuring timely maintenance.

Development and optimization of large-scale integration of 2D material in memristors

Two-dimensional (2D) materials like transition metal dichalcogenides (TMD) have proved to be serious candidates to replace silicon in several technologies with enhanced performances. In this respect, the two remaining challenges are the wafer scale growth of TMDs and their integration into operational devices using clean room compatible processes. In this work, two different CMOS-compatible protocols are developed for the fabrication of MoS2-based memristors, and the resulting performances are compared. The quality of MoS2 at each stage of the process is characterized by Raman spectroscopy and x-ray photoemission spectroscopy. In the first protocol, the structure of MoS2 is preserved during transfer and patterning processes. However, a polymer layer with a minimum thickness of 3 nm remains at the surface of MoS2 limiting the electrical switching performances. In the second protocol, the contamination layer is completely removed resulting in improved electrical switching performances and reproducibility. Based on physico-chemical and electrical results, the switching mechanism is discussed in terms of conduction through grain boundaries.

Surface Cleaning of Oil Contaminants Using Bulk Nanobubbles.

The removal of oil from solid surfaces, such as textiles and plates, remains a challenge due to the strong binding affinity of the oil. Conventional methods for surface cleaning often require surfactants and mechanical abrasion to enhance the cleaning process. However, in excess, these can pose adverse effects on the environment and to the material. This study investigated how bulk nanobubble water can clean oil microdroplets deposited on surfaces like glass coverslips and dishes. Microscopy imaging and further image analysis clearly revealed that these microdroplets detached from both hydrophobic and hydrophilic surfaces when washed with bulk nanobubble water within a fluidic microchannel. Oil contaminant cleaning was also conducted in water as mobile phase to mimic the circumstances that occur in a dishwasher and washing machine. Cleaning on a larger scale also proved very successful in the removal of oil from a porcelain bowl. These results indicate that nanobubble water can easily remove oil contaminants from glass and porcelain surfaces without the assistance of surfactants. This is in stark contrast to negligible results obtained with a control solution without nanobubbles. This study indicates that nanobubble technology is an innovative, low-cost, eco-friendly approach for oil removal, demonstrating its potential for broad practical applications.

Exploration and practice of cleaner production of titanium dioxide by sulfuric acid process

In China, titanium dioxide production is still based on sulfuric acid process which suffers from high energy consumption, serious pollution and long process. For solves the traditional problems, cleaner production is an effective way for the high-quality development and comprehensive green transformation of sulfate titanium dioxide industry. Taking a titanium dioxide company in Panzhihua as an example, this paper expounds the exploration and practice of utilizing advanced process equipment to transform the original specific process and improve the clean production process and equipment. The company has upgraded the continuous acidolysis process, VCE (Vapor-Condense-Evaporate) crystallization process and MVR (Mechanical Vapor Recompression) concentration process for the three core sections with serious waste and energy consumption, and effectively coupled with the other original sections. Through the analysis of production operation, the new process significantly improves the comprehensive resources utilization efficiency of titanium, sulfur and iron, improves the working environment of labors, and reduces the energy consumption, the amount of three wastes and the production cost. Company in the gradual realization of cleaner production, made beneficial exploration.

Chronic exposure to drinking water nitrate and trihalomethanes in the French CONSTANCES cohort

Trihalomethanes (THMs) and nitrate are widespread chemicals in drinking water. Chronic exposure has been associated with increased cancer risk despite inconclusive evidence, partly due to the challenges in long-term exposure assessment and potential exposure misclassification.We estimated concentrations of nitrate and THMs in drinking water using a public regulatory monitoring database (SISE-Eaux) for CONSTANCES, a French population-based prospective cohort.We obtained 26,322,366 measurements of drinking water parameters from 2000 to 2020. We excluded missing, implausible and duplicated measurements; we corrected or imputed missing geocodes of sampling locations; we calculated the annual median concentration of nitrate and THMs by surveillance area. To predict missing annual median concentrations, linear mixed models with random intercept using surveillance area as a clustering variable were developed for each region for nitrate and the four THM components (chloroform, chlorodibromomethane, bromodichloromethane and bromoform) separately. Concentrations in the nearest surveillance area from the household were merged per year among 75,462 participants with residential history geocoded for 2000–2020. Estimated concentrations resulting from this approach were compared with measured concentrations in 100 samples collected in Paris, Rennes and Saint-Brieuc in 2021.Median annual concentrations of total THMs and nitrate at study participants’ homes for 2000–2020 were, respectively, 15.7 μg/l (IQR: 15.2) and 15.2 mg/l (IQR: 20.8). Among these, 35% were based on measurements for nitrate (16% for THMs), 44% (46%) were predicted using on linear mixed models, and 21% (38%) were based on distribution unit median values. Conditional R2 predictive models ranged from 0.71 to 0.91 (median: 0.85) for nitrate, and from 0.48 to 0.80 for THMs (median: 0.68).These concentrations will allow future association analyses with risk of breast and colorectal cancer. Our cleaning process introduced here could be adapted to other large drinking water monitoring data.

Performance of steel protective structure for historical masonry aqueducts against rockfall: Numerical and field studies

This study investigates the design and impact performance of novel steel protection system intended to safeguard historical masonry aqueducts from damage caused by hazardous rocks. The historical aqueduct under consideration is located on the Sumela Monastery campus. To achieve this, we developed a three-dimensional (3D) photogrammetric model of the study area and identified all risky blocks along with their real positions. Subsequently, we conducted 3200 probabilistic rockfall analyses in eight critical trajectories with four different rock sizes to calculate the velocity, kinetic energy, and run-out distance of fallen blocks. In the second part of the study, finite element models of the steel protective structure were created using Abaqus software. A nonlinear dynamic impact analysis method was applied to analyze nine rockfall scenarios with two different geometries and four different sizes. Based on the rockfall and impact analyses, sections of the protection structure were designed using plastic design criteria. The steel protection structure for aqueducts demonstrated high effectiveness against rockfall, with a risk index (Ir) ranging from 0.93 to 1.00 (except for the upper end of the column–beam connection impacts). Even in these scenarios, the structure provided protection by reducing rock energy and altering its trajectory. In the third part, a steel structure was constructed in the field, and a rock cleaning process was carried out. During rock cleaning, punctures occurred while breaking sharp rocks. To mitigate this risk, a parametric study was conducted using a steel angle stopper. The proposed simple steel angle stopper effectively reduced rockfall damage to historical structures by blocking rock passages and rapidly reducing kinetic energy. Ultimately, during the removal of 5000 m³ of hazardous rocks, no damage was inflicted on the historical structure. The protection system showed a near 100 % success rate in safeguarding the aqueduct. This temporary structure can be employed to protect historical structures from rockfall hazards.

A clean metallurgical process for vanadium precipitation from vanadium-rich solutions

Ammonium salt vanadium precipitation process has excellent performance in industrial production, but its shortcomings such as high cost and environmental impact are not conducive to sustainable development. In this paper, ethylenediamine was selected as the precipitant, and vanadate was precipitated from acidic simulated vanadium-rich solutions by the ammonium salt precipitation process. The high purity V2O5 product was obtained after calcination. Under optimal conditions, the precipitation rate of vanadium reached 94.8 %, and the purity of vanadium was as high as 99.1 %. The vanadium precipitation product was hexamethyl ammonium, and the vanadium product was V2O5. It can be derived by the differential method that the reaction order was n = 2.4, the reaction rate equation was CV-1.4=kt+a, and the apparent activation energy was 27.8097 kJ/mol, which can be classified as the diffusion-controlled reaction. This innovative process enables a savings of 5050 yuan per ton of V2O5. On this basis, a complete V2O5 production process with zero waste discharge was designed.

Poster 284: The Effect of Pressurized Carbon Dioxide Lavage on Osteochondral Allograft Preparation: A Comparative Study

Objectives: Osteochondral allografts (OCA) transplantation is often utilized for treating osteochondral lesions of the knee due to limited cartilage regenerative capabilities. The use of concentrated bone marrow aspirate (cBMA) has gained traction as a method to enhance OCA incorporation and healing. Pulse lavage and pressurized carbon dioxide lavage are cleaning methods used during OCA preparation to rid native marrow elements and improve graft porosity, but their isolated and combined effects are not fully understood. This study aimed to assess the impact of incorporating pressurized carbon dioxide lavage as an adjunct to pulse lavage during OCA preparation. Our hypothesis was that adding pressurized carbon dioxide lavage would enhance the OCA absorption capacity for liquid-based materials like cBMA. Methods: OCA plugs were harvested from medial hemi-condyles. The plugs were divided into two groups: one group underwent pulse lavage alone, and the other group underwent pulse lavage followed by pressurized carbon dioxide lavage (sequential group). The plugs were weighed before and after each cleaning step and a liquid dye solution with consistency similar to cBMA was added by dripping over the cancellous portion of the graft. Next, the liquid content was determined by centrifugation and spectrophotometry. Results were analyzed statistically. Results: Thirty-four OCA plugs with a 14 to 18 mm diameter were harvested. After the cleaning phase, the sequential group showed a significant weight reduction of 107 ± 21.92% (p &lt; 0.0001) and subsequent weight gain of 96.32 ± 18.99% (p &lt; 0.0001) after the cleaning and dye-dripping procedures. In contrast, the pulse lavage-only group exhibited minimal weight loss and a small weight gain of 10.55 ± 3.86% after the dye-dripping procedure. Conclusions: Adding pressurized carbon dioxide lavage to reduce marrow elements and improve graft porosity significantly improved the OCA cleaning process and created more vacant space enhancing OCA absorption capacity for orthobiologic agents such as cBMA. The study findings highlight the potential of incorporating pressurized carbon dioxide lavage as an adjunct to pulse lavage during OCA preparation. These findings may contribute to the surgical procedure of incorporating cBMA or other orthobiologics to promote the integration and healing of OCA plugs.

A Smart Autonomous and Bluetooth Controlled Floor Cleaner

Floor cleaning is a long-standing ritual. In the past, people wanted to every day, wipe off the floor with water and a rag. Because of advancements in technology and lifestyle, people began to clean surfaces with Cloth/Thick threads connected to a stick, dipped in water. Additional time is required to Finish the floor cleaning work. People who do this work by hand take longer and are unable to accomplish it successfully since their energy levels fluctuate and they must also care for their babies and other household tasks. When a machine accomplishes the same task, it takes less time and works more effectively while using the same amount of energy. When we just have a limited amount of time, it is difficult to thoroughly clean a large area. The suggested robot is built on IoT technologies such as Arduino Uno, Bluetooth HC-05, and DC motors. and infrared sensors. In this robot, we use a smartphone app to control the cleaning process with voice commands supplied via Bluetooth module to Arduino in Manual mode. In Automatic mode, the cleaning procedure is managed by Arduino and the IR sensor, thus no human participation is required.

Sustainable Cleaning Solutions: A Microcontroller-Driven Autonomous Floor Cleaning System

The autonomous cleaning bot is a state-of-the-art robotic system that utilizes advanced cutting-edge technology to automate the cleaning process. This paper aims at presenting the design and implementation of an autonomous cleaning robot that efficiently and effectively cleans a variety of indoor spaces, from homes to commercial buildings, using a combination of sensors, algorithms, and cleaning tools. Additionally, this can detect walls and obstacles. Using various sensors, a path planning algorithm is developed to enable the robot to efficiently move and clean floors. Also, this robot can be controlled in a wireless manner via any Bluetooth-enabled device like smartphone or tablet. Localization algorithms, stereoscopic vision, wireless networks, and human-machine interaction are integrated to promote the working performance of this cleaning robot. The system's ability to navigate to specific locations according to the user’s ease and desire, in accordance with a map provided as predefined data, is showcased along with its capability to grasp objects and place them in designated locations, highlighting its improved perception and manipulation abilities. The robot is required to perform various functions such as cleaning the floor, picking up objects, and arranging them on the floor. For such a given floor task, the manipulability of the designated robot arms is analyzed through kinematics. Keywords: Autonomous floor cleaner, Sensors, Motors, Bluetooth-enabled.

Towards Integration of Ni-Slag Cleaning Process and Lithium-Ion Battery Recycling for an Efficient Recovery of Valuable Metals

Spent lithium-ion batteries (SBs) are important sources of valuable and critical raw materials. An integration of battery recycling with well-established primary processes for metals production has many advantages. In this work, the recycling of two battery scrap fractions obtained from mechanical pretreatment was integrated with a Ni-slag cleaning process at laboratory scale. Graphite from SBs acted as the main reductant, and the reduction behavior of major and trace elements was investigated as a function of time at 1350 °C. Major CO and CO2 concentrations, as well as minor amounts of SO2, NO2, CH4, and C2H4, were detected in the off-gas line. The evolution of gases took place within the first minutes of the experiments, which indicated that metal oxide reduction reactions as well as decomposition of the organic binders both happened very rapidly. This result is in line with the analytical results obtained for the slag phase, where the most significant metal oxide reduction was observed to take place within the first 5 to 10 minutes of the experiments. The distribution coefficient values for Co and Ni between metal alloy and slag as well as between matte and slag showed no significant differences when battery scrap fractions with different compositions were used. The addition of Ni-concentrate in the starting mixture resulted in increasing recoveries of Ni and Co, as well as improved settling of the matte phase.

Study on the reaction kinetics of simultaneous recovery of iron phosphate from hypophosphite in perferite oxidation plating waste

Phosphorus is an indispensable and irreplaceable element in the ecosystem. Based on the ability of ferrate(VI) to remove phosphate by producing iron phosphate, a new method for using ferrate(VI) to treat hypophosphite has been studied. In this study, ferrate was added to the hypophosphate solution in a controlled manner, and the oxidation efficiency of ferrate(VI) on hypophosphate was studied under various initial pH conditions, when the pH value of 6.0, the hypophosphate oxidation rate reached 14.0%. Research findings, Ferrate recovered hypophosphate through precipitation and adsorption under various initial pH conditions. To further investigate the mechanism of hypophosphate recovery, the morphology and microstructure of the deposition were analysed using Fourier transform infrared, X-ray diffraction, scanning electron microscopy, and X-ray photoelectron spectroscopy. The kinetic process of ferrate recovery from hypophosphate was analysed. The recovery process follows second-order reaction kinetics, and the reaction rate is highest at pH 6.0. The value of kA1 is 1.742 × 10−2. This study shows that ferrate (VI) is a promising treatment tool for low-cost phosphate wastewater. Furthermore, this method offers a clean phosphorus recovery process without the generation of harmful substances.

Indicator displacement-based colorimetric assay for dibutyl phthalate in pharmaceutical products with titanium(IV)-pyridylazo resorcinol (PAR)

Taking advantage of the competitive binding affinity towards Ti(IV) between 4-(2-pyridylazo) resorcinol (PAR) and phthalate, a simple indicator displacement (ID)–based colorimetric assay was designed for indirect determination of a well-known phthalic acid ester, dibutyl phthalate (DBP). The indicator PAR and Ti(IV) formed a purplish-red-colored Ti(IV)-PAR complex (λmax = 540 nm) at a 1:1 ratio. In the presence of pre-hydrolyzed DBP, colorless complex formation of phthalate ion (emerging from alkaline hydrolysis of DBP) with Ti(IV) resulted in a hypsochromic shift in absorbance maximum, accompanying a color change from purplish-red to yellowish-orange (λmax = 390 nm) by the release of PAR from Ti(IV)-PAR system. Based on this mechanism, the linear response range of the system for DBP was found to lie between 0.16 and 0.37 mmol L–1 with an experimental detection limit of 11.6 µmol L–1. The recommended Ti(IV)-PAR system was successfully applied to DBP-containing pharmaceutical products (as real sample) after a simple clean-up process for removing possible water-soluble interferents. The analytical results obtained from the recommended method (by applying the standard addition approach) and the reference liquid chromatography-tandem mass spectrometric (LC–MS/MS) method were statistically compared using DBP-extract of the drug samples. Consequently, a simple and selective colorimetric ID strategy was proposed for the analysis of DBP in pharmaceuticals for the first time.

Multi-Objective Optimization of Laser Cleaning Quality of Q390 Steel Rust Layer Based on Response Surface Methodology and NSGA-II Algorithm.

To improve the laser cleaning surface quality of rust layers in Q390 steel, a method of determining the optimal cleaning parameters is proposed that is based on response surface methodology and the second-generation non-dominated sorting genetic algorithm (NSGA-II). It involves constructing a mathematical model of the input variables (laser power, cleaning speed, scanning speed, and repetition frequency) and the objective values (surface oxygen content, rust layer removal rate, and surface roughness). The effects of the laser cleaning process parameters on the cleaning surface quality were analyzed in our study, and accordingly, NSGA-II was used to determine the optimal process parameters. The results indicate that the optimal process parameters are as follows: a laser power of 44.99 W, cleaning speed of 174.01 mm/min, scanning speed of 3852.03 mm/s, and repetition frequency of 116 kHz. With these parameters, the surface corrosion is effectively removed, revealing a distinct metal luster and meeting the standard for surface treatment before welding.