Efficiency Of Cleaning Research Articles

Ecological cleaning of PV panels by exploitation of dew water in Morocco

This work presents an ecological solution for cleaning of photovoltaic (PV) modules and a continuity of our first experience. It consists on using the dew water formed on the surface of the front glass. The study site is in Rabat city in the Northwest of Morocco, at the RDI (Research, Development and Innovation) Solar Energy Platform of ENS. In order to examine the effect of the angle change combined with the formation of dew water, and consequently on the cleaning of PV modules, systematic measurements of soiling ratio were made. The experiments were performed on glass plates that were exposed in real outdoor conditions. The soiling ratio was calculated by measuring the transmitted and received irradiance by the glass. At approximately sunrise, the subsequent permutation of the glass from the horizontal position to a 30° tilt angle promotes the dew droplets flow. The efficiency of cleaning is then investigated. A comparison of the soiling losses of fixed glass and variable glass with dew water flow was presented. It was found that the soiling losses for fixed glass averaged 9.3% during the exposure period while variable glass only marked 3.3%. In other words, the losses due to soiling for the fixed glass generate three times the losses compared to a variable glass with cleaning using dew water.

Influence of reactive oxygen species concentration and ambient temperature on the evolution of chemical bonds during plasma cleaning: a molecular dynamics simulation.

The research on plasma chemistry involved in the formation and dissociation of abundant chemical bonds is fundamental to developing plasma cleaning. To understand the influence of reactive oxygen species' concentration and ambient temperature on the evolution behavior of the chemical bond during plasma cleaning, microscopic reaction models between organic contaminants and reactive oxygen species were established and performed by reactive molecular dynamics. Dibutyl phthalate, as a representative organic contaminant, was selected as the research object. The simulation results suggested that hydrogen bonds between hydroxyl radicals reduced the mobility of reactive species, resulting in the cleaning ability of hydroxyl radicals being much lower than atomic oxygen and ozone radicals. The concentration of reactive species dominated the efficiency of plasma cleaning, and the increase in ambient temperature further improved the cleaning ability. C-H, C-C and C-O bonds were gradually oxidized to C[double bond, length as m-dash]C, C-O, C[double bond, length as m-dash]O and O-H bonds by hydrogen abstraction reaction during the reaction of reactive species with organic contaminants. An increase in ambient temperature induced the possibility of benzene ring destruction under the action of reactive species, which was considered a method of complete dissociation of aromatic hydrocarbons.

The Efficiency of Chemical Cleaning of Different Metal Artefacts from Felix Romuliana and Gradina Archaeological Sites (Serbia)

The Efficiency of Chemical Cleaning of Different Metal Artefacts from Felix Romuliana and Gradina Archaeological Sites (Serbia)

The Effect of Alkali and Surfactant Concentration, Temperature and Stirring on the Cleaning Efficiency of the Carbon Steel Surface

"Electrostatic painting is the fastest and most efficient technology through industrial paints due to its impact on the environment, and also for its very easy application on different surfaces. The first and most important stage of the electrostatic painting is to clean the surface to be painted by removing the dirt, lubricants, oils, metal oxides or welding residues. In order to increase the efficiency of carbon steel surface cleaning, the influence of alkali and surfactant concentrations, temperature and stirring was investigated. To produce a uniform surface required for the electrostatic painting, some degreased samples were subjected to pickling operation using aqueous HCl solution. Keywords: carbon-steel, degreasing, pickling, ultrasonication "

Membrane cleaning in membrane distillation of reverse osmosis concentrate generated in landfill leachate treatment.

As a thermally induced membrane separation process, membrane distillation (MD) has drawn more and more attention to the advantages of treating hypersaline wastewaters, especially the concentrate from the reverse osmosis (RO) process. One of the major obstacles in widespread MD application is the membrane fouling. We investigated the feasibility of direct contact membrane distillation (DCMD) for landfill leachate reverse osmosis concentrate (LFLRO) brine treatment and systematically assessed the efficiency of chemical cleaning for DCMD after processing LFLRO brine. The results showed that 80% water recovery rate was achieved when processing the LFLRO brine by DCMD, but membrane fouling occurred during the DCMD process, and manifested as the decreasing of permeate flux and the increasing of permeate conductivity. Analysis revealed that the serious flux reduction was primarily caused by the fouling layer, which consisted of organic matter and inorganic salts. Five cleaning methods were investigated for membrane cleaning, including hydrogen chloride (HCl)-sodium hydroxide (NaOH), ethylene diamine tetraacetic acid (EDTA)-NaOH, citric acid, sodium hypochlorite (NaClO) and sodium dodecyl sulphate (SDS) cleaning. Among the chemical cleaning methods investigated, the 3 wt.% SDS cleaning showed the best efficiency at recovering the performance of fouled membranes.

Efficiency assessment of electricity generation in China using meta-frontier data envelopment analysis: Cross-regional comparison based on different electricity generation energy sources

China is the world's largest electricity producer and consumer, and the healthy development of the electricity industry contributes to its economic growth and social stability. Yangtze River Economic Belt (YREB) and non-YREB are two major economic engines of great strategic significance for China with distinct differences in the external development environment of their power industry. A cross-regional comparison of electricity generation efficiency in China is meaningful to obtain a more accurate understanding of the power generation efficiency of YREB and non-YREB, but there is currently no literature in this area as well as none for comparing electricity generation efficiency between different energy sources. Therefore, this research uses the meta-frontier epsilon-based measure (EBM) data envelopment analysis (DEA) model to calculate the efficiency of different electricity generation energy in YREB and non-YREB for the period 2013–2017. The empirical results show that: 1) YREB's electricity industry has higher electricity generation efficiency than non-YREB's, and the efficiency gap is continuing to widen; 2) YREB's average thermal electricity generation efficiency is higher than non-YREB's; 3) YREB's clean energy power generation efficiency is always higher than non-YREB's; 4) regional differences in YREB are smaller than those in non-YREB; and 5) the efficiency value of clean energy power generation is lower than that of thermal power generation. From our analysis results, this paper presents some policy recommendations.

Theoretical study of the impact aimed at improving the efficiency of fiber cleaning

Since cotton cleaning in Uzbekistan is carried out mainly manually, this paper discusses the methods and technologies established in the process of cleaning cotton and fiber. The process of fiber cleaning is one of the important processes that complete the technological process of cotton processing, given that the quality of fiber largely depends on the efficiency of this process, the research work on the mechanization of the type of collection and improving the efficiency of its cleaning is analyzed. In order to improve the efficiency of cleaning cotton collected on the machine, information is provided on the need to improve the equipment for cleaning fiber used in cotton gins. The research results are based on the need to replace a special structural device that guides the fiber to the correct tooth of the first sawtooth cylinder located on two drum cleaning plants. New fiber-cleaning equipment was installed in the Jizzakh regional JSC “Zarbdor cotton cleaning» and experimental tests were conducted in production conditions. In addition, the process of changing the pressure, density and speeds in the furnace and the effect of their cleaning efficiency has been modeled and theoretically analyzed, when the efficiency of cleaning the cotton fiber flow using a column system allows changing the raw material from 4 mm to 15 mm based on the device. By results of the conducted analysis it was shown that the increase of efficiency of purification depends on the device attached to the saw teeth, factor of the taxation of the distribution coefficient B and p 0 efficiency factor of increasing the initial pressure and coefficient of efficiency savings from the analysis of graphs, which present graphs of the distribution depending on the type of saw teeth. Based on the results of the research, recommendations are given for the widespread introduction of fiber cleaning equipment installed at enterprises of primary cotton processing, with the installation of a special structural guide device.

Key Factors Influencing the Achievement of Climate Neutrality Targets in the Manufacturing Industry: LMDI Decomposition Analysis

The manufacturing industry is often caught in the sustainability dilemma between economic growth targets and climate action plans. In this study, a Log-Mean Divisia Index (LMDI) decomposition analysis is applied to investigate how the amount of industrial energy-related CO2 emissions in Latvia has changed in the period from 1995 to 2019. The change in aggregate energy-related CO2 emissions in manufacturing industries is measured by five different factors: the industrial activity effect, structural change effect, energy intensity effect, fuel mix effect, and emission intensity effect. The decomposition analysis results showed that while there has been significant improvement in energy efficiency and decarbonization measures in industry, in recent years, the impact of the improvements has been largely offset by increased industrial activity in energy-intensive sectors such as wood processing and non-metallic mineral production. The results show that energy efficiency measures in industry contribute most to reducing carbon emissions. In the future, additional policies are needed to accelerate the deployment of clean energy and energy efficiency technologies.

Influence of ionic strength and surfactant concentration on the alkane contaminant desorption in solution: A molecular dynamics simulation

The cleaning of the optical and mechanical components in a high-power laser system is essential for the cleaning control of the high-power laser system. Many factors affect the cleaning efficiency of the solution cleaning. Ion concentration, surfactant concentration and molecular weight of organic molecules are three key factors. In this article, equilibrium and nonequilibrium molecular dynamics simulations are performed to investigate the interfacial interaction among fluid, substrate and oil droplets and the dynamic desorption process of the oil droplet. As the increase of ion concentration, the contact angle of the oil droplet decreases, and the height of the oil droplet decreases slightly. Higher ion concentrations make the oil droplet more hydrophobic because of the reduction in hydrogen bonds between oil droplets and water and the reduction in residual time. In water flow simulation, high ion concentration is not beneficial to the desorption of oil droplets. Pure water flooding is not effective as brine flooding, which is related to water flow velocity. High surfactant concentration is beneficial to the desorption of oil droplets without water flow. Alkane molecule with larger molecular weight is difficult to detach from the solid surface, since the higher interaction energy between alkane molecule and substrate.

Comparison of Canal Transportation and Centering Ability of One-G, EdgeGlidePath, and Neolix: A MicroComputed Tomography Study of Curved Root Canals

Aims A glide path is created prior to root canal instrumentation by nickel-titanium (NiTi) rotary files to increase the efficiency and safety of cleaning and shaping. This study aimed to assess root canal transportation in use of different glide path files in curved canals. Materials and Methods 30 sound mesiobuccal root canals of mandibular molars with 20° to 40° curvature were selected and randomly assigned to 3 groups of EdgeGlidePath (EGP, EdgeEndo), One-G (Micro-Mega), and Neolix (Neoniti). The specimens were scanned before and after glide path creation by microcomputed tomography (micro-CT). The pre- and postoperative micro-CT scans were superimposed, and the degree of canal transportation and centering ratio were measured at 1, 3, 5, and 7 mm distances from the apical foramen. Statistical Analysis. The data were analyzed by two-way and one-way ANOVA. Results The effects of distance from the apical foramen and instrument type and the interaction effect of the two were not significant on the centering ability of the files or canal transportation. Conclusion EdgeGlidePath, One-G, and Neolix files fabricated from the conventional NiTi alloy or heat-treated M-Wire alloy showed similar performance regarding centering ability and canal transportation in glide path preparation in curved canals.

МЕХАНИЗИРОВАННАЯ ОЧИСТКА И ДЕЗИНФЕКЦИЯ СЕКЦИОННЫХ ИНСТРУМЕНТОВ С ПОМОЩЬЮ УЛЬТРАЗВУКА КАК ОДИН ИЗ ЭТАПОВ СОВЕРШЕНСТВОВАНИЯ ПРОТИВОЭПИДЕМИЧЕСКИХ МЕРОПРИЯТИЙ В БЮРО СУДЕБНО-МЕДИЦИНСКОЙ ЭКСПЕРТИЗЫ

Introduction. An analysis of the most time-consuming and dangerous tasks for medical personnel shows that one of them is the cleaning of medical instruments from contamination. The same applies to sectional instruments used in the operations of the Bureau of Forensic Medicine during autopsy of corpses. To solve this problem, mechanized cleaning through the use of ultrasonic cleaners is increasingly applied in global practice. Aim. The aim of the work was to organize the washing and disinfection of sectional instruments by mechanized method using ultrasonic washers and to evaluate the efficiency and quality of instrument cleaning. Material and methods. We analyzed the experience of the Republican Bureau of Forensic Medicine of the Ministry of Health of the Republic of Tatarstan in the organization ВЕСТНИК СОВРЕМЕННОЙ КЛИНИЧЕСКОЙ МЕДИЦИНЫ 2021 Том 14, вып. 6 29ОРИГИНАЛЬНЫЕ ИССЛЕДОВАНИЯ and provision of washing and disinfection of sectional instruments. We developed basic principles of operation and standard operating procedures for the personnel of thanatology department with regard to mechanized washing and disinfection of sectional instruments in ultrasonic washing. We evaluated the effectiveness of the implemented measures by conducting sanitary and bacteriological examination and by testing the effectiveness of ultrasound treatment of instruments. Results and discussion. Ensuring the safety of personnel working in the expert institution dictates the necessity of mechanization and automation of production processes in the area of cleaning and disinfection of metal instruments. In this regard, standard operating procedures for personnel based on the current regulatory documents were developed and implemented. The effectiveness of the implemented measures was further evaluated. Sanitary and bacteriological studies in the control group (before the implementation of standard operating procedures) revealed E. coli bacteria in 15% of the samples. Staphylococcus aureus was not detected in any of the samples. All samples containing E. coli group bacteria were in the washes taken from the scissors. In the experimental group (after implementation of standard operating procedures), E. coli and Staphylococcus aureus bacteria were not detected in all samples. When evaluating the efficiency of instrument washing in an ultrasonic washer, 98,33% of SteriTEC indicators for instrument cleaning reached the optimal variant. Conclusion. Thus, the introduction of modern, mechanized methods of instrument processing into the activities of medical and preventive treatment institutions, in particular forensic medicine bureaus, can significantly improve the quality of cleaning and disinfection of metal instruments involved in the performance of examinations. Such innovations must be accompanied by a comprehensive approach in solving sanitary and hygienic problems and be supported by clear guidelines and standard operating procedures for personnel.

Design and simulation of proton exchange membrane fuel cell system

Proton exchange membrane fuel cell system has been proposed as an alternative to the internal combustion engine due to its clean and high efficiency. Analysis of the coupling effects among components is critical to improve the design of the fuel cell system and shorten the development cycle. In this paper, the steady-state modeling of a fuel cell system is developed, focusing on the coupling effects between various components and the influence of operating conditions on the internal parameters. Firstly, the model of each component is established based on the mechanism or experience, and the boundary conditions of each component model are defined. Then, the component models are integrated into a system model, and the operation parameters of the system are solved by an iterative method. The operation conditions at different ambient temperatures are simulated and the results are discussed. It is indicated that a higher ambient temperature will significantly increase auxiliary power consumption and decrease system efficiency. The steady-state model proposed in this paper predicts the operation parameters of the system, which is helpful to reduce the development cost.

Assessment of the efficiency of different chemical treatments and ultrasonic cleaning for defatting of cancellous bone samples

Our study aimed to asses the defatting efficiency of different methods, which are commonly used and easily available in the laboratory in order to find a method that is effective, convenient, safe, and economical. Cylindrical cancellous bone specimens were obtained from fresh-frozen human cadaver femoral condyles, cut into multiple small specimens (Ø8 × 2 mm), and assigned to two groups that were treated with either chemical solvent soaking (Solvent group) or ultrasonic cleaning (Ultrasound group). Each group was divided into several subgroups based on different treatments. Digital photographs were taken of each specimen. The difference of material density (Δρb), apparent density (Δρapp), and porosity (ΔP) before and after treatment were used as evaluation indicators. For the solvent group, in Δρb, only the combination of 99% ethanol and detergent solution showed a significant difference before and after treatment (P = 0.00). There was no significant difference in ΔP among acetone, the mixture of 99% ethanol and acetone, and the combination of 99% ethanol and detergent solution (P = 0.93). For the ultrasound group, the median of all subgroups in Δρapp and ΔP were all lower than the solvent group. The combination of 99% ethanol and detergent solution (v/v = 1:20), as well as the mixture of 99% ethanol and acetone (v/v = 1:1), seem to be the optimal defatting methods for 2 mm thick cancellous bone slices due to their effectiveness, availability, low-cost and safety. Chemical soaking for 24 h is more effective than ultrasonic cleaning with 99% ethanol or acetone for 20 or 40 min.

New Approach Study on Dry Coal Cleaning System with Two-Stage Corona Electrostatic Processes for High-Sulfur Low-Grade Fine Coals

Corona electrostatic separation can remove inorganic materials from coal, reduce coal ash content and sulfur content and improve coal quality, reduce air pollution caused by smoke dust, SOX, and COX. The performance of corona electrostatic separation technology in cleaning a middle ash medium-ash, high-sulfur coal was experimentally investigated. The electrode voltage, drum rotational speed, and feeding speed were tested, whereas other parameters were maintained constant during the experiment. The results indicate that the performance of this technology in cleaning medium-ash, high-sulfur coal can be improved by optimizing the process parameters. The results demonstrate that corona electrostatic separation is effective for the beneficiation of this grade coal. In addition, the efficiency of coal cleaning is significantly improved by adding the second stage beneficiation to clean the middlings out from the first stage beneficiation. In this study, the first stage of beneficiation recovered 38.00% (by weight) of clean coal (ash content below 20%), and the second stage recovered 48.58% (by weight) of clean coal, improving the overall separation efficiency from 0.69 to 1.74. Furthermore, the sulfur content was reduced from 4.71% (raw coal) to 3.53% (clean coal). Our result show that corona electrostatic separation can effectively reject inorganic sulfur from raw coal, and the two-stage separate is also very helpful for coal purification.

ANALYSIS OF THE MOVEMENT OF THE WORKING BODIES OF THE WOOL PLANT CLEANING MACHINE

Nowadays, the demand for quality natural fibers is growing. For the textile and light industry, it is important that the natural properties of wool are preserved. But the techniques and technologies for obtaining high-quality wool fiber are becoming obsolete, both spiritually and physically. With this in mind, an efficient, resource-efficient design of equipment for cleaning wool from plant mixtures will be developed. This equipment effectively cleans the wool from plant mixtures, maintaining its quality. The efficiency of wool cleaning in the equipment is directly affected by the rotational frequencies, moments of inertia, technological processes, geometric, kinematic and dynamic parameters of the working bodies. Therefore, a dynamic analysis of the equipment was performed to substantiate the parameters of the working bodies.

Selection of recycled water electrochemical conditioning parameters for preparation of diamond-bearing kimberlite for froth separation

The main reason of decreasing diamond recovery through froth separation is their surface hydrophilization by hypergene minerals and technogenic films, crystallized from the supersaturated aqueous phase, fixed on the surface structurally or by adhesion. Various types of physical actions, including thermal and ultrasonic treatment of the initial feed of froth separation, are recommended to increase the diamond-bearing kimberlite beneficiation process performance, providing cleaning of the surface of diamonds due to destruction of their accretions with rock minerals and removal of film hydrophilizing coatings from the surface of diamond crystals. A sample of kimberlite material with a given content of diamonds of 1.5–2 mm in size was used as a subject of research in the process of froth separation. The results of thermodynamic calculations and experimental research have substantiated the necessity of using electrochemical conditioning of recycled water for increasing the efficiency of diamond surface cleaning in froth separation operation when using the process of thermal treatment of initial ore feed. The use of diaphragmless electrochemical conditioning of recycled water increases the efficiency of thermochemical dissolution of hydrophilizing compounds on the surface of diamonds through reducing the concentration of calcium and carbonate ions as well as through shifting the medium pH to 6.1–6.5. The measurements of the limiting wetting angle showed that the maximum effect of increasing the diamond surface hydrophobicity was achieved when heat and electrochemical treatment were used together. Laboratory studies showed the possibility of increasing flotation diamond extraction from 65.7 to 91.4 % through application of electrochemical conditioning of recycled water. The optimum parameters of diaphragmless electrochemical treatment of recycled water of the froth separation cycle in conditions of application of pulp heat treatment: current density of 175–200 A/m2 and power consumption of 1.2–1.5 kWh/m3. Tests carried out at processing plant No. 3 of the Mirny GOK (Mining and Processing Complex) (Mirny, Yakutiya) showed that the application of the developed froth separation process intensification method with the use of thermal treatment of pulp and electrochemical diaphragmless treatment of recycled water allowed increasing the recovery of diamonds of +0.5–2 mm size by 4.9–5.1 %.

Cleaning of humid air from ammonia impurities by UV radiation

The removal of ammonia impurities (100–200 ppm) in a humid air flow with a flow rate of 30–150 m3/h by ultraviolet radiation of an low-pressure amalgam lamp with a wavelength of 185 nm and 254 nm was experimentally investigated. The presence of water vapor is necessary for the effective removal of impurities by UV radiation, since highly active OH and atomic hy-drogen H radicals are formed during the dissociation of water molecules. The presence of water droplets dramatically reduces the efficiency of cleaning. The main reactions of photooxidation are considered. The high efficiency of removing ammonia molecules by one photon of 185 nm is noted.

Application of ORC in a Distributed Integrated Energy System Driven by Deep and Shallow Geothermal Energy

This study presents a distributed integrated energy system driven by deep and shallow geothermal energy based on forward and reverse cycle for flexible generation of cold, heat and electricity in different scenarios. By adjusting the strategy, the system can meet the demand of heat-electricity in winter, cool-electricity in summer and electricity in transition seasons. The thermodynamic analysis shows that the thermal efficiency of the integrated energy system in the heating and power generation mode is 16% higher than that in the cooling and power generation mode or the single power generation mode. Meanwhile, the annual heat-obtaining quantity of the system is reduced by 11% compared with that of the independent power generation system, which effectively alleviates the imbalance of the temperature field of the shallow geothermal reservoir. In terms of net power generation, the integrated energy system can generate approximately 31% more electricity than the conventional independent cooling and heating system under the same cooling and heating capacity. An integrated system not only realizes the comprehensive supply of cold and thermal ower by using clean geothermal efficiency, but also solves the temperature imbalance caused by the attenuation of a shallow geothermal temperature field. It provides a feasible way for carbon emission reduction to realize sustainable and efficient utilization of geothermal energy.

Airflow-assisted electrodynamic cleaning of sand deposited on solar panels

Soiling of photovoltaic panels owing to deposition of sand on the panel decreases the efficiency of energy generation in utility-scale power plants installed in deserts and arid areas. This problem can be solved using electrodynamic cleaning systems that utilize electrodynamic traveling waves or standing waves on solar panels for waterless cleaning with minimal energy requirements and without requiring any manpower or consumables. An auxiliary mechanism is developed to enhance the cleaning efficiency of electrodynamic cleaning, in which airflow is applied on the panel surface to improve the cleaning performance. This technology utilizes natural wind amplified by a passive slit placed at the upper end of the inclined panel. The wind velocity increased to approximately four times that of natural wind, and the cleaning performance improved, particularly in the highly soiled panel. This mechanism is simple, potentially inexpensive, requires no electric power, and operates without water, consumables, or manpower.

Investigation of the Jet Characteristics and Pulse Mechanism of Self-Excited Oscillating Pulsed Jet Nozzle

Self-excited oscillation pulse jet technology is widely used to clean sediment from oil storage tanks. Its successful application is dependent on jet performance. As the cleaning requirements of the oil industry increase, it is necessary to optimise the structure of self-excited oscillation pulsed jet nozzles (SOPJNs) to optimise cleaning and energy efficiencies. In this study, the jet performance of a SOPJN is modelled and analysed based on computational fluid dynamics with consideration of a large eddy simulation and homogeneous cavitation. The modelling results are highly consistent with experimental results. The effects of the SOPJN’s inlet diameter, cavity diameter, cavity length, wall reflection angle, and inlet pressure on the jet’s peak velocity, oscillation frequency, and cavitation number were analysed. The results show that the oscillation frequency decreases with the increase of the inlet diameter d1, cavity diameter D, cavity length L and reflection angle of wall α. Optimisation of the SOPJN inlet diameter, cavity length, and wall reflection angle produced a jet with a high peak velocity and strong cavitation. The optimal nozzle cavity diameter strengthens cavitation, while the peak velocity fluctuates as the cavity diameter increases. The peak velocity increases with the inlet pressure, while the increasing rate of the peak velocity decreases. The results of this study can be used in the design and optimisation of similar nozzle structures for improved pulse jet cleaning.