Solid Contaminants Research Articles

Analysis of contamination and jamming characteristics of fuel metering device based on OMEGA theory

In order to obtain the quantitative law of the influence of pollution particles in fuel on the working characteristics of fuel metering devices and explore an analytical method for the pollution sticking characteristics of non-standard fuel components, the effect of pollution particles on fuel components is converted into sticking force based on the OMEGA theory, and the dynamic model of fuel components and devices under fuel pollution conditions is established. The working characteristics of the fuel metering device when the solid contamination level is GJB450B-7/8/9 is simulated, and the influence of each grade of fuel on the performance of its key components is obtained. The results show that the load flow response obtained by the servo valve contamination sticking model is basically consistent with the results of the standard servo valve contamination sticking model. The maximum sticking force of the metering valve in the 9-grade fuel is about 140 N, the response time is more than twice that of the non-polluting state, and the maximum relative error of the metered fuel quantity increases by more than 4 times. The method proposed in this paper can provide a reference for the pollution sticking modeling of non-standard fuel components and systems.

Orifice erosion effect and variable gain control method for hydraulic servo spool valve

The hydraulic servo valve orifice becomes blunted due to erosion caused by solid particle contaminants in the oil, leading to a decline in the valve's static and dynamic performance. This study analyzes the working edge scanning model and proposes using a quarter-ellipse curve to fit the working edge contour for the precise calculation of the valve orifice area. Through AMESim simulation, this study investigates the relationship between valve orifice erosion and the static and dynamic characteristics of hydraulic servo slide valves and proposes a variable gain control method for addressing valve orifice erosion. Results show that the orifice area model based on the quarter elliptic curve is accurate. As erosion increases, the nonlinear area of the valve orifice curve expands, and the valve orifice degrades into a positive opening. The ratio of the long diameter to the short diameter of the ellipse is approximately linearly related to the pressure gain and leakage in the static characteristics of the hydraulic servo valve. After variable gain control, the static and dynamic characteristics of the servo valve closely resemble those of an ideal servo valve, with the maximum deviation between the flow characteristics and the ideal valve orifice approximately 1 %. Regarding pressure characteristics, the pressure drop before the zero position is below 0.2 MPa. This study establishes the internal relationship between orifice erosion and performance degradation and provides a novel approach to enhancing the erosion resistance of hydraulic servo valves.

Wettability/anti-icing properties of hierarchical Micro/nanostructured copper surface prepared by Micro milling and chemical etching

Ice accumulation on the metallic surface usually results in seriously economic losses, resource wastes and even hazard accidents. Superhydrophobic surfaces (SHSs) are recognized as one of the most promising candidates for water repellence and anti-icing, offering both environmental and economic advantages over the traditional methods. The ordered microstructure arrays with controllable parameters play an essential role in mechanism analysis, rational design and reproducible construction of SHSs. However, the efficient fabrication of ordered microarrays on metal substrates with high resolution and high accuracy is still fraught with significant challenges. Here, a multilevel micro/nano surface with rectangular micropillars was fabricated on copper substrate by the integration of micro milling and chemical etching, which exhibits superior superhydrophobicity with water contact angle of 171.1 ± 1.5° and sliding angle of 2.2 ± 0.7°. The developed deburring scheme makes an outstanding contribution to the in-situ removal of milling burrs generated on the top of micropillars. The variation in surface wettability with microarray geometry and etching conditions indicates that a favorable surface morphology is crucial for improving the water repellency of the surface. The results of the durability experiment and the self-cleaning test demonstrate the robust comprehensive stability of the prepared SHSs against moisture, high temperature and mechanical wear, as well as the superior fouling resistance against solid and liquid contaminants, which is mainly ascribed to the hierarchical micro/nanostructures. Moreover, the present micro/nanostructures are also demonstrated to be capable of enhancing the delayed icing performance of the copper surface, with the freezing time of a 5 μL water droplet being 519.86 ± 13.53 s. Meanwhile, the superhydrophobic copper surfaces exhibit remarkable anti-icing behavior against saline solutions, as evidenced by the freezing time of 1078.42 ± 31.24 s for a 5 μL NaCl droplet. This work provides a sustainable and high-precision approach for the fabrication of metal-based SHSs, expecting to advance the theoretical research and industrial applications of anti-icing functional surfaces.

Microvolume analysis of 226Ra by inductively coupled plasma mass spectrometry: Environmental applications to high-resolution profile of wetland soil pore waters

BackgroundThe release to the environment of natural radionuclides like 226Ra due to human activities have raised concerns about human and ecosystem exposure. 226Ra’s resemblance to calcium and involvement in biological processes accentuate the importance of understanding its geochemical behavior and migration pathways. Soil and sediment pore waters provide valuable information but have proved to be challenging to analyze, requiring to push the limits of current sample preparation and detection methods often not scaled for low concentrated microvolumes of samples. A more efficient and accurate analytical method is therefore needed to get reliable data to support hydro-geochemical modeling. ResultsWe describe here a novel comprehensive approach for accurate 226Ra quantification in pore waters of a wetland located downstream of the former Rophin uranium mine. In order to highlight the migration of 226Ra between the different soil layers, microvolumes of soil pore waters were in situ sampled up to 50 cm depth employing Diffusive Equilibrium in Thin-Films (DET) probes. The workflow included spiking DET extracts with an in-house 228Ra tracer, specific solid-phase extraction with 50 mg of AnaLig Ra-01® resin, and elution fraction calcination. This process eliminated interferences and simplify the analysis matrix. Quantification relied on isotope dilution after measurement by ICP-MS hyphenated to a desolvator module and to a microsampler (150 µL injection). The resulting 1 cm-high-resolution profile revealed unusual 226Ra enrichment with depth, signs of Ra mobility from the solid contamination source. These elements are essential for assessing 226Ra distribution coefficients across soil horizons and subsequent wetland remobilization considerations. Significance and noveltyThis first methodological advance for 226Ra constitutes a significant step to understand 226Ra behavior i.e., to quantify its activity level, fluxes inside of wetland soils or at the interface overlying waters/sediments. Its potential extension to studies involving other elements underscores its broader applicability in environmental research. The findings contribute to evidence-based decision-making for environmental protection and management, aiding in the preservation of ecological integrity and human health.

The influence of the precursor type in the synthesis of Mg/Al-hydrotalcite through a non-traditional method used for Claisen-Shmidt condensation

Traditionally, the synthesis of MgAl-hydrotalcite is performed in the presence of inorganic alkalis-type precipitating agents using the co-precipitation method. As an viable alternative, the use of organic alkalis and the mechanochemical method can remove some of the issues that the traditional route generates, i.e. the possibility of final solid contamination with alkaline cations; a high energy consumption, relative to the amount of water used but also of electric current; the involvement of a large number of utensils necessary for the synthesis; time allocated to the solid preparation; etc. Changing the regular precursor type (i.e. nitrate) of the target cation with chloride or sulfate leads to obtaining hydrotalcites which have different basicities. The chlorides precursors lead to the synthesis of materials that show a better ability for the reconstruction of the layered structure. Moreover, TMAH acts both as a synthesis agent and as a templating agent. The tight pore distribution is characteristic of all materials obtained from chloride precursors, where the co-precipitation method generates pores of 97Å, while the mechanochemical method generates pores of 140Å. The material with the highest catalytic activity for Claisen-Schmidt condensation, conversion of 92%, is the one obtained by calcination of the hydrotalcite prepared from chloride precursors by the mechanochemical method, while the co-precipitation method leads to conversions of 90%. The novelty of this work is that these type of catalysts obtained from chlorides or sulfate precursors in presence of TMAH have not been used in Claisen-Schmidt condensation until now.

Resource Utilization of Solid Waste and Water Quality Evaluation

The rapid development of industrialization and urbanization has inevitably resulted in the generation of innumerable solid wastes and water contamination [...]

Computational assessment of ratcheting in rail-wheel contact with solid contaminant

A numerical method for the fast evaluation of ratcheting in solid-contaminated contact between rollers was developed. The physical problem was simplified with a plane-strain half-infinite body, with a distribution of pressure and tangential stress on the contact surface obtained by considering the presence of evenly spaced solid contaminant particles between the contacting bodies. Such a distribution was obtained by an analytical method, which considered the material of the contacting bodies as linear elastic. The stresses under the contact surfaces were calculated using the Boussinesq-Cerruti model. Subsequently, the plastic strain accumulated in the roller after each application of the contact load was calculated by means of a non-linear kinematic-hardening constitutive law, also considering the effect of wear in removing material layers from the surface.First, the effects of the introduced approximations were evaluated. In particular, the error in calculating the plastic strain using contact load distributions from a theory based on linear elastic behavior was evaluated by comparison with the results of finite element models. Subsequently, the method was used to assess the experimental results of previously published studies on sand-contaminated contact between rail and wheel materials. Despite the approximations and indetermination of some model constants, the method was proven to be able to qualitatively explain many of the damage mechanisms related to the interaction of the contacting bodies with the contaminant particles.

Assessment of environmental impacts of the Céu Azul Dump, Camaragibe/PE, Brazil

Dumps consist of inadequate disposal of solid waste, causing soil and water contamination, air pollution, and proliferation of vectors. After the landfill's closure, it continues to cause environmental damage and public health, requiring adequate site remediation. Thus, an ecological diagnosis is necessary to characterize the environmental situation found before carrying out the closure project. Therefore, this diagnosis should represent the first stage and the basis for all projects, where it is possible to describe and identify environmental impacts and point out the best ways to mitigate these generated impacts. This study aimed to evaluate the ecological effects of the Céu Azul dump in Camaragibe, Metropolitan Region of Recife, Pernambuco. The investigation began employing the physiographic characterization of the area, where the climate, hydrology, geology, geomorphology, and pedology of the region of the old dump. Subsequently, field and laboratory tests, such as SPT-type soundings, infiltration tests, flow plates, soil collection, and surface and underground water quality in the surrounding area, were carried out. Regarding the assessment of environmental impacts, the main impacting factors verified in areas of final waste disposal were first drawn up (whether or not an occurrence was confirmed). After this step, each impact was hierarchized in such a way as to allow a more precise visualization of the diagnostic scenario. In the case analyzed, the Camaragibe municipal dump has negative environmental impacts, which require remediation of the area.

Preparation of paper scintillators and their effective use in radiation testing for [formula omitted]- and [formula omitted]- particles in radioactive liquid, solid, and gas contaminants

A paper scintillator, which is composed of an organic scintillator encapsulated in silica nanoparticles adsorbed on three types of micrometer-size silica fine powder (scintillator–silica FP), was prepared by a paper making method. The scintillator–silica FP was found to be distributed throughout the paper scintillator, as shown in its emission images. Surface photoluminescence spectra depended on the amount of scintillator–silica FP and were assigned to the radioluminescence excited upon irradiation with β-particles of 45Ca. The onset channels of the pulse height spectra of 3H, 63Ni, 14C, 45Ca, 204Tl, and 32P indicated their dependence on linear energy from 18.6 to 1711 keV using the H mode in LSC-7400 for the paper scintillator to detect their maximum β-particles energies. The paper scintillator could also detect α-particles from 211At, and its pulse height spectrum was wider than that of a liquid scintillator (LS). Radon gas in air was collected using a gas sampler with the paper scintillator, and radiation from daughter nuclides was detected for 10 days. The adsorption/absorption of tritiated water onto/into the paper scintillator after dipping, dropping, and immersing the paper scintillator into tritiated water led to the detection of β-particles under different conditions of tritiated water for determining whether the radioactivity in the solution, is high or low. The paper scintillator smeared with tritiated contaminants detected tritium without requiring an LS, which is used in a smear paper.

Penerapan Automatic Particle Counter untuk Pemantauan Kondisi Oli Hidrolik

High solid particle contamination in hydraulic oil can cause abnormal damage to hydraulic system components. Monitoring the hydraulic oil solid particle contamination level is necessary to ensure it is always within permissible limits. Monitoring of solid particle contamination in hydraulic oil is still done manually by taking an oil sample and then measuring the level of solid particle contamination in the oil sample. This method still relies on human power. Therefore, there is still a possibility that oil conditions are not monitored due to human negligence. This research aims to design a system that automatically samples hydraulic oil and measures solid particle contamination. The level of solid particles in the hydraulic oil is measured by the Automatic Particle Counter (APC) sensor, and then the data is sent to the microcontroller. The microcontroller will process this data and provide information regarding the level of solid particles in the hydraulic oil in real-time. This research produces a system that automatically monitors and produces ISO Cleanliness Code values and a warning system when solid particle levels exceed specified limits. Therefore, this tool can help users monitor hydraulic oil conditions more easily.

Machine Learning Approach for Predicting the Solid Particle Lubricant Contamination in a Spherical Roller Bearing

Machine Learning Approach for Predicting the Solid Particle Lubricant Contamination in a Spherical Roller Bearing

Estimating solid contaminant levels in beach sands through petrographic analysis, screening evaluation, and optical imaging

Estimating solid contaminant levels in beach sands through petrographic analysis, screening evaluation, and optical imaging

Investigating the influence of nano-silica incorporation on mechanical characteristics of steel fiber-reinforced concrete to mitigate solid waste and environmental contamination

ABSTRACT Using nano-silica and steel micro-fibers in high-strength concrete has gained attention due to their potential to reduce solid waste and environmental pollution. In this study, the impact of nano-silica inclusions on the mechanical properties of steel fiber-reinforced concrete, referred to as “Micro-Concrete Reinforced with Steel Fibers Embedding Nano-Silica” (MRSFEN), was assessed. MRSFEN mixtures were prepared with 0%, 1%, and 2% nano-silica content and 0.5%, 1%, 2%, and 3% steel micro-fiber content. Tests showed a 17%-32% increase in compressive strength and a 12%-29% increase in tensile strength by adding 1%-2% nano-silica across all fiber contents. Incorporating 1%-3% steel micro-fibers resulted in 18–25 MPa higher compressive strength, 6–12 MPa higher tensile strength, and 10%-35% higher flexural strength relative to non-fiber concrete. However, workability reduced by 15%-30% with 3% fiber content. The combined use of nano-silica and steel micro-fibers enhanced strength and ductility, with the optimum composition identified as 1% nano-silica with 2% steel micro-fibers based on the mechanical performance. The results indicate the potential of tailored MRSFEN mixtures to improve the mechanical properties of steel fiber-reinforced concrete, with benefits in reducing solid waste and mitigating environmental contamination.

A review of bio-inspired fouling resistance surfaces

Solid fouling settlement, defined as the unexpected payment of various types of solid contaminants, including ice, wax, bacteria, and protein, can result in many problems in daily life and production and cause economic and security losses. Despite many traditional methods for reducing foulant to make a more durable and efficient antifouling surface, many artificial surfaces inspired by the natural antifouling material which the environment has selected during the process of evolution, including lotus leaf, pilot whale skin, gecko feet, shark skin, and pitcher plant are developed to resist adhesion of multiple foulants in an efficient and environmentally friendly way. In this review, the mechanism of how surfaces using patterns similar to the natural antifouling surface resist fouling materials is overviewed. Various methods for fouling formation classify the hazard, properties, and characteristics of different fouling materials. The approaches typically applied in designing a surface with high fouling resistance are presented first. After interpreting the theories and models mentioned in the explanation of the fouling resistance property, the textural microstructures, the chemical and physical properties used, and applications for fouling resistance of several bio-inspired fouling resistance surfaces, and how these surfaces can be improved in the future are discussed.

Evaluation of Darbandikhan Lake and its tributaries' water quality in the Sulaymaniyah Province in Iraqi Kurdistan, using the water quality index model and multivariate statistical analysis.

This study evaluated the characteristics of the water in Darbandikhan Lake and its rivers in the Kurdistan Region of Iraq. For this purpose, 25 samples were collected seasonally and analysed for 36 physiochemical parameters. The proportions of physiochemical parameters exceeding the WHO standards in the samples with their highest exceedances were 9894% for Al, 198% for Mn, 40% for Pb, 1.6% for pH, 3250% for PO4, 11.8% for Sr, 155% for T.Alk, 7813% for turbidity, 1188% for Ti, 1033% for Tl and 1293% for V in the river water and 120% for Co, 74% for Cr, 4485% for Fe and 9% for K in the lake water. The pollution sources were designated by multivariate statistical analysis as being related to industrial and domestic waste, solid waste disposal, fertilisers and organic contamination from agricultural and natural sources. The water quality index (WQI) results were 22.3 to 721.3 for drinking, 13.9 to 86.2 for irrigation, 1.4 to 299.5 for livestock, 71.5 to 1754.4 for the textile industry, 20.7 to 237.9 for recreation and 64.6 to 1867.4 for aquatic life. The irrigation water quality index (IWQI) results were excellent for sodium adsorption ratio (SAR), and for the US salinity scale, all water samples fell into the medium salinity-low sodium category (C2-S1) in all seasons, except for all Chaqan River samples. The Tanjaro River sample in spring fell in the relatively high salinity-low sodium category (C3-S1), excellent and good for sodium percentage (Na%), suitable to moderate for permeability index (PI%), suitable to unsuitable for magnesium hazard percentage (MH%), suitable for Kelly Index (KI) and safe to unsuitable for residual sodium carbonates (RSC). The Sirwan River, Tanjaro River and Zmkan River took first to third place in both the annual average pollution share ratio and the discharge. While the Zalm River ranked fourth in discharge and fifth in pollution share ratio, the Chaqan River was the reverse. The highest pollution share ratio was 64.3 for the Sirwan River in summer, and the lowest was 0.7 for the Zalm River in autumn.

Degradation of Hydraulic System due to Wear Particles or Medium Test Dust

Contamination in hydraulic systems is the cause of 70% of failures. This study highlights the performance degradation caused by solid particle contamination of hydraulic components: hydraulic gear pump, 4/3 valve, and orbital motor. Experimental durability tests of components with wear particles and test dust are used to investigate the effects of accelerated wear caused by these two types of contaminants. Results show that oil contaminated with wear particles reduces the volumetric efficiency of the gear pump by 18% and the hydraulic valve by only 0.8%, while oil contaminated with test dust reduces the efficiency of the pump by 76% and the hydraulic valve by 0.9%. This research provides insights for accelerating hydraulic component testing to improve system reliability and longevity.

Experimental investigation of porous anode degradation of a molten carbonate fuel cell fed with direct fermentation product composed of bioethanol

The aim of the paper is to examine the performance of molten carbonate fuel cell, which is supplied with a raw bioethanol, i.e. bioethanol which origins directly from fruit fermentation, without pre-treatment of fermentation products. The composition of raw bioethanol was precisely determined and then the impact of raw bioethanol on the degradation of molten carbonate fuel cells was examined. Steam to carbon ratio of the biofuel has been determined as 5.7 (in comparison to stoichiometry of reaction) which allowed for estimation of hydrogen production during steam reforming process taking place in the anode channel. The results in the form of current-voltage curve was obtained and compared with the same fuel cell fed with pure hydrogen, while the amount of hydrogen was defined as identical with the one after steam reforming of biofuel taking place in the nickel anode channel. Relevant literature studies were focused on the purified fuel or examination of the impact of individual components. Our study proved carbon deposition is not a problem, however solid particles contamination in fermentation product makes it impossible to use fuel cell fueled with fermentation product for longer periods, and prior to supplying fuel cell the bioethanol purification is required. A raw biofuel with its impurities did not have any impact on the anode and current collector surface from physical point of view, but Electrochemical Impedance Spectroscopy analysis shows visible increase of ohmic loses.

Screening of chemical pulp, revisiting technology options, and the state‐of‐the‐art equipment—A critical review

AbstractScreening of pulp can be expressed as a process where solid contaminants are removed from a pulp slurry without an excessive loss of fibres of acceptable quality. The impurities originate from the feedstock, or they are generated during the transport, handling, storage, or pulping process. The most typical impurities include bark, fibre bundles or shives, knots, plastic, rubber, and sand. Moreover, there are also other objectives for screening, such as the improvement of the pulp quality, savings in bleaching chemical consumption, and protection of process equipment. In industrial applications, pulp screening is typically carried out with more than one screen for a more beneficial screening result. The pulp screening equipment can be divided into different types by the separation technique employed, such as atmospheric or pressurized screens, centrifugal screens, vibrating screens, etc. In addition, there are other types of related equipment that are common in the pulp screening process, such as knotters, refiners, and hydrocyclones. The main objective of this review is to discuss the advantages and disadvantages of modern screening equipment as well as introduce contemporary screening strategies for chemical pulp mills.

Sustainable corrosion-resistant superhydrophobic composite coating with strengthened robustness

In this paper, a superhydrophobic composite coating was developed employing epoxy resin (EP), polydimethylsiloxane (PDMS), and hexadecyltrimethoxysilane (HDTMS) functionalized Al2O3 nanoparticles as raw materials through a versatile and easily-scalable spray-coating technique. The water contact angle (WCA) and sliding angle (SA) of the designed superhydrophobic composite coating were 154.1 ± 0.7°and 3.5 ± 0.3°, respectively. The superhydrophobic composite coating features Cassie-Baxter phase contact, liquids repellency, anti-fouling, and self-cleaning properties for various liquid and solid contaminants. Compared with bare Q235 carbon steel, the charge transfer resistance (Rct) value of superhydrophobic composite coating immersed in the 3.5 wt. % NaCl solution can be remarkably enhanced by more than 7 orders of magnitudes with a corrosion inhibition efficiency of 99.99%. The coating maintain its superhydrophobicity, ultra-low adhesion force, and sustainable corrosion resistance even suffering 150 tape-peeling and 80 abrasion cycles. The improved durable mechanical robustness and interfacial bonding force can be attributed to the cross-linked and polymerized three-dimensional network micro-nano hierarchical structures formed by the combination of EP, PDMS, and embedded Al2O3@HDTMS nanoparticles. Besides, the accelerated salt-spray corrosion test (480 h) and atmospheric corrosion exposure (100 days) of the coating demonstrated superior anti-corrosion performance in both laboratory and real-world corrosive environments.

Investigation of Oil–Water Separation on an F-SiO2/TiO2-Based Superhydrophobic/Superoleophilic Surface: Experiment Evaluation and MD Simulation

Experiment evaluation and mechanism analysis of separation performance are crucial for oily wastewater treatment. In this work, a fluorinated superhydrophobic/superoleophilic (F-SHPB/SOPL) surface was fabricated on a steel mesh substrate by double depositions of SiO2-TiO2 nanoparticles for high-roughness improvement and composite modification of fluorine-alkyl groups for low-energy achievement. Measurements of SEM, XPS, FTIR, laser scanning confocal microscope (LSCM), and excitation-emission matrix (EEM) were carried out for surface property characterization. The oil-water separation performances at the prepared F-SHPB/SOPL surface were investigated from experimental and simulation aspects. Separation tests, flux tests, and anti-contamination tests were performed by experimental methods. The results indicated that the surface showed excellent separation efficiencies (>99.2%) for oil-water mixture and oil-in-water emulsion, high permeate flux (>3000 L·m-2·h-1) for organic oils, and perfect anti-pollution/self-cleaning capacity for liquid and solid contaminations. The interaction energies and interaction distances were measured by ab initio molecular dynamics simulation (AIMD) simulations. With lower interaction energy (Eoil = -456.52∼-1044.22 eV) than that of water molecules (Ewater = -172.73 eV) and shorter distance (Doil = 4.42∼5.13 Å) than that of water molecules (Dwater = 11.49 Å), oil molecules showed higher interaction stability than water molecules on the F-SHPB/SOPL surface. The calculation revealed the essence of the oil-water separation phenomenon. This work not only proposes the fabrication methodology of the SHPB/SOPL material but also elucidates the intermolecular interaction for oil-water separation. The results can provide a fundamental basis for separation operation and removal treatment in industrial and domestic applications.