Presence Of Distilled Water Research Articles

Multi-scale measurement of constitutive viscoelastic properties of bituminous composites considering moisture and deicing conditions

The use of salt and chemical deicers can cause significant damage to road infrastructures. This study investigates the impact of different deicers on the viscoelastic properties of mastic and asphalt mixtures, with a focus on characterizing their behavior at varying temperatures and loading frequencies. The samples were subjected to conditioning in solutions of distilled water, salt, Calcium Magnesium Acetate (CMA), and Potassium Acetate (KAc) at 60 °C for 96 h, followed by frequency sweep and dynamic modulus tests at different temperatures and loading frequencies. The results indicate that moisture conditioning with distilled water softens asphalt mixtures and mastic at low loading frequencies, while brine softens the former at low temperatures. Salt's high interaction with mixture aggregates cannot be ignored. CMA's effect on the fatigue behavior of mastic samples is highly dependent on loading frequency, while KAc increases stiffness at intermediate and high temperatures. All the deicers reduce resistance to rutting damage, with CMA having the most negative effect. Both the 2S2P1D and the generalized Maxwell model can well (R2 ≥ 0.90, Se/Sy ≤ 0.35) predict the viscoelastic properties of dry asphalt mixture. However, in the presence of distilled water and the deicers, asphalt mixture viscoelastic properties cannot be predicted according to asphalt mastic characteristics by implementing the homothety method which indicates different effects of distilled water and the deicers on various scales of bituminous composites.

Decolorization of p-nitrophenol and draft genome sequence of Pseudomonas sp. strain PNPG3: A preliminary report

Aim: To study decolorization (with concomitant depletion) of p-nitrophenol by a bacterial strain designated as PNPG3 and determination of draft genome sequence of the strain to understand its potential. Methodology: A comparative study of PNP’s decolorization (with concomitant removal) in three different test conditions was undertaken. The experiment was carried out in one-liter volume Schott Duran bottles. Genomic DNA was extracted and draft genome sequence was determined using Illumina HiSeqX platform. Raw reads were assembled and subjected to subsystem classification using several bioinformatics tools (RAST, PATRIC, and NCBI’s PGAP pipelines). The genome sequence was deposited at the NCBI Genome database and the strain PNPG3 was also deposited at MTCC, IMTECH, Chandigarh. Results: The bacterial strain PNPG3 could carry out decolorization with concomitant removal of PNP in all three sets of experiments, including one set, where only distilled water was used. The best decolorization (with concomitant PNP removal) capacity was recorded for set D (with Minimal Medium, MM; PNP, and free cells) followed by set E (MM, PNP, and immobilized cells) and set B (distilled water, PNP and free cells) conditions. The size of the draft genome sequence of the strain PNPG3 was 6,566,321 bp, with 62.26% GC contents. The genome had 6210 protein-coding sequences and 66 tRNA genes. The predictive presence of different types of proteases and siderophore receptors indicated its possible potential for industrial applications and plant growth-promoting activities. Interpretation: The bacterium Pseudomonas sp. strain PNPG3 has the capacity to decolorize p-nitrophenol even in presence of distilled water and it remains viable for up to twelve days. The genome sequence revealed that the strain harbored genes responsible for the metabolism of aromatic compounds, chemotaxis, protease, and siderophore receptors indicating the versatile nature of the strain. Key words: Decolorization, P-nitrophenol, Pseudomonas sp., RAST, Xenobiotic

Efficiency of phosphorus removal and recovery from wastewater using marl and travertine and their thermally treated forms

This paper presents a study under the dynamic conditions of marl and travertine materials and their thermal modifications (heated in a muffle furnace for 1 h: marl at 1000 °C, and travertine at 700 °C) and the material Polonite® in terms of phosphorus binding from municipal wastewater. The tests were carried out in filtration columns using hydraulic loads of 118.13, 312.56, and 640.45 dm3/(m2·h) until the ratio of effluent phosphorus concentration to initial phosphorus concentration reached 0.97. Materials with adsorbed phosphorus were subjected to the desorption process using distilled water and NaOH and HCl solutions, applying a hydraulic load of 312.56 dm3/(m2·h). To comprehensively assess the potential use of materials and their thermal modification in agriculture, leaching of elements from them was determined. The most favorable hydraulic load was 118.13 dm3/(m2·h), at which the sorbents achieved the best efficiency. The marl heated at 1000 °C was the most effective, achieving the longest working time of the bed with an efficiency greater than 98 %. The best reagent for desorbing phosphorus from the heated marl surface was a solution of 0.1 mol/L HCl, while for other materials a solution of NaOH 0.1 mol/L. Raw marl was the best at releasing phosphorus in the presence of distilled water, which combined with the results for the leaching of elements from this sorbent, indicate its potential use as a fertilizer or soil conditioner in agricultural production.

Accelerated laboratory evaluation of the effect of deicing condition on fracture characteristics of Silane-based modified asphalt mixtures

Winter maintenance of roads with inappropriate deicers causes much damage to road infrastructures. Researchers have always looked for suitable alternatives to salts or methods to increase the resistance of asphalt mixtures against chloride-based deicers. In this research, an accelerated laboratory method was used to investigate the effect of different deicers on nano-modified silane-based asphalt mixtures. Asphalt mixture samples were made by gyratory compaction method, and after core extraction, they were exposed to moisture and a solution of salt, Calcium Magnesium Acetate (CMA), and Potassium Acetate (KAc) for 96 h at 60 °C. Afterward, their fracture characteristics were measured at low and intermediate temperatures, and the results were statistically analyzed using two-way ANOVA and Tukey test. Statistical analysis showed that although there is no significant difference between the fracture toughness of asphalt mixtures at 0 °C in the presence of distilled water, CMA, and KAc, the reduction in the fracture toughness of samples is much greater in the presence of brine solution so that the fracture toughness of this mixture experienced a 30% reduction compared to the dry sample. Submerging the specimens in the brine solution reduces the resistance of asphalt mixture to cracking at both low and intermediate temperatures, while KAc has the least damaging effect on the fracture toughness of asphalt mixtures. Based on visual inspection and test results, CMA causes additional stress and cracking in asphalt specimens and reduces their resistance to fracture at intermediate temperatures. The silane-based anti-stripper, maintains the fracture toughness of asphalt mixture samples submerged in distilled water and the deicers at 0 °C at almost constant levels but reduces the Jc parameter in all samples. Also, conditioning in the deicers has a greater effect than binder type on the fracture toughness of asphalt mixtures at 0 °C. Besides, there is a strong interaction between binder and deicer type on stress intensity factor, K1c, of asphalt mixtures.

Sorption and transport characteristics of europium on sandy soils

Radioactive europium can be released as a fission product during nuclear incidents and pose a threat to the human and surrounding environment because of its biological activity and long decay half-lives. For safe design issues and human health protection demands in construction of the planned nuclear power plants (NPPs) at Al-Dabaa site, it is necessary to study the sorption and transport of different radionuclides as europium within the selected area for predicting their fate at any crisis. Many soil samples were collected from different locations at the area selected along the northwestern coast of Egypt. The samples were transported to the laboratory, preserved, and characterized using X-Ray fluorescence (XRF), Fourier transform infrared spectroscopy (FT–IR), and X-Ray diffraction (XRD). Experiments were performed to study the sorption and transport kinetics of Eu(III) ions on two sandy soil samples from the collected ones. The effect of different parameters (e.g. contact time, pH, initial europium concentration, and temperature) on the sorption behavior europium was explored in a static condition. The maximum sorption capacity was determined and found to be 3.4 and 7.0 mg g−1 for sorption of Eu(III) ions onto soil-1 and soil-2, respectively. Different models were applied to assess the sorption of europium onto the surface of the investigated soils. Data confirmed that Eu retention was attained through a chemisorption process. Further, the thermodynamic parameters were determined and their values confirmed the endothermic nature of the sorption process. The transport of europium radionuclides, with groundwater, through homogeneous porous media with uniform one-dimensional flow in the geosphere was processed and the relative migration velocity was determined in presence of both distilled and seawater media. The transport of Eu(III) radionuclides was higher in presence of seawater than that in presence of distilled water by about two order of magnitude. This obviously clarified the effect of seawater in accelerating the transport of radionuclides with groundwater in the geosphere of studied area. The role of different competing ions have various valances on the relative migration velocity was explored. Further, the time required for studied radionuclides to reach Mediterranean Sea was determined.

Growth, geometrical analysis, FMO, MEP UV–vis, nonlinear optical and antibacterial properties of pure and 2-furoic acid doped Guanidinium carbonate single crystal

In the presence of distilled water, the adaption of the slow evaporation solution growth approach resulted in the successful development of single crystals of Pure and doped GC (FAGC). The cell characteristics of the produced FAGC crystals were investigated using single-crystal X-ray diffraction analysis. The theoretical analysis was carried out using the DFT method, and the HOMO-LUMO energy band difference was estimated. The Molecular optimized geometry, MEP and HOMO-LUMO energy distance were computed using the B3LYP level of theory using a 6-31G (d,p) basis set. The FT-IR spectrum probes the modes of vibration of various functional groups in pure and doped GC (FAGC) crystals. According to UV–visible NIR transmittance experiments, the formed crystal exhibits a high transmittance in the whole visible range. The relative SHG efficiency of pure and doped crystals (FAGC) was carried out by the Kurtz perry technique. The Antibacterial activity demonstrates that both the pure and the dopant have antibacterial action against dangerous microorganisms.

Analysis of a Vegetable Oil Performance in a Milling Process by MQL Lubrication.

In this work, we carried out a comparison between the dry machining of an aluminum block with conventional cutting oil and a block with vegetable oil. The two oils had different flow rates. Using the Taguchi method, it was possible to determine the matrices for optimizing the best parameters for each group of tests. Then, we studied the utility of using vegetable oil as a cutting lubricant. We found that the vegetable oil studied in this work had good properties in terms of reducing cutting temperatures but was less effective than conventional cutting oil in reducing the surface roughness of the machined part. Tribological tests were carried out to understand the influence of the selected lubricants in reducing friction and wear. After the sliding experiments, which were performed without lubrication in the presence of the same lubricants that were used in the machining tests and in the presence of distilled water, we concluded that vegetable oil has satisfactory lubricating properties that are similar to those of the conventional cutting fluid, indicating a potential for consideration as an effective alternative to the conventional cutting fluid, with economic, environmental, and health advantages.

Engineering of Nanostructured Carbon Catalyst Supports for the Continuous Reduction of Bromate in Drinking Water

Recent works in the development of nanostructured catalysts for bromate reduction in drinking water under hydrogen have highlighted the importance of the properties of the metallic phase support in their overall performance. Since most works in catalyst development are carried out in powder form, there is an overlooked gap in the correlation between catalyst support properties and performance in typical continuous applications such as fixed bed reactors. In this work, it is shown that the mechanical modification of commercially available carbon nanotubes, one of the most promising supports, can significantly enhance the activity of the catalytic system when tested in a stirred tank reactor, but upon transition to a fixed bed reactor, the formation of preferential pathways for the liquid flow and high pressure drops were observed. This effect could be minimized by the addition of an inert filler to increase the bed porosity; however, the improvement in catalytic performance when compared with the as-received support material was not retained. The operation of the continuous catalytic system was then optimized using a 1 wt.% Pd catalyst supported on the as-received carbon nanotubes. Effluent and hydrogen flow rates as well as catalyst loadings were systematically optimized to find an efficient set of parameters for the operation of the system, regarding its catalytic performance, capacity to treat large effluent flows, and minimization of catalyst and hydrogen requirements. Experiments carried out in the presence of distilled water as a reaction medium demonstrate that bromate can be efficiently removed from the liquid phase, whereas when using a real water matrix, a tendency for the deactivation of the catalyst over time was more apparent throughout 200 flow passages over the catalytic bed, which was mostly attributed to the competitive adsorption of inorganic matter on the catalyst active centers, or the formation of mineral deposits blocking access to the catalyst.

Analysis of friction and wear processes in an innovative spine stabilization system. Part 1. A study of static and kinetic friction of a metal rod-polymer cord friction joint

Purpose: This analysis is the first part of research that aims to develop a model of the tribological wear of PE-UHMW cord – biometal rod combination. This type of sliding joint is applied in spine stabilization systems that enable the treatment of early-onset idiopathic scoliosis. Methods: The friction tests included force measurements, followed by the determination of static and kinetic friction coefficients as a function of the number of the performed movement cycles, and static friction coefficient with regards to the string tension force FN in the range of 50–300 N. Additionally, the surface roughness and microscopic observations of the metal rods were made. The friction measurements were carried out at a stabilized temperature T = 38 °C in the presence of distilled water and acidic sodium lactate. Results: The measurements confirmed the impact of both the number of completed movement cycles and the value of the force loaded on the cord on the static friction coefficient. Similar values of kinetic friction force occur for the pairs with the titanium alloys rods, as well as for the pairs with the steel and CoCr rod. The type of lubricant affected the obtained measurement results unevenly: (Ti6Al4V and Ti6Al7Nb – slight impact, steel 316L and CoCrMo – large impact). During microscopic observations, numerous wear products, were visible, including harder than the base material large conglomerates. Conclusions: Susceptibility of polymer fibres results in its increased resistance to wear, but it can be also combined with an increase in wear of the surface of the metal rod.

Polyaniline Thin Film Prepared by Electrochemical Polymerization Method

Polyaniline (PANI) slim film was set up by electrochemical polymerization strategy at room temperature in a standard three-electrode cell from (0.1M) aniline monomer and (0,5M) from Sulfuric acid in the presence of distilled water. The development of PANI film was portrayed by Voltammetric studies, SEM, XRD, and FTIR. Voltammetric studies were performed in 0.5 M acidic aqueous solutions using H2SO4. The XRD design demonstrated that the diffraction top at 2θ = (30˚). The FTIR spectroscopy spectra give particular and unmistakable bonds at 3500, 1572.52, 1302.53, 831.98, and 592.85 cm-1.

A new liquid sensor based on a piezoelectric resonator with a radial electric field

The possibility of development a liquid sensor based on a piezoelectric resonator with radial concentric electrodes is shown. The specified resonator has a large number of resonance peaks corresponding to different vibrational modes. The influence of two types of liquid container with distilled water on the resonance characteristics of these vibrational modes is experimentally investigated. As a result, the optimal type of container and two vibrational modes with frequencies of 0.128 and 0.317 MHz were selected, which retain acceptable Q-factors in the presence of distilled water. The dependences of the resonance frequency and the maximum value of the real part of the electrical impedance of these resonance peaks on the conductivity of the liquid were measured. It has been found that with an increase in the conductivity of the liquid, the resonance frequency of the parallel resonance initially remains practically unchanged, but after reaching a certain value of the conductivity of water, it decreases for both resonances. In this case, the maximum value of the real part of the electrical impedance first decreases, reaches a minimum, and then increases in all cases. It is shown that using these dependences as calibration curves, one can unambiguously determine the conductivity of a liquid in the range of 45–5000 μS/cm.

Removal of zinc, lead and nickel from contaminated soil by electro-kinetic technology under the influence of washing and buoyance forces with different purging solutions

ABSTRACT The effects of the washing process, purging solution, and buoyance force (inclined topography action) on the effectivity of the electro-kinetic method used to remediate of a silty clay loam and natural soils contaminated with Zn, Pb and/or Ni were investigated by applying 12 different experiments. The results revealed that the washing process and buoyance force can cause a small increase in the Zn removal efficiency (≤ 31%) when compared with non-washing approach using distilled water purging solution. Using 0.1 M of EDTA solution for the soil contaminated with listed metals in combination with washing can lead to significant increase in the removal efficiencies with percentages not greater than 58.4, 60.68 or 42.8%, respectively. In the presence of EDTA, however, the majority of metals passed through the soil media to the anode area. In contrast, these metals are accumulated near the cathodic region in the presence of distilled water. The results demonstrated that the buoyance force (resulted from inclination angle of 30°) with EDTA had adverse influence on the metal profile along the treated soil. Finally, the results certified that EDTA in electro-kinetic process coupled with soil washing is a new hybrid technique which achieved Pb removal efficiency from natural soil reached to 58% by improving the solubilization and transport of metal ions.

The theoretical adhesion of Pseudomonas aeruginosa and Escherichia coli on some plumbing materials in presence of distilled water or tap water.

The main aim of this work was to determine the most appropriate materials for the installation of a water system according to the characteristics of the water that passes through it. To this end, we conducted an investigation of the effect of two types of water (SDW: sterile distilled water and STW: sterile tap water) on the properties of bacterial surfaces and the theoretical adhesion of two bacteria (Pseudomonas aeruginosa and Escherichia coli) on six plumbing materials. Contact angle measurements were used to determine the surface energies of bacteria and materials. XDLVO theory was used to estimate the interactions between bacteria and plumbing materials. The results showed that water had a clear impact on the electron donor character and the hydrophobicity of the bacterial surfaces. Also, the predictive adhesion showed that all tested materials could be colonized by P. aeruginosa and E. coli ([Formula: see text]<0). However, colonization became thermodynamically less favorable or unfavorable (increase in [Formula: see text] values) with SDW and STW, respectively. Finally, the results suggest that the choice of the most suitable material for a drinking water installation is related to the quality of the water itself.

Experimental Analysis and Optimization of EDM Parameters on HcHcr Steel in Context with Different Electrodes and Dielectric Fluids Using Hybrid Taguchi-Based PCA-Utility and CRITIC-Utility Approaches

Industries demand stringent requirements towards economical machining without hindering the surface quality while cutting high carbon high chromium (HcHcr) steel. Electrical discharge machining (EDM) of HcHcr steel aims at reducing machining cost (i.e., maximize material removal rate (MRR) and minimize tool wear rate (TWR)) with good surface quality (i.e., minimize surface roughness (SR)). A comparative study was carried out on EDM of HcHcr D2 steel (DIN EN ISO 4957) by applying Taguchi L18 experimental design considering different electrode materials (copper, graphite, and brass), dielectric fluids (distilled water and kerosene), peak current, and pulse-on-time. The process performances were analyzed with respect to material removal rate, surface roughness, and tool wear rate. Pareto analysis of variance was employed to estimate the significance of the process variables and their optimal levels for achieving lower SR and TWR and higher MRR. Hybrid Taguchi-CRITIC-Utility and Taguchi-PCA-Utility methods were implemented to determine the optimal EDM parameters. Higher MRR of 0.0632 g/min and lower SR of 1.68 µm and TWR of 0.012 g/min was attained by graphite electrode in presence of distilled water as dielectric fluid compared to the brass and copper. Additionally, a metallographic analysis was carried out to study the surface integrity on the machined surfaces. Micrographic analysis of the optimal conditions showed lower surface roughness and fewer imperfections (lesser impression, waviness surface, and micro-cracks) compared to worst conditions.

Experimental and simulation study of the tensile strength of wet carbonate rocks using the Brazilian Test

Mechanical behavior of rocks would have substantial implications for different operations from fluid injection and hydraulic fracturing in hydrocarbon reservoirs to underground carbon dioxide storage in the crust of the earth. In all of these operations, restricting the undesired seismicity events and preserving the integrity of formations is a crucial subject that enforces engineers to evaluate the mechanical behaviors of constituent rocks and predict the formation response. Tensile strength is an important factor for maintaining caprock and reservoir formation from induced tensile cracking which can be influenced by the pore fluid. This paper focuses on the tensile strength of carbonate rock, as an important reservoir rock, in the presence of seawater, as a common injection fluid candidate for enhanced oil recovery objectives. For this purpose, twelve dolomite samples from the Asmari-Jahrum Formation outcrop in Fars province, Iran, were prepared for performing tensile tests. Also for a thorough comparison, sample properties, fluid contents, digital image correlation measurements, and a finite element simulation have been investigated. The experimental results showed a noticeable reduction in the tensile strength of dolomite samples in the presence of distilled water and seawater. In comparison with a dry sample though, a reduction of 16% tensile strength for a seawater saturated sample was observed for similar samples. Among the various mechanisms, which are reported in the open literature, the hydration force seems to be the main reason for the tensile strength reduction and this conclusion was examined by measuring the mass of vaporized adsorbed water on the powder of the same dolomite sample. In addition by testing flooded samples, the impact of flow on the tensile strength was examined. For both cases of seawater and distilled water flooding, the samples which were placed in the outlet zone during the flooding showed lower tensile strength. Moreover, simulation results confirmed the similarity of the weakening trend and impact of seawater.

Pulsed Laser Ablation Produced Copper Nanoparticles (CUO NPS): The Influence of Time

Copper nanoparticles were synthesized using laser ablation method by the reduction of copper plate in the presence of distilled water. Effects of time as the laser hits on the copper target were increased, the amount of Cu NPs in the distilled water also increased. EDAX confirms the existence of Cu NPs. The metallic nanoparticles have a unique optical property known as Surface Plasmon Resonance (SPR) which can be utilized to enhance the light harvesting performance in many applications. The noble metals of copper have the ability to support surface plasmon resonance which can be used to enhance the efficiency of any device.

Mechanical Assisted Modification of Halloysite Nano Clay: Characterization and Its Effect on Mechanical Properties of Halloysite-Epoxy Nano Composites

Modificationof Halloysite nano clay has been done using 3-aminopropyltriethoxysilane in the presence of distilled water as solvent media. Untreated and modified nano clay was characterized by Powder X-ray diffractometer (PXRD), Scanning Electron Microscope (SEM), Fourier Transform Infrared Spectroscopy (FT-IR). Functionalization of Halloysite nano clay is also strongly affected the morphological parameters and enabling the application in epoxy nano composite. However, the influence of modified clay concentration on the mechanical properties of epoxy/nanoclay composites, with different concentrations (2%, 3%, 4% and 5%) of nano clay in the epoxy resin was investigated. Experimental results showed that the mechanical properties of epoxy were improved upto 4 wt% of HNP’s, evidently because of the loading of modified clay. The tensile strength, tensile Modulus, flexural strength, flexural modulusand fracture toughness of the nanocomposites increased by 13%, 17%, 9%, 14%and 27% respectivelythis demonstrated that the composites were strengthened.

Polyacrylamide hydrogel application in sand control with compressive strength testing

Sand production is one of the major problems in sandstone reservoirs. Different mechanical and chemical methods have been proposed to control sand production. In this paper, we propose a chemical method based on using polyacrylamide/chromium triacetate hydrogel to investigate sand production in a synthetic sandpack system. To this end, a series of bulk experiments including the bottle test and rheological analysis along with compression tests were conducted. Experimental results indicated that the compressive strength of the sandpack was increased as much as 30 times by injecting 0.5 pore volume of hydrogel. Also, it was found that the increases in cross-linker and polymer concentrations exhibited a positive impact on the compressive strength of the sandpack, mostly by cross-linker concentration (48 psi). Hydrogel with a higher value of cross-linker could retain its viscoelastic properties against the strain which was a maximum of 122% for 0.5 weight ratio of cross-linker/polymer. The presence of salts, in particular divalent cations, has a detrimental effect on the hydrogel stability. The maximum strain value applied on hydrogel in the presence of CaCl2 was only about 201% as compared to 1010% in the presence of distilled water. Finally, thermogravimetric analysis and its derivative showed that the hydrogel could retain its structure up to 300 °C. The results of this study revealed the potential application of the hydrogel to control sand production.

Protective role of exogenous phytohormones on redox status in pea seedlings under copper stress

The present work aims to provide insight on the role of phytohormone application in developing efficient practical defense strategies to improve plants tolerance under heavy metal contamination. For this purpose, pea (Pisum sativum L.) seeds were germinated in an aqueous solution of 200μM CuCl2 up to the 3rd day and then continued to germinate in the presence of distilled water (stress cessation) or were subjected to following combinations: Cu+1μM IAA and Cu+1μM GA3 for 3 additional days. The results showed that copper excess induced oxidative stress in germinating seeds, which resulted in changes of the redox state of glutathione and cysteine, and proteomics revealed Cu-induced modifications of thiols (SH) and carbonyls (CO) (indicators of protein oxidation). However, application of IAA or GA3 in the germination medium after 3days of Cu exposure alleviated toxicity on seedlings, despite the persistence of Cu up to 6th day. This improving effect seems to be mediated by a cell Cu accumulation decrease and a protein reduced status recovery, since phytohormones modulate thioredoxin/ferredoxin systems in favor of protecting proteins against oxidation. In addition, an IAA and GA3 protective effect was evidenced by a cellular homeostasis amelioration resulting from the balance conservation between the regeneration and consumption processes of glutathione and cysteine reduced forms. The exogenous effectors also induced modifications of profiles of SH and CO, suggesting changes in the regulation and expression of proteins that could be involved in defense mechanism against Cu stress.

Effect of debris size on the reciprocating sliding wear of aluminium

The literature is controversial in relation to the influence of wear debris on tribological behaviour. Some works have shown that the presence of debris is fundamental to the formation of a protective tribolayer, thus reducing friction, whereas others showed that the presence of wear debris could contribute to increase friction coefficient due to the energy spent dragging them into the contact. This work aims to study the influence of the presence of wear debris, simulated by Al2O3 particles, on the tribological behaviour of an aluminium-steel pair under reciprocating sliding contact. Special emphasis is given to the particle size (0.05 µm, 0.1 µm, 1 µm and 10 µm). The particles were dispersed in distilled water (2 wt.%) as the source of debris. Reference tests were carried out solely in the presence of distilled water. The addition of alumina particles contributed to a significant reduction in friction coefficient, in particular for the largest particles (diameter ϕ=10 µm). When the larger particles were added, it was possible to observe the formation of a tribolayer on the sample surface leading to a gain of mass. In opposition, the wear rate of the counter body increased when large particles were added and the wear tracks showed strong evidence of abrasive wear. This suggests that hard and large wear debris, incorporated in the tribolayer formed on the samples, can act as hard protuberances, leading to abrasive wear of the counterbodies. When small particles were added, friction was still reduced when compared with the reference test, but the reduction of the friction coefficient was less significant. Small particles reduced the steel counter body wear rate and did not affect significantly the wear rate of the aluminium samples. It is proposed that small debris can get entrapped in the surface irregularities of the specimens and therefore participate less in the formation of the tribolayers.