Properties Of Liners Research Articles

Computational fluid dynamics and artificial neural networks for modelling lined irrigation canals with low‐density polyethylene and cement concrete liners

AbstractThis study numerically investigated the lining effect on the discharges and seepage losses of five reaches which belong to the El‐Sont Canal, Asyut, Egypt, using FLOW‐3D and Slide2 models, respectively. Two lining materials were considered, cement concrete (CC) and CC with low‐density polyethylene (LDPE) film. A cost analysis was performed to explore the feasibility of the proposed lining materials. Moreover, a parametric study was conducted by the Slide2 model to investigate the effect of canal geometry and liner properties on seepage losses. An artificial neural network (ANN) model was developed based on the Slide2 model scenarios to estimate the seepage losses from lined irrigation canals. The results showed that reach the discharge calculated from the FLOW‐3D model increased by 92%–97% and 149%–156%, while the calculated seepage losses from the Slide2 model decreased by 81%–87% and approximately 97% under CC and CC with LDPE film liners, respectively. Cost analysis revealed that the overall cost of CC with LDPE film was higher by 14% than CC. Relying on the importance of saving irrigation water and conveying water to the last reaches, CC with LDPE film is recommended for lining irrigation canals. A parametric study showed that the seepage losses were reduced by more than 96% when the ratio between liner and soil hydraulic conductivities was less than 0.01. A thick liner could maximally decrease the seepage losses by 68%, regardless of the canal geometry. As the developed ANN model showed a close agreement with the Slide2 results with coefficient of determination (R2) and mean squared error values of 0.99 and 0.05, respectively, the ANN model is recommended as a robust and rapid tool for estimating seepage losses from lined irrigation canals.

Predicting seepage losses from lined irrigation canals using machine learning models

IntroductionEfficient water resource management in irrigation systems relies on the accurate estimation of seepage loss from lined canals. This study utilized machine learning (ML) algorithms to tackle this challenge in seepage loss prediction.MethodsFirstly, seepage flow through irrigation canals was modeled numerically and experimentally using Slide2 and physical models, respectively. Then, the Slide2 model results were compared to the experimental tests. Thus, the model was used to conduct 600 simulation scenarios. A parametric analysis was performed to investigate the effect of canal geometry and liner properties on seepage loss. Based on the conducted scenarios, ML models were developed and evaluated to determine the best predictive model. The ML models included non-ensemble (regression-based, evolutionary, neural network) and ensemble models. Non-ensemble models (adaptive boosting, random forest, gradient boosting). There were four input ratios in these models: bed width to water depth, side slope, liner to soil hydraulic conductivity, and liner thickness to water depth. The output variable was the seepage loss ratio. Seven performance indices and k-fold cross-validation were employed to evaluate reliability and accuracy. Moreover, a sensitivity analysis was conducted to investigate the significance of each input in predicting seepage loss.Results and discussionThe findings revealed that the Artificial Neural Network (ANN) model was the most dependable predictor, achieving the highest determination-coefficient (R2) value of 0.997 and root-mean-square-error (RMSE) of 0.201. The eXtreme Gradient Boosting (XGBoost) followed the ANN model closely, which achieved an R2 of 0.996 and RMSE of 0.246. Sensitivity analysis showed that liner hydraulic conductivity is the most significant parameter, contributing 62% predictive importance, while the side slope has the lowest significance. In conclusion, this study presented efficient and cost-effective models for predicting seepage loss, eliminating the need for resource-intensive experimental or field investigations.

The Impact of Modified Metallic Nanoparticles on Thermomechanical Properties of PMMA Soft Liner

The Impact of Modified Metallic Nanoparticles on Thermomechanical Properties of PMMA Soft Liner

Geometrical modeling and experimental validation of 3D woven honeycomb fabric for lightweight aircrew helmet liner manufacturing

This research focused on the development of a honeycomb fabric by predicting the areal density suitable for aircrew helmet liner. The aim was to fulfill the requirements for the lightweight and mechanical properties of composite liner. The model was based on the structural characteristics of the preform, including the weave design and geometric parameters. The predicted areal density, based on varying yarn linear density and the number of picks in the free and bonded wall, was compared to experimental results and showed good agreement. A geometric model was derived to predict the areal density of 3D woven honeycomb preforms for producing the composite liner of aircrew helmet. The model was validated using experimental data from a variety of 3D woven honeycomb preforms, showing that it accurately predicts the areal density and can be used as a tool to design 3D woven honeycomb preforms for advanced composites.

Effect of leachate contamination in municipal solid waste on clay liner characteristics

Landfill leachate is generated as a consequence of water percolation through the solid waste, oxidation of the waste, and corrosion of the waste. Under-designed landfill sites allow the leachate to easily pass through the soil strata. To identify the effect of contaminants on the engineering properties of the clay liner, a pilot-scale lysimeter was developed. Experiments on two types of soils polluted with leachate were conducted which included silty clay and soil enhanced by chemical stabilization. Lime and silica fume are used as reactive barriers in landfill earthen liners. The leachate generated was monitored periodically and sampled for (pH, Electrical conductivity, Chemical oxygen demand, Chloride, Total dissolved solids, and total suspended solids). Lime (L), silica fume (SF), and lime-silica fume (L-SF) mix have been used for stabilizing soil. Three percentages were used for lime (2%, 4% and 6%) and three percentages were used for silica fume (3%, 5% and 7%) and the optimum percentage of silica fume (5%) was mixed with the proportions of lime. The optimum lime values are 4% from the research and 5% for silica fume. Soil samples were analyzed over a maturation period of 135 days for each run to identify the chemicals and their effect on the soil characteristics. The plasticity index of the stabilized soil continues to decline until it reaches 36% over the 135 days of the maturing period. Furthermore, an increase in silty clay soil hydraulic conductivity was observed from 3.3 × 10−6 cm/sec to 5 × 10−6 cm/sec at 135 days of maturation. Whereas there is a sharp decrease in hydraulic conductivity to achieve a maximum value in the stabilized soil (1.25 ×10−10 cm/sec). Based on laboratory test results, it can be concluded that soil stabilization can improve the geotechnical properties of landfill earthen liners due to pozzolanic reactions.

The Effect of Various Disinfection Methods on The Tensile Bond Strength of Soft Lining Material

Disinfection of dentures and resilient denture liners were preferred for cross-contamination treatment and better safety. Nevertheless, it has been found that these techniques affect the physical and mechanical properties of denture liners. Objective: To evaluate the impact of various disinfection methods on the tensile bond strength of acrylic soft liner. Material and Methods: 25 samples were made, then divided randomly into five groups (4 disinfection groups as well as a control group), after the daily disinfection procedure, distilled water was used to store the samples at room temperature. After 30 days, a universal testing device (Gester, China) was used to assess the tens ile bond strength. The machine applied force to the specim ens at a crosshead constant speed of 5 mm/minute until failure was recorded. Statistics software (SPSS) was used to analyze the measurements. Results: After 30 days of regular ex posure to different disinfection methods, a greater mean value for bond strength showed in the control group while the lesse r value was in the chlorhexidine group. No significant difference was found between the control and Protefix tablet groups. The sodium hypochlorite and microwave groups had no significant difference between them, but they were significantly different from the control, Protefix tablet, and chlorhexidine groups. the chlorhexidine group was significantly different from the control and other disinfected groups. Conclusion: All disinfected soft liners revealed a decrease i n tensile bond strength, which was not significant with the protefix cleansing tablet but significant with the chlorhexidine, sodium hypochlorite, and microwave regimes.

Effect of different microcapsule types on the wear mechanism of PTFE/aramid fiber composite liners

AbstractIn this study, three different methods based on vacuum adsorption, solvent volatilization, and Pickering emulsion were utilized to prepare microcapsules with the core material of PAO40 and the wall materials of SiO2, polysulfone (PSF), and PSF/SiO2 composites, respectively. PTFE/Kevlar fabric liners were modified by PAO40/SiO2 microcapsules (PSMS), PAO40/PSF microcapsules (PPMS), and PAO40/PSF/SiO2 microcapsules (PPSMS). The effect of microcapsules based on different wall materials on the tribological properties of liners was investigated by friction and wear tester under low‐speed and heavy‐load conditions. The anti‐friction and anti‐wear mechanisms of several microcapsule types on the liners were systematically investigated. The results showed that PPMS induced the most significant enhancement in anti‐friction properties of liners when compared to pure liner resulting in a 19.4% reduction in coefficient of friction (COF). PSMS was found to reveal much better wear resistance of liners, as evidenced by 75% increase in wear rate. PSMS and PPSMS not only release lubricating oil after the break of microcapsules under the friction action to lubricate, but also generate a cavity to store abrasive debris for liner wear reduction. Nonetheless, PPMS only released the oil onto the friction surfaces for lubrication. PSF as the microcapsule wall material could not contribute to the formation and promote wear resistance of transfer films. SiO2 as a microcapsule wall material participates in the formation and enhances the wear resistance of transfer films. The findings obtained are anticipated to improve the reliability and broaden the range of applications of liners in aerospace and other industrial fields.Highlights Three microcapsules all improve the tribological properties of the liners. Anti‐friction and wear‐resisting mechanism of three microcapsules in liners. SiO2 as wall material can increase the wear resistance of transfer films. PAO40 in microcapsules has antifriction effect at the friction interface.

Effect of spherical crown texturing and ionized sulfur infiltration on the tribological performance of piston-cylinder liner

In this study, the piston-cylinder liner was treated with single glow photoionization sulfurization of a cast aluminum alloy (AlSi10Mg), and the effect of the spherical crown texture on frictional properties of the piston-cylinder liner were investigated before and after the sulfurization treatment. The treated specimens were characterized and evaluated via microscopic morphological analysis, three-dimensional morphological analysis, X-ray diffraction (XRD), thin film diffraction, microhardness testing, and friction wear experiments. Fluent fluid analysis software was used to develop a flow field simulation model for the spherical crown texture. Results of the study showed that the average friction coefficients of the specimens treated with sulfur infiltration were all lower than those of untreated specimens, and the low friction coefficients were closely related to the laminar structure and weak interfacial bonding of the sulfur infiltration layer. The spherical crown structure effectively affected the stree distribution on surface of the specimens uniformly, which improved the bearing capacity and durability of the specimens, and the surface texture helped reduce the contact area and store the debris generated during the wear process, thus improving the friction performance. Mechanical stamping caused material aggregation on the edges of the weave, which increased the hardness of the edges and thus reduces the increase in wear around the weave. The surface microstructure of the specimens was effectively improved after sulfurization treatment, leading to higher wear resistance for the sulfurized specimens. Given the relative lack of research on the composite ionic sulfurization of piston-cylinder liner spherical crown texture at home and abroad, this experiment provides data support for this direction. The results provide beneficial clues for the design and optimization of the piston-cylinder liner spherical crown structure.

Modeling surface water and groundwater interactions for seepage losses estimation from unlined and lined canals

ABSTRACT This study utilized the Slide2 model to simulate surface water and groundwater interactions and estimate seepage losses from unlined and lined irrigation canals. Firstly, it was validated for an unlined canal passing through an unconfined, homogenous, and isotropic infinitely porous depth. Results revealed that the Slide2 model accurately simulated the seepage flow and estimated the seepage losses with R 2 = 0.99 and MAPE = 3.6%. Accordingly, the Slide2 model runs 54 scenarios to explore the effect of different groundwater table (GWT) locations below the canal berm, canal berm widths, and liner properties, such as liner hydraulic conductivity and thickness on the seepage losses from unlined and lined irrigation canals. The results concluded that when the GWT was above the canal surface water level (CSWL), the seepage losses tended to be lower, ensuing an inflow to the canal bed and inner side slope. Conversely, when the GWT was below the CSWL, the seepage losses tended to be higher, ensuing an outflow to the surrounding unsaturated soil. In contrast, the GWT did not affect seepage losses from lined canals. Also, a wider berm resulted in fewer seepage losses, while the canal berm was less effective for lined canals. In addition, the results proved the lining ability to reduce seepage losses. Thus, the average reduction percentage of the seepage losses for lined canal scenarios was 99.87%. Also, a thick liner could decrease the seepage losses maximally by 48.52%, regardless of the GWT location below the canal berm.

Enhanced mechanical and tribological performances of fabric liners with the intercalation of multi-level interphase

In this work, novel MXene nanosheet/Ag nanoparticles-polydopamine (PDA) hybrid nanostructured films were successfully produced and applied as interface layer for developing advanced Polytetrafluoroethylene (PTFE)/Polyimide (PI) fabric liners. The hybrid Ag/MXene-PDA layer uniformly deposited onto the fabric surface and interacted with resin matrix via physical locking and chemical bonding simultaneously, showing increments of 15.4 % and 56.8 % in tensile and interfacial bonding properties, respectively. Meanwhile, the thermal stability and heat conduction of fabric liners with the incorporation of hybrid layer presented effective enhancement due to the physical barrier and conduction channel. Furthermore, the abrasion resistance and lubrication properties of the fabric liners were also evidently enhanced after introducing the Ag/MXene interface phase, which could be attributed to the improved interfacial adhesion and formed high-quality tribofilm. This study proved the superiority of binary Ag/MXene films as interface layer, and provided the guidance for the structural design of fabric liners with excellent mechanical and tribological performances.

Effect of temperature variation on wear mechanism of liners modified by PAO40/SiO2 microcapsules

Self-lubircating liners are considered as critical bearing components, which show the primary applications in the aerospace field in a typical operation between − 50–163 ℃ to significantly influence the service life of liners. Therefore, the effect of ambient temperature (−40 to 160 °C) on tribological properties of liners with 6 wt% PAO40/SiO2 microcapsules friction chromium-plated shaft under 240 MPa was investigated. The results indicate that elevated temperature enhanced the formation of transfer films and associated tribochemical reaction that nonetheless could be restrained at the low temperature level. Wear depth and friction coefficient (COF) of the liner reached 0.052 mm and 0.039 respectively at 80 ℃, mainly due to the synergistic effect of friction reaction, high wear resistance of SiO2 and uniform density of the transfer film.

Study on dynamic mechanical properties of tungsten copper alloy and application of shaped charge

The tungsten-copper alloy liner has better performance than the copper liner. In order to better study the jet forming and penetration characteristics and dynamic mechanical properties of tungsten-copper alloy-shaped charge liner, this paper uses a multi-functional mechanical experimental machine and a Hopkinson bar device to carry out quasi-static tensile and dynamic impact tests, respectively, and fit the Johnson-Cook constitutive equation. The obtained parameters are used to carry out numerical simulations and compared with the experiment. The results show that the stress of the dynamic impact curve is higher than that of the quasi-static stress, and the strain rate strengthening effect is more obvious. There is an adiabatic temperature rise at the strain rate and an obvious thermal softening effect at different strain rates. At the highest strain rate, it shows an obvious strain rate strengthening effect and obvious plasticizing effect, and the tungsten-copper alloy has a certain sensitivity to strain rate. The precision of the Johnson-Cook constitutive model is higher, and it can better describe the plastic flow stress of tungsten-copper alloy at a high strain rate. When the parameters of the fitted Johnson-Cook model are used in the numerical simulation, the error between the numerical simulation and the actual is small. The obtained Johnson-Cook model and dynamic mechanical properties can help the follow-up study on the influencing factors of tungsten-copper jet forming and fracture, including the effect of material strength on injection instability, the integration of the shear band model with hydrodynamics, and the comparison of injection molding penetration with copper liners provide relevant data.

Effect of compaction water on strength and hydraulic properties of bentonite-based liner

The abundance of pond ash and its resemblance to natural sand encourages its use as a substitute for sand in sand–bentonite (SB) liner material. Compaction water content influences the geoengineering properties of cohesive soil to a great extent. Accordingly, the compaction, strength, permeability and shrinkage characteristics of both pond ash–bentonite (PAB) and SB mixes are investigated at standard and modified Proctor compaction energies at various water contents to support the recommendation of the PAB mixture as an alternative landfill liner. At similar compaction conditions, the PAB mix exhibits higher unconfined compressive strength (UCS) and hydraulic conductivity than the SB mix. The UCS values of mixes compacted on the dry side of optimum are higher than those of mixes compacted on the wet side. Dry-side compacted mixes exhibit a reduction in hydraulic conductivity with permeation time, whereas no substantial reduction in hydraulic conductivity is noticed for wet-side compacted mixes. Furthermore, the volumetric shrinkage of both PAB and SB mixes is within the permissible value of 4%, for a wide range of water variation from the dry to the wet side of optimum. The observed mechanical properties are correlated to the shape of coarse fraction particles and the corresponding microstructural arrangements of the compacted specimens.

Optimization on the diode laser joining process of Al2O3 liners

The effects of fillers width and energy density of laser on weld morphology were studied. The mullite filler with the quality ratio of 70wt.% Al2O3-30wt.% SiO2 was determined as the initial fillers for the joining of Al2O3 liners according to the crystalline phase of Al2O3 liners. The transient multiple physical model of diode laser joining Al2O3 ceramic liners was built by Multiphysics COMSOL, and the coupling of temperature and stress field was carried out. The thermodynamic properties of the Al2O3 liners and fillers were analyzed and tested. Numerical results showed that the increase of fillers width would effectively reduce the thermal stress of the joint. With the increase of the energy density, the temperature and thermal stress of the seam zone increased gradually. With the increase of laser joining heat input, weld penetration increased slowly and then sharply. The experimental results indicated that the weld zone free from pores and macro cracks can be formed with the fillers width of 3mm, laser power of 700W and welding speed of 1mm/s.

The Concept of WC-CrC-Ni Plasma-Sprayed Coating with the Addition of YSZ Nanopowder for Cylinder Liner Applications.

In the article, the new concept of plasma-sprayed coatings for the cylinder liner was presented. The new type of powder containing WC-CrC-Ni with a 5 and 10 wt. % addition of nano-YSZ powder was plasma-sprayed on aluminum 2017 alloy samples. The selection of optimal plasma-spraying parameters was made taking into account the thickness, porosity, and hardness of the coatings. For the coatings obtained according to the developed parameters, the analysis of their microstructure, chemical, and phase composition was performed. At the next stage, the friction coefficient of the developed coatings was tested and compared with the properties of a classic cast-iron cylinder liner. The obtained results suggest that the developed type of coating might be used for cylinder liner applications after a deeper friction analysis.

Investigation of the Leachate Effect on Permeability and Geotechnical Characteristics of Fine-Grained Soil Modified Using Nanoclay–Nanofiber Composites

Using low permeability soils in landfill liners is a guaranteed leachate control and prevents leakage which causes environmental pollution. In this matter, the application of new technologies such as nano provides more capable filters that are used for reducing leachate pollutants and modifying the geotechnical properties of liners. The presented study attempted to conduct experimental research on nanoclay–nanofiber composite usage to control landfill liner permeability and observe its impact on the geotechnical characteristics of liners which provide a strong barrel for leachate leakage prevention and increase the liner durability for crack generations. In this regard, a total of 120 different geotechnical experiments were performed on mixed improved fine-grained soil samples which were categorized into four groups including nanoclay additives, nanofiber additives, nanocomposite additives, and control samples (without additives). According to the experimental results, permeability decreased, and geotechnical properties (e.g., Atterberg limits, unconfined compressive strength, cohesion, and friction) were increased with increasing nanocomposite content in the soil.

Effect of Different Types of Denture Cleansers on Hardliner Surface Roughness


 Introduction: Hard liner is a denture relining material which can be used directly at the chairside in brief time. The characteristic of the hardliner is its susceptibility towards porosity which consequently resulting biofilm accumulation and Candida albicans colonization. Thus, there is a need for denture cleaning. Alkaline peroxide is a type of denture cleanser which is widely used, but it could affect the physical properties of hard liner. One of the traditional ingredients that have the potential to be used as an alternative to denture cleanser is cinnamon. Objective: This study aimed to evaluate the effect of different types of denture cleansers on the surface roughness of hard liner. Method: Twelve cylindrical hard liner specimens (15mm x 10mm, ASTM: D-2240 64T) were divided into three groups: group I (immersed in distilled water), group II (immersed in alkaline peroxide) and group III (immersed in 1.5% extract cinnamon). All specimens were soaked for 15 minutes/day for 7 days. Surface roughness was measured using surface roughness tester (Handysurf E-MC-S24B Japan). Data were analysed using one-way ANOVA and post hoc Bonferroni (α=0.05). Results: The highest average of surface roughness was shown on specimens immersed in alkaline peroxide, followed by specimens immersed in 1.5% cinnamon extract and distilled water, respectively. There were a significant difference in surface roughness values in all groups (p<0.05). Conclusion: There is an effect of type of denture cleanser on the surface hardness of hard liner.

Engineering Properties of Commercially Available Hermetic Storage Bag Liners

Highlights Fundamental engineering properties of hermetic bag liners were identified and measured to establish specifications for a new ASABE X657 standard for measurement and rating the performance of gas barrier liners in hermetic storage bags. Results showed strong evidence of differences in properties among six types of commercially available hermetic bag gas barrier liners (P<0.05). Critical gas barrier properties (OTR and WVTR) were measured to assess their ability to maintain initial conditions (“hermeticity”). Critical mechanical properties, such as impact failure weight, penetration resistance, and tear strength, were measured to determine their durability during handling and storage. Abstract. The impacts of hermetic storage bag technology on food security are well established. However, understanding the hermetic bag liner's mechanical and barrier properties with its useful life and efficacy are needed to ensure the continued successful adoption of this critically important storage technology to control biological activity. The goals of this study were to identify and quantify fundamental engineering properties as a basis for establishing an American Society of Agricultural and Biological Engineers (ASABE) engineering standard for testing and rating the hermeticity of gas barrier liners in storage bags for smallholder farmers. Six commercially available hermetic storage bag liners (AgroZ, Elite, PICS, GrainPro, Storezo, Zerofly) were evaluated for mechanical properties (tensile, impact, tear, penetration resistance) and barrier properties (oxygen transmission rate and water-vapor transmission rate) following American Society for Testing and Materials (ASTM) test methods. Results indicate significant differences (P< 0.05) in material properties among brands of storage bag liners. Values for oxygen and water vapor transmission rates were determined to ensure hermetic conditions can be achieved. Values for mechanical properties (yield and tensile strength, elongation, and toughness, tear strength, penetration resistance and impact failure weight) of gas barrier liners were quantified to ensure acceptable performance of hermetic storage bags. Keywords: Elongation, Hermetic storage, Hermetic storage bags, Impact failure weight, Oxygen Transmission Rates (OTR), Penetration resistance, Tear strength, Tensile strength, Toughness, Water Vapor Transmission Rate (WVTR), Yield strength.

Large eddy simulation study of the impact of an obstacle on cooling properties of a multiperforated liner

Large eddy simulations are performed to investigate the impact of a solid obstacle on the flow around a multiperforated plate typical of aeronautical combustion chambers. The reference configuration is a perforated plate with approximately 200 holes immersed between a cold vein and hot vein at a typical operating point of helicopter combustors. The micro-jet Reynolds number is of the order of 4000, while the blowing and momentum ratios are close to 4 and 8, respectively. A variant configuration is considered that features an additional cylindrical obstacle located in the cold vein and mimicking a spark plug. The study reveals that, downstream of the obstacle, the cooling effectiveness of the plate is reduced by approximately 40 % compared with the reference case, mainly due to the absence of perforation at the obstacle location. The mass flow rate within the holes in the wake produced by the obstacle is reduced by 7 %, which is likely to locally influence the plate cooling. The reduction is attributed to the wake's pressure loss and its impact on the discharge coefficient. Additionally, the cooling effectiveness outside the wake shows a 5 % increase that can be linked to the mass flow rate increase within corresponding holes.

Potential Therapeutic and Effective Properties of Soft Tissue Liners

Potential Therapeutic and Effective Properties of Soft Tissue Liners