Durability Studies Research Articles

Scalable, Interfacially Synthesized, Covalent-Organic Framework (COF)-Based Thin-Film Composite (TFC) Hollow Fiber Membranes for Organic Solvent Nanofiltration (OSN).

Covalent organic frameworks have great potential for energy-efficient molecular sieving-based separation. However, it remains challenging to implement COFs as an alternative membrane material due to the lack of a scalable and cost-effective fabrication mechanism. This work depicts a new method for fabricating a scalable in situ COF hollow fiber (HF) membrane by an interfacial polymerization (IP) approach at room temperature. The 2D COF film was constructed on a polyacrylonitrile HF substrate using aldehyde (1,3,5-trimethylphloroglucinol, Tp) and amine (4,4'-azodianiline (Azo) and 4,4',4″-(1,3,5-triazine- 2,4,6-triyl) trianiline (Tta)) as precursors. The COF membrane on the PAN substrate showed 99% rejection of Direct red-80 with remarkable solvent permeance. The rejection analysis revealed that the structural aspects of the solute molecule play a major role in rejection rather than the molecular weight. We further optimized the precursor concentrations to improve the permeation performance of the resulting membrane. The durability study reveals excellent stability of the membrane toward organic solvents. This study also demonstrated the easy scalability of the membrane fabrication approach. The approach was further extrapolated to fabricate a cation-based COF membrane. These charged membranes exhibited an enhanced rejection performance. Finally, this approach can facilitate industrially challenging molecular sieving applications using COF-based membranes.

NMR-based analysis of fractal characteristics of the pore structure of fully aeolian sand concrete under carbonation-dry-wet cycles

The evolution law of the pore structure of concrete is important for the study of concrete durability. To study the quantitative relationship between pore structure and macroscopic mechanics of aeolian sand concrete(ASC) under carbonation-dry-wet cycle(DWCs), the fractal characteristics of ASC under carbonation DWCs were analyzed by means of nuclear magnetic resonance(NMR) technology. The results showed that the carbonization product CaCO3 filled the pores and the compressive strength of ASC increased as the carbonization time increasing. When the DWCs was 0 times, the compressive strength of C1 and C2 groups increased by 9% and 13.6%, respectively, compared with C0. The compressive strength of C0 and C1 groups reached the maximum value when the DWCs was 40 times, while the C2 group reached the maximum value when the DWCs was 20 times. Compared with C0, the compressive strength of C1 and C2 increased by only 4% and 6%, respectively, after 100 DWCs. The fractal dimension Dmax reflected the proportion of harmless and multiple harmful pores in the damaged ASC. The fractal dimension Dmax was proportional to the proportion of harmless pores, and the correlation coefficient was 0.9303. The fractal dimension Dmax was inversely proportional to the proportion of harmful pores, and the correlation coefficient was 0.9565. The macroscopic mechanical properties were mainly affected by harmless pores and harmful pores, while the influence of less harmful pores and harmful pores was weak. This study will provide a theoretical justification for the use of ASC in practical engineering.

Selection of Either (Fly Ash, Rubber And Rice Husk) Material for Rigid Pavement: Review

Abstract: Road transportation plays a crucial role in India's economic development, providing cost-effective, accessible, and adaptable means of transportation for both passengers and freight. Pavement, as a key component of highway design, must withstand vehicular loads and foot traffic while ensuring safe and efficient movement. This paper reviews existing literature on pavement materials, focusing on sustainable alternatives such as fly ash-based geopolymers, basalt fiber-reinforced concrete, and asphalt mixtures incorporating recycled aggregates and rubber. Additionally, it proposes the combination of rice husk and crumb rubber in concrete as a sustainable approach for pavement construction. The study aims to evaluate the mechanical properties of concrete with partial material replacements through experimental investigation. By addressing gaps in durability studies, comparative analysis, and non-destructive testing, this research seeks to provide valuable insights into the feasibility and sustainability of utilizing waste materials in concrete production. Ultimately, it aims to contribute to advancing sustainable practices in the construction industry and addressing the challenge of waste accumulation.

Study of Mechanics and Durability of Non-Spontaneous Combustion Coal Gangue Coarse-Aggregate High-Performance Concrete.

The coal gangue coarse-aggregate content in ordinary concrete should not be too large. In order to further improve the utilization rate of coal gangue coarse aggregate, this study used the principle of "strong wrapped weak" to prepare high-performance concrete. This study considered four factors, namely, water-binder (W/B) ratios, non-spontaneous combustion coal gangue (NCCG) coarse-aggregate contents, fly ash-slag mass ratios, and silica fume coating to prepare high-performance concrete. The workability, mechanical, and durability properties were studied, and the changes in the interfacial transition zone (ITZ) of concrete before and after sulfate attack and freeze-thaw cycles were analyzed based on the SEM test. The life prediction of NCCG coarse-aggregate high-performance concrete was carried out based on the grey system GM(1,1) prediction model. The results show that the NCCG coarse-aggregate contents have the greatest effect on compressive strength, sulfate resistance, and frost resistance. The W/B ratio has the greatest effect on the anti-carbonization properties. Fly ash-slag mixing can obtain better durability. Considering the effect on the design service life of high-performance concrete, NCCG coarse aggregate is used to prepare high-performance concrete in North China, and the recommended content is 60%; in the Northwest and Northeast regions, the recommended content is 45%. This study provides a basis for the preparation of high-performance concrete with NCCG coarse aggregate.

Strength prediction of modified self-compacting concrete using response surface method

AbstractThis study highlights the effectiveness of the response surface method in predicting the properties of hardened concrete containing spent foundry sand and manufactured-sand. In current research, different mix proportions are prepared with spent foundry sand and manufactured-sand as partial replacements for fine aggregate. The workability, strength, and durability studies are conducted on all concrete mixes. The test results confirm that the inclusion of 20% of spent foundry sand is optimum for enhancing the strength and durability. Also, the inclusion of 20% of spent foundry sand in manufactured-sand concrete also possesses optimum results in strength and durability. Further, the response surface method has been employed to develop a model for compressive strength prediction. The R-squared and residual sum of squares of error for the compressive strength model were 0.9863 and 2.345, which confirms the goodness of the fit.

Study of durability and mechanical properties for utilization of cupola slag as a coarse aggregate in M20 grade green concrete

Cupola slag is an industrial waste generated from cupola furnaces during cast iron production. The disposal of cupola slag is a matter of burden for the manufacturers of casting industry. This experimental study aims to reuse cupola furnace slag (CFS) in the construction industry, developing a novel way of solid waste management. In the M20 grade concrete, CFS is used as coarse aggregate (CA), partially replaced by 0–50 wt % in the step of 10 wt %. The mechanical and durability properties of the CFS-based concrete were examined after the required days of curing. The experimental result exposed that the dry density decreases with the increased weight percent of CFS in concrete. The cast samples with up to 40 wt% partial replacement of CFS effectively meet the requirements for the M20 grade of concrete in terms of compressive strength. A similar trend for the split tensile strength was observed, like the compressive strength. Durability test results reveal that water penetration depth increases with increased CFS weight percent in concrete. Moreover, in the case of rapid chloride penetration test, chloride ions penetration is decreased with the increase of CFS weight percent in concrete. FESEM, EDS and XRD were used to examine the microstructure, elemental mapping and phase analysis of the CFS-based concrete. According to the investigation, CFS is a sustainable material that works well as a partial replacement for natural CA in concrete.

Durability studies and microstructure analysis on roller compacted concrete with sodium bentonite as special admixture and crusher dust as fine aggregate

Durability studies and microstructure analysis on roller compacted concrete with sodium bentonite as special admixture and crusher dust as fine aggregate

A Comprehensive Review of Total Hip Arthroplasty Outcomes in Post-traumatic Hip Arthritis: Insights and Perspectives.

Post-traumatic hip arthritis presents a challenging condition characterized by degenerative changes in the hip joint following traumatic injury. Total hip arthroplasty (THA) is a cornerstone in managing this condition, offering significant pain relief, functional improvement, and enhanced quality of life. This comprehensive review aims to synthesize existing literature to elucidate the outcomes of THA in post-traumatic hip arthritis, exploring factors influencing surgical success and identifying areas for further research. Key findings reveal favourable clinical outcomes associated with THA, though considerations such as patient characteristics, surgical techniques, and implant selection impact outcomes. Implications for clinical practice underscore the importance of tailored preoperative assessment and ongoing advancements in surgical approaches and implant technology. Furthermore, opportunities for future research lie in long-term durability studies, patient-reported outcomes assessment, and exploration of innovative surgical techniques. Overall, THA emerges as a promising intervention for post-traumatic hip arthritis, yet continual refinement through research and innovation remains imperative to optimize patient care in this population.

Durability Studies of Conventional Cement Concrete and Geopolymer Concrete

The service life of structural members is significantly impacted by the durability of the concrete and that they are made of. The embedded reinforcing steel in durable concrete is protected from corrosion, and the possibility of concrete spalling in the concrete as a result of chemical attack is reduced. This study investigates the effectiveness of geopolymer concretes prepared using fly ash or a mixture of fly ash and slag (SLG). The performance of OPC concrete is likewise evaluated for comparing the durability of geopolymer concretes. This is done in order to compare the two types of concrete. All of the prepared specimens were submerged in theee types of distinct solutions up to 9 months. Four different types of solutions are (i) sodium chloride with 5% concentration, (ii) sodium sulphate 5% concentration, (iii) combination of magnesium sulphate with sodium sulphate with 5% concentration both, and sulphuric acid 3% concentration. The variation in properties were evaluated throughout the duration of the exposure period. According to the findings, it has been demonstrated that Na2SO4 (sodium sulphate) has the most significant effect on the geopolymer concretes, whereas sulphuric acid has the greatest potential to break down OPC concrete. With the effect of sulfuric acid, the strength reduction was 26.57% for OPC concrete and where as for flyash & SLG concretes it is 10.87% & 7.26% respectively. According to the findings, the durability performance of geopolymer concrete is, in general, better to that of cement concrete.

Mechanical and Durability Studies about the use of Municipal Solid Waste Landfill in Concrete

The best way to keep the required format of the manuscript is to overwrite these instructions with its text. Papers should be written in English. Manuscripts s Landfilling is the most common and cheapest method of waste management practice in India. Municipal Solid Waste Landfills (MSWL) became a nuisance affecting the health, hygiene, sanitation and aesthetics of the surrounding area. Aggregates occupy almost 70% of concrete, so replacing waste materials with them could be a rewarding choice. In the current work, an experimental investigation is being carried out to test the addition of MSWL as a substitution with fine aggregate for concrete production. Out of the different aged samples available at the dumpsite, the most aged sample is chosen for experimental investigations according to the basic physical properties. Concrete mixes, with 0%, 4%, 5%, 7% and 10% partial replacement of fine aggregate with MSWL are tested for mechanical properties such as compressive strength, split tensile strength, flexural strength, and non-destructive test and have proved to be a partial substitute for fine aggregate. Durability studies such as water absorption, acid attack and sulphate attack also gave better experimental proof for the sustainable reuse of this waste material. The research reveals 5% replacement is the optimum considering all the test result values. The paper leads to advanced research for the suitability of the material in the construction industry.

Effect of Iron Ore Tailings and High Magnesium Nickel Slag on Flyash - Ggbs Based Geopolymer Concrete (GPC)

Abstract: The cement industry is a major producer of carbon dioxide (CO2), a powerful greenhouse gas which contaminate the environment by emitting massive volumes of CO2. The building sector contributes both directly and indirectly to environmental degradation, natural resource depletion, and global warming. From a sustainability standpoint, it is critical that cement manufacturing be reduced. Geopolymer concrete (GPC) is a new material that does not require portland cement as a binder, instead, materials rich in Silicon (Si) and Aluminum (Al), such as Flyash (FA) and Ground granulated blast furnace slag (GGBS) are activated by alkaline liquids to produce the binder. The use of iron ore tailings (IOT) in place of traditional aggregates in concrete has been discovered to be feasible. Concrete made using IOT aggregate performed well with respect to strength and durable studies. GPC mix of 12M was prepared using FA, GGBS, aggregates, alkaline alkali activators such as Sodium hydroxide (NaOH) and Sodium silicate (Na2SiO3). A study on using iron ore tailings (IOT) in replacement of fine aggregates in percentages of 20, 30, 40 and 50 are studied in GPC. After achieving optimum strength in above mix then high magnesium nickel slag (HMNS) was replaced with varying percentages 5, 7.5, 10 and 12.5. As alkaline activators with 12M NaOH and Na2SiO3 solutions are used with a ratio of 2.5. Mechanical properties such as Compressive, Split tensile and Flexural strength are evaluated to determine the influence of IOT and HMNS replacement in GPC.

Study of thermal shock and chemical durability of a porcelain formulated from local raw materials from Burkina Faso

This work evaluates the resistance to chemical attack and thermal shock of porcelain formulated from local raw materials from Burkina Faso for their validation in real use. A kaolinitic clay, a pegmatite and sand were used for the formulation of porcelain tiles. Some samples were shaped by casting into porous molds and sintered at a temperature of 1240 °C. The average heating rate is 10 °C/min up to the final given temperature. These porcelains were immersed to a depth of 25 mm in test solutions and kept closed at 20 °C for 12 days. Six concentrations of test solutions were prepared to perform these tests: ammonium chloride (100 g/L); hydrochloric acid (3% and 18% by volume); lactic acid (5% by volume); citric acid (100 g/L) and alkali KOH (30 g/L and 100 g/L). The test showed that these porcelains are resistant to chemical attacks with insignificant mass variations ranging from −0.030 to 0.053 wt%. The results of the thermal shock test show that formulated porcelains are resistant to the brutal variation of temperature. The results obtained qualify the porcelains for industrial and real use.

High-Performance Nanomaterial’s in Air Filtration and Purification

Industrialization and urbanization are amongst the major sources of air pollution. Though high-performance nanomaterials offer compelling advances for air filtration and purification. In this work, several nanomaterials were tested for their ability to remove particulates (PM2.5 and PM10) and VOCs, while evaluating the wear and tear of each material. Pressure had no effect on PM2.5 capture efficiency which was 80% using activated carbon, while carbon nanotubes were more efficient in PM10 capture despite greater pressure drop. Graphene oxide was very effective in the abatement of volatile organic compounds, which was not the case for titanium dioxide which performed as good as activated carbon in the capture of PM2.5 particles but with a pressure drop of the same magnitude. Silver nanoparticles were the most effective in a percent capture of PM10 particles at low pressure drop. Yeoman’s zinc was effective in re-absorbing volatile organic compounds from the dust. The PEI-coated and electro spun nanofibers are capable of capturing PM2.5 and PM10 particles respectively, and at relatively low-pressure reductions. Results from durability studies demonstrated that TiO2 and silver nanoparticles exhibited superior efficiency retention throughout numerous cycles, but PEI-coated nanofibers saw substantial efficiency degradation

Functionalized borosilicate-silica-epoxy nanocomposite superhydrophobic coating for corrosion inhibition under harsh environment

Current work proposes a facile scheme for fabrication of robust superhydrophobic borosilicate-silica-epoxy nanocomposite coatings on steel substrate with hierarchical structures, capable of inhibiting corrosion under harsh environment. The scheme amalgamates the advantageous properties of three ingredients: acid resistant property of borosilicate glass, superhydrophobic features of functionalized silica nanoparticles and durability of epoxy resin. The various steps of synthesis include 1. ball milling of borosilicate glass to micron and submicron size (~500 nm to 1.5 μm) 2. grafting of silica nanoparticles (~20 nm, through stober method) on the borosilicate particles to form rough hierarchical structure and 3. preparation of stable dispersion of the nanoparticles in epoxy-based resin followed by coating through immersion technique. Efficacy of the scheme was established through morphological, durability and electrochemical impedance studies. The surface morphology revealed hierarchical structures of functionalized silica nanoparticles (size range 20–100 nm) grafted on micro-sized borosilicate particles, which sustained water droplets with contact angle as high as 164.5° ± 2°. Sandpaper abrasion test proved excellent durability retaining hydrophobicity up to 250 abrasion cycles. The prepared surface maintained notable interface stability under aggressive environment: 3 and 10 days under pH 1 and 13 respectively. The electrochemical study in 3.5 wt% NaCl aqueous solution showed significant decrease in corrosion current density of coated surface (0.3585 μA/cm2) compared to uncoated surface (43.918 μA/cm2) suggesting excellent corrosion resistance. The results highlight scope of using this robust coating for abrasive and harsh environment.

Performance and durability studies of a catalyst-coated membrane containing a low-Ir-content Sr(Ti,Ir)O3 anode for use in proton exchange membrane water electrolysis

Proton exchange membrane water electrolysis (PEMWE) is expected to be used in the large-scale green hydrogen production. Reducing the Ir content of the anode catalyst is desirable, as the availability of Ir is limited, thus increasing the cost of PEMWE. To reduce the Ir content, a perovskite-type Sr(Ti,Ir)O3 is investigated. Characterization and activity studies in acid suggest that the composition realizing both high catalytic activity and low Ir concentration is SrTi0.67Ir0.33O3. Prototype catalyst-coated membranes (CCMs) containing SrTi0.67Ir0.33O3 anodes are prepared. Regardless of the small Ir loading of 0.17 mgIr cm−2, high efficiencies of 86.4 % and 69.8 % are respectively observed at 1 and 2 A cm−2, and 60 °C. Long durability of 2660 h is demonstrated at 1 A cm−2 and 60 °C. The post analyses of the CCMs suggest that collapse of the perovskite structure and dissolution of the constituent elements of SrTi0.67Ir0.33O3 are factors causing degradation.

Nondestructive evaluation of mechanical heart valve disc thickness degradation due to accelerated durability test using THz-TDS measurements

ABSTRACT Quality assurance and control during the mechanical heart valve components’ production process is paramount to mitigate most of the valve-related complications arising from valve replacement. Nondestructive evaluation of heart valve implants with complex profiles during production is challenging due to the biocompatibility requirements and clean room assembly conditions. This study first tested the UHMWPE disc of TTK Chitra mechanical heart valve models TC1 and TC2 using Terahertz imaging in reflection mode. The UHMWPE discs were raster scanned in X-Y directions to obtain a Terahertz-C scan to locate the macro defects due to wear out, and to distinguish between the true positive and true negative samples. The results were verified with digital microscope studies. Second, this study investigates a unique relationship between Terahertz imaging in reflection mode and heart valve disc degradation due to accelerated durability study. Third, the variation of disc surface roughness due to accelerated durability test was studied by Gaussian curve fitting analysis of fast Fourier transform of the Terahertz reflections. Finally, a comparison between the TC1 and TC2 heart valve model’s wear-out foot print was carried out using Terahertz C-scan. Our results imply that Terahertz time-domain spectroscopy has promising applications in NDE measurements of biocompatible implants.

Calcium copper titanate incorporated polydimethylsiloxane flexible composite film-based triboelectric nanogenerator for energy harvesting and self-powered sensing applications

Triboelectric energy harvesters offer an efficient way to convert mechanical energy harvested by everyday human body actions into electrical energy. Triboelectric nanogenerators (TENGs) are an attractive solution for power supply concerns in the development of portable electronic gadgets and self-powered sensor applications. Herein, a dielectric calcium copper titanate (CaCu3Ti4O12 (CCTO)) ceramic material was synthesized by a solid-state reaction process. The synthesized particles were embedded in polydimethylsiloxane (PDMS) polymer to form a CCTO/PDMS flexible composite film (FCF)-based TENG, called a CCTO FCF-TENG, which is light-weight, simple, and suitable for use. The dielectric properties, surface charge density, and electrical conductivity of the FCF were greatly improved by the addition of the CCTO particles into the PDMS, resulting in excellent electrical output performance of the corresponding CCTO FCF-TENG. The CCTO FCF-TENG device was constructed with the CCTO/PDMS FCF, which functioned vertically against a cellulose paper to optimize a high and stable electrical output. Furthermore, the filler concentration and film thickness optimization was studied more to achieve the highest output power of the CCTO FCF-TENG. The optimized CCTO FCF-TENG exhibited the highest electrical output voltage, current, charge density, and power density of ∼250 V, ∼6.5 μA, ∼70 μC/m2, and ∼3.15 W/m2, respectively. The mechanical stability and durability of the CCTO FCF-TENG were systematically analyzed. The practical and real-time applications of the packed CCTO FCF-TENG were systematically investigated under various harsh environmental conditions. Finally, the packed CCTO FCF-TENG successfully powered several low-power portable electronics and was also used as a self-powered sensor to sense biomechanical actions in everyday human body activities.

Enhancing concrete performance through iron slag substitution: analysis of mechanical, durability and microstructural studies

Enhancing concrete performance through iron slag substitution: analysis of mechanical, durability and microstructural studies

Exhumation of HDPE geomembranes exposed to the weather for 10 years in a gold mining tailing

The durability study of a high-density polyethylene (HDPE) geomembrane that has been acting as a fluid barrier for 10 years in a gold mining dam/reservoir in Brazil was evaluated. The system stores waste considered hazardous, according to Brazilian legislation, with an average pH of 8 and presence of a cyanide solution. Samples exhumed after 10 years of service were exposed to the following three conditions: 1- only the weather; 2- contact with waste and exposure to the weather; 3- with field seams in contact with the tailings and exposure to the weather. Tensile strength, deformation under traction, tear resistance, puncture resistance and stresscracking tests were carried out. With the use of statistical tools, the results obtained were compared with the GM13 standard. Through the results analysed, it was not possible to observe significant losses in the geomembrane's resistances or a significant increase in its tensile deformation. It was observed the geomembrane did not present significant alteration in 10 years of service, with stress crack exception. The geomembrane may be able to continue to perform the function for which it was designed. It is necessary to carry out additional tests and monitor the system to understand whether or not its low performance in stress crack test is affecting the flow barrier function.

Enhanced antimicrobial performance of textiles coated with TiO2 nanoparticles

Modifying cotton fabrics to obtain significant new properties is of relevance to creating multifunctional textiles that could address challenges across different sectors. One of the critical challenges associated with textiles is hospital-acquired infections, which could be prevented through the utilization of antimicrobial fabrics. Titanium dioxide (TiO2) nanoparticles (NPs) have been introduced in literature for their photocatalytic antibacterial applications against prevalent microorganisms, such as Escherichia coli and Staphylococcus aureus. A newly developed coating process was utilized that includes chemical modification and nanocoating of cotton fabrics to achieve safe to use products that demonstrate durable and highly effective antibacterial properties. Thorough characterization was conducted to analyze the properties of the utilized materials and investigate the quality of the NPs coating on the cotton fabrics. Bacterial cultures and colony counts were performed using standard microbiological techniques. Bacterial studies revealed that the TiO2 NPs coated textile exhibited a significant antibacterial property with 99.99% bacteria growth reduction for S. aureus and E coli, in comparison to the control cotton fabrics. Coating durability analysis was also conducted by washing the coated fabrics using a standard protocol and repeating the qualitative and antibacterial characterization. The durability study revealed the outstanding performance of the coating technology to withstand at least 40x intensive washing cycles with >98% bacteria growth reduction for S. aureus and E coli. These results demonstrate the effectiveness and commercial suitability of the presented process to produce cotton textiles with outstanding antimicrobial properties that can reduce hospital-obtained infections.