Low Water Absorption Rate Research Articles

A new green rigid polyurethane foam based on modified palm oil: Preliminary study of their potential for marine buoy applications

AbstractThis study demonstrates a new green rigid polyurethane (PU) based on modified palm oil (MPO) for marine buoy applications. The bio‐polyol based on palm oil was synthesized using hydrogen peroxide and formic acid. The foam formation was by kinetic foaming reaction. The MPO‐based PU foams made with increased water content had closed cells that grew larger with water content to provide a low‐density foam. The resistance to flammability of PU foam was improved by adding triphenyl phosphate (TPP). The PU foam with increased TPP content had enlarged cells, increased water absorption and decreased compressive strength. In addition, carbon black (CB)‐containing foam had uniform, large foam cells, comparatively high density, higher compressive strength, and low water absorption. Moreover, a high CB content gave shorter extinguishing time for PU foam. The PU foams were investigated for buoyancy and compared with a commercial PU foam buoy. The commercial buoy had lower density, providing better‐floating performance than PU foam. Interestingly, CB_8 had an elevated density, but low water absorption rate, similar to the commercial buoy PU foam. The investigations showed that the PU foam from MPO is eco‐friendly, and the buoyancy performance of that foam is improved on adding TPP or CB.

Honeycombed pomegranate-like sludge ceramsite particles: Preparation with fly ash floating beads as the pore-forming template and performance optimization

Ceramsite used in construction and building are typically limited by high water absorption rates, the contradiction between lightweight and high strength, and severe performance fluctuations. This can be attributed to the fact that ceramsites are currently prepared by high-temperature sintering expansion, wherein viscosity and surface tension of the liquid phases shall perfectly match with the gas generation rate. On the other hand, sand washing sludge and fly ash are common solid wastes in construction and building and their environmentally friendly disposal are of great significance. In this study, honeycombed pomegranate-like sludge ceramsites with low density (packing density = 733.2–968.3 kg/m3), high strength (cylinder compressive strength = 11.2–18.8 MPa), and low water absorption rate (one-hour water absorption rate = 1.2–2.8 %) were prepared with sand washing sludge and fly ash floating beads as the raw material and the pore-forming template, respectively. Also, the effects of particle size and content of fly ash floating beads on the structure and performance of the as-prepared ceramsite were investigated. The results indicated that the pore structure of the as-prepared ceramsite was directly dependent on size and content of the fly ash floating beads, suggesting that the performance of the as-prepared ceramsite can be customized by tuning size and content of the beads. Additionally, lightweight aggregate concrete prepared by using the as-prepared ceramsites exhibited improved 7-day and 28-day compressive strengths and reduced thermal conductivity compared with concrete prepared by using commercially available ceramsites. Overall, this study presents the preparation of ceramsite particles with both high strength and low density by using fly ash and sand washing sludge, both of which are abundant solid wastes in constructions, thus contributing to solid waste recycling in construction.

Heritage clay brick characterization and assessment with compatible contemporary bricks for retrofitting of heritage monuments

Various mughal architecture clay brick masonry monuments were built in the Punjab state of northern India from the late 14th to late 19th centuries. Nanakshahi monuments (era of 1st Sikh Guru-Guru Nanak Dev Ji) are gigantic clay brick masonry structures constructed of lime and lime surkhi mortar (a powdered form of red burnt clay brick). Currently, this study is focused on identifying a suitable material for repairing and strengthening heritage clay brick monuments. Using the mineralogical composition of heritage Nanakshahi clay bricks (NSCB), the study compares them with contemporary clay bricks (CCB) from the same region, and then compares them to newly prepared clay bricks (NPCB), which have similar composition and dimensions to NSCB. The X-ray fluorescence confirms that the NSCB samples of southeast Punjab have an elemental composition consisting of filler SiO2 and binding elements like Al2O3, Fe2O3, CaO, K2O and MgO. The average density of ancient NSCB and CCB has been found to be similar; the ancient NSCB has a lower water absorption rate and porosity in contrast to the present-day clay bricks. The Initial rate of absorption of an ancient NSCB is quite higher. In comparison to the heritage NSCB, the CCB's compressive strength value is lower and uniaxial compression strength of newly prepared clay bricks (NPCB) of similar mineralogical composition and dimensions is comparable to that of the heritage NSCB from Punjab districts. The significance of the study is to suggest a compatible material for strengthening of heritage clay brick monuments of northern India.

An eco-friendly strategy of cell wall stapling: In situ crosslinking of acrylic acid emulsion impregnated in thermally treated poplar wood

Traditional wood modification methods often result in the release of harmful substances and energy wastage. This study proposes an efficient and environmentally friendly modification strategy for fast-growing poplar wood. The approach involves polymerizing organic linear molecules within the cell wall to form stitches, thereby enhancing the dimensional stability and mechanical properties of wood and increasing its ability to withstand various environments. Poplar wood specimens were treated via a method that combines heat treatment with acrylic emulsion impregnation. The research findings indicated an improvement in the mechanical properties of poplar wood following the combined treatment. Moreover, poplar wood subjected to this treatment approach exhibited a 35.24 % lower water absorption rate after a 7-day water immersion test, and tangential and radial swelling rates of the wood were reduced by 29.66 % and 45.68 %, respectively. Scanning electron microscopy revealed excellent penetration of acrylic emulsion into wood cells; the emulsion infiltrated the wood and adhered to the cell walls, forming a crosslinked network structure. Analysis of the modification mechanism through X-ray diffraction, Fourier-transform infrared spectroscopy, and X-ray photoelectron spectroscopy showed that the successful infusion of acrylic emulsion compensated for the lower mechanical properties of thermally treated wood, thus improving the utilization value of poplar. The acrylic emulsion is an environmentally friendly and harmless modifier, making the modified wood suitable for various applications, including indoor furniture, logistics, and outdoor facilities. This modification strategy enables efficient resource utilization and provides valuable insights for the sustainable development of the timber industry.

Production of high-strength eco-conscious ceramics exclusively from municipal solid waste

This research investigated the application of municipal solid waste incineration fly ash (MSWIFA), municipal solid waste incineration bottom ash (MSWIBA), and construction waste residue (CWR) as raw materials for the comprehensive conversion into municipal solid waste ceramics employing the SiO2-Al2O3-CaO-MgO (8 wt%) phase diagram. This study aimed to evaluate the influence of the addition of MSWIFA and sintering temperature on important ceramics properties, including linear shrinkage, water absorption, sintering range, and flexural strength. Additionally, relationships were established among these physical parameters using Pearson's correlation coefficient. The thermal behavior of the mixture was analyzed through automatic slag melting point tester and TG-DSC techniques. Furthermore, characterization of the crystalline phase transition and microstructure of sintered samples was performed by XRD, Factsage, and SEM. The results showed that both the addition of MSWIFA and the sintering temperature significantly influenced the crystal phase composition of the sintered ceramics. Moreover, the addition of MSWIFA and the sintering temperature had a significant influence on the pore structure of the ceramics. These ceramics exhibited exceptional properties, such as the extremely low water absorption rate of 0.08 % and the remarkable flexural strength of 124.78 MPa. Ceramics performance indicators were far higher than the requirements of China's national standard GB/T4100-2015. The sintering range had the capability to attain 30 °C, guaranteeing the feasibility of practical manufacturing processes. Furthermore, leaching concentration tests conducted on additive-free ceramic samples reveal a low risk of heavy metal contamination, as the heavy metals were effectively solidified within the crystalline and amorphous phases of the ceramics. The comprehensive utilization of MSWIFA, MSWIBA, and CWR for the production of fully solid waste ceramics not only yields cost reduction benefits but also promotes efficient utilization, presenting a feasible and highly promising approach to sustainable waste management.

Compósito à base de polipropileno reciclado para utilização em instalações agrícolas

ABSTRACT This study aims to develop an eco-friendly, recyclable, and cost-effective composite material for use in storage sheds and machine workshops. The new composite consists of stone dust and gravel bricks bonded by recycled polypropylene through heat treatment. The main focus of this study is to determine the effects of varying polymer proportions on the resistance and permeability properties of the studied composite, intending to achieve optimal properties, i.e., high resistance and low permeability. To do this, the 2² factorial arrangement was employed, comprising four treatments along with three central points, each replicated three times. The data was statistically analyzed at a 95% confidence level from an adapted methodology. This involved tests of compression strength, 3-point bending strength, Los Angeles abrasion, and water absorption by immersion, in which three percentages of polymer content (PC) - 15, 25, and 35% - and aggregates (fine sand, medium sand, and coarse sand - FS, MS, and CS) were used to prepare the composite. The developed composite was deemed suitable for use in storage warehouses and machine workshops, as it presented physical and mechanical appropriate characteristics, i.e., a low water absorption rate and high resistance to compression and abrasion, in addition to being an environmentally friendly composite.

Bridging gap between agro-industrial waste, biodiversity and mycelium-based biocomposites: Understanding their properties by multiscale methodology

A multiscale methodology approach was employed integrating microscopic analysis of the biomasses present in the biocomposite (lignocellulosic and fungal) to understand their macroscopic response in terms of physical and mechanical properties. Colombian native strain Ganoderma gibbosum, used for the first time in the production of biocomposites was cultivated on peach palm fruit peel flour and sugar cane bagasse wet dust, individually and as a mixture. During the solid-state fermentation were monitoring the change that occurred in substrate composition such as glucan, arabinoxylan, and lignin through biomass compositional analysis using structural carbohydrates and lignin. Moreover, fungal biomass formation was monitored via scanning electron microscopy. The resulting biocomposites underwent characterization through flexural and water absorption tests. Our findings indicated that G. gibbosum primarily degraded the polysaccharides in each of the evaluated media. However, lignin degradation to 15.06 g/g was only observed in the mixture biocomposite of peach palm fruit peel fluor and sugarcane bagasse wet dust in a ratio of 1꞉1, accompanied by a reduction in glucan and arabinoxylan weights to 26.1 and 7.72 g/g, respectively. This polymer degradation, combined with a protein-rich source in the mixture biocomposite of peach palm fruit peel fluor and sugarcane bagasse wet dust in a ratio of 1꞉1, facilitated the production of a fungal skin (biological matrix) with a high hyphal density of 65 %, contributing to Young's modulus of 3.83 MPa, elongation without failure, and low water absorption rate in this biocomposite (55 %). The lignocellulosic biomass in the culture media acted as a filler for mechanical interlocking with the matrix and provided attachment points for water absorption. Thus, our study establishes a connection between the microscopic scale and the macroscopic behavior of this biocomposite, assessing structural carbohydrates and lignin analysis during solid-state fermentation (SSF), laying the groundwork for a more customized design of mycelium-based biocomposites. Finally, this study demonstrates the possibility of tailoring nutrient composition by designing their culture media to obtain physical-mechanical properties according to the application requirement.

Ultra-low dielectric loss and high thermal conductivity of PTFE composites improved by schistose and globular alumina

Polytetrafluoroethylene (PTFE) based microwave dielectric composite has been widely used because of its adjustable dielectric constant and low dielectric loss, but its low thermal conductivity can not meet the heat dissipation requirements of high-power microwave devices. Therefore, it is of great significance to develop microwave dielectric composites with high thermal conductivity and low loss. In order to obtain microwave composite materials with high thermal conductivity and low losses, schistose Al2O3/PTFE (S-A/PTFE) composites and globular Al2O3/PTFE (G-A/PTFE) composites were successfully prepared. It is compared whether S-A can combine with PTFE more fully than G-A, which can promote the dielectric properties and thermal conductivity of Al2O3/PTFE composites. Surprisingly, the S-A/PTFE composites demonstrate higher thermal conductivity, lower thermal expansion and hygroscopic properties. The S-A/PTFE composites can deliver a high thermal conductivity of 0.986 W/m K. Composite substrates with 53 wt% S-A filler exhibits excellent performance, which specifically show credible dielectric constant (εr = 4.01) and admissible dielectric loss (tanδ = 0.0014 at 10 GHz). Furthermore, the composite substrate shows a similar thermal expansion coefficient to copper, and lower water absorption rate (0.05 %). The relationship between dielectric constant of composite and filler was predicted by different theoretical modeling methods.

Influence of Solid Waste Material Content on the Properties of Steel Slag-Waste Clay Brick Ceramic Bricks

Steel slag and waste clay brick are two common solid wastes in industrial production, and their complex chemical compositions pose challenges to the production of traditional alumina silicate ceramics. To investigate the influence of steel slag and waste clay brick on the performance of CaO–SiO2–MgO ceramic materials, this study examined their effects on the mechanical properties, crystal composition, and microstructure of the ceramics through single-factor experiments. The results demonstrate that when keeping the dosage of waste clay brick and talcum powder constant, a 43% dosage of steel slag yields optimal performance for the ceramic materials with a modulus of rupture of 73.01 MPa and a water absorption rate as low as 0.037%. Similarly, when maintaining a constant dosage of steel slag and talcum powder, a 41% dosage of waste clay brick leads to superior performance of the ceramic materials, with a modulus of rupture reaching 82.17 MPa and a water absorption rate only at 0.071%. Furthermore, when keeping the dosage of steel slag and waste clay brick constant, employing a talcum powder dosage of 24% results in excellent performance for the ceramic materials with a modulus of rupture measuring 73.01 MPa while maintaining an extremely low water absorption rate at only 0.037%. It is noteworthy that steel slag contributes to akermanite phase formation while talcum powder and waste clay brick contribute to diopside phase formation.

Improvement of the anti-corrosion coating properties of waterborne epoxy resin with the incorporation of fluoropolymer-modified silica nanofillers

The objective of this research was to enhance the corrosion resistance and mechanical properties of silica nanoparticles modified by a fluoropolymer (polyhexafluorobutyl acrylate, PHFBA) by incorporating them into a waterborne epoxy resin (WEP) coating system. Initially, polyhexafluorobutyl acrylate (PHFBA)-modified silica nanoparticles were synthesized using a two-step method, involving the grafting of 3-(isobutylloxy) propyl trimethoxysilane (KH570) onto SiO2 to produce SiO2@KH570, followed by a random copolymerization of SiO2@KH570 with hexafluorobutyl acrylate (HFBA) to obtain the fluoropolymer-modified SiO2 (FxSiO2). Subsequently, the chemical structure and elemental composition of SiO2, as well as the prepared SiO2@KH570 and FxSiO2 nanoparticles, were comprehensively investigated. Moreover, FxSiO2/WEP composite coatings with different amounts of fluoropolymer-modified nanofillers and x-F5SiO2/WEP composite coatings with varying amounts of F5SiO2 nanofillers were prepared and characterized. The findings revealed that the functionalized FxSiO2 exhibits superior dispersion, interface, and size effects, significantly enhancing the overall performance of WEP coatings. Notably, when 0.1 wt% F5SiO2 nanofiller was incorporated, the resulting 0.1-F5SiO2/WEP composite coating demonstrated a considerable impedance modulus (1.171 × 108 Ω∙cm2), relatively low water absorption rate (about 11 % after 20 d of immersion in water), and robust mechanical properties: a tensile strength of 6.07 MPa and an elongation at break of 37.36 %. Moreover, the hardness and adhesion of the composite coating remain unaltered. Furthermore, after 20 days of salt spray testing, the electrochemical impedance still reached 8.765 × 106 Ω∙cm2, indicating a favorable long-term anti-corrosion capability. Consequently, the integration of fluoropolymer-modified nanoparticles in water-based epoxy resins holds great potential.

Waste Glass in Road Construction: A Review

Several attempts have been made on the use of alternative material for constructionpurpose. This is to limit the exploitation of the natural resources and the need to engage onrenewable resources that can function adequately in road construction with minimal carbonfootprints. The main objective of this review is to consider the outcome of the suitability of wasteglass products in the construction of roads based on the existing studies. From the relevant literatureconsulted, it was discovered that waste glass powder has the capacity to improve the compressiveand tensile strength of asphalt mix. Also, it has lower water absorption rate, thereby making itimpossible for the penetration of the chloride ions which usually accelerate road degradation. Inaddition to this, it improves the workability of the concrete used for the pavement construction,hence, it is more advantageous when compared with sand. The findings from this study will help theconstruction industry on the methods of waste glass recycling and its adoption into roadconstruction.

Sliding wear behaviour of micro-sized Kota stone dust reinforced epoxy composites using Taguchi method and Grey Wolf optimisation algorithm

Kota stone dust (KSD) is an unwanted material engendered throughout the process of manufacturing Kota stone. The present work comprises the appropriate consumption of KSD for evolving a composite system with epoxy as the base matrix material. The samples are developed by the hand lay-up technique. The micrographs clearly show that KSD is uniformly distributed within the epoxy matrix and establishes good adhesion with it. With the inclusion of filler, density unwillingly increases by 21.86%, but voids generated are limited to only 4.98% for a maximum filler content of 40 wt. %. A very low water absorption rate of 0.81% for maximum filler loading is observed. The compressive strength and micro-hardness increased by 31.8% and 26.25% respectively. Tensile strength, as well as flexural strength, improves for low filler loading of 20 wt. % and decreases thereafter. The sliding wear tests of the fabricated composites are studied in this research employing fairly advanced nature-inspired Grey wolf optimisation (GWO). The wear tests are based on a real-world issue that is framed in Taguchi L25 OA. A simple linear regression equation demonstrates adequate agreement between predicted and experimental values. The inclusion of KSD decreases the wear rate. Further, it is found that the KSD loading is the utmost significant factor, whereas normal load is the least significant factor that administrates the sliding wear rate of the composite system. Using the grey wolf optimiser, the optimal settings are 2500 m sliding distance, 40 wt.% KSD content, 52 cm/s sliding velocity, and 10 N normal load. The validation test results suggest that GWO is superior to the classical Taguchi approach. The wear loss mechanism is examined under the scanning electron microscope.

Implantable Neural Electrodes Fabrication Based on Perfluoroalkoxyalkane Film.

In this paper, the fabrication of perfluoro-alkoxy alkane (PFA) film-based planar neural electrodes was proposed. The fabrication of PFA-based electrodes started with cleaning of PFA film. The argon plasma pretreatment was performed on the PFA film surface and attached to a dummy silicon wafer. Metal layers were deposited and patterned using the standard Micro Electro Mechanical Systems (MEMS) process. Electrode-sites and pads were opened using reactive ion etching (RIE). Lastly, the electrode patterned PFA substrate film was thermally laminated with the other bare PFA film. Electrical-physical evaluation tests were conducted along with in vitro tests, ex vivo tests and soak tests to evaluate the electrode performance and biocompatibility. The electrical and physical performance of PFA-based electrodes had better performances compared to other biocompatible polymer-based electrodes. Also, the biocompatibility and longevity were verified by cytotoxicity test, elution test, and accelerated life test. The PFA film-based planar neural electrode fabrication was established and evaluated. The PFA based electrodes showed excellent benefits such as long-term reliability, low water absorption rate, and flexibility using the neural electrode. For implantable neural electrodes, hermetic sealing is required for in vivo durability. PFA fulfilled a low water absorption rate with relatively low Young's modulus to increase the longevity and biocompatibility of the devices.

Ataque de sulfato em geopolímero: efeito da proporção do ligante e aditivo incorporador de ar

Abstract This research aimed to evaluate the resistance to sodium and magnesium sulfates of geopolymeric mortars, prepared with different proportions of alkaline activators of silicate and sodium hydroxide (Ma), Na2O content in relation to metakaolin (MK) and silica modulus (Ms). Additionally, an air-entraining additive was also used in an attempt to mitigate the expansive effects of sulfate attack for 20 weeks. The sulfate resistance properties were evaluated by the change in longitudinal length, mass variation, compressive strength, flexural tensile strength, and microstructure. SEM/EDS analyses suggest the formation of caminite and a change in the structure of the aluminosilicate gel to M-A-S-(H) in mortars exposed to MgSO4, while thenardite was indicated as a harmful product in mortars subjected to Na2SO4. The experimental results also showed that the greater amount of Na2SiO3 in the geopolymer formulation contributes to a denser structure and lower water absorption rate, but resulted in greater physical deterioration and expansion after immersion in sodium magnesium sulfate. The air-entraining additive did not minimize the tensions generated by the sulfate attack. In mortars synthesized with Na2O/MK = 15% and Ms = 1.5 (GEO-15-1.5) and Na2O/MK = 22% and Ms = 1.0 and 1.5 (GEO-22-1.0 and GEO-22-1.5), the compressive strengths were similar to standard samples when immersed in MgSO4, while in the Na2SO4 solution the increase in strength was attributed to the temporary refinement of the pores by sulfate crystals.

Study of the Mechanical Properties of the Fly Ash Composite Bricks

Fly ash brick is an eco-friendly construction material comprised of fly ash, bottom ash, cement and rice husk. Fly ash, a by-product of coal-fired power plants is utilized in place of typical clay or lime in the manufacturing process. One of the key benefits of fly ash brick is its long-term viability. Utilizing fly ash in the manufacturing process lowers waste generated by power stations and the requirement for virgin resources. Fly ash brick also has a reduced carbon impact than typical clay bricks. In terms of performance, fly ash brick offers various benefits. The bricks are more robust and resistant to weathering because they have a higher compressive strength and lower water absorption rate than ordinary clay bricks. They are also well insulated and have a low thermal conductivity. Fly ash brick is also cost-effective since it takes less energy to produce and is less expensive than typical clay bricks. Fly ash bricks are better for the environment since they have a reduced carbon footprint than ordinary clay bricks. They also offer numerous advantages, such as sturdy, long-lasting, and weather-resistant. They also have strong insulation characteristics, which means they can keep a structure cool in the summer and warm in the winter. Fly ash bricks are also a suitable alternative for construction since they are less expensive than regular clay bricks. They also take less energy to manufacture, making them more cost-effective. In this paper, we study the comparison of conventional break and fly ash brick on various dimensions like compressive strength and water absorption test. In this study, the Taguchi technique of parameter design is used to describe the findings of an experimental investigation into the mix proportions of fly ash bricks. With four factors and three levels per factor, the experiments were created using a L9 orthogonal array

The influence of carbon imperfections on the physicochemical characteristics of coal gangue aggregates

In order to promote the development of coal gangue aggregate concrete and the resource utilization of coal gangue solid waste, the coal gangue samples were crushed into aggregates, and then the macroscopic characteristics and microscopic structures of the aggregates were characterized through methods such as calcination, sulfuric acid solution dry-wet cycle, XRD, TG-DTG, and SEM-EDS, based on the Chinese national aggregate standard, the key influencing factors of the physicochemical properties of coal gangue aggregates were analyzed. The results show that coal gangue with lower loss on ignition and carbon content has smaller crushing value, lower water absorption rate, and stronger soundness. The carbon content and carbon distribution significantly affect the macroscopic physicochemical properties of coal gangue aggregates. Carbon, as a defect, is uniformly distributed in coal gangue, which increases the crushing value of coal gangue aggregates and greatly reduces their soundness, leading to the “second-order adverse effect” and “opening window effect”, which are detrimental to the durability of coal gangue aggregate concrete. The composition and physicochemical properties of a large number of coal gangue samples were determined, and the correlation between composition overlay effects on physicochemical properties were analyzed using a “three-dimensional surface”. This analysis confirms the adverse effects of carbon defects on the physicochemical properties of coal gangue aggregates. Carbon content can be used as the primary control index for coal gangue in resource utilization.

Utilization of Crumbs from Discarded Rubber Tyres as Coarse Aggregate in Concrete: A Review

This research work successfully reviewed twenty-five papers on waste rubber tyres and their related areas. The chemical and physical properties of concrete constituents such as cement, water, sand and rubber crumbs were reviewed together with their mix ratios. The use of Tyre Rubber Crumbs (TRC) to replace coarse aggregates makes concrete construction work cheaper and its low water absorption rate improves the concrete mix properties such as compressive strength and workability. Hence, in road pavement construction, the use of TRC in asphalt modification is the best and smartest innovation for sustainable development and waste material reuse. This research showed that waste TRC are very essential in the replacement of some aggregates in the construction industries resulting in very high-quality construction and as well minimize construction costs.

Fabrication and properties of high-thermal-storage RTO ceramics using bauxite tailings and red mud

Nowadays, it is critical to find materials and methods that can help reduce the human impact on the environment. Regenerative thermal oxidizers (RTOs) have a wide range of applications owing to their effective energy saving. Among the different RTOs, thermal-storage RTO ceramics have basic heat storage and release capability. The main objective of this work is to study the preparation of thermal-storage RTO ceramics for the treatment of exhaust gas using bauxite tailings and Bayer red mud from Jiaozuo City (Henan Province) with different mass fractions of magnetite as substitutes for the traditional raw materials (quartz and clay). The effect of the magnetite addition on the performance of the thermal-storage RTO ceramics prepared from the bauxite tailings and red mud was investigated. The raw materials were pressed into cylinder shape and then sintered at 950 °C, 1000 °C, 1050 °C, and 1100 °C. The developed materials were analyzed and characterized via X-ray diffraction and scanning electron microscopy, and specific heat capacity tests (differential scanning calorimetry using the sapphire method) were conducted on the thermal-storage RTO ceramics prepared at the optimal sintering temperature (1050 °C). The ceramics exhibit the best overall performance for magnetite content of 25% and sintering temperature of 1050 °C, with compressive strength of 134.96 MPa, volume density of 3.00 g/cm3, and linear shrinkage of 14.68%. The product also has a remarkably low water absorption rate and apparent porosity, water absorption of 0.02%, apparent porosity of 0.06%. Furthermore, the specific heat capacity is sufficiently high to meet the requirements of high-thermal-storage RTO ceramics. This study provides a new, low-cost solution for the preparation of high-thermal-storage RTO ceramics, which is helpful for reducing the exploitation of natural mineral resources.

Experimental studies on durability and deflection behavior of concrete in metakaolin cement concrete

The most frequently used components in conventional concrete are cement, sand, coarse aggregate, and water. Cement production and hydration produce a lot of heat and release the greenhouse gas CO2, which contributes to climate change and global warming. By employing industrial wastes like GGBS, metakaolin, and copper slag, concrete may be manufactured largely without cement and sand. In this investigation, seven M30 grade concrete mixes—designated M1, M2, M3, M4, M5, M6, and M7—as well as a control mix are produced. The super plasticizer content in cement is 0.75 percent by weight. The maximum and minimum cement replacement rates for GGBS and Metakaolin are 5% and 10%, respectively. 20%, 40%, and 60% of copper slag are replacement values. Acid attack, water absorption, sorptivity, and porosity are a few examples of properties that contribute to workability and durability. The flexural behaviour of an RCC beam is examined. In terms of RCC beam behaviour, the mixture of MC4 with 5% GGBS, 5% MK, and 40% copper slag offers the highest flexural toughness rating. Due to copper slag's low water absorption rate, concrete can progressively increase in strength by up to 40%. Of the seven, the MC5 mixture is the toughest. Because of the high surface area and pozzolanic activity of GGBS and metakaolin, mix MC5 has the lowest water absorption, sorptivity, and porosity values of all the mixes. The most acid resistance is found in the MC2 mixture, which contains 20% copper slag, 5% GGBS, and 5% metakaolin. This is true for both hydrochloric acid and sulfuric acid.

Enhancement of natural fiber-reinforced plastics by polyester and seaweed waste fibers

A bio-based composite material made from wastes from Posidonia oceanica (PO) and sugar cane polyester (SCPES) has been developed in the current work. DSC and TGA have been used to investigate the thermal deterioration of composites, and the results demonstrate an improvement. Using dynamic mechanical analysis (DMA) data, it has been found that the storage modulus (G) increases significantly as the Posidonia oceanica concentration rises. There has been a 60 % increase in stiffness in 40 % composites compared to unfilled materials in tensile test results. Flexural modulus of polyester, when unloaded is more than twice that of polyester, when fully loaded. In addition, Shore D hardness as well as Charpy impact test findings reveals that HDPE's intrinsic high impact energy absorption is intact in HDPE-PO composites, confirming this improvement in mechanical properties. As a result of the low water absorption rate (less than 8 %) and the long immersion time, these composites are assured to preserve their dimensional stability.