Optimal Proportion Research Articles

Mix proportion and microscopic characterization of coal-based solid waste backfill material based on response surface methodology and multi-objective decision-making

The mix proportion of multi-source coal-based solid waste (CSW) for underground backfilling affects transportation and support performance of backfill materials, and even the backfilling cost. In this study, the optimal mix proportion of desulfurization gypsum (DG), furnace bottom slag (FBS) and gasification fine slag (GFS) is determined by the Response Surface Methodology–Box Behnken Design (RSM-BBD). Then the fluidity, bleeding rate, 3-day strength, 7-day strength and preparation cost are evaluation indicators, the optimal mix proportion of backfill materials is determined by the multi-objective decision-making method (MDM). Finally, the microstructure of the backfill material with optimal mix proportion was studied by TGA, MIP, SEM–EDS and XRD. The results show that the mix proportion of CSW with the optimal comprehensive index is coal gangue (CG): coal fly ash (CFA): DG: FBS: GFS = 1:1.5:0.2:0.1:0.1, the mass concentration is 78%, and ordinary Portland cement (OPC)/CSW = 7.5%. The weight loss phenomenon of the backfill material with the optimal mix proportion occurs continuously during the heating process, mainly due to the evaporation of crystal water, structural water and hydroxyl water. There are dense narrow-necked pores in the backfill material, and the pore connectivity is poor. There is no hydration reaction occurs between CSW particles, and the strength increase of the backfill material mainly depends on the hydration reaction of cement. In ettringite, part of Al2O3 is replaced by SiO2, and part of CaSO4 is replaced by CaCO3. This study provides a reference for the engineering application of underground backfilling with multi-source CSW.

Optimal proportioning of iron ore in sintering process based on improved multi-objective beluga whale optimisation algorithm

Optimal proportioning of iron ore in sintering process based on improved multi-objective beluga whale optimisation algorithm

Preperation and Performance Comparision of Autoclaved Aerated Concrete by Using Ceramic and Glass Wastes Instead of Silica

This study aimed to produce autoclaved aerated concrete (AAC) by using glass and ceramic waste in 10%, 20%, 30%, 40%, and 50% proportions as a substitute material for quartzite, and samples were produced under low pressure and heat (2.3 bar and 135 ºC). The microstructural properties were investigated by employing scanning electron microscopy (SEM) analysis. Unit weight, porosity, water absorption, ultrasonic wave velocity, compressive strength, and thermal conductivity parameters were experimentally investigated and compared to a control sample produced without waste. Test results showed that waste addition leads to decreasing porosity, water absorption, and increasing unit weight. Additionally, uniaxial compressive strength, thermal conductivity, and ultrasonic wave velocity values were increased by adding waste. The test results showed that glass and ceramic waste can be used as a quartzite sand replacement in the production of AAC and the optimum replacement proportions for the waste materials was 10%.

Experimenting the influence of corncob ash on the mechanical strength of slag-based geopolymer concrete

Abstract The construction sector has been under growing public attention recently as one of the leading causes of climate change and its detrimental effects on local communities. In this regard, geopolymer concrete (GPC) has been proposed as a replacement for conventional concrete. Predicting the concrete’s strength before pouring is, therefore, quite useful. The mechanical strength of slag and corncob ash (SCA–GPC), a GPC made from slag and corncob ash, was predicted utilizing multi-expression programming (MEP). Modeling parameters’ relative importance was determined using sensitivity analysis. When estimating the compressive, flexural, and split tensile strengths of SCA–GPC with MEP, 0.95, 0.93, and 0.92 R 2-values were noted between the target and predicted results. The developed models were validated using statistical tests for error and efficiency. The sensitivity analysis revealed that within the mix proportions, the slag quantity (65%), curing age (25%), and fine aggregate (3.30%) quantity significantly influenced the mechanical strength of SCA–GPC. The MEP models result in distinct empirical equations for the strength characteristics of SCA–GPC, unlike Python-based models, which might aid industry and researchers worldwide in determining optimal mix design proportions, thus eliminating unneeded test repetitions in the laboratory.

Modern Concepts of Restructured Meat Production and Market Opportunities.

Restructured meat (RM) products are gaining importance as an essential component of the meat industry due to consumers' interest in health benefits. RM products imply the binding or holding of meat, meat by-products, and vegetable proteins together to form a meat product with meat's sensory and textural properties. RM products provide consumers with diversified preferences like the intake of low salt, low fat, antioxidants, and high dietary fiber in meat products. From the point of environmental sustainability, RM may aid in combining underutilized products and low-valued meat by adequately utilizing them instead of dumping them as waste material. RM processing technique might also help develop diversified and new hybrid meat products. It is crucial to have more knowledge on the quality issues, selection of binding agents, their optimum proportion, and finally, the ideal processing techniques. It is observed in this study that the most crucial feature of RM could be its healthy products with reduced fat content, which aligns with the preferences of health-conscious consumers who seek low-fat, low-salt, high-fiber options with minimal synthetic additives. This review briefly overviews RM and the factors affecting the quality and shelf life. Moreover, it discusses the recent studies on binding agents in processing RM products. Nonetheless, the recent advancements in processing and market scenarios have been summarized to better understand future research needs. The purpose of this review was to bring light to the ways of sustainable and economical food production.

Optimization and preparation of a compound cod liver oil film former agent: an orthogonal design.

Background: Cod liver oil has anti-inflammatory properties and could help regulate recurrent aphthous stomatitis (RAS). An orthogonal experiment was used to evaluate and improve the dosage form of compound cod liver oil, which has replaced the previously used liniment preparation based on film method. Methods: An orthogonal experiment was adopted, and the appearance and film-forming time of the film coating agents were used as indicators. The optimal ratio in the preparation process for the compound cod liver oil film agent was then optimized. A method for determination of compound cod liver oil film was established using High-Performance Liquid Chromatography (HPLC). Results: The results indicate that the blank films prepared using 55mg polyvinyl alcohol (PVA) (PVA low), 45mg of PVA (PVA medium), and 10mg glycerol had the optimal performance, which was defined as PVAa. The drug-carrying film prepared from 3mL PVAa (i.e., film-forming material with the optimal proportion), 30mg dexamethasone acetate, and 30mg metronidazole had the optimal performance. The verified sample has a complete and smooth appearance, uniform thickness and color, and no evident bubbles, which meets the requirements for a film agent defined in the Chinese Pharmacopoeia, 2020 edition. HPLC was used to determine the major components: dexamethasone acetate, metronidazole, and dyclonine hydrochloride, and the optimal separation effect was obtained. The method has advantages of good specificity, good linear results, high recovery rate, and good repeatability. Conclusion: This study proposes an optimized compound cod liver oil film former agent and preparation method. The results indicate that the compound cod liver oil film former agent had good performance, reflecting the high feasibility of this research method. The detection method of compound cod liver oil film was established by HPLC. The method was feasible, and the validity and stability of the formulation and preparation technology were guaranteed. The role of the newly developed agent in patients with RAS should be investigated further.

Optimum Design of Mixture Proportion and Microscopic Analysis of Cement-Stabilized Macadam by Rubber Powder and Fiber

Abstract Based on the orthogonal test method, the mixture proportion design of cement-stabilized macadam (CSM) modified with rubber powder and fiber is studied. With strength and dry-shrinkage as key indices, the influence of length of polyvinyl alcohol (PVA) fiber, fiber content, particle size of rubber powder, and rubber powder content on the performance of CSM is analyzed, and the optimum mixing proportion is determined. Based on this, the modification mechanism of CSM by rubber powder and fiber is further studied from a micro perspective. The results show that the 7-day unconfined compressive strength of CSM gradually increases with the increase of fiber length. With the increase of fiber content, the compressive strength shows a trend of first increasing and then decreasing. The 7-day unconfined compressive strength of CSM gradually increases with the increase of rubber powder mesh size and linearly decreases with the increase of rubber powder content. The 28-day average dry-shrinkage coefficient of CSM shows a trend of first decreasing and then increasing with the increase of fiber length and fiber content, and gradually increasing with the increase of rubber powder mesh number and rubber powder content. Considering the strength and shrinkage characteristics, the optimum mixing parameters are 40 mesh rubber powder, 0.5 % rubber powder, 18-mm fiber length, and 1.2-kg/m3 fiber content. Scanning electron microscopy results show that there is a gap between the rubber powder and the cement matrix, and the interface between the two is discontinuous, with weak bonding, resulting in a decrease in the compressive strength of CSM. PVA fiber can improve the toughness of CSM. It has good adhesion with cement matrix. It forms a three-dimensional network support structure in the CSM mixture and can restrain water loss in the cement matrix, thus greatly improving the cracking resistance of CSM.

Optimization of recycled rubber self-compacting concrete: Experimental findings and machine learning-based evaluation

This research aims to assess the rheological and mechanical characteristics of Self-compacting concrete (SCC) incorporating waste tire rubber aggregates (WRTA) as an interim substitute for coarse aggregates. However, the standard experimental modeling approach has significant obstacles when it comes to overcoming the nonlinearity and environmental susceptibility of concrete parts. Therefore, linear regression (LR) and extreme gradient boosting (XGBoost) were used as two standard single machine learning (ML) models to predict the aforementioned rubberized SCC features. In this study, conventional coarse aggregates were supplanted with WRTA at 0%, 5%, 10%, and 20% to uncover the optimal proportion of coarse aggregates substituting rubber. To find the optimum amount of WRTA to use as a substitute, the study follows the impacts of rubber on the self-compacting rubberized concrete's (SCRC) rheological and mechanical characteristics. The consequences on fresh properties were investigated by the slump flow, J-ring, and V-funnel tests, while compressive and splitting tensile strengths tests were conducted to assess mechanical properties. Increasing WRTA test outputs indicated a deterioration in workability and hardened qualities. While a 10% swapping ratio is deemed feasible for producing SCRC, optimal results were achieved by reducing environmental impacts and efficiently managing a significant volume of rubber tire waste with a 5% substitution of rubber within the coarse aggregates. The research findings indicated a noticeable decrease in fresh properties as the WRTA content increased. Notably, after 28 days, a 10% WRTA substitution led to a 34% reduction in compressive strength and a 28% decrease in splitting tensile strength, satisfying ACI standards. Furthermore, XGBoost demonstrated superior predictive performance with the highest R2 values, outperforming the LR model and affirming its efficacy in delivering more accurate predictions.

Повышение огнестойкости полимерных строительных материалов для обеспечения пожарной безопасности работников

Occupational safety is a crucial factor in the protection of employees in the service and production industries. It is specifically critical for the construction industry where fire safety measures must be taken into account. Ensuring the fire safety for employees is a complex task requiring constant attention and observance of established rules and procedures. Currently, integrated measures are implemented and certain results are achieved in the sphere of the further implementation of economic reforms in the building materials industry, including the expansion of the production of the most up-to-date materials, structures, and products, and the expansion of their range. The study provides methods to increase the fire resistance of polymer building materials; their physical & mechanical and thermodynamic properties as well as the optimal proportions of fly ash and phosphogypsum to obtain composites for such materials have been investigated. The studies of the elementary composition of industrial manmade wastes and their X-ray diffraction analysis have shown that they mainly consist of silicon dioxide that by more than 80 % consists of the amorphous phase. With the X-ray diffraction analysis, it has been determined that the introduction of fly ash fillers and phosphogypsum waste into the composition increases the thermal stability of polymer materials. The main cause is metal and silicon oxides and phosphorous compounds resistant to temperatures and with the properties of flame-retardants contained in the polymer composite as introduced additives. Based on experimental tests, the fire-resisting properties of the polymer-containing building materials modified with fire-resisting compositions consisting of binding polymer flame-retardant additives and fillers have been studied. The oxygen index increased from 18.5 to 33 %, whereas the mass loss at thermal oxidation decreased from 97.5 to 73–75.5 %, and the flammability level, under GOST 28157, was changed from PV-2 to PV-0.

Determination of Optimal Stock Portfolio Return by Single Index Model (Case Study on Banking Sector Stocks in Indonesia)

The optimal portfolio is a portfolio chosen by investors from the many options available in the collection of efficient portfolios. To get the optimal proportion, which is the maximum return and minimum risk, it is necessary to analyze the stocks to be selected in the investment model. The research objective is to determine the optimal return, risk, and proportion for each banking stock portfolio in Indonesia in the period February - July 2023. The method used is the Single Index Model. The process of determining the optimal proportion of stocks with the Single Index Model requires stock and market return data as the main basis for applying this method. This study involves the formation of an optimal portfolio of daily closing prices of 46 banking stocks. As a result of this research, there are 5 optimal stocks that meet the criteria for optimal portfolio formation with each fund proportion of 21.43% (BNII), 13.52% (BDMN), 35.02% (BBRI), 23.69% (BTPN), and 6.34% (BBCA). Expected return from optimal stocks is 0.152% and the risk that will be borne by investors is 0.0011% per day.

Nutritional, Biochemical, and Functional Properties of Pearl Millet and Moringa oleifera Leaf Powder Composite Meal Powders.

This study sought to improve pearl millet's nutritional, functional, and biochemical properties through malting and fermentation. Moringa oleifera leaf powder (MLP) was used as a fortificant. Mixture design was used to find optimal proportions for each component that yielded a high protein and or low saturated fat content. Twelve mixtures with varying ratios of fermented and malted pearl millet flour ranging between 30-65% and MLP between 5-15% were generated through I-Optimal mixture design. The mixtures were wet-cooked, freeze-dried, and analysed for protein and fat content. The data obtained were fitted to a linear mixture model, and the search for the optimum was conducted using Numerical Optimisation for maximising protein and minimising saturated fat. The linear model was suitable for explaining total protein and saturated fat variation with r2 of 0.50 and 0.51, respectively. Increasing MLP increased protein content. Two final formulations, Optimisation Solution 1 (OS1) and Optimisation Solution 2 (OS2), were generated through the optimisation process. Pearl millet's protein content increased by up to 22%, while saturated fat decreased by up to 13%; ash content increased by 75%. Polyphenol content and oxygen radical absorbance capacity increased by 80% and 25%, respectively. Final and peak viscosity were reduced by 90% and 95%, respectively.

Использование семян льна-долгунца при производстве безалкогольного пива «Светлое»

Research is presented on replacing part of the barley malt with flax seeds in the production of beer wort and its effect on physicochemical parameters. The greatest value for the duration of saccharification and filtration was obtained with the addition of 4% fiber flax seeds. The duration of saccharification increased from 5 to 15 minutes, and the duration of filtration from 75 to 180 minutes. When replacing barley malt with 1% fiber flax seeds, the acidity and mass fraction of moisture do not exceed the GOST requirements. The use of fiber flax seeds in the production of beer wort did not affect the transparency of the finished product, but a pleasant nutty smell and mild taste appeared. The production of beer wort, the optimal proportion of flax seeds when replacing barley malt is 1%. Since when it increases to 4%, the acidity and mass fraction of moisture in the wort do not meet the requirements of GOST, this may affect the quality of the finished product and its shelf life. The results obtained must be taken into account in the further development of the non-alcoholic beer recipe. Keywords: FIBER FLAX, BARLEY MALT, BEER WORTH, NON-ALCOHOLIC BEER

Allocating Benefits Due to Shared Resources Using Shapley Value and Nucleolus in Dynamic Network Data Envelopment Analysis

Shared resources are common among supply chain partners and also occur in multiple linked stages of an internal network. The sharing of these resources impacts the organization’s profits. This study is focused on the potential benefits of resource sharing on a three-stage network system and on the profit improvement allocation. Previous treatments concentrate on defining optimal proportions to allocate resources and disregard the impacts of allocations to promote cooperation and are limited to static evaluations. Data Envelopment Analysis performs the decision-making units (DMUs) efficiency measurement. Methodological advances have resulted in models that analyze their internal structure and temporal impacts on efficiency. We propose an integrated cooperative game and dynamic network DEA that considers known quantities of resources used in each stage and the time effects to optimize the system’s profit. Each DMU stage is a player, and we investigate performance before and after resource sharing. Using Shapley value and Nucleolus, it is possible to allocate the benefits obtained based on the marginal contributions of each stage, providing incentives to motivate and maintain cooperation. A numerical example is used to illustrate the method. The results confirm the identification of inefficient DMUs and that sharing resources allows for profit increase for all of them.

Study of The Influence of Storage Media on the Thermo-mechanical Behavior of Concrete and Cement Blocks

Once all construction materials have been formulated, it is necessary to find a suitable environment in which to store them before using them in the building. Generally speaking, in developing countries, materials are not preserved under the real conditions of temperature and humidity and are exposed to often severe climatic conditions. This has an impact on the behaviour of these materials. With this in mind, we conducted our study on concrete and cement bricks, the two materials most commonly used in building construction in Africa. The overall objective of our study is to analyse the effect of storage environments, particularly ambient conditions of temperature and hygrometry, on the thermal and mechanical properties of concrete and cement bricks in a dry tropical climate. To achieve this objective, we first analysed the quality of the materials used to formulate the concrete and cinder block samples. Next, we chose a formulation method that would enable us to obtain the optimum proportions of aggregates. Finally, the thermal and mechanical parameters were measured using the KD2-Pro device and a mechanical press, respectively. The concrete and cinder block samples were stored for 28 days and 10 days respectively in the open air under ambient climatic conditions (35°C on average),in a water tank (29°C on average) and in a climatic chamber (20°C and 53% relative humidity). Results ranged from 1.126 (± 0.003) to 1.289 (± 0.023) W.m-1. K-1 for thermal conductivity. Mechanical test results ranged from 3.93 (±0.45) to 4.13 (±0.27) MPa for flexural strength and 16.42 (±0.17) to 17.95 (±0.21) MPa for compressive strength. The lowest thermal conductivity was obtained in the climatic chamber, with a value of 1.126(±0.0032)W.m-1.K-1.The best compressive strength of concrete and the best flexural strength of cement blocks were obtained for samples stored in the climatic chamber. For the best mechanical and thermal behaviour of these two materials, we recommend a temperature not exceeding 20°C as the storage environment in a dry tropical climate.

Application of geopolymer in synchronous grouting for reusing of the shield muck in silty clay layer

This study employs geopolymer as a complete replacement for the cement to solidify the shield muck discharged from tunneling in the silty clay layer, thereby creating an innovative synchronous grouting material. This novel grouting material not only utilizes geopolymer as its primary cementitious component but also incorporates shield muck, promoting the efficient utilization of the shield muck. The cementitious process of the grout is initiated by the principles of geopolymerization. Through a series of laboratory tests assessing grout performance, the new grouting material was developed by further optimizing the grout proportion using the response surface method (RSM). This involves a comprehensive analysis of the impacts of various factors such as muck moisture content, foam injection ratio, ground granulated blast furnace slag (GGBS) content, and sand content, along with their interactions on the key response variables, including consistency, fluidity, 2 h bleeding rate, setting time, and 3 d unconfined compressive strength (UCS). The optimal proportion of the new grouting material is found to be 140% muck moisture, 100% GGBS, and 230% sand. Experimental results reveal that the GGBS content has the most significant effect on various properties of the grout, while the interaction between these factors has distinct effects on different grout properties. This novel synchronous grouting material was subsequently employed in the Nanjing Metro Line 6 project, and it was found that both surface settlement and segment uplift meet the specified requirements.

Mechanical properties and field test of lime-soda residue stabilized soil for subgrade

To broaden the sources of subgrade filler and the utilization of Soda Residue (SR), SR was employed to modify clay by adding a small amount of lime for further stabilization, forming a Lime-Soda-Residue-Stabilized Soil (LSRSS). A set of intensive research paths was established, from testing of laboratory mechanical property, mechanism disclosure, and field verification to operational effect. Through Unconfined Compressive Strength (UCS), California Bearing Ratio (CBR), and Resilient Modulus (MR) experiments, it was concluded that with the increase in SR content, the UCS, CBR, and MR values of LSRSS showed an increasing trend then followed by a decrease, reaching their peak values, respectively of 0.62 MPa, 65.0%, 78.83 MPa, all at 30% SR content. An optimal proportion was determined for LSRSS as 6% lime, 30% SR, and 70% clay. The UCS, CBR, and MR values of optimal proportion all increased with the increase of compaction degree, but increased first and then decreased with the increase of water content. Their maximum values did not correspond to the OWC of 23% but to 27%, called the compaction water content, which was suitable for application in the actual LSRSS subgrade. Field test results showed that the UCS, CBR, and MR values were 0.85 MPa, 86.5%, and 135.7 MPa, which all were higher than the laboratory values, and the long-term road performance was outstanding. The analysis demonstrates that the better strength and road performance of LSRSS are mainly determined by the superior gradation and the reaction of three materials. The laboratory and field test results collectively provide data evidence for excellent performance and lay a solid foundation for the wider application of the LSRSS subgrade.

Preparation and performance analysis of polyamide-based rapid repair material for asphalt pavement shallow groove

In order to effectively remedy shallow grooves on asphalt pavements, this study presents an innovative solution, termed Polyamide-based Asphalt Pavement Shallow Groove Rapid Repair Material (PA-SGRRM). This material employs polyamide 6 (PA6) as the matrix resin, in conjunction with polypropylene (PP), ethylene-vinyl acetate copolymer (EVA), and maleic anhydride-grafted polyethylene-octene copolymer (POE-g-MAH). It is manufactured through an extrusion granulation process. At the outset, a molecular dynamics approach was employed to assess the compatibility of the primary constituents and the adhesion between the matrix resin and asphalt, confirming the rationale behind the material selection. Subsequently, the orthogonal experimental design method was utilized to investigate the influence of design parameters (POE-g-MAH content, PP content, and EVA content) on the flexural strength, tensile strength, low-temperature toughness, and melt flow rate of PA-SGRRM. Following this, we prepared samples with the optimal proportions of EVA and POE-g-MAH and conducted a separate analysis to evaluate the impact of PP on the saturated moisture content of PA-SGRRM. Finally, we employed Scanning electron microscopy (SEM) to observe the microstructures of the low-temperature fracture surface and ambient temperature tensile fracture surface of the PA-SGRRM and employed Fourier transform infrared spectroscopy (FTIR) to deduce the primary chemical reactions occurring within the PA-SGRRM. The results demonstrated that POE-g-MAH played a crucial role in enhancing the compatibility of the simulated hybrid system consisting of PP and PA6. Additionally, it was observed that adhesion between PA6 and asphalt existed, with a gradual decrease as temperature rose. The content of POE-g-MAH and PP were the two primary parameters influencing the performance of PA-SGRRM. POE-g-MAH exerted a significant adverse impact on the flexural strength, tensile strength, and melt flow rate of PA-SGRRM, while substantially improving its low-temperature toughness. The PP positively reduced the water absorption characteristics of PA-SGRRM. Based on the experimental results, the optimal combination of design parameters for PA-SGRRM is recommended.

Electrostatic self-assembly effect of Fe3O4 nanoparticles on performance of carbon nanotubes in cement-based materials

Abstract The beneficial effect of carbon nanotubes (CNTs) to enhance the electrical conductivity and piezoresistivity of cement-based materials was highly contingent upon its dispersion. To achieve an appropriate dispersion of CNTs, ultrasonication, high-speed stirring, and chemical dispersion were commonly used, which raises the risk of structural damage of CNTs caused by the excessive energy. In this study, electrostatic self-assembly of Fe3O4 nanoparticles on CNTs was employed to efficiently disperse CNTs. To optimize the dispersion effect of conductive fillers in cement paste, the mix proportions including sodium dodecyl sulfate (SDS) concentration, CNTs concentration, and Fe3O4/CNTs ratios were adjusted. The dispersion degree and electrical property were evaluated by UV–vis absorption and zeta potential. In addition, the effect of self-assembled conductive filler dosage on the electrically conductive property of cement pastes was examined. The results show that the occurrence of electrostatic self-assembly was proved by the change of zeta potential, and the grape-bunch structure was observed by transmission electron microscopy. Further, the optimal proportions of self-assembled conductive fillers were 0.20 wt% SDS concentration, 0.05 wt% CNTs concentration, and 1:1 Fe3O4/CNTs ratio. The self-assembled conductive filler dosage between 0.02 and 0.10 wt% can effectively improve the electrical conductivity of cement paste with up to 68% reduction of resistivity.

Synthesis of S-scheme 0D/2D Co2ZrO5/g-C3N4 heterojunction photocatalyst with enhanced visible-light photocatalytic activity for tetracycline

The step-like scheme (S-scheme) heterojunction photocatalyst, which possess an improved electric field, intimate interfacial contact and reasonable energy band structure, is one of the most optimal ways to solve the wastewater problem caused by residual antibiotics. Herein, a new type of S-scheme 0D/2D Co2ZrO5/g-C3N4 (CZO/CN) heterojunction photocatalyst was prepared via an ultrasonic assisted hydrothermal method and used as photocatalyst to degrade tetracycline (TC, 20 mg/L, 100 mL). Compared to pure CN and CZO, the CZO/CN with the optimal design proportion (30CZO/CN) demonstrates the outstanding photocatalytic efficiency for TC degradation under visible-light irradiation, with the degradation rate being 94.8 % within 180 min at pH 5.0. Moreover, the 30CZO/CN exhibits superior stability, which still eliminated 90 % of TC after five times cycle runs. Furthermore, the S-scheme mechanism of photocatalytic TC removal by CZO/CN is proposed by XRD, FT-IR, XPS, UV–Vis DRS and PL analysis, which summarized that the enhanced photocatalytic activity of CZO/CN was mainly ascribed to its larger specific surface area, available light absorption region and appropriate bandgap width, dominated by the S-scheme pattern. This study presents a novel S-scheme g-C3N4-base heterojunction photocatalyst can effectively treat wastewater and provides design ideas for other heterojunctions.

Influence of Nano-Fly Ash on mechanical properties, microstructure characteristics and sustainability analysis of Alkali Activated Concrete

Ordinary Portland Cement (OPC) composites significantly affect the atmosphere by emitting Carbon dioxide (CO2) during its production process. The addition of Nano Materials (NM) for the construction could change the matrix configuration at the nano level. Compared to other NMs, converting industrial by-products and locally available materials into nano size can enhance the characteristics of the binder composites. This research work focuses on the effects of Nano Fly ash (nFA), on the fresh, mechanical, microstructural, and thermal resistance properties of Fly Ash (FA) and Ground Granulated Blast Furnace Slag (GGBFS) based Alkaline Activator Nano Concrete (AANC). The impact of adding nFA in various concentrations of 3 %, 6 %, 9 %, 12 %, and 15 % on the properties of AANC was studied. By adding nFA in an optimal proportion, the degree of geo-polymerization is improved which is found by Field Emission Scanning Electron Microscopy (FESEM), X-ray diffraction (XRD), Thermogravimetric analysis (TGA), Energy Dispersive X-Ray Analysis (EDAX) and Fourier Transform Infrared (FTIR). Results indicate that the addition of nFA significantly increased polymerization, reducing initial and final setting times by 13.3 %–52.5 % and 5.3 %–28.8 %, respectively. Moreover, nFA promoted the formation of polymer gel, leading to a denser microstructure with fewer cracks and refined pores, resulting in a substantial increase in mechanical strength, particularly with 9% nFA, achieving an optimal CS of 56.14 MPa after 28 days which is 37.97 % improvement compared to the mix without nFA. However, when nFA was added, beyond 9 %, the performances declined due to its high surface area resulting in a non-uniform dispersion that promoted agglomeration. This dispersion enhances the formation of C-A-S-H and C–S–H gels. The addition of nFA in AANC can be an environmentally friendly solution by reducing CO2 emissions, energy consumption, cost reduction and increased sustainability.