Influence Of Different Additives Research Articles

Influences of additives on the properties of geopolymer matrix composites (GMCS) for high-temperature applications (1150 °C)

In this study, the influence of different additives on a geopolymer matrix composite (GMC) was explored as an alternative to a ceramic matrix composite (CMC) for thermostructural applications. Different GMCs using an N610 textile (10 × 10 cm2) and various additives (SrCO3, BaCO3, BaSO4, MgO and Al2O3 and mullite-rich powder) were cured under 6 MPa at 120 °C for 2 h. The mechanical, microstructural and structural data of the composites were compared with those of the geopolymer matrix after thermal treatment at 1150 °C. The results showed that the addition of alkali-earth barium carbonate or sulfate to the geopolymer matrix facilitated the formation of alkali-earth aluminosilicate crystalline phases and a higher viscous flow apparition temperature (990 °C), which did not enhance its mechanical properties (50 MPa) due to poor impregnation of the textile. Refractory additives such as MgO and Al2O3 in the geopolymer matrix support fiber impregnation with a low-viscous-flow apparition temperature (865 °C) and the formation of crystalline phases such as forsterite, spinel and sapphirine, which act as reinforcements, allowing a flexural strength up to 80 MPa. The addition of a refractory compound, such as mullite, leads to better embedding of fibers and a flexural strength reaching 100 MPa. To conclude, mixing the geopolymer matrix with refractory compounds results in a successful thermo-structural geopolymer composite.

Review on Research Progress of Geopolymer Concrete

Geopolymer concrete has emerged as a promising alternative to traditional Portland cement - based concrete due to its reduced environmental impact, improved mechanical properties, and potential for sustainable construction practices. This paper presents a comprehensive review of recent advancements in geopolymer concrete technology, focusing on key research findings, innovative materials, and novel applications. A systematic analysis of 40 selected research articles is conducted to elucidate the progress made in the field, covering topics such as material composition, mechanical properties, durability, sustainability, and structural performance. The review highlights the diverse range of materials used in geopolymer concrete, including fly ash, metakaolin, recycled aggregates, and various fibers. Furthermore, it examines the influence of different additives, curing methods, and mix design parameters on the properties of geopolymer concrete. The paper also discusses emerging trends such as the incorporation of hybrid fibers, utilization of waste materials, and development of high - performance geopolymer composites. Finally, future research directions and potential challenges in the widespread adoption of geopolymer concrete are outlined, aiming to contribute to the advancement of sustainable construction practices worldwide.

Influence of different additives on the morphology, defect state and luminescence of ZnO nanoparticles

Zinc oxide (ZnO) is an important multifunctional material with applications in various environmental, drug delivery, sensing, and optoelectronics domains. Binding of different molecules on ZnO enhances the properties and characteristics of nanoparticles through surface modification. In this study, varieties of ZnO nanoparticles (ZnO-NP) are prepared using different additives via simple, low-cost precipitation technique at room temperature. The surface state of ZnO-NP was controlled by three surfactants and two silanes, namely: cetyltrimethyl-ammonium bromide, tween 20, heptaethylene glycol monododecyl ether, 3-aminopropyl triethoxysilane, and tetraethoxysilane. The modified ZnO samples were characterized by various analytical techniques, X-ray diffraction, Raman, FT-IR spectroscopy, surface area analysis and electron paramagnetic resonance. The surface area of the samples significantly increases when silanes are used during the synthesis. Scanning electron microscopy shows the formation of either rounded nanoparticles or layered structures. Depending on the type of additives the zeta potential of colloids increase from 25.92 mV up to 40.36 mV. In this study we show that the chemical nature of additives and the stability of colloids play an important role in the generation of luminescent radiative processes. The green luminescence of ZnO colloids is either enhanced or quenched due to the interaction of additives with the particles surface through covalent, electrostatic, and hydrogen bonds. The ZnO surface becomes more or less permissive toward the movement of surface defects, with formation of oxygen vacancies (VO+ and VO++) responsible for the luminescent response.

Effects of Metal Chloride Salt Pretreatment and Additives on Enzymatic Hydrolysis of Poplar

Metal chloride salt pretreatment was performed to isolate and convert cellulose to glucose from poplar. A glucose yield of 82.0% ± 0.7 was achieved after 0.05 mol/L AlCl3 pretreatment conducted at 180 °C for 20 min, ascribing to the removal of hemicellulose, the alteration of crystallinity, surface morphology, and the retention of the majority of cellulose. Then, the influence of different additives on glucose yield was assessed, generating the highest glucose yield of 88.5 ± 0.06 with the addition of PEG 8000. Meanwhile, a similar glucose yield of 82.8% ± 0.3 could be obtained with PEG 8000 when hydrolysis time was reduced by a quarter and enzyme dosage by three-quarters. It can be seen that AlCl3 pretreatment is a viable and efficient pretreatment method for poplar, while the addition of PEG 8000 can enhance the enzymatic efficiency and reduce cellulase loading, ascribing to the reservation of free enzyme and enzyme activity in the supernatant and the reduction in surface tension, which provide an idea to improve the economics of the enzymatic conversion of poplar.

Pore structure regulation and continuous preparation with VNIPS process of membranes for bioseparation

Ultrafiltration technology has found widespread application in bioprocessing, particularly in protein concentration and buffer exchange for downstream processes. The demand for this technology has spurred research efforts to develop excellent membrane structures with superior separation functionality. However, challenges persist in transitioning laboratory research to industrial-scale continuous production processes while simultaneously optimizing membrane structure and performance through a single fabrication method. Thus, there is an urgent need for pilot-scale membrane preparation to improve membrane morphology and separation efficiency while ensuring scalability. This study investigates a continuous membrane fabrication method, systematically exploring the influence of different additives and vapor-assisted nonsolvent induced phase separation (VNIPS) on the structure and performance of polyethersulfone (PES) membranes. Evaluations of PES membranes with distinct structures were performed, employing flux decline, resistance analysis, and alkali resistance tests to distinguish their performance and bioseparation capabilities. The results showed that good sponge-like pore structure was obtained by VNIPS process, which realized the synergistic optimization of permeation and retention properties. Besides, the sponge-like porous structure membranes prepared by amphiphilic copolymer additives are more suitable for bioseparation.

Influence of different additives on the creep property of oil well cement

As the exploitation of oil and gas field becomes more difficulty nowadays, severe casing deformation may occur if anti-extrusion strength of casing decreases to a certain degree and this brings large economic loss and severe safety problems. As an annular sheath between casing and formation, creep of oil well cement paste is one of the most important factors in deciding abnormal casing deformation and wellbore integrity. To figure out the mechanism on how to reduce the creep value of oil well cement paste, effect of different additives, e.g., retarder, glass fibre reinforcement and CSA expansive agent on the creep value of oil well cement are investigated in this study. It can be found out that retarder plays a negative role in reducing the creep deformation and creep value of cement with 1, 2, 3% retarder is 2.39%, 7.85%, and 15.02% higher than that without retarder at 12 h. Results from heat flow indicates that retarder may play an important role in prolonging the early induction period of hydration and reducing the hydration rate in the middle and later stages. On the contrary, Glass fibre shows a positive effect in reducing the creep value of oil well cement paste and creep value reaches with 0.2%, 0.4%, 0.6%, and 0.8% is 1.27%, 6.61%, 9.82%, and 12.60% lower than that without fibre addition at 72 h. This is because high porosity between and around fibers based on a microstructure observation may lead to a more continuous and uniform stress field between cement paste, and consequently reduce the creep value of cement paste. It can also be found out that CSA cement is considerably effective in limiting creep deformation of oil well cement paste at early ages. There is also an acceleration effect on the heat flow of oil well cement in both induction and acceleration periods and the corresponding maximum heat flow is 7.3%, 9.0%, and 11.2% higher than the reference cement with no CSA addition. The results obtained in this study are aimed to provide theoretical basis for the wellbore integrity and improvement of oil and gas recovery.

Flower-like superhydrophilic and superaerophobic B-doped NiMoO4@NF as self-supported electrode for highly efficient hydrogen evolution

Designing cost-efficient and high activity electrocatalysts for hydrogen generation is significant for the large-scale and sustainable energy conversion. Herein, non-metallic boron (B) doping strategy was used to prepare self-supported electrode (B-NiMoO4@NF) which possessed flower cluster structure and was rich in oxygen deficient, and the influence of different addition of NaBH4 on catalyst performance was also investigated. Experimental studies showed that with the increase of NaBH4 addition, the morphology and structure of NiMoO4 precursor changed from "cuboid to hollow tubular to porous tubular". At the same times, numerous oxygen defect sites were generated that further increased the catalytic specific surface area and exposed more catalytic active sites. The results of surface wettability test showed that the prepared B-NiMoO4@NF electrodes exhibited superhydrophilic and superaerophobic properties, and B10-NiMoO4@NF electrode showed better HER catalytic performance than commercial Pt/C supported by nickel foam (Pt/C@NF). And it merely required an overpotential of 22.89 mV to achieve the current density of 10 mA cm−2 and the low Tafel slope of 30.08 mV dec−1 in 1.0 M KOH solution. Besides, the electrode also exhibited excellent HER stability at the high current density of the electrode (500 mA cm−2).

Influence of different additives on the rheology and microstructural development of MgO–SiO2 mixes

Development of alternative binder systems to be used in additive and automated manufacturing technologies is crucial for increasing the sustainability and productivity of the construction process . Advancements in this area facilitate shorter construction durations, enhanced resource efficiency and reduced construction waste; enabling complex, high-quality and functional designs that would not be possible with traditional methods. The novelty of this work involves the demonstration of the properties of a promising alternative binder, reactive MgO–SiO 2 (RMS) binder, that can highlight its feasibility to be used in large-scale applications and the identification of the effects of different phosphate additives during this process. RMS mixes containing three different phosphate additives (sodium hexametaphosphate, trimetaphosphate and orthophosphate (OP)) were analyzed for their pH, reaction kinetics, workability, mechanical performance and rheological properties to reveal the influence of these additives on the properties of RMS mixes. These findings were supported by FTIR, 29 Si MAS NMR and XRD measurements. The inclusion of OP in RMS binder systems increased the pH of solution, thereby improving the dissolution of silica and its reaction with Mg-phases and resulting in enhanced magnesium-silicate-hydrate (M-S-H) formation. These improvements in hydration mechanisms translated into better mechanical performance and rheological properties, which can correlate to desirable properties for 3D printing applications.

Influence of the fitting rule of Extended Depth of Focus contact lenses on visual performance of high addition presbyopic patients

Purpose: Recommended fitting rule for Extended Depth of Focus (EDOF) contact lenses is to use medium addition in the non-dominant eye and high addition in the dominant eye when spectacle addition is higher or equal to 2.00D. The purpose of this study was to evaluate the influence of different additions in the optical performance of high addition presbyopic patients with EDOF contact lenses through defocus curves.

A novel expansive soil hardener: performance and mechanism of immersion stability.

Aiming at the existing problems of poor treatment effect and immersion stability of expansive soils, a slag soil hardener (SSH, developed by Wuhan University, China) was combined with different additives to dispose in this study. The free expansion rate, compressive strength, and immersion stability of samples were compared, and the influences of different additives, curing age, and dry density on the process and mechanism of improvement were discussed. The experimental results indicated that SSH combined with quicklime had the best improvement effect on expansive soils, in which the mass ratio of raw materials was: expansive soil/SSH/quicklime = 92/4/4, and the free expansion rate decreased from 45.90% to 4.4%, compressive strength increased from 2.53 MPa to 6.69 MPa, and there was no splitting after immersion under this ratio. FTIR spectroscopy, XPS and SEM were performed to analyze the characteristic functional groups, structural forms, and morphology of samples to study the mechanism of improvement, which showed that SSH greatly reduced the proportion of montmorillonite in the whole system and further enhanced the mechanism of ion exchange, soil particle connection, and coating protection. The research can provide theoretical reference for engineering the application of expansive soil area in rainy climate and has dual economic and environmental benefits.

Morphological Analysis and Properties Evaluation of Electrodeposited Thick BiSbTe Films with Cooperative Interactions among Multiple Additives

As a cost-effective method, electrodeposition has been widely applied to synthesize materials for the fabrication of micro thermoelectric devices. However, it is hard to obtain smooth, compact and high-performance p-type BiSbTe films when the thickness becomes higher. In this work, multiple additives consist of PVA and saccharin sodium are firstly introduced into the electrolyte bath with the assistance of KCl for electrodeposition. The influence of different additives on reduction kinetics, morphology, stoichiometry and crystalline structure has been thoroughly explored. Besides the electrolyte concentration and the deposition potential, the pulse duration for pulsed deposition also significantly affects the stoichiometry. The smooth, compact and well-adherent films with ideal composition were successfully deposited for the thickness range from 4 to 100 μm. Crystallite size was much refined, and lattice strain slightly increased with the cooperative reaction of multiple additives. The measured Seebeck coefficient reached around 262 ± 25 μV K−1 for the deposited film with multiple additives, while that of the film with absence of additives was about 156 ± 14 μV K−1. The electric resistivity increased from 66 μΩ·m to 150 μΩ·m when PVA and saccharin sodium were introduced, but decreased to 81 μΩ·m after increasing the electrolyte conductivity through adding KCl.

Incorporation of zirconium into PEO coating on Ti6Al4V alloy from acidic electrolyte

<abstract> <p>To imitate the superior biocompatibility of Ti–Zr alloys at reduced cost, conventional Ti6Al4V alloy was modified via plasma electrolytic oxidation (PEO). The influence of different additives on the phase composition and topography was investigated in acidic electrolytes containing Zr(SO<sub>4</sub>)<sub>2</sub>·H<sub>2</sub>O with potentiostatically controlled PEO at different pulse frequencies. Apart from the primary intention to generate Zr enriched phases, formation and incorporation in the ceramic layer of potential antibacterial Cu and Zn species was achieved and examined by X-ray diffraction. The thickness of the oxide layer, the adhesion and the layers' composition were evaluated using FIB and SEM-EDX.</p> </abstract>

Modification of Alumina Inclusions in SWRS82B Steel by Adding Rare Earth Cerium

The aluminum oxide inclusions in SWRS82B steel seriously affect the drawing performance of the steel strand. In this study, the influence of different additions of cerium (within the range of 0–0.034%) on the composition, morphology, size, number, and distribution of alumina inclusions was studied by scanning electron microscope and energy spectrum analyzer. The evolution of the composition of inclusions with different cerium additions was calculated based on classical thermodynamics and Factsage software calculation. The thermodynamic calculated results were consistent with the experimental results. It indicates that the modification route of Al2O3 inclusions in SWRS82B steel by increased cerium additions is as follows: Al2O3 → Ce2S3 + CeAlO3 + Ce2O2S + Al2O3 → Ce2S3 + CeAlO3 + Ce2O2S/Ce2S3 + Ce2O2S → Ce2S3 + Ce2O2S. Besides, when the amount of cerium is in the range of 0.023% to 0.030%, CeAlO3 inclusions gradually disappear. The best characteristics of inclusions in this study were obtained in experimental samples with cerium addition of 0.023%, in which the minimum size of inclusions is in the range of 3.52–4.84 μm and mostly uniform distribution. Finally, the mechanism on the modification by cerium was discussed based on the composition evolution of inclusion during solidification with Factsage calculation and experimental results. The compositions of inclusions were also analyzed based on the inclusion evolution model.

Vpliv različnih dodatkov na mehanske lastnosti a-hemihidratnega mavca sintetiziranega iz fosfatnega mavca

Vpliv različnih dodatkov na mehanske lastnosti a-hemihidratnega mavca sintetiziranega iz fosfatnega mavca

Effects of sintering additives on hot corrosion behavior of γ-Y2Si2O7 ceramics in Na2SO4+V2O5 molten salt

Dense γ-Y2Si2O7 ceramics were prepared by moulding and sintering of pure γ-Y2Si2O7 powders synthesized by adding various additives. Effects of sintering additives on hot corrosion behavior of γ-Y2Si2O7 ceramics in Na2SO4 + V2O5 molten salts were systematically investigated. Chemical kinetics of corrosion process was also calculated to illuminate the influence of different additives on chemical stability. Results showed that corrosion reaction started at grain boundary due to the loose microscopic network. When the intercrystalline glass phase was completely etched, the molten salts began to contact Y2Si2O7, forming NaY9Si6O26 and YVO4. Compared with Li2O and MgO, intercrystalline glass phase formed by Al2O3 additive had the most compact microscopic network structure, leading to the best chemical stability. Apparent activation energy for hot corrosion reaction of γ-Y2Si2O7 ceramics in pure Na2SO4, Na2SO4 + 5 wt% V2O5, Na2SO4 + 10 wt% V2O5, Na2SO4 + 15 wt% V2O5 molten salts was calculated to be 408.16, 373.60, 310.62, and 249.63 kJ/mol, respectively.

The influence of different additives on microstructure and mechanical properties of aluminum titanate ceramics

The aluminum titanate (AT: Al2TiO5) ceramics with different additives, including SiO2, MgO, Fe2O3 and their mixture, were prepared by reaction sintering at 1500 °C in air for 2 h. The influence of additives on the microstructure and flexibility of AT ceramics is studied. Research illustrates that additives, MgO, Fe2O3 and their mixture, can be dissolved in AT ceramics to promote the formation of elongated grains and grain boundary microcracks. The elongated grains can interlock together and restrain crack propagation while microcracks can provide gaps for grains to move, leading to obvious flexibility of sample. Especially, the AT ceramics doped with MgO and Fe2O3 (ATFM) show the optimum flexibility with a deflection about 0.55 mm and strength up to 13.85 MPa. While the additive of SiO2 can reduce the size of grains and microcracks, resulting in high mechanical strength but poor flexibility. The successful fabrication of such AT flexible ceramics will provide potential opportunity for anti-vibration and refractory application.

Experimental Comparative Study of Effect of Different Additive Materials on Concrete Mix Alkalinity and Heat Generation

There are different methods to minimize the evolution of heat in concrete. Since the cement is the main component that generates heat, the first procedure may be to reduce its quantities by replacing cement with fine materials that do not release heat during its reaction. This paper studies the influence of different additives (fly ash, silica fume, and metakaolin) to the concrete mixture with different ratios of (0, 5, 10, 15, 20, 25, 30%) by weight of cement, with different parameters study, were presented, including impact of additives on (compressive strength, alkalinity, heat of hydration with fixed w/c ratio of 0.35, initial setting time, final setting time and impact of w/c ratio on heat of hydration with three w/c ratio of (0.3, 0.35 and 0.4)). The water cementations materials ratio was kept steady at (0.35). The heat of hydration measurement was carried out under isothermal constrain(25±0.1C°). Thermocouples were utilized to evaluate the heat of hydration of concrete by stating time from 0 to 24 hours and measured by a thermoelectric device. Concrete cubes with dimensions 100×100×100 mm for compressive strength test were used and examined at the time of 28 days, using different mix proportions resulted from different percentages of cement additives, to perform the compressive strength test. The results revealed that the Portland cement heat of hydration is retarded in the presence of additives. The decrease in pH of the concrete mix before casting and molding affects the early hydration and strength but improves the later age concrete properties.

Improvement in hydration resistance of CaO granules based on CaO–TiO2, CaO–ZrO2 and CaO–V2O5 systems

In this paper, CaO granules were prepared, using the slaked lime as the raw material as well as ZrO2, TiO2, and V2O5 as additives, respectively. The influence of different additives on the sintering properties, microstructure and hydration resistance of CaO granules was investigated. The results indicated that the introduction of additives could obviously promote the densification and the hydration resistance of the specimens. Especially, the sintering mechanisms of the specimens with different additives were studied. For the specimens with ZrO2 and TiO2 as additives, the in-situ formed CaZrO3 and Ca3Ti2O7 between grain boundaries promoted the densification to enhance the properties of the granules. However, the adding of V2O5 generated a coating on the surfaces of CaO granules which contributed to the best hydration resistance.

Influence of Additives on the Reversible Oxygen Reduction Reaction/Oxygen Evolution Reaction in the Mg2+ -Containing Ionic Liquid N-Butyl-N-Methylpyrrolidinium Bis(Trifluoromethanesulfonyl)imide.

The influence of different additives on the oxygen reduction reaction/oxygen evolution reaction (ORR/OER) in magnesium‐containing N‐butyl‐N‐methylpyrrolidinium bis(trifluoromethanesulfonyl)imide ([BMP][TFSI]) on a glassy carbon electrode was investigated to gain a better understanding of the electrochemical processes in Mg–air batteries. 18‐Crown‐6 was used as a complexing agent for Mg ions to hinder the passivation caused by their reaction with ORR products such as superoxide and peroxide anions. Furthermore, borane dimethylamine complex (NBH) was used as a potential water‐removing agent to inhibit electrode passivation by reacting with trace impurities of water. The electrochemical processes were characterized by differential electrochemical mass spectrometry to monitor the consumed and evolved O2 in the ORR/OER and determine the number of transferred electrons. Crown ether and NBH efficiently masked Mg2+. A stochiometric excess of crown ether resulted in reduced formation of a passivation layer, whereas at too high concentrations the reversibility of the ORR/OER was diminished.

English

This study aims to evaluate the influence of different additives, including natural additives such as olive oil and eggs, on repair and restoration mortars. This work enables us to verify the effects of these natural components and their impact on the physical and mechanical characteristics of various types of repair mortars. Four mortar formulations were developed and analysed: Two jointing mortars, including the control sample MF1, without additives; and two finishing mortars (plaster). The physical and mechanical analysis of these different mortar samples showed that each additive had effects on the durability, percentage of absorption and porosity of the samples, as well as on their water repelling, and waterproofing properties. The control sample MF1 had the highest content of total porosity and water absorption. In the other samples, the water absorption and porosity contents decreased with an increase in the quantity of crushed bricks. In addition, sample MF3, which contained two volumes of crushed bricks per one volume of lime and an addition of 5% olive oil, had the lowest water absorption and porosity content and the highest resistance to compression and bending. The results obtained demonstrate that the mortars with natural additives MF3 and MF4 have reduced rate of water absorption, porosity, and water absorption by capillarity than control mortars (MF1) and samples with only crushed bricks added (MF2). Key words: Repair mortar, natural additives, compatibility, crushed brick, olive oil, eggs, water repellent, durability.