Simultaneous Addition Research Articles

Inhomogeneous distribution of oxides in various 9Cr ODS alloys and their mechanical performance at room temperature and 650 °C

Oxide dispersion strengthened (ODS) steels have been considered as promising structural materials for fusion reactors. In fabricating ODS steels, homogenous distribution of nano-sized oxides is always expected. In this work, Ti and C were respectively added into the 9Cr alloy with 2 wt% Mn, and the effects of individual Ti addition on microstructure and mechanical performance of ODS alloys are studied. Regularly distributed oxides were revealed in the 9Cr alloys fabricated by hot isostatic pressing (HIP), irrespective of alloying compositions, which indicates the strong interaction between oxides and phase interface. Alloying elements within the matrix can be incorporated into these regularly distributed oxides. Oxide nanoparticles will affect the phase transformation behaviors and the microstructure of as-HIPed 9Cr alloys without oxides is different from that of 9Cr ODS alloys. By performing post-HIP heat treatments, the matrix conditions of 9Cr ODS alloys can be adjusted, and ferritic and martensitic 9Cr ODS alloys are respectively obtained. With tensile tests at room temperature and 650 °C, effects of oxides and matrix conditions on 9Cr alloys were evaluated. It is found that individual Ti addition has a softening effect on the 9Cr alloys, despite that whether oxides are added. Simultaneous addition of Ti and C can improve the strength of 9Cr alloys evidently. Poor ductility at 650 °C is a critical issue for 9Cr ODS alloys, while the 9Cr alloys without oxides have favorable combination of strength and ductility at both room temperature and 650 °C.

The simultaneous addition of chitosan and peat enhanced the removals of antibiotics resistance genes during biogas residues composting

Direct reuse of biogas residue (BR) has the potential to contribute to the dissemination of antibiotic resistance genes (ARGs). Although high-temperature composting has been demonstrated as an effective method for the harmless treatment of organic waste, there is few researches on the fate of ARGs in high-temperature composting of BR. This research examined the impact of adding 5% chitosan and 15% peat on physicochemical characteristics, microbial communities, and removal of ARGs during BR-straw composting in 12 Biolan 220L composters for 48 days. Our results showed that the simultaneous addition of chitosan and peat extended the high-temperature period, and increased the highest temperature to 74 °C and germination index. These effects could be attributed to the presence of thermophilic cellulose-decomposing genera (Thermomyces and Thermobifida). Although the microbial communities differed compositionally among temperature stages, their dissimilarity drastically reduced at final stage, indicating that the impact of different treatments on microbial community composition decreases at the end of composting. Peat had a greater impact on aerobic genera capable of cellulose degradation at thermophilic stage than chitosan. Surprisingly, despite the total copy number of ARGs significantly decreased during composting, especially in the treatment with both chitosan and peat, intl1 gene abundance significantly increased 2 logs at thermophilic stage and maintained high level in the final compost, suggesting there is still a potential risk of transmission and proliferation of ARGs. Our work shed some lights on the development of waste resource utilization and emerging contaminants removal technology.

Sustainable Exploitation of Wine Lees as Yeast Extract Supplement for Application in Food Industry and Its Effect on the Growth and Fermentative Ability of Lactiplantibacillus plantarum and Saccharomyces cerevisiae

Wine lees, the residue left behind after racking or bottling of wine, are predominantly composed of dead yeast cells, ethanol, phenolic compounds, and tartrates. Yeast extract (i.e., commercial yeast extract), a highly nutritious powder derived from commercially cultivated yeast biomass, is commonly used in nutrient media as a nitrogen source. In the context of by-product valorization, wine lees could potentially be used to produce a substitute for commercial yeast extract (CYE). In our study we investigated the growth and fermentative ability of two major winemaking microorganisms, Lactiplantibacillus plantarum and Saccharomyces cerevisiae, in culture media containing a wine lees yeast extract (WLYE) and a CYE. The effects of yeast extract type, concentration, and initial cell concentration (y0) on key kinetic parameters—maximum specific growth rate (μmax), lag phase duration (λ), and maximum cell concentration (ymax)—were evaluated. For L. plantarum, the results showed that using a WLYE led to similar kinetic parameters to those obtained with a CYE, with λ being unaffected by y0 in samples containing a WLYE. For S. cerevisiae, simultaneous addition of both yeast extracts led to increased μmax values (up to 0.136 h−1) compared to individually added yeast extracts, although this negatively affected λ and ymax. Current research on wine lees is mainly focused on using them as a substrate to produce valuable metabolites through fermentation, overlooking the potential industrial applications of the nutrient-rich autolysate. The findings of this study appear promising for the holistic valorization of wine lees, contributing towards the concepts of sustainability and circular economy.

Biological small molecule interface-modification fostering resilient interfacial chemistry for silicon-based anodes

Silicon-based materials, particularly at the microscale, are prone to rapid capacity fade due to substantial volume fluctuations during the charge-discharge cycles, significantly impeding their commercial viability. Constructing a stable solid electrolyte interface (SEI) is an effective means to improve the performances of silicon-based anodes. Here small biomolecules, tryptophan (Trp) and phytic acid (PA), are introduced as interface modifiers to optimize the interfacial chemistry of micron-silicon anodes. By engaging in the SEI formation process, these small biomolecules effectively regulate the chemical composition and mechanical properties of the formed SEI, fostering a more cohesive and durable interface. The simultaneous addition of PA and Trp has been observed to yield a synergistic effect, creating a tightly bonded and resilient SEI that confers markedly improved battery performances upon the co-modified micron silicon anodes. Density functional theory calculations reveal charge interactions between these small biomolecules and silicon particles, facilitating effective adsorption onto the silicon surface. Simultaneous adsorption of Trp and PA on silicon surface can significantly enhance adsorption strength, providing a compelling explanation for the observed synergistic effect of Trp and PA co-modification.

Chlorpyrifos degradation by Shewanella oneidensis MR-1: Characteristics and mechanism analysis

This study conducted a series of experiments to investigate the degradation performance and mechanism of chlorpyrifos (CPF) degradation by Shewanella oneidensis MR-1 (S. oneidensis MR-1). The results showed that the S. oneidensis MR-1 degradation CPF rate was maximized at a salinity of 10 g·L−1, 35 °C, pH 7, and an inoculum amount of 20 %. The simultaneous addition of anthraquinone sodium 2,6-disulfonate (AQDS) and goethite [FeO(OH)] were able to increase the degradation efficiency to 174.12 %. Further, SEM results showed the FeO(OH) surface might provide a dense reaction site for the degradation. XRD and FTIR analysis revealed the hydroxyl group participated in the degradation process. XPS analysis showed that the addition of AQDS and FeO(OH) promoted the conversion of Fe(III) to enhance the degradation of CPF. Meanwhile, metabolites analysis, indicated that S. oneidensis MR-1 regulated its antioxidant capacity by enhancing its amino acid metabolism and lipid biosynthesis to cope with CPF stress. This work could provide new insights for efficient CPF removal in the future.

PSV-26 Effect of addition of Ascophyllum nodosum and Asparagopsis taxiformis, alone or in combination, to an herbage-based diet on in vitro fermentation in continuous culture

Abstract This study investigated the effect of individual or simultaneous addition of two macroalgae species on in vitro fermentation in continuous culture. Four single-flow continuous culture fermentors were fed an orchardgrass herbage-based (orchardgrass; Dactylis glomerata L.) basal diet and randomly assigned one of four treatments: 1) control (CON), no macroalgae addition; 2) Ascophyllum nodosum dosed at 2.5% dry matter (DM; ASC); 3) Asparagopsis taxiformis dosed at 0.5% DM (ATX); and 4) A. nodosum (2.5% DM) + A. taxiformis (0.5% DM) dosed simultaneously (AS+AT). Four experimental periods were conducted in a randomized block design with 7 d of treatment adaptation and 3 d of sample collection. Fermentors were fed 82 g of DM per day in 4 equal feedings. In the last 3 d of each experimental period, daily samples of total effluent were taken for analyses of ammonia N and volatile fatty acids (VFA). Effluent was composited by fermentor and analyzed for DM, ash, neutral and acid detergent fiber, and crude protein. Purine concentrations of effluent and bacterial isolates were determined to estimate partitioning of N flow into feed, bacterial, and ammonia N fractions. Methane (CH4) emissions were measured in each fermentor every 15 min using a Fourier transform infrared gas analyzer, and pH was recorded every 2 min. Data were analyzed using the MIXED procedure of SAS v 9.4 with pre-planned contrasts comparing each individual macroalgae to CON (CON vs. ASC and CON vs. ATX) and comparing A. taxiformis with and without simultaneous addition of A. nodosum (ATX vs. AS+AT). Significance was declared at P ≤ 0.05 and tendencies at 0.05 < P ≤ 0.10. Nutrient digestibilities, CH4 emissions, pH, and N metabolism variables were not affected (P > 0.10) in ASC compared with CON, but total VFA concentration increased (P < 0.05) by 10%. Contrarily, the ATX diet tended (P = 0.61) to have reduced true organic matter digestibility, reduced (P < 0.05) total VFA concentration by 11%, and reduced (P < 0.05) CH4 production by 99.9% versus CON. Simultaneous the combination of microalgae (AS+AT) did not further reduce (P > 0.10) nutrient digestibility or total VFA concentration compared with ATX, and did not change (P > 0.10) the degree of CH4 inhibition. However, A. nodosum did not mitigate (P > 0.10) any of the negative effects on fermentation associated with A. taxiformis, as nutrient digestibilities and N metabolism variables in AS+AT were also not different (P > 0.10) from ATX. While the macroalgae species, A. nodosum and A. taxiformis, led to different fermentation patterns when added individually to continuous culture fermentors, no negative or positive interactions were observed from their simultaneous addition.

Method for evaluation of Streptomyces growth and metabolism in the presence of glyphosate-based herbicide.

The use of pesticides, such as glyphosate, has increased due to population growth and the rising demand for food. Plant growth-promoting rhizobacteria (PGPR), such as Streptomyces, offer a more ecologically friendly alternative to the excessive use of pesticides. However, these bacteria undergo a complex life cycle involving the formation of hyphae, mycelia, and spores, which makes standardizing laboratory cultures challenging. In this context, we tested three methods for cultivating a Streptomyces isolate (CLV322) in the presence of the stressor agent glyphosate, denoted as M1, M2, and M3. These methods involved the simultaneous addition of the herbicide 24-48h after the start of cultivation. We evaluated the growth and cell viability of CLV322 using the 2,3,5-triphenyl tetrazolium chloride (TTC) assay under glyphosate-based herbicide stress (Roundup® Original DI) at concentrations ranging from 0.002 to 7.2mg mL- 1. We also assessed the ability of CLV322 to maintain PGPR characteristics in the presence of the herbicide by quantifying indolic compounds, siderophores, and phenazines. The cultivation method significantly influenced the production of metabolites by CLV322, with M3 yielding more consistent results across the evaluated parameters. Our findings suggest that germinating Streptomyces spores for 48h before introducing glyphosate (M3) enables the analysis of bacterial tolerance to herbicide stress. This methodology may also apply to evaluate other abiotic stresses on Streptomyces strains.

On the analysis of static thermal instabilities occurring in two-phase flow systems

In this study, we investigate a novel type of static thermal instability that occurs in two-phase flow systems. The instability is theoretically and experimentally confirmed to occur for flow boiling micro-channel scenarios and flow condensing scenarios. The theory presented is independent of the evaporator geometry as well as flow boiling/condensing situations. A stability criteria is derived using a Reynolds Transport approach applied to the evaporator of a two-phase pumped loop (TPPL) system. The theory is then validated experimentally using a TPPL containing a parallel micro-channel evaporator. The instability is confirmed with pressure, temperature, and void fraction measurements acquired at the exit of the evaporator. The findings reveal that static thermal instabilities can arise when simultaneous heat addition and reduction in system saturation temperature occurs (or vice versa). The implications of the thermal instability result in dramatic changes in evaporator heat flux, as well as a flow transition from stratified laminar flow to vigorous turbulent flow with high void fractions. By identifying the additional instability mechanisms, this work contributes to enhancing system reliability and predictability of TPPL systems.

Assessment of mercury methylation and methylmercury demethylation potentials in water and sediments along the Wabigoon River system

Monomethylmercury (MMHg) plays a crucial role in the accumulation of mercury (Hg) within aquatic food chains. Since ambient levels of methylmercury are governed by the balance of simultaneous methylation and demethylation processes, determining in situ methylation and demethylation rates is critically important to understand the dynamics of methylmercury in the environment. This is especially important in the Wabigoon River system in Ontario, Canada, which is severely contaminated with Hg by a chlor-alkali facility operating in the 1960s, and still exhibits some of the highest recorded fish mercury concentrations in Canada. This work used a simultaneous addition of isotope enriched Hg and MMHg tracers to ascertain Hg methylation and MMHg demethylation potentials. At the locations investigated for this study, the most favourable conditions for Hg methylation were found at the Hydroelectric dam, being able to transform 4.2 % and 4.4 % of added Hg in water and sediments per day, respectively, to MMHg. This could correspond to 1.9 ng/L and 29 ng/g of new MMHg being produced from current ambient Hg. Clay Lake, which is considered a sink for mercury and exhibiting a seasonal anoxic environment at its bottom waters, also demonstrated significant MMHg generation, being able to produce 2.7 ng/L and 13 ng/g of MMHg per day, respectively. Demethylation rates in sediments of riverbed and wetland locations showed an average half-life for methylmercury of 2.1 days, indicating a rapid turnover of MMHg in the Wabigoon River. However, significantly lower demethylation rates were also measured near the inflow of Clay Lake, where it took up to 144 days for MMHg to decrease by 50 %. Generally, most of the investigated locations downstream of the pollution source displayed the potential to generate methylmercury, which could be distributed throughout the Wabigoon River system and therefore require attention with respect to future remediation activities.

Assessing the interactive effects of microplastics and acid rain on cadmium toxicity in rice seedlings: Insights from physiological and transcriptomic analyses

In heavy metal-contaminated areas, the simultaneous occurrence of increasing microplastic pollution and persistent acid rain poses a serious threat to food security. However, the mechanisms of combined exposure to microplastics (MP) and acid rain (AR) on the toxicity of cadmium (Cd) in rice seedlings remain unclear. Our study investigated the combined effects of exposure to polyvinyl chloride microplastics and AR (pH 4.0) on the toxicity of Cd (0.3, 3, and 10 mg/L) in rice seedlings. The results showed that at low Cd concentrations, the combined exposure had no significant effect, but at high Cd concentrations, it alleviated the effects of Cd stress. The combined application of MP and AR alleviated the inhibitory effects of Cd on seedling growth and chlorophyll content. Under high Cd concentrations (10 mg/L), the simultaneous addition of MP and AR significantly reduced the production of reactive oxygen species (ROS), the content of malondialdehyde (MDA), and the activity of the superoxide dismutase (SOD). Compared with AR or MP alone, the combination of MP and AR reduced root cell damage and Cd accumulation in rice seedlings. Transcriptomic analysis confirmed that under high Cd concentrations, the combination of MP and AR altered the expression levels of genes related to Cd transport, uptake, MAPK kinase, GSTs, MTs, and transcription factors, producing a synergistic effect on oxidative stress and glutathione metabolism. These results indicate that co-exposure to MP and AR affected the toxicity of Cd in rice seedlings and alleviated Cd toxicity under high Cd concentrations to some extent. These findings provide a theoretical basis for evaluating the toxicological effects of microplastic and acid rain pollution on crop growth in areas contaminated with heavy metals, and are important for safe agricultural production and ecological security.

A new application of MoS2@AG@PA prepared by irradiation: Synergizing with magnesium hydroxide to enhance fire safety and other key properties of EVA composites

AbstractTwo‐dimensional molybdenum disulfide (MoS2) nanosheets are seen as highly promising nanofillers for enhancing polymer properties, yet there is a need for methods that are low‐cost, simple, and environmentally friendly to facilitate the large‐scale production of MoS2 nanosheets. Furthermore, it is necessary to functionalize the MoS2 surface to ensure good interfacial compatibility with the polymer matrix. In this study, MoS2@Ag@PA hybrids were created by generating silver nanoparticles directly on the surface of MoS2 via radiation, followed by encapsulation on the surface of MoS2@Ag through the chelating properties of phytic acid. It is significant to note that, due to the excellent lubrication and physical cross‐linking effects of the MoS2@Ag@PA hybrids, adding one part of MoS2@Ag@PA hybrids can enhance the melt flow rate and elongation at break of the ethylene vinyl acetate copolymer (EVA)/MH composites by 140% and 17.3%, respectively. The simultaneous addition of one part of MoS2@Ag@PA hybrids decreased the peak heat release rate, total heat release, and total smoke release of the EVA composites by 48.7%, 42.7%, and 41.2%, respectively. Moreover, the toxic gasses (e.g., CO) generated by burning EVA composites were significantly reduced compared to pure EVA, indicating improved fire safety. This research not only provides significant opportunities for the green mass production of MoS2 nanosheets but also expands their potential applications in high‐performance nanocomposites.

Advanced ternary carbon-based hybrid nanocomposites for electromagnetic functional behavior in additive manufacturing

This study explores the processing and performance of acrylonitrile butadiene styrene (ABS)-based carbon ternary hybrid nanocomposites, incorporating carbon nanotubes (CNT), graphene nanoplatelets (GNP), and carbon black (CB), for applications in electromagnetic compatibility (EMC). The effect of nanocomposite processing on electromagnetic properties was evaluated by varying the mixing protocol, either through direct extrusion with simultaneous addition of all constituents or by preparing a master batch followed by dilution. The impact of nanofiller morphology and processing techniques on the behavior of nanocomposites was systematically investigated. Filaments of these nanocomposites were Additive Manufactured via Material Extrusion, and the resulting parts were evaluated for EMI shielding effectiveness (SE) in the X-band frequency range. The study reveals that the morphology, influenced by the processing strategy, significantly impacts the EMI SE properties of the printed samples. Particularly, ternary hybrids 3/3/3 wt% (CNT/GNP/CB) nanocomposites demonstrate promising electrical (0.003 S/cm), electromagnetic (29 dB of total attenuation), and mechanical performance (elastic modulus of 3080 MPa), with a clear advantage observed in those processed via direct extrusion. These nanocomposites were validated as feedstock filaments for 3D printing, and the printed sample exceeds the injection molded behavior for the composition 3/3/3 wt% (CNT/GNP/CB), achieving 40 dB of total attenuation at 11.8 GHz. The findings contribute valuable knowledge into tailoring nanocomposite formulations for additive manufacturing applications in EMI shielding, providing a nuanced understanding of the interplay between processing strategies, nanocomposite morphology, and resulting material properties.

Phosphorus and selenium compounding mitigates Cr stress in peanut seedlings by enhancing growth homeostasis and antioxidant properties.

Peanut is an economically important crop, but it is susceptible to Cr contamination. In this study, we used peanut as experimental material to investigate the effects of exogenous P, Se interacting with Cr on the nutrient growth and antioxidant system of peanut seedlings by simulating Cr (0μM, 50μM, and 100μM) stress environment. The results showed that exogenous P, Se supply could mitigate irreversible damage to peanut seedlings by altering the distribution of Cr in roots and aboveground, changing root conformation, and repairing damaged cells to promote growth. When the Cr concentration is 100μM, it exhibits the highest toxicity. Compared to the control group P and Se (0 MM), the treatment with simultaneous addition of P + Se (0.5 + 6.0) resulted in a significant increase in root length and root tip number by 248.7% and 127.4%, respectively. Additionally, there was a 46.9% increase in chlorophyll content, a 190.2% increase in total surface area of the seedlings, and a respective increase of 149.1% and 180.3% in soluble protein content in the shoot and roots. In addition, by restricting the absorption of Cr and reducing the synthesis of superoxide dismutase SOD (Superoxide dismutase), CAT (Catalase), POD (Peroxidase), and MDA (Malonaldehyde), it effectively alleviates the oxidative stress on the antioxidant system. Therefore, the exogenous addition of P (0.5 MM) and Se (6.0 MM) prevented the optimal concentration of chromium toxicity to peanuts. Our research provides strong evidence that the exogenous combination of P and Se reduces the risk of peanut poisoning by Cr, while also exploring the optimal concentration of exogenous P and Se under laboratory conditions, providing a basis for further field experiments.

Poly(vinyl chloride) composites reinforced with wood flour and calcinated halloysite

ABSTRACT Hybrid poly(vinyl chloride) composites were prepared by adding calcinated halloysite and wood flour to the PVC matrix by mixing in a molten state. The mechanical (DMTA analysis, tensile strength, strain at break, Young’s modulus, hardness and impact strength) and thermal (thermal stability, Vicat softening temperature and heat deflection temperature) properties of the composites were tested. The plastographometric analysis suggests that simultaneous addition of two fillers of different origins to the PVC matrix results in a longer gelation time and higher torque values than those observed for neat PVC. Moreover, the presence of calcinated halloysite in PVC/wood flour composites leads to the rise of weight loss temperature compared to PVC composites with only wood flour. When added to PVC/halloysite composites, wood flour improves their homogeneity by breaking halloysite agglomerates, which ensures approx. 116% better thermal stability (confirmed in the Congo red test) compared to unfilled PVC. The synergistic effect of the fillers used on the mechanical properties is demonstrated by the 14.4% higher stiffness and 22.5% higher tensile strength of the PVC composites containing wood flour and 5 wt% halloysite compared to the material loaded with wood flour only.

Fe3O4@ZnO Core-Shell Nanoparticles—a novel facile fabricated magnetically separable photocatalyst

The current study proposes a simple and inexpensive technique to synthesise core–shell Fe3O4@ZnO as a promising photocatalyst. An easily scalable original procedure was developed based on sequential and simultaneous addition of Zn2+ and OH– ions to Fe3O4 cores, and preheating and subsequent heating of the reaction medium. The structure of Fe3O4@ZnO core–shell nanoparticles was found to be a sequence of layers including magnetite (Fe3O4), maghemite (γ-Fe2O3), goethite (α-FeOOH), and zinc oxide (ZnO) in (0001) orientation. This layer sequence ensures a smooth transition from the Fe3O4 of the core to the ZnO shell. The synthesis conditions affect layer density and thickness, which can be easily used in adjusting Fe3O4@ZnO properties.Photocatalytic degradation of a model persistent dye (naphthol green B) in the presence of Fe3O4@ZnO nanoparticles reached promising 77 % in 60 min under UV radiation, while Fe3O4 cores showed only 20 %. The wide-gap ZnO layer on the surface of the narrow-gap Fe3O4 provides charge separation and suppresses electron-hole recombination, which drastically increases photocatalytic activity of the material. Separation of the photocatalyst with a magnet showed the same result as that with a centrifuge. All of these findings lead to inexpensive fabrication, effective performance, low toxicity and simple separation of Fe3O4@ZnO.

Influence of Nano-Activated CaCO3-Metakaolin on Early Strength and Microstructure of Cement

The early strength, microstructure, and structure of cement mortar under low-temperature curing conditions were investigated through compressive strength tests, scanning electron microscopy, x-ray diffraction, synchronous thermal analysis (thermogravimetric analysis coupled with differential scanning calorimetry), and nuclear magnetic resonance tests. The study focused on the impact of the single addition of nano-activated CaCO3 (NAC) and the simultaneous addition of metakaolin (MK) on cement mortar. The results indicate that the addition of NAC accelerated the early hydration of cement. At a 1% dosage, the compressive strength increased by 6.84%, 14.77%, and 18.58% at 1 day, 3 days, and 7 days, respectively. When 5% MK was co-added, the compressive strength increased by 15.16%, 27.85%, and 21.66% at 1 day, 3 days, and 7 days, respectively. The combination of NAC and MK accelerated the hydration of cement, refined the products, reduced the porosity, improved the microstructure, and enhanced the early compressive strength of cement-based materials.

Effect of surfactants on the luminescence, bonding, and catalytic properties of CaWO4 spheres

BackgroundThis work focuses on improving the luminescence and catalytic properties of CaWO4 spheres by manipulating their electron density distribution. The goal is to enhance their suitability for optoelectronic applications and to increase their efficiency in degrading the industrial dye methylene blue (MB). The study utilizes a co-precipitation technique and the addition of three surfactants to synthesize phase-pure CaWO4 with a tetragonal crystal structure. MethodsThe synthesis involved a co-precipitation technique with simultaneous addition of three surfactants. Extensive characterization employed various analytical and spectroscopic methods to assess structural, morphological, luminescent, and catalytic properties. Particularly, the use of cetyltrimethylammonium bromide (CTAB) surfactant induced intense green emission around 500 nm attributed to luminescent center WO42−. Solar irradiation evaluated catalytic performance, with CaWO4: CTAB degrading methylene blue remarkably in just 40 min under natural sunlight. Significant FindingsThe research yielded a CaWO4 material, particularly when assisted by the CTAB surfactant, exhibiting intense green luminescence, making it promising for optoelectronic applications. Furthermore, this material demonstrated remarkable catalytic performance in degrading methylene blue under solar irradiation, suggesting its potential in environmental remediation. The study also delved into electron density distribution by examining differences in bond lengths and mid-bond electron density within a single unit cell, shedding light on the material's underlying properties.

The characteristics and mechanism NO formation during hydroxylated fuels/NH3 oxidation in oxy-fuel atmospheres

Oxy-fuel combustion, as an important technology to realize CCUS in the field of combustion, needs to control the generation of pollutants such as NOx while realizing CO2 capture, and the conversion of fuel-N to N2 is crucial. Previous experiments have provided insights into the influence of different atmospheres on NO during oxy-fuel combustion of alcohols. However, the specific reaction mechanism underlying how the atmosphere and hydroxyl fuels impact NO generation through the free radical pool remains unclear. In this study, the formation and reduction of NO during the oxidation of CH3OH/NH3 and C2H5OH/NH3 in O2/CO2, O2/H2O and O2/CO2/H2O atmospheres with oxy-fuel condition were investigated by simulation. In the NO generation stage, different H2O, CO2, O2 and fuel types have little effect on the peak of NO although they change the NH3→NO reaction path. In the process of NO reduction, stage 1 is the main reaction phase of NO→N2, and both CO2 and H2O are beneficial for the reduction of NO. But the reduction of NO by H2O was more pronounced. In the case of simultaneous addition of H2O and CO2, the reducing effect of H2O and CO2 alone on NO was attenuated. On the other hand, the reduction effect exerted by H2O and CO2 was stronger in high than in low oxygen-fuel ratio, stronger in C2H5OH than in CH3OH. The reduction of NO by H2O and CO2 is based on the general equation NO→N2+O2. H2O is used to promote the reaction in the positive direction by consuming O2 to convert it to H and OH, so that more of the element O is converted to OH than O2 to inhibit the production of NO. The CO2 contributes to the formation of less O2 during the reduction of N2 from NO by promoting reaction NO + N→O + N2, while the additional OH increases the "capacity" of O2 in the NO→N2+O2 reaction.

Enhancing workability of high-volume calcined clay blend cement pastes through optimized addition sequences of PCE superplasticizer

The cementitious paste containing a high volume of calcined clay exhibits poor fluidity due to the thixotropic nature of the clay suspension. The study focuses on the impact of the stepwise addition of PCE and protein-based alkaline retarder (PAR) on the rheological properties of cement-calcined clay blends with varying calcined clay replacement levels. The addition sequences included prior addition (PA), simultaneous addition (SA), and delayed addition (DA) of PCE. The blends were evaluated based on their fluidity, rheology, and setting time. The results showed that the DA sequence notably improved the workability of the blends, minimizing the fluidity loss over 60 minutes and reduced the yield stress of the paste by up to 89.8 %. The adsorption of polymers on mineral particles was analyzed by total organic carbon (TOC), X-ray photoelectron spectroscopy (XPS), X-ray diffractometry (XRD) and Zeta potential test to reveal its mechanism. The results revealed a 17 % increase in polymer adsorption with the DA sequence, while the zeta potential of the blend experienced only a slight change. These findings suggest that the sequence of chemical admixture addition can significantly influence the working performance of cement-calcined clay blends. This provides new insights for improving the dispersion performance of these blends and promotes the application of limestone calcined clay cement.

Effect of Ca and Y microalloying on oxidation behavior of AZ31 at high temperature

The microstructure, oxidation behaviour and oxide film morphology of AZ31, AZ31–0.5Ca, AZ31–0.5Y and AZ31–0.5Ca-0.5Y alloys were investigated. The results demonstrate that the oxidation behaviour of all the experimental alloys can be divided into two distinct parts: the incubation zone, which follows a parabolic law, and the non-protective oxidation zone. The resistance to high-temperature oxidation of AZ31 was enhanced by the incorporation of Ca or Y. The outcomes demonstrated that the oxidation behaviour of AZ31 was highly commendable. The observation of the micro-morphology by scanning electron microscopy (SEM) revealed that the presence of calcium (Ca) and yttrium (Y) can reduce the amount and change the shape of the low-melting-point phase of magnesium (Mg) and aluminium (Al) (Mg17Al12). The morphology and composition of the oxide films were analysed, and it was found that the AZ31–0.5Ca and AZ31–0.5Ca-0.5Y oxides are thinner and more dense, and that the failure is in the form of peeling and detachment. Furthermore, it was observed that the oxides of AZ31 and AZ31–0.5Y become loose and porous at high temperatures. The antioxidant capacity of calcium is enhanced by increasing the film density, while yttrium enhances the resistance to high-temperature oxidation by depleting the low-melting phase and changing the nature of α-Mg. The simultaneous addition of Ca and Y results in cracking and peeling of the film layer.