Addition Products Research Articles

High-temperature behaviour of geopolymer composites containing carbon fibre and nano-silica: Mechanical, microstructure, and air-void characteristics

The fly ash–ground granulated blast-furnace slag-based geopolymer (FSG) represents a groundbreaking material, offering a sustainable and environmentally friendly alternative to conventional construction materials. This paper presents a systematic experimental study on FSG reinforced with carbon fibre (CF, 0%–1.0%) and nano-silica (NS, 1%–3%) at high temperatures (20, 200, 400, 600, 800, and 900 °C). Various tests concerning appearance, residual strength, uniaxial tension, XRD, FTIR, TGA, SEM, and air-void characteristics were conducted to analyse thermal effects. The findings show that as temperature increases, the colour of the geopolymer transitions from dark grey to yellow grey. Enhanced geopolymerisation during thermal solidification from 20 to 400 °C significantly increases the compressive, flexural, and tensile strengths of the geopolymer. The addition of CF and NS improves the residual strength of geopolymers at high temperatures, with optimal concentrations found to be 0.6% for CF and 2% for NS. CF maintains its bridging effect at high temperatures, enhancing fibre–matrix bonding, while NS promotes the formation of additional hydration products on CF surfaces, thereby strengthening the material further. After exposure to 800 °C, despite a weakening of the fibre–matrix interface, the modified geopolymers (FSGC0.6 and FSGC0.6N2) exhibit finer air bubble chord lengths and superior air-void characteristics than the control group. This supports the theory that the synergistic action of CF and NS not only enhances geopolymerisation but also fills pores, thus limiting crack propagation and densifying the pore structure.

Transcriptomic data reveals an auxiliary detoxification mechanism that alleviates formaldehyde stress in Methylobacterium sp. XJLW

Methylobacterium sp. XJLW converts formaldehyde into methanol and formic acid via a Cannizzaro reaction in response to environmental formaldehyde stress. Methanol is further assimilated without formaldehyde or formic acid formation, whereas formic acid accumulates without undergoing further metabolism. Synthetic biology-based biotransformation of methanol to generate additional products can potentially achieve carbon neutrality. However, practical applications are hampered by limitations such as formaldehyde tolerance. In this study, we aimed to explore the specific mechanism of strain XJLW in response to formaldehyde stress. Thus, a transcriptomic analysis of XJLW under formaldehyde treatment was performed, revealing changes in the expression of specific genes related to one-carbon metabolism. Central metabolic genes were downregulated, whereas metabolic bypass genes were upregulated to maintain methanol assimilation in XJLW’s response to formaldehyde treatment. In total, 100 genes potentially related to methyl transfer were identified. The function of only one gene, RS27765, was similar to that of glyA, which encodes a methyltransferase involved in one-carbon metabolism. The double-mutant strain, lacking RS27765 and glyA, lost its ability to grow in methanol, whereas the single-mutant strain, lacking only one of these genes, still grew in methanol. Co-expression of RS27765 and RS31205 (YscQ/HrcQ type III secretion apparatus protein) enabled Escherichia coli BL21 (DE3) to effectively degrade methanol. Using protein sequence analysis and molecular docking, we proposed a model wherein RS27765 is necessary for cell growth by using methanol generated via formaldehyde cannizzaro reaction. This process enables direct assimilation of methanol without producing formaldehyde and formic acid as intermediate metabolites. The RS27765 gene cluster, in conjunction with metabolic bypass genes, constitutes a novel auxiliary pathway facilitating formaldehyde stress tolerance in the strain.

The value of healthy ageing: Estimating the economic value of health at older ages using time use data

Abstract While health naturally has intrinsic value and maintaining health as people age seems to make good economic sense, making the case for investing in health at older ages can be challenging. Much economic growth is historically attributed to the working-age population; however, maintaining good health as people age also enables older people to contribute meaningfully to the economy. Investing in health at older ages, therefore, can be strategic economic policy. We develop a novel method to quantify the economic value of health through time use data. Using data from the United Kingdom Time Use Survey (UKTUS) 2014-15 for individuals aged 65 years-old and older, we apply survey-weighted generalized linear models to predict the time spent in non-market productive activities based on age and self-perceived health. We then quantify the monetary value of time spent engaging in these activities and simulate the monetary impact of health gains at older ages. Both age and self-perceived health status were associated with minutes spent in many non-market productive activities. Being in ‘very good’ instead of ‘very bad’ self-perceived health is associated with an additional production of 439£, 629£, and 598£ per month for an average individual aged 65 to 74 years-old, 75 to 84 years-old, and 85 years-old and older, respectively. Our simulation model indicates that improving the health of 10% of older people in ‘very bad’ health could lead to an economic increase of up to 278£ million through non-market activities. Health at older ages creates considerable economic value which is not captured using standard national accounting measures. Our work highlights the importance of health for functional capacity as people age, allowing them to engage more in non-market activities. Our method to quantify the monetary value of health can be adapted to other settings to make the economic case for investing in healthy ageing.

(S)-2-Hydroxyisovalerate Production from d-Xylose with CO-Converting Clostridium ragsdalei

Clostridium ragsdalei was found to produce (S)-2-hydroxyisovalerate (2-HIV) as a novel product in addition to acetate, ethanol, and d-2,3-butanediol in heterotrophic (d-xylose), autotrophic (CO), and mixotrophic (d-xylose + CO) conditions. Mixotrophic batch processes in stirred-tank bioreactors with continuous gassing resulted in improved production of this alpha-hydroxy acid compared to batch processes solely with either d-xylose or CO. The maximal CO uptake rate was considerably reduced in mixotrophic compared to autotrophic processes, resulting in a concomitant decreased total CO2 production. Simultaneous conversion of 9.5 g L−1 d-xylose and 320 mmol CO enabled the production of 1.8 g L−1 2-HIV in addition to 1.1 g L−1 d-2,3-butanediol, 2.0 g L−1 ethanol, and 1.8 g L−1 acetate. With reduced initial d-xylose (3.1 g L−1), l-valine production started when d-xylose was depleted, reaching a maximum of 0.4 g L−1 l-valine. Using l-arabinose or d-glucose instead of d-xylose in mixotrophic batch processes reduced the 2-HIV production by C. ragsdalei. Considerable amounts of meso-2,3-butanediol (0.9–1.3 g L−1) were produced instead, which was not observed with d-xylose. The monomer 2-HIV can form polyesters that make the molecule attractive for application as bioplastic (polyhydroxyalkanoates) or new composite material.

A Multi-Isotopic Chemometric Approach for Tracing Hazelnut Origins

High-value products, such as hazelnuts, are particularly vulnerable to fraud due to their price dependence on geographical origin. Guaranteeing hazelnuts’ authenticity is essential for consumer trust and safety. Stable isotope analysis has become a reference method for origin authentication as it is reliable, robust, and easily transferable across laboratories. However, multiple isotopic markers coupled with chemometric techniques are often needed to authenticate food provenance accurately. In this study, we focused on assessing the potential of bulk δ18O, along with δ2H and δ13C of the main fatty acids, as hazelnut-origin authenticity markers. PLS-DA classification models were developed to differentiate samples (n = 207) according to their region of origin. This multi-isotopic approach provided promising external validation results, achieving a 94% global correct classification rate in discriminating hazelnuts from regions with distinct geographical and environmental conditions. This study lays the groundwork for further model development and evaluation across additional production areas and harvest years.

Pseudomonas aeruginosa in the Frontline of the Greatest Challenge of Biofilm Infection—Its Tolerance to Antibiotics

P. aeruginosa biofilms are aggregates of bacteria surrounded by a self-produced matrix which binds to some antibiotics such as aminoglycosides. P. aeruginosa biofilms are tolerant to antibiotics. The treatment of biofilm infections leads to a recurrence of symptoms after finishing antibiotic treatment, although the initial clinical response to the treatment is frequently favorable. There is a concentration gradient of oxygen and nutrients from the surface to the center of biofilms. Surface-located bacteria are multiplying and metabolizing, whereas deeper located bacteria are dormant and tolerant to most antibiotics. Colistin kills dormant bacteria, and combination therapy with colistin and antibiotics which kills multiplying bacteria is efficient in vitro. Some antibiotics such as imipenem induce additional production of the biofilm matrix and of chromosomal beta-lactamase in biofilms. Biofilms present a third Pharmacokinetic/Pharmacodynamic (PK/PD) micro-compartment (first: blood, second: tissue, third: biofilm) which must be taken into consideration when calculations try to predict the antibiotic concentrations in biofilms and thereby the probability of target attainment (PTA) for killing the biofilm. Treating biofilms with hyperbaric oxygen to wake up the dormant cells, destruction of the biofilm matrix, and the use of bacteriophage therapy in combination with antibiotics are promising possibilities which have shown proof of concept in in vitro experiments and in animal experiments.

Optimizing the user experience of additive manufacturing products through material driven design

Optimizing the user experience of additive manufacturing products through material driven design

Liming acidic soils creates profits, land use options but often more emissions

Context Soil acidity constrains crop production in Australia. The practice of liming can reduce soil acidity but produces greenhouse gas emissions. Aims By examining land use sequences over three decades at a range of locations in Western Australia, this study aims to identify firstly where and when liming might boost farm profits and secondly, what emissions and land use management flexibilities are generated by liming. Methods Bioeconomic simulation modelling is used to identify the gross margins and emissions associated with liming in land use sequences at 14 locations in Western Australia. Three intensities of cropping and three different rotational sequences are considered. The simulations account for price and weather–year variations across a 30-year period of analysis. Key results Liming is profitable at almost all locations and across all rotation sequences examined. Where problematic soil acidity is a feature or is poised to soon become a problem at a location, liming is a profitable ameliorative practice that enables greater diversity in land use. For most situations assessed, liming increases emissions. The exceptions are at locations where liming prevents a switch away from a crop-dominant system, due to soil acidity reducing crop yields, into additional sheep production that increases emissions. Conclusions Liming is profitable in most acidic soil situations and preserves land use flexibility, although additional greenhouse gas emissions are often generated. Implications Liming acidic soils bolsters land use profitability and helps sustain biologically diverse land use sequences, despite often increasing greenhouse gas emissions.

Ice origins of OCS and chemistry of CS2-bearing ice mantles

Abstract Understanding the formation of carbonyl sulfide (OCS) in interstellar ices is key to constrain the sulfur chemistry in the interstellar medium (ISM), since it is the only ice S-bearing molecule securely detected thus far. Two general pathways for OCS formation have been proposed: sulfurization of CO (CO+S) and oxidation of CS (CS+O), but their relative contribution in interstellar ices remains unconstrained. We have evaluated the contribution of both pathways to OCS formation upon energetic processing in isotopically-labeled CO2:CS2 and CO:CS2 ice samples at 7−50 K. Our results indicated that formation of OCS through the CS+O pathway was more favorable than through the CO+S pathway, as previously suggested by theoretical calculations. In addition, its relative contribution increased at higher temperatures. Therefore, this pathway could play a role in the ice formation of OCS, especially in warm regions where CO is expected to be preferentially in the gas phase. At the same time, we have explored the chemistry of CS2-bearing, CO2-, CO-, and also H2O-rich ices, that could be relevant to the sulfur interstellar chemistry. We observed formation of a variety of S-bearing products in addition to OCS, including SO2, C3S2, and S2. However, a significant fraction of sulfur was not detected at the end of the experiments, and could be locked in long, undetectable sulfur allotropes, one of the potential carriers of the missing sulfur in the dense ISM.

Controllable Synthesis of Thioacetals/Thioketals and β-Sulfanyl Ketones Mediated by Methanesulfonic Anhydride and Sulfuric Acid Sulfuric Acid from Aldehyde/Acetone and Thiols.

A novel and controllable synthesis of thioacetals/thioketals and β-sulfanyl ketones mediated by the reaction of aldehyde/acetone with thiols has been developed. In this protocol, β-sulfanyl ketones can be generated without the prior preparation of α, β-unsaturated carbonyl compounds. A variety of thiols reacted with aldehyde/acetone and provided the corresponding thioacetals/thioketals and β-sulfanyl ketones in good to excellent yields, respectively. This protocol is operationally simple, mild, and atom-economical, providing controllable access to thioacetals/thioketals and thia-Michael addition products under mild conditions.

Gold‐catalyzed Annulation between 1‐[2‐(Dimethoxymethyl)phenyl]prop‐2‐yn‐1‐yl Acetates and α‐Diazoesters or Anilines to Form Substituted Naphthoates and Indeno[1,2‐b]quinoline, Respectively.

This work describes gold‐catalyzed annulations of 1‐(2‐(dimethoxymethyl)phenyl)‐1‐prop‐2‐yn‐1‐yl acetate substrates with α‐diazo esters and anilines, respectively yielding substituted naphthoates and indeno[1,2‐b]quinoline derivatives. Our mechanistic analysis indicates 1‐methoxy‐2‐carbonyl‐1H‐indenes as their common intermediates. In the formation of naphthoates, α‐diazo ester attacks at gold‐bound intermediate via a SN2 pathway to enable a allylic methoxy substitution. For indeno[1,2‐b]quinoline derivatives, there are two main reactions, including (i) a reversible formation between intermediate and a double amine addition product and (ii) an arylation reaction of intermediate. Species N‐(phenyl((2E)‐1‐(phenylimino)‐1,3‐dihydro‐2H‐inden‐2‐ylidene)methyl)aniline was converted to indeno[1,2‐b]quinoline in the presence of gold catalyst.

Evaluating the suitability of niches for additive manufacturing production: proposal for a numeric evaluation tool

Additive manufacturing (AM) is a wide set of technologies that can be used for many different scopes. AM is now a well-integrated prototyping and development tool in most industrial endeavours, while proper end-product manufacturing has only seen very specific niche successes. Given the complexity of AM’s matrix, which is full of discontinuities and non-trivial intercorrelations that play a relevant role in product design and development, it should not come as a surprise that not many end-product applications have succeeded in making use of it. This paper argues that understanding AM’s complex matrix and correctly identifying suitable production niches for it are key elements of this issue, a topic for which existing literature and tools are scarce. The analysis of AM’s status quo for end-product manufacturing and the review of existing approaches to integrate these technologies with product development are the basis used in this paper to propose a suitability assessment tool to fill this knowledge gap.

Investigating Hot corrosion, CMAS, and Thermal Shock Behaviour of Double-layer YSZ/La2Ce2O7 + YSZ Thermal Barrier Coatings

AbstractIn this work, new double-layer YSZ/La2Ce2O7 (LC) + YSZ coatings were developed using air plasma spraying (APS). The surface of the prepared coatings was relatively smooth and consisted of melted and partially melted areas. Their resistance to hot corrosion, CaO-MgO-Al2O3-SiO2 (CMAS), and thermal shock were examined. YSZ was added to the upper layer to enhance the lanthanum cerate (La2Ce2O7, LC) properties. During the hot corrosion tests, the corrosion salt reacted with the upper layer, and the CeO2 phase and new corrosion products were identified. The main phase was LaVO4, and the secondary phases were CeVO4 and YVO4. SEM confirmed the formation of new, cuboidal-shaped corrosion products. The infiltration of CMAS led to the formation of additional new products: Ca4MgxAl4Si(6-x-γ)O14 and Ca2.8(LaxCe1-x).6(SiO4)O6-4x. SEM revealed CMAS infiltration through the upper layer in the form of islands. Following the thermal shock resistance tests, the upper layer gradually peeled off, and the coating survived 67 cycles. Possible failure mechanisms were identified, and failure was attributed to the spallation of the upper layer from the surface layer by layer. After all tests, the top layer showed partial spalling and delamination. This was mainly caused by the reaction of corrosive salt or CMAS with the top layer, which changed its composition, leading to the formation and propagation of cracks and, ultimately, the separation of part of the upper layer. Peeling of the upper layer through mainly horizontal cracks was observed after hot corrosion, CMAS and thermal shocks. The NiCrAlY bond coat and YSZ interlayer remained undamaged.

СИСТЕМНІСТЬ РІШЕНЬ РОЗШИРЕННЯ ВИРОБНИЦТВА ВИСОКОЯКІСНОЇ ПРОДУКЦІЇ ЕКСПОРТООРІЄНТОВАНИМ МЕТАЛУРГІЙНИМ ПІДПРИЄМСТВОМ

The study outlines the approaches toward the rationalization of the technological process of pellet production by combining iron ore extraction in the quarry, its milling, concentrate enrichment, pellet firing. The practice of system implementation of modern technology of flotation processing of iron content into the concentrate as a strategic task of improving the quality of pellets is described. The peculiarities of involving a significant percentage of "low-grade" ores in production in case of necessity are revealed. It was concluded that the implementation and successful functioning of the quality management system are affected by engineering mistakes, poor cooperation with suppliers, the return of low-quality products to the enterprise, additional transportation expenses. The sequence of development of the fundamental documents of the quality management system regarding the implementation of the policy in the field of expansion of export supplies of pellets and improvement of the organizational structure of the company's management is covered. The iron content in pellets was predicted using the auto regression model. An improved structure of management of foreign economic activity in case of the implementation of the project on additional production of high-quality pellets is proposed. The costs for increasing the volume of production of iron ore raw materials for the project for the successful functioning of the automated management system for the entire technological process of charge preparation, pelletizing and firing of pellets are systematically defined. A risk assessment was carried out in conditions of implementation of the model for calculating the capital assets of the complex of equipment for the production of high-quality pellets of a well-known global company. Decisions regarding the positioning of the plant's pellets on the world market with determination of the pricing strategy are justified.

Effects of Size and Mechanical Pre-Treatment on Aluminium Recovery from Municipal Solid Waste Incineration Bottom Ash

Municipal solid waste (MSW) is incinerated to reduce the volume and recover energy and materials. The generation of MSW has been increasing over the past few decades due to the increase in population and changing consumption habits. Rising environmental and economic concerns have increased the importance of waste treatment and recovery. Currently, MSW may take three alternate or parallel routes: direct recycling, incineration, or landfill, depending on the country and location. MSW incineration has three products in addition to energy: bottom ash, fly ash, and off-gas. After incineration, bottom ash usually still contains many materials to be recovered, such as glass, ceramics, and metals with a degree of oxidation. This study focuses on aluminium recovery from MSW incineration bottom ash from two different countries. The 2–30 mm fraction of aluminium particles was characterized in terms of its size, shape, and oxide thickness, and its effects on aluminium recovery were investigated. In addition, the ability of mechanical pre-treatment to remove oxides prior to melting was studied. The results were compared with the analytical modeling developed in this study. An increasing particle size and surface area resulted in an increase in aluminium recovery. Mechanical pre-treatment increased the yield for smaller particles to a larger extent than larger particles due to the difference in the oxide/metal ratio.

The interplay among particle packing, binder, and strength: amelioration of ultra-high performance concrete with nanomaterials, a hope or hype?

A Middling quality of concrete exacerbates deterioration that tarnishes structural integrity and leads to dilapidated infrastructures. The significant intent of this work is to develop sustainable Ultra-High-Performance Concrete (UHPC) using nanosilica and nano clay. The factors, such as particle size, shape, and particle packing effect plays a key role in development of eco-friendly UHPC. Elkem Materials Mixture Analyser (EMMA), based on Modified Andreasen and Andersen particle packing theory is employed for mix optimization to attain dense packing with low binder content. UHPC is amalgamated with cement, silica fume, nanosilica, and nano clay in various combinations. The mix combination includes control mix (A0), B1–B3 that holds 1–3% nano silica, and C1–C3 yields 1–3% nano clay. It is inferred, B3 (3% nanosilica) exhibits the highest compressive strength of 118 MPa due to its size, quasi spherical shape, and homogenous dispersion. Consequently, C2 (2% nanoclay) manifest 18 and 33% enhancement in splitting tensile and modulus of rupture due to due to layered shape of nano clay that acts as reinforcement, inhibits cracks, and improves strength Microstructural analysis confirms the formation of additional hydration products with less voids. Thus, synergy of particle size, shape, and packing effect results in sustainable UHPC.

Three-component carbonylative Michael addition of aryl bromides using abundant metal-carbonyl under light

Carbonyl compounds are widely found in various chemical reactions and natural products. Herein, a light-driven carbonylative cross-coupling reaction of bromobenzene was reported. Co2(CO)8 was used as an abundant solid carbonyl source to synthesize various Michael addition products with high yields. This reaction has broad substrates scope with good functional group tolerance. The mechanism study indicated that the reaction is achieved by the formation of benzoyl radical from homolytic C–Co cleavage under irradiation.

Formation of the Interstellar Sugar Precursor, (Z)-1,2-Ethenediol, through Radical Reactions on Dust Grains

In recent years, the continued detection of complex organic molecules of prebiotic interest has refueled the interest in a panspermic origin of life. The prebiotic molecule glyceraldehyde is proposed to be formed from (Z)-1,2-ethenediol, a molecule recently detected toward the G+0.693-0.027 molecular cloud at the galactic center. In this work, we computationally simulate the formation of (Z)-1,2-ethenediol from vinyl alcohol on the surface of amorphous solid water in a two-step synthesis involving an OH addition and an H abstraction reaction. In total, we considered all reaction possibilities of the 1,1- and 1,2-OH addition to vinyl alcohol followed by H abstraction or H addition reactions on the resulting radicals. The combination of these reactions is capable of explaining the formation of (Z)-1,2-ethenediol provided a suprathermal diffusion of OH. We also conclude that our proposed formation pathway is not selective and also yields other abstraction and addition products. Key in our findings is the connection between the adsorption modes of the reactants and intermediates and the stereoselectivity of the reactions.

Nontargeted screening of air samples using TD-GC-HRMS to identify volatile compounds as markers of an industrial plant fire in Rouen, France

An accidental industrial fire happened in Rouen (France) in september 2019 from a plant specialized in the production of mineral oils and engine additives. A few days after, passive sampling of the air was performed on thermodesorption tubes, from 09/30/2019 to 10/07/2019 using Tenax® TA and Carbopack B&X sorbents. Two identical samplings were carried out 18 (2021) and 26 months (2022) after the fire in the same place to evaluate the urban and in-house background noises. Analyses were performed using a thermodesorption gas chromatograph coupled to a hybrid quadrupole Orbitrap mass spectrometer (TD-GC-Q-Orbitrap) in full scan mode. A non-targeted screening allowed to detect thousands of molecules (about 8000 on Tenax® TA and 3000 on Carbopack B&X sorbents) including a large number of hydrocarbons, alkylbenzenes and polycyclic aromatic hydrocarbons in the tubes collected in 2019. But such hydrocarbons were not specific of the fire and then were not identified as industrial fire markers, as their presence were detected in the samples collected in 2021 and/or 2022. However, 22 sulfur-containing compounds were considered as potential markers because they were only detected in the samples collected in 2019 or at significantly higher level than in 2021 and/or 2022 and were detected in samples collected during Laboratory fire of engine oils. Moreover, these compounds were annotated with good confidence level. Among them, the identification of 6 sulfur-containing compounds, 2-acetylthiophene, 2-propionylthiophene, 2,2′-bithiophene, 3,3′-bithiophene, thieno [3,2-b]thiophene and di-tert-butyl-disulfide, and one oxygen-containing compound, 1,3,5-trioxane, was confirmed by injection of corresponding standards.

Effect of Aqueous Electrolyte Composition on Efficiency of Electrochemical Post-Processing of Additive Manufacturing Products from Ti-6Al-4V Alloy Obtained by Selective Electron Beam Melting

The influence of the anionic composition of an aqueous electrolyte on the efficiency of the electrochemical leveling of the initial microgeometry of samples obtained by the selective electron beam melting (SEBM) at the following mode parameters was studied: current density – 20 A/cm2, initial interelectrode gap – 0.3 mm, average speed of electrolyte pumping – 12 m/c. Aqueous solutions of sodium chloride, nitrate, perchlorate and bisalt electrolytes based on them were studied. It was that aqueous solutions of sodium perchlorate have the best microleveling properties among the studied working media, which provides the ability to reduce the parameters Ra and Rz from values of 35 and 180 μm, respectively, to values of 3.2 and 20 μm during electrolysis of 30 s in a direct-flow electrolyzer. It was established that the microgeometry leveling corresponds to the model of the secondary distribution of dissolution rates; two main factors were identified that significantly influenced on the result: polarization of the electrodes and a decrease in the oxidation state of metal ions passing into the solution during electrochemical machining in the vicinity of the depression in relation to the protrusion due to changes in the local conditions of electrolysis. Microetching along grain boundaries in the studied electrolytes was not detected at the accepted parameters of the electrolysis mode.