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Paper is susceptible to chemical degradation through hydrolysis and oxidation, resulting in embrittlement and failure. Understanding the embrittlement process is important to ensure the preservation and longevity of historical paper-based documents. However, the complex and architectured paper microstructure is a major challenge for fully understanding this process. Two papers with different microstructures were artificially aged under hydrolytic and oxidative exposure conditions, and the consequences of ageing were studied. The fibre embrittlement, the fibre–fibre bonds deterioration, and the evolution of paper microstructure upon ageing are evaluated through macroscopic and localised mechanical tests, as well as through morphological observations at the microscopic scale. It was concluded, from the different tests in the two principal orientations of the paper, that fibre embrittlement plays a more significant role in the embrittlement process than fibre–fibre bonds deterioration. Specifically, the cellulose chain scissions led to fibre embrittlement, irrespective of the oxidative or hydrolytic nature of the chemical degradation mechanism. Furthermore, we identify a critical degree of polymerisation for cellulose (DPc ~ 750) below which the evolution of mechanical properties accelerates significantly, regardless of the type of mechanical testing performed. Fibre analysis suggests that the decline in fibre resistance results in fractures occurring under stress at weak points of the fibres, such as kinks or twists. [ABSTRACT FROM AUTHOR]

Copyright of China Pulp & Paper is the property of China Pulp & Paper Magazines Publisher and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In order to investigate a synergetic role of water and oxygen in the degradation of permanent paper in archiving climate, accelerated ageing in three different conditions was conducted: humid air, humid nitrogen and dry air. This allowed to decouple acid-catalysed hydrolysis versus oxidation of cellulose. After ensuring the reliability of the ageing experiment, the degradation state of the paper was assessed. Various techniques (size exclusion chromatography, pH extraction, alkaline reserve, paper colour and water content) were used. It appeared that the cellulose scission rate of the Canson® permanent paper was reduced compared to the Whatman No. 40 acidic cotton paper used as reference, but not in the same proportion for all the ageing conditions. This was attributed to a lower acidification, inhibiting acid-catalysed hydrolysis, due to the presence of the alkaline reserve. The degradation mechanisms are the same for both papers, which exhibited a similar chemical and physical degradation. [Display omitted] [ABSTRACT FROM AUTHOR]

The degradation of paper is due to complex physical and chemical processes that occur as the paper ages, and is enhanced by environmental factors, such as the temperature and relative humidity, and by intrinsic parameters, such as the acidity of the paper. The literature reports that a large percentage of historic documents, manuscripts, and paper objects in museums, libraries and collections is susceptible to degradation phenomena, which may ultimately affect their integrity and longevity. This contribution presents a novel computational model to predict the degradation and lifetime of historic paper. The approach is based on: i) a multi-physics modelling framework, which considers the relevant chemical and mechanical degradation processes and the influence by the ambient environmental conditions, and ii) a multi-scale description, which includes the effect of the intrinsic hierarchical structure of paper, from the fibre- and fibrous network levels to the effective macro-scale, paper sheet level. The paper fibres constructing the fibrous network are characterized by an age-dependent, chemo-mechanical constitutive behaviour. In particular, an evolution equation describes the reduction of the degree of polymerization of cellulose as a function of time and the specific environmental conditions, which in turn is used for determining the fibre tensile strength. The fibre stresses induced by hygro-expansion and hygro-contraction under a change in relative humidity are computed using a coupled hygro-mechanical model, and lead to brittle damage once the fibre tensile strength is reached. Accordingly, the chemical degradation of individual fibres affects the local damage development and stress distribution in the fibrous network, and thereby governs the material response at the paper sheet scale. Asymptotic homogenization is used to calculate the effective hygro-mechanical properties of the fibrous network. A set of numerical simulations is performed to predict the time-dependent degradation of historic paper under a range of temperature, relative humidity and acidity conditions. From these results, isochrone degradation maps are constructed that illustrate the expected lifetime of historic paper as a function of the ambient climate conditions and the acidity of the paper. Further, a practical, analytical degradation function is derived that can be used for a fast estimation of the time-dependent stiffness degradation of paper. The outcome of this work may help conservators to determine the optimal indoor climate conditions in museums, archives and libraries for limiting or delaying time-dependent degradation of historic paper artefacts. [ABSTRACT FROM AUTHOR]

Poly-(meta-phenylene isophthal-amide) (PMIA) is regarded as an ideal insulating medium for electronic devices owing to its excellent chemical stability and breakdown strength. However, the poor thermal conductivity limited the application under complex electrical-thermal environment. In this work, the size-graded AlN/PMIA composite papers were fabricated, with a multi-scale structure of matrix and fillers, and maintain qualified stability, mechanical strength and electrical insulation properties. With doping 40 wt% of 10 μm AlN and 10 wt% of 200 nm AlN, the optimum paper with in-plane (λ ∥) and out-of-plane (λ ⊥) of optimal paper reached thermal conductivity of 17.3 W/(mK) and 1.96 W/(mK) is obtained, and the breakdown strength increased to 69 kV/mm. The improvement mechanism brought by size-graded fillers was further revealed by the co-simulation of finite element method and loop nesting algorithm. [Display omitted] [ABSTRACT FROM AUTHOR]

The global net emissions of the Kyoto Protocol greenhouse gases (GHG), such as carbon dioxide (CO2), fluorinated gases, methane (CH4), and nitrous oxide (N2O), remain substantially high, despite concerted efforts to reduce them. Thermal treatment of solid waste contributes at least 2.8-4% of the GHG in part due to increased generation of municipal solid waste (MSW) and inefficient treatment processes, such as incineration and landfill. Thermal treatment processes, such as gasification and pyrolysis, are valuable ways to convert solid materials, such as wastes into syngas, liquids, and chars, for power generation, fuels, or for the bioremediation of soils. SubcoalTM is a commercial product based on paper and plastics from the source segregated waste that is not readily recyclable and that would otherwise potentially find its way in to landfills. This paper looks at the kinetic parameters associated with this product in pyrolysis, gasification, and combustion conditions for consideration as a fuel for power generation or as a reductant in the blast furnace ironmaking process. Thermogravimetric Analysis (TGA) in Nitrogen (N2), CO2, and in air, was used to measure and compare the reaction kinetics. The activation energy (Ea) and pre-exponential factor A were measured at different heating rates using non-isothermal Ozawa Flynn Wall and (OFW) and Kissinger-Akahira-Sonuse (KAS) model-free techniques. The TGA curves showed that the thermal degradation of SubcoalTM comprises three main processes: dehydration, devolatilization, and char and ash formation. In addition, the heating rate drifts the devolatilization temperature to a higher value. Likewise, the derivative thermogravimetry (DTG) results stated that Tm degradation increased as the heating rate increased. Substantial variance in Ea was noted between the four stages of thermal decomposition of SubcoalTM on both methods. The Ea for gasification reached 200.2 ± 33.6 kJ/mol by OFW and 179.0 ± 31.9 kJ/mol by KAS. Pyrolysis registered Ea values of 161.7 ± 24.7 kJ/mol by OFW and 142.6 ± 23.5 kJ/mol by KAS. Combustion returned the lowest Ea values for both OFW (76.74 ± 15.4 kJ/mol) and KAS (71.0 ± 4.4 kJ/mol). The low Ea values in combustion indicate shorter reaction time for Subcoal™ degradation compared to gasification and pyrolysis. Generally, TGA kinetics analysis using KAS and OFW methods show good consistency in evaluating Arrhenius constants. [ABSTRACT FROM AUTHOR]

Albumen prints are the most important photographic prints of the late 19th century. It is basically composed of two layers: the first layer is the paper support (i.e. cellulose), and the second layer is the image layer (i.e. image silver particles embedded in an albumen binder layer). There are several factors threatening the permanence of albumen prints (e.g., fluctuating temperatures and relative humidity, frequent handling, air pollution, light, and improper storage and display). Unlike other paper objects, photographs have special conservation requirements due to their complex and unique nature. A private collection was selected for this study. The collection consists of three albumen prints from Francis Amen's photo collection, which originally belonged to the Elhagar family. Francis Amin is a well-known photo collector in Egypt. The prints date back to 1890. The photographs were characterised and studied by visual inspection, digital microscopy, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDX). Microbiological studies were carried out in the microbiology laboratory at the Faculty of Archaeology at Cairo University. Results revealed that the albumen layer suffers from cracks and chemical degradation, and the secondary supports suffer from both oxidation and hydrolysis. Based on the obtained results, the following conservation procedures were selected and carried out: disinfection, dry cleaning, tear mending and compensating for losses, remounting, retouching, and rehousing. [ABSTRACT FROM AUTHOR]

Purpose: This paper aims to study the suitability of a selection of 3D printing liquid photopolymer resins for their application in the cultural heritage context. Design/methodology/approach: The main concerns regarding the conservation and restoration of cultural assets are the chemical composition and long-term behavior of the new materials that will be in contact with the original object. Because of this, four different LED curing resins were exposed to an accelerated aging procedure and tested to identify the materials which demonstrated a better result. Some specific properties of the material (color, glossiness, pH and volatile organic compound emissions) were measured before and after the exposure. Findings: Some of the properties measured reported good results demonstrating a decent stability against the selected aging conditions. The main changes were produced in the colorimetric aspect, probably indicating other chemical reactions in the material. Likewise, a case study could be also executed to demonstrate the usefulness of these materials in the cultural field. Research limitations/implications: It is necessary to study in more detail the long-lasting behavior of the materials employed with these technologies. Further analysis should be carried out highlighting the chemical composition and degradation process of the materials proposed. Originality/value: This paper contributes to the introduction of curing 3D printing resins in the restoration methodologies of cultural assets. For this, the study of a selection of properties represents the first stage to suggest or reject their use. [ABSTRACT FROM AUTHOR]

Diethyl cyanophosphonate (DCNP), a simulant of Tabun, is a common pollutant in pharmaceutical waste and poses a high risk to living organisms. Herein, we demonstrate a compartmental ligand-derived trinuclear zinc(II) cluster [Zn3(LH)2(CH3COO)2] as a probe for the selective detection and degradation of DCNP. It consists of two pentacoordinated Zn(II) [4.4.3.01,5]tridecane cages bridged through a hexacoordinated Zn(II) acetate unit. The structure of the cluster has been elucidated by spectrometric, spectroscopic, and single-crystal X-ray diffraction studies. The cluster shows a two-fold increased emission as compared to the compartmental ligand (at λexc = 370 nm and λem = 463 nm) due to the chelation-enhanced fluorescence effect and acts as a turn-off signal in the presence of DCNP. It can detect DCNP at nano levels up to 186 nM (LOD). The direct bond formation between DCNP and Zn(II) via the –CN group degrades it to inorganic phosphates. The mechanism of the interaction and degradation is supported by spectrofluorimetric experiments, NMR titration (1H and 31P), time of flight mass spectrometry and density functional theory calculations. The applicability of the probe has been further tested by the bio-imaging of zebrafish larvae, analysis of high-protein food products (meat and fish) and vapour phase detection by paper strips. [ABSTRACT FROM AUTHOR]

This paper presents a process for synthesising iron oxide nanoparticles modified with Cr(II), Cr(III) and Mn(II) ions and immobilised peroxidase. The obtained bionanocatalyst can be successfully applied to biocatalytic hydrogen peroxide decomposition reactions in pollutant removal processes. The iron oxide nanoparticles formed by Fe3O4 with Fe2O3 displayed sizes below 10 nm. The sorption capacities of the material for Cr(II), Cr(III) and Mn(II) ions were 8.81, 5.30, and 5.01 mg g−1, respectively. In the second step, after adsorption of the ions, the materials were subjected to peroxidase immobilisation processes, yielding biocatalysts with hydrogen peroxide degradation activities of, respectively 1.5, 2.1 and 1.4 units per mg. For H2O2 degradation, values of 27.9, 14.8, 20.4 and 0. 2 μg H2O2 per unit POX were achieved for Cr(II)/Fe3O4/Fe2O3/POX, Cr(III)/Fe3O4/Fe2O3/POX, Mn(II)/Fe3O4/Fe2O3/POX and pure peroxidase (POX), respectively, confirming the catalytic efficiency of the carrier-embedded enzyme, demonstrating that the developed method enhances the peroxidase efficiency. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of High Pressure Physics is the property of Chinese Journal of High Pressure Physics Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

2,6-Di-tert-butyl-4-methylphenol (BHT) is an excellent antioxidant that is easily oxidized to 2,6-di-tert-butyl-4-hydroperoxyl-4-methyl-2,5-cyclohexadienone (BHTOOH). For the safety of BHT production and usage, it is meaningful to study the thermal stability and decomposition properties of BHT and BHTOOH. In this paper, the thermal decomposition properties of BHT and BHTOOH were compared by the mini closed pressure vessel test (MCPVT) and differential scanning calorimetry (DSC). Their kinetics of thermal decomposition were studied using thermogravimetric analysis (TGA). The thermal decomposition products of BHT and BHTOOH were analyzed by gas chromatography-mass spectrometry (GC–MS). The results show that there was no significant change in temperature pressure when BHT was warmed up under a nitrogen atmosphere, indicating that BHT was stable within 400 K. The thermal decomposition reaction of BHTOOH was rapid with an initial reaction temperature of 375.2 K. The initial exothermic temperature (Ti) and heat release (QDSC) of DSC were 384.9 K and 865.0 J g−1, respectively. The apparent activation energies (Ea) for the thermal decomposition reactions of BHT and BHTOOH calculated by the Kissinger method were 151.8 kJ mol−1 and 66.07 kJ mol−1, respectively. The main decomposition products of BHT were isobutene and 2-tert-butyl-4-methylphenol. The thermal decomposition products of BHTOOH included BHT, 2,6-di-tert-butyl-4-ethylphenol, 3,5-di-tert-butyl-4-hydroxybenzaldehyde, 4,4′-(1,2-ethanediyl) bis [2,6-bis (1,1-dimethylethyl) phenol, etc. Based on the thermal decomposition behavior and products, the reaction pathway has been described. These results indicate that BHT is a potential thermal hazard during production, storage and application. For the safety of the chemical industry, the oxidation of BHT should be avoided. [ABSTRACT FROM AUTHOR]

The extensive use of carbon fiber-reinforced plastics (CFRP) in aerospace, civil engineering, and other fields has resulted in a significant amount of waste, leading to serious environmental issues. Finding appropriate methods for recycling CFRP waste and effectively reusing recycled carbon fibers (rCFs) has become a challenging task. This paper presents an overview of the current status of CFRP waste and provides a systematic review and analysis of recycling technologies. In addition to discussing mechanical recycling, thermal decomposition, and chemical solvent degradation methods, the organic alkali/organic solvent method for recycling resins is also elucidated. By introducing the recycling conditions and outcomes of the organic alkali/organic solvent method, the study highlights its significance as a reference for carbon fiber recycling. Furthermore, the paper reviews the current state of rCFs utilization based on its application domains, focusing on research advancements in fiber composites and cementitious composites. Based on these findings, the paper summarizes the existing research limitations and identifies specific areas that require further attention in recycling techniques and rCFs utilization. Lastly, this review provides a prospect on the future of recycling and reusing CFRP waste. [ABSTRACT FROM AUTHOR]

This paper is part II of the review on metabolism and chemical degradation of new antidiabetic drugs from glutides, gliflozins and gliptins. It is well known that metabolism data can be helpful for deriving safe levels of degradation impurities and their qualifying as far as toxicological aspects are concerned. As a result, it could link the quality of respective pharmaceutical products to clinical practice and patients. Some overlapping pathways of transformations of these important drugs of different chemical structures and different mechanisms of action were discussed. At the same time, the paper summarized interesting analytical tools for conducting modern drug metabolism as well as drug degradation experiments. The methods described here include liquid chromatography (LC) and liquid chromatography coupled with mass spectrometry (LC-MS or LC-MS/MS), which are widely used for detection and quantitative measurements of the drugs, their metabolites and degradants, as well as radiometric methods that are suitable for pharmacokinetic experiments. Special attention was paid to dedicated types of packing in chromatographic columns, as well as to special solutions in the LC-MS procedures. The present part addresses the analytical approaches elaborated for examining the metabolism and degradation pathways of gliptins that are dipeptidyl peptidase 4 (DPP-4) inhibitors. [ABSTRACT FROM AUTHOR]

The decompositions of soft sets and soft matrices are important tools for theoretical and practical studies. In this paper, firstly, we study the decomposition of soft sets in detail. Later, we introduce the concepts of α-upper, α-lower, α-intersection and α-union for soft matrices and present some decomposition theorems. Some of these operations are set-restricted types of existing operations of soft sets/matrices, others are α-oriented operations that provide functionality in some cases. Moreover, some relations of decompositions of soft sets and soft matrices are investigated and the newfound relations are supported with numerical examples. Finally, two new group decision making algorithms based on soft sets/matrices are constructed, and then their efficiency and practicality are demonstrated by dealing with real life problems and comparison analysis. By using these proposed approaches, solutions can be presented to soft set-based multi-criteria decision making problems, both ordinary and involving primary assessments. These allow to handle soft set-based multi-criteria decision making from diffierent perspectives. [ABSTRACT FROM AUTHOR]

In this paper, a 3D transient multi-physical field model is developed to capture the complex processes inside a fused magnesia furnace. The multi-physics model integrates electromagnetism, thermodynamics, decomposition reactions, and flow. The three-phase submerged magnesia furnace includes an arc, magnesite ores, a melting pool, and a solidification ingot. For a more comprehensive analysis of the optimal design of industrial operations, the influence of the key index of electrode insertion depth on temperature and reaction is also discussed. The results show that the current density in the fused magnesia furnace is almost the same as the joule heat distribution, and there is an obvious area of low energy density affected by the skin effect, which leads to the waste of electric energy. The temperature at the center of the arc reaches 12,000 K, and the plasma areas formed at the end of the three electrodes are connected to each other to form a closed current path, which provides energy for the process of melting magnesia. The arc region is an ellipsoid with a length of ~30 mm and a diameter of ~49 mm. The decomposition reaction of magnesite mainly occurs in the arc area, and the radiation heat provided by the high-temperature arc is used as the heat source. There is almost no magnesite in the molten pool, and the molten pool only provides energy for the melting process of magnesia. When the electrode insertion depth is 0.4, 0.5, 0.6, and 0.7 m, the arc length is 0.049 m, 0.066 m, 0.068 m, and 0.059 m, respectively. According to the simulation results, there is an optimal electrode insertion depth. [ABSTRACT FROM AUTHOR]

In gas-insulated equipment, the decomposition of SF6 is closely related to the residual traces of O2 and H2O in the equipment. However, the decomposition mechanism has not yet been clarified. In this paper, the adsorption and defluorination of SF6 on the preadsorbed Cu(111) surface were calculated based on density flooding theory and transition state theory. Besides, the influence mechanism of O atoms and H2O molecules on the defluorination process is analyzed by comparing the energy barrier, reaction heat, and density of states. The results show that pre-adsorption of O atoms changes the adsorption sites of SFx, but has no significant effect on the adsorption energy. In addition, the O atom has a certain inhibitory effect on the decomposition process, and SF → S + F is the key to determining the reaction rate. In contrast, H2O will not only promote the adsorption of SFx to the surface but also reduce the total reaction heat of the decomposition reaction by 135.37 kcal·mol−1, driving the decomposition process of SF6. In this paper, stable co-adsorption configurations of low-fluorosulfide and co-adsorption groups were determined, and the effects of O and H2O preadsorption on SF6/Cu gas–solid interactions were initially revealed. [ABSTRACT FROM AUTHOR]

In Dechen (Bde chen) County, Yunnan Province, a Tibetan county of the People's Republic of China, prominent lay Buddhist practitioners work to resist and mitigate the impacts of agrochemical pollution and climate change on sacred landscapes. In this region of northwest Yunnan officially renamed and dubbed "Shangri-La" by the local and national state for tourism purposes, and in alignment of this name with the term Shambala, a place of divine serenity in Tibetan Buddhism, the protagonists in this paper insist that chemical futures and pollution are only adding to the creation of a "fake" Shangri-La, and that more than human- and nature-centric views are necessary in building a more ecologically sound future. This paper ethnographically analyses these activities and motivations in the context of ecocentric views surrounding indigenous Tibetan more-than-human spirit worlds. I ask what drives rural Tibetan grape-growers to pursue an ecologically friendly agenda. Motivations include observation of chemical degradation on land, Buddhist ethics, local land worship, and conceptions that being a local Tibetan should revolve around the preservation of sacred landscapes and mountain gods and spirits rather than purely economic profit and development. A critical variable, however, is that lay Buddhists holding these beliefs are exceptions, with most villages showing more concern for the economic benefits of new cash agricultures over sacred landscapes and spirits. I argue that while many villagers are willing to ignore the long-term vitality of the sacred landscape in favour of economic prosperity and view new economic activities as morally acceptable within Tibetan spirituality, some individuals insist that preserving the local landscape is paramount to a sustainable future both locally and across Greater China. [ABSTRACT FROM AUTHOR]

This paper evaluates the durability of geotextiles exposed to accumulated weathering and liquid factors. Polypropylene and polyester/polyamide woven geotextiles (GTXw) were applied in this study. Weathering tests were performed in a chamber (UVA lamps), and the geotextiles were immersed in acidic and alkaline liquids to evaluate their chemical degradation. Thermogravimetric Analysis (TGA) and Infrared (IR) spectroscopy were carried out to understand the photodegradation results. In the analysis of the accumulation of degradation factors, tensile strength-strain losses were verified under all conditions considered. The polyester/polyamide geotextile presented a tensile strength loss of 77.2% in the weathering test (first stage) and in acidic liquid (second stage). In the alkaline liquid (second stage), the loss was 43.9%. The degradation conditions depended on the geotextiles' structures and polymeric compositions. The application of the partial Reduction Factors (RFP) closest to the project requirements is essential to the reliability of different geotechnical and civil applications to mitigate environmental impacts. [ABSTRACT FROM AUTHOR]

Proton exchange membrane fuel cells (PEMFCs) have been recognized as a promising power generation source for a wide range of automotive, stationary, and portable electronic applications. However, the durability of PEMFCs remains as one of the key barriers to their wide commercialization. The membrane electrode assembly (MEA) as a central part of a PEMFC, which consists of a proton exchange membrane with a catalyst layer (CL) and gas diffusion layer (GDL) on each side, is subject to failure and degradation in long-running and cycling load conditions. The real-time monitoring of the degradation evolution process through experimental techniques is challenging. Therefore, different numerical modeling approaches were proposed in the literature to assist the understanding of the degradation mechanisms in PEMFCs. To provide modeling progress in the addressed field, this paper briefly discusses the different degradation mechanisms occurring in the MEA. In particular, we present a detailed review of MEA degradation modeling research work, with special attention paid to the physical-based models (mechanistic models). Following the most recent relevant literature, the results showed that the combination of microstructure component models with macro-scale comprehensive PEMFC models provides a better understanding of degradation mechanisms when compared to single-scale degradation models. In this sense, it is concluded that in order to develop an accurate and efficient predictive degradation model, the different relevant scales ranging from nano- to macro-sized scales should be considered, and coupling techniques for multiscale modeling have to be advanced. Finally, the paper summarizes the degradation models for different MEA components. It is highlighted that the GDL chemical degradation models that describe damage accumulation are relatively limited. The paper provides a useful reference for the recent developments in the MEA degradation modeling of PEMFCs. [ABSTRACT FROM AUTHOR]

Due to its excellent insulation properties and environmental characteristics, C6F12O gas mixture shows a wide range of applications prospects in low and medium voltage gas insulated equipment. The thermal decomposition characteristics of gas insulating medium are of great importance for the industrial application of gases and the operation and maintenance of equipment. In this paper, the type and concentration of the main products of the thermal decomposition of C6F12O/O2/CO2 gas mixture are researched experimentally with different O2 mixing ratios, and the effective gas production rate is analyzed. The mechanism of thermal decomposition of C6F12O/O2/CO2 gas mixture is studied based on ReaxFF molecular dynamics. The experimental results show that the main thermal decomposition products are CF4, C2F6, C3F6, C3F8, C4F10, C5F12, and C6F14. The addition of O2 promotes the thermal decomposition of the C6F12O/O2/CO2 gas mixture. Theoretical studies show that the C6F12O in the mixture undergoes the multistage decomposition reaction. The main particles of all levels of decomposition are C3F7COCF2, CF3, CF3CFC(O) (CF2), CF2CO, C3F7, C3F7C(O) (CF2), CFC(O) (CF2), FCCO, F, CF3CFCF2, CO, and CF2. The results of the research can provide some reference for the engineering application and maintenance of C6F12O gas mixture insulated equipment. [ABSTRACT FROM AUTHOR]

Chemical looping ammonia generation is a promising, efficient, and environmentally friendly synthesis of ammonia by cycling N-absorption and N-desorption reactions. A portion of the generated NH 3 decomposes at the reaction temperature of the N-desorption reaction. In order to promote the N-desorption reaction and inhibit the decomposition of NH 3 , the effect of α-Al 2 O 3 loading on the N-desorption reaction was investigated in this paper by fixed-bed experiments. The mechanism was revealed using Density functional theory (DFT) calculations. The results showed that when the reaction temperature increased, the conversion of AlN and the yield of NH 3 increased, but the actual NH 3 conversion decreased. When the steam concentration increased, the conversion of AlN, the yield of NH 3, and the actual NH 3 conversion increased. The loading of α-Al 2 O 3 could facilitate the N-desorption reaction and inhibit the decomposition of NH 3. The 40 wt% α-Al 2 O 3 had the highest conversion of AlN. The 80 wt% α-Al 2 O 3 had the highest yield of NH 3. The actual efficiency of ammonia production at 1075 °C with 80 wt% load increased from 45.5% without load to 58.5%. The DFT calculations revealed the mechanism: α-Al 2 O 3 surface promotes the dissociation of H 2 O molecules to make more hydroxyl groups in the reaction system, which promotes the transfer of H+ and the N-desorption reaction. Meanwhile, the adsorption of NH 3 by the α-Al 2 O 3 surface protected NH 3 and inhibited its decomposition. [Display omitted] • The loading of α-Al 2 O 3 could promote the N-desorption reaction and inhibit the decomposition of NH 3. • The inhibition of NH 3 decomposition by α-Al 2 O 3 increased with increasing reaction temperature. • α-Al 2 O 3 promotes H 2 O dissociation and NH 3 adsorption thereby increasing the actual yield of NH 3. [ABSTRACT FROM AUTHOR]

Perovskite solar cells have made significant progress in the past decade, demonstrating promising potential for next‐generation solar technology. However, the strain‐induced intrinsic instability of mixed‐halide perovskites poses a significant obstacle to their widespread commercialization. Relaxation of the perovskite lattice strain is a crucial approach for enhancing photovoltaic performance and broadening their application potential. In this study, the authors conduct an analysis of strain progression in perovskite thin films, examining its impact on the physical properties of perovskites and the performance of perovskite solar cells. Furthermore, they explore its influence on device stability from the perspectives of phase transitions, chemical decomposition, and mechanical fragility. Additionally, they provide a summary of key advancements in strain‐relaxation strategies and offer design principles and synthetic approaches to address the issue of lattice strain in perovskites. This paper is intended to lay the groundwork for the theoretical development of effective strain‐relaxation methods, moving beyond sole reliance on empirical optimization. [ABSTRACT FROM AUTHOR]

Featured Application: Development of intelligent and real-time monitoring systems for transformer health diagnostics and condition monitoring. Power transformers, like other High-Voltage (HV) electrical equipment, experience aging and insulation degradation due to chemical, mechanical and electrical forces during their operation. Partial discharges (PD) are among the most predominant insulation breakdown mechanisms. Monitoring partial discharges has proven to provide valuable information on the state of the insulation systems of power transformer, allowing transformer operators to make calculated decisions for maintenance, major interventions and plan for replacement. This systematic literature review aims to systematically examine the use of machine learning techniques in classifying PD in transformers to present a complete indicator of the available literature as well as potential literature gaps which will allow for future research in the field. The systematic review surveyed a total of 81 research literatures published from 2010 to 2023 that fulfilled a specific methodology which was developed as part of this study. The results revealed that supervised learning has been the most widely used Artificial Intelligence (AI) algorithm, primarily in the form of Support Vector Machine (SVM). The collected research indicated 20 countries represented in the publications, with China carrying out 32% of the research, followed by India with 10%. Regarding PD, the survey revealed that most researchers tend to investigate numerous types of PD and compare them to one another. Furthermore, the use of artificial PD defect models to simulate the occurrence of PD is widely used versus the use of actual power transformers. Most of the literature tends to not specify the physical characteristics of PD, such as the magnitude of PD, PD inception voltage and PD extinction voltage. [ABSTRACT FROM AUTHOR]

The YK 1 shipwreck, found at Yenikapı, Istanbul, is one of 37 shipwrecks dating to the medieval era. This paper describes the studies and the processes which were conducted to conserve the YK 1. Firstly, the level of physical and chemical degradation of the wood from the YK 1 was examined, which revealed that the wood was highly degraded. Therefore, PEG 2000 was chosen for the impregnation process before vacuum freeze-drying. In addition, the ASE values confirmed that the PEG 2000 impregnation and vacuum freeze-drying method together were successful in conserving the YK 1, with values higher than PEG 2000 impregnation and vacuum freeze-drying methods alone. The concentration of the PEG solution in the tank was monitored throughout the impregnation process. Following this, samples taken from the wood cores were analysed using FTIR to evaluate the effectiveness of the impregnation process. Finally, SEM was used to examine the effectiveness of the PEG 2000 impregnation and vacuum freeze-drying method. The SEM images showed that the PEG 2000 was uniformly distributed, and the wood had no deformation after freeze-drying. [ABSTRACT FROM AUTHOR]

Aim. Compressed air vessels are responsible for injecting compressed air to the mechanical flying device. It should be noted that the pressure level inside these vessels is very important in conducting all operational stages successfully; therefore, it is of high significance to be assured of the quality of the vessels being used. This study was done in 2017 in order to calculate and estimate the reliability of compressed air vessels in mechanical flying device system with proposing a potential failures assessment and accelerated test approach taking into consideration the current methods. Methods. The paper uses methods of Fault Tree Analysis, Failure Mode & Effect Analysis and Accelerator tests. Initially, the interactions among the components were identified using the Design Structure Matrix in order to design a matrix to help estimate the reliability; consequently, improve equipment performance. Next, failures root recognition was done using Fault Tree Analysis diagram, then, failures reasons prioritization was done using Failure Mode & Effects Analysis tables. Accelerator tests were designed and applied on failure mechanisms such as leakage by pressure on vessels, corrosions on steal head, nipples, O-ring creeping, O-ring ozone cracking and liner chemical degradation. After that, the average of failure rates was calculated within the taking after stage for each test. Within the conclusion, the result of failure rates from the accelerator tests was compared with the result of failure rates from the process approach. Consequently, the most elevated amount of these two approaches was defined as the total failure rate; product reliability and lifetime were calculated utilizing this amount. Results. The following finding were obtained using the proposed methods. When Windy Liner was used, vessel lifetime was six years and half and vessel reliability in ten years was 0/22. Whereas, when Rotational Liner was used, vessel lifetime was eight years and three months and vessel reliability in ten years was 0/3. Conclusion. The approach proposed in the paper allows accelerator degradation test can also be used instead of accelerated test in order to calculate the reliability of failure mechanisms. In the event that high-quality and legitimate O-rings are used, vessel reliability and lifetime can be increased. [ABSTRACT FROM AUTHOR]

The purpose of this paper is the investigation of the catalytic effect of graphene oxide–copper oxide nanocomposite (GCNC) on the thermal comportment and decomposition reaction kinetics of a double‐base propellant (DBP) formulation. Differential scanning calorimetry (DSC) was used to conduct the thermal analysis. Using well‐known iso‐conversional kinetics methods, namely, Vyazovkin's nonlinear integral with compensatory effect (VYA/CE), Kissinger–Akahira–Sunose (KAS), and Flynn–Wall–Ozawa (FWO), the thermokinetic parameters for the investigated propellant, including activation energy and frequency factor, were estimated. Additionally, based on the results obtained from the kinetic analysis, the critical ignition temperature was calculated. The results showed that after the addition of GCNC, the activation energy barrier is lowered by 18%, and the critical ignition temperature is reduced. [ABSTRACT FROM AUTHOR]

Carbon is often used as a reactant to realize the conversion of CO2 in metallurgy, but it additionally increases carbon emissions. This paper studies the reaction process and decomposition rate of CO2 in molten iron. It is found that the decomposition rate of CO2 is 84.35 pct in oxygen-saturated molten iron. At the same time, aiming at the reduction of deoxidized product FeO, a direct-current electrolysis method of steel–slag is proposed, which can realize the carbon-free deoxidization of CO2 to produce CO. [ABSTRACT FROM AUTHOR]

The preparation of ammine complexes of transition metals having oxidizing anions such as permanganate and perrhenate ions is a great challenge due to possible reactions between ammonia and oxidizing anions during the synthesis of these materials. However, it has an important role in both the development of new oxidants in organic chemistry and especially in the preparation of mixed-metal oxide catalyst precursors and metal alloys for their controlled temperature decomposition reactions. Therefore, in this paper, synthetic procedures to prepare ammonia complexes of transition metal permanganate, pertechnetate, and perrhenate (the VIIB group tetraoxometallates) salts have been comprehensively reviewed. The available data about these compounds' structures and spectroscopic properties, including the presence of hydrogen bonds that act as redox reaction centers during thermal decomposition, are given and evaluated in detail. The nature of the thermal decomposition products has also been summarized. The available information about the role of the ammine complexes of transition metal permanganate salts in organic oxidation reactions, such as the oxidation of benzyl alcohols and regeneration of oxo-compounds from oximes and phenylhydrazones, including the kinetics of these processes, has also been collected. Their physical and chemical properties, including the thermal decomposition characteristics of known diammine (Ag(I), Cd, Zn, Cu(II), Ni(II)), triammine (Ag(I)), and simple or mixed ligand tetraammine (Cu(II), Zn, Cd, Ni(II), Co(II), Pt(II), Pd(II), Co(III)), Ru(III), pentaammine (Co(III), Cr(III), Rh(III) and Ir(III)), and hexaammine (Ni(II), Co(III), Cr(III)) complexes of transition metals with tetraoxometallate(VII) anions (M = Mn, Tc and Re), have been summarized. The preparation and properties of some special mixed ligand/anion/cation-containing complexes, such as [Ru(NH3)4(NO)(H2O)](ReO4)2, [Co(NH3)5(H2O)](ReO4)2, [Co(NH3)5X](MnO4)2 (X = Cl, Br), [Co(NH3)6]Cl2(MnO4), [Co(NH3)5ReO4]X2 (X = Cl, NO3, ClO4, ReO4), and K[Co(NH3)6]Cl2(MnO4)2, are also included. [ABSTRACT FROM AUTHOR]

Featured Application: This research paper promotes green engineering in slope stabilization. The results of this study can serve as a reference in understanding the strength performance of natural fiber geotextile, specifically coir geotextile, as an alternative material for slope stabilization. Slope stability is one of the crucial factors to consider in every civil engineering project. One widely used method to stabilize slope is the use of polymeric products called geosynthetics. Natural fiber geosynthetics used for geotechnical applications have attracted attention because of their environmental and economic benefits. Coir fibers made into nonwoven geotextiles are utilized in this study as an alternative material for slope stabilization. One drawback of coir fiber geotextiles is their low tensile strength and limited life span due to their susceptibility to environmental factors. This study was conducted to evaluate the effect of mercerization and bleaching treatment on the strength performance of nonwoven coir geotextiles after exposure to conditions simulating biological and chemical degradation. Microscopic images of treated coir geotextiles show the removal of surface impurities that altered the physical components in the fiber. The grab tensile strength results prove that the mercerized coir geotextiles are suitable for field conditions and groundwater exposure. The untreated coir geotextiles showed superior puncture resistance relative to the chemically treated geotextiles. The chemical treatments improved the tensile strength; however, they weakened the puncture resistance of the coir geotextile due to the decrease in thickness. A slope stability simulation conducted using Rocscience Slide2 version 9.017 software proved that coir geotextiles can effectively reinforce slopes, with strength performance almost comparable to that of synthetic geotextiles. [ABSTRACT FROM AUTHOR]

The paper presents an example of regeneration of a common rail piezoelectric fuel injector, which was carried out with using used parts. The most important stages of maintenance activities are listed, as well as the types of diagnostic tests performed on separate test benches. The obtained results indicate that this process can be effectively carried out with existing technological problems and lack of support from the manufacturer. At the same time, it was shown that, contrary to popular belief, cannibalisation does not have to be limited only to minor elements, but also to key components important from the point of view of the satisfactory technical condition and correct working of the fuel injector during further operation. [ABSTRACT FROM AUTHOR]

Two new allelochemicals (A) m.f. C35H44O23, m.p. 231-234oC [M+] 832 and (B) m.f. C33H40O21, m.p. 244-2460C, [M+] 772 have been isolated from ethanolic extract of the roots of plant Lagascea mollis Cav. along with two known compounds luteolin 7-O-β-D-glucopyranoside (C) and Isorhamentin (D). The structure of the two new allelochemicals have been characterised as 5,7,3'-trihydroxy-3,6,4'-trimethoxy flavone-5-O-β-D-glucopranosyl-7-O-α-L-rhamnopyranosyl(1→4)-O-α-L-arabinopyranoside (A) and 5, 7,3'5'-tetrahydroxy-3-methoxy flavone-7-O-β-D-galactopyranosyl-(1→4)-O-β-D-xylopyranosyl-5'-O-α-L-rahmnopyranoside (B) by various chemical degradations, colour reactions and spectral analysis. In this paper, the two new compounds A and B were screened against various bacteria and fungi and showed good results. Antioxidant activity of the two compounds A and B was evaluated by DPPH radical scavenging method. The result showed that both the compounds may be used as antioxidants agents. [ABSTRACT FROM AUTHOR]

Copyright of Materials & Technologies / Materiali in Tehnologije is the property of Institute of Metals & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Given the enormous safety risks and environmental pollution that restrict the green development of isocyanate produced by phosgene reactions, we propose a new green and intrinsically safe route for synthesizing diisocyanates containing the furan ring from 5-hydroxymethylfurfural. In this work, the following novel reactions have been systematically investigated, including synthesizing a new compound methyl furan-2,5-dimethylene dicarbamate (FDC) using 2,5-bis(aminomethyl)furan (BAF) and dimethyl carbonate (DMC), the selective hydrogenation of FDC to a new compound methyl tetrahydrofuran-2,5-dimethylene dicarbamate (THFDC), and FDC and THFDC catalytic decomposition to produce corresponding furan-2,5-dimethylene diisocyanate (FDI) and tetrahydrofuran-2,5-dimethylene diisocyanate (THFDI). The results showed that CH3ONa could effectively catalyze the synthesis of FDC from BAF and DMC, and the separation yield of FDC was 98.1% under mild conditions including a nBAF : nDMC ratio of 1 : 10 at 70 °C for 4 h. CH3ONa can be recycled up to four times with high stability. A 0.5% Pd/γ-Al2O3 catalyst with low Pd loading was prepared, and it showed high catalytic activity and stability for FDC hydrogenation to THFDC, with a THFDC yield of 99.9% at 100 °C, 2 MPa H2 and 1 h, and the catalyst could be reused after simple treatment with ethanol. The structure–activity relationship of supported Pd catalysts was studied. The conditions for the thermal decomposition reactions of FDC and THFDC were optimized, resulting in FDI and THFDI yields as high as 89.6% and 92.8%, respectively. Owing to the urgent need for raw materials sustainability and environmental friendliness, the brand-new safe pathway for synthesizing FDI and THFDI was constructed, significantly improving the competitiveness of the non-phosgene method in preparing bio-based isocyanate. [ABSTRACT FROM AUTHOR]

Asymmetric organocatalysis has been recognized as one of the "top 10 emerging technologies" in chemistry by IUPAC in 2019. Its potential to make chemical processes more sustainable is promising, but there are still challenges that need to be addressed. Developing new and reliable enantioselective processes for reproducing batch reactions on a large scale requires a combination of chemical and technical solutions. In this manuscript, we combine a robust immobilized chiral phosphoric acid with a new packed-bed reactor design. This combination allows scaling up of the enantioselective addition of thiols to imines from a few milligrams to a multi-decagram scale in a continuous flow process without physical or chemical degradation of the catalyst. [ABSTRACT FROM AUTHOR]

In this paper, a low-content Ce-doped trimetallic sulfide catalyst (Ce–NiFe2S4) was prepared by the hydrothermal method. The prepared catalyst can improve the oxidant potential of peroxymonosulfate (PMS) to degrade rhodamine B (RhB) dye efficiently in a low dosage. In addition, Ce–NiFe2S4 possessed a magnetic property due to the contained nickel-iron elements. Therefore, the catalyst material has good separation and reusability characteristics. The factors influencing the degradation efficiency of rhodamine by a Ce–NiFe2S4-facilitated PMS oxidation system, such as initial solution pH, PMS dosage, catalyst dosage, and temperature were investigated. The results revealed that RhB can be degraded by 95 % in 30 min at the optimal conditions (100 mg/L catalyst, 200 mg/L PMS). The reaction rate would be further increased when the initial solution pH was 3 with the reaction temperature at 50°C. Furthermore, the quenching experiments verified that 1O2 made an important contribution to the degradation of pollutants as a main active species. SO4•– and •OH, to some extent, participated in the chemical degradation reaction. S2– promoted cycling of redox reactions between metal ions and PMS to ensure catalyst stability and reusability. [ABSTRACT FROM AUTHOR]

For decades, it has been known that the creation of oxygenated functional groups, especially carbonyl and sulfoxide, is among the main causes of chemical aging and degradation of asphalt. However, is the oxidation of a bitumen homogeneous? The focus of this paper was to follow the oxidation phenomena through an asphalt puck during a pressure aging vessel (PAV) test. According to the literature, the asphalt oxidation process that leads to the creation of oxygenated functions can be divided into the following successive main steps: the absorption of oxygen in asphalt at the air/asphalt interface, diffusion into the matrix, and reaction with asphalt molecules. To study the PAV oxidation process, the creation of carbonyl and sulfoxide functional groups in three asphalts were investigated after various aging protocols by Fourier transform infrared spectroscopy (FTIR). From these experiments performed on different layers of asphalt puck, it was observed that PAV aging resulted in a nonhomogeneous oxidation level inside the entire matrix. Compared to the upper surface, the lower section exhibited carbonyl and sulfoxide indices 70% and 33% lower, respectively. Moreover, the difference in the oxidation level between the top and bottom surfaces increased when the thickness and viscosity of the asphalt sample increased. [ABSTRACT FROM AUTHOR]

Polyurethane resins are often used in the geotechnical domain to fill fine fissures, small underground cavities, or soil pores to reduce soil permeability, improve the bearing capacity of a shallow foundation, limit the compressibility of the foundation soil, reinforce road embankments, or obtain a lifting effect of structures that have suffered differential settlements. Polyurethane resins have been widely investigated from the mechanical point of view, but the effect of long-term aging on mechanical behavior is not yet well documented. This paper aims to investigate mechanical, physical, and chemical variations following an artificial aging treatment of polyurethane resin specimens with different densities, obtained under different expansion conditions. Artificial aging was obtained in several ways, such as soaking samples in different chemical solutions or subjecting them to different environmental conditions, to simulate the long-term effect of staying in the underground environment. Besides verifying the volume stability of specimens before and after aging, uniaxial compression tests have been performed on samples with and without aging treatment to verify maintenance or any change in the mechanical properties. Accelerated aging does not seem to affect volume change or mechanical behavior of the tested polyurethane resins. Comparison of both physical and mechanical properties before and after aging allows the deduction of useful information for practical geotechnical applications. The tested polyurethane resins showed (1) very high durability under several wetting-drying cycles, (2) high stability if exposed to aggressive chemical agents, and (3) practically unchanged deformability and strength in conditions very similar to those present in the ground. Moreover, the samples that underwent the highest volume change when soaked in chemical solutions revealed no any chemical degradation under infrared spectroscopy. [ABSTRACT FROM AUTHOR]

Cold spraying is an attractive solid-state processing technique in which micron-sized solid particles are accelerated towards a substrate at high velocities and relatively low temperatures to produce a coating through deformation and bonding mechanisms. Metal, ceramic, and polymer powders can be deposited to form functional coatings via cold spraying. MAX phase coatings deposited via cold spraying exhibit several advantages over thermal spraying, avoiding tensile residual stresses, oxidation, undesirable chemical reactions and phase decomposition. This paper presents a review of recent progress on the cold-sprayed MAX phase coatings. Factors influencing the formation of coatings are summarized and discussions on the corresponding bonding mechanisms are provided. Current limitations and future investigations in cold-sprayed MAX coatings are also listed to facilitate the industrial application of MAX phase coatings. [ABSTRACT FROM AUTHOR]

This paper presents a novel family of jarosites with the molecular formula MFe3(SO4)2(OH)6·xH2O; M = Na, K, NH4 that have high efficiency in the adsorption of As(V) and Pb(II) dissolved in water. The jarosites have been prepared by conventional heating at temperatures close to 95 °C for 3 h. The synthesis method was improved and optimized to reduce the time and energy consumption. The improved conventional heating method allowed for the synthesis of Na− and K−jarosites with a yield of up to 97.8 wt.% at 105 and 150 °C, respectively, in 3 h. The Na−, K−, and NH4−jarosites were synthesized at 150 °C in 5 min via a microwave-assisted method, which yielded jarosite crystalline agglomerates with more uniform topography, shape, and size than the conventional method. Both methods allowed the selective synthesis of jarosites. Chemical decomposition of jarosites suspended in water occurred at a pH less than 2 and higher than 10 and temperatures up to 150 °C. In the solid state, the jarosites were thermally stable at least to 300 °C. The Na−jarosite presented a maximum adsorption capacity (Qmax) of 65.6 mg g−1 for As(V) and 94 mg g−1 for Pb(II). The jarosites are considered promising bifunctional adsorbents for the remediation of contaminated water due to their improved synthesis method, stability, and high adsorption capacity for ions of different natures. [ABSTRACT FROM AUTHOR]

In recent years, the rapid development of the new energy vehicle industry has led to an increase in the production of used lithium-ion batteries. The recycling of waste lithium-ion batteries is expected to alleviate the shortage of valuable metals in battery materials. The electrode material is adhered to the collector by a viscous organic binder such as PVDF. A key step in recycling is to separate the anode material and aluminum foil from the waste lithium batteries to obtain materials rich in valuable metals. Compared with chemical dissolution and decomposition, pyrolysis pretreatment is a simple and feasible method. By reducing the binding force between the binder and the positive active substance at a high temperature, organic matter can be eliminated by thermal decomposition at a high temperature. At the same time, the organic component of PVDF has a high calorific value, and the energy can be recycled and reused, which can save energy. The pyrolysis process and pyrolysis behavior of spent LIBs materials were studied in this paper. FWO, Friedman and KAS conversion methods were spent to compare the pyrolysis kinetics of positive electrode materials. Thermogravimetric analysis shows that the cathode material is decomposed into three stages with mass losses of 1.7%, 1.2% and 3.3%, respectively. The activation energy (Eα) calculated by the three model-free methods is best fitted by the FWO method. During the pyrolysis process, the concentration of F decreases gradually with the increase in temperature, and the concentrations of Ni, Mn, Co and Li remain stable. Most of the harmful element (F) in spent LIBs is converted into HF gas, which can be adsorbed by alkaline solution. The analysis of pyrolysis kinetics and pyrolysis products is of great significance for large-scale pretreatment of spent lithium-ion batteries. [ABSTRACT FROM AUTHOR]

In this study, we investigated the efficiency of photocatalytic degradation and chemical oxygen demand (COD) reduction from woodchips industry wastewater using α-Fe2O3@TiO2@SO3H. A magnetic α-Fe2O3@TiO2@SO3H was prepared as a heterogeneous photo-Fenton catalyst. The Fourier transform infrared (FT-IR), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray (EDX), and elemental mapping (MAP) analyses were performed to determine the structure and morphology of synthesized photocatalysts. The response surface methodology (RSM) was used to optimize the photo-Fenton process based on a Box-Behnken design (BBD). The parameters such as catalyst dosage, H2O2 dosage, pH, and contact time on photocatalytic degradation and the reduction of COD were studied. The maximum photocatalytic degradation of 93.75% and COD reduction of 86.54% were achieved at a dosage of the catalyst of 1 g L−1, H2O2 dosage of 40 mg L−1, and a pH of 3.5 at 45 min. The kinetics of the photo-Fenton process was studied for the woodchips wastewater treatment under optimum conditions. The pseudo-second-order kinetic model for photocatalytic degradation and COD reduction was obtained. The results indicated that a α-Fe2O3@TiO2@SO3H could be used as an effective heterogeneous photocatalyst for the treatment of woodchips industry wastewater. [ABSTRACT FROM AUTHOR]

In this paper, we distinguished the degradation of alkali-activated material (AAM) exposed to sulfuric acid as physical (scaling, spalling, cracking, breaking, etc.) and chemical degradation (neutralization), because the mechanisms of these two types of degradation are different. Then, the effects of curing method, raw materials, and their mixing proportions on the two kinds of degradation of AAMs containing GGBFS were investigated in detail, including liquid-filler ratio, component of alkali activator, chemical admixture, inactive filler alternative to fly ash (FA), addition of municipal waste incineration bottom ash (BA), etc. The experimental results show that (a) small liquid-filler ratio, heat-curing, and the use of blended alkali activator solution of sodium silicate and NaOH can reduce both physical and chemical degradation of AAMs; (b) large GGBFS content or AE agent addition decreases the physical degradation, but increases the chemical degradation; (c) using crushed stone powder to replace FA and adding BA or a retarder would increase the physical and chemical degradation; but (d) the use of drying shrinkage reducer composed of polyether derivatives does not affect acid resistance. We also discussed the applicability and limitation of XRD and SEM-EDS in analyzing the chemical compositions of Ca-rich AAMs exposed to sulfuric acid, and found that (e) XRD analysis can identify the gypsum formation, and the gypsum peak intensity is related to the physical degradation of the Ca-rich AAMs; (f) by SEM-EDS analysis, the decalcification and dealkalization of C-A-S-H gels can be judged from the decrease in the average Ca/Si atomic ratio and the average Na atomic percentage in the acid corrosion area, but dealumination can be only determined from the dissimilarity of Al and Si elemental maps; and (g) if the CaO/SO3 molar ratio ranges from 0.8 to 1.0, gypsum formation can be estimated. [ABSTRACT FROM AUTHOR]

This paper reports the degradation of the sulfadiazine (SDZ) drug with a hybrid advanced oxidation process (AOP) of heterogeneous α-Fe2O3/persulfate coupled with hydrodynamic cavitation. The major objectives of the study are parametric optimization of the process and elucidation of the chemical mechanism of degradation. The optimum conditions for maximum SDZ degradation of 93.07 ± 1.67% were as follows: initial SDZ concentration = 20 ppm, pH = 4, α-Fe2O3 = 181.82 mg/L, Na2S2O8 = 348.49 mg/L, H2O2 = 0.95 mL/L, inlet pressure = 0.81 MPa (8 atm), orifice plate configuration: hole dia. = 2 mm and number of holes = 4. Density functional theory (DFT) calculations revealed that the atoms of SDZ with a high Fukui index (f0) were potentially active sites for the attack of •OH and SO 4 · - radicals. Fukui index calculation revealed that atom 11 N has a higher value of f0 (0.1026) for oxidation at the α-amine group of the sulfadiazine molecule. Degradation intermediates detected through LC–MS/MS analysis corroborated the results of DFT simulations. Using these results, a chemical pathway has been proposed for SDZ degradation. [ABSTRACT FROM AUTHOR]

Copyright of Clean Coal Technology is the property of Clean Coal Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Ammonium dinitramide (ADN) is considered as a potential substitute for ammonium perchlorate in energetic materials due to its high density, positive oxygen balance, and halogen-free characteristics. However, its application has been severely limited because of its strong hygroscopicity, difficult storage, and incompatibility with isocyanate curing agents. In order to better bloom the advantages of the highly energetic and environment-friendly ADN in the fields of energetic materials, an in-depth analysis of the current situation and discussion of key research points are particularly important. In this paper, a detailed overview on the synthesis, thermal decomposition, hygroscopic mechanism, and anti-hygroscopicity of ADN has been discussed, its application in powdes and explosives are also presented, and its future research directions are proposed. [ABSTRACT FROM AUTHOR]

Solid state Na-CO2 batteries are a kind of promising energy storage system, which can use excess CO2 for electrochemical energy storage. They not only have high theoretical energy densities, but also feature a high safety level of solid-state batteries and low cost owing to abundant sodium metal resources. Although many efforts have been made, the practical application of Na-CO2 battery technology is still hampered by some crucial challenges, including short cycle life, high charging potential, poor rate performance and lower specific full discharge capacity. This paper systematically reviews the recent research advances in Na-CO2 batteries in terms of understanding the mechanism of CO2 reduction, carbonate formation and decomposition reaction, design strategies of cathode electrocatalysts, solid electrolytes and their interface design. In addition, the application of advanced in situ characterization techniques and theoretical calculation of metal–CO2 batteries are briefly introduced, and the combination of theory and experiment in the research of battery materials is discussed as well. Finally, the opportunities and key challenges of solid-state Na-CO2 electrochemical systems in the carbon-neutral era are presented. [ABSTRACT FROM AUTHOR]

Applying clean energy is one of the feasible paths to achieve the "dual carbon target". Hydrogen energy, as an efficient and clean energy, is a new growth point for creating industrial transformation and upgrading. Ammonia is recognized as a zero-carbon hydrogen energy carrier, and utilizing hydrogen through hydrogen production from ammonia decomposition is one of the effective ways to safely store, transport and utilize hydrogen energy. In addition, there are many methods to realize the hydrogen production from ammonia, among which the method based on the combination of non-thermal plasma (NTP) and catalyst can reduce the reaction temperature, significantly improve ammonia (NH 3) conversion efficiency and hydrogen energy yield. As one of the methods with good application prospects, the interaction between NTP and catalyst in this method is complicated, and the efficiency of hydrogen production from ammonia is also affected by various factors, which restricts application of the method. In order to provide new ideas for the development and commercial application of NTP-catalytic technology for ammonia decomposition, this paper reviews the progress of NTP-catalytic hydrogen production from ammonia based on a systematic and integrated literature review methodology, analyses the effects of process parameters, temperature, catalyst, and other factors on the efficiency of plasma-catalytic ammonia decomposition, and discusses the plasma source and the mechanism of plasma-catalytic ammonia decomposition reaction. Finally, the opportunities and challenges of this plasma catalysis method are described. • The progress of low-temperature plasma-catalytic NH 3 decomposition was summarized. • Three factors affecting plasma-catalytic NH 3 decomposition reaction were analyzed. • The mechanism of plasma-catalytic NH 3 decomposition were presented. • Opportunities and challenges for plasma-catalytic NH 3 decomposition were outlined. • Low-temperature plasma catalysis can significantly improve the NH 3 conversion. [ABSTRACT FROM AUTHOR]

Anhydride-cured epoxy is a common insulating material used in electrical equipment, but recycling it effectively is difficult, which results in the overall abandonment of the equipment after decommissioning and serious environmental pollution. In order to make anhydride cured epoxy degradable while maintaining its electrical performance, we synthesized a high-performance epoxy insulating material that can be recycled and reused using triethanolamine as a transesterification catalyst co-accelerator. Results show that the new epoxy has the lowest dielectric loss of 0.0012, the highest breakdown strength of 42.26 kV mm−1, and the highest tensile strength of 93.7 MPa. The degradable epoxy can be recovered via mechanical hot pressing and regenerated through chemical degradation. Degradation products can be directly used as curing accelerators to complete the re-preparation of the insulating material. Even after recovery, the properties of the epoxy resin meet the application requirements of insulating materials. [ABSTRACT FROM AUTHOR]

Ultrafine materials with unique characteristics have a broad range of utilization. The motivation of this paper was to investigate the size effect on the thermo-oxidative degradation behaviors and chemical kinetics of polystyrene (PS) solid particles. In this study, microscopic PS particles with four different-diameter distributions, containing 5, 10, 15, and 50 μm, were picked as tested samples. Then, the thermogravimetry analysis test of PS samples was conducted under an air atmosphere with three different heating rates. Activation energies were calculated and validated by multiple traditional kinetic approaches, and a linear relationship between activation energy and the reciprocal of the particle diameter has been concluded. A distributed activation energy model (DAEM) with two pseudo-components was developed and employed to decouple the polyurethane pyrolysis in the air atmosphere. A set of nth-order reactions is hypothesized to occur with a constant pre-exponential factor and having a continuous activation energy distribution pattern conforming to the Gaussian density function in each kinetic process. A multi-parameter optimization program was developed to calculate ten DAEM parameters based on the experimental data from three different heating rates by avoiding the ill condition resulting from the kinetic compensation effect. Moreover, the numerical relationship between activation energies and particle diameter has been analyzed. The results of this study are instructive for the determination method of kinetic triplets, the modification of reaction models, and especially the construction of waste polymer kinetics and combustion models. [ABSTRACT FROM AUTHOR]