Chemical Composition Distribution Research Articles

Chemically Resolved Respiratory Deposition of Ultrafine Particles Characterized by Number Concentration in the Urban Atmosphere.

Ultrafine particles (UFPs) dominate the atmospheric particles in number concentration, impacting human health and climate change. However, existing studies primarily rely on mass-based approaches, leading to a restricted understanding of the number-based and chemically resolved health effects of atmospheric UFPs. In this study, we utilized a high-mass-resolution single-particle aerosol mass spectrometer to investigate the online chemical composition and number size distribution of ultrafine, fine, and coarse particles during the summertime in urban Shenzhen, China. Human respiratory deposition dose assessments of particles with varying chemical compositions were further conducted by a respiratory deposition model. The results showed that during our observation, particles containing elemental carbon (EC) were the dominant components in UFPs (0.05-0.1 μm). Compared to fine and coarse particles, UFPs can deposit more deeply into the respiratory tract with a daily dose of ∼2.08 ± 0.67 billion particles. Among the deposited UFPs, EC-cluster particles constituted ∼85.7% in number fraction, accounting for a daily number dose of ∼1.78 billion particles, which poses a greater impact on human health. Simultaneously, we found discrepancies in the chemically resolved particle depositions among number-, surface area-, and mass-based approaches, emphasizing the importance of an appropriate metric for particle health-risk evaluation.

Spatiotemporal Active Phase Evolution for CO2 Electrocatalysis

Transition-metal-based solid-state electrocatalysts undergo dynamic phase transformation governed by the local electrochemical environment during operation, e.g., oxygen evolution/reduction(1,2), hydrogen evolution(3), and carbon dioxide reduction(4). Electrochemical active species, often hidden before operation, can become evolved due to the applied electrochemical potential and/or surrounding chemicals. These species are stabilized under the local environment dynamically generated by the reaction product, e.g., proton (H+) or hydroxyl (OH-) group(5,6).Active species often account for a small fraction (i.e., minor motif) of the entire catalyst volume, and the nanoscale morphology and chemical composition of the electrocatalyst are inhomogeneous and continuously change during the electrochemical reaction. Thus, capturing the active species remains a major challenge. Spatiotemporal observation of the structural/chemical changes of the electrocatalyst and the correlation with the local electrochemical environment may reveal the active species and elucidate the governing step toward their formation. Furthermore, identification of the key intermediate step of catalyst phase transformation allows the redirection of low- to high-active catalysts; however, this remains challenging.During electrochemical CO2 reduction (ECR), (hydr)oxide-derived Cu electrocatalysts experience significant phase transformation and show high activity and selectivity for carbon dimerization (C–C coupling)(7,8,9). The location and chemical composition of the active species evolving during electrochemical phase transformation may be strongly heterogeneous; however, these species have not been clearly determined. Recent studies have employed operando characterization techniques, e.g., fluorescence hard/soft X-ray(4,10), X-ray photoelectron(11), and Raman spectroscopy(6), to elucidate the active species responsible for high C–C coupling activity. However, although these techniques could track the changes in chemical composition of the electrocatalysts during operation, they did not reveal the spatiotemporal evolution of the active species or existence of minor motifs, owing to their inefficient chemical sensitivity. Thus, it is imperative to develop an operando analysis technique that can probe the nanoscopic chemical composition with high spatial/temporal resolution and sufficient detection limit.By observing the chemical and morphological evolution of highly efficient ECR catalysts during operation, we identified the key intermediate species toward highly active surfaces and significantly enhanced the C–C coupling activity. Operando transmission soft X-ray microscopy(1,12,13), which visualizes the nanoscale chemical composition distribution of Cu-based catalysts during ECR, revealed that partially evolved Cu+ phases and surface Cu2+ phases are responsible for the dynamic dissolution–redeposition process(4,8) and improvement of C–C coupling activity, respectively. We further demonstrated that the dissolution–redeposition process is electrochemically triggered by inducing Cu+ phases, which are redirected to copper-carbonate-hydroxide species(6,14,15) even under high cathodic potentials. DFT calculations suggest that these cationic Cu species potentially serve as active species and/or assistive sites for enhancing C–C coupling activity.(1) Mefford, J. T., et al. Nature 593(7857), 67-73 (2021)(2) Kreider, M. E., et al. ACS Applied Materials & Interfaces 11(30), 26863-26871 (2019)(3) Zhai, L., et al. ACS Energy Letters 5(8), 2483-2491 (2020)(4) De Luna, P., et al. Nature Catalysis 1(2), 103-110 (2018)(5) Wang, Y., et al. Nature Catalysis 3(2), 98-106 (2020)(6) Henckel, D. A., et al. ACS Catalysis 11(1), 255-263 (2021)(7) Lee, S. Y., et al. Journal of the American Chemical Society 140(28), 8681-8689 (2018)(8) Zhong, D., et al. Angewandte Chemie International Edition 60(9), 4879-4885 (2021)(9) Lei, Q., et al. Journal of the American Chemical Society 142(9), 4213-4222 (2020)(10) Eilert, A., et al. The Journal of Physical Chemistry Letters 7(8), 1466-1470 (2016)(11) Arán-Ais, R. M., et al. Nature Energy 5(4), 317-325 (2020)(12) Lim, J. et al. Science 353, 566–571 (2016)(13) de Smit, E., et al. Nature 456(7219), 222-225 (2008)(14) Spodaryk, M., et al. Electrochimica Acta 297, 55-60 (2019)(15) Jiang, S., et al. ChemSusChem 15(8), e202102506 (2022) Figure 1

Muscular and Edible Organ Meat Chemical Composition, Macro and Micro-Elements Distribution and Subcutaneous Fat Properties of Camel and Beef Cattle Calves.

Muscular and Edible Organ Meat Chemical Composition, Macro and Micro-Elements Distribution and Subcutaneous Fat Properties of Camel and Beef Cattle Calves.

Processing and microstructure development of reactive sintered (Ti-Zr-Nb-Hf-Ta)B2 + (Ti-Zr-Nb-Hf-Ta)C high-entropy ceramics

A novel dual-phase (Ti-Zr-Nb-Hf-Ta)B2 + (Ti-Zr-Nb-Hf-Ta)C high-entropy, compositionally complex composite was synthesized by reactive spark plasma sintering using commercial ZrB2, NbB2, HfB2, TaB2 and TiC powders as starting materials. The composite with high density, consists predominantly of boride (~39.7 vol.%) and carbide (~56.4 vol.%) phases and with residual amount of (Hf-Zr)O2. The microstructure is homogenous and relatively fine due to the reaction and solid solution coupling effect with average grain sizes of 3.4 μm and 2.2 μm of the boride and carbide phases, respectively. Large-area SEM analyses confirmed no microcracks or micropore formation and no presence of large grains or clusters. Investigation from micro to nano and atomic level, focused on local chemical composition and spatial distribution of constituent elements, revealed that Ti preferentially dissolves into the boride and all other elements to the carbide phase creating a (Ti0.82Zr0.04Nb0.08Hf0.03Ta0.03)B2 + (Ti0.49Zr0.12Nb0.13Hf0.11Ta0.15)C system. The analysis of grain and phase boundary interfaces revealed a continuous, <1.5nm wide, segregation of impurity atoms of Fe and Co. Continuous (>20nm) and atomically flat basal interfacial termination planes (001) decorated with monoatomic Zr enriched layer in the boride phase were observed. Triple points at grain and phase boundaries exhibit typical chemical composition rich in Si (40at.%), Co (35at.%), Fe (20at.%), and Ni (5at.%).

Effect of MgO/ZnO ratio on the formation process of MgxZn1-xO ceramics

The structural characteristics, chemical composition, and element spatial distribution in MgxZn1-xO ceramics were investigated using X-ray diffraction, scanning electron microscopy, Auger spectroscopy, energy-dispersive X-ray spectroscopy, and cathodoluminescence techniques. The study revealed that the morphology of the ceramic samples, as well as the mechanism of solid solution formation, depend on the relative contribution of both oxides in the charge. It was discovered that hexagonal and cubic phases of the solid solution were found to form simultaneously. An increase in the MgO content in the charge results in the magnesium content rise in the hexagonal grains continuously, reaching approximately 13 at.%. It was discovered an enrichment of grain boundaries with zinc and magnesium playing a significant role in doping ZnO and MgO particles. Obtained results allowed to propose two mechanisms involved in the formation of solid solution ceramics: i) diffusion of Mg and Zn along grain boundaries, followed by their incorporation into ZnO or MgO particles, respectively, and ii) interdiffusion of Mg into ZnO and Zn into MgO due to direct contact of ZnO and MgO grains. The second mechanism appears to dominate when both ZnO and MgO contribute comparably, increasing the probability of their direct contact. This study significantly advances the understanding of the process of the formation of MgxZn1-xO ceramics under thermodynamic conditions. These insights are crucial for optimizing the doping process and improving the material properties, thereby promoting innovations in the ceramics industry.

Anthropogenic and biogenic pollutants in a forested environment: SPRUCE-22 campaign overview

The SPRUCE-22 field campaign was conducted during July 2022 on a remote mountainous forested site in Greece to assess interactions of biogenic and anthropogenic pollutants in the Eastern Mediterranean. Particle chemical composition and size distributions along with concentrations of organic and inorganic gases were measured at high temporal resolution, while samples were collected and analyzed off-line. PM1 had a surprisingly high average concentration of 13 μg m−3 consisting primarily of organics (57%), followed by sulfate (30%), ammonium (9%), and black carbon (2%). Nitrates (both inorganic and organic) were less than 1% of the PM1 despite the relatively high NOx emissions in the Balkans. The PM2.5 concentrations at this remote site were similar and even higher than those in major cities across Greece including Athens, indicating the importance of regional transport for summertime pollution in the Eastern Mediterranean. The relatively constant average diurnal profiles of major anthropogenic pollutants are consistent with only minimal effects from local sources. Sulfates are not any more the dominant component of fine PM in Greece due to the reduction of SO2 emissions of coal-burning powerplants. The organic aerosol (OA) was quite oxidized with an average oxygen to carbon ratio (O:C) equal to 0.83. The average concentration of isoprene was 0.6 ppb, of monoterpenes 0.5 ppb, while the biogenic secondary organic aerosol factor (obtained through source apportionment analysis) was estimated to contribute 22% of the OA. Additional biogenic secondary organic aerosol (SOA) may be part of the two oxygenated OA (OOA) factors that were also identified. Radiocarbon analysis indicated that the non-fossil carbon was approximately equal to the sum of the biogenic and the more oxidized oxygenated OA, implying that the less oxidized OOA in this study was mostly associated to anthropogenic fossil fuel combustion. The biogenic SOA was quite aged (O:C equal to 0.63) and was also mostly transported to the site. Nearby new particle formation events occurred during 20 % of the days, with an average SO2 concentration of 0.3 ppb. The oxidative potential of the PM per unit of mass was quite high. The source attribution of the fine PM and the interactions among its anthropogenic and biogenic components are also discussed.

Regulating Anode-electrolyte Interphasial Reactions by Zwitterionic Binder Chemistry in Lithium-ion Batteries with High-nickel Layered Oxide Cathodes and Silicon-Graphite Anodes.

The practical application of silicon (Si)-based anodes faces challenges due to severe structural and interphasial degradations. These challenges are exacerbated in lithium-ion batteries (LIBs) employing Si-based anodes with high-nickel layered oxide cathodes, as significant transition-metal crossover catalyzes serious parasitic side reactions, leading to faster cell failure. While enhancing the mechanical properties of polymer binders has been acknowledged as an effective means of improving solid-electrolyte interphase (SEI) stability on Si-based anodes, an in-depth understanding of how the binder chemistry influences the SEI is lacking. Herein, a zwitterionic binder with an ability to manipulate the chemical composition and spatial distribution of the SEI layer is designed for Si-based anodes. It is evidenced that the electrically charged microenvironment created by the zwitterionic species alters the solvation environment on the Si-based anode, featuring rich anions and weakened Li+-solvent interactions. Such a binder-regulated solvation environment induces a thin, uniform, robust SEI on Si-based anodes, which is found to be the key to withstanding transition-metal deposition and minimizing their detrimental impact on catalyzing electrolyte decomposition and devitalizing bulk Si. As a result, albeit possessing comparable mechanical properties to those of commercial binders, the zwitterionic binder enables superior cycling performances in high-energy-density LIBs under demanding operating conditions.

Functionality-type and chemical-composition separation of poly(lactide-co-glycolide) using gradient elution normal-phase liquid chromatography with basic and acidic additives

End groups of poly(Lactide-co-glycolide) (PLGA) play an important role in determining the properties of polymers for use in drug delivery systems. For instance, it has been reported that the encapsulation efficiency in PLGA microspheres varies significantly between ester-terminated and acid-terminated PLGA. More importantly, the in-vivo degradation time of such polymer excipients is influenced by the functional end-group of the copolymer used.The end group distribution in PLGA polymers has been studied using electrospray and matrix-assisted laser-desorption/ionization – high-resolution mass spectrometry. In both cases, the application of these methods is typically limited to PLGA having a molecular weight of up to 4 kDa. 13Carbon-nuclear-magnetic-resonance has also been reported as a method to differentiate and quantify PLGA end groups with a molecular weight up to 136 kDa. However, reported NMR methods take over 12 h per sample, limiting throughput.Cryoprobe NMR can reduce the time required for the process, however such NMR equipment is costly, which makes it unsuitable for the quality control of PLGA.Here, we present a normal-phase liquid chromatography method capable of resolving functionality type distribution (FTD) and, partially, chemical composition distribution (CCD) in commercial PLGA polymers obtained from ring opening polymerization. This method can separate PLGA polymers with a molecular weight of up to 183.0 kDa while also enabling the simultaneous separation of the difference of Lactic acid (LA)/Glycolic acid (GA) ratios.To achieve this, a cross-linked diol column was used with a ternary gradient from HEX to 0.1 % v/v TEA in EA to 0.1 % v/v FA in THF to allow first for the elution of mono-ester terminated PLGA, followed by the di-acid terminated. In addition, a separation of ester-terminated PLGA in the difference of the LA/GA ratio was achieved.This method is expected to aid in understanding the correlation between PLGA's FTD, CCD, and physical properties, facilitating product development and quality control.

Effect of solvent type on chemical composition distribution analysis of polyolefins using crystallization elution fractionation (CEF)

For microstructure characterization of polyolefin by separation-based techniques with infrared detector, either 1,2-dichlorobenzene (o-DCB) or 1,2,4-trichlorobenzene (TCB) is commonly selected as a dissolution solvent and mobile phase. Herein, we studied the effects of o-DCB and TCB on the comonomer detection and chemical composition distribution (CCD) by crystallization elution fractionation (CEF) with a filter-based IR detector. We first compared the detector sensitivity on methyl group content or short chain branching (SCB) in polyethylene-co-butene with varied sample concentrations in o-DCB and TCB. TCB demonstrated superior comonomer detection in the IR detector with a single linear calibration across a wide range of sample concentrations. In contrast, o-DCB displayed stronger concentration dependent methyl group response, requiring a more complex equation in the calibration. Furthermore, o-DCB provided better separation of comonomer distribution with less peak broadening and co-crystallization effects, as observed with various polyolefins, including high density polyethylene (HDPE), linear low-density polyethylene (LLDPE), polypropylene (PP), and ethylene-propylene copolymer (EP).

Supercapacitive investigation of polyazomethine incorporating electron-withdrawing Nitro Group: Room temperature synthesis

A polyazomethine, designated as NAZ, was synthesized effortlessly at room temperature via a highly efficient polycondensation route employing 5,5′-(4-nitro-1,2-phenylene)bis(furan-2-carbaldehyde) (III) as a monomer, along with a diverse array of diamines meticulously selected for engineering the NAZ polyazomethine. The resulting NAZ material underwent a comprehensive characterization employing cutting-edge techniques including X-ray diffraction (XRD), the random morphology of polyazomethine has revealed in FESEM and TEM images, energy dispersive X-ray analysis (EDAX), and a suite of advanced spectroscopic methods. In the realm of Fourier-transform infrared spectroscopy (FTIR), the emergence of the distinctive –CHN– peak at 1608 cm−1 unequivocally validated the triumphant conversion of dicarbaldehyde (III) and diamines into the desired polyazomethine structure. XRD diffractograph unveiled the tantalizingly amorphous disposition of NAZ, while the FESEM images elegantly revealed its enigmatic and inherently random morphology. The EDAX analysis, meanwhile, provided an exquisite insight into the intricate chemical composition and elemental distribution meticulously orchestrated on the surface of NAZ. Delving into the electrochemical domain, the synthesized polyazomethine electrodes were subjected to a rigorous battery of tests including cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and the formidable electrochemical impedance spectroscopy (EIS). The superlative supercapacitive prowess of the NAZ electrodes were fervently evaluated across a plethora of electrolytic environments encompassing NaOH, LiCl, NaNO2, and the venerable KOH, spanning an impressive range of concentrations. Noteworthy is the awe-inspiring performance of the NAZ electrode in the hallowed 1 M KOH electrolyte, boasting an unprecedented specific capacitance (Cp) of 860 Fg−1, specific energy (SE) soaring to an impressive 6.14 Whrkg−1, and specific power (SP) scaling the summit at a staggering 74 KWkg−1, thus epitomizing optimal performance in every facet.Furthermore, the indomitable NAZ electrode exhibited an unparalleled degree of stability, steadfastly retaining a remarkable 69.25 % of its initial capacitance even after being subjected to the rigorous crucible of successive 1000 cycles within the exacting confines of the 1 M KOH electrolyte.

Ameliorating dilution of Cr and Ni and improving PWSCC resistance of 52 M overlay by hot wire plasma arc cladding

The multi-scale chemical composition distribution and microstructure of Alloy 52 M overlay on low alloy steel by hot wire plasma arc cladding (HWPC) were characterized. Stress corrosion cracking (SCC) growth rates were quantified in the dilution zone (DZ) near the fusion boundary and in the bulk of Alloy 52 M using compact tension samples with a thickened cladding overlay. The DZ of the Alloy 52 M side exhibited a single macroscopic dilution zone containing approximately 27–28 wt% Cr and 50 wt% Ni, in contrast to the multiple dilution zones observed in the DZ of Alloy 52 M overlays or joints prepared using other welding technologies such as submerged arc welding (SMAW). The DZ of the HWPC overlay exhibited less dilution of Cr and Ni compared to SMAW weldment. This resulted in a shorter average SCC band and fewer local intergranular cracks in the DZ of HWPC, as observed from SCC crack growth rate specimens tested in simulated PWR primary water at 325 °C and 350 °C. These findings highlight the advantages of utilizing HWPC to enhance SCC resistance in the DZ of Alloy 52 M overlays over conventional cladding technologies.

Analysis of Blackening Reaction of Zn–Mg–Al Alloy Coated Steel Prepared by Anodizing Process

The rising demand for black-treated steel faces challenges with conventional black painting due to issues like scratching and peeling, impacting corrosion resistance and aesthetics. This study explores an alternative method, anodic oxidation, to blacken the surfaces of galvanized or coated steel plates. Parameters like temperature, duration, current density, and gas type were varied during the blackening process. The investigation aimed to identify key factors influencing the blackening. Scanning electron microscopy observed the morphology, while energy-dispersive X-ray spectroscopy and glow discharge mass spectrometry analyzed the chemical composition distribution. X-ray diffraction and X-ray photoelectron spectroscopy conducted compound crystal structure analysis. Results indicate higher temperatures, longer durations, and higher current densities improve blackening through anodic oxidation. Increased magnesium proportion on the surface leads to roughness and porous magnesium oxide formation, enhancing light absorption and explaining the observed blackening effect.

Changes in the magmatic plumbing system associated with the Gotemba sector collapse at Mount Fuji, Japan

It is well known that magmatic plumbing systems change over time, but there is much debate as to why and how. We studied volcanic ejecta continuously deposited in an outcrop at Kagosaka Pass at the eastern base of Mount Fuji to investigate the factors responsible for changes in the magmatic plumbing system. The sample consisted of pyroclastic sediments from explosive eruptions for approximately 3000 y, which sandwiched the time of the Gotemba sector collapse at approximately 2500 BP. Chemical analyses of whole rocks, minerals, and matrix glasses, as well as mode measurements of glass and bubbles, were performed on samples collected from approximately 30 layers; significant changes were observed before and after the collapse. For example, before and after the collapse, matrix glass area increased around 60% to over 80% and anorthite content (Ca / (Ca + Na) * 100) of phenocryst plagioclase decreased from over 80 to below 65. For a period after the collapse, possibly hundreds of years, the plagioclase and olivine phenocrysts exhibited characteristics indicative of crystallization at low temperatures and pressures, and the pyroclast matrix became highly vitreous. Eruptions with ejecta of these characteristics continued more than a dozen times, lasting about 500 years. In addition, the trend in the distribution of the bulk rock chemical composition changed significantly, showing a differentiation trend with only plagioclase and clinopyroxene crystal separation. An investigation using the MELTS software revealed that the phenomenon of direct eruptions from deep magma chambers to the surface, bypassing shallow magma reservoirs, continued for several hundred years after the collapse. This can be interpreted as a decrease in confining pressure associated with the collapse, facilitating the eruption of magma from the depths. Furthermore, based on an examination of the water content in the magma during this period, we posit that the trigger for the rise of magma from the deep magma chamber of Mount Fuji is the acquisition of excess pressure by the injection of magma from a deeper level.

Predicting the chemical composition of pet food with hyperspectral imaging

Performing fast analyses to control the nutritional quality of pet food products is of great interest in the pet food industry. The purpose of this study was to test the efficacy of near-infrared hyperspectral imaging (HSI) in determining chemical composition content of cat and dog food, and evaluate the influence of mixed model and characteristic wavelength on the performance of the quantitative model. Seventy cat food and thirty-six dog food samples were characterised using reference methods for moisture, crude protein (CP), crude fat (CF), crude fibre (CFe), crude ash (CA), calcium (Ca) and total phosphorus (TP) content. The Partial Least Squares regression (PLSR) was used to establish the quantitative models that involved the cat food model and mixed model. The characteristic wavelength was selected using a competitive adaptive reweighted-sampling (CARS) algorithm. Results showed that, except for CFe, the performance of the cat food model was similar to the mixed model. When using feature band, the prediction results of the mixed models for CP, CF, moisture, and CFe were optimized with R2p between 0.73 and 0.96 and RPD in the range 2.22–5.20, but the prediction results of TP, CA, and Ca did not meet the actual demand. Optimal quantitative models were used to visualise the sample chemical composition distributions. The results of this study provide theoretical and technical support for the rapid online quality control of pet food.

Chemical Variability, Antioxidant and Larvicidal Efficacy of EOs from Citrus sinensis (L.) Osbeck Peel, Leaf, and Flower

Essential oils (EOs) from Citrus sinensis (Rutaceae) possess diverse biological activities. However, a comprehensive comparison of their chemical composition and bioactivity across different plant parts has not been studied yet. The current research comparatively assesses the yield, chemical composition, chiral distribution, antioxidant properties, and larvicidal activity of EOs extracted from the peels, leaves, and flowers of C. sinensis. EOs extracted via hydro-distillation (HD) and steam distillation (SD) were analyzed by gas chromatography–mass spectrometry (GC-MS) and chiral GC-MS to explore their chemical composition and enantiomeric distribution. In addition, their larvicidal and antioxidant potentials were evaluated following standard protocols. Peels of C. sinensis exhibited significantly higher oil content (1.75–2.25%) compared to its leaves (0.75–0.78%) and flowers (0.20–0.25%). The GC-MS analysis identified around 60 compounds, including terpenoids, sesquiterpenoids, and oxygenated terpenoids in the HD and SD extractions. Higher concentrations of sabinene were found in flower extract (38.05–39.89%) and leaf extract (32.30–36.91%), while peel extract contained more than 90% limonene. The larvicidal activity of peel oil was primarily attributed to limonene, with an LC50 value of 0.0031 µL/mL. The current study reports the first chiral (GC-MS) analysis in the essential oil of the leaves and flowers of C. sinensis, paving the way for authenticity and purity. Furthermore, the chemical profiling of citrus EOs, particularly from the peel, demonstrates a safe and promising candidate for diverse biological applications.

Synergetic effects of Al addition on the performance of CoFe2O4 catalyst for hydrogen production and filamentous carbon formation from direct cracking of methane

Improving methane catalytic decomposition process was deemed an effective approach for hydrogen production. Here, a novel catalyst AlxCo1-xFe2O4 with a variable aluminum content was synthesized via a co-precipitation route for the direct cracking of methane. The catalytic activity of AlxCo1-xFe2O4 was performed in a fixed bed reactor at temperature of 800°C and 20 mL/min of fed gas. A sequence of characterizations, including SEM, BET, XRD, XPS, Raman and TGA for fresh and spent catalysts, was exploited to examine the influence of Alx content on the morphology, porosity, structure, chemical composition, and cation distribution of AlxCo1-xFe2O4. As the Alx content increased in AlxCo1-xFe2O4 their morphology became more fractal and decreased in particle size, lattice parameter, lattice size, while their pore surface increased. Further cation re-distributions from octahedral to tetrahedral sites as Fe3+ and Al3+ relocated in the Tetrahedral site and Oxygen lattice decreased as observed from Raman and XPS results. Catalytic activity studies showed that Alx content of 0.6 in AlxCo1-xFe2O4 lead maximum methane conversion up to ∼ 91.10 % and hydrogen formation rate of 1.780 ×10-3 mol H2 g-1 s-1. The catalytic activity behavior was explained in correlation with the characteristics of spent catalysts.

The regional climate–chemistry–ecology coupling model RegCM-Chem (v4.6)–YIBs (v1.0): development and application

Abstract. The interactions between the terrestrial biosphere, atmospheric chemistry, and climate involve complex feedbacks that have traditionally been modeled separately. We present a new framework that couples the Yale Interactive terrestrial Biosphere (YIBs) model, a dynamic plant-chemistry model, with the RegCM-Chem model. RegCM-Chem–YIBs integrates meteorological variables and atmospheric chemical composition from RegCM-Chem with land surface parameters from YIBs. The terrestrial carbon flux calculated by YIBs is fed back into RegCM-Chem interactively, thereby representing the interactions between fine particulate matter (PM2.5), ozone (O3), and carbon dioxide (CO2). For testing purposes, we carry out a 1-year simulation (2016) at a 30 km horizontal resolution over East Asia with RegCM-Chem–YIBs. The model accurately captures the spatio-temporal distribution of climate, chemical composition, and ecological parameters. In particular, the estimated O3 and PM2.5 are consistent with ground observations, with correlation coefficients (R) of 0.74 and 0.65, respectively. The simulated CO2 concentration is consistent with observations from six sites (R ranged from 0.89 to 0.97) and exhibits a similar spatial pattern when compared with carbon assimilation products. RegCM-Chem–YIBs produces reasonably good gross primary productivity (GPP) and net primary productivity (NPP), showing seasonal and spatial distributions consistent with satellite observations, and mean biases (MBs) of 0.13 and 0.05 kg C m−2 yr−1. This study illustrates that RegCM-Chem–YIBs is a valuable tool to investigate coupled interactions between the terrestrial carbon cycle, atmospheric chemistry, and climate change at a higher resolution on a regional scale.

Impact of Electronic Waste Glass on the Properties of Cementitious Materials

The article analyses the impact of two different types of dispersive glass on cement hydration and compressive strength at 7 and 28 days. The study employed dispersive glass from various LCDs (TV sets, computer monitors, smart phones), characterised by a composition of approximately 8% SrO, and dispersive glass from washing machines, which consists mainly of SiO2, Na2O, and CaO. The chemical composition and particle-size distribution of different types of dispersive glass were analysed. The study compares the effect of electronic waste glass on cement hydration by evaluating the amount and rate of heat released during the process. In addition, the results of X-ray diffraction (XRD), thermogravimetric analysis (TG), and scanning electron microscopy (SEM) are provided. Different types of glass were determined to have a similar effect on the physical and mechanical properties as well as the mineral composition of cementitious samples: density and UPV decrease up to 6% and compressive strength decreases by about 30%, when 5–20% of cement was replaced by glass waste. However, more prominent differences were observed in the workability of the mixtures: the waste glass from home appliances increased the spread by up to 25%, while the waste glass from electronic devices decreased the spread compared to the reference sample by approximately 20%. The mixtures modified with the waste glass of electronic devices had a higher degree of early hydration (96%) due to the higher water absorption of the mixtures compared to the waste glass of home appliances (88%).

Structural Evolution of GaOx-Shell and Intermetallic Phases in Ga-Pt Supported Catalytically Active Liquid Metal Solutions.

We present a comprehensive scale-bridging characterization approach for supported catalytically active liquid metal solutions (SCALMS) which combines lab-based X-ray microscopy, nano X-ray computed tomography (nano-CT), and correlative analytical transmission electron microscopy. SCALMS catalysts consist of low-melting alloy particles and have demonstrated high catalytic activity, selectivity, and long-term stability in propane dehydrogenation (PDH). We established an identical-location nano-CT workflow which allows us to reveal site-specific changes of Ga-Pt SCALMS before and after PDH. These observations are complemented by analytical transmission electron microscopy investigations providing information on the structure, chemical composition, and phase distribution of individual SCALMS particles. Key findings of this combined microscopic approach include (i) structural evolution of the SCALMS particles' GaOx shell, (ii) Pt segregation toward the oxide shell leading to the formation of Ga-Pt intermetallic phases, and (iii) cracking of the oxide shell accompanied by the release of liquid Ga-Pt toward the porous support.

Preparation and properties evaluation of high-entropy (La0.2Nd0.2Sm0.2Eu0.2Gd0.2)MgAl11O19 for advanced thermal barrier coating

LaMgAl11O19 (LMA) with magnetoplumbite structure has emerged as a promising candidate for thermal barrier coating (TBC). However, the inherent high thermal conductivity and relatively low thermal expansion coefficient (TEC) of LMA impose limitations on its further application. In this work, a novel high-entropy hexaluminate (La0.2Nd0.2Sm0.2Eu0.2Gd0.2)MgAl11O19 (HE-LMA) has been designed and prepared to overcome these obstacles. HE-LMA with homogeneous chemical composition distribution possesses excellent phase stability up to 1600°C. Moreover, the TEC of HE-LMA (9.22 × 10−6 K−1 at 1300°C) is larger than that of LMA. The high-entropy strategy effectively decreases the thermal conductivity of HE-LMA (from 3.27 W/(m⋅K) at room temperature to 2.19 W/(m∙K) at 1000°C) in comparison to that of LMA (3.63–2.62 W/(m∙K)). Furthermore, HE-LMA demonstrates higher microhardness and fracture toughness due to the lattice distortion. These results indicate that (La0.2Nd0.2Sm0.2Eu0.2Gd0.2)MgAl11O19 has the potential to be applied as a TBC.