Nitrogen Atmosphere Research Articles

Construction of Fe and g-C3N4 codoped magnetic bamboo charcoal for enhanced catalytic degradation of tetracycline: Mechanism, degradation pathway, and ecological toxicity.

The well-designed bamboo charcoal (BC) composite Fe-g-C3N4/BC with multi-active sites of FeOx, FeNx, and g-C3N4, was fabricated in-situ by calcining Fe-melamine loaded bamboo charcoal (Fe-Me-BC) under nitrogen atmosphere. The as-synthesized Fe-g-C3N4/BC(550) exhibited a mesoporous structure with a large specific surface area of 108.23m2/g. The adsorption of tetracycline (TCL) on Fe-g-C3N4/BC(550) was calculated following the Langmuir isotherm model, and showed a maximum adsorption capacity of 19.92mg/g. Furthermore, the pseudo-second-order kinetic model showed a good fit for the TCL adsorption process on Fe-g-C3N4/BC(550). The Fe-g-C3N4/BC(550)/H2O2 system exhibited excellent photo-Fenton catalytic performance in degrading TCL with a degradation efficiency reaching up to 98.9% within 5min under visible-light. The effects of initial pH value and coexisting anions on TCL degradation were determined. As narrow band gap semiconductors, g-C3N4, Fe3O4, and Fe2O3 in the Fe-g-C3N4/BC exhibited good visible-light-driven photocatalytic activity. Moreover, photogenerated electrons could further activate H2O2 to produce high concentrations of ∙OH radicals. This outstanding photo-Fenton catalytic performance can be ascribed to the synergistic effect of g-C3N4/Fe3O4-Fe2O3/FexN multi-active sites as well as the excellent adsorption ability and conductivity provided by bamboo charcoal. This work presents a convenient approach for constructing economical catalysts for environmental remediation through g-C3N4 and Fe-N codoped BC.

Magnetic biochar generated from oil-mill wastewater by microwave-assisted hydrothermal treatment for sonocatalytic antibiotic degradation

The pollution risks of biomass-containing and antibiotics-containing wastewater mean that it must be treated before discharge into the environment. In a process following circular economy principles, oil-mill wastewater (OMWW) was treated in a microwave-assisted hydrothermal process and with simultaneously fabricated magnetic biochar (MBC), which was used as a catalyst for the sonocatalytic degradation of antibiotics metronidazole (MET) and ciprofloxacin (CIP) in aqueous solutions. FeCl3·6H2O, FeCl2·4H2O, and KOH were added to the OMWW, which was then treated in a SynthWave microwave reactor under either a nitrogen or air atmosphere. The UV254 and COD removal efficiencies of the OMWW reached 42.3% and 60.6%, respectively, after treatment at 250 ℃ for 3h. The MBC obtained from the OMWW treatment with air exhibited the highest adsorption and catalytic activity for antibiotics degradation. The synergistic effects of combining adsorption and sonolytic removal were in the ranges of 0.76-3.07 (MET) and 0.75-3.17 (CIP), resulting in significant degradation rate constants of pseudo-first-order kinetics (k1) that ranged from 0.010 to 0.086min-1 (MET) and from 0.018 to 0.050min-1 (CIP). Hydrophobic MET underwent faster degradation than hydrophilic CIP. The •OH is crucial for removing the model antibiotics. Initial antibiotics concentration, reaction volume, ultrasonic frequency, and power had clearer impacts on antibiotics degradation than bulk temperature. Furthermore, the possible sonocatalytic degradation pathways have also been proposed herein. The absorbents and catalysts were derived during the purification of OMWW and subsequently used for antibiotics removal from water, becoming an innovative case of circular economy and sustainable waste treatment.

Impact of Layering Strategies on the Properties of In Situ Synthesized TiN/TC4 Laminated Materials via Laser‐Directed Energy Deposition

Laser‐directed energy deposition (LDED) additive manufacturing presents significant advantages for fabricating laminated materials with enhanced mechanical properties. This study investigates the in situ synthesis of TiN/TC4 laminated materials, developed using different layering strategies in the LDED process under alternating atmospheres of pure argon and nitrogen–argon gas mixtures. The effects of these layering strategies on the microstructure and mechanical properties of the synthesized materials are systematically analyzed. As the proportion of in situ synthesized layers increases, significant microstructural evolution is observed: the average grain size increases, the structure transitions from a Widmanstätten pattern to a basketweave structure, and the grain morphology shifts from columnar to equiaxed crystals. Correspondingly, the elongation at fracture decreases, while tensile strength initially increases and then declines. Notably, the 2‐1 layering strategy achieves a peak tensile strength of 1135.0 ± 26.8 MPa, reflecting a 21.6% improvement compared to titanium alloy samples fabricated in a pure argon atmosphere. This study highlights the versatility of combining LDED with controlled deposition atmospheres to enable the tailored synthesis of laminated materials. The ability to manipulate microstructure and mechanical properties through specific layering strategies offers significant potential for advancing the development and application of high‐performance laminated materials.

Genome-Wide Identification and Characterization of Heat Shock Proteins in the Stored-Product Pest Rhyzopertha dominica (Fabricius): Phylogenetic, Structural, and Stress-Induced Expression Analyses

Heat shock proteins (HSPs) are crucial molecular chaperones that help organisms maintain protein stability under stress conditions. As a major stored-product pest, Rhyzopertha dominica (Fabricius) faces distinct stresses compared to field insects, primarily due to the specific pest control methods applied during grain storage. In this study, a total of 53 HSP genes from five gene families (HSP90, HSP70, HSP60, sHSP, and DnaJ) were identified and characterized using bioinformatics methods. Among them, DnaJ was the largest and the most diverse HSP family in R. dominica. Transcriptome sequencing and RT-qPCR were then used to evaluate HSP gene expression patterns under four storage-related stresses, following a series of bioassays. Extreme high temperature was the strongest inducer of HSP expression, with 12 genes showing over a 10-fold increase. Controlled nitrogen atmosphere also led to considerable upregulation of HSP genes, especially in the HSP70 family. In contrast, phosphine fumigation and K-Obiol grain protectant caused very limited induction of HSP genes, which might have been due to the less severe protein damage caused by chemical stresses compared to physical stresses. Our study provides a theoretical basis for further research on HSP functions in R. dominica.

Detection of Atmospheric NO2 Using Scheimpflug DIAL with a Blue External Cavity Diode Laser Source

Nitrogen dioxide (NO2) is broadly acknowledged as one of the six key air pollutants, posing a significant threat to environmental stability and human health. The profile of atmospheric nitrogen dioxide is required for quantifying NO2 emissions from fossil fuel combustion and industry. In continuous-wave differential absorption lidar (CW-DIAL) systems, the laser sources employed are subject to the issues of varying output characteristics and poor instability. This study presents a CW-DIAL system for remote sensing of atmospheric NO2 that employs a compact grating-based external cavity diode laser (ECDL) and Scheimpflug imaging. The laser in this system utilizes a piezoelectric transducer (PZT) for precise wavelength tuning, emitting at 448.1 nm and 449.7 nm with an output power of 2.97 W and a narrow linewidth of 0.16 nm. Signal capturing was achieved through a Newtonian telescope with a diameter of 200 mm and a 45° inclined CCD image sensor, satisfying the Scheimpflug principle. A case study near road traffic was used to verify the feasibility of ECDL-DIAL, which took place from 1 October to 2 October 2023 over an industrial park. The system generates precise NO2 distribution maps with sub-50 m resolution over 3 km, updating every 10 min.

Flame retardancy and durability of cotton fabric modified with high-efficiency diboraspiro rings groups flame retardant.

The synthesis of highly efficient and environmentally friendly flame retardants through the synergistic interaction of boron, phosphorus and nitrogen is becoming a new research direction. In this study, N-DBSPA, a flame retardant with high flame retardancy, high thermal stability and high efficiency, was prepared by the reaction between pentaerythritol borate and amino trimethylene phosphate, and the limiting oxygen index (LOI) of the modified cotton fabric increased from 18 % to 44.7 % at a weight gain (WG) of 20.4 %. After 50 wash cycles (LCs), it still reached 34.2 % and passed the Vertical Flame Test (VFT), indicating good flame retardancy and wash resistance. Cone Calorimetry Test (CCT) showed a 90.2 % reduction in Peak Heat Release Rate (PHRR) and a 32.9 % reduction in Total Heat Release (THR). The thermogravimetric test (TG) showed an increase in the charring residue of cotton fabrics from 10.9 % to 36.2 % at 750 °C in a nitrogen atmosphere. Finally, the flame retardant mechanism of the modified cotton fibers was speculated from the condensed phase and gas phase, respectively.

Pyrolysis Characteristics of Aramid Fiber/Phenolic Resin Composites

ABSTRACT In this study, pyrolysis characteristic laws of aramid fiber/phenolic resin composites were investigated by thermogravimetry and differential thermal analysis. The pyrolysis process under air atmosphere was divided into three stages with initial pyrolysis temperatures of 248°C, 495°C and 832°C. The pyrolysis process under nitrogen atmosphere was divided into two stages with initial pyrolysis temperatures of 271°C and 538°C. Focusing on the pyrolysis behavior and the kinetic analysis associated with different heating rates under nitrogen atmosphere, the initial pyrolysis temperatures of the two stages range from 248°C to 426°C and 516 to 683°C. The apparent activation energies calculated using the Kissinger, Flynn–Wall–Ozawa and Starink methods are 171.74 kJ/mol, 161.44 kJ/mol and 157.90 kJ/mol. The results of this study are important for the enhancement of composite properties, optimization of processes, and applications in aerospace and other fields.

Thermal Characterisation and Toxicity Profile of Potential Drugs from a Class of Disubstituted Heterofused Triazinones

The thermal characterisation and toxicity profile of a class of disubstituted heterofused triazinones were revealed in this article for the first time. The thermal behaviour of molecules 1–12 was investigated by means of TG and DSC analyses performed in an air atmosphere and by the coupled TG/FTIR technique in a nitrogen atmosphere. The heating atmosphere affects both the stability of compounds and the degradation mechanism. A two-step degradation occurs in air, while a one-step degradation takes place in nitrogen, both preceded by a melting process. Compound 3 shows the highest thermal stability, while molecule 10—the lowest. The thermal decomposition of the studied heterocyclic molecules begins with the degradation of the bicyclic system, resulting in the formation of volatile gaseous products such as ammonia/hydrazine, hydrogen cyanide, carbon dioxide, and isocyanates. In the further stage, mainly aromatic compounds are released, and their chemical composition depends on the presence and type of substituents at the phenyl and benzyl moieties. In addition, the toxicity profiles of molecules were assessed in the animal (zebrafish) and cellular (erythrocytes) models, and the antihaemolytic activity was evaluated in the AAPH- and H2O2-induced haemolysis inhibition assays. It was found that all the tested compounds are safe for the developing zebrafish and red blood cells, and they are able to effectively protect erythrocytes from oxidative damage. These favourable properties make them promising drug candidates suitable for further in vivo studies.

Influence of Printing Orientation on Surface Roughness and Gloss of 3D Printed Resins for Orthodontic Devices

The study aims to assess the effect of printing orientation on surface roughness and gloss of resins for 3D printing of aligners. Squared specimens (14 × 14 × 4 mm) were printed using Dental LT Clear (Formlabs, Somerville, MA, USA; LT) or Tera Harz TC-85 DAC (Graphy, Seoul, Republic of Korea; TC) with different orientations: 0° (horizontal), 90° (vertical), and as per the manufacturer’s recommendation (40° for LT, 60° for TC). A profilometer was used to measure roughness (Ra) in µm, while gloss was recorded in gloss units (GU) with a glossmeter. The collected data were statistically analyzed. Material type did not significantly influence roughness, while print orientation was an influential factor, with the orientation recommended by the manufacturer yielding the roughest specimens. Vertical printing resulted in significantly higher roughness than horizontal. Material type was a significant factor for gloss, with TC exhibiting significantly higher gloss than LT. Print direction significantly influenced gloss, with vertical printing resulting in the highest gloss. The finding of higher roughness for vertical prints can be explained by the presence of a greater number of layers. The superior gloss exhibited by TC regardless of print angulation could be related to the effective cleaning of uncured resin by centrifugation and to the high degree of monomer conversion in nitrogen atmosphere.

The greenhouse gas observation mission with Global Observing SATellite for Greenhouse gases and Water cycle (GOSAT-GW): objectives, conceptual framework and scientific contributions

The Japanese Global Observing SATellite for Greenhouse gases and Water cycle (GOSAT-GW) will be an Earth-observing satellite to conduct global observations of atmospheric carbon dioxide (CO2), methane (CH4), and nitrogen dioxide (NO2) simultaneously from a single platform. GOSAT-GW is the third satellite in the series of the currently operating Greenhouse gases Observing SATellite (GOSAT) and GOSAT-2. It will carry two sensors, the Total Anthropogenic and Natural emissions mapping SpectrOmeter-3 (TANSO-3) and the Advanced Microwave Scanning Radiometer 3 (AMSR3), with the latter dedicated to the observation of physical parameters related to the water cycle. TANSO-3 is a high-resolution grating spectrometer designed to measure reflected sunlight in the visible to short-wave infrared spectral ranges. It aims to retrieve the column-averaged dry-air mole fractions of CO2 and CH4 (denoted as XCO2 and XCH4, respectively), as well as the vertical column density of tropospheric NO2. The TANSO-3 sensor onboard GOSAT-GW will utilize the wavelength bands of 0.45, 0.76, and 1.61 µm for NO2, O2, and CO2 and CH4 retrievals, respectively. GOSAT-GW will fly in a sun-synchronous orbit with a local overpass time of approximately 13:30 and a 3-day ground-track repeat cycle. The TANSO-3 sensor has two observation modes in the push-broom operation: Wide Mode, which provides globally covered maps with a 10-km spatial resolution within 3 days, and Focus Mode, which provides snapshot maps over targeted areas with a high spatial resolution of 1–3 km. The objectives of the GOSAT-GW mission include (1) monitoring atmospheric global-mean concentrations of greenhouse gasses (GHGs), (2) verifying national anthropogenic GHG emissions inventories, and (3) detecting GHG emissions from large sources, such as megacities and power plants. A comprehensive validation exercise will be conducted to ensure that the sensor products’ quality meets the required precision to achieve the above objectives. With a projected operational lifetime of seven years, GOSAT-GW will provide vital space-based constraints on both anthropogenic and natural GHG emissions. These measurements will contribute significantly to climate change mitigation efforts, particularly by supporting the Global Stocktake (GST) mechanism, a key element of the Paris Agreement.

Thermoelectric transport properties of BaFe2Fe16O27 hexaferrites

Exploring new materials with earth-abundant and low-toxicity elements has been a long-standing goal in thermoelectrics. Hexaferrites, a family of environmentally friendly oxides, exhibit complex and tunable structures and excellent magnetic properties, but receive limited attention as potential thermoelectric materials. Here in this study, we systematically investigated the thermoelectric transport properties of W-type hexaferrites BaFe2Fe16O27 and the cobalt-substituted derivatives prepared by sintering in the nitrogen atmosphere. These materials exhibit an n-type conduction behavior and cobalt substitution can tune the electrical transport properties effectively. Low-temperature specific heat capacity analysis unravels the existence of low-energy optical phonons that contribute to damping the heat transport. Low room temperature thermal conductivity of 1.27 W m-1 K-1 is obtained, and the role of cobalt substitution on the thermal conductivity reduction is rationalized by the Debye-Callaway model. This study ‌enlightens the investigation of the thermoelectric transport properties of W-type hexaferrites BaFe2Fe16O27 and extends the scope of new thermoelectric compounds.

Mosaic Structure of GaN Film Grown on Sapphire Substrate by AP-MOCVD: Impact of Thermal Annealing on the Tilt and Twist Angles

A GaN layer with a thickness of 2 µm was grown on a sapphire substrate using atmospheric pressure metal–organic chemical vapor deposition (AP-MOCVD). Subsequently, the layer was annealed under a nitrogen atmosphere at temperatures ranging from 1000 °C to 1120 °C. High-resolution X-ray diffraction (HRXRD) analysis reveals the impact of thermal annealing on the mosaic structure of the GaN, specifically the tilt and twist variations in four planes: (00.2), (10.3), (10.2), and (10.1). Interestingly, the observed trends suggest a differential effect of annealing on screw and edge dislocation densities. The annealing process reduces the edge and screw dislocation density. Lower values (Dscrew = 1.2 × 108 cm−2; Dedge = 1.6 × 109 cm−2) were obtained for the sample annealed at 1050 °C. Notably, both tilt and twist angles exhibited a minimum at 1050 °C (tilt = 252 arcsecs, and twist = 558 arcsecs), indicating improved crystal quality at this specific temperature. Photoluminescence (PL) spectroscopy further complemented the structural analysis. The intensity and broadening of the yellow band (YL) in the PL spectra progressively increased with the increasing annealing temperature, suggesting the presence of additional defect states. The near band edge PL emission (3.35 and 3.41 eV) variation upon thermal annealing was correlated with the mosaic structure evolution.

Influence of the external N and P inputs on nutrients in the coastal area of Xiamen, China

Environmental context External nutrients giving rise to critical ecological issues of the coastal seawater. We investigated the nearshore nutrient concentrations and their sources in Xiamen Bay during 2013–18. Our results could provide theoretical support for controlling nearshore nutrient pollution. Rationale External nutrients greatly increase the critical ecological risks of the coastal seawater. Therefore, it is important to understand the sources and variation characteristics of nitrogen (N) and phosphorus (P) in the coastal area. Methodology The dissolved inorganic nitrogen (DIN) and phosphate (PO4–P) in coastal Xiamen were monitored from 2013 to 2018. The input of nitrogen from runoff in the coastal Xiamen was calculated from the runoff flow amount collected by Xiamen Marine and Fisheries Bureau. Atmospheric dry deposition of DIN was simulated using Williams model to analyse the potential sources of nutrients in the coastal Xiamen. Results High DIN and PO4–P levels occurred in the inner bay and decreased dramatically outside Xiamen Bay. The lowest values of DIN and PO4–P were observed in summer, which is consistent with the temporal variation in nutrient inputs from the surface runoff and atmospheric deposition. The nutrient input of Jiulong River is the main source of eutrophication for Xiamen Bay, providing more than 4 × 104 tonnes (Mg) of N input per year. The atmospheric N dry deposition provided more than 2.2 × 103 Mg of DIN input per year, which accounts for ~3.4–6.3% of the Jiulong River DIN input in the coastal Xiamen. Discussion The ratio of atmospheric nitrogen deposition to nitrogen enrichment from Jiulong River varied from 0.21 to 0.40, indicating that atmospheric nitrogen deposition was an important contributor to the coastal nutrient in Xiamen. This study provides an insight into the major sources of N and P and highlights the importance of atmospheric nitrogen deposition to the DIN in the coastal city Xiamen.

Terrestrial nanoparticles and geospatial optics: Implications for environmental impact from anthropogenic contaminants in the Caribbean region.

Atmospheric contaminants from natural processes and anthropogenic activities pose a major problem to the environment. Here we analyze the dynamics of atmospheric and terrestrial contaminant concentrations in sediments containing chemical elements, such as nanoparticles (NPs) and ultrafine particles in hydrological sources of the Caribbean region of Colombia. Terrestrial sediments were collected from 2022 to 2024, and quantified for major chemical elements in the form of NPs and ultrafine particles in runoff receiving areas along the banks of Colombia's Ciénaga Grande in Santa Marta Bay, on the Isla de Salamanca. Additionally, atmospheric carbon monoxide (CO) and nitrogen dioxide (NO2) levels were detected using TROPOMI, coupled with the Sentinel-5P satellite, from 2019 to 2024. Sampling was performed during both summer and winter, focusing on the Sierra Nevada de Santa Marta National Park, Isla de Salamanca, and the cities of Santa Marta and Barranquilla. Sediment samples were collected from 25 fixed sites on Isla de Salamanca and analyzed in the laboratory. The CO and NO2 concentrations were detected at 122 "collection points," with a spatial resolution of 7km×3.5km, an average normalization of 0.83μg/mg, and a maximum error of 6.62%. The results revealed abundant Fe particles containing Cr, Ti, Zn, and Zr (1-2.5μm in size), with nanohematite (iron oxide) particles containing C, As, and S detected via EDS. The CO concentrations peaked in Barranquilla and Santa Marta (up to 0.042mol/m2), while NO2 concentrations reached 2.4×10-5 mol/m2, similar to the levels in Sierra Nevada de Santa Marta National Park and Ciénaga Grande de Santa Marta. These findings highlight the impact of forest fires on air quality in the region and support the development of new public policies to mitigate pollution and to protect ecosystems in this ecologically relevant area.

AlN/FeNi Microwave-Attenuating Ceramics with High-Efficiency Thermal Conductivity and Microwave Absorption.

The integration, miniaturization, and high frequency of microwave vacuum electronics put forward higher requirements for heat-conducting and wave-absorbing integrated materials. However, these materials must balance the dispersion and isolation of wave-absorbing components to optimize absorption while maintaining the continuity of thermal conductivity pathways with low defect rates and minimal interfaces. This presents a significant challenge in achieving both high thermal conductivity and efficient wave absorption simultaneously. Here, AlN/FeNi microwave-attenuating ceramics were synthesized via non-pressure sintering in a nitrogen atmosphere. The influence of FeNi content (0-20 wt%) on the density, phase composition, microstructure, microwave-absorption properties and thermal conductivity of the composites was investigated. AlN/FeNi composites consist primarily of an AlN phase with FeNi0.0578, Fe, AlYO3, and Al5Y3O12 as secondary phases, and the microstructure is uniform and dense. As the FeNi content rises from 0 to 20 wt%, the density of the composites sintered at 1800 °C × 2 h increases from 3.3 to 3.7 g/cm3. Their X-band (2-18 GHz) dielectric constant goes up from 6.5 to 8.5, the dielectric loss factor rises from 0.1 to 0.9, and thermal conductivity diminishes from 130 to 123 W/m·K. Upon reaching an FeNi content of 20 wt%, the composite achieves a minimum reflection loss of -39.1 dB at 9.5 GHz, with over 90% absorption across an effective absorption bandwidth covering 2.5 GHz. It exhibits excellent impedance matching, electromagnetic wave-attenuation properties, a relative density of 98.6%, and a thermal conductivity of 123 W m-1 K-1. The prepared AlN/FeNi composites, with integrated outstanding microwave-absorption capabilities and thermal conductivity, holds great promise for applications in 5G communications, aerospace, and artificial intelligence.

Microwave-Assisted Reduction of Graphene Oxide to Reduced Graphene Oxide

Green chemistry seeks to find alternative synthesis routes that are less harsh to living organisms and the environment. In this communication, a microwave-assisted hydrothermal technique and a thermal annealing method were used in the reduction of graphene oxide (GO) to make reduced GO (rGO). Graphite powder was oxidised using the Improved Hummers’ method, exfoliated, and freeze-dried. Thereafter, an aqueous suspension of GO was reduced under microwave (MW) irradiation for 10 min at 600 W with and without the help of a reducing agent (hydrazine hydrate). Thermal annealing reduction was also conducted under a nitrogen atmosphere at 300 °C for 1 h. Prepared samples were analysed using Raman laser spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), the Brunauer–Emmett–Teller (BET) method, and X-ray photoelectron spectroscopy (XPS). A successful reduction in the GO functional groups between the sheets was established using XRD. In the Raman analysis, the ratio of the intensity of the D and G band (ID/IG) in graphene sheets assisted in assessing the quality of the graphene films. An estimation of the number of structural defects was calculated using the ID/IG ratio. The Raman analysis showed an increase in the ID/IG ratio after both oxidation and reduction processes. The defect densities of both MW-treated samples were comparable while an increased defect density was evident in the thermally annealed sample. TEM micrographs confirmed the sheet-like morphology of the samples. The rGO sheets obtained from the MW-treated method appeared to be smaller when compared to the rGO ones obtained by thermal treatment. It was also evident from XRD analysis that thermal treatment promoted the coalition of graphitic layers, such that the estimated number of layers was larger than that of GO. The elemental analysis showed that the C/O ratio of GO increased from 2 to 7.8 after MW hydrazine reduction.

Aluminum and Inorganic Natural Pigment Colored Composites by Powder Metallurgy Forming

Aluminum powder, along with other powders such as steel or stainless steel, is extensively used in powder metallurgy (PM) to produce complex samples with irregular geometric shapes. PM enables the incorporation of fillers to modify the physical, mechanical, or wear properties of aluminum without melting, thereby preventing phase segregation. The novelty of this work lies in the use of inorganic natural pigments (INPs). The primary goal of this study is to produce colored aluminum samples via PM without compromising their mechanical properties. INPs are first characterized to select those with the highest heat resistance. The composites are fabricated with different pigments (10 wt%), formed through uniaxial compaction at 500 MPa, and sintered in a nitrogen atmosphere at 610 °C for 30 min. Density, color, bending strength, and wear are evaluated to identify the most suitable pigment for gas kitchen burners. Mars red, Cobalt blue, and Chrome green pigments provide the best coloration. Dimensional variation is generally less than 1%. The pigments increase the material’s brittleness by 41% to 77%, resulting in a bending modulus increase of up to 160% and deformation reduction of up to 70%. In some cases, intermetallic compounds improve bending strength, as in Al–Chrome green, by 30%. Al–Chrome green exhibits wear resistance comparable to aluminum, with a 40% lower friction coefficient. X-ray diffraction and SEM-EDX confirm AlCr and AlCo intermetallic particles. Thermal stability is verified after 160 heating and cooling cycles without significant material degradation.

Optical properties of unoxidized and oxidized titanium nitride thin films

This study reports a pulsed laser deposition-assisted synthesis of highly metallic titanium nitride (TiN) and a series of semiconducting titanium oxynitride (TiNxOy) compounds in thin film form with tunable plasmonic properties by carefully altering the nitrogen (N)-oxygen (O) ratio. The N/O ratio was controlled from 0.3 (highest oxygen doping of TiN) to ~ 1.0 (no oxygen doping of TiN) by growing the TiN films under nitrogen pressures of 50, 35, and 10 mTorr and high vacuum conditions of 2 × 10−6 Torr with no external gas introduced. The presence of nitrogen in the deposition chamber during the film growth affects the gas phase oxidation of TiN to TiNxOy by increasing the mean free path-dependent N and O inter-collisions per second by two to three orders of magnitudes. The evidence of increased oxidation of TiN to TiNxOy with an increase in nitrogen deposition pressure was obtained using X-ray photoelectron spectroscopy analysis. While the TiN samples deposited in high vacuum conditions had the highest reflectance, TiNxOy thin films were also found to possess high reflectance at low frequency with a well-defined edge around 20,000 cm−1. Furthermore, the vacuum-deposited TiN samples showed a large negative dielectric constant of -330 and the largest frequency of zero-crossing at 25,000 cm−1; the TiNxOy samples deposited in the presence of nitrogen ambient also showed promising plasmonic applications at the near-mid infrared range. A comparison of the dielectric constant and loss function data of this research with the literature values for noble metals seems to indicate that TiN and TiNxOy have the potential to replace gold and silver in the visible and near-infrared spectral regions.

The impact of air pollution control measures and the COVID-19 pandemic on photosynthesis in urban trees

Phytotoxic air pollutants such as atmospheric nitrogen dioxide (NO2) are among the major stresses affecting tree photosynthesis in urban areas. We clarified the relationship between NO2 concentrations and photosynthetic function for three major urban trees, Prunus × yedoensis, Rhododendron pulchrum, and Ginkgo biloba, planted in Kyoto and surrounding cities, combining our published data and new data collected from 2020 to 2023. High NO2 increased long-term water use efficiency for all species. High NO2 decreased photosynthesis in P. yedoensis and R. pulchrum, while for G. biloba, NO2 imposed little effect on photosynthesis. We then focused on the decrease in NO2 due to (1) air pollution control measures from 2005 to 2023 and (2) the economic recession caused by the COVID-19 pandemic, and examined whether these factors improved photosynthesis in urban trees. The historic decrease in NO2 improved leaf photosynthesis for P. yedoensis and R. pulchrum, while the COVID-19 pandemic reduced NO2 by only 0.3 ppb and did not further improve photosynthesis in these tree species. This report shows that air pollution control measures improved photosynthesis in urban trees over several years in Japan, and is valuable because it demonstrates that air pollution control measures can increase CO2 uptake by urban trees.

Comprehensive Experimental Studies on Smoldering Characteristics of Forest Soil from pinus sylvestris Vegetation

ABSTRACTSmoldering combustion, often linked with forest fires in coniferous forests, pose significant health and environmental risks, particularly in densely populated countries like Germany, where these fires commonly occur in wildland–urban interface (WUI) areas. This study investigates the combustion characteristics of Pinus sylvestris soil, focusing on the underlying processes and thermal behavior. The aim is to provide a comprehensive analysis of smoldering combustion in pine forest soil, with a specific focus on fire‐exposed soil horizons. The research integrates soil characterization, elemental analysis, heat of combustion determination, and thermogravimetric analysis (TGA) of pine soil fractions ranging from < 0.063 to > 4 mm, conducted under both air and nitrogen atmospheres. The derivative thermogravimetry (DTG) curves reveal that the fastest mass loss occurs during pyrolysis, with peak temperatures between 240°C and 280°C. Activation energies (Ea) were calculated using the Kissinger–Akahira–Sunose (KAS) and Flynn–Wall–Ozawa (FWO) methods. The highest activation energies were observed between conversion rates of 0.2 and 0.4. Activation energies at peak temperatures for all fractions were determined using the Kissinger method. Residue analysis reveals significant variations in organic content, ranging from 22.6% to 92.7%. The findings demonstrate that German‐typical pine soil is prone to smoldering combustion, highlighting processes determined as preheating, drying, pyrolysis, and oxidation. As part of the German Pilot of the EUs TREEADS project, this study provides essential data for numerical simulations, emphasizing the need to consider both physical and chemical properties of soil fractions to mitigate the impact of smoldering fires in pine forest ecosystems.