Soluble Carbon Research Articles

Nutrient loading weakens seagrass blue carbon potential by stimulating seagrass detritus carbon emission

Coastal nutrient loading has been linked to a decline in the capacity of seagrass ecosystems to sequester carbon (‘blue carbon’); however, the mechanisms are unclear. Here we investigated how nutrient loading can affect the contribution that seagrass plant material makes to blue carbon stocks by investigating plant quality-decomposition dynamics. Specifically, we used a combination of laboratory and field experiments to account for various changes in biogeochemical cycling from seagrass meadows, ranging from changes in leaf quality to CO2 fluxes. It was found that nutrient loading increased the ‘labile’ content of seagrass (i.e. increased levels of leaf nitrogen, phosphorus and soluble organic carbon (amino acid and soluble sugar content), and at the same time decreased levels of ‘recalcitrant’ carbon (i.e. materials that are harder for microbes to break down, such hemicellulose, cellulose and lignin contents). Nutrient-enriched leaves decomposed ∼ 18 % faster than non-enriched leaves (i.e. greater biomass loss from nutrient-affected seagrass), resulting in ∼ 80 % more CO2 emissions from nutrient-enriched seagrass. We also found that seagrass that naturally contained high levels of labile carbon at the start of the experiment were affected to a greater degree (i.e. higher CO2 emissions) by nutrients addition than seagrass that had high proportions of recalcitrant carbon to begin with. Overall, these findings suggest that nutrient loading can weaken the capacity of seagrass ecosystems to act as blue carbon sinks through its effect on seagrass leaf decomposability.

Functional Diversity Accelerates the Decomposition of Litter Recalcitrant Carbon but Reduces the Decomposition of Labile Carbon in Subtropical Forests

The biodiversity of litter can regulate carbon and nutrient cycling during mixed decomposition. It is common knowledge that the decomposition rates of mixed litters frequently deviate from those predicted for these component litter species. However, the direction and magnitude of the nonadditive effects on the degradation of mixed litters remain difficult to predict. Previous studies have reported that the different carbon fractions of leaf litters responded to litter mixture differently, which may help to explain the ambiguous nonadditive effect of diversity on bulk litter decomposition. Therefore, we conducted decomposition experiments on 32 litter mixtures from seven common tree species to test the responses of different carbon fractions to litter diversity in subtropical forests. We found that the overall mass loss of the mixed litter was faster than that estimated from single species. The relative mixing effects (RMEs) of different carbon fractions exhibited different patterns to litter diversity and were driven by different aspects of litter functional dissimilarity. Soluble carbon fractions decomposed more slowly than expected from single species, while lignin fractions decayed more quickly. Moreover, we found that the RMEs of bulk litter decomposition may be determined by the lignin fraction decomposition. Our findings further support that distinguishing the response of different carbon fractions to litter diversity is important for elucidating the nonadditive effects of total litter decomposition.

Effects of combined PS-Pb pollution on the calcification of Paphia undulata: Coexistence of antagonistic and synergistic effects

Similar to respiration, shellfish function as a carbon source because they release carbon dioxide during calcification which uses soluble inorganic carbon in seawater to form biological calcium deposits, such as shells, which is important for shellfish survival. Almost all filter feeding shellfish feed mainly on phytoplankton, which are the most dominant primary producers in marine ecosystems. Microplastics and Pb generally coexist in the habitat of Paphia undulata, and microplastics adsorb Pb. Both of these two matters negatively affect metabolism that affects calcification. Thus, it is speculated that the interaction between microplastics and Pb affects the calcification of P. undulata by affecting its metabolism. This hypothesis is related to the carbon cylce drived by filter feeding shellfish under combined pollution of microplastic and Pb. Nevertheless, related studies are extremely rare. To verify this hypothesis, P. undulata was exposed to PS-Pb combined pollution for 96 h, during which microplastics and Pb were represented by polystyrene (PS) with a particle size of 5.0 µm and Pb (NO3)2, respectively. Ammonia excretion was affected by PS and the interaction of PS and Pb. Not the oxygen consumption but the ratio of O/N was affected by PS, Pb and their interaction. If the concentrations of PS and Pb were 50 and 6 μg/L, respectively; the ratio of O/N of P. undulata was higher than that under the other treatments. The calcification was influenced by Pb and the interaction of PS and Pb, e.g., as the concentrations of PS and Pb were 25 and 6 μg/L, respectively, the calcification rate of P. undulata was the lowest. Moreover, the calcification rate was positively correlated with the ratio of O/N, i.e., there was a correlation between the calcification rate and metabolic substrates. PS and Pb at low concentrations had a synergistic effect on calcification, while they tended to produce antagonism at high concentrations. All these facts mean that the effect of compound pollution on calcification is not a simple addition of the effects of the two pollutants that influence calcification by affecting metabolism, and the effects of the PS-Pb combined pollution on the carbon cycle in offshore areas should be reassessed.

Effect of Nutrient Management Practices on Carbon Pools Following 13 Year of Cropping with Soybean (Glycine max) Based Cropping Systems in Vertisol of Central India

Organic manure application has its significant impact on the soil health. Low organic matter in tropical soils is a major factor contributing to their poor productivity. Soil properties have been continuously influenced by the management practices and land uses, in which latter one has been, identified as profound influence on soil properties especially on soil organic carbon. A thirteen year experiment on soybean based cropping system in a vertisol of central india under organic farming was used for this investigation An investigation was carried out on “Soil organic carbon dynamics under long-term nutrient management in soybean based cropping system” at the Indian Institute of Soil Science, Bhopal on an on-going research project on organic farming. The effect of organic, integrated and inorganic nutrient management was assessed in three cropping systems viz. soybean (JS 335)-wheat (Malwa Shakti), soybean-mustard (Pusa Bold) and soybean-gram (JG 130) on aggregate size fractions, carbon content in aggregate as well as soil organic carbon pools dynamics on a split plot experimental design with three replications. The study relevant to dynamics of soil organic carbon pools revealed higher content of soil organic carbon, labile carbon, water soluble carbon, SMBC as well as dehydrogenase activity that varied between 1.04 and 0.86 percent; 440 and 538 mg kg-1, 52.97 and 70.43; 288 and 375 mg kg-1, 88 and 137 µg TPF g-1 soil d-1, respectively in surface 0-15 cm soil under organic nutrient management.

Quantitative hardness‐carbon content‐microstructure correlation in normalized plain carbon steel

AbstractComposition (carbon content) dependent critical structural evolution in correlation to hardness attained is judiciously investigated for plain carbon steel, the most widely used cost‐effective structural material, under normalizing treatment of industrial relevance involving non‐equilibrium still air cooling. The solid state phase transformation under non‐equilibrium still air cooling is conceived in terms of a logarithmic variation of eutectoid carbon content with the gross carbon content of steel in view of maintaining fixed maximum solubility of carbon in α‐iron with an assumption of the prevailing para‐equilibrium condition. Such a unique formulation for non‐equilibrium condition together with consideration of Hall–Petch type relationship and rule of mixture for two prime microconstituents (proeutectoid α‐ferrite and pearlite) finally results in a new mathematical relationship for chemical composition‐structure‐property correlation for the non‐equilibrium normalizing treatment readily practiced in industry. Indeed, a composition dependent structural refinement effect is established that is exemplified with the rise in hardness level in plain carbon steel under conventional normalizing treatment. Most importantly, the experimentally measured overall hardness values closely follow those obtained by the developed mathematical relationship, thereby meeting an ever‐needed requirement of direct determination of steel hardness of practical relevance from microstructural parameters.

Metrological traceable calibration of organic carbon and elemental carbon based on laboratory-generated reference materials

Carbonaceous aerosol, including organic carbon (OC) and elemental carbon (EC), has significant influence on human health, air quality and climate change. Accurate measurement of carbonaceous aerosol is essential to reduce the uncertainty of radiative forcing estimation and source apportionment. The accurate separation of OC and EC is controversial due to the charring of OC. Therefore, the development of reference materials (RM) for the validation of OC/EC separation is an important basis for further study. Previous RMs were mainly based on ambient air sampling, which could not provide traceability of OC and EC concentration. To develop traceable RMs with known OC/EC contents, our study applied an improved aerosol generation and mixing technique, providing uniform deposition of particles on quartz filters. To generate OC aerosol with similar pyrolytic property of ambient aerosol, both water soluble organic carbon (WSOC) and water insoluble organic carbon (WIOC) were used, and amorphous carbon was selected for EC surrogate. The RMs were analyzed using different protocols. The homogeneity within the filter was validated, reaching below 2%. The long-term stability of RMs has been validated with RSD ranged from 1.7%–3.2%. Good correlation was observed between nominal concentration of RMs with measured concentration by two protocols, while the difference of EC concentration was within 20%. The results indicated that the newly developed RMs were acceptable for the calibration of OC and EC, which could improve the accuracy of carbonaceous aerosol measurement. Moreover, the laboratory-generated EC-RMs could be suitable for the calibration of equivalent BC concentration by Aethalometers.

Colossal C130 Fullertubes: Soluble [5,5] C130-D5h(1) Pristine Molecules with 70 Nanotube Carbons and Two 30-Atom Hemifullerene End-caps.

We report the seminal experimental isolation and DFT characterization of pristine [5,5] C130-D5h(1) fullertubes. This achievement represents the largest soluble carbon molecule obtained in its pristine form. The [5,5] C130 species is the highest aspect ratio fullertube purified to date and now surpasses the recent gigantic [5,5] C120-D5d(1). In contrast to C90, C100, and C120 fullertubes, the longer C130-D5h has more nanotubular carbons (70) than end-cap fullerenyl atoms (60). Starting from 39,393 possible C130 isolated pentagon rule (IPR) structures and after analyzing polarizability, retention time, and UV-vis spectra, these three layers of data remarkably predict a single candidate isomer and fullertube, [5,5] C130-D5h(1). This structural assignment is augmented by atomic resolution STEM data showing distinctive and tubular "pill-like" structures with diameters and aspect ratios consistent with [5,5] C130-D5h(1) fullertubes. The high selectivity of the aminopropanol reaction with spheroidal fullerenes permits facile separation and removal of fullertubes from soot extracts. Experimental analyses (HPLC retention time, UV-vis, and STEM) were synergistically used (with polarizability and DFT property calculations) to down select and confirm the C130 fullertube structure. Achieving the isolation of a new [5,5] C130-D5h fullertube opens the door to application development and fundamental studies of electron confinement, fluorescence, and metallic character for a fullertube series of molecules with systematic tubular elongation. This [5,5] fullertube family also invites comparative studies with single-walled carbon nanotubes (SWCNTs), nanohorns (SWCNHs), and fullerenes.

Theoretical and experimental analysis of CO2 capture into 1,5-diamino-2-methyl-pentane/n-propanol non-aqueous absorbent regulated by ethylene glycol

The non-aqueous amine solvents for CO2 capture gaine an advantage in energy-saving potential, but with a sharp increase viscosity after saturated absorption would easily cause problems such as equipment scaling and pipe blockage. In the present work, the ethylene glycol (EG) was used as co-solvent and activator to regulate the non-aqueous absorbent of 1,5-diamino-2-methyl-pentane (DA2MP) and n-propanol (PrOH) for CO2 capture. The absorption loading of the mixture solution was 1.13 mol·mol−1 when the mass concentration of DA2MP was 25 wt% and the volume ratio of PrOH to EG was 8:2. By activated by EG, the viscosity of the saturated solution was only 9.05 mPa·s, which changed from viscous precipitation to clarify liquid compared with that of DA2MP/PrOH. The absorbent maintained 90.30% of its initial CO2 absorption loading after 10th cycle regeneration under 393.15 K for 60 min. According to the quantum chemical calculations and experimental results, the reaction and regulation mechanism of CO2 capture into DA2MP/PrOH/EG was clarified. In DA2MP-PrOH solution, CO2 firstly reacted with DA2MP to form carbamate, and them the product further reacted with PrOH to form alkyl carbonates, which was viscous and insoluble due to the high intermolecular force between the CO2 products. After adding appropriate amount of EG, the solubility of insoluble products in solvent was increased through weakening the intermolecular interaction of products and enhancing the intermolecular interaction between products and solvents, which further converted them into soluble alkyl carbonate and realized viscosity reduction. The regeneration heat duty of DA2MP/PrOH/EG solution was estimated as 1.58 GJ·ton−1 CO2, which was 29.5% and 58.42% less than that of DA2MP/PrOH and bench mark MEA solution, respectively, indicating a alternative candidate for CO2 capture.

Spatial lithological heterogeneity of the deep-sea sediments and its controlling factors in the northern West Caroline Basin, tropical West Pacific

Uncovering the spatial distribution of deep-sea sediment lithologies is crucial for the research on earth system science and the exploration of critical mineral resources. The conventional global deep-sea sediment lithology distribution maps showed that the lithologies were relatively uniform in the global major ocean basins. Furthermore, it was deemed that the deep-sea sediment lithologies were related to the productivity of surface seawater. However, later studies have illustrated that the distribution of deep-sea sediment lithologies exhibited greater variability and heterogeneity than conventional maps and that water depth played a more important role in controlling deep-sea sediment lithologies than productivity. In addition, few studies have focused on the relationship between the heterogeneous deep-sea sediment lithologies and the diverse seafloor topography in the West Pacific. In this study, we provide a high-resolution spatial distribution map of deep-sea sediment lithologies by systematic descriptions of 112 surface samples in the northern West Caroline Basin, tropical West Pacific, with a large range of water depth and a diverse seafloor topography to verify the previous prediction of sediment lithology distribution. Subsequently, based on the results of the determinations of carbonate and biogenic silica contents, the sediment redox-potential tests, and the calculations of multiple variables, we carried out quantitative studies and correlation analyses for these variables to reveal the relative contribution of different factors to the lithological heterogeneity in the northern West Caroline Basin. Our results show that the actual deep-sea sediments have greater heterogeneity in terms of lithological classes and distribution patterns than the earlier predicted lithology maps. Furthermore, our analyses reveal that water depth and seafloor topography are the more important controlling factors on the deep-sea sediment lithology to some extent than productivity and that water depth and topography may exert different effects on the different sediment components. For the calcareous component, water depth is the main controlling factor due to the increased solubility of carbonate with water depth. Carbonate materials can dilute other components in the waters above the carbonate compensation depth, which is around 4500 m below the sea surface in the study area. Meanwhile, the siliceous component may be enriched in the unique negative seafloor topography of the trench and trough with the specific lateral transport mechanism and the redox environment. These findings imply a more complicated actual deep-sea sediment lithology distribution than previously thought given that various water depths and diverse topography in the global oceans, which are significant for understanding deep-sea sedimentary processes and improving the models for predicting global sediment lithology in the deep sea.

Upcycling plastic polymers into single-walled carbon nanotubes from a magnesia supported iron catalyst

Plastic waste has posed an ever-growing environmental threat to the United Nations’ sustainable development goals. Converting plastic polymers into high value chemicals like carbon nanotubes is a promising approach for recycling without carbon dioxide emission. Using a two-stage pyrolysis-catalytic reactor, we herein report the transformation of five types of plastic polymers into high-quality single-walled carbon nanotubes (SWNTs) with the assistance of a rationally designed heterogeneous catalyst, i.e., an iron metal catalyst supported by porous magnesia. Because of the high metal dispersion and the large carbon solubility of the active component, the heterogeneous catalyst affords the formation of uniform metal particles which can sustain high carbon fluxes, resulting in the synthesis of high quality SWNTs. More importantly, the approach is also demonstrated with mixtures of plastic polymers. This work helps gain deep insights into the mechanisms of plastic polymer conversion to SWNTs, accelerating the progress toward a sustainable plastic economy.

Effect of Homogenization Treatment on Microstructure and Eutectic Precipitates in Ce‐Containing 15Cr–22Ni–1Nb Austenitic Heat‐Resistant Stainless Steel

The effects of homogenization temperature and time on microstructure and eutectic precipitates in Ce‐containing heat‐resistant stainless steel are studied. The increase in the homogenization temperature and time promotes the diffusion of alloying elements and the transition from dendrite structure to austenitic grain. Laves phase particles are fully dissolved after the homogenization of the ingots regardless of the cerium contents and homogenization temperature and time, except for the case of the homogenization at 1130 °C for 4 h. Honeycomb Laves phases gradually dissolve and become clusters of small blocky during homogenization treatment. The amount of eutectic NbC dissolved into the matrix is increased with the increase in the homogenization temperature and time. The solubility of niobium and carbon in austenite is increased with increasing the cerium content, which is beneficial to the dissolution of eutectic NbC. The distribution homogeneity of alloying elements in the austenitic matrix is increased with the increase in the cerium content. The homogenization temperature for reaching full diffusion of alloying elements into austenitic matrix is decreased with increasing the homogenization time. The decrease in the secondary dendrite arm spacing by cerium addition is favorable to the homogenization of alloying elements during homogenization treatment.

Development of a cell-based quaternary system to unveil the effect of pectic polysaccharides on oral astringency

Phenolic compounds are responsible for food unpleasant taste properties, including astringency, due to their ability to interact with salivary proteins and oral constituents. Astringency is a crucial attribute for consumer's acceptability. To fulfill the demand for both healthy and tasty food, polysaccharides raise as a good alternative to modulate astringency. In this work, a cell-based quaternary system was developed to evaluate the ability of polysaccharides to reduce the interaction between two classes of hydrolysable tannins – gallotannins (tannic acid) and ellagitannins (punicalagin) – and oral constituents (cells, salivary proteins and mucosal pellicle). So, pectic polysaccharide fractions isolated from grape skins, imidazole soluble polysaccharides (ISP) and carbonate soluble polysaccharides (CSP), as well as a commercial pectin, were tested.Results showed that the polysaccharide's effect depends on the structural features of the molecules involved. CSP fraction and pectin were the most effective, reducing the interactions between both tannins and the oral constituents, mainly in the complete oral model. The highest uronic acid content and the presence of methyl esterified groups could explain their high reduction ability. For tannic acid, the reduction effect increased along with the galloylation degree, while the interaction of β-punicalagin with the oral constituents was practically inhibited at 3.0 mg.mL−1.

Sintering window and sintering mechanism for diamond

High performance sintered diamond tools, such as those applied to wire drawing and rock drilling, represent a considerable advance in hard materials technology. A dense diamond-metal composite is produced using liquid phase sintering. With a cemented carbide substrate, a cobalt-rich liquid infiltrates between the diamond grains at temperatures near 1400 °C. For small diamond particles (nominally below 20 μm), a combination of high pressure (5 GPa or more) and high temperature (1400 °C or more) gives full density in minutes. A sintering window is defined by the pressure and temperature combination that avoids graphitization while ensuring cobalt melt infiltration. The sintering mechanism is carbon transport by dissolution of graphite from low pressure regions away from grain contacts with precipitation of diamond at grain contacts under high pressure. Sinter bonds preferentially nucleate at surface defects, such as screw dislocation spirals. Bonding rates depend on particle size, carbon solubility, temperature, pressure, and hold time. Calculations are shown for interface reaction site limited growth kinetics.

Simple and Complex Substrates (Sugar, Acetate and Milk Whey) for In Situ Bioremediation of Groundwater with Nitrate and Actinide Contamination

The complex contamination of groundwater near radioactive waste repositories by nitrates and actinides is a common problem for many nuclear fuel cycle facilities. One of the effective methods to remove nitrates and reduce actinide migration activity is bioremediation through the activation of native microbial communities by soluble electron donors and carbon sources. This work evaluated the effectiveness of using simple and complex electron donors to remove nitrate in the microbial community in an aquifer near the B2 storage of the Siberian Chemical Combine (Seversk, Siberia). The addition of sugar and milk whey led to the maximum efficiency of nitrate-ion removal and a decrease in the redox potential of the system, creating optimal conditions for the immobilization of actinide. Special attention was paid to the behavior of uranium, plutonium, neptunium, and americium under conditions simulating groundwater when sugar, acetate, and milk whey were added and when microbial metabolic products were formed. Neither microbial metabolites nor organic solutions were found to have a significant effect on the leaching of neptunium. At the same time, for plutonium, a decrease in yield was observed when rocks were treated with organic solutions were compared to groundwater treatment without them. Plutonium leaching is significantly affected by rock composition. In rocks with a low clay fraction content, its yield can reach 40%. At the same time, microbial metabolites can increase americium (Am) desorption from rocks with a low clay fraction content. Additionally, particle size analysis was performed using a step-by-step filtration approach, aiming to evaluate the risks that are associated with colloidal phase formation. It was shown that microbiological stimulation resulted in particle enlargement, substantially diminishing the presence of actinides in the form of dissolved or sub-50 nm nanoparticles. This outcome significantly reduced the potential for colloidal and pseudocolloidal transfer, thereby lowering associated risks.

Illuminating plant–microbe interaction: How photoperiod affects rhizosphere and pollutant removal in constructed wetland?

Rhizosphere is a crucial area in comprehending the interaction between plants and microorganisms in constructed wetlands (CWs). However, influence of photoperiod, a key factor that regulates photosynthesis and rhizosphere microbial activity, remains largely unknown. This study investigated the effect of photoperiod (9, 12, 15 h/day) on pollutant removal and underlying mechanisms. Results showed that 15-hour photoperiod treatment exhibited the highest removal efficiencies for COD (87.26%), TN (63.32%), and NO3–-N (97.79%). This treatment enhanced photosynthetic pigmentation and root activity, which increased transport of oxygen and soluble organic carbon to rhizosphere, thus promoting microbial nitrification and denitrification. Microbial community analysis revealed a more stable co-occurrence network due to increased complexity and aggregation in the 15-hour photoperiod treatment. Phaselicystis was identified as a key connector, which was responsible for transferring necessary carbon sources, ATP, and electron donors that supported and optimized nitrogen metabolism in the CWs. Structural equation model analysis emphasized the importance of plant–microbe interactions in pollutant removal through increased substance, information, and energy exchange. These findings offer valuable insights for CWs design and operation in various latitudes and rural areas for small-scale decentralized systems.

Solubility of Cesium Carbonate in Five Pure Solvents and Two Binary Solvents from 278.15 to 323.15 K

Solubility of Cesium Carbonate in Five Pure Solvents and Two Binary Solvents from 278.15 to 323.15 K

Differences in the solubility of CaCO3 from blood clam shells and Ca(OH)2 as a candidate pulp capping material

Background: Calcium hydroxide (Ca(OH)2) is the gold standar in pulp capping treatment because the biocompatibility and capability to stimulate hard tissue formation and also antibacterial effect. However, this compound has the disadvantage of being easily soluble in saliva which will increase the risk of leakage in the cavity. Another alternative pulp capping material is calcium carbonate from blood clam shells. Blood clam shells contain 98% CaCO3, CaCO3 has low solubility and is difficult to dissolve in water due to the large ions on Ca2+ and CO32- so that the attractive force between these ions is very strong and finally H2O is not able to break down the CaCO3 compound to be dissolved. Purpose: Explained the differences in the solubility of calcium carbonate from blood clam shells and calcium hydroxide as candidates pulp capping materials. Methods: This research is a laboratory experimental study with a pretest-posttest control group design method. The samples consisted of 12 pieces of Ca(OH)2 and CaCO3 then divided into 2 groups and given treatment. Group 1 CaCO3 immersed in 1 day, group 2 Ca(OH)2 immersed in 1 day, group 3 CaCO3 immersed in 7 days, and group 4 Ca(OH)2 immersed in 7 days. Solubility is calculated according to the solubility formula. Data testing with Anova-Welch. Results: There was a significanly difference in the solubility rate between the CaCO3 dan Ca(OH)2 groups immersed for 1 day and 7 days on the Anova-Welch results (p<0.05). Conclusion: The solubility of CaCO3 in blood clam shells is lower than the solubility in Ca(OH)2.)

Physical properties and magnetic resonance imaging of the Australian green plum (Buchanania obovata) through maturity and ripening and across locations

The green plum (Buchanania obovata) is a small fruit eaten by Aboriginal people in the northern parts of Australia. The trees grow in remote locations and the fruit has received very little study by Western food science. This study aims to profile and analyse physical characteristics of the green plums as they grow and ripen across multiple locations and harvests. Fruit from four locations, five maturity stages and two harvests were characterised using standard physical measurements, magnetic resonance imaging (MRI), moisture content, titratable acidity, pH, total soluble solids, and ethylene, oxygen and carbon dioxide gas analysis. Results of the physical measurements were analysed with multivariate data analysis using principal component analysis (PCA). This study confirms that the five-stage maturity index has accurately classified the maturity stages in the green plums, how maturity stages can be described with physical parameters and the specific changes that occur between each stage of the maturity process. This study has concluded that green plum is a climacteric fruit and suggest that further studies exploring these characteristics could increase its commercial potential. This report provides valuable characteristics of the green plums as potential products for Indigenous agribusinesses and the food industry.

Emission of water soluble brown carbon from different combustion sources: optical properties and functional group characterisation

Brown carbon (BrC) has a large impact on the Earth’s radiative balance. This study examined BrC’s optical characteristics, chemical functional groups, and total organic carbon (TOC) in deposited particulate matter from combustion of biomass, fossil fuels, and mosquito coil. A UV–vis spectrophotometer was used to assess BrC’s optical properties, a TOC analyzer was used to quantify TOC, and attenuated total reflection-fourier transform infrared spectroscopy (ATR-FTIR) was used to identify functional group. The light absorption properties (absorption coefficient (babs-BrC), mass absorption efficiency (MAE365), absorption angstrom exponent (AAE), and refractive index (kabs-BrC)) were determined. Among biomasses, wheat straw exhibited the greatest value of babs-BrC (27.26 × 103 ± 4.09 × 103 Mm−1) whereas maize straw had the lowest value of babs-BrC (7.38 × 103 ± 1.11 × 103 Mm−1). A higher light absorption coefficient at 365 nm suggested that chromophores contributed more to the process. AAE followed this sequence - mosquito coil (5.46 ± 0.82) > biomass (5.13 ± 1.45) > fossil fuels (2.85 ± 0.32). The highest value of MAE365 (0.99 ± 0.15 m2 gC−1) and kabs-BrC (0.028 ± 0.004) was obtained in wheat straw, whereas the lowest value of MAE365 (0.07 ± 0.011 m2 gC−1) and kabs-BrC (0.002) was identified in octane. Biomasses samples showed a strong peak at ∼850, ∼1368, ∼1370, ∼1306, and near 1640 cm−1, indicating that the major component of BrC was organic nitrate R-ONO2 which is responsible to increase the light absorption properties. It also contains complex heterocyclic aromatic ring compounds, carbonyl group (C=O), and nitrogen-containing groups such as −NO 2, C≡N. The projected substantial contribution of BrC to overall light absorption is one illustration of the probable climatic effect of biomasses and fossil fuel burning in Southeast Asian region.

Recent Understanding in the Chemical Vapor Deposition of Multilayer Graphene: Controlling Uniformity, Thickness, and Stacking Configuration.

Multilayer graphene has attracted significant attention because its physical properties can be tuned by stacking its layers in a particular configuration. To apply the intriguing properties of multilayer graphene in various optoelectronic or spintronic devices, it is essential to develop a synthetic method that enables the control of the stacking configuration. This review article presents the recent progress in the synthesis of multilayer graphene by chemical vapor deposition (CVD). First, we discuss the CVD of multilayer graphene, utilizing the precipitation or segregation of carbon atoms from metal catalysts with high carbon solubility. Subsequently, we present novel CVD approaches to yield uniform and thickness-controlled multilayer graphene, which goes beyond the conventional precipitation or segregation methods. Finally, we introduce the latest studies on the control of stacking configurations in bilayer graphene during CVD processes.