High Yield Carbon Research Articles

Target-oriented synthesis of high synthetic yield carbon dots by waxberry for optical dual-mode and smartphone imaging detection of morin

• The bio-friendly N-CDs are obtained from waxberry with a high yield of 71%. • A ratiometric fluorescent sensing platform is established for morin detection. • Excellent sensitivity of N-CDs for morin is validated with a LOD of 56 nM. • The visual and quantitative detection of smartphone sensor is realized. Recently, the use of natural products for the synthesis of carbon dots (CDs) has received much attention due to its peculiar characteristics. Herewith, the novelty of our present work is the green, large-scale production of fluorescent nitrogen doped CDs (N-CDs) synthesized from the waxberry by simple hydrothermal treatment. The current method delivers a high yield of 71% and the N-CDs exhibits 484 nm emission wavelength for detection of morin. Meanwhile, the increase of morin concentration can cause significant color changes. Hence, an optical dual-mode sensor for morin detection in the range of 0–35 μM with a limit of detection (LOD) of 56 nM and a smartphone imaging method are developed, which will broaden the application range of N-CDs in on-site detection.

High quantum yield carbon quantum dots as selective fluorescent turn-off probes for dual detection of Fe2+/Fe3+ ions

Carbon quantum dots (CQDs) are fluorescent nanoparticles that have great potential for use as nontoxic fluorescent probes. However, synthesizing CQDs with high photoluminescence quantum yield (QY) in a rapid and facile way from commonly available and low-cost reagents is still challenging. In this work, Tween®80 was used as a surface passivation agent along with citric acid/urea in a one-step microwave procedure to make extremely blue luminous nitrogen doped CQDs. When excited at 350 nm, these CQDs had a fluorescent quantum yield of 75.5 %. The significant high quantum yield and stability of these CQDs are attributed to the high aromatic sp2 domain size within the CQD core and improved carbon and oxygen functional groups at the CQDs surface. We employed the CQDs as a fluorescent probe to detect Fe2+ and Fe3+ ions and could establish a linear relationship between photoluminescence quenching efficiency (F0-F/F0) and ion concentration with a detection limit of 6.5 µM and 2.5 µM for Fe2+ and Fe3+, respectively. Our studies suggest that the highly selective detection of iron ions is a result of partial transfers of excited electrons from the CQDs to the d orbital of the iron ions, instead of contributing to radiative relaxation that induces photoluminescence quenching of the CQDs. Other reported carbon dots for this application have a substantially lower quantum yield and only detect Fe3+ ions. Therefore, our CQDs have considerable benefits over similar probes. Subsequent research may adapt them to other areas due to the high quantum yield and stability.

Preceding crops changed greenhouse gases emission and carbon neutrality under maize-rice and double rice cropping systems

ABSTRACT Conversion from double rice cropping (RR) to maize-rice cropping (MR) have been occurring in recent years in Asia. However, effects on the environment by introducing maize into paddy still need more examination. The objective of this study was to assess differences in greenhouse gases emissions, carbon footprint and carbon neutrality between MR and RR cropping systems from 2016 to 2018. Results showed that the global warming potential (GWP) under MR cropping was 13.0 t CO2 eq ha−1, which was 20.0% higher than that of RR (10.8 t CO2 eq ha−1) due to its higher N2O emission. Although the GWP of MR increased, it significantly decreased carbon footprint by 17.3% in comparison with RR due to its higher gain yield. Simultaneously, MR had a substantial increase in net ecosystem economic efficiency by 62.5%. Nevertheless, carbon uptake was significantly higher in MR system, its carbon neutrality was lower than that of RR by 69.3% average. In conclusion, MR could be an effective sustainable cropping system with high yield and low carbon footprint in the subtropical regions. Considering the higher GWP of MR, further research is needed on appropriate agronomic practice to reduce carbon loss to realize higher carbon neutral potential.

High‐Yield Carbon Dots Interlayer for Ultra‐Stable Zinc Batteries

AbstractThe practical implementation of Zn metal anodes with high volumetric capacity is seriously plagued by the dendritic growth and accompanying interfacial parasitic reactions. Herein, high yield carbon dots (CDs) with abundant polar functional groups (CHO and CN), as a functional artificial interface layer, are rationally designed to optimize electrolyte/Zn interfaces with large‐scale viability. Of particular note, the quantum‐sized CDs with strong Zn affinity can effectively ameliorate the electric field distribution and ensure that more Zn2+ is adsorbed onto the whole electrode, which are beneficial for lowering the barrier of Zn2+ nucleation and inducing homogeneous Zn deposition, thus rendering a dendrite‐free Zn anode, as extensively confirmed by in situ optical microscope observation and finite element simulation. Meanwhile, the dense and insoluble coating layer with abundant polar functional groups is conducive to arousing the repulsion effect, which is good for shielding the active water and SO42−, thus eliminating the water‐mediated parasitic reactions and improving Zn2+ reaction kinetics. More importantly, the electrochemically stable CDs layer endows the Zn anode with a prolonged lifespan of 3000 h at 1 mA cm−2. This feasible and efficient fabrication of functional CDs layer opens a new avenue for stable dendrite‐free metal anodes.

Field greenhouse gas emission characteristics and carbon footprint of ratoon rice

It is of great significance to understand the effects of different rice cultivation methods in southeast China on greenhouse gas emission characteristics and carbon footprint of paddy fields during rice cultivation for rice sustainable production. In this study, the popular conventional rice 'Jiafuzhan' and hybrid rice 'Yongyou 2640' were used as materials to establish four rice cultivation patterns suitable for different ecological types in Fujian Province: 1) double-cropping system, early rice and late rice with Jiafuzhan (D-J); 2) early maturing ratooning system, first season rice and ratooning season rice with Jiafuzhan (R-J); 3) middle-maturing ratooning system, first season rice and ratooning season with Yongyou 2640 (R-Y); and 4) single cropping system with Yongyou 2640 (S-Y), which should be synchronized in heading time with the counterpart (the ratooning season rice). Greenhouse gas emissions from paddy soil were measured by the closed static black box observation method and the gas chromatography method, respectively. The total direct and indirect greenhouse gas emissions (carbon footprints) from different rice farming patterns were evaluated by using the life cycle analysis. The results showed that greenhouse gas emissions in different rice cropping systems were lower in the early growth stage, then decreased after reaching the peak at the booting stage, demonstrating a double peak curve in the whole growth stage, in which the first peak was higher in early season or first season than the second peak in the late season or ratooning season in the cropping patterns. Moreover, the total greenhouse gas emissions were significantly different among cropping systems. The global warming potential (GWP) of different cropping patterns was in order of R-Y>D-J>S-Y>R-J, while the annual greenhouse gas emission intensity (GHGI) was D-J>S-Y>R-Y>R-J. GWP and GHGI of the ratooning system decreased by 26.1% and 14.1%, respectively, compared with those of the double-cropping system. The same pattern was observed in the ratooning rice of Yongyou 2640, which were decreased by 74.3% and 56.7%, respectively, compared with the counterpart, Yongyou 2640 in a single-cropping system synchronized heading. Carbon footprint of rice per unit yield ranged from 0.38-1.08 kg CO2-eq.·kg-1 under the different cropping systems, of which the carbon footprint of rice per unit yield was the highest under the double cropping system compared with that under other cropping systems. The reverse was true in the case of carbon footprint of rice per unit yield under the ratooning system with Yongyou 2640. Additionally, the main source of carbon footprint of different rice cropping patterns was CH4, contributing 44.2%-71.5%, suggesting that rice ratooning system could significantly reduce global warming potential and carbon emission intensity of rice in comparison with other cropping patterns. Therefore, it is key to select rice varieties with high yield and low carbon emission and to establish the supporting scientific cultivation techniques for effective reduction of CH4 emission and carbon footprint of paddy fields and promotion of ratooning rice production.

High Temperature Composites From Renewable Resources: A Perspective on Current Technological Challenges for the Manufacturing of Non-Oil Based High Char Yield Matrices and Carbon Fibers

During last decades a plethora of high temperature materials have been developed to work as a Thermal Protection System (TPS). Carbon based materials such as graphite, which possesses low density, high heat capacity and high energy of vaporization, have been used as TPS material. However, graphite has relatively poor mechanical properties, but exhibits low resistance to the thermal shocks. Accordingly, to bypass the limitation of graphite, carbon fibers are typically introduced in a carbon matrix to produce Carbon/Carbon Composites (CCCs). Among the different families of TPS solutions, Polymeric Ablative Materials (PAMs), produced combining high char yield matrices - mainly phenolic resins - and Carbon Fibers (CFs) are used to manufacture Carbon/Phenolic Composites (CPCs) i.e. the most important class of fiber reinforced PAM. Carbon fibers are traditionally produced from Polyacrylonitrile (PAN), Rayon and Pitch. Some limited researches also aimed to use cyanate-esters, bismaleimides, benzoxazines matrices in combination with ex-PAN-CFs, ex-Rayon-CFs, and ex-Pitch-CFs. In our paper, after covering the science and technology of these state-of-the-art fiber reinforced TPS materials, a review of current challenges behind the manufacturing of new, high char yield matrices and carbon fibers derived from alternative precursors will be provided to the reader. In particular, the possibility to produce CFs from precursors different from PAN, Rayon and Pitch will be reported and similarly, the technology of non-oil based phenolics, bismaleimides, cyanate-esters and benzoxazines will be discussed. The effect of the use of nanosized fillers on these matrices will also be reported. More in detail, after a preliminary section in which the state of the art of technologies behind carbon/phenolic composites will be covered, a second part of this review paper will be focused on the most recent development related to non-oil based phenolics and biomass derived carbon fibers. Finally, an outlook focused on the maturity of the lab-scale protocols behind the researches at the base of these non-traditional raw materials from an industrial point of view will conclude this review paper.

Peat soil-derived silica doped porous graphitic carbon with high yield for high-performance all-solid-state symmetric supercapacitors

The cost-effective fabrication of lightweight, safe, and solid-state supercapacitors with excellent performance, such as high energy and power densities and long cycle life, has recently become a critical issue in next-generation energy storage systems. As a result, current research efforts are focused on developing high-performance advanced electrode materials with high capacitance and outstanding stability, and solid electrolytes that provide flexibility and safety. Herein, the Marsh clay (peat soil) derived silica doped high yield and porous graphitic carbon (MCC) produced by simple pyrolysis and PVA/KOH polymer gel electrolyte are used as innovative components of the all-solid-state symmetric supercapacitor. Various characterizations were used to study the phase, microstructural, thermal, morphological, porosity, surface area, and compositional examination of the materials. An all-solid-state symmetric supercapacitor device based on the MCC and PVA/KOH gel electrolyte is fabricated. The developed supercapacitor device delivers a maximum specific capacitance of 160 F/g (at a scan rate of 10 mV/s) and exhibits a high energy density of ~18 Wh/kg at a power density of ~312 W/kg, and displays low resistance and good cycling stability. Overall, the developed all-solid-state symmetric supercapacitor with the novel MCC and PVA/KOH gel electrolyte represents the potential for high-performance supercapacitors.

Chemically Accelerated Stabilization of a Cellulose-Lignin Precursor as a Route to High Yield Carbon Fiber Production.

The production of carbon fiber from bio-based or renewable resources has gained considerable attention in recent years with much of the focus upon cellulose, lignin, and cellulose-lignin composite precursor fibers. A critical step in optimizing the manufacture of carbon fiber is the stabilization process, through which the chemical and physical structure of the precursor fiber is transformed, allowing it to withstand very high temperatures. In this work, thermogravimetric analysis (TGA) is used to explore and optimize stabilization by simulating different stabilization profiles. Using this approach, we explore the influence of atmosphere (nitrogen or air), cellulose-lignin composition, and alternative catalysts on the carbon yield, efficiency, and rate of stabilization. Carbon dioxide and water vapor released during stabilization are analyzed by Fourier transform infrared (FTIR) spectroscopy, providing further information about the stabilization mechanism and the accelerating effect of oxygen and increased char yield (carbon content), especially for lignin. A range of different catalysts are evaluated for their ability to enhance the char yield, and a phosphorus-based flame retardant (H3PO4) proved to be the most effective; in fact, a doubling of the char yield was observed.

Carbon and nitrogen footprint of different peanut rotation systems in Hubei Province, China.

Clarifying carbon and nitrogen emissions of different peanut rotation planting system can provide an effective reference to achieve high yield, high efficiency, and low carbon and nitrogen emissions. Based on field surveys on agricultural inputs and field managements, we calculated the carbon footprint and nitrogen footprint of three planting modes (rape-peanut rotation, wheat-peanut rotation and peanut monoculture) in Huanggang, Hubei Province. The results showed that compared with wheat-peanut rotation, carbon emission per unit area of rape-peanut rotation decreased by 7.8%, carbon emission per unit net present value decreased by 36.9%, the nitrogen emission per unit area decreased by 12.5%, and nitrogen emission per unit net present value decreased by 41.9%. Compared with peanut monoculture, rape-peanut rotation reduced carbon and nitrogen emissions by 19.6% and 30.8%, respectively. The net income of rape-peanut rotation was 1.4 times as that of wheat-peanut rotation and 2.4 times as that of peanut monoculture. It is suggested that rape-peanut rotation could achieve the synergistic benefits of high yield and efficiency and low carbon and nitrogen emissions, which is conducive to the green, high quality, and high efficiency production of oil crops.

Copper-Catalyzed Decarboxylative Propargylic Alkylation of Enol Carbonates: Stereoselective Synthesis of Quaternary α-Amino Acids

A copper-catalyzed asymmetric decarboxylative propargylic alkylation of enol carbonates has been realized, allowing for the highly stereoselective formation of acyclic vicinal tri- and tetrasubstituted stereocenters. With this strategy, a series of optically active quaternary α-amino acid esters with an adjunct chiral tertiary propargylic moiety have been prepared from propargyl azlactone-enol carbonates in high yields and with good to excellent diastereo- and enantioselectivities. The success of this reaction exemplifies the high potential of the decarboxylative strategy to resolve unmet challenges present in traditional catalytic propargylic alkylation.

Optimisation of two-stage biomass gasification for hydrogen production via artificial neural network

A two-stage gasification has been proven as an effective and robust approach for converting low-valued and/or highly heterogeneous materials i.e. waste, into hydrogen and/or syngas due to its tight control and flexibility in operation. As the gas yield and gas properties depend upon materials and operating conditions, the interactions of operating conditions should not be ignored. However, these have not been able to fully capture experimentally. In this work, an artificial neural network model was developed and validated using experimental data to predict and optimise the gasification process thereby reducing time and costs in developing and testing. The model can predict accurately gas composition and yield corresponding to the variations at the output with a correlation R2 > 0.99. The developed neural network model was then applied for optimising operating conditions of the two-stage gasification for high carbon conversion, high hydrogen yield and low carbon dioxide in nitrogen and carbon dioxide environments. The predicted conditions were tested, and the results agreed well with experimental data. For example, at the optimum operating conditions (900˚C for the 1st stage and 1000 °C for the 2nd stage with a steam/carbon ratio of 3.8 in nitrogen and 5.7 in carbon dioxide environments), the gas yield, hydrogen and carbon dioxide were 96.2 wt%, 70 mol% and 16.4 mol% for nitrogen environment and 97.2 wt%, 66 mol% and 12 mol% for carbon dioxide environment.

Synthesis and characterization of catalytic CVD growth pristine and functionalized MWCNT

The catalyzed CVD method is considered significant for the production of low cost and high yield carbon nanostructures. In this study, multiwall carbon nanotubes (MWCNTs) were synthesized using a facile and efficient way with the modified CVD method, using Co nanoparticles as the metallic catalysis for MWCNT growth, in a distinct temperature range of 650–750 °C. The structural and magnetic properties of pristine and functionalized MWCNT (p-MWCNT and f-MWCNT) are investigated in the temperature range of 10–300 K. The phase structure of all MWCNT samples was analyzed using various characterization techniques, namely, x-ray diffraction, Raman, and x-ray photoelectron spectroscopy. Scanning electron microscopy and particle size analysis suggested that the diameter of MWCNTs increases with a rise in the growth temperature, but the nanotube density decreases at 750 °C. Temperature-dependent magnetization studies of the p-MWCNT and f-MWCNT samples were investigated using a quantum design physical property measurement system-vibrating sample magnetometer mode. The magnetic properties and the effect of the growth temperature and acid functionalization on the morphology of MWCNT were also investigated. The results revealed that the diamagnetism effect of the graphitic nanotubes is dominating for p-MWCNT, and it reduces for f-MWCNT. A possible explanation for this feature is discussed in detail in the later part of this article. It may be considered that this study, which emerged with different growth temperatures of MWCNTs using a facile method for gaining control over magnetic properties, can be fundamental for further consideration of magnetic MWCNTs for various potential applications.

Molten Salts CO2 Transformation: Lower Energy Input and High-Yield Carbon Nanotubes Production Induced by Zinc Oxide

Molten salt electrochemistry is cited as one of the most efficient ways to convert stable but unwanted CO2 into value-added chemical fuels and functional materials, in particular carbon nanotubes (CNTs). In this work, we report the high yield and scalable CO2-deriving CNTs by adding ZnO to molten carbonate electrolyte. The physicochemical properties such as crystal structure, morphology and element composition of the carbon products were characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), energy dispersive spectroscopy (EDS), X-ray diffractometer (XRD) and Raman spectrometer (Raman). It is demonstrated that an appropriate amount of ZnO additives can greatly increase the content of CNTs in carbon products. However, the micromorphology and microstructure of the carbon products are found to be significantly changed when the ZnO content is insufficient or excessive. Compared with molten salt electrolyte without ZnO, ZnO-included electrolyte endows CNTs with a higher degree of graphitization and crystallinity. This work demonstrates the feasibility of improving CNTs content in carbon products and lowering required energy for CNTs production by adding ZnO as a promoter.

Comparative life cycle assessment of high-yield synthesis routes for carbon dots

Carbon dots (CDs) are carbon-based nanomaterials with advantageous luminescent properties, making them promising alternatives to other molecular and nanosized fluorophores. However, the development of CDs is impaired by the low synthesis yield of standard fabrication strategies, making high-yield strategies essential. To help future studies to focus on cleaner production strategies, we have employed a Life Cycle Assessment (LCA) to compare and understand the environmental impacts of available routes for the high-yield synthesis of carbon dots. These routes were: (1) production of hydrochar, via hydrothermal treatment of carbon precursors, and its alkaline-peroxide treatment into high-yield carbon dots; (2) thermal treatment of carbon precursors mixed in a eutectic mixture of salts. Results show that the first synthesis route is associated with the lowest environmental impacts. This is attributed to the absence of the mixture of salts in the first synthesis route, which offsets its higher electricity consumption. Sensitivity analysis showed that the most critical parameter in the different synthetic strategies is the identity of the carbon precursor, with electricity being also relevant for the first synthesis route. Nevertheless, the use of some carbon precursors (as citric acid) with higher associated environmental impacts may be justified by their beneficial role in increasing the luminescent performance of carbon dots. Thus, the first synthesis route is indicated to be the most environmental benign and should be used as a basis in future studies aimed to the cleaner and high-yield production of carbon dots.

Yellow emission N-doped fluorescent carbon dots as fluorescent nanoprobes for the detection of L-threonine in real samples

High quantum yield carbon dots and their applications in the detection of L-threonine.

Target-oriented synthesis of high synthetic yield carbon dots with tailored surface functional groups for bioimaging of zebrafish, flocculation of heavy metal ions and ethanol detection

Target-oriented synthesis of multifunctional carbon dots with high synthetic yield is still a challenge. Herein, the acrylamide (AM) and acrylic acid (AA) which containing unsaturated carbon–carbon double bonds (CC) and different functional groups were chosen as switches for the directional synthesis of carrot derived carbon dots with water-solubility (WCDs) and ethanol-solubility (ECDs). The synthetic yield of WCDs and ECDs could reach up to 31.19% and 51.94% by the directional hydrothermal carbonization reaction adjusted by the free radical polymerization. Specifically, the WCDs inherited negative charge, amino group and high N element from the AM, while AA endowed the ECDs with electronic neutrality, ester group and low N content. Furthermore, the WCDs as probes for assessment of uptake and metabolism of zebrafish, integrated of flocculation and detection of the WCDs on heavy metal ions, and the ethanol detection performance of the ECDs in medical alcohol disinfectant were detailly investigated. Therefore, the high synthetic yield CDs prepared by target-oriented synthesis have application potential in bioimaging, flocculation and detection of heavy metal ions, and ethanol detection.

Carbon footprint of a typical pomelo production region in China based on farm survey data

Greenhouse gas emissions are a central environmental concern in China, and quantifying the carbon footprint of crop production can help identify key options for mitigating greenhouse gas emissions from agriculture. Using two-year farm survey data from a typical pomelo production area in China, the carbon footprint of a pomelo orchard was assessed by quantifying the greenhouse gas emissions from farming inputs and operations with a full life cycle assessment methodology. The carbon emission and carbon sequestration levels were 19.9 and 3.43 t CO2 eq ha−1, respectively. The farm carbon footprint and product carbon footprint were 16.5 t CO2 eq ha−1 and 0.33 t CO2 eq t−1, respectively, which were 3.8 and 1.5 times greater than the corresponding mean values for other fruit orchards in different areas of the world. Compared with farms with low yield and high carbon footprint, farms with high yield and low carbon footprint reduced nitrogen fertilizer input significantly, by 44.7%. Furthermore, the yield of farms which with high yield and low carbon footprint increased significantly by 69.4%, and the farm carbon footprint and product carbon footprint significantly decreased by 40.7% and 67.2%, respectively, compared to those of farms with low yield and high carbon footprint. The synthetic nitrogen fertilizer application rate was significantly linearly correlated with, and contributed 84.7% to the carbon footprint of pomelo production. The relationships between the carbon footprint and the nitrogen partial factor productivity also indicated that improving nitrogen utilization can effectively reduce greenhouse gas emissions. In addition, based on group analysis, the difference in carbon footprint among farm groups was also mainly due to nitrogen fertilization. Reducing costs can significantly improve carbon efficiency without affecting the economic benefit at similar yield levels. Therefore, the carbon intensity of pomelo production in China could be reduced primarily by reducing excessive nitrogen fertilizer application and potentially increasing nitrogen use efficiency. Apart from this, these differences could be implemented by modifying farming fertilization strategies and farm size. Overall, this study highlights the importance of strengthening nitrogen management in pomelo production based on agricultural practices as well as upscaling farm size, which could achieve higher yields with lower greenhouse gas emissions and thereby avoid tradeoffs between productivity and carbon costs.

Co-Catalyst-Free Chemical Fixation of CO2 into Cyclic Carbonates by using Metal-Organic Frameworks as Efficient Heterogeneous Catalysts.

The concentration of carbon dioxide (CO2 ) in the atmosphere is increasing at an alarming rate resulting in undesirable environmental issues. To mitigate this growing concentration of CO2 , selective carbon capture and storage/sequestration (CCS) are being investigated intensively. However, CCS technology is considered as an expensive and energy-intensive process. In this context, selective carbon capture and utilization (CCU) as a C1 feedstock to synthesize value-added chemicals and fuels is a promising step towards lowering the concentration of the atmospheric CO2 and for the production of high-value chemicals. Towards this direction, several strategies have been developed to convert CO2 , a Greenhouse gas (GHG) into useful chemicals by forming C-N, C-O, C-C, and C-H bonds. Among the various CO2 functionalization processes known, the cycloaddition of CO2 to epoxides has gained considerable interest owing to its 100% atom-economic nature producing cyclic carbonates or polycarbonates in high yield and selectivity. Among the various classes of catalysts studied for cycloaddition of CO2 to cyclic carbonates, porous metal-organic frameworks (MOFs) have gained a special interest due to their modular nature facilitating the introduction of a high density of Lewis acidic (LA) and CO2 -philic Lewis basic (LB) functionalities. However, most of the MOF-based catalysts reported for cycloaddition of CO2 to respective cyclic carbonates in high yields require additional co-catalyst, say tetra-n-butylammonium bromide (TBAB). On the contrary, the co-catalyst-free conversion of CO2 using rationally designed MOFs composed of both LA and LB sites is relatively less studied. In this review, we provide a comprehensive account of the research progress in the design of MOF based catalysts for environment-friendly, co-catalyst-free fixation of CO2 into cyclic carbonates.

Preparation of high-yield multi-walled carbon nanotubes by catalytic decomposition of mixture of natural gas and propylene and their electrothermal properties

Multi-walled carbon nanotubes (MWNTs) with high-yield were prepared by pyrolysis of mixture of natural gas (NG) and propylene (C3H6) over Fe-Ni/Al2O3-MgO catalyst. For C3H6/NG flow rate ratio ranging from 0 to 0.33, the carbon yield was increased from 903% to 4400%. The synthesized MWNTs after purification were dispersed by ball milling method and mixed with waterborne polyurethane to fabricate the electrothermal film. The mass fraction of CNT filler in the cured electrothermal film was controlled at 50%. The coating after drying was ca. 6 μm and the coating’s volume resistivity was 0.053 Ω·cm. The time-dependent temperature curves indicated that the heating rate of the electrothermal film was very fast under different low voltage and the steady-state temperatures were achieved within 100 s. The steady-state temperature reached 47.9 °C, 76.8 °C, and 102.8 °C, respectively at 10 V, 15 V, and 18 V.

Influences of tropical monsoon climatology on the delivery and dispersal of organic carbon over the Upper Gulf of Thailand

Organic carbon cycling in SE Asia is data-sparse and poorly studied, although high sediment yield and organic carbon intensity occur in the tropical region. In the present study, we evaluated the role of tropical monsoon pertaining to fluvial discharge, sediment load, coastal current and water stratification on seasonal organic carbon dynamics during four sampling campaigns in the Upper Gulf of Thailand (UGoT). This study demonstrates that particulate organic carbon (POC) is closely correlated with the river influx of suspended sediment, which is generally regulated by the local rainfall. Higher POC is found near the large estuarine section (Chao Phraya River, CHAO) during southwest monsoon period and the small estuarine section (Mae Klong River, MK) during November 2013 when tropical cyclones impacted. POC in the estuarine sections is more significantly influenced by the seasonal shift compared with the coastal sections. Land-derived organic matter prevails in the small estuarine and coastal sections, while marine-derived organic matter dominates in the estuarine sections impacted by CHAO and MK. Anthropogenic inputs and dam regulation also influences the river export of organic matter during the high precipitation periods. Total organic carbon (TOC) however displays less significant seasonal monsoon variations than POC. Further, TOC tends to accumulate in the sub-silt fraction of sediments, which mainly occurs in the small estuarine and eastern coastal sections and is more obviously influenced by marine-derived factors. TOC in sediment of the CHAO and MK influenced sections however displays more seasonal variations with prevailing river input evidenced by coarser sediment and higher C/N ratios. Moreover, the almost year round water stratification across the region acts as the barrier in retaining organic carbon in the estuaries and their vicinities from dispersal into the lower portion of Gulf of Thailand. High sedimentation rate (~1.1 cm·yr−1) further facilitates the organic carbon burial in the study area. The delivery, dispersal and burial of organic carbon are closely associated with the climate-controlled precipitation, and thus the tropical monsoon climatology under the global warming in particular is an important factor influencing the organic carbon in the UGoT.