Pour voir les autres types de publications sur ce sujet consultez le lien suivant : Fer-Carbon.
Articles de revues sur le sujet « Fer-Carbon »
Créez une référence correcte selon les styles APA, MLA, Chicago, Harvard et plusieurs autres
Consultez les 50 meilleurs articles de revues pour votre recherche sur le sujet « Fer-Carbon ».
À côté de chaque source dans la liste de références il y a un bouton « Ajouter à la bibliographie ». Cliquez sur ce bouton, et nous générerons automatiquement la référence bibliographique pour la source choisie selon votre style de citation préféré : APA, MLA, Harvard, Vancouver, Chicago, etc.
Vous pouvez aussi télécharger le texte intégral de la publication scolaire au format pdf et consulter son résumé en ligne lorsque ces informations sont inclues dans les métadonnées.
Parcourez les articles de revues sur diverses disciplines et organisez correctement votre bibliographie.
1
Fisher, Ben J., Johan C. Faust, Oliver W. Moore, Caroline L. Peacock et Christian März. « Technical note : Uncovering the influence of methodological variations on the extractability of iron-bound organic carbon ». Biogeosciences 18, no 11 (7 juin 2021) : 3409–19. http://dx.doi.org/10.5194/bg-18-3409-2021.
Texte intégralRésumé :
Abstract. Association of organic carbon (OC) with reactive iron (FeR) represents an important mechanism by which OC is protected against remineralisation in soils and marine sediments. Recent studies indicate that the molecular structure of organic compounds and/or the identity of associated FeR phases exert a control on the ability of an OC–FeR complex to be extracted by the citrate–bicarbonate–dithionite (CBD) method. However, many variations of the CBD extraction are used, and these are often uncalibrated to each other, rendering comparisons of OC–FeR values extracted via the different methods impossible. Here, we created synthetic ferrihydrite samples coprecipitated with simple organic structures and subjected these to modifications of the most common CBD method. We altered some of the method parameters (reagent concentration, time of the extraction and sample preparation methods) and measured FeR recovery to determine which (if any) modifications affected the release of FeR from the synthetic sample. We provide an assessment of the reducing capacity of Na dithionite in the CBD method (the amount of Fe reduced by a fixed amount of dithionite) and find that the concentration of dithionite deployed can limit OC–FeR extractability for sediments with a high FeR content. Additionally, we show that extending the length of any CBD extraction offers no benefit in removing FeR. Moreover, we demonstrate that for synthetic OC–FeR samples dominated by ferrihydrite, freeze-drying samples can significantly reduce OC–FeR extractability; this appears to be less of an issue for natural marine sediments where natural ageing mechanisms may mimic the freeze-drying process for more stable Fe phases. While our study is not an all-inclusive method comparison and is not aimed at delivering the “perfect” extraction setup, our findings provide a collected summary of critical factors which influence the efficiency of the CBD extraction for OC–FeR. As such, we provide a platform from which OC–FeR values obtained under different methods can be interpreted and future studies of sediment carbon cycling can build upon.
2
Hodgskiss, Malcolm S. W., Kelsey G. Lamothe, Galen P. Halverson et Erik A. Sperling. « Extending the record of the Lomagundi–Jatuli carbon isotope excursion in the Labrador Trough, Canada ». Canadian Journal of Earth Sciences 57, no 9 (septembre 2020) : 1089–102. http://dx.doi.org/10.1139/cjes-2019-0198.
Texte intégralRésumé :
The Labrador Trough in northern Québec and Labrador is a 900 km long Rhyacian–Orosirian orogenic belt containing mixed sedimentary–volcanic successions. Despite having been studied intensively since the 1940s, relatively few chemostratigraphic studies have been conducted. To improve our understanding of the Labrador Trough in the context of Earth history, and better constrain the local record of the Lomagundi–Jatuli carbon isotope excursion, high-resolution sampling and carbon isotope analyses of the Le Fer and Denault formations were conducted. Carbonate carbon isotopes (δ13C) in the Le Fer Formation record a large range in values from −4.4‰ to +6.9‰. This large range is likely attributable to a combination of post-depositional alteration and variable abundance of authigenic carbonate minerals; elemental ratios suggest that the most 13C-enriched samples reflect the composition of the water column at the time of deposition. Cumulatively, these data suggest that the Lomagundi–Jatuli Excursion was ongoing during deposition of the Le Fer Formation, approximately 2 km higher in the stratigraphy than previously recognised. However, the possibility of a post-Lomagundi–Jatuli Excursion carbon isotope event cannot conclusively be ruled out. The directly overlying Denault Formation records a range in δ13C values, from −0.5‰ to +4.3‰, suggesting that it was deposited after the conclusion of the Lomagundi–Jatuli Excursion and that the contact between the Le Fer and Denault formations occurred sometime during the transition out of the Lomagundi–Jatuli Excursion, ca. 2106 to 2057 Ma.
3
Berber, Mohamed R., Muhammad Imran, Hanako Nishino et Hiroyuki Uchida. « Impact of Pt-Loading and Carbon Support of Pt/C Anode Catalysts on Membrane Degradation Rate in Fuel Cells ». Journal of The Electrochemical Society 171, no 2 (1 février 2024) : 024502. http://dx.doi.org/10.1149/1945-7111/ad2733.
Texte intégralRésumé :
In order to clarify the effect of both the Pt-loading and carbon supports in various commercial Pt/C anode catalysts on the chemical degradation rate of polymer electrolyte membranes (PEMs) in fuel cells, the membrane lifetime and fluoride emission rate (FER) were examined in a single cell with an accelerated stress test (AST) at 90 °C, while the H2O2 production rates, j(H2O2), at the Pt/C catalysts were measured in a half cell with 0.1 M HClO4 solution at 90 °C. It was demonstrated that the PEM degradation rate decreased with decreasing amount of adsorbed hydrogen atoms (Had) at the Pt/C−PEM interface by lowering the Pt-loading and using a porous carbon support (locating Pt nanoparticles within pores). The use of a graphitized carbon black (GCB) support was found to be very effective to increase the lifetime due to it having the lowest j(H2O2), although this was accompanied by the disadvantage of decreased mass activity for the hydrogen oxidation reaction. We also found good correlations between the j(H2O2) measured in a half cell and FER, as well as lifetime in a single cell, so that the lifetime of the PEM can be estimated in a shorter time.
4
Kim, SH, SU An, WC Lee, JS Lee et JH Hyun. « Influence of Manila clam aquaculture on rates and partitioning of organic carbon oxidation in sediment of Keunso Bay, Yellow Sea ». Aquaculture Environment Interactions 12 (26 mars 2020) : 91–103. http://dx.doi.org/10.3354/aei00352.
Texte intégralRésumé :
We investigated the effects of Manila clam aquaculture on the rates and pathways of anaerobic organic carbon (OC) oxidation in highly bioturbated (HB) and poorly bioturbated (PB) sediment in Keunso Bay, Yellow Sea. Due to the labile organic matter supply via sediment reworking by Manila clams, the anaerobic OC oxidation rate in HB sediment (38.8 mmol m-2 d-1) was ~1.5 times higher than that in PB sediment (26.8 mmol m-2 d-1). Microbial Fe(III) reduction (FeR) dominated OC oxidation pathways in HB sediment, comprising 55 to 76% of anaerobic OC oxidation, whereas sulfate reduction (SR) was the dominant oxidation pathway in PB sediment, accounting for up to 92% of anaerobic OC oxidation. Despite higher anaerobic respiration rates at the HB site, concentrations of NH4+, PO43-, oxalate-extractable iron (Fe(II)(oxal)), and total reduced inorganic sulfur were 2 to 3 times lower in HB than in PB sediment. Conversely, the concentration of reactive Fe(III)(oxal) at the HB site (2243 mmol m-2) exceeded that at the PB site (1127 mmol m-2) by a factor of 2. These results indicate that bioturbation by Manila clams enhances the re-oxidation processes of reduced metabolites in the sediment, thereby prohibiting SR and promoting FeR. Overall, the results suggest that aquaculture activities of Manila clams shift the dominant OC oxidation pathways in sediment from SR to FeR, which generates relatively oxidized and less sulfidic environments.
5
Miletto, Ivana, Enrico Catizzone, Giuseppe Bonura, Chiara Ivaldi, Massimo Migliori, Enrica Gianotti, Leonardo Marchese, Francesco Frusteri et Girolamo Giordano. « In Situ FT-IR Characterization of CuZnZr/Ferrierite Hybrid Catalysts for One-Pot CO2-to-DME Conversion ». Materials 11, no 11 (14 novembre 2018) : 2275. http://dx.doi.org/10.3390/ma11112275.
Texte intégralRésumé :
CO2 hydrogenation to dimethyl ether (DME) is a promising strategy to drive the current chemical industry towards a low-carbon scenario since DME can be used as an eco-friendly fuel as well as a platform molecule for chemical production. A Cu‒ZnO‒ZrO2/ferrierite (CZZ/FER) hybrid grain was recently proposed as a catalyst for CO2-to-DME one-pot conversion exhibiting high DME productivity thanks to the unique shape-selectivity offered by ferrierite zeolite. Nevertheless, such a catalyst deactivates but no direct evidence has been reported of activity loss over time. In this work, CZZ/FER catalysts with different acidity levels were characterized with the FTIR technique before and after reactions, aiming to give new insights about catalyst deactivation. Results show that activity loss can be related to both (i) copper particle sintering, which decreases CO2 activation towards methanol, and (ii) acidity loss due to H+/Cu2+ ion exchange.
6
Rubeš, Miroslav, Michal Trachta, Eva Koudelková, Roman Bulánek, Jiří Klimeš, Petr Nachtigall et Ota Bludský. « Temperature Dependence of Carbon Monoxide Adsorption on a High-Silica H-FER Zeolite ». Journal of Physical Chemistry C 122, no 45 (25 octobre 2018) : 26088–95. http://dx.doi.org/10.1021/acs.jpcc.8b08935.
Texte intégral
7
Links, S., K. van Zyl, A. Cassiem, B. C. Flett, A. Viljoen et L. J. Rose. « The association of maize characteristics with resistance to Fusarium verticillioides and fumonisin accumulation in commercial maize cultivars ». World Mycotoxin Journal 13, no 3 (1 juillet 2020) : 367–79. http://dx.doi.org/10.3920/wmj2019.2537.
Texte intégralRésumé :
Fusarium verticillioides is the primary fungus that causes Fusarium ear rot (FER) of maize. Infection results in reduced grain yield and quality due to moulding and the contamination of grain with toxic compounds namely fumonisins. Resistance to fungal infection and fumonisin accumulation in maize and maize grain is governed at different levels. In this study, the structural, physico-chemical and genetic basis of resistance to F. verticillioides was investigated in two, replicated field trials at Potchefstroom and Vaalharts in South Africa. Phenotypic data (silk length, husk coverage, pericarp thickness hundred-kernel mass and kernel hardness), physico-chemical data (kernel pH, moisture content, total nitrogen and carbon as well as phenolic acid content) and the expression of pathogenesis-related-5 gene (PR5) and peroxidase gene expression was evaluated in 15 commercial cultivars under artificially inoculated and natural infection conditions. The data were correlated to FER severity, fumonisin accumulation and fungal DNA (referred to as infection indicators). Disease development and fumonisin contamination in Vaalharts was significantly more than in Potchefstroom. There were no significant correlations (r=≥0.60) between phenotypic characteristics and infection indicators. Kernel pH was the most important trait associated with disease development and was negatively correlated (between r=-0.58 and r=-0.75) to all infection indicators. PR5 gene expression had significant positive correlations (r=0.69 and r=0.72) with the fungal and fumonisin levels, respectively. This study presents of the first data demonstrating the use of gene expression in identifying FER/fumonisin-resistant plant material and could aid breeders and growers in selecting resistant material more effectively.
8
Dai, Chongshan, Hui Li, Yang Wang, Shusheng Tang, Tony Velkov et Jianzhong Shen. « Inhibition of Oxidative Stress and ALOX12 and NF-κB Pathways Contribute to the Protective Effect of Baicalein on Carbon Tetrachloride-Induced Acute Liver Injury ». Antioxidants 10, no 6 (18 juin 2021) : 976. http://dx.doi.org/10.3390/antiox10060976.
Texte intégralRésumé :
This study investigates the protective effect of baicalein on carbon tetrachloride (CCl4)-induced acute liver injury and the underlying molecular mechanisms. Mice were orally administrated baicalein at 25 and 100 mg/kg/day for 7 consecutive days or ferrostatin-1 (Fer-1) at 10 mg/kg was i.p. injected in mice at 2 and 24 h prior to CCl4 injection or the vehicle. Our results showed that baicalein or Fer-1 supplementation significantly attenuated CCl4 exposure-induced elevations of serum alanine aminotransferase and aspartate aminotransferase, and malondialdehyde levels in the liver tissues and unregulated glutathione levels. Baicalein treatment inhibited the nuclear factor kappa-B (NF-κB) pathway, activated the erythroid 2-related factor 2 (Nrf2)/heme oxygenase 1 (HO-1) pathway in liver tissues, and markedly improved CCl4-induced apoptosis, inflammation and ferroptosis in liver tissues exposed with CCl4. In vitro, baicalein treatment improved CCl4 -induced decreases of cell viabilities and knockdown of Nrf2 and arachidonate 12-lipoxygenase (ALOX12) genes partly abolished the protective effect of baicalein on CCl4 -induced cytotoxicity in HepG2 cells. In conclusion, our results reveal that baicalein supplementation ameliorates CCl4-induced acute liver injury in mice by upregulating the antioxidant defense pathways and downregulating oxidative stress, apoptosis, inflammation and ferroptosis, which involved the activation of Nrf2 pathway and the inhibition of ALOX12 and NF-κB pathways.
9
Castoldi, Lidia, Sara Morandi, Pierfrancesco Ticali, Roberto Matarrese et Luca Lietti. « An Assessment of Zeolite Framework Effect for Low-Temperature NOX Adsorbers ». Catalysts 13, no 6 (1 juin 2023) : 962. http://dx.doi.org/10.3390/catal13060962.
Texte intégralRésumé :
Pd-promoted zeolites (Y, ZSM-5, FER, SSZ-13) were prepared and characterized to analyze their properties as low-temperature NOx adsorbers. The samples were investigated by BET and XRD and by in situ FT-IR spectroscopy of CO and NO adsorption to probe the Pd sites and the nature of the adsorbed NOx species. The NOx adsorption/desorption performances at low temperatures were examined by microreactor measurements upon NO/O2 adsorption followed by TPD in the presence of water and carbon dioxide. It was enlightened that: (i) the zeolite framework influences the Pd dispersion: the smaller the zeolite cage, the higher the Pd dispersion, irrespective of the Si/Al ratio. Accordingly, the following Pd dispersion order has been observed, inversely to the zeolite cage size: Pd/SSZ-13 > Pd/ZSM-5 ~ Pd/FER >> Pd/Y; (ii) Pd is present as isolated Pdn+ species and in PdOx particles; (iii) the Pd dispersion governs the NOx storage capacity: the smaller the zeolite cage, the higher the Pd dispersion and the storage capacity; (iv) NO adsorbs mainly in the form of Pd nitrosyls and nitrates; (v) NO desorption occurs both at a temperature below 200 °C and in a high-temperature range (near 350 °C).
10
Olotu, Yahaya, Livinus Apebuamhe Izah, Moses Eromosele Eseigbe, Reuben Ishiekwene et John Friday Ogbodo. « Re-calibration of an automatic evaporimeter ». Studia Universitatis Babeș-Bolyai Engineering 67, no 1 (11 novembre 2022) : 162–71. http://dx.doi.org/10.24193/subbeng.2022.1.15.
Texte intégralRésumé :
A set of pre-programmed sensors and transducers, including 0.71 EAP, carbon resistor, semi-carbon conductor, IN4007, and lighting diode-4v, 60 mm amp, were used to develop and build an automatic evaporimeter for automating/self-recording evaporation rate. 10 ILP values, 8 FLP values, 150.4 and 12.3 refractive values, respectively, were used to design the evaporimeter's operating principle. The results of equipment calibration utilizing various statistical validations of voltage, calibration index, and refractive index values demonstrate high agreement with R2 values of 0.999, 0.869, and 16.4 correspondingly. Every level (0.1 cm) of the instrument's time response to a step change in the water level caused by evaporation in the pan was calibrated. The voltage (v) was 225.6v, the highest evaporation value was 0.3 cm, and the refractive index was 15.0. With R2 = 0.9718 and 0.9635, statistical validation shows that there was a significant correlation between the initial evaporation reading (IER) and the final evaporation reading (FER).
11
Pulido, A., M. R. Delgado, O. Bludský, M. Rubeš, P. Nachtigall et C. O. Areán. « Combined DFT/CC and IR spectroscopic studies on carbon dioxide adsorption on the zeolite H-FER ». Energy & ; Environmental Science 2, no 11 (2009) : 1187. http://dx.doi.org/10.1039/b911253g.
Texte intégral
12
Bulánek, Roman, Karel Frolich, Eva Frýdová et Pavel Čičmanec. « Microcalorimetric and FTIR Study of the Adsorption of Carbon Dioxide on Alkali-Metal Exchanged FER Zeolites ». Topics in Catalysis 53, no 19-20 (5 octobre 2010) : 1349–60. http://dx.doi.org/10.1007/s11244-010-9593-6.
Texte intégral
13
Lv, Jiangang, Long Chen, Chong Chen, Yunzheng Wang, Di Wang, Huaqian Sun et Weimin Yang. « Activity Enhancement of Ferrierite in Dimethyl Ether Carbonylation Reactions through Recrystallization with Sodium Oleate ». Molecules 28, no 13 (7 juillet 2023) : 5279. http://dx.doi.org/10.3390/molecules28135279.
Texte intégralRésumé :
Methyl acetate (MA) has a wide range of applications as an important industrial chemical. Traditional MOR zeolite for carbonylation of DME to MA accumulated carbon easily because of a 12-membered ring (12 MR) channel. In this work, we innovatively developed the method of recrystallization ferrierite (FER) zeolite using special chelating ligand sodium oleate which can affect ions other than alkali metals. The characterization results of N2 adsorption, transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy (FT-IR) show that hydrothermal recrystallization of ferrierite using sodium oleate resulted in a higher Si/Al ratio, a bigger specific surface area and a larger number of Brønsted acid sites in the eight MR channels, which was more efficient in the reaction of carbonylation of dimethyl ether than ordinary alkali treatment.
14
Nakamura, Shogo, Kojiro Sanami, Zulfi Gautama, Zhiyun Noda, Masahiro Yasutake, Stephen M. Lyth, Masamichi Nishihara et Kazunari Sasaki. « Effect of Contamination in the Carbon Catalyst Support on Chemical Degradation of Polymer Electrolyte Membranes in Fuel Cells ». ECS Meeting Abstracts MA2024-02, no 43 (22 novembre 2024) : 2951. https://doi.org/10.1149/ma2024-02432951mtgabs.
Texte intégralRésumé :
Introduction One of the key components of polymer electrolyte fuel cells (PEFCs) is the polymer electrolyte membrane (PEM). The PEM facilitates the transport of protons from the anode to the cathode, acts as an electronic insulator to prevent short circuits, and plays a role in preventing the direct reaction of hydrogen gas and oxygen in air. One of the major technical issues with PEMs is their chemical degradation, causing decomposition of their molecular structure. This leads to reduced protonic conductivity, increased hydrogen and oxygen crossover, and reduced mechanical strength, all of which significantly affect the power generation performance and durability of PEFCs (1). In addition, in our laboratory, the use of SnO2 and mesoporous carbon (MC) as cathode catalyst supports has been suggested to suppress membrane degradation (2). However, the relationship between the cathode catalyst materials and the chemical degradation of PEM has not yet been fully understood. Here in this study, we conduct durability tests such as accelerated chemical degradation of PEM in cells using cathode electrocatalysts with different carbon support materials, aiming to clarify the effects of carbon support materials properties (structure, contaminants, and graphitization) on the chemical degradation of electrolyte membranes. Experimental A commercial Pt/KB catalyst (TEC10E50E, Tanaka Kikinzoku Kogyo, Japan) was used as the anode catalyst. Several types of cathode catalysts were applied and compared: the commercial Pt/KB; Pt/MC where Pt was directly deposited on the MC; and various electrocatalysts where Pt was directly deposited on carbon supports such as graphitized AB (acetylene black). The durability test at open circuit voltage (OCV) was performed for 100 h. Before and after the durability test, cell performance, hydrogen crossover current density, and electrochemical surface area (ECSA) were characterized. The degree of membrane degradation was evaluated by measuring fluoride-ion emission rate (FER) by ion chromatography, and membrane thickness by cross-sectional observation with a focused-ion-beam scanning electron microscope (FIB-SEM), as illustrated in Fig.1. Moreover, contaminants and graphitization of the carbon support materials were also analyzed, and their relationship to membrane degradation was considered. Results and discussion The results of OCV holding tests up to 100 h for four different MEAs are shown in Fig. 2. The voltage drop in using Pt/MC as cathode catalysts was smaller than that in using Pt/KB. The FER of Pt/MC as cathode catalysts was lower than that of Pt/KB as shown in Fig. 3, suggesting that the use of MC as carbon supports may suppress PEM degradation. In this presentation, we will show the effects of carbon support materials properties (structure, contaminants, and graphitization) in cathode catalysts on PEM degradation, and discuss possible mechanisms based on the characteristics of various carbon supports. Acknowledgements This paper is based on results obtained from a project, JPNP20003, commissioned by the New Energy and Industrial Technology Development Organization (NEDO). An educational part for young scientists was supported by the Japan Science and Technology Agency (JST) through the program “Adopting Sustainable Partnerships for Innovative Research Ecosystem” (ASPIRE), Grant Number JPMJAP2307. The presenting author (S. Nakamura) is supported by the Miyamoto Jun-ichi Hydrogen Research Award, and the Kyushu University Q-PIT Support Program for Young Researchers and Doctoral Students. References M. Zatoń, J. Rozière, and D. J. Jones, Sustain. Energy Fuels, 1, 409 (2017). S. Nakamura, T. Ogawa, Z. Gautama, Z. Noda, M. Yasutake, S. M. Lyth, J. Matsuda, A. Hayashi, M. Nishihara, and K. Sasaki, ECS Trans., 112 (4), 315 (2023). Figure 1
15
Nachtigall, P., O. Bludský, L. Grajciar, D. Nachtigallová, M. R. Delgado et C. O. Areán. « Computational and FTIR spectroscopic studies on carbon monoxide and dinitrogen adsorption on a high-silica H-FER zeolite ». Phys. Chem. Chem. Phys. 11, no 5 (2009) : 791–802. http://dx.doi.org/10.1039/b812873a.
Texte intégral
16
Feng, Pei, Guanqun Zhang, Kailu Zang, Xiujie Li, Longya Xu et Xiaofang Chen. « A theoretical study on the selective adsorption behavior of dimethyl ether and carbon monoxide on H-FER zeolites ». Chemical Physics Letters 684 (septembre 2017) : 279–84. http://dx.doi.org/10.1016/j.cplett.2017.07.005.
Texte intégral
17
Magbolah Salem Helal Alzahrani. « Therapeutic Functions of Artemisia Judaica in Rats Injected with Carbon Tetrachloride (Ccl4) ». Journal of Electrical Systems 20, no 1 (25 janvier 2024) : 464–72. http://dx.doi.org/10.52783/jes.5382.
Texte intégralRésumé :
There are many types of liver disease, which can be caused by infections, inherited conditions, obesity and misuse of alcohol. Over time, liver disease may lead to scarring and more serious complications , so we worked on this investigation to magnify the therapeutic applications of Artemisia judaica in carbon tetrachloride-injected rats (Ccl4). The experiment was carried out in a caged animal. All rats were fed a basal diet for one week before the study, and they were divided into five groups, each with six rats. As control negative normal rats (C–ve), the first group sample was fed only the basal diet for 28 days. The remaining rats (n=24) were injected with carbon tetrachloride (Ccl4). Four groups were fed varying concentrations of (5%, 10%, 15% Artemisia judaica, whereas one group was diagnosed with the illness and disease, and didn't even feed the experimental diet. The results showed that highest value of feed efficiency ratio (FER) was found in 15% Artemisia judaica. It is noticed that a significant decreases in BWG% for the control group compared to all groups. Also, The strongest effect in serum AST levels was recorded for group 5 which fed on 15% Artemisia Judaica, while the rats fed on different levels of Artemisia judaica were lower than the positive control group and higher than the negative control groups. The study recommended feeding Artemisia judaica in different concentrations, especially 15%.
18
Ageeva, M. V., et V. A. Demin. « Conjugate mass transfer and immobilization of silicon vapor during the saturation of a porous medium based on carbon fiber ». ВЕСТНИК ПЕРМСКОГО УНИВЕРСИТЕТА. ФИЗИКА, no 4 (2023) : 5–9. http://dx.doi.org/10.17072/1994-3598-2023-4-05-09.
Texte intégralRésumé :
We constructed a conjugate physical and mathematical model that describes a high-temperature mass transfer of silicon vapor from the melt mirror to a porous carbon material, the process of its filtration, and deposition inside the sample. In the outer region, the distribution of vapor is deter-mined by a general nonlinear diffusion equation that takes into account the convective mass trans-fer in the working space of the retort. Inside the porous sample, the behavior of gaseous silicon is described by a system of equations in the framework of the MIM-approach. It is assumed that the silicon deposition mainly depends on the temperature distribution inside the sample. For simplicity, a one-dimensional problem is considered. The boundary conditions are chosen taking into account the significantly different permeabilities of the carrier medium and the porous carbon fiber. The temperature outside the material is assumed to be constant, while inside a non-uniform distribution is maintained. The constructed boundary value problem was solved numerically with the use of the finite difference method. The distributions of silicon vapor outside and inside the sample were ob-tained. It is shown that the non-linearity in the mass transfer equation leads to a distortion of the distribution from the melt mirror to the sample, which indicates a significant contribution of the convective mass transfer to the silicon vapor flow in this region.
19
Berber, Mohamed, Muhammad Imran, Hanako Nishino et Hiroyuki Uchida. « Impact of Metal Oxide Nanoparticles in Anode Catalyst Layer on Membrane Degradation and Output Performance of PEFC ». ECS Meeting Abstracts MA2024-02, no 41 (22 novembre 2024) : 2731. https://doi.org/10.1149/ma2024-02412731mtgabs.
Texte intégralRésumé :
The chemical degradation of polymer electrolyte membranes (PEMs) is one of the most serious issues that need to be addressed to achieve a long lifetime for the polymer electrolyte fuel cells (PEFCs). The PEMs such as Nafion (perfulorinated sulfonic acid polymers) are attacked by ·OH radicals generated from the decomposition of H2O2molecules, which are predominantly produced at the Pt/C anode catalyst layer (ACL).1 The addition of metal oxide nanoparticles (NPs) such as CeO2 and MnO2 to PEM or anode side has been introduced as one of the effective solutions to demolish the chemical degradation of PEM by scavenging the ·OH radical through the redox properties of these metal ions.1‒3 Although the lifetime of the PEMs have effectively prolonged, the proton conductivity of both the PEM and the ionomer binder in the cathode catalyst layer (CCL) has dramatically decreased, resulting in an appreciable loss of the output performance,4, 5 i.e., trade-off relationship between the durability and the output performance. To suppress the membrane degradation accompanied with increased output performance, we have proposed a unique concept of addition of metal oxide NPs without releasing the metal ions into ACL. The silica NPs were the first that exhibited such excellent properties.6 In the present research, we offer a new candidate of metal(IV) oxide (MO2) NPs which played a great role in increasing the lifetime of Nafion-PEM much longer than in the case of using silica NPs. The catalyst-coated membranes (CCMs) of the current study have been prepared as reported in our previous work.6 The fabricated CCMs comprised Nafion 211 (NRE-211; 25 µm in thickness) as the PEM, heat-treated Pt/graphitized carbon black (Pt/GCB-HT, TEC10EA50E-HT, 50.2 wt%-Pt) as the cathode catalyst, and Pt supported on carbon black (Pt/C, TEC10E50E, 46.4 wt%-Pt) as the anode catalyst, in which MO2-NPs were incorporated with a changeable volume ratio to the carbon content (VMO 2/VC, ranging from 0 to 0.4). Each CCM was mounted in a single cell (geometric electrode area 29.2 cm2). The chemical stability of the PEM was examined via an accelerated stress test (AST) in which the single cell was maintained at open circuit voltage (OCV) in a 40% humidified H2/air at Tcell = 90 °C and a backpressure of 160 kPa-G.6 As a measure of the durability of the PEM, the lifetime is defined as the time at which the OCV reached 0.85 V (ca. 10% loss). Figure 1 shows the changes of the OCV and the total amount of fluoride (F−) ions emitted during the AST. The OCV of the cell without any metal oxide in the ACL (denoted as Pt/C only in Fig. 1) has rapidly dropped, reaching values below 0.85 V with a very high F− emission rate (FER, slope of the line in Fig. 1b) after ca. 150 h of durability testing. With the addition of silica at VSiO2/VC = 0.2 in the ACL, the lifetime has appreciably increased (ca. 570 h) with a low FER. It is striking for the MO2-based ACL with VMO2/VC =0.2 that the lifetime has been remarkably prolonged, reaching ca. 1650 h (ca. 11 times increase of the Nafion lifetime) together with the lowest FER. Also, it has been found that the use of silica NPs has provided a reduced ohmic resistance (increase in water content of PEM and ionomers) and an effective utilization of Pt cathode catalyst in a single cell, which contributed to increase the output I-V performance.6 A similar effect was observed for the incorporation of MO2 NPs into the ACL. Such an improvement of the output performance accompanied with the remarkable increase in the durability of PEM is quite distinct from the trade-off effect of conventional radical scavengers. The mechanism for suppression of membrane degradation, as well as the changes in the microstructure of CCM, are under progress in our laboratory. This work was supported by funds for the “R&D of novel anode catalyst project” from the New Energy and Industrial Technology Development Organization (NEDO) of Japan. References Endoh, ECS Trans., 16(2), 1229 (2008). Zhao, B.L. Yi, H.M. Zhang, and H.M. Yu, J. Membr. Sci., 346, 143 (2010). Wang, C. Cai, J. Tan, and M. Pan, Int. J. Hydrogen Energy, 46, 34867 (2021). Lin, C. Cao, H. Zhang, H. Huang, and J. Ma, Int. J. Hydrogen Energy, 37, 4648 (2012). H. Wong and E. Kjeang, J. Electrochem. Soc., 166, F128 (2019). Mohamed R. Berber, M. Imran, H. Nishino, and H. Uchida, ACS Appl. Mater. Interfaces, 15, 13219 (2023). Figure 1
20
Iglesias, Hasler, Ana Paredes Ortiz, José M. Soriano Disla et Andrés J. Lara-Guillén. « Environmental and Economic Life Cycle Impacts of Using Spent Mushroom Substrate as a Soil Improver ». Environments 12, no 1 (20 janvier 2025) : 31. https://doi.org/10.3390/environments12010031.
Texte intégralRésumé :
The cultivation of white button mushrooms (Agaricus bisporus) generates significant quantities of spent mushroom substrate (SMS), a byproduct traditionally treated as waste despite its nutrient- and organic-carbon-rich composition. The EU-funded project FER-PLAY identified SMS as one of the most promising circular fertilizers (i.e., those produced from waste streams, transforming them into value-added products). Within the project, a life cycle assessment (LCA) and life cycle costing (LCC) analysis of SMS were conducted with a cradle-to-gate-to-grave scope across three European regions, comparing it to a non-renewable mix with equivalent N, P, K, and C inputs. The LCA results reveal substantial environmental benefits of SMS over the non-renewable baseline, particularly in land use, fossil resource depletion, freshwater ecotoxicity and climate change, which together account for 98% of total impacts. Although SMS exhibits higher water consumption, it represents only 2% of total impacts. LCC highlights the critical effects of fresh mushroom substrate composition on yield, economies of scale, and revenue generation. Overall, this study highlights the significant environmental and economic potential of repurposing SMS as a soil improver, offering a compelling case for its integration into agricultural systems as part of a sustainable, circular economy.
21
da Rocha Junior, Paulo Roberto, Felipe Vaz Andrade, Guilherme Kangussú Donagemma, Fabiano de Carvalho Balieiro, Eduardo de Sá Mendonça, Adriel Lima Nascimento, Fábio Ribeiro Pires et André Orlandi Nardotto Júnior. « CO2 Flux Emissions by Fixed and Mobile Soil Collars Under Different Pasture Management Practices ». AgriEngineering 6, no 4 (15 novembre 2024) : 4325–36. http://dx.doi.org/10.3390/agriengineering6040244.
Texte intégralRésumé :
Carbon dioxide flux emissions (CFE) from agricultural areas exhibit spatial and temporal variability, and the best time of collar fixation to the soil prior to the collection of CO2 flux, or even its existence as a factor, is unclear. The objective of this study was to evaluate the effect of the fixation time of collars that support the soil-gas flux chamber based on the influence of CFE on different pasture management practices: control (traditional pasture management practice) (CON), chisel (CHI), fertilized (FER), burned (BUR), integrated crop-livestock (iCL), and plowing and harrowing (PH). A field study was conducted on the clayey soil of Udults. The evaluations were performed monthly by fixing the PVC collars 30 d and 30 min prior to each CFE measurement. Although a linear trend in CFE was observed within each pasture management practice between the two collar-fixation times, collar fixation performed 30 min prior led to an overestimation of CFE by approximately 32.7% compared with 30 d of collar fixation. Thus, CFE were higher (p ≤ 0.10) in the MC, when compared to the FC, when the CON, BUR, and iCL managements were evaluated. Overall, fixing the collar 30 d prior to field data collection can improve the quality of the data, making the results more representative of actual field conditions.
22
Mesa, Juan, Scott Blackburn, Austin Plymill, Gerald Brown, Andrew M. Park, Devproshad Paul et Shawn Litster. « Electrode Ionomer Accelerated Stress Test Applied to High Oxygen Permeability Ionomer in Fuel Cells ». ECS Meeting Abstracts MA2022-02, no 41 (9 octobre 2022) : 1504. http://dx.doi.org/10.1149/ma2022-02411504mtgabs.
Texte intégralRésumé :
Perfluorosulfonic acid (PFSA) polymer electrolytes are widely used in proton exchange membrane (PEM) fuel cell fabrication for the membrane separator and the electrode binder. The PEM serves to electrically insulate the cathode catalyst layer (CCL) from anode catalyst layer (ACL), provide proton conduction between both CCL and ACL, as well as prevent gas crossover. PFSA ionomers are also used in the CCL and ACL to mechanically bind the catalyst particles into thin-films, provide proton conduction between the PEM and catalyst surface, and produce a high proton reactant concentration at the oxygen reduction reaction catalyst. Despite their versatility to be used as a membrane and catalyst binder, the typical PFSA ionomers pose challenges due to the high oxygen transport resistance that is introduced by the thin ionomer films over the catalyst. In recent years, novel high oxygen permeability ionomers (HOPIs) have been developed as the successor to the traditional Nafion™ PFSA ionomers. Despite their remarkable results as a catalyst binder due to their increased oxygen transport rates, less is known regarding their degradation and functional lifetime. Although accelerated stress tests (ASTs) for platinum (Pt)/Pt-alloy catalysts, carbon supports, and membranes are well-established and commonly applied, there is no standard and easily implemented AST for electrode ionomers. One challenge is that membrane ASTs usually quantify the fluoride emission rate (FER) to assess chemical degradation, which is difficult to apply for electrode PFSA ionomer when also using a PFSA membrane because the FER is overwhelmed by membrane signal. In addition, changes in OCV and H2 crossover are not directly indicative of electrode ionomer degradation. Furthermore, concomitant degradation of the catalyst and support can interfere with interpreting electrode ionomer degradation. Here we present an effective and easily applied electrode ionomer chemical AST protocol that can be used to evaluate degradation in the functionality of the electrode ionomer. The approach borrows the chemical AST conditions of the chemical membrane AST’s open circuit voltage (OCV) hold and avoids excessive potential cycling to minimize catalyst and support degradation that will elicit changes in electrode properties separate from ionomer degradation. During the AST, we measure the cathode’s proton conduction resistance, oxygen permeability, and electrochemically surface area (ECSA) to evaluate the degradation of the ionomer’s functionality. Thus, this protocol can be used to assess if more complex and time consuming analyses of ionomer durability are needed as new chemistries emerge. Here we present results of this AST to both conventional PFSA ionomers and HOPIs.
23
Jendrlin, Martin, Julien Grand, Louwanda Lakiss, Philippe Bazin, Svetlana Mintova et Vladimir Zholobenko. « Environmental Applications of Zeolites : Preparation and Screening of Cu-Modified Zeolites as Potential CO Sensors ». Chemistry 5, no 1 (20 février 2023) : 314–33. http://dx.doi.org/10.3390/chemistry5010024.
Texte intégralRésumé :
This work is focused on the application of Cu-containing zeolites as potential environmental sensors for monitoring carbon monoxide. A number of commercial zeolites with different structural properties (NaX, NaY, MOR, FER, BEA and ZSM-5) were modified using CuSO4, Cu(NO3)2 and Cu(OAc)2 solutions as copper sources to prepare Cu+-containing zeolites, since Cu+ forms stable complexes with CO at room temperature that can be monitored by infrared spectroscopy. Zeolite impregnation with Cu(NO3)2 resulted in the highest total Cu-loadings, while the Cu(OAc)2-treated samples had the highest Cu+/Cutotal ratio. Cu(NO3)2-impregnated MOR, which displayed the highest concentration of Cu+, was subjected to a number of tests to evaluate its performance as a potential CO sensor. The working temperature and concentration ranges of the sensor were determined to be from 20 to 300 °C and from 10 to 10,000 ppm, respectively. The stepwise CO desorption experiments indicated that the sensor can be regenerated at 400 °C if required. Additional analyses under realistic flow conditions demonstrated that for hydrophilic zeolites, the co-adsorption of water can compromise the sensor’s performance. Therefore, a hydrophobic Sn-BEA was utilised as a parent material for the preparation of an impregnated Cu-Sn-BEA zeolite, which exhibited superior resistance to interfering water while maintaining its sensing properties. Overall, the prepared Cu-modified zeolites showed promising potential as environmental CO sensors, displaying high sensitivity and selectivity under representative testing conditions.
24
Zhang, Wei, Shaoai Xie, Hongjin Chen, Mei Li, Li Ma et Jinping Jia. « Anodic Electrochemical Pretreatment Time and Potential Affect the Electrochemical Characteristics of Moderately Boron-Doped Diamond Electrode ». Collection of Czechoslovak Chemical Communications 73, no 1 (2008) : 73–87. http://dx.doi.org/10.1135/cccc20080073.
Texte intégralRésumé :
Boron-doped diamond (BDD) electrodes, both as-prepared and electrochemically oxidized were studied. The relation between the anodic oxidation treatment time, anodic potential and electrochemical characteristics has been discussed. Electron transfer processes in all BDD electrode surface were studied by cyclic voltammetry. The ferric/ferrous sulfate and ferri/ ferrocyanide redox systems were chosen respectively to act as the probe of one-electron trans- fer processes. The relation between ∆Ep and ψ, the dimensionless parameter, was obtained with a correlation coefficient greater than 0.9987 by mathematics fitting function. The rate constants of the electron transfer reaction, k0, were evaluated using the ∆Ep values. The k0 values for all BDD electrodes ranged from 3.33 × 10-5 to 4.72 × 10-5 cm s-1 in 0.1 M FeSO4/ 0.1 M H2SO4 and from 1.01 × 10-4 to 2.49 × 10-4 cm s-1 in 0.1 M K4[Fe(CN)6]/0.1 M H2SO4 system, which were in the standard range for a quasi-reversible system, respectively. The electrochemical properties of the BDD electrodes changed as a function of the surface anodic treatment time and potential. The anodic oxidation at low potential stripped mainly the impurities of BDD surface, sp2-carbon, and had little effect on the modification of the surface. While increasing the anodic potential up to +2.0 V, the anodic oxidation stripped the impurities of the BDD surface at first and carried out the modification of the BDD surface from hydrogen-terminated hydrophobic to oxygen-terminated hydrophilic surface with increasing anodic treatment time.
25
Kaplin, Mykola, et Tetiana Bilan. « Aggregated energy supply model according to product energy balance data structure ». System Research in Energy 2023, no 2 (9 juin 2023) : 48–61. http://dx.doi.org/10.15407/srenergy2023.02.048.
Texte intégralRésumé :
An economic-mathematical model of the production type was developed, intended for forecasting the country's energy supply by calculating the balanced supply of carbon-containing fuels, electricity and heat from fossil fuel and renewable energy sources. The model was built on the basis of open data sources according to the specific structure of technological methods by L.V. Kantorovich, which, unlike the known ones, uses subsystems for the production of abstract products that correspond to the range of outputs and inputs of the product energy balance, and also uses procedures for their selective aggregation to build various forms of inter-product balance matrices. This allowed us to obtain a tool for forecasting and assessing energy balances that is resistant to the growing limitations of information support, which is distinguished by a new system of conditions for a production-type model for the expanded range of the International Energy Agency's product energy balance, as well as a set of technological methods proposed for the first time by L.V. Kantorovich, which together determined the structure of output, costs and product links of individual producers of the energy supply system within the framework of a mutually agreed multi-product balance. The proposed model provides opportunities for using statistical and technological approaches to determining output and cost coefficients in solving forecasting problems, applying inherent means of analyzing retrospective balances to identify unaccounted volumes of FER, as well as volumes of their consumption and transformation in the country's energy sector with significant changes in the structure of electricity and heat generation capacities. The forecasted volumes of supply of the main types of energy resources obtained in the calculations using the developed energy supply model allowed us to assert that, given the indicators of energy efficiency achieved in 2020, the country's energy supply system is able to meet the country's needs mainly through the development of domestic fuel bases. Keywords: energy supply, product energy balance, production type model.
26
LAL BAHADUR, D.D. TIWARI, J. MISHRA et B.R. GUPTA. « Evaluation of integrated nutrient management options in rice (Oryza sativa) wheat (Triticum aestivum) cropping system in reclaimed sodic land ». Indian Journal of Agronomy 58, no 2 (10 octobre 2001) : 137–45. http://dx.doi.org/10.59797/ija.v58i2.4180.
Texte intégralRésumé :
Nutrient management is one of the major problem of the sodic land due to low organic matter status and toxicity of sodium, which reduced the availability of other nutrients and affects the soil properties. A field experiment was conducted to evaluate the integrated nutrient management options in sodic soil at Shivali Village of C.S.A. Univer- sity of Agriculture and Technology, Kanpur during 2005-06 and 2006-07. The physico-chemical properties of the soil were pH - 8.9, EC - 0.61 dS/m, organic carbon - 3.6 g/kg, CaCO -1.24%, GR-7.92 t/ha, sand-56%, silt- (2.5) (2.5) 3 28%, clay-16% (sandy loam), available N-156 kg/ha, available P-25.3 kg/ha, available K-235 kg/ha and available Zn-0.78 ppm. Results indicated that plant height, fertile tillers, biomass/hill, length of ear, test weight, grain and straw yield of rice (Oryza sativa L.) and wheat {Triticum aestivum (L.) emend. Fiori & Paol} significantly increased by application of fertilizer on the soil test basis in comparison to farmers practice. Further increased the yield and yield attributing characters when organic manures (FYM, pressmud and NADEP compost) added @ 5 t/ha with the recommended doses of fertilizers. Application of organic manure (FYM) integrated with recommended dose of fer- tilizers and biofertilizers (PSB + BGA/ Azotobacter) further increased the yield and yield attributing characters of rice and wheat which was similar to 125% recommended dose of fertilizers. The maximum grain yield of rice and wheat (5.46 and 3.57 t/ha) was recorded with application of NPKZn based on soil test + FYM @ 5 t/ha + PSB + BGA. Similar trends were also recorded in case of nutrient uptake. In case of microbial populations, maximum bacterial population (94.0 105/g soil) and Azotobacter (51.5 102/g soil) was recorded with application of NPK Zn based on soil test + FYM @ 5 t/ha + PSB + BGA and maximum PSB count (42.0 102/g soil) was recorded in with application NPK Zn based on soil test+PSB+BGA. The Actinomycetes population was not affected by the different treatments. Improvement in soil properties (pH, EC, OC) and soil fertility status (NPK and Zn) was recorded when chemical fertilizers were integrated with organic manures.
27
Demydenko, O., V. Prybluda, Yu Zapasna et V. Velychko. « Agrogenesis of regraded chernozem and the performance of grain crops under organic system of fertilization ». Agricultural Science and Practice 4, no 3 (15 décembre 2017) : 50–61. http://dx.doi.org/10.15407/agrisp4.03.050.
Texte intégralRésumé :
Aim. To conduct complex agrophysical, physical-chemical substantiation of the effi ciency of the organic fer- tilization system in terms of nitrogen balance and organic carbon in the agroecosystem of a fi ve-fi eld grain- growing and weeding crop rotation fi lled with cereals and legumes up to 40 % and the use of by-products for fertility restoration and improvement of the agrogenesis of regraded chernozem in the central part of the Forest-Steppe of Ukraine. Methods. Laboratory-analytical, experimental fi eld, computational, statistical. Results. The systematic application of the organic system of fertilization in a short grain-growing and weeding crop rotation with the use of by-products as organic fertilizers promotes the increase in the points of exchange neutrality and the decrease in the unsaturation of regraded chernozem with the alkali of the tilled layer, while the increase in microaggregation and structure-building is conditioned by the approximation of potential acid- ity to the isoelectric state of soil colloids which is a feature of the process of biologization and simulation of natural soil formation in agroecosystems of the central part of the Forest-Steppe of Ukraine. Under the organic fertilization system the decrease in the agroecosystem performance is related to the decrease in the volume of nitrogen balance which testifi es to the decrease in the intensity of its circulation in agroecosystem: the processes of enhancing the humifi cation of by-products and the formation of prohumus substances prevail, ac- companied with the intensifi cation of atmospheric CO 2 involvement in the formation of the total phytomass of the harvest, and the agroecosystem transforms into a stock system, which may be characterized as a basic sys- tem for organic production of plant cultivation. Conclusions. The elaborated system of organic fertilization of crops in a fi ve-fi eld grain-growing and weeding crop rotation allows avoiding the use of organic fertilizers and perennial grasses and using by-products of plant cultivation instead to saturate the crop rotation with legumes up to 30–40 %, the application of nitrogen-fi xing and phosphate-mobilizing preparations allows ensuring the production of organically pure products with simultaneous restoration of both fertility and the natural model of the chernozem agrogenesis of the central part of the Forest-Steppe of Ukraine.
28
Szigel, Gábor. « Carbon Intensity of Banks’ Loan Portfolio : A Good Basis for Comparison in Case of LowIncome Countries ? » Financial and Economic Review 21, no 4 (2022) : 83–102. http://dx.doi.org/10.33893/fer.21.4.83.
Texte intégralRésumé :
In recent years, more and more credit institutions have been publishing the financed carbon footprint of their loan portfolio, enabling comparisons across institutions, for which investors and supervisors tend to use the carbon intensity of portfolios expressed as a proportion of the financed carbon footprint-to-total loan volumes. In this article, it is argued that such comparisons are unfair to low-income countries with low price levels, as they show the same activity as being more “carbonintensive” in a low-income country than in a high-income country. The magnitude of such distortions can be significant, amounting to as much as 3 to 7-fold just within the European Union itself. As differences resulting from price levels do not actually represent differences in the carbon intensity of individual countries’ real economy and are also not an “own choice” of these countries (but rather a consequence of the Balassa-Samuelson effect), it is argued that the comparison of carbon intensity of different banks’ loan portfolios should be conducted using purchasing power parity adjustments – if not necessarily for investors, at least in the practice of financial supervisory authorities.
29
Várgedő, Bálint. « Climate Stress Test : The Impact of Carbon Price Shock on the Probability of Default in the Hungarian Banking System ». Financial and Economic Review 21, no 4 (2022) : 57–82. http://dx.doi.org/10.33893/fer.21.4.57.
Texte intégralRésumé :
This study presents the methodology and results of a transition risk climate stress test carried out for credit institutions, focusing on the methodology of a sectoral module developed for the analysis. Using a sectoral network derived from an inputoutput table, the sectoral module distributes a price shock between activities with higher greenhouse gas emission intensity and the related sectors. Results suggest that the sectors with the largest exposure to transition are electricity and gas supply. The probability of default for these two sectors may increase by 1.5 to 2.3 percentage points compared to the baseline. The transition risks for various sectors are highly heterogeneous. Based on Monte Carlo simulations, the extent of the transition risks for Hungarian banks also varies significantly. The advantage of this methodology lies in its ability to estimate the magnitude of macroeconomic shocks and the transition differences across sectors, and its ease of integration into stress testing processes.
30
Nakamura, Shogo, Taichi Ogawa, Zulfi Gautama, Zhiyun Noda, Masahiro Yasutake, Stephen Matthew Lyth, Junko Matsuda, Akari Hayashi, Masamichi Nishihara et Kazunari Sasaki. « Suppression of PEFC Membrane Degradation By Using SnO2 As Electrocatalyst Support ». ECS Meeting Abstracts MA2023-02, no 39 (22 décembre 2023) : 1924. http://dx.doi.org/10.1149/ma2023-02391924mtgabs.
Texte intégralRésumé :
Introduction Long-term durability of polymer electrolyte fuel cells (PEFCs) is required for various applications such as automobiles. It has been suggested that certain ions dissolved from electrocatalyst materials accelerate radical formation and subsequent chemical degradation of polymer electrolyte membrane (PEM) by the Fenton reaction [1]. Membrane degradation increases hydrogen and oxygen permeability and decreases proton conductivity and mechanical strength [2]. These phenomena significantly affect the electrochemical performance and durability of PEFCs. Therefore, in case metal oxides are used as catalyst support, it is necessary to check the dissolution of metal ions and to evaluate their effects on membranes. Our research group has been studying Nb-doped SnO2 (Sn(Nb)O2), showing improved durability of the electrocatalysts [3]. Here in this study, we evaluate the effects of Sn(Nb)O2 on the chemical degradation of PEMs. Experimental A commercial Pt/C catalyst (TEC10E50E, Tanaka Kikinzoku Kogyo, Japan) was used as the anode catalyst, while three types of cathode catalysts were applied and compared: 1) the commercial Pt/C; 2) Pt/MC where Pt was directly deposited on mesoporous carbon (MC); and 3) Pt/Sn(Nb)O2/MC where Pt was deposited on the Sn(Nb)O2 decorated on the MC. The durability test at open circuit voltage (OCV) was performed for 100 h. Before and after the durability test, cell performance, hydrogen crossover current density, and electrochemical surface area (ECSA) were characterized. The degree of membrane degradation was evaluated by measuring fluorine emission rate (FER) by ion chromatography, and membrane thickness and elemental distribution by energy-dispersive x-ray spectroscopy (EDS) coupled with field-emission scanning electron microscopy (FESEM). Results and discussion It was found that the use of Pt/Sn(Nb)O2/MC led to better durability in the OCV durability test. The decrease in OCV using Pt/Sn(Nb)O2/MC was smaller than that using Pt/C and Pt/MC, less than half of that Pt/C, as shown in Figure 1. The membrane thickness with Pt/Sn(Nb)O2/MC after the durability test was the same as that before the durability test, indicating that SnO2 actually suppressed the membrane degradation as shown in Figure 2. EDS elemental analysis confirmed no Sn ion dissolution from the cathode side as shown in Figure 3, also suggesting that SnO2 at the cathode suppressed the membrane degradation. In this presentation, we will quantitatively analyze the membrane degradation in using SnO2 and discuss possible mechanisms. Acknowledgment This paper is based on results obtained from a project, JPNP20003, commissioned by the New Energy and Industrial Technology Development Organization (NEDO). References [1] J. Zhang, F. Coms, and S. Kumaraguru, J. Electrochem. Soc., 168, 024520 (2021). [2] P. Ren, P. Pei, Y. Li, Z. Wu, D. Chen, and S. Huang, Prog. Energy Combust. Sci., 80, 100859 (2020). [3] Y. Inoue, M. Yasutake, Z. Noda, S. M. Lyth, M. Nishihara, A. Hayashi, J. Matsuda, and K. Sasaki, ECS Trans., 109 (9), 413 (2022). Figure 1
31
Simansky, Vladimir, Jan Horak, Martin Juriga et Dusan Srank. « Soil structure and soil organic matter in water-stable aggregates under different application rates of biochar ». VIETNAM JOURNAL OF EARTH SCIENCES 40, no 2 (1 juin 2018) : 97–108. http://dx.doi.org/10.15625/0866-7187/40/2/11090.
Texte intégralRésumé :
The effects of biochar and biochar combined with N-fertilizer on the content of soil organic matter in water-stable aggregates were investigated. A field experiment was conducted with different biochar application rates: B0 control (0 t ha-1), B10 (10 t ha-1) and B20 (20 t ha-1) and 0 (no N), 1st and 2nd levels of nitrogen fertilization on silt loam Haplic Luvisol (Dolna Malanta, Slovakia), in 2014. The N doses of level 1 were calculated on required average crop production using balance method. Level 2 included additional 100% of N in year 2014 and additional 50% of N in year 2016. The effects were investigated during the growing seasons of spring barley and spring wheat in 2014 and 2016, respectively. Results indicate that the B20N2 treatment significantly increased the proportion of water-stable macro-aggregates (WSAma) and reduced water-stable micro-aggregates (WSAmi). Aggregate stability increased only in the B20N1 treatment. The B20N2 treatment showed a robust decrease by 27% in the WSAma of 0.5-0.25 mm. On the other hand, an increase by 56% was observed in the content of WSAma with fractions 3-2 mm compared to the B0N0 treatment. The effect of N fertilizer on WSAma was confirmed only in the case of the B10N2 treatment. The proportion of WSAma with fractions 3-2 mm decreased by 42%, while the size fraction of 0.5-0.25 mm increased by 30% compared to the B10N0 treatment. The content of WSAma with fractions 1-0.5 mm decreased with time. On the contrary, the content of WSAma with particle sizes above 5 mm increased with time in all treatments except the B10N2 and B20N2 treatments. A statistically significant trend was identified in the proportion of WSA in the B10N2 and B20N2 treatments, which indicates that biochar with higher application levels of N fertilizer stabilizes the proportion of water-stable aggregates. In all treatments, the content of soil organic carbon (SOC) and labile carbon (CL) in WSAmi was lower than those in WSAma. A considerable decrease of SOC in the WSAma >5 mm and an increase of SOC in WSAmi were observed when biochar was applied at the rate of 10 t ha-1. Contents of SOC in WSAmi increased as a result of adding biochar combined with N fertilizer at first level. CL in WSA significantly increased in all size fractions of WSA.References Abiven S., Hund A., Martinsen V., Cornelissen G., 2015. Biochar amendment increases maize root surface areas and branching: a shovelomics study in Zambia. Plant Soil, 342, 1-11. Agegnehu G., Bass A.M., Nelson P.N., and Bird M.I., 2016. Benefits of biochar, compost and biochar–compost for soil quality, maize yield and greenhouse gas emissions in a tropical agricultural soil. Sci. Tot. Environ., 543, 295-306. Angers D.A., Samson N., Legere A., 1993. Early changes in water-stable aggregation induced by rotation and tillage in a soil under barley production. Can. J. Soil Sci., 73, 51-59. Atkinson Ch.J., Fitzgerald J.D., Hipps N.A., 2010. Potential mechanisms for achieving agricultural benefits from biochar application to temperate soils: a review. Plant Soil, 337, 1-18. Balashov E., Buchkina N., 2011. Impact of short- and long-term agricultural use of chernozem on its quality indicators. Int. Agrophys., 25, 1-5. Barrow C.J., 2012. Biochar: potential for countering land degradation and for improving agriculture. Appl. Geogr., 34, 21-28. Barthes B.G., Kouakoua E.T., Larre-Larrouy M.C., Razafimbelo T.M., De Luca E.F., Azontonde A., Neves C.S.V.J., De Freitas P.L., Feller C.L., 2008. Texture and sesquioxide effects on water-stable aggregates and organic matter in some tropical soils. Geoderma, 143, 14-25. Benbi D.K., Brar K., Toor A.S., Sharma S., 2015. Sensitivity of labile soil organic carbon pools to long-term fertilizer, straw and manure management in rice-wheat system. Pedosphere, 25, 534-545. Benbi D.K., Brar K., Toor A.S., Singh P., Singh H., 2012. Soil carbon pools under poplar-based agroforestry, rice-wheat, and maize-wheat cropping systems in semi-arid India. Nutr. Cycl. Agroecosys., 92, 107-118. Blanco-Canqui H., Lal L., 2004. Mechanisms of carbon sequestration in soil aggregates. Crit. Rev. Plant Sci., 23, 481-504. Brevik E.C., Cerda A., Mataix-Solera J., Pereg L., Quinton J.N., Six J., Van Oost K., 2015. The interdisciplinary nature of SOIL. SOIL, 1, 117-129. Brodowski S., John B., Flessa H., Amelung W., 2006. Aggregate-occluded black carbon in soil. Eur. J. Soil Sci., 57, 539-546. Bronick C.J., Lal R., 2005. The soil structure and land management: a review. Geoderma, 124, 3-22. Chenu C., Plante A., 2006. Clay-sized organo-mineral complexes in a cultivation chronosequece: revisiting the concept of the “primary organo-mineral complex”. Eur. J. Soil Sci., 56, 596-607. Dziadowiec H., Gonet S.S., 1999. Methodical guide-book for soil organic matter studies. Polish Society of Soil Science, Warszawa, 65p. Elliott E.T., 1986. Aggregate structure and carbon, nitrogen, and phosphorus in native and cultivated soils. Soil Sci. Soc. Am. J., 50, 627-633. Fischer D., Glaser B., 2012. Synergisms between compost and biochar for sustainable soil amelioration, In: Kumar S. (ed.): Management of Organic Waste, In Tech Europe, Rijeka, 167-198. Glaser B., Lehmann J., Zech W., 2002. Ameliorating physical and chemical properties of highly weathered soils in the tropics with charcoal - a review. Biol. Fertil. Soils., 35, 219-230. Heitkotter J., and B. Marschner, 2015. Interactive effects of biochar ageing in soils related to feedstock, pyrolysis temperature, and historic charcoal production. Geoderma, 245-246, 56-64. Herath H.M.S.K., Camps-Arbestain M., Hedley M., 2013. Effect of biochar on soil physical properties in two contrasting soils: an Alfisol and an Andisol. Geoderma, 209-210, 188-197. Hillel D., 1982, Introduction to soil physics. Academic Press, San Diego, CA , 364 p. Chenu C., Plante A., 2006. Clay-sized organo-mineral complexes in a cultivation chronosequence: revisiting the concept of the “primary organo-mineral complex”. Eur. J. Soil Sci., 56, 596-607. IUSS Working Group WRB., 2014. World reference base for soil resources 2014. International soil classification system for naming soils and creating legends for soil maps. World Soil Resources Reports, 106, FAO, Rome., 112p. Jeffery S., Verheijen F.G.A., Van der Velde M., Bastos A.C., 2011. A quantitative review of the effects of biochar application to soils on crop productivity using meta-analysis. Agr. Ecosys. Environ., 144, 175-187. Jien S.H., Wang Ch.S., 2013. Effects of biochar on soil properties and erosion potential in a highly weathered soil. Catena, 110, 225-233. Kammann C., Linsel S., Goßling J., Koyro H.W., 2011. Influence of biochar on drought tolerance of Chenopodium quinoa Willd and on soil-plant relations. Plant Soil, 345, 195-210. Kodesova R., Nemecek K., Zigova A., Nikodem A., Fer M., 2015. Using dye tracer for visualizing roots I pact on soil structure and soil porous system. Biologia, 70, 1439-1443. Krol, A., Lipiec, J., Turski, M., J. Kuoe, 2013. Effects of organic and conventional management on physical properties of soil aggregates. Int. Agrophys., 27, 15-21. Kurakov A.V., Kharin S.A., 2012. The Formation of Water-Stable Coprolite Aggregates in Soddy-Podzolic Soils and the Participation of Fungi in This Process. Eur. Soil Sci., 45, 429-434. Loginow W., Wisniewski W., Gonet S.S., Ciescinska B., 1987. Fractionation of organic carbon based on susceptibility to oxidation. Pol. J. Soil Sci., 20, 47-52. Lynch, J.M., and E. Bragg, 1985. Microorganisms and soil aggregate stability. Adv. Soil Sci., 2, 133-171. MHYPERLINK "about:blank"unkholm L.J., Schjonning P., Debosz K., Jensen H.E., Christensen B.T., 2002. Aggregate strength and mechanical behaviour of a sandy loam soil under long-term fertilization treatments. Eur. J. Soil Sci., 53, 129-137. Paradelo R., Van Oort F., Chenu C., 2013. Water-dispersible clay in bare fallow soils after 80 years of continuous fertilizer addition. Geoderma, 200-201, 40-44. Purakayastha T.J., Kumari S., Pathak H., 2015. Characterisation, stability, and microbial effects of four biochars produced from crop residues. Geoderma, 239-240, 293-303. Rees F., Germain C., Sterckeman T., Morel J.L., 2015. Plant growth and metal uptake by a non-hyperaccumulating species (Lolium perenne) and a Cd-Zn hyperaccumulator (Noccaea caerulescens) in contaminated soils amended with biochar. Plant Soil, 395, 57-73. Saha D., Kukal S.S., Sharma S., 2011. Land use impacts on SOC fractions and aggregate stability in typic Ustochrepts of Northwest India. Plant Soil, 339, 457-470. Six J., Bossuyt H., Degryze S., Denef K., 2004. A history of research on the link between (micro)aggregates, soil biota, and soil organic matter dynamics. Soil Till. Res., 79, 7-31. Six J., Elliott E.T., Paustian K., 2000. Soil macroaggregate turnover and microaggregate formation: A mechanism for C sequestration under no-tillage agriculture. Soil Biol. Biochem., 32, 2099-2103. Soinne H., Hovi J., Tammeorg P., Turtola E., 2014. Effect of biochar on phosphorus sorption and clay soil aggregate stability. Geoderma, 219-220, 162-167. Simansky V., 2013. Soil organic matter in water-stable aggregates under different soil management practices in a productive vineyard. Arch. Agron. Soil Sci., 59(9), 1207-1214. Simansky V., Jonczak J., 2016. Water-stable aggregates as a key element in the stabilization of soil organic matter in the Chernozems. Carp. J. Earth Environ. Sci., 11, 511-517. Simon T., Javurek M., Mikanova O., Vach M., 2009. The influence of tillage systems on soil organic matter and soil hydrophobicity. Soil Till, Res., 105, 44-48. Tiessen H., Stewart J.W.B., 1988. Light and electron microscopy of stainedmicroaggregates: the role of organic matter and microbes in soil aggregation. Biogeochemistry, 5, 312-322. Tisdall J.M., Oades J.M., 1980. The effect of crop rotation on aggregation in a red-brown earth. Austr. J. Soil Res., 18, 423-433. Vadjunina A.F., Korchagina Z.A., 1986. Methods of Study of Soil Physical Properties. Agropromizdat, Moscow, 415p. Vaezi A.R., Sadeghi S.H.R., Bahrami H.A., Mahdian M.H., 2008. Modeling the USLE K-factor for calcareous soils in northwestern Iran. Geomorphology, 97, 414-423. Von Lutzow M., Kogel-Knabner I., Ekschmitt K., Matzner E., Guggenberger G., Marschner B., Flessa H., 2006. Stabilization of organicmatter in temperate soils:mechanisms and their relevance under different soil conditions a review. Eur. J. Soil Sci., 57, 426-445.
32
Faust, Johan C., Philippa Ascough, Robert G. Hilton, Mark Stevenson, Katharine R. Hendry et Christian März. « New evidence for preservation of contemporary marine organic carbon by iron in Arctic shelf sediments ». Environmental Research Letters, 30 novembre 2022. http://dx.doi.org/10.1088/1748-9326/aca780.
Texte intégralRésumé :
Abstract The protection of organic carbon through association with iron minerals (FeR) is an important factor in its stabilisation, long-term storage, and burial efficiency in marine sediments. However, large uncertainties still exist concerning the sources, lability, age, and composition of the organic matter associated with FeR in natural sediments. Therefore, the timing and environmental setting of the carbon-iron bonding process remain elusive. Here we use radiocarbon (Δ14C) and stable isotopes (δ13C) of downcore bulk sedimentary organic matter, benthic foraminifera and the organic carbon fraction bound to FeR to interrogate the source and age of the organic carbon pool associated with FeR in Arctic marine sediments. In the Barents Sea, we find that the organic carbon associated with FeR is younger overall than the bulk organic matter and is probably marine derived. The comparison to other investigations of OC-FeR origins reveals that in large parts of Arctic shelf regions FeR associated organic carbon is radiocarbon enriched and has a higher δ13Corg value compared to the bulk sediment, irrespective of sediment depth/age. Our findings suggest a rapid and preferential binding of fresh and marine organic matter with FeR. Hence, labile organic matter prone to decomposition is protected and stabilised, underlining the potential of the organic carbon-iron association as an efficient carbon burial mechanism.
33
Saikrithika, Sairaman, Jayaraj Premkumar, Desikan Rajagopal., Yun Suk Huh et Annamalai Senthil Kumar. « In Situ Electro-organic Synthesis and Functionalization of Catechol Derivative on Carbon Black and Its Interference-free Voltammetric pH Sensor Application ». Journal of The Electrochemical Society, 28 février 2023. http://dx.doi.org/10.1149/1945-7111/acbfe5.
Texte intégralRésumé :
Abstract We report an easy electrochemical route for preparing a catechol derivative (di-ferulyl sesamol derivative, designated as CA-Fer) functionalized low-cost carbon black (CB) modified electrode in a neutral pH buffer solution. As synthesized precursor organic compound, CA-Fer has been electrochemically oxidized over the CB by potential cycling treatment in pH 7 PBS that leads to a high redox active CA-Fer-catechol derivative (CB@CA-Fer-Redox), which exhibited a well-defined and stable surface-confined redox response at Eo’ = 0.150 V vs Ag/AgCl with a surface excess value = 50.46 nmol cm−2. Unlike the conventional redox active mediators, GCE/CB@CA-Fer-Redox modified electrode has failed to show any mediated oxidation/reduction response to various electro-active biochemicals and chemicals, viz., ascorbic acid, glucose, cysteine, caffeic acid, hydrazine, hydrogen peroxide, uric acid, dopamine, creatinine, urea, nitrite, sulfide and sulfate ions, depicting a clear advantage of using it as a voltammetric pH sensor for real-time applications. The modified electrode showed a linear voltammetric potential signal against pH in a window, 3-11, with a slope value of (∂Ep/∂pH) = -59±3 mV pH-1. As an independent study, a CA-Fer-Redox modified three-in-one screen printed electrode was developed, and a sensitive voltammetric pH analysis of some chemical biochemical real sample systems were demonstrated.
34
Zhang, Zhuoyue, Ming Lu, Chenglong Wang, Chuchu Zhang, Bingying Lin, Qihang Liao, Penghua Qiu et Xinqing Zou. « Divergent Responses of Organic Carbon to Sedimentary Environment Transformation in a River‐Dominated Marginal Sea ». Journal of Geophysical Research : Biogeosciences 129, no 11 (30 octobre 2024). http://dx.doi.org/10.1029/2024jg008034.
Texte intégralRésumé :
AbstractThe fate of organic carbon (OC) in most river‐dominated ocean margins (RiOMars) has undergone a noticeable transformation with the increased sediment retention engineering in watersheds. In the East China Sea (ECS), transformation in sediment and the influence of bulk OC have been broadly studied. However, the response of different mechanisms of OC protection under transformation has not been investigated, hindering our understanding of the factors that control OC deposition. In this study, we isolated different OC fractions, analyzed the basic parameters of the sediments, and compared the previous study's data to reveal how OC deposition responded to transformation. Our research indicates that transformation leads to the reduction of OC associated with minerals and sorting of OC occluded by plant debris and OC associated with minerals resulting in increased decomposition and mineralization of OC. The transformation affects the mechanism of OC binding with reactive iron (FeR), increasing FeR‐protected OC content. Still, the co‐precipitation mechanism and the intense redox environment in the mud deposit decrease the FeR‐protected OC stability. Taken together, the impact of transformation is to increase the risk of OC decomposition and to weaken the OC preservation ability in RiOMars as carbon sinks. This study has implications for river‐dominated passive margins subject to increased sediment retention engineering in watersheds worldwide and deserves more attention.
35
Metherell, A. K. « Management effects on soil carbon storage in New Zealand pastures ». Proceedings of the New Zealand Grassland Association, 1 janvier 2003, 259–64. http://dx.doi.org/10.33584/jnzg.2003.65.2494.
Texte intégralRésumé :
The amount of soil carbon is the net effect of carbon inputs and decomposition and is influenced by many factors including the level of herbage utilisation, root production, litter quality, soil fertility and soil moisture status. Long term experiments at Winchmore, in mid- Canterbury, show soil carbon levels increased after initial development, but after 50 years fertiliser input has had no net effect on soil carbon, while increasing the frequency of irrigation has actually resulted in lower soil carbon levels. Pasture development at Ballantrae , in the southern Hawke's Bay, has been associated with a decline in soil C levels, with the high fertility treatment having only slightly higher soil C than the treatment receiving a lower rate of fertiliser. At Tara Hills, in South Island semi-arid high country, increased stocking rate is associated with a decrease in soil C. Contrary to common perceptions increases in pasture and farm productivity do not necessarily result in increased soil carbon storage. Keywords: carbon, fer tiliser, grazing management, irrigation, soil organic matter
36
Muramiya, Yusuke, Hidekazu Yoshida, Nagayoshi Katsuta, Ryusei Kuma et Tomoyuki Mikami. « Ammonite concretion formation through organic decomposition in the iron reduction zone ». Journal of Sedimentary Research, 13 novembre 2023. http://dx.doi.org/10.2110/jsr.2023.078.
Texte intégralRésumé :
The ammonites in spherical carbonate concretions often preserve their original three-dimensional (3D) shell shapes and detailed fragile structures. However, the formation process of spherical ammonite concretion is not fully understood. Herein, the ammonite concretions identified in the Cretaceous (Campanian) Osoushinai Formation, Yezo Group, Japan, are examined to understand their formation process during the soft tissue decomposition after burial in marine sediments. In the Osoushinai Formation, almost all observed ammonites in concretions preserve their 3D form without phragmocone deformation. The calcite filling in the remaining body chamber of ammonites (BC1) shows that shells were buried with soft tissues. These occurrences, negative delta13C values, and the near-zero delta18O values of BC1 as well as the concretions indicate that both BC1 and concretions rapidly formed from dissolved inorganic carbon derived from organic matter, including the soft tissue of dead organisms, in the shallow part of the sediments. The increasing Fe concentration in BC1 shows that BC1 formed in the iron reduction (FeR) zone, where organic matter was decomposed owing to the activity of iron-reducing microorganisms. The similarity of the elemental and isotopic compositions of BC1 and concretions show that they concurrently formed in the FeR zone. In the Osoushinai Formation, an abundant influx of Fe(III) and intense bioturbation during the deposition of the formation promoted organic decomposition in the FeR zone, causing rapid formation of BC1 and concretions. Such rapidly formed calcite fillings and concretions protected fossils from deformation and dissolution during diagenesis to preserve their 3D form. Overall, the findings of this study provide a new insight into the relation between sedimentary environments and the fossil preservation process via rapid concretion formation.
37
Zhao, Tianming, Zihan Yu, Lei Zhou, Xiaoyu Wang, Yangyang Hui, Lihong Mao, Xiaofei Fan, Bangmao Wang, Xingliang Zhao et Chao Sun. « Regulating Nrf2-GPx4 axis by bicyclol can prevent ferroptosis in carbon tetrachloride-induced acute liver injury in mice ». Cell Death Discovery 8, no 1 (7 septembre 2022). http://dx.doi.org/10.1038/s41420-022-01173-4.
Texte intégralRésumé :
AbstractHepatocellular death is a sensitive parameter for detecting acute liver injury (ALI) of toxic, viral, metabolic, and autoimmune origin. Ferroptosis has recently been implicated in carbon tetrachloride (CCl4)-induced ALI. However, the underpinning mechanism and mechanistic basis remain elusive. In this study, bicyclol, a proprietary hepatoprotectant in China, and ferroptosis-specific inhibitor ferrostatin-1 (Fer-1) were administered in CCl4-injured mice. A panel of ferroptosis-related markers, including mitochondria morphology, reactive oxygen species production, protein adducts in response to lipid peroxidation, and key modulators of ferroptotic process, was determined in vivo. Erastin-treated L-O2 hepatocytes were transfected with glutathione peroxidase 4 (GPx4) or nuclear factor erythroid 2-related factor 2 (Nrf2) siRNA to delineate the pathway of bicyclol against ferroptosis in vitro. As a result, CCl4 led to iron accumulation, excessive reactive oxygen species production, enhanced lipid peroxidation, and characteristic morphological changes in mitochondria, along with a decrease in GPx4 and xCT protein levels in ALI mice liver, all of which were generally observed in ferroptosis. The use of Fer-1 further corroborated that ferroptosis is responsible for liver damage. Bicyclol exerted its hepatoprotection by preventing the aforesaid ferroptotic process. Furthermore, bicyclol alleviated erastin-induced cellular inviability, destruction, and lipid peroxidation in vitro. Knockdown of GPx4 diminished these protective activities against perturbations associated with ferroptosis in L-O2 hepatocytes. Additionally, Nrf2 silencing drastically reduced GPx4 levels, and further impeded the medicinal effects of bicyclol. In summary, positively regulating Nrf2-GPx4 axis by bicyclol can prevent ferroptosis in CCl4-induced ALI in mice.
38
Nageswari, P., A. K. Verma, Subodh Gupta et A. Jeyakumari. « Finger millet as a carbon source for biofloc, improved growth performance of Pangasianodon hypophthalmus (Sauvage, 1878) fingerlings ». Indian Journal of Fisheries 67, no 4 (31 décembre 2020). http://dx.doi.org/10.21077/ijf.2020.67.4.98872-07.
Texte intégralRésumé :
A 90-days experiment was conducted to investigate the effects of biofloc produced with different carbon sources on growth performances, survival and body indices of Pangasianodon hypophthalmus fingerlings (average body weight: 6.4±0.05 g). The different carbon sources used in the experiment employing biofloc technology (BFT) were BFT-T (tapioca), BFT-S (sorghum), BFT-PM (pearl millet), BFT-FM (finger millet) and clear water with no addition of carbon source was treated as control. At the end of the experiment, significantly (p<0.05) higher weight gain (24.34±0.50 g), Specific growth rate, SGR (1.37±0.02% day-1); Feed efficiency ratio, FER (0.47±0.01); Protein efficiency ratio, PER (1.47±0.03) and lower Feed conversion ratio, FCR (2.12±0.03) were witnessed in the group where finger millet was used as a carbon source (BFTFM) and significantly lower responses were noticed in the control (CW). Results showed that there were no significantdifferences (p>0.05) in hepatosomatic index and viscerosomatic index of fish between the different experimental groups. During the termination of the experiment, no mortality was seen among the different experimental groups. Based on the results acquired from this study, finger millet could be used as an ideal carbon source for biofloc to augment the growth and productivity of P. hypophthalmus under farming.
39
Song, Inhak, Iskra Z. Koleva, Hristiyan A. Aleksandrov, Linxiao Chen, Jaeyoung Heo, Dongsheng Li, Yong Wang, János Szanyi et Konstantin Khivantsev. « Ultrasmall Pd Clusters in FER Zeolite Alleviate CO Poisoning for Effective Low-Temperature Carbon Monoxide Oxidation ». Journal of the American Chemical Society, 7 décembre 2023. http://dx.doi.org/10.1021/jacs.3c08916.
Texte intégral
40
Yi, Jiazhi, Shuyun Wu, Siwei Tan, Yunfei Qin, Xing Wang, Jie Jiang, Huiling Liu et Bin Wu. « Berberine alleviates liver fibrosis through inducing ferrous redox to activate ROS-mediated hepatic stellate cells ferroptosis ». Cell Death Discovery 7, no 1 (décembre 2021). http://dx.doi.org/10.1038/s41420-021-00768-7.
Texte intégralRésumé :
AbstractBerberine (BBR) has been explored as a potential anti-liver fibrosis agent, but the underlying mechanisms are unknown. In the current study, we aimed to investigate the molecular mechanisms underlying the effect of BBR against liver fibrogenesis in thioacetamide (TAA) and carbon tetrachloride (CCl4) induced mouse liver fibrosis. In addition to i.p. injection with TAA or CCl4, mice in the treatment group received BBR intragastrically. Concurrently, combined with TAA and BBR treatment, mice in the inhibitor group were injected i.p. with ferrostatin-1 (Fer-1). Hepatic stellate cells (HSCs) were also used in the study. Our results showed that BBR obviously alleviated mouse liver fibrosis and restored mouse liver function; however, the pharmacological effects of BBR against liver fibrosis were significantly diminished by Fer-1 treatment. Mechanically, BBR impaired the autophagy–lysosome pathway (ALP) and increased cell reactive oxygen species (ROS) production in HSCs. ROS accelerated the breakdown of the iron-storage protein ferritin and sped up iron release from ferritin, which resulted in redox-active iron accumulation in HSCs. Lipid peroxidation and glutathione (GSH) depletion triggered by the Fenton reaction promoted ferroptosis and attenuated liver fibrosis. Furthermore, impaired autophagy enhanced BBR-mediated ferritin proteolysis to increase cellular ferrous overload via the ubiquitin–proteasome pathway (UPS) in HSCs and triggered HSC ferroptosis. Collectively, BBR alleviated liver fibrosis by inducing ferrous redox to activate ROS-mediated HSC ferroptosis. Our findings may be exploited clinically to provide a potential novel therapeutic strategy for liver fibrosis.
41
Mohan, Karishma, et Prashant S. Phale. « Carbon Source-Dependent Inducible Metabolism of Veratryl Alcohol and Ferulic Acid in Pseudomonas putida CSV86 ». Applied and Environmental Microbiology 83, no 8 (10 février 2017). http://dx.doi.org/10.1128/aem.03326-16.
Texte intégralRésumé :
ABSTRACT Pseudomonas putida CSV86 degrades lignin-derived metabolic intermediates, viz., veratryl alcohol, ferulic acid, vanillin, and vanillic acid, as the sole sources of carbon and energy. Strain CSV86 also degraded lignin sulfonate. Cell respiration, enzyme activity, biotransformation, and high-pressure liquid chromatography (HPLC) analyses suggest that veratryl alcohol and ferulic acid are metabolized to vanillic acid by two distinct carbon source-dependent inducible pathways. Vanillic acid was further metabolized to protocatechuic acid and entered the central carbon pathway via the β-ketoadipate route after ortho ring cleavage. Genes encoding putative enzymes involved in the degradation were found to be present at fer, ver, and van loci. The transcriptional analysis suggests a carbon source-dependent cotranscription of these loci, substantiating the metabolic studies. Biochemical and quantitative real-time (qRT)-PCR studies revealed the presence of two distinct O-demethylases, viz., VerAB and VanAB, involved in the oxidative demethylation of veratric acid and vanillic acid, respectively. This report describes the various steps involved in metabolizing lignin-derived aromatic compounds at the biochemical level and identifies the genes involved in degrading veratric acid and the arrangement of phenylpropanoid metabolic genes as three distinct inducible transcription units/operons. This study provides insight into the bacterial degradation of lignin-derived aromatics and the potential of P. putida CSV86 as a suitable candidate for producing valuable products. IMPORTANCE Pseudomonas putida CSV86 metabolizes lignin and its metabolic intermediates as a carbon source. Strain CSV86 displays a unique property of preferential utilization of aromatics, including for phenylpropanoids over glucose. This report unravels veratryl alcohol metabolism and genes encoding veratric acid O-demethylase, hitherto unknown in pseudomonads, thereby providing new insight into the metabolic pathway and gene pool for lignin degradation in bacteria. The biochemical and genetic characterization of phenylpropanoid metabolism makes it a prospective system for its application in producing valuable products, such as vanillin and vanillic acid, from lignocellulose. This study supports the immense potential of P. putida CSV86 as a suitable candidate for bioremediation and biorefinery.
42
Mok, Jin-Sook, Ayeon Choi, Bomina Kim, Sung-Uk An, Won-Chan Lee, Hyung Chul Kim, Jonguk Kim, Cheolho Yoon et Jung-Ho Hyun. « Phosphorus Dynamics Associated With Organic Carbon Mineralization by Reduction of Sulfate and Iron in Sediment Exposed to Fish Farming ». Frontiers in Marine Science 8 (21 septembre 2021). http://dx.doi.org/10.3389/fmars.2021.645449.
Texte intégralRésumé :
The expansion of the aquaculture industry has resulted in accumulation of phosphorus (P)-rich organic matter via uneaten fish feed. To elucidate the impact of fish farming on P dynamics, P speciation, and benthic P release along with partitioning of organic carbon (Corg) mineralization coupled to sulfate reduction (SR) and iron reduction (FeR) were investigated in the sediments from Jinju Bay, off the southern coast of South Korea, in July 2013. SR in the farm sediment was 6.9-fold higher than the control sediment, and depth-integrated (0–10 cm) concentrations of NH4+, PO43–, and H2S in pore water of the farm sediment were 2.2-, 3.3-, and 7.4-fold higher than that in control sediment, respectively. High biogenic-P that comprised 28% of total P directly reflected the impact of P-rich fish feed, which ultimately enhanced the bioavailability (58% of total P) of P in the surface sediment of the farm site. In the farm sediment where SR dominated Corg mineralization, H2S oxidation coupled to the reduction of FeOOH stimulated release of P bound to iron oxide, which resulted in high regeneration efficiency (85%) of P in farm sediments. Enhanced P desorption from FeOOH was responsible for the increase in authigenic-P and benthic P flux. Authigenic-P comprised 33% of total P, and benthic P flux to the overlying water column accounted for approximately 800% of the P required for primary production. Consequently, excessive benthic P release resulting directly from oversupply of P-rich fish feed was a significant internal source of P for the water column, and may induce undesirable eutrophication and harmful algal blooms in shallow coastal ecosystems.
43
« Research on College Students' Awareness Level for Low-carbon Campuses Development under Dual Carbon Goal ». Frontiers in Educational Research 7, no 2 (2024). http://dx.doi.org/10.25236/fer.2024.070225.
Texte intégral
44
Zheng, Jichang, Wencong Zhang, Zhijie Dan, Yanwen Zhuang, Yongtao Liu, Kangsen Mai et Qinghui Ai. « Replacement of dietary fish meal with Clostridium autoethanogenum meal on growth performance, intestinal amino acids transporters, protein metabolism and hepatic lipid metabolism of juvenile turbot (Scophthalmus maximus L.) ». Frontiers in Physiology 13 (24 août 2022). http://dx.doi.org/10.3389/fphys.2022.981750.
Texte intégralRésumé :
Clostridium autoethanogenum meal (CAM) is a novel single-cell protein, which is produced from bacteria using carbon monoxide (CO) as sole carbon source. To evaluate the efficiency of CAM as an alternative for dietary fish meal, a 56-days growth experiment was performed on juvenile turbot (Scophthalmus maximus L.) with initial average weight of 9.13 ± 0.02 g. Six iso-nitrogenous (crude protein, 51.0%) and iso-lipidic (crude lipid, 11.5%) diets were formulated with 0%, 15%, 30%, 45%, 60% and 80% dietary fish meal protein substituted by CAM protein, which were designated as CAM0 (the control group), CAM15, CAM30, CAM45, CAM60 and CAM80, respectively. Results showed that no significant differences were observed in survival rate (over 97.50%) among different dietary treatments (p > 0.05). The specific growth rate (SGR) was not significantly affected when replacement levels of dietary fish meal with CAM were less than 45% (p > 0.05). The feed intake (FI) was significantly linear reduced with increasing dietary CAM (p < 0.05), whereas no significant differences were observed in feed efficiency ratio (FER), protein efficiency ratio (PER) and protein retention (PR) among different dietary treatments (p > 0.05). With increasing dietary CAM, lipid retention (LR) and carcass lipid tended to be increased in both significantly linear and quadratic patterns (p < 0.05). The apparent digestibility coefficient (ADC) of crude protein and some essential amino acids, including threonine, valine, lysine, histidine and arginine, showed significantly linear increase with increasing dietary CAM (p < 0.05). Furthermore, with the increase of dietary CAM, the gene expression of intestinal peptide and amino acids transporters was first up-regulated and then down-regulated with significantly quadratic pattern (p < 0.05), peaking in fish fed with diets CAM30 or CAM45, which was similar to the expression of genes related protein degradation in muscle. For genes related to protein metabolism in liver and muscle, the expression of mammalian target of rapamycin (mtor) was not significantly affected by dietary CAM, while the general control nonderepressible 2 (gcn2) tended to be first up-regulated and then down-regulated with significantly quadratic pattern (p < 0.05). Apart from that, the lipid metabolism of turbot was also affected by high dietary CAM, evidenced by increased expression of hepatic genes related to lipogenesis as well as reduced expression of genes related to lipid oxidation and lipid transport. In conclusion, CAM can replace up to 45% fish meal protein in diet for juvenile turbot without significantly adverse effects on growth performance. But excessive dietary CAM would result in significant growth reduction, and excessive lipid deposition may also occur in fish fed diets with high levels of CAM.
45
Silaev, Andrei L., et Evgeny V. Smolsky. « ¹³⁷Cs migration in the floodplain ecosystem of the Unecha river ». Land Reclamation and Hydraulic Engineering 13, no 2 (2023). http://dx.doi.org/10.31774/2712-9357-2023-13-2-228-241.
Texte intégralRésumé :
Purpose: to study the ¹³⁷Cs migration and concentration in the alluvial soils profile and the radionuclide transfer to plants in the river Unecha floodplain ecosystem. Materials and methods. Field studies were carried out in 2019–2021 in Bryansk region (Klintsovsky district, the village of Lopatni, the right bank of the river Unecha, the current reclamation system). The density of ¹³⁷Cs contamination of the territory after the Chernobyl accident was 185–555 kBq/m². Conjugated soil and plant samples were taken in various sub-systems of the floodplain (near-channel, central, near-terrace). Agrochemical indicators of fer-tility and ¹³⁷Cs specific activity in soil and plants were determined using generally accepted laboratory methods. Results. A strong variability of the agrochemical parameters of alluvial soils in layers every 5 cm within 0–20 cm was determined. A high content of mobile phos-phorus and a low content of potassium, a strongly acid reaction of the environment, and a ten-dency to the growth in the organic carbon content from the near-channel to near-terraсе floodplain subsystem was found. The ¹³⁷Cs horizontal distribution in the river Unecha flood-plain soils was determined by soil genesis of the floodplain subsystems; the maximum specific activity of ¹³⁷Cs 3953 Bq/kg was found in the near-terrace part of the floodplain. The ¹³⁷Cs maximum concentration was found in the near-channel and central subsystem in the soil layer of 0–5 cm, and in the near-terrace subsystem in the layer of 5–10 cm. In the floodplain of the river Unecha, the ¹³⁷Cs coefficient transfer from soil to plants decreases from the central to the near-channel and near-terrace. Conclusions. The formation of agrochemical indicators of al-luvial soil fertility and the ¹³⁷Cs vertical distribution is determined by soil genesis in floodplain subsystems; it can be uniformly decreasing or concentrated in separate layers at biochemical barriers. In the floodplain ecosystem, the ¹³⁷Cs concentration in the 0–20 cm layer increases from the near-channel to near-terrace subsystem. Forage production under the conditions of radioactive contamination of the near-river and central parts of the floodplain is possible without the use of protective measures.
46
« Integration and practice of ideological political elements in civil engineering management courses under the carbon peak and carbon neutrality goals in China ». Frontiers in Educational Research 6, no 13 (2023). http://dx.doi.org/10.25236/fer.2023.061316.
Texte intégral
47
« Reforming and innovating the talent development model for international cooperation program in engineering management under the carbon peak and carbon neutrality goals in China ». Frontiers in Educational Research 7, no 4 (2024). http://dx.doi.org/10.25236/fer.2024.070410.
Texte intégral
48
« The Role and Challenge of Dual Carbon Goals in Promoting Electric Power Education : Exploring the Path of Integrating Renewable Energy and Low Carbon Technology ». Frontiers in Educational Research 6, no 24 (2023). http://dx.doi.org/10.25236/fer.2023.062407.
Texte intégral
49
« Course construction and practice of water pollution control engineering in the background of carbon neutralization ». Frontiers in Educational Research 6, no 7 (2023). http://dx.doi.org/10.25236/fer.2023.060715.
Texte intégral
50
PURSHOTTAM KUMAR, J. P. AGARWAL et B.R. SOOD. « Effect inoculation, nitrogen and phosphorus on lentil (Lens culinaris) ». Indian Journal of Agronomy 40, no 3 (10 octobre 2001). http://dx.doi.org/10.59797/ija.v40i3.3837.
Texte intégralRésumé :
A field experiment was conducted at the root length, fresh and dry weights of root R.M.P. College, Gurukul-Narsan, Hardwar, only at ldtq stages of the growth. Applica- during the winter season of 1989-90. The tion of 20 kgaN1ha resulted in a significant experimental soil was loam in texture, increase in root h g t h at harvest over no ap- medium in available nitrogen (380 kg NI plication. ha), rnedium in organic carbon (0.7%), high Similarly, fresh afid dry weights of root at in available phosphorus (40 kg Plha) and 90 days after sowing ang at harvest were potassium (370 kg Wha) and neutral in also improved significantly with N applica- reaction (pH 6.8). Sixteen treatments tion, indicating the importance of starter N . -_ - % consisting of 2 levels of inoculation dose in legumes which had increased the ac- (uninoculated and inoculated with a tivity of bacteria in the later stages. The rhizobium culture), 2 levels of nitrogen (0 grain yield was significantly higher in 20 kg and 20 kg Nlha) and 4 levels of phosphorus Nha treatment than the control. Similar re- (25, 50, 75 and 100 kg P205/ha) were tried sults were reported by Mohamed (1978) in randomized block design, replicated 3 also. times. Full quantity of N and P was applied The response to phosphorus was observed at the time of sowing. The lentil variety T up to 50 kg P2051ha for root length at har- 36 was sown in rows at 25 cm apart on 15 vest and for fresh and dry weights at 90 days October 1989 and was harvested on 15 and at harvest. Negative response beyond 50 March 1990. kg P205/ha indicated that higher level of P *- -- Most of the root parameters improved was not found useful which might have been significantly by the inoculation. Root length, due to nutrient imbalance in soil-plant-sys- number of nodules, fresh and dry weights of tem. Grain yield of lentil increased signifi- rootslplant increased significantly by inocu- cantly up to 50 kg P205/ha and thereafter lation, which may be ascribed to better nod- decreased significantly. Singh and Singh ulation of roots and its culminatiorl in more (1 991) also observed similar effect of P fer- nitrogen fixation that inturns had a signifi- tilization in lentil. cant effect on the grain yield (Table 1).Mai- Thus for getting higher yield from the ti et al. (1988) also obtained higher grain lentil seed may be inoculated with yield of lentil due to inoculation practice. rhizobium culture and crop may be fertilized . , Application of 20 kg Nha influenced the with 20 kg N and 50 kg P205ha. --