Papers by Keyword: Carbon

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Authors: N.Yu. Arutyunov, V.Yu. Trashchakov
Authors: Hideto Oyama, Soichiro Kojima, Kousuke Ono, Yoshimasa Ito
Authors: James P. Bennett, Kyei Sing Kwong, Hugh Thomas, Rick Krabbe
Abstract: Gasification is used by industry to convert low cost carbon into materials for producing electricity and chemical products such as fertilizer, plastics, and Fischer-Tropsch liquids. It is considered a critical technology in the success of the DOE’s Near Zero Emissions Advanced Fossil Fuel Power Plants, could play a key role in defining long-term energy security in both power and liquid fuels, and is considered a leading candidate for H2 production in a hydrogen based economy. Molten slag originating from mineral impurities in the carbon feedstock is of concern to slagging gasifier operation, with some gasifiers generating over 100 tons per day. Molten slag attacks and wears away the internal lining of the gasifier vessel by two major mechanisms, chemical dissolution and spalling. The main component in current refractory linings is chrome oxide. NETL is researching new types of refractory materials as an alternative to the high chrome oxide refractories currently used, with the goal of improving performance and providing a predictable service life. It has previously developed and patented the use of phosphate additives to improve the wear and spalling resistance of high chrome oxide refractories, and is exploring chrome and non-chrome oxide materials through laboratory testing and the use of thermodynamic modeling. In this paper, the results of a different additive (carbon) was evaluated by laboratory testing and found to improve slag penetration resistance. Data on this evaluation will be presented, and is proposed as a means of improving the molten slag wear resistance of the refractory. The use of it as a means of improving refractory service life in the field is patent pending.
Authors: Zheng Zhai, Qing Liu, Xing You Xu, Ju Yuan Li, Zheng Li, Xiang Chen Li
Abstract: A new type of isotope preparation system was designed with excellent accuracy, high degree automation and high security. In view of the existing equipment with automation low degree automation, poor safety, much long preparation time and low precision of the sample preparation problems, a series of improvements were introduced, such as the automatic sampling device, contact valve, vacuum auxiliary system, gas meter and digital dashboards. It was found that the instrument finely designed had the characteristics such as high accuracy, automation and security. Combined with the sample detection device, the preparated sample had excellent detection results. Meanwhile, a set of standard operating procedures had also been formed. Furthermore, the sample preparation process was briefly discussed.
Authors: Wen Xia Xie, Kun Jie Zhu, Hui Na Du
Abstract: As a supplementary theory of ecological system research, ecological stoichiometry has been applied to many research fields of wetland ecosystems at home and abroad. This article reported carbon nitrogen phosphorus element stoichiometry of soil, vegetation, among different components and after artificial disturbance in wetland ecosystems. Research showed that wetland ecological stoichiometry characteristics have important influences on the change and their interaction of carbon nitrogen phosphorus in the whole system and the internal mechanism of the carbon nitrogen phosphorus balance of wetland ecosystems. At the same time, it has provided an important reference for the management and protection of wetland ecological system.
Authors: M.S. Shamsudin, S.M. Sanip
Abstract: The unsurpassed and exceptional properties of graphene (Gr) have prompted significant progress toward Gr-based applications, and have furthermore unleashed a host of complimentary two-dimensional materials that provide new, and emerging technologies synergistic with an already well-established Gr science. The Raman spectroscopy reveals both basic and advance features. It emerged as an important optical and structural characterization tool, following in the footsteps of related form of carbon. Till date, no comprehensive descriptions of Raman spectroscopy on Gr characterization have been published yet. This is to say that, no review can possibly complete. We have presented an extensive overview of the Raman spectroscopy, filled-up this gap and discussed the theoretical background associated with the Gr and other carbon-based materials, and some thoughts about the future of this field are highlighted. Thus, it would be used as a reference guide for the utilization of Raman spectroscopy to investigate the various features of Gr and carbon-based materials.
Authors: Seiichi Muneki, Hiroshi Okubo, Fujio Abe
Abstract: In order to improve the creep strength of the heat resistant steels at elevated temperatures over 700°C, a new attempt has been demonstrated using carbon and nitrogen free Fe-Ni martensitic and austenitic alloys strengthened by Laves phase such as Fe2W and Fe2Mo. It is important that these alloys are independent of any carbides and any carbo-nitrides as strengthening factors. The high temperature creep tests over 700°C exceed 36,000 hours and the test is continued. Creep behavior of alloys is found to be completely different from that of the conventional high-Cr ferritic steels. The alloys exhibit gradual change in the creep rate with strain both in the transient and acceleration creep regions, and give a larger strain for the minimum creep rate. Effect of Cr on the Fe-12Ni-9Co-10W alloys on the creep properties more over 700°C was investigated. It became clear that the value for 100,000 hours was exceeded at 700°C and 100MPa calculated from the Larson-Miller parameter at C=20. And surface appearance of crept specimen was investigated in detail.
Authors: Rajarshi Chakraborty, Suresh C. Sharma, J. Kyle Laroque
Abstract: Diamond nanoparticles (NPs), grown by chemical vapor deposition (CVD), have been characterized by utilizing AFM, SEM, and Raman spectroscopy. AFM and SEM data show increase in NPs size with growth period, ranging from about 20 nm for 15 min to 200 nm for 105 min growth. The Raman spectra show a sharp line at around 1332 cm-1, which is characteristic of diamond structure. We analyze the Raman spectra by using optical phonon confinement in nm-size crystals and discuss the resulting data for NP sizes.
Authors: Li Hua Cheng, Xue Jun Bi, Chang Qing Liu
Abstract: Due to increasing water scarcity, appropriate technologies were need for advanced treatment of wastewater to enable reuse. Effect of iron-carbon internal electrolysis in tertiary treatment of wastewater was investigated in this study. Static experiment was adopted to evaluate influence of Fe/C ratio, pH, reaction time and aeration on pollutant removal by iron-carbon internal electrolysis. Then dynamic experiment was conducted to determine removal rate of CODcr, TP, chroma and NO3--N. The results showed that internal electrolysis could remove CODcr, TP and chroma efficiently. The optimal ratio of Fe/C was 1:1. Initial pH could affect removal efficiency. In acid circumstance, the removal rate was higher. Degradation reaction by internal electrolysis was fast. when the reaction time was 10min, the removal rate could be ideal. In the process of internal electrolysis, aeration could increase pollutant removal rate. In aerated system, when the reaction time was only 15min, removal rate of CODcr, TP and chroma could reach 49.2%, 89% and 75%. But in non-aerated system, only when the reaction time was 100min could removal rate of these indexes reach 46.5%, 81% and 85.1%. In dynamic experiment, removal rate of CODcr, TP, chroma and NO3- could reach above 40%, 90%, 75% and 20%, respectively.
Authors: Xin Hua Wu, Joaquin Del Prado, D. Hu, A. Huang, M.Q. Chu, M.H. Loretto
Abstract: Samples of Ti-15Cr and Ti-15V-3Sn-3Al-3Cr (wt%) containing controlled additions of carbon up to 0.2wt% and different oxygen contents have been quenched and aged at temperatures between 400 and 600°C. Optical, scanning and analytical transmission electron microscopy have been used to characterise the microstructures of the quenched and aged samples. Hardness testing has been used to follow the kinetics and extent of age hardening, which are accelerated in Ccontaining samples. The addition of carbon results in the formation of Ti(CxOy) precipitates which pin grain boundaries in forged samples so that the grain size in the quenched C-containing samples is about a factor of ten less than that in the C-free samples. In the C-free samples coarse grain boundary alpha tends to form, but in the C-containing samples alpha precipitation is more uniform throughout the beta grains. The extent of omega precipitation is very different in the two alloys; the Ti-15Cr alloy forms athermal omega in the as-quenched samples and large omega precipitates are formed on ageing at 400°C. No evidence for omega has been obtained in the Ti-15-3. The hardening responses and microstructural observations are interpreted in terms of the different grain boundary oxygen contents in the C-containing and C-free samples and the different roles of omega and of carbon in the two alloys.
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