| 1. |
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| 2. |
- Chen, Shujing, et al.
(författare)
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Manufacturing Graphene-Encapsulated Copper Particles by Chemical Vapor Deposition in a Cold Wall Reactor
- 2019
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Ingår i: ChemistryOpen. - : Wiley. - 2191-1363. ; 8:1, s. 58-63
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Tidskriftsartikel (refereegranskat)abstract
- Functional fillers, such as Ag, are commonly employed for effectively improving the thermal or electrical conductivity in polymer composites. However, a disadvantage of such a strategy is that the cost and performance cannot be balanced simultaneously. Therefore, the drive to find a material with both a cost efficient fabrication process and excellent performance attracts intense research interest. In this work, inspired by the core-shell structure, we developed a facile manufacturing method to prepare graphene-encapsulated Cu nanoparticles (GCPs) through utilizing an improved chemical vapor deposition (CVD) system with a cold wall reactor. The obtained GCPs could retain their spherical shape and exhibited an outstanding thermal stability up to 179 degrees C. Owing to the superior thermal conductivity of graphene and excellent oxidation resistance of GCPs, the produced GCPs are practically used in a thermally conductive adhesive (TCA), which commonly consists of Ag as the functional filler. Measurement shows a substantial 74.6 % improvement by partial replacement of Ag with GCPs.
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| 3. |
- Dai, Zhengxing, et al.
(författare)
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Prediction and verification of heat capacities for pure ionic liquids
- 2021
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Ingår i: Chinese Journal of Chemical Engineering. - : Elsevier. - 1004-9541 .- 2210-321X. ; 31, s. 169-176
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Tidskriftsartikel (refereegranskat)abstract
- The heat capacity of ionic liquids is an important physical property, and experimental measuring is usually used as a common method to obtain them. Owing to the huge number of ionic liquids that can be potentially synthesized, it is desirable to acquire theoretical predictions. In this work, the Conductor-like Screening Model for Real Solvents (COSMO-RS) was used to predict the heat capacity of pure ionic liquids, and an intensive literature survey was conducted for providing a database to verify the prediction of COSMO-RS. The survey shows that the heat capacity is available for 117 ionic liquids at temperatures ranging 77.66-520 K since 2004, and the 4025 data points in total with the values from 76.37 to 1484 J·mol-1·K-1 have been reported. The prediction of heat capacity with COSMO-RS can only be conducted at two temperatures (298 and 323 K). The comparison with the experimental data proves the prediction reliability of COSMO-RS, and the average relative deviation (ARD) is 8.54%. Based on the predictions at two temperatures, a linear equation was obtained for each ionic liquid, and the heat capacities at other temperatures were then estimated via interpolation and extrapolation. The acquired heat capacities at other temperatures were then compared with the experimental data, and the ARD is only 9.50%. This evidences that the heat capacity of a pure ionic liquid follows a linear equation within the temperature range of study, and COSMO-RS can be used to predict the heat capacity of ionic liquids reliably.
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| 4. |
- Zhang, Maomao, et al.
(författare)
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Effect of pressure during graphitization on mechanical properties of graphene films
- 2019
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Ingår i: 2019 20th International Conference on Electronic Packaging Technology, ICEPT 2019.
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Konferensbidrag (refereegranskat)abstract
- Graphene films (GFs) can be used in the field of electronics cooling, owing to many outstanding properties. In the present paper, GFs samples were graphitized at different pressures to study their effect on the mechanical properties. The elastic modulus and hardness of GFs were measured by nanoindentation and the tensile strength of GFs were obtained by stretching GFs in a tensile tester. Meanwhile, GFs were characterized by X-ray diffraction(XRD), Scanning electron microscopy (SEM) and Raman spectroscopy. The results show that the modulus, hardness and tensile strength of GFs were strongly influenced by the defect and wrinkles among other things.
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| 5. |
- Chen, Jun, et al.
(författare)
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Collaborative validation of GlobeLand30 : Methodology and practices
- 2021
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Ingår i: Geo-spatial Information Science. - : TAYLOR & FRANCIS LTD. - 1009-5020 .- 1993-5153. ; 24:1, s. 134-144
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Tidskriftsartikel (refereegranskat)abstract
- 30-m Global Land Cover (GLC) data products permit the detection of land cover changes at the scale of most human land activities, and are therefore used as fundamental information for sustainable development, environmental change studies, and many other societal benefit areas. In the past few years, increasing efforts have been devoted to the accuracy assessment of GlobeLand30 and other finer-resolution GLC data products. However, most of them were conducted either within a limited percentage of map sheets selected from a global scale or in some individual countries (areas), and there are still many areas where the uncertainty of 30-m resolution GLC data products remains to be validated and documented. In order to promote a comprehensive and collaborative validation of 30-m GLC data products, the GEO Global Land Cover Community Activity had organized a project from 2015 to 2017, to examine and explore its major problems, including the lack of international agreed validation guidelines and on-line tools for facilitating collaborative validation activities. With the joint effort of experts and users from 30 GEO member countries or participating organizations, a technical specification for 30-m GLC validation was developed based on the findings and experiences. An on-line validation tool, GLCVal, was developed by integrating land cover validation procedures with the service computing technologies. About 20 countries (regions) have completed the accuracy assessment of GlobeLand30 for their territories with the guidance of the technical specification and the support of GLCVal.
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| 6. |
- Chen, Jingjing, et al.
(författare)
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Designing heat exchanger for enhancing heat transfer of slurries in biogas plants
- 2019
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Ingår i: Innovative Solutions for Energy Transitions. - : Elsevier. ; , s. 1288-1293
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Konferensbidrag (refereegranskat)abstract
- Heat transfer geometries with enhanced performance for the slurries with high viscosity can improve the net raw biogas production in bio-methane process. In this study, the rheological properties of different slurries were tested, correlated and implemented to computational fluid dynamics (CFD). CFD was then used to screen a new geometry based on the twisted tube combined with mechanism study, and experimental testing was conducted for verification. It shows that the twisted hexagonal tube (THT) has the highest performance. The mechanism for enhancing the heat transfer with THT was mainly due to the effective shear rate. Furthermore, the waste-heat recovery with the THT heat exchanger in biogas production was estimated quantitatively and compared with the normal heat exchanger and scraped-surface heat exchanger (SSHE). Compared to the normal heat exchanger, for THT, the increase of net raw biogas production δNRBP can be up to 17%, while it is only up to 8.53% for SSHE. Besides, the external heating up processes with THT and normal heat exchanger were studied to estimate the heating time for different temperature fluctuations and power requirements of boiler. It is found that the process with THT can save 25-38% heating time for the anaerobic reactor compared to the normal heat exchanger. Therefore, designed THT heat exchanger is promising, and the developed methods can also be beneficial for studying other heat transfer processes.
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| 7. |
- Chen, Yifeng, et al.
(författare)
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Thermodynamic Study for Gas Absorption in Choline-2-pyrrolidine-carboxylic Acid + Polyethylene Glycol
- 2016
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Ingår i: Journal of Chemical and Engineering Data. - : American Chemical Society (ACS). - 0021-9568 .- 1520-5134. ; 61:10, s. 3428-3437
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Tidskriftsartikel (refereegranskat)abstract
- The solubility of pure CO2, CH4, and N2 in the mixture of choline-2-pyrrolidine carboxylic acid ([Cho][Pro]) and polyethylene glycol (PEG200) (mass ratio = 1:2) was measured experimentally at temperatures from 308.15 to 338.15 K and pressures up to 28 bar, in which [Cho][Pro] is an ionic liquid and PEG200 is a cosolvent with the purpose to decrease the viscosity. It was found that [Cho][Pro]/PEG200 showed a good selectivity for CO2/CH4 and CO2/N2 separation. The measured experimental data points from this work and others were further used to estimate the thermodynamic properties including the Henry's law constants for the gases in [Cho][Pro]/PEG200, the equilibrium constant for the reaction between CO2 and [Cho][Pro], the CO2 absorption enthalpy in [Cho][Pro]/PEG200, and so forth. The consistent results of the CO2 absorption enthalpy at infinite dilution prove the reliability of the thermodynamic properties obtained in this work. The thermodynamic properties of [Cho][Pro]/PEG200 were further compared with other three typical absorbents, and the absorption enthalpy is nearly half of that for 30 wt % MEA aqueous solution. At the same time, the theoretical amount of absorbents needed for [Cho][Pro]/PEG200 is much lower than that of H2O scrubbing. This shows that [Cho][Pro]/PEG200 is a promising absorbent
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| 8. |
- Fan, Tengteng, et al.
(författare)
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CO2/N2 separation using supported ionic liquid membranes with green and cost-effective [Choline][Pro]/PEG200 mixtures
- 2016
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Ingår i: Chinese Journal of Chemical Engineering. - : Elsevier BV. - 1004-9541 .- 2210-321X. ; 24:11, s. 1513-1521
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Tidskriftsartikel (refereegranskat)abstract
- The high price and toxicity of ionic liquids (ILs) have limited the design and application of supported ionic liquid membranes (SILMs) for CO2 separation in both academic and industrial fields. In this work, [Choline][Pro]/polyethylene glycol 200 (PEG200) mixtures were selected to prepare novel SILMs because of their green and cost-effective characterization, and the CO2/N2 separation with the prepared SILMs was investigated experimentally at temperatures from 308.15 to 343.15 K. The temperature effect on the permeability, solubility and diffusivity of CO2 was modeled with the Arrhenius equation. A competitive performance of the prepared SILMs was observed with high CO2 permeability ranged in 343.3-1798.6 barrer and high CO2/N2 selectivity from 7.9 to 34.8. It was also found that the CO2 permeability increased 3 times by decreasing the viscosity of liquids from 370 to 38 mPa·s. In addition, the inherent mechanism behind the significant permeability enhancement was revealed based on the diffusion-reaction theory, i.e. with the addition of PEG200, the overall resistance was substantially decreased and the SILMs process was switched from diffusion-control to reaction-control.
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| 9. |
- He, Hanbing, et al.
(författare)
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Kinetics for Preparation of K2Ti2O5 Using TiO2 Microparticles and Nanoparticles as Precursors
- 2014
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Ingår i: Chinese Journal of Chemical Engineering. - : Elsevier BV. - 1004-9541 .- 2210-321X. ; 22:10, s. 1105-1110
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Tidskriftsartikel (refereegranskat)abstract
- The formation mechanism of K2Ti2O5 was investigated with TiO2 microparticles and nanoparticles as precursors by thermogravimetric (TG) technique. A method of direct multivariate non-linear regression was applied for simultaneous calculation of solid-state reaction kinetic parameters from TG curves. TG results show more regular decrease from initial reaction temperature with TiO2 nanoparticles as raw material compared with TiO2 microparticles, while mass losses finish at similar temperatures under the experimental conditions. From the mechanism and kinetic parameters, the reactions with the two materials are complex consecutive processes, and reaction rate constants increase with temperature and decrease with conversion. The reaction proceedings could be significantly hindered when the diffusion process of reactant species becomes rate-limiting in the later stage of reaction process. The reaction active sites on initial TiO2 particles and formation of product layers may be responsible to the changes of reaction rate constant. The calculated results are in good agreement with experimental ones.
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| 10. |
- He, Ming, et al.
(författare)
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A controllable approach for the synthesis of titanate derivatives of potassium tetratitanate fiber
- 2004
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Ingår i: Journal of Materials Science. - 0022-2461 .- 1573-4803. ; 39, s. 3745-3750
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Tidskriftsartikel (refereegranskat)abstract
- Three types titanate derivatives, K2Ti6O13 fiber, K2Ti8O17 fiber and anatase TiO2 fiber, were synthesized by ion-exchange reaction from potassium tetratitanate fiber (K2Ti4O9) based on the hydrate conditions predicted by a thermodynamic model. These products were formed by a heat treatment of the corresponding hydrate intermediates K1.33H0.67Ti4O9·H2O, KHTi4O9·0.5H2O and H2Ti4O9·1.2H2O which were quantitatively obtained by controlling the pH value and the equilibrium concentration of potassium ion. The mole ratio of Ti/K in solid phase (R) of the target products was taken as the controlling aim in the hydrate process. The temperature for heat treatment of hydrate intermediates was determined by thermogravimetry (TG) and differential scanning calorimetry (DSC). All products retained fibrous morphology similar to that of K2Ti4O9 used as the starting material.
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| 11. |
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| 12. |
- Ji, Yuanhui, et al.
(författare)
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Modeling of specific structure crystallization coupling with dissolution
- 2010
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Ingår i: Frontiers of Chemical Science and Engineering. - : Springer Science and Business Media LLC. - 1673-7369. ; 4:1, s. 52-56
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, the research framework for specific structure crystallization modeling has been proposed in which four steps are required in order to investigate the rigorous crystallization modeling by thermodynamics. The first is the activity coefficient model of the solution, the second is Solid-Liquid equilibrium, the third and fourth are the dissolution and crystallization kinetics modeling, respectively. Our investigations show that the mechanisms of complex structure formation and microphase transition can be analyzed by combining the dissolution and crystallization kinetics modeling. Moreover, the formation mechanism of the porous KCl has been analyzed, which may provide a reference for the porous structure formation in the advanced material synthesis
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| 13. |
- Ji, Yuanhui, et al.
(författare)
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Modelling of mass transfer coupling with crystallization kinetics in microscale
- 2010
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Ingår i: Chemical Engineering Science. - : Elsevier BV. - 0009-2509 .- 1873-4405. ; 65:9, s. 2649-2655
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Tidskriftsartikel (refereegranskat)abstract
- Microstructure technologies have attracted interests in chemistry, chemical engineering, and biotechnology. To investigate the mass transfer of ions and crystallization of crystals in microscale and then to explain the formation mechanism of the porous structure materials, a microscale mathematical model for mass transfer processes coupling with local reactions is proposed in which the chemical potential gradient Δμ is used as the driving force to avoid the discontinuity of the kinetics equations in the micro-channels. Meanwhile, the dissolution kinetics of KCl at 298.15 K is measured to determine the dissolution rate constant kd and the average area of crystals Ac. The investigation for the fractional crystallization process of carnallite shows that the calculated mixing time versus channel width agree with the Einstein diffusion equation, which validates that the model can be used to describe the ion diffusion very well. Meanwhile, to have an accurate Δμ of KCl, in the channel width of or narrower than 2.0×10-6 m, it is enough to consider the diffusion only, while in the channel width of or wider than 2.0×10-5 m, diffusion should be coupled with reaction. The investigation also shows the vital of the consideration of the ionic activity coefficient for the investigated systems in micron scales. Moreover, the new formation mechanism of the porous structures in the inorganic material fabrication will be proposed from the process simulation for the synthesis of porous KCl, which will provide a reference for the porous structure formation in the advanced inorganic material synthesis.
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| 14. |
- Ji, Yuanhui, et al.
(författare)
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Progress in the study on the phase equilibria of the CO2-H2O and CO2-H2O-NaCl systems
- 2007
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Ingår i: Chinese Journal of Chemical Engineering. - 1004-9541 .- 2210-321X. ; 15:3, s. 439-448
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Tidskriftsartikel (refereegranskat)abstract
- To study the feasibility of CO2 geological sequestration, it is needed to understand the complicated multiple-phase equilibrium and the densities of aqueous solution with CO2 and multi-ions under wide geological conditions (273.15-473.15 K, 0-60 MPa), which are also essential for designing separation equipments in chemical or oil-related industries. For this purpose, studies on the relevant phase equilibria and densities are reviewed and analyzed and the method to improve or modify the existing model is suggested in order to obtain more reliable predictions in a wide temperature and pressure range. Besides, three different models (the electrolyte non random two-liquid (ELECNRTL), the electrolyte NRTL combining with Helgeson model (ENRTL-HG), Pitzer activity coefficient model combining with Helgeson model (PITZ-HG)) are used to calculate the vapor-liquid phase equilibrium of CO2-H2O and CO2-H2O-NaCl systems. For CO2-H2O system, the calculation results agree with the experimental data very well at low and medium pressure (0-20 MPa), but there are great discrepancies above 20 MPa. For the water content at 473.15 K, the calculated results agree with the experimental data quite well. For the CO2-H2O-NaCl system, the PITZ-HG model show better results than ELECNRTL and ENRTL-HG models at the NaCl concentration of 0.52 mol•L-1. Bur for the NaCl concentration of 3.997 mol•L-1, using the ELECNRTL and ENRTL-HG models gives better results than using the PITZ-HG model. It is shown that available experimental data and the thermodynamic calculations can satisfy the needs of the calculation of the sequestration capacity in the temperature and pressure range for disposal of CO2 in deep saline aquifers. More experimental data and more accurate thermodynamic calculations are needed in high temperature and pressure ranges (above 398.15 K and 31.5 MPa).
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| 15. |
- Ji, Yuanhui, et al.
(författare)
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Thermodynamic analysis on the mineralization of trace organic contaminants with oxidants in advanced oxidation processes
- 2009
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Ingår i: Industrial & Engineering Chemistry Research. - : American Chemical Society (ACS). - 0888-5885 .- 1520-5045. ; 48:23, s. 10728-10733
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Tidskriftsartikel (refereegranskat)abstract
- There is a growing demand for the efficient treatment of organic polluted wastewaters by advanced oxidation processes (AOPs) which calls for the determination of the mineralization order of ease for the organic contaminants with oxidants. The mineralization abilities of organic contaminants in AOPs are investigated in this work. Photocatalytic experiments for three representative organic contaminants are carried out, and their corresponding reaction rates are determined experimentally. Meanwhile, molar Gibbs free energy changes Delta(r)G(m)degrees for the reactions of 31 organic contaminants (10 chlorinated hydrocarbons, four brominated hydrocarbons, I I aromatic hydrocarbons and their derivatives, three chloroacetic acid, and three chloroacetyl chloride) with oxidants of (OH)-O-center dot, H2O2, O-center dot(-), O-3, and O-2 are calculated, and the mineralization order of ease is determined theoretically on the basis of Delta(r)G(m)degrees. The agreement of the theoretical and experimental mineralization abilities for most of the organic contaminants investigated implies the reliability of the determination of the mineralization ability from the magnitude of Delta(r)G(m)degrees for the mineralization of trace organic contaminants. Results also show that for most of the organic contaminants studied, the mineralization abilities are (OH)-O-center dot > H2O2 > O-center dot(-) > O-3 > O-2, and the mineralization ability of the organic contaminants depends on not only the oxidants but also the structure and properties of the organic contaminants themselves, and the degradation reaction products.
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| 16. |
- Ji, Yuanhui, et al.
(författare)
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Thermodynamic study on the reactivity of trace organic contaminant with the hydroxyl radicals in waters by advanced oxidation processes
- 2009
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Ingår i: Fluid Phase Equilibria. - : Elsevier BV. - 0378-3812 .- 1879-0224. ; 277:1, s. 15-19
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Tidskriftsartikel (refereegranskat)abstract
- This paper is to investigate the degradation abilities of various chlorinated aliphatics, benzene and its derivatives in order to treat organic polluted wastewaters efficiently by advanced oxidation processes (AOPs). A thermodynamic method is proposed to calculate the standard molar Gibbs energy of formation for aqueous organic species. Using the method proposed, the standard molar Gibbs energies of formation for 31 aqueous organic species are obtained. Moreover, the molar Gibbs energy change of reaction Δr Gm0 for the organic species with hydroxyl radicals is calculated from the standard molar Gibbs energy of formation for aqueous organic species to determine the degradation order of ease for the organic species. New photocatalytic experiments are carried out for the model verification. The calculation results of the model agree with the available and new experimental results. This work shows that the thermodynamics of the degradation reaction for the organic pollutants in AOPs can find the corresponding relationships with the degradation reaction rate by experimental measurements. The work in this paper represents a success of thermodynamics for the application in environmental area.
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| 17. |
- Li, Xun, et al.
(författare)
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Investigation of burning velocity of lean and rich premixed NH3/H2 turbulent flames using multi-scalar imaging
- 2024
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Ingår i: Proceedings of the Combustion Institute. - 1540-7489. ; 40:1-4
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Tidskriftsartikel (refereegranskat)abstract
- Two groups of both lean and rich NH3/H2/O2/N2 turbulent premixed piloted jet flames with the same laminar flame speed are investigated using simultaneous multi-scalar laser diagnostics techniques including NH3/NH/OH planar laser induced fluorescence (PLIF) and Rayleigh scattering. One group uses air as the oxidizer and the other uses an adapted mixture of atomic N-to-H ratio of 1:3 associated with in-situ hydrogen production from ammonia cracking. Turbulent rms velocity uʹ is varied in a wide range by changing the bulk flow velocity. Global consumption speeds ST,G are evaluated by measuring the inlet bulk flow rates of reactants and areas of time-averaged flame fronts extracted using different flame marker contours, i.e., cNH3 = 0.3, cNH = 0.3 (inner contour), and cOH = 0.4, where c designates species number density normalized using its maximum value. The obtained results show the following trends to be emphasized. First, an increase in ST,G,NH3 by uʹ is more pronounced when compared to two other global consumption speeds (ST,G,NHi , where i indicates the inner contour, and ST,G,OH ) and is close to a linear dependence. The adapted mixture shows only a moderate influence on ST,G,NH3 but not on the other two. Second, ST,G,NH3 is weakly affected by variations in Lewis number Le. On the contrary, third, ST,G,NHi is significantly higher in lean mixtures characterized by Le < 1 when compared to rich mixtures characterized by Le > 1. Fourth, these variations in ST,G,NHi are reasonably well approximated introducing an empirical factor of Le−0.9 into fitting ST,G,NHi /SL onto uʹ/SL . The qualitative difference between sensitivities of ST,G,NH3 and ST,G,NHi to variations in Le is attributed to the fact that the NH3 and NH isosurfaces are localized to preheat and reaction zones, respectively, of the laminar flames. The reported experimental data imply different influence of differential diffusion on flame preheat and reaction zones, thus, calling for further research into the issue.
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| 18. |
- Li, Ze, et al.
(författare)
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Modulated-Virtual-Vector-Based Predictive Current Control for Dual Three-Phase PMSM With Enhanced Steady-State Performance
- 2023
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Ingår i: IECON 2023 - 49th Annual Conference of the IEEE Industrial Electronics Society. - : Institute of Electrical and Electronics Engineers (IEEE).
-
Konferensbidrag (refereegranskat)abstract
- Dual three-phase permanent magnet synchronous machine (DTP-PMSM) has attracted great attention due to its high reliability and high-power output capacities. However, the conventional single-voltage-vector-based predictive current control (SV-PCC) for DTP-PMSM presents high torque ripple and current harmonics, and high computational burden. To solve those issues, a modulated-virtual-vector-based PCC (MVV-PCC) for DTP-PMSM is proposed in this paper. Wherein, twenty-four VVs are synthesized by the inherent voltage vectors, and two VVs and one zero voltage vector with optimal duty cycles are determined and applied in each sampling period to improve the steady-state performance. The selection of optimal VVs and the calculation of the optimal duty cycles are simplified by integrating the deadbeat control and modulation scheme. Various comparisons are carried out to validate the effectiveness and superiority of the proposed MVV-PCC strategy.
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| 19. |
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| 20. |
- Liu, Chang, et al.
(författare)
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Determination of the ion exchange process of K2Ti4O9 fibers at constant pH and modeling with statistical rate theory
- 2015
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Ingår i: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 5:90, s. 73474-73480
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Tidskriftsartikel (refereegranskat)abstract
- The ion exchange kinetics of K2Ti4O9 fibers at constant pH was determined precisely by ion-selective electrodes, and activity coefficients of ions in solutions were calculated by the Lu-Maurer equation. It was found that the equilibrium time and TiO2/K2O molar ratio in the solid phase are more sensitive to pH than to water volume. After that, a two-step exchange kinetics model was developed, in which a statistical rate theory base on chemical potential difference between interface was use to describe surface reaction process instead of an empirical exponential equation. The model shows that the resistance of the surface reaction step, which includes hydration of K+ ions on the surface and their transport in the solid phase, is the main resistance of the ion exchange process.
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| 21. |
- Liu, Chang, et al.
(författare)
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The biomethane producing potential in China : A theoretical and practical estimation
- 2016
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Ingår i: Chinese Journal of Chemical Engineering. - : Elsevier BV. - 1004-9541 .- 2210-321X. ; 24:7, s. 920-928
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Tidskriftsartikel (refereegranskat)abstract
- Biomethane has been developed rapidly in many countries as a renewable energy which upgraded from biogas. China also began to pay attention to it even though we still at a initial stage, primarily, understanding the biomethane potential and development prospect, choosing appropriate biomass as the biomethane source is very important. In this work, the theoretical and practical biomethane producing potential from five main biomass resources in China were estimated with appropriate methods based on the data collected, and during calculation, two appropriate energy crops were assumed to be planted on marginal lands for biomethane production. Our estimation showed that the theoretical and practical biomethane potentials in China can reach to 888.78 and 316.30 billion m3 per year, agricultural waste should be the preferential development biomass, and planting energy crops on marginal lands is the most promising way to enhance biomethane production in China. When compared with natural gas, Chinese natural gas consumption in 2013 only account for 48.15 % of the practical biomethane potential.
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| 22. |
- Liu, Sida, et al.
(författare)
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Improved CO2 separation performance of aqueous choline-glycine solution by partially replacing water with polyethylene glycol
- 2019
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Ingår i: Fluid Phase Equilibria. - : Elsevier. - 0378-3812 .- 1879-0224. ; 495, s. 12-20
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Tidskriftsartikel (refereegranskat)abstract
- Aqueous choline-glycine ([Cho][Gly]) solution is a potential candidate for CO2separation owing to its excellent absorption performance and biodegradability. Moreover, the aqueous solution is easy to volatilize at high temperatures. In this work, H2O was partially replaced with polyethylene glycol (PEG200) and the effect of PEG200 on the CO2 separation performance in [Cho][Gly])/H2O was investigated. The viscosity of [Cho][Gly]/H2O/PEG200 and CO2 solubility in the solution were determined experimentally in the temperature range 308.15–338.15 K at pressures ≤6.5 bar. Further, the measured CO2 solubility was fitted with the reaction equilibrium thermodynamic model and the CO2 desorption enthalpy was estimated. The regeneration performance of [Cho][Gly]/H2O/PEG200 was also evaluated. The results revealed that [Cho][Gly]/H2O/PEG200 has a low CO2desorption enthalpy and high regeneration efficiency. Particularly, [Cho][Gly]/H2O/PEG200 with 30 wt% PEG200 has a high regeneration efficiency of 95%. Owing to its physical-chemical properties and CO2 separation performance, [Cho][Gly]/H2O/PEG200 shows great potential as an absorbent for CO2 separation.
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| 23. |
- Liu, Xiangdong, et al.
(författare)
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Cancer risk in patients with hepatitis C virus infection : A population-based study in Sweden
- 2017
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Ingår i: Cancer Medicine. - : Wiley. - 2045-7634. ; 6:5, s. 1135-1140
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Tidskriftsartikel (refereegranskat)abstract
- Increased risks of certain cancers have been observed in patients with hepatitis C virus (HCV) infection. However, data on other cancer sites/types are lacking. We analyzed systematically the risk of developing 35 common cancers in patients with HCV infection using a nationwide Swedish database. Patients with HCV infection were identified from the Swedish Hospital Inpatient and Outpatient Register and Primary Health Care Database, and followed until the diagnosis of cancer. Standardized incidence ratios (SIRs) were calculated for subsequent 35 common cancer sites/types between 1990 and 2010 in patients with HCV infection in Sweden. Increased risks were recorded for six cancers. The highest SIR was seen for liver cancer (36.67; 95% CI: 33.20-40.40). The decreased risk was for prostate cancer (0.73; 95% CI: 0.59-0.90) and melanoma (0.50; 95% CI: 0.30-0.79). A significant sex-difference for cancer was observed only for liver cancer (40.72; 95% CI: 36.36-45.45 for men and 27.21; 95% CI: 21.90-33.41 for women). Also, increased SIRs were noted only for liver cancer during the entire period of follow-up. HCV infection was associated with an increased incidence of liver cancer and additionally five other types of cancer. Active surveillance of other cancers may be needed in order to be diagnosed at an earlier stage.
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| 24. |
- Liu, Yaoqian, et al.
(författare)
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Adjusting the rheological properties of corn-straw slurry to reduce the agitation power consumption in anaerobic digestion
- 2018
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Ingår i: Bioresource Technology. - : Elsevier. - 0960-8524 .- 1873-2976. ; 272, s. 360-369
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Tidskriftsartikel (refereegranskat)abstract
- Agitation power consumption (P) in the anaerobic digestion of biogas plants is a major consumer of electric energy. To reduce P by adjusting the rheological properties, in this work, the rheological properties of the corn-straw slurry were studied systematically considering the effects of TS, temperature and particle-size, and P was calculated based on the rheological behavior of the corn-straw slurry. The investigation shows that the corn-straw slurry is a non-Newtonian fluid and exhibit shear-thinning behavior, and the rheological properties can be well described with the power law model. The size-reduction is more effective compared to the option of temperature-increase to improve the agitation power efficiency, and the value of P can be reduced by up to 48.11 %. Since the size-reduction can also increase the methane yield, the reduction of the particle-size is a promising option to save P, especially at relatively high TSs and for the thermophilic AD process.
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| 25. |
- Liu, Yaoqian, et al.
(författare)
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Reducing the agitation power consumption in anaerobic digestion of corn straw by adjusting the rheological properties
- 2019
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Ingår i: Energy Procedia. - : Elsevier. - 1876-6102. ; 158, s. 1267-1272
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Tidskriftsartikel (refereegranskat)abstract
- Agitation power consumption (P) in the anaerobic digestion of biogas plants is a major part of the electric energy consumption. To reduce P by adjusting the rheological properties, in this work, the rheological properties of corn straw slurry were studied systematically with the consideration of the effects of TS, temperature and particle sizes. The P was calculated based on the rheological behaviour of corn straw slurry. The investigation shows that the thermophilic digestion is effective only for the slurry with a relatively high TS. The size-reduction is more effective at higher TS compared to the option of increasing temperature in order to improve the agitation power efficiency, and the value of P can be reduced by up to 48.11 %. Since the size-reduction can also increase the methane yield, the adjustment of particle sizes is a promising option to save P, especially at higher TS.
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| 26. |
- Ma, Chunyan, et al.
(författare)
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Evaluation and comparison of aqueous ChCl/Urea and other physical absorbents for biogas upgrading process
- 2017
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Ingår i: Energy Procedia. - : Elsevier. - 1876-6102. ; 142, s. 3631-3636
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Tidskriftsartikel (refereegranskat)abstract
- Biogas has been considered as an alternative renewable energy, and CO2 removal from raw biogas (i.e. biogas upgrading) is needed for producing biomethane used as vehicle fuels or injected into the natural gas grid. Biogas upgrading using physical absorbents is a simple and efficient technology with low energy requirements for regeneration. In this work, the conceptual process for biogas upgrading using 4 kinds of physical solvents, i.e. water, dimethyl ether of polyethylene glycol (DEPG), propylene carbonate (PC) and aqueous choline chloride (ChCl) /urea (AQDES) was developed and simulated with Aspen Plus. The energy utilization, the amount of recirculated solvent and the diameters of absorber and desorber were analyzed based on equilibrium approach. After that, the rate-based simulation was established to evaluate the specific cost of the process using different solvents. Based on equilibrium approach the comparison between the solvents in respect to the energy utilization for biogas upgrading using different solvents shows the following order: DEPG > water > AQDES > PC, whereas the amount of recirculated solvent and the diameters of absorber and desorber follow another order: water > DEPG > AQDES > PC. The rate-based results show that the process using PC has the lowest total specific cost, followed by AQDES, water and DEPG.
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| 27. |
- Ma, Chunyan, et al.
(författare)
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Modeling, simulation and evaluation of biogas upgrading using aqueous choline chloride/urea
- 2017
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Ingår i: Applied Energy. - : Elsevier. - 0306-2619 .- 1872-9118. ; 229:1, s. 1269-1283
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Tidskriftsartikel (refereegranskat)abstract
- Biogas has been considered as an alternative renewable energy, and raw biogas needs to be upgraded in order to be used as vehicle fuels or injected into the natural gas grid. In this work, the conceptual process for biogas upgrading using aqueous choline chloride (ChCl)/urea (1:2 on a molar basis) was developed, simulated and evaluated based on the commercialized software Aspen Plus. Reliable thermophysical properties and phase equilibria are prerequisite for carrying out process simulation. In order to carry out the process simulation, the thermophysical properties of ChCl/Urea (1:2) and its aqueous solutions as well as the phase equilibria of gas-ChCl/Urea (1:2), ChCl/Urea (1:2)-H2O and gas-ChCl/Urea (1:2)-H2O were surveyed and evaluated. After evaluation, the consistent experimental data of these thermophysical properties were fitted to the models embedded in Aspen Plus. The properties needed but without available experimental results were predicted theoretically. The Non-Random Two-Liquid model and the Redlich-Kwong equation (NRTL-RK) model were used to describe the phase equilibria. The equilibrium approach was used for process simulation. Sensitivity analysis was conducted to determine the reasonable operating parameters. With a set of reasonable operating conditions, the effects of ChCl/Urea (1:2) content on the total energy utilization, the diameters and pressure drops of absorber and desorber as well as the environmental assessment of the process were studied. The simulation results showed that, with the addition of ChCl/Urea (1:2), the total energy utilization decreased by 16% compared to the process with pure water, and the diameters of both absorber and desorber decreased with increasing content of ChCl/Urea (1:2). The process using aqueous ChCl/Urea (1:2) was more environmentally benign than that with pure water. Therefore, aqueous ChCl/Urea (1:2) is a promising solvent for biogas upgrading.
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| 28. |
- Ma, Chunyan, et al.
(författare)
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Molar Enthalpy of Mixing for Choline Chloride/Urea Deep EutecticSolvent + Water System
- 2016
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Ingår i: Journal of Chemical and Engineering Data. - : American Chemical Society (ACS). - 0021-9568 .- 1520-5134. ; 61:12, s. 4172-4177
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Tidskriftsartikel (refereegranskat)abstract
- The molar enthalpies of mixing for binary systems of choline chloride (chcl)/urea deep eutectic solvents (mole ratios of 1:1.5, 1:2, and 1:2.5) with water were measured at 308.15 and 318.15 K under atmospheric pressure with an isothermal calorimeter. The binary mixture of (chcl/urea (1:2.5) + water) showed endothermic behavior over the entire range of compositions, while the binary mixtures of (chcl/urea (1:1.5) + water) and (chcl/urea (1:2) + water) showed endothermic behavior first and then was changed to be exothermic with increasing content of deep eutectic solvents. The Redlich–Kister (RK) equation and the nonrandom two-liquid (NRTL) model were used to fit experimental molar enthalpies of mixing. The NRTL model with the fitted parameters was further used to predict the vapor pressure for the three systems and was compared with the experimental data from literature. For the binary mixtures of (chcl/urea (1:2) + water), the predicted vapor pressure agreed well with the experimental data only when the temperature was lower than 333.15 K and the mole fraction of chcl/urea (1:2) was lower than 0.1. Otherwise, the deviation increased greatly with an increase of the amount of chcl/urea (1:2).
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| 29. |
- Ma, Chunyan, et al.
(författare)
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Techno-economic analysis and performance comparison of aqueous deep eutectic solvent and other physical absorbents for biogas upgrading
- 2018
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Ingår i: Applied Energy. - : Elsevier. - 0306-2619 .- 1872-9118. ; 225, s. 437-447
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Tidskriftsartikel (refereegranskat)abstract
- Biogas has been considered as an alternative renewable energy, and CO2 removal from raw biogas (i.e. biogas upgrading) is needed for producing biomethane to be used as vehicle fuels or injected into the natural gas grid. Biogas upgrading with physical absorbents, such as water and other commercial organic solvents, is simple, efficient and with low energy requirements for regeneration. Recently, deep eutectic solvents (DESs) with nonvolatility, nonflammability and low price have been reported as promising alternatives to replace conventional physical absorbents in many research areas including biogas upgrading. However, the performances of these physical solvents including conventional physical absorbents and DES-based solvents have not been evaluated and compared with each other. In this work, the properties of 4 physical solvents (i.e. water, dimethyl ether of polyethylene glycol (DEPG), propylene carbonate (PC), and aqueous DES (AQDES)) were compared. Furthermore, a conceptual process was developed to upgrade biogas with these solvents and simulated based on Aspen Plus in order to conduct performance comparison. The simulation results of energy utilization, the amount of recirculated solvents and the diameters of absorber and desorber were analyzed and compared based on equilibrium and rate-based approaches, respectively. The simulation results based on the rate-based approach were further used to estimate the costs of biogas upgrading process with a same raw biogas capacity for comparison. Meanwhile, the specific cost of biogas upgrading process with a same size of equipment was also evaluated. The results show that the CO2 solubility, selectivity and viscosity are three more important properties, providing valuable information for developing novel physical solvents for CO2 separation. The simulation results show that the equilibrium and rate-based approaches result in different conclusions, especially when the solvent viscosity is relatively high, and the rate-based approach is preferable. Based on the simulation results from the rate-based approach, the performances of AQDES and PC are similar with a same amount of energy utilization, that is around 11% lower than water, and DEPG is inferior to water. For the case with the same gas capacity, the total annual costs of biogas upgrading process with these solvents show the following order: DEPG > AQ60wt.%DES > water > AQ50wt.%DES ≈ PC. For the case with the same size of equipment, compared to water, the total specific costs of biogas upgrading process with PC and AQ50wt.%DES decrease by about 30% and 45%, respectively, and the treated biogas capacities increase to 1.5 and 2 times, respectively. In general, both PC and AQ50wt.%DES show better performance than the other solvents. Considering that DES is an environmentally benign solvent, and the performance of DES can be greatly improved by further designing, it is more promising.
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| 30. |
- Ma, Chunyan, et al.
(författare)
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The peculiar effect of water on ionic liquids and deep eutectic solvents.
- 2018
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Ingår i: Chemical Society Reviews. - : Royal Society of Chemistry. - 0306-0012 .- 1460-4744. ; 47:23, s. 8685-8720
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Forskningsöversikt (refereegranskat)abstract
- Ionic liquids (ILs) and deep eutectic solvents (DESs) have been suggested as eco-friendly alternatives to organic solvents. A trace amount of water is often unavoidable as impurity, and water is also added on purpose to reduce their problematically high viscosity and lower their high price. Understanding the distinct effects of water on the properties of ILs/DESs is highly important. In this review, we collect published experimental and theoretical results for IL/DES-H2O systems at varied water concentrations and analyze them. Results from mechanistic studies, thermodynamic modelling and advanced experiments are collected and critically discussed. Six commonly studied IL/DES-H2O systems were selected to map experimental observations onto microscopic results obtained in mechanistic studies. A great variety of distinct contours of the excess properties can be observed over the entire compositional range, indicating that the properties of IL/DES-H2O systems are highly unpredictable. Mechanistic studies clearly demonstrate that the added H2O rapidly changes the heterogeneous 3D structures of pure ILs/DESs, leading to very different properties and behaviour. There are similarities between aqueous electrolytes and IL/DES solutions but the bulky and asymmetric organic cations in ILs/DESs do not conform to the standard salt dissolution and hydration concepts. Thermodynamic modelling previously assumes ILs/DESs to be either a neutral ion-pair or completely dissociated ions, neglecting specific ion hydration effects. A new conceptual framework is suggested for thermodynamic modelling of IL/DES-H2O binary systems to enable new technologies for their practical applications.
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| 31. |
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| 32. |
- Salvo, Gloria, et al.
(författare)
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Open vs minimally invasive radical trachelectomy in early-stage cervical cancer : International Radical Trachelectomy Assessment Study
- 2022
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Ingår i: American Journal of Obstetrics and Gynecology. - : Elsevier BV. - 0002-9378 .- 1097-6868. ; 226:1, s. 1-97
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Tidskriftsartikel (refereegranskat)abstract
- Background: Minimally invasive radical trachelectomy has emerged as an alternative to open radical hysterectomy for patients with early-stage cervical cancer desiring future fertility. Recent data suggest worse oncologic outcomes after minimally invasive radical hysterectomy than after open radical hysterectomy in stage I cervical cancer. Objective: We aimed to compare 4.5-year disease-free survival after open vs minimally invasive radical trachelectomy. Study Design: This was a collaborative, international retrospective study (International Radical Trachelectomy Assessment Study) of patients treated during 2005–2017 at 18 centers in 12 countries. Eligible patients had squamous carcinoma, adenocarcinoma, or adenosquamous carcinoma; had a preoperative tumor size of ≤2 cm; and underwent open or minimally invasive (robotic or laparoscopic) radical trachelectomy with nodal assessment (pelvic lymphadenectomy and/or sentinel lymph node biopsy). The exclusion criteria included neoadjuvant chemotherapy or preoperative pelvic radiotherapy, previous lymphadenectomy or pelvic retroperitoneal surgery, pregnancy, stage IA1 disease with lymphovascular space invasion, aborted trachelectomy (conversion to radical hysterectomy), or vaginal approach. Surgical approach, indication, and adjuvant therapy regimen were at the discretion of the treating institution. A total of 715 patients were entered into the study database. However, 69 patients were excluded, leaving 646 in the analysis. Endpoints were the 4.5-year disease-free survival rate (primary), 4.5-year overall survival rate (secondary), and recurrence rate (secondary). Kaplan-Meier methods were used to estimate disease-free survival and overall survival. A post hoc weighted analysis was performed, comparing the recurrence rates between surgical approaches, with open surgery being considered as standard and minimally invasive surgery as experimental. Results: Of 646 patients, 358 underwent open surgery, and 288 underwent minimally invasive surgery. The median (range) patient age was 32 (20–42) years for open surgery vs 31 (18–45) years for minimally invasive surgery (P=.11). Median (range) pathologic tumor size was 15 (0–31) mm for open surgery and 12 (0.8–40) mm for minimally invasive surgery (P=.33). The rates of pelvic nodal involvement were 5.3% (19 of 358 patients) for open surgery and 4.9% (14 of 288 patients) for minimally invasive surgery (P=.81). Median (range) follow-up time was 5.5 (0.20–16.70) years for open surgery and 3.1 years (0.02–11.10) years for minimally invasive surgery (P<.001). At 4.5 years, 17 of 358 patients (4.7%) with open surgery and 18 of 288 patients (6.2%) with minimally invasive surgery had recurrence (P=.40). The 4.5-year disease-free survival rates were 94.3% (95% confidence interval, 91.6–97.0) for open surgery and 91.5% (95% confidence interval, 87.6–95.6) for minimally invasive surgery (log-rank P=.37). Post hoc propensity score analysis of recurrence risk showed no difference between surgical approaches (P=.42). At 4.5 years, there were 6 disease-related deaths (open surgery, 3; minimally invasive surgery, 3) (log-rank P=.49). The 4.5-year overall survival rates were 99.2% (95% confidence interval, 97.6–99.7) for open surgery and 99.0% (95% confidence interval, 79.0–99.8) for minimally invasive surgery. Conclusion: The 4.5-year disease-free survival rates did not differ between open radical trachelectomy and minimally invasive radical trachelectomy. However, recurrence rates in each group were low. Ongoing prospective studies of conservative management of early-stage cervical cancer may help guide future management.
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| 33. |
- Wang, Honglin, et al.
(författare)
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Carbon recycling – An immense resource and key to a smart climate engineering : A survey of technologies, cost and impurity impact
- 2020
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Ingår i: Renewable & sustainable energy reviews. - : Elsevier. - 1364-0321 .- 1879-0690. ; 131
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Forskningsöversikt (refereegranskat)abstract
- In order to meet climate goals, both CO2 capture and storage (CCS) and CO2 capture and utilization (CCU) have been identified as increasingly important technologies for mitigating CO2 emissions that are difficult to avoid. In this work, the CO2 utilization, or more specifically, the CO2 conversion to fuels and urea, considering the large demand for CO2, as well as the CO2 mineralization are surveyed and reviewed. The content of this review includes technologies – all the way from the laboratory studies to the industrial applications – their current status, and future potential. CCS is included for a comparison concerning the costs. Also, aspects as the CO2 impurities and the effect of it as well as various requirements concerning the CO2 impurity are included. Many recent studies show that CCU, especially CO2 conversion to fuels, will play an essential role in mitigating CO2 emissions, while developed methods and technologies are not yet mature. More research work needs to be conducted to improve the process efficiency via developing catalysts and reducing the cost of producing H2 that is used as a reactant for fuel synthesis. Moreover, current literature also shows that impurities will affect the process of both CCS and CCU, while the work of studying their influence, especially on CCU, is still scarce. The cost of CCS has been estimated combined with impurities, while studies on cost estimation for CCU are still limited, and the cost, in general, is relatively high with the currently available technologies.
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| 34. |
- Wang, Xiaohua, et al.
(författare)
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Tacrolimus Causes Hypertension by Increasing Vascular Contractility via RhoA (Ras Homolog Family Member A)/ROCK (Rho-Associated Protein Kinase) Pathway in Mice
- 2022
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Ingår i: Hypertension. - : Ovid Technologies (Wolters Kluwer Health). - 0194-911X .- 1524-4563. ; 79:10, s. 2228-2238
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Tidskriftsartikel (refereegranskat)abstract
- Background: To provide tacrolimus is first-line treatment after liver and kidney transplantation. However, hypertension and nephrotoxicity are common tacrolimus side effects that limit its use. Although tacrolimus-related hypertension is well known, the underlying mechanisms are not. Here, we test whether tacrolimus-induced hypertension involves the RhoA (Ras homolog family member A)/ROCK (Rho-associated protein kinase) pathway in male C57Bl/6 mice. methods: Intra-arterial blood pressure was measured under anesthesia. The reactivity of renal afferent arterioles and mesenteric arteries were assessed in vitro using microperfusion and wire myography, respectively. Results: Tacrolimus induced a transient rise in systolic arterial pressure that was blocked by the RhoA/ROCK inhibitor Fasudil (12.0 +/- 0.9 versus 3.2 +/- 0.7; P<0.001). Moreover, tacrolimus reduced the glomerular filtration rate, which was also prevented by Fasudil (187 +/- 20 versus 281 +/- 8.5; P<0.001). Interestingly, tacrolimus enhanced the sensitivity of afferent arterioles and mesenteric arteries to Ang II (angiotensin II), likely due to increased intracellular Ca2+ mobilization and sensitization. Fasudil prevented increased Ang II-sensitivity and blocked Ca2+ mobilization and sensitization. Preincubation of mouse aortic vascular smooth muscle cells with tacrolimus activated the RhoA/ROCK/MYPT-1 (myosin phosphatase targeting subunit 1) pathway. Further, tacrolimus increased cytoplasmic reactive oxygen species generation in afferent arterioles (107 +/- 5.9 versus 163 +/- 6.4; P<0.001) and in cultured mouse aortic vascular smooth muscle cells (100 +/- 7.5 versus 160 +/- 23.2; P<0.01). Finally, the reactive oxygen species scavenger Tempol inhibited tacrolimus-induced Ang II hypersensitivity in afferent arterioles and mesenteric arteries. Conclusions: The RhoA/ROCK pathway may play an important role in tacrolimus-induced hypertension by enhancing Ang II-specific vasoconstriction, and reactive oxygen species may participate in this process by activating the RhoA/ROCK pathway.
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| 35. |
- Wang, Yanxin, et al.
(författare)
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Thermodynamic Study of Choline Chloride-Based Deep Eutectic Solvents with Water and Methanol
- 2020
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Ingår i: Journal of Chemical and Engineering Data. - : American Chemical Society (ACS). - 0021-9568 .- 1520-5134. ; 65:5, s. 2446-2457
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Tidskriftsartikel (refereegranskat)abstract
- To study the effects of type and content of cosolvent as well as temperature on the properties of two well-known deep eutectic solvents (DESs), i.e., ChCl/EG (choline chloride + ethylene glycol at a molar ratio of 1:2) and ChCl/Gly (choline chloride and glycerol at a molar ratio of 1:2), the density and viscosity of the mixtures of ChCl/EG or ChCl/Gly with methanol (MeOH) and water (H2O) over the whole compositional range at temperatures from 288.15 to 323.15 K as well as the molar enthalpy of mixing for the mixtures of ChCl/EG or ChCl/Gly + MeOH were experimentally measured. The excess molar volume, viscosity deviation, and excess molar Gibbs energy of activation were further calculated to study the effects of temperature, types of cosolvent and DES, and their contents on the nonideal behavior of these pseudobinary systems. The molar enthalpy of mixing measured in this work was further compared with those with H2O as the cosolvent reported in the literature. It shows that the mixing of these two DESs with MeOH is exothermic, which is opposite compared to those mixed with H2O. Additionally, the nonrandom two-liquid model and Gibbs–Helmholtz equation were combined to represent the experimental results of the enthalpy of mixing.
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| 36. |
- Wang, Ze, et al.
(författare)
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Experimental investigation of internal structures of NH3/H2/O2/N2 premixed jet flames using multi-scalar imaging
- 2024
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Ingår i: Proceedings of the Combustion Institute. - 1540-7489. ; 40:1-4
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Tidskriftsartikel (refereegranskat)abstract
- Ammonia-hydrogen (NH3-H2) blends stand as a promising carbon-neutral fuel alternative. This study delves into the variation in the internal structure of NH3-H2 flames with varying Lewis numbers (Le) and turbulence intensities. Simultaneous multi-scalar imaging of NH3/NH/OH was performed to characterize the structures of turbulent jet flames with the same unstretched laminar flame speed (30.8 cm/s) but different H2 contents. Internal flame structures were characterized by isocontours of NH3, NH (both inner and outer edges, NHi and NHo), and OH to delimit the reaction zone. The parallelism of the selected isocontours (i.e., NH3, NHi, and NHo) with the OH baseline was quantified by calculating the probabilities, P(δp), of the selected isocontours overlapping with the OH baseline shifted by a distance of δp along its normal direction. On the one hand, results have revealed that increasing turbulence disrupts the parallelism of the selected isocontours with the OH baseline, leading to a larger and FWHM, as well as a reduced skewness of the P(δp) profiles. On the other hand, flames with higher H2 content and lower Le exhibit great resistance to turbulence but experience enhanced wrinkling due to the differential diffusion effect, which can also cause deviations in scalar parallelism at low turbulence intensity. For flames with reduced Le numbers, the NH3 isocontours are observed to be located even downstream of the NHi isocontours, which belong to the reaction zone. The extent of parallelism for the selected isocontours within the reaction zone is found to respond to turbulence and Le differently, deviating from an idealized picture of the flamelet manifold.
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| 37. |
- Wu, Nanhua, et al.
(författare)
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Confinement Phenomenon Effect on the CO2 Absorption Working Capacity in Ionic Liquids Immobilized into Porous Solid Supports
- 2017
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Ingår i: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 33:42, s. 11719-11726
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Tidskriftsartikel (refereegranskat)abstract
- In this work, the CO2 absorption working capacity and solubility in the ionic liquids immobilized into porous solid materials (substrates) was studied both experimentally and theoretically. The CO2 absorption working capacity in the immobilized ionic liquids was measured experimentally. It was found that the CO2 absorption working capacity and solubility increased up to 10 times compared to that in the bulk ionic liquids when the film thickness is nearly 2.5 nm in the [HMIm][NTf2] immobilized into the P25. Meanwhile, a new model was proposed to describe the Gibbs free energy of CO2 in the immobilized ionic liquids, and both macro- and micro-analyses of the CO2 solubility in the confined ionic liquids were conducted. The theoretical investigations reveal that the substrate has a crucial effect on the gas solubility in the ionic liquid immobilized into the substrates, and the model performance was approved with the consideration of substrate effect.
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| 38. |
- Wu, Nanhua, et al.
(författare)
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Generalized Gibbs free energy of confined nanoparticles
- 2017
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Ingår i: AIChE Journal. - : John Wiley & Sons. - 0001-1541 .- 1547-5905. ; 63:10, s. 4595-4603
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Tidskriftsartikel (refereegranskat)abstract
- The nanoparticles generally show abnormal properties compared to those in the bulk phase, and they exhibit significant potential in various applications such as catalysis and energy conversion. However, the theoretical work for describing the properties of nanoparticles is limited with poor prediction capacity. In this work, the Gibbs free energy was studied, from both macroscope and microscope, predictive models were proposed to study the thermodynamic properties of nanoparticles with a generalized description of the Gibbs free energy considering the effects of surface-energy and the substrate contacted. The proposed model from the microscope was based on the corresponding states theory to describe the effect of the substrate on the Gibbs free energy of nanoparticles, in which the molecular parameter with a generalized constant was obtained from the melting point of metals due to sufficient experimental information. The comparison with the new measured experimental results proves the reliability of the model prediction
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