| 1. |
- Björling, Marcus, et al.
(författare)
-
Elastohydrodynamic performance of a bio-based, non-corrosive ionic liquid
- 2017
-
Ingår i: Applied Sciences. - : MDPI. - 2076-3417. ; 17:10
-
Tidskriftsartikel (refereegranskat)abstract
- To improve performance of machine components, lubrication is one of the most important factors. Especially for use in extreme environments, researchers look for other solutions rather than common lubricant base stocks like mineral oils or vegetable oils. One such example is ionic liquids. Ionic liquids have been defined as molten salts with melting points below 100 °C that are entirely ionic in nature, comprising both cationic and anionic species. The industrial use of ionic liquids is mostly as solvents, electrolytes, extractants and catalysts. In tribological applications, ionic liquids are mainly studied in boundary lubrication and in pure sliding contacts. In this work, the elastohydrodynamic performance of a bio-based, non-corrosive, [choline][L-proline] ionic liquid is evaluated in terms of pressure-viscosity response, film forming capability and friction. The results show a pressure-viscosity coefficient of below 8 GPa-1 at 25 °C, among the lowest reported for any ionic liquid. The ionic liquid generated up to 70% lower friction than a reference paraffin oil with a calculated difference in film thickness of 11%. It was also shown that this ionic liquid is very hygroscopic, which is believed to explain part of the low friction results, but also has to be considered in practical applications since the water content will influence the properties and thus the performance of the lubricant.
|
|
| 2. |
- Björling, Marcus, et al.
(författare)
-
Elastohydrodynamic Performance of a Non-Corrosive Non-Protic Ionic Liquid
- 2017
-
Konferensbidrag (refereegranskat)abstract
- Ionic liquids have been defined as molten salts with melting points below 100 degrees C that are entirely ionic in nature, comprising both cationic and anionic species. The industrial use of ionic liquids is mostly as solvents, electrolytes, extractants and catalysts. In tribological applications, Ionic liquids are mainly studied in boundary lubrication and in pure sliding contacts. In this work, the elastohydrodynamic performance of a non-corrosive, non-protonic ionic liquid is studied to assess the feasibility to use this kind of ionic liquid in machine components such as gears, rolling bearings and cam followers. This study includes ball on disc friction experiments in rolling sliding full film elastohydrodynamic lubrication at high slide to roll ratios, as well as film thickness measurements with optical interferometry. A commercially available paraffin oil has been used as a reference.
|
|
| 3. |
- Cao, Danyang, et al.
(författare)
-
Biolubricant
- 2023
-
Ingår i: Sustainable Production Innovations. - : John Wiley & Sons. ; , s. 1-56
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)
|
|
| 4. |
- Chen, Jingjing, et al.
(författare)
-
Slippage on Porous Spherical Superhydrophobic Surface Revolutionizes Heat Transfer of Non-Newtonian Fluid
- 2022
-
Ingår i: Advanced Materials Interfaces. - : John Wiley & Sons. - 2196-7350. ; 9:34
-
Tidskriftsartikel (refereegranskat)abstract
- In this study, a new strategy to achieve high-efficient heat transfer for non-Newtonian fluids with slippage using a stably prepared superhydrophobic coating is presented. A superhydrophobic coating is prepared on the inner surface of a sleeve at specific shear stress. The slippage and heat-transfer processes of the typical non-Newtonian fluid–1% carboxymethyl cellulose solutions on the superhydrophobic coating are investigated simultaneously. A novel porous spherical type of superhydrophobic coating with a contact angle of 168° is obtained. It is found that the shear stress in electrodeposition is a key parameter to control the morphology and wetting ability of the superhydrophobic coating. The slip length and enhancement factor of heat transfer for the non-Newtonian fluid on the coating are found in a range of 20–900 µm and 1.47 experimentally. A new parameter is proposed as Reynolds number Re divided by the dimensionless slip length ls* (Re/ls*) for the heat-transfer enhancement with slippage, which can be used as the guide for designing coating and selecting the operating conditions. The Re/ls* is <4, which can enhance the heat transfer via the slippage.
|
|
| 5. |
- Chen, Long, et al.
(författare)
-
Facile synthesis of mesoporous carbon nanocomposites from natural biomass for efficient dye adsorption and selective heavy metal removal
- 2016
-
Ingår i: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 6:3, s. 2259-2269
-
Tidskriftsartikel (refereegranskat)abstract
- Mesoporous carbon with embedded iron carbide nanoparticles was successfully synthesized via a facile impregnation–carbonization method. A green biomass resource, cotton fabric, was used as a carbon precursor and an iron precursor was implanted to create mesopores through a catalytic graphitization reaction. The pore structure of the nanocomposites can be tuned by adjusting the iron precursor loadings and the embedded iron carbide nanoparticles serve as an active component for magnetic separation after adsorption. The microstructure of the nanocomposites was carefully investigated by various characterization techniques including electron microscopy, X-ray diffraction, surface analyzer, magnetic property analyzer and etc. The newly created mesopores are demonstrated as a critical component to enhance the adsorption capacity of organic dyes and embedded iron carbide nanoparticles are responsible for the selective removal of heavy metal ions (Zn2+, Cu2+, Ni2+, Cr6+ and Pb2+). Isotherm adsorption, kinetic study at three different temperatures (25, 45 and 65 °C) and cycling retention tests were performed to understand the adsorptive behavior of the nanocomposites with organic dyes (methylene blue and methyl orange). Together with the preferable removal of more toxic heavy metal species (Cr6+ and Pb2+), these mesoporous nanocomposites show promising applications in pollutant removal from water. The facile material preparation allows convenient scale-up manufacturing with low cost and minimum environmental impact.
|
|
| 6. |
- Chen, Long, et al.
(författare)
-
Pore size dependent molecular adsorption of cationic dye in biomass derived hierarchically porous carbon
- 2017
-
Ingår i: Journal of Environmental Management. - : Elsevier. - 0301-4797 .- 1095-8630. ; 196, s. 168-177
-
Tidskriftsartikel (refereegranskat)abstract
- Hierarchically porous carbon adsorbents were successfully fabricated from different biomass resources (softwood, hardwood, bamboo and cotton) by a facile two-step process, i.e. carbonization in nitrogen and thermal oxidation in air. Without involving any toxic/corrosive chemicals, large surface area of up to 890 m2/g was achieved, which is comparable to commercial activated carbon. The porous carbons with various surface area and pore size were used as adsorbents to investigate the pore size dependent adsorption phenomenon. Based on the density functional theory, effective (E-SSA) and ineffective surface area (InE-SSA) was calculated considering the geometry of used probing adsorbate. It was demonstrated that the adsorption capacity strongly depends on E-SSA instead of total surface area. Moreover, a regression model was developed to quantify the adsorption capacities contributed from E-SSA and InE-SSA, respectively. The applicability of this model has been verified by satisfactory prediction results on porous carbons prepared in this work as well as commercial activated carbon. Revealing the pore size dependent adsorption behavior in these biomass derived porous carbon adsorbents will help to design more effective materials (either from biomass or other carbon resources) targeting to specific adsorption applications.
|
|
| 7. |
- Dai, B., et al.
(författare)
-
Effect of the composition of biomass on the quality of syngas produced from thermochemical conversion based on thermochemical data prediction
- 2019
-
Ingår i: Energy & Fuels. - : American Chemical Society (ACS). - 0887-0624 .- 1520-5029. ; 33:6, s. 5253-5262
-
Tidskriftsartikel (refereegranskat)abstract
- Syngas produced from thermochemical conversion of biomass has been given more attention because it can be converted to a variety of fuels and chemicals as substitutes for petroleum-based chemicals via the Fischer–Tropsch process. In this study, one wheat straw and its element content fluctuation in the feasible range are selected as samples first to study the effect of the biomass composition on the quality of syngas produced. Then, the thermochemical data (standard molar enthalpy of formation, standard molar entropy, and heat capacity) of samples are predicted by highly accurate prediction models. Thermochemical conversions of the samples are simulated by the Gibbs energy minimization method based on the results of thermochemical data prediction. At last, the effect of the biomass composition on the resource index (amounts of CO and H2 and ratio of H2/CO) and energy index (lower heat value) of syngas is calculated and analyzed. This study provides a method to obtain the relationship between the composition of biomass and the quality of syngas produced.
|
|
| 8. |
- Fan, Jing, et al.
(författare)
-
Hybrid data-driven and physics-based modeling for viscosity prediction of ionic liquids
- 2024
-
Ingår i: Green Energy & Environment. - : Elsevier. - 2468-0257.
-
Tidskriftsartikel (refereegranskat)abstract
- Viscosity is one of the most important fundamental properties of fluids. However, accurate acquisition of viscosity for ionic liquids (ILs) remains a critical challenge. In this study, an approach integrating prior physical knowledge into the machine learning (ML) model was proposed to predict the viscosity reliably. The method was based on 16 quantum chemical descriptors determined from the first principles calculations and used as the input of the ML models to represent the size, structure, and interactions of the ILs. Three strategies based on the residuals of the COSMO-RS model were created as the output of ML, where the strategy directly using experimental data was also studied for comparison. The performance of six ML algorithms was compared in all strategies, and the CatBoost model was identified as the optimal one. The strategies employing the relative deviations were superior to that using the absolute deviation, and the relative ratio revealed the systematic prediction error of the COSMO-RS model. The CatBoost model based on the relative ratio achieved the highest prediction accuracy on the test set (R2 = 0.9999, MAE = 0.0325), reducing the average absolute relative deviation (AARD) in modeling from 52.45 % to 1.54 %. Features importance analysis indicated the average energy correction, solvation-free energy, and polarity moment were the key influencing the systematic deviation.
|
|
| 9. |
- Ji, Tuo, et al.
(författare)
-
Green Processing of Plant Biomass into Mesoporous Carbon as Catalyst Support
- 2016
-
Ingår i: Chemical Engineering Journal. - : Elsevier BV. - 1385-8947 .- 1873-3212. ; 295, s. 301-308
-
Tidskriftsartikel (refereegranskat)abstract
- Four different plant biomass, bamboo, cotton, soft wood and hard wood, were utilized as carbon precursors to fabricate porous carbon catalyst supports via a chemical free approach. Large surface area with unique mesoporous structure was successfully created in the carbon, which made them suitable for catalyst support. After decorating silver nanoparticles onto these carbon supports, nitroaromatics reduction reactions were performed to evaluate the catalyst activity. Results indicate that chemical composition and surface groups of carbon supports determine the metal catalyst nucleation/growth while the porous microstructure of support affects the mass transport of reactant/product across the liquid/catalyst interface. Among the four selected biomass, porous carbon manufactured from soft wood acquires the highest average pore size, pore volume, mesopore volume fraction and best catalytic activity after decorating silver nanoparticles. This work not only presents an environmental benign process that converts natural biomass into effective porous carbon catalyst supports, but also offers a comprehensive understanding of biomass structure/composition relating to their suitability as catalyst support.
|
|
| 10. |
- Jiang, Guancong, et al.
(författare)
-
Critical Role of Carbonized Cellulose in the Evolution of Highly Porous Biocarbon : Seeing the Structural and Compositional Changes of Spent Mushroom Substrate by Deconvoluted Thermogravimetric Analysis
- 2020
-
Ingår i: Industrial & Engineering Chemistry Research. - : American Chemical Society (ACS). - 0888-5885 .- 1520-5045. ; 59:52, s. 22541-22548
-
Tidskriftsartikel (refereegranskat)abstract
- Structural optimization of activated carbon (AC) mainly relies on experience, which depends on the intrinsic structure of biochar, processing conditions, and the interplay of both parties. A fundamental understanding of the pore structure evolution related to the intrinsic structure and composition remains a challenge. In this work, spent mushroom substrate, a rapidly growing byproduct of the mushroom cultivation industry, is used as model biomass to prepare AC under CO2 activation. The structure and composition of the AC products with different activation durations were systematically analyzed with several characterization techniques including N2 adsorption–desorption, scanning electron microscopy, X-ray diffraction, and Raman spectroscopy. A multipeak separation method is developed that enables quantitative analysis of carbonized lignin and carbonized cellulose. A peak area ratio parameter is proposed to describe the retention of cellulose. It is revealed that higher retention of carbonized cellulose corresponds to a larger Brunauer–Emmett–Teller (BET) surface area, demonstrating the dominant role of cellulose in the pore structure development process. This work not only provides a qualitative correlation between cellulose and rich porous structure but also offers a new quantitative tool to understand the structure–composition relationship during the pore evolution process.
|
|
