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Articles 1 - 8 of 8
Full-Text Articles in Social and Behavioral Sciences
Chemistry Of Hydrogen Oxide Radicals (Hox) In The Arctic Troposphere In Spring, J Mao, D J. Jacob, M J. Evans, J R. Olson, X Ren, W H. Brune, T M. St. Clair, J D. Crounse, K M. Spencer, M R. Beaver, P O. Wennberg, M J. Cubison, J L. Jimenez, A Fried, P Weibring, J G. Walega, S R. Hall, A J. Weinheimer, R C. Cohen, G Chen, J H. Crawford, C Mcnaughton, A D. Clarke, L Jaegle, Jenny A. Fisher, R M. Yantosca, P Le Sager, C C. Carouge
Chemistry Of Hydrogen Oxide Radicals (Hox) In The Arctic Troposphere In Spring, J Mao, D J. Jacob, M J. Evans, J R. Olson, X Ren, W H. Brune, T M. St. Clair, J D. Crounse, K M. Spencer, M R. Beaver, P O. Wennberg, M J. Cubison, J L. Jimenez, A Fried, P Weibring, J G. Walega, S R. Hall, A J. Weinheimer, R C. Cohen, G Chen, J H. Crawford, C Mcnaughton, A D. Clarke, L Jaegle, Jenny A. Fisher, R M. Yantosca, P Le Sager, C C. Carouge
Jenny A Fisher
We use observations from the April 2008 NASA ARCTAS aircraft campaign to the North American Arctic, interpreted with a global 3-D chemical transport model (GEOS-Chem), to better understand the sources and cycling of hydrogen oxide radicals (HOx≡H+OH+peroxy radicals) and their reservoirs (HOy≡HOx+peroxides) in the springtime Arctic atmosphere. We find that a standard gas-phase chemical mechanism overestimates the observed HO2 and H2O2 concentrations. Computation of HOx and HOy gas-phase chemical budgets on the basis of the aircraft observations also indicates a large missing sink for both. We hypothesize that this could reflect HO2 uptake by aerosols, favored by low temperatures and …
Dependence Of Texture Development On The Grain Size Of Tertiary Oxide Scales Formed On A Microalloyed Steel, Xianglong Yu, Zhengyi Jiang, Jingwei Zhao, Dongbin Wei, Ji Zhou, Cunlong Zhou, Qingxue Huang
Dependence Of Texture Development On The Grain Size Of Tertiary Oxide Scales Formed On A Microalloyed Steel, Xianglong Yu, Zhengyi Jiang, Jingwei Zhao, Dongbin Wei, Ji Zhou, Cunlong Zhou, Qingxue Huang
Faculty of Engineering and Information Sciences - Papers: Part A
Both orientational and geometrical characteristics of grains in tertiary oxide scales have been quantitatively investigated using the electron backscatter diffraction (EBSD) technique. Phase and orientation mappings demonstrate that the {001} planes of magnetite and the {0001} planes of hematite are parallel to the direction of oxide growth. Pole figures (PFs) as scattering plots clearly display the direct correlation between the orientations and microstructure sites of magnetite grains. Magnetite grains develop a strong rotated cube texture component that shifts to the {100} component, whereas those with the grain size of 1-5. μm develop the {001} cube texture component. The refined magnetite …
Oxide Scale Characterization Of Ferritic Stainless Steel And Its Deformation And Friction In Hot Rolling, Xiawei Cheng, Zhengyi Jiang, Dongbin Wei, Liang Hao, Jingwei Zhao, Laizhu Jiang
Oxide Scale Characterization Of Ferritic Stainless Steel And Its Deformation And Friction In Hot Rolling, Xiawei Cheng, Zhengyi Jiang, Dongbin Wei, Liang Hao, Jingwei Zhao, Laizhu Jiang
Faculty of Engineering and Information Sciences - Papers: Part A
The oxidation kinetics of ferritic stainless steel 430 was studied in dry and humid air at 1090 °C by Thermo Gravimetric Analysis (TGA). Different atmospheres and heating times were adopted for reheating to obtain different compositions and thickness of the oxide scale. Hot rolling was performed on a 2-high Hille 100 experimental rolling mill at various reductions. Oxide scale thickness and composition were analysed with optical microscopy (OM), scanning electron microscope (SEM) and X-ray diffraction (XRD). The surface profiles were examined by a digital microscope, and the topographic features of the thin oxide scale surface were examined with an atomic …
Dynamic Wetting Of Cao-Al2o3-Sio2-Mgo Liquid Oxide On Mgal2o4 Spinel, Hamed Abdeyazdan, Neslihan Dogan, Muhammad Rhamdhani, Michael Chapman, Brian Monaghan
Dynamic Wetting Of Cao-Al2o3-Sio2-Mgo Liquid Oxide On Mgal2o4 Spinel, Hamed Abdeyazdan, Neslihan Dogan, Muhammad Rhamdhani, Michael Chapman, Brian Monaghan
Faculty of Engineering and Information Sciences - Papers: Part A
Inclusion type and content in steel is critical in steelmaking, affecting both productivity through clogging, and downstream physical properties of the steel. They are normally removed from steel by reacting with a slag (liquid oxide) phase. For efficient inclusion removal, the inclusions must attach/bond with this liquid phase. The strength of the attachment can be in part characterized by the wettability of the liquid oxide on the inclusions. In this study, the dynamic wetting of liquid oxides of the CaO-Al2O3-SiO2-MgO system on a solid spinel (MgAl2O4) substrate with low porosity of 1.9 pct was measured at 1773 K (1500 °C) …
Effect Of Extreme Pressure Additives On The Deformation Behavior Of Oxide Scale During The Hot Rolling Of Ferritic Stainless Steel Strips, Liang Hao, Zhengyi Jiang, Xiawei Cheng, Jingwei Zhao, Dongbin Wei, Laizhu Jiang, Suzhen Luo, Ming Luo, Li Ma
Effect Of Extreme Pressure Additives On The Deformation Behavior Of Oxide Scale During The Hot Rolling Of Ferritic Stainless Steel Strips, Liang Hao, Zhengyi Jiang, Xiawei Cheng, Jingwei Zhao, Dongbin Wei, Laizhu Jiang, Suzhen Luo, Ming Luo, Li Ma
Faculty of Engineering and Information Sciences - Papers: Part A
High-speed steel (HSS) materials are universally used as work rolls for the hot rolling of stainless steels. Their use has increased the output of the rolling mill and decreased roll material consumption and grinding. Sticking defects often occur, however, during the hot rolling process. In this article, extreme pressure (EP) additives were dropped on the HSS samples at high temperature. Zinc dialkyl dithiophosphate (ZDDP) was chosen as the most effective EP additive by scratch tests on the HSS samples. In order to determine the optimum proportion of ZDDP in the lubricant, two reduction rates were tested on a Hille 100 …
Local Strain Analysis Of The Tertiary Oxide Scale Formed On A Hot-Rolled Steel Strip Via Ebsd, Xianglong Yu, Zhengyi Jiang, Jingwei Zhao, Dongbin Wei, Ji Zhou, Cunlong Zhou, Qingxue Huang
Local Strain Analysis Of The Tertiary Oxide Scale Formed On A Hot-Rolled Steel Strip Via Ebsd, Xianglong Yu, Zhengyi Jiang, Jingwei Zhao, Dongbin Wei, Ji Zhou, Cunlong Zhou, Qingxue Huang
Faculty of Engineering and Information Sciences - Papers: Part A
This work presents a fine microstructure and local misorientation study of various oxide phases in the tertiary oxide scale formed on a hot-rolled steel strip via electron back-scattering diffraction (EBSD). Local strain in individual grains of four phases, ferrite (α-Fe), wustite (FeO), magnetite (Fe3O4) and hematite (α-Fe2O3), has been systematically analysed. The results reveal that Fe3O4 has a lower local strain than α-Fe2O3, in particular, on the surface and inner layers of the oxide scale. The multiphase oxides along the cracking or α-Fe2O …
Thin Film Lubrication Of Hexadecane Confined By Iron And Iron Oxide Surfaces: A Crucial Role Of Surface Structure, Thi Dinh Ta, A Kiet Tieu, Hongtao Zhu, Buyung Kosasih
Thin Film Lubrication Of Hexadecane Confined By Iron And Iron Oxide Surfaces: A Crucial Role Of Surface Structure, Thi Dinh Ta, A Kiet Tieu, Hongtao Zhu, Buyung Kosasih
Faculty of Engineering and Information Sciences - Papers: Part A
A comparative analysis of thin film lubrication of hexadecane between different iron and its oxide surfaces has been carried out using classical molecular dynamic simulation. An ab initio force-field, COMPASS, was applied for n-hexadecane using explicit atom model. An effective potential derived from density functional theory calculation was utilized for the interfacial interaction between hexadecane and the tribo-surfaces. A quantitative surface parameterization was introduced to investigate the influence of surface properties on the structure, rheological properties, and tribological performance of the lubricant. The results show that although the wall-fluid attraction of hexadecane on pure iron surfaces is significantly stronger than …
Effects Of Grain Boundaries In Oxide Scale On Tribological Properties Of Nanoparticles Lubrication, Xianglong Yu, Zhengyi Jiang, Jingwei Zhao, Dongbin Wei, Cunlong Zhou, Qingxue Huang
Effects Of Grain Boundaries In Oxide Scale On Tribological Properties Of Nanoparticles Lubrication, Xianglong Yu, Zhengyi Jiang, Jingwei Zhao, Dongbin Wei, Cunlong Zhou, Qingxue Huang
Faculty of Engineering and Information Sciences - Papers: Part A
The characters of grain boundaries in oxide layers formed on substrates influence adhesion and friction behaviour, surface fracture and wear during high temperature steel processing. In this work, an electron backscattered diffraction (EBSD) analysis was conducted to investigate the role of surface grain boundary and orientation in magnetite (Fe3O4)/haematite (α-Fe2O3) scale during hot rolling, and further evaluate their effects on tribological properties of water-based nanoparticles lubrication. The results demonstrate that Fe3O4 (100) plane is strongly sensitive to the surface characteristics as the minimisation of surface energy. Coincident site lattice …