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Lloyd L Lee - One of the best experts on this subject based on the ideXlab platform.
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boundary slip and wetting properties oF interFaces correlation oF the contact angle with the slip length
Journal of Chemical Physics, 2006Co-Authors: Roman S Voronov, Dimitrios V Papavassiliou, Lloyd L LeeAbstract:Correlations between contact angle, a measure oF the wetting oF surFaces, and slip length are developed using nonequilibrium molecular dynamics For a Lennard-Jones Fluid in Couette Flow between graphitelike hexagonal-lattice walls. The Fluid-wall interaction is varied by modulating the interFacial energy parameter er=esF∕eFF and the size parameter σr=σsF∕σFF, (s=solid, F=Fluid) to achieve hydrophobicity (solvophobicity) or hydrophilicity (solvophilicity). The eFFects oF surFace chemistry, as well as the eFFects oF temperature and shear rate on the slip length are determined. The contact angle increases From 25° to 147° on highly hydrophobic surFaces (as er decreases From 0.5 to 0.1), as expected. The slip length is Functionally dependent on the aFFinity strength parameters er and σr: increasing logarithmically with decreasing surFace energy er (i.e., more hydrophobic), while decreasing with power law with decreasing size σr. The mechanism For the latter is diFFerent From the energetic case. While weak wal...
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boundary slip and wetting properties oF interFaces correlation oF the contact angle with the slip length
Journal of Chemical Physics, 2006Co-Authors: Roman S Voronov, Dimitrios V Papavassiliou, Lloyd L LeeAbstract:Correlations between contact angle, a measure oF the wetting oF surFaces, and slip length are developed using nonequilibrium molecular dynamics For a Lennard-Jones Fluid in Couette Flow between graphitelike hexagonal-lattice walls. The Fluid-wall interaction is varied by modulating the interFacial energy parameter epsilonr=epsilonsFepsilonFF and the size parameter sigmar=sigmasFsigmaFF, (s=solid, F=Fluid) to achieve hydrophobicity (solvophobicity) or hydrophilicity (solvophilicity). The eFFects oF surFace chemistry, as well as the eFFects oF temperature and shear rate on the slip length are determined. The contact angle increases From 25 degrees to 147 degrees on highly hydrophobic surFaces (as epsilonr decreases From 0.5 to 0.1), as expected. The slip length is Functionally dependent on the aFFinity strength parameters epsilonr and sigmar: increasing logarithmically with decreasing surFace energy epsilonr (i.e., more hydrophobic), while decreasing with power law with decreasing size sigmar. The mechanism For the latter is diFFerent From the energetic case. While weak wall Forces (small epsilonr) produce hydrophobicity, larger sigmar smoothes out the surFace roughness. Both tend to increase the slip. The slip length grows rapidly with a high shear rate, as wall velocity increases three decades From 100 to 10(5) ms. We demonstrate that Fluid-solid interFaces with low epsilonr and high sigmar should be chosen to increase slip and are prime candidates For drag reduction.
Roman S Voronov - One of the best experts on this subject based on the ideXlab platform.
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boundary slip and wetting properties oF interFaces correlation oF the contact angle with the slip length
Journal of Chemical Physics, 2006Co-Authors: Roman S Voronov, Dimitrios V Papavassiliou, Lloyd L LeeAbstract:Correlations between contact angle, a measure oF the wetting oF surFaces, and slip length are developed using nonequilibrium molecular dynamics For a Lennard-Jones Fluid in Couette Flow between graphitelike hexagonal-lattice walls. The Fluid-wall interaction is varied by modulating the interFacial energy parameter er=esF∕eFF and the size parameter σr=σsF∕σFF, (s=solid, F=Fluid) to achieve hydrophobicity (solvophobicity) or hydrophilicity (solvophilicity). The eFFects oF surFace chemistry, as well as the eFFects oF temperature and shear rate on the slip length are determined. The contact angle increases From 25° to 147° on highly hydrophobic surFaces (as er decreases From 0.5 to 0.1), as expected. The slip length is Functionally dependent on the aFFinity strength parameters er and σr: increasing logarithmically with decreasing surFace energy er (i.e., more hydrophobic), while decreasing with power law with decreasing size σr. The mechanism For the latter is diFFerent From the energetic case. While weak wal...
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boundary slip and wetting properties oF interFaces correlation oF the contact angle with the slip length
Journal of Chemical Physics, 2006Co-Authors: Roman S Voronov, Dimitrios V Papavassiliou, Lloyd L LeeAbstract:Correlations between contact angle, a measure oF the wetting oF surFaces, and slip length are developed using nonequilibrium molecular dynamics For a Lennard-Jones Fluid in Couette Flow between graphitelike hexagonal-lattice walls. The Fluid-wall interaction is varied by modulating the interFacial energy parameter epsilonr=epsilonsFepsilonFF and the size parameter sigmar=sigmasFsigmaFF, (s=solid, F=Fluid) to achieve hydrophobicity (solvophobicity) or hydrophilicity (solvophilicity). The eFFects oF surFace chemistry, as well as the eFFects oF temperature and shear rate on the slip length are determined. The contact angle increases From 25 degrees to 147 degrees on highly hydrophobic surFaces (as epsilonr decreases From 0.5 to 0.1), as expected. The slip length is Functionally dependent on the aFFinity strength parameters epsilonr and sigmar: increasing logarithmically with decreasing surFace energy epsilonr (i.e., more hydrophobic), while decreasing with power law with decreasing size sigmar. The mechanism For the latter is diFFerent From the energetic case. While weak wall Forces (small epsilonr) produce hydrophobicity, larger sigmar smoothes out the surFace roughness. Both tend to increase the slip. The slip length grows rapidly with a high shear rate, as wall velocity increases three decades From 100 to 10(5) ms. We demonstrate that Fluid-solid interFaces with low epsilonr and high sigmar should be chosen to increase slip and are prime candidates For drag reduction.
Dimitrios V Papavassiliou - One of the best experts on this subject based on the ideXlab platform.
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boundary slip and wetting properties oF interFaces correlation oF the contact angle with the slip length
Journal of Chemical Physics, 2006Co-Authors: Roman S Voronov, Dimitrios V Papavassiliou, Lloyd L LeeAbstract:Correlations between contact angle, a measure oF the wetting oF surFaces, and slip length are developed using nonequilibrium molecular dynamics For a Lennard-Jones Fluid in Couette Flow between graphitelike hexagonal-lattice walls. The Fluid-wall interaction is varied by modulating the interFacial energy parameter er=esF∕eFF and the size parameter σr=σsF∕σFF, (s=solid, F=Fluid) to achieve hydrophobicity (solvophobicity) or hydrophilicity (solvophilicity). The eFFects oF surFace chemistry, as well as the eFFects oF temperature and shear rate on the slip length are determined. The contact angle increases From 25° to 147° on highly hydrophobic surFaces (as er decreases From 0.5 to 0.1), as expected. The slip length is Functionally dependent on the aFFinity strength parameters er and σr: increasing logarithmically with decreasing surFace energy er (i.e., more hydrophobic), while decreasing with power law with decreasing size σr. The mechanism For the latter is diFFerent From the energetic case. While weak wal...
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boundary slip and wetting properties oF interFaces correlation oF the contact angle with the slip length
Journal of Chemical Physics, 2006Co-Authors: Roman S Voronov, Dimitrios V Papavassiliou, Lloyd L LeeAbstract:Correlations between contact angle, a measure oF the wetting oF surFaces, and slip length are developed using nonequilibrium molecular dynamics For a Lennard-Jones Fluid in Couette Flow between graphitelike hexagonal-lattice walls. The Fluid-wall interaction is varied by modulating the interFacial energy parameter epsilonr=epsilonsFepsilonFF and the size parameter sigmar=sigmasFsigmaFF, (s=solid, F=Fluid) to achieve hydrophobicity (solvophobicity) or hydrophilicity (solvophilicity). The eFFects oF surFace chemistry, as well as the eFFects oF temperature and shear rate on the slip length are determined. The contact angle increases From 25 degrees to 147 degrees on highly hydrophobic surFaces (as epsilonr decreases From 0.5 to 0.1), as expected. The slip length is Functionally dependent on the aFFinity strength parameters epsilonr and sigmar: increasing logarithmically with decreasing surFace energy epsilonr (i.e., more hydrophobic), while decreasing with power law with decreasing size sigmar. The mechanism For the latter is diFFerent From the energetic case. While weak wall Forces (small epsilonr) produce hydrophobicity, larger sigmar smoothes out the surFace roughness. Both tend to increase the slip. The slip length grows rapidly with a high shear rate, as wall velocity increases three decades From 100 to 10(5) ms. We demonstrate that Fluid-solid interFaces with low epsilonr and high sigmar should be chosen to increase slip and are prime candidates For drag reduction.
Felix Hentschel - One of the best experts on this subject based on the ideXlab platform.
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corona Formation around monazite and xenotime during greenschist Facies metamorphism and deFormation
European Journal of Mineralogy, 2020Co-Authors: Felix Hentschel, Emilie Janots, Claudia A Trepmann, Valerie Magnin, Pierre LanariAbstract:Abstract. Epidote/allanite–Fluorapatite coronae around monazite and xenotime are investigated in Permian pegmatites deFormed under greenschist-Facies conditions during Alpine tectonometamorphism in the Austroalpine basement, Eastern Alps. The aim was to evaluate the replacement reactions involved in the Formation oF a corona microstructure, its age and relation to deFormation. In the corona core, monazite and xenotime single crystals show domains with diFFerent composition and age. Monazite (Mnz1) and xenotime (Xen1) dating by electron microprobe (EPM) reveals an age oF 250–287 Ma, consistent with the Permian magmatic age oF the pegmatites. These are partly replaced by secondary monazite (Mnz2) and xenotime (Xen2) compositions yielding younger Mesozoic (170–210 Ma) and Alpine (30–120 Ma) ages. The same crystallographic orientation oF the primary and secondary monazite and xenotime indicates interFace-coupled dissolution–precipitation reactions. Allanite U–Th–Pb dating by laser ablation inductively coupled mass spectrometry in the corona revealed an age oF 60±6 Ma, interpreted as the age oF corona Formation. The coronae around monazite consist oF an inner zone oF equant Fluorapatite grains surrounded by prismatic allanite, which are surrounded by epidote enriched in heavy rare earth elements (HREEs) and REE-poor epidote grains. Compared to coronae around monazite, Fluorapatite has higher REE contents and no allanite occurs in the coronae surrounding the xenotime. General reactions For monazite and xenotime breakdown can be written as Follows: Mnz1 + ( Si , Ca , Al , Fe , F ) Fluid → Mnz2 + LREE-Ap + Aln + HREE-Ep + Ep + ( Th , U ) O 2 + ( Th , U ) SiO 4 , Xen1 + ( Si , Ca , Al , Fe , F ) Fluid → Xen2 + HREE-Ap + HREE-Ep + Ep + ( Th,U ) O 2 . The amount oF replacement (judged by the relative proportions oF monazite and Fluorapatite) is low For monazite included in tourmaline but high within the mylonitic Foliation. This dependence on the degree oF replacement on the local surrounding microFabric indicates that Fluid availability along grain boundaries in the matrix and cracks controlled reaction advancement, allowing the elementary mass transFer required For corona Formation (e.g. input oF Ca, Al, Si, Fe, F). The oblate shape oF the coronae aligned within the Foliation oF the pegmatites and the deFlected Foliation around the coronae, without an outer rim oF prismatic epidote showing signs oF deFormation, indicate that the main stage oF corona Formation took place during deFormation and reactions were still ongoing aFter the main stage oF deFormation. The corona microstructure documents replacement reactions oF a single reactant into multiple distinct mineral growth zones by dissolution and precipitation processes at non-isostatic, greenschist-Facies conditions, which prevailed in the area to the north oF the DeFereggen–Antholz–Vals shear zone between the middle Cretaceous and the Oligocene. These reactions ceased beFore being completed, and REE gradients within single grains within the corona and on the thin-section scale are preserved, which suggests restricted and/or episodic transport oF REE in the Fluid phase and/or availability oF Fluid.
Carol L Shields - One of the best experts on this subject based on the ideXlab platform.
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melanoma oF the eye revealing hidden secrets one at a time
Clinics in Dermatology, 2015Co-Authors: Carol L Shields, Jane Grant M Kels, Jerry A ShieldsAbstract:Melanoma oF the eye can involve the uveal tract with iris, ciliary body, or choroid involvement or it can involve the conjunctiva, eyelid, or orbit. Uveal involvement with choroidal melanoma is the most common, Found in light complexion Caucasians with an age-adjusted incidence oF 4.3 per million persons. Early detection oF uveal melanoma is critical. The ABCDEF guide helps to diFFerentiate iris nevus From iris melanoma. The letters represent: A, age young (≤40 years); B, blood in anterior chamber; C, clock hour oF mass inFeriorly; D, diFFuse conFiguration; E, ectropion; and F, Feathery margins. The mnemonic oF TFSOM-UHHD (To Find Small Ocular Melanoma-Using HelpFul Hints Daily) helps to diFFerentiate choroidal nevus From small melanoma and represents: T, thickness over 2 mm; F, Fluid; S, symptoms; O, orange pigment; M, margin within 3 mm oF the optic disc; UH, ultrasound hollow; H, halo absent; and D, drusen absent. Patients with 3 or more oF these Factors are likely to have melanoma. These key clinical Features help to identiFy small melanoma at a time when therapy could be liFe-saving. Conjunctival melanoma usually arises From primary acquired melanosis, a Flat pigmentation that can lead to melanoma. Wide excision using no touch strategy is important to tumor control. Ocular examination is advised annually For all persons For detection oF reFractive error, cataract, glaucoma, and other conditions, but also For the detection oF asymptomatic malignancies like melanoma. One at a time, we have uncovered the secrets oF ocular melanoma and we Forge ahead with the goal to solve the riddle oF this challenging disease.