{"id":{"repo_id":"maryland","oai_identifier":"oai:drum.lib.umd.edu:1903/3815"},"canonical_url":"https://search.dev.ndltd.org/etd/maryland/oai:drum.lib.umd.edu:1903/3815","repository":{"repo_id":"maryland","name":"University of Maryland","base_url":"https://api.drum.lib.umd.edu/server/oai/request"},"display":{"title":"The Nature of Asymmetry in Fluid Criticality","abstract":"This dissertation deals with an investigation of the nature of asymmetry in fluid criticality, especially for vapor-liquid equilibra in one-component fluids and liquid-liquid equilibra in binary fluid mixtures. The conventional mixing of physical variables in scaling theory introduces an asymmetric term in diameters of coexistence curves that asymptotically varies as |ΔT|1-α, where ΔT=(T-Tc)/Tc is the relative distance of the temperature T from the critical temperature Tc. "Complete scaling" implies the presence of an additional asymmetric term proportional to |ΔT|2β in diameters which is more dominant near the critical point. To clarify the nature of vapor-liquid asymmetry, we have used the thermodynamic freedom of a proper choice for the critical entropy to simplify "complete scaling" to a form with only two independent mixing coefficients and developed a procedure to obtain these two coefficients, responsible for the two different singular sources for the asymmetry, from mean-field equations of state. By analyzing some classical equations of state we have found that the vapor-liquid asymmetry in classical fluids near the critical point can be controlled by molecular parameters, such as the degree of association and the strength of three-body interactions. By combining accurate vapor-liquid coexistence and heat-capacity data, we have obtained the unambiguous evidence for "complete scaling" from existing experimental and simulation data. A number of systems, real fluids and simulated models have been analyzed. Furthermore, we have examined the consequences of "complete scaling" when extended to liquid-liquid coexistence in binary mixtures. The procedure for extending "complete scaling" from one-component fluids to binary fluid mixtures follows rigorously the theory of isomorphism of critical phenomena. We have shown that the "singular" diameter of liquid-liquid coexistence also originates from two different sources. Finally, we have studied special phase equilibria that can only be described by including non-linear mixing of physical fields into the scaling fields. Based on scaling and isomorphism, an approach is presented to represent closed-loop coexistence curves and expressions to describe the critical lines near a double critical point (DCP) are derived. The results demonstrate the practical significance of applying scaling and isomorphism theory to the treatment of phase equilibria in chemical engineering.","abstract_html":"This dissertation deals with an investigation of the nature of asymmetry in fluid criticality, especially for vapor-liquid equilibra in one-component fluids and liquid-liquid equilibra in binary fluid mixtures. The conventional mixing of physical variables in scaling theory introduces an asymmetric term in diameters of coexistence curves that asymptotically varies as |ΔT|1-α, where ΔT=(T-Tc)/Tc is the relative distance of the temperature T from the critical temperature Tc. "Complete scaling" implies the presence of an additional asymmetric term proportional to |ΔT|2β in diameters which is more dominant near the critical point. To clarify the nature of vapor-liquid asymmetry, we have used the thermodynamic freedom of a proper choice for the critical entropy to simplify "complete scaling" to a form with only two independent mixing coefficients and developed a procedure to obtain these two coefficients, responsible for the two different singular sources for the asymmetry, from mean-field equations of state. By analyzing some classical equations of state we have found that the vapor-liquid asymmetry in classical fluids near the critical point can be controlled by molecular parameters, such as the degree of association and the strength of three-body interactions. By combining accurate vapor-liquid coexistence and heat-capacity data, we have obtained the unambiguous evidence for "complete scaling" from existing experimental and simulation data. A number of systems, real fluids and simulated models have been analyzed. Furthermore, we have examined the consequences of "complete scaling" when extended to liquid-liquid coexistence in binary mixtures. The procedure for extending "complete scaling" from one-component fluids to binary fluid mixtures follows rigorously the theory of isomorphism of critical phenomena. We have shown that the "singular" diameter of liquid-liquid coexistence also originates from two different sources. Finally, we have studied special phase equilibria that can only be described by including non-linear mixing of physical fields into the scaling fields. Based on scaling and isomorphism, an approach is presented to represent closed-loop coexistence curves and expressions to describe the critical lines near a double critical point (DCP) are derived. The results demonstrate the practical significance of applying scaling and isomorphism theory to the treatment of phase equilibria in chemical engineering.","abstract_has_math":false,"creators":["Wang, Jingtao"],"institution":null,"degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":"Chemical Engineering","school":null,"contributors":[],"advisors":["Anisimov, Mikhail A"],"committee_chairs":[],"committee_members":[],"year":2006,"date_issued":"2006-07-27","date_published":"2006-07-27","updated_at":"2026-07-24T03:02:17Z","subjects":[],"languages":["en_US"],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/1903/3815","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Anisimov, Mikhail A"]},{"key":"dc:contributor.department","label":"Department","values":["Chemical Engineering"]},{"key":"dc:creator","label":"Author","values":["Wang, Jingtao"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2006-09-12T05:49:23Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2006-09-12T05:49:23Z"]},{"key":"dc:date.issued","label":"Date","values":["2006-07-27"]},{"key":"dc:type","label":"Dc Type","values":["Dissertation"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language.iso","label":"Language (ISO)","values":["en_US"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["http://hdl.handle.net/1903/3815"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["This dissertation deals with an investigation of the nature of asymmetry in fluid criticality, especially for vapor-liquid equilibra in one-component fluids and liquid-liquid equilibra in binary fluid mixtures. The conventional mixing of physical variables in scaling theory introduces an asymmetric term in diameters of coexistence curves that asymptotically varies as |ΔT|1-α, where ΔT=(T-Tc)/Tc is the relative distance of the temperature T from the critical temperature Tc. "Complete scaling" implies the presence of an additional asymmetric term proportional to |ΔT|2β in diameters which is more dominant near the critical point. To clarify the nature of vapor-liquid asymmetry, we have used the thermodynamic freedom of a proper choice for the critical entropy to simplify "complete scaling" to a form with only two independent mixing coefficients and developed a procedure to obtain these two coefficients, responsible for the two different singular sources for the asymmetry, from mean-field equations of state. By analyzing some classical equations of state we have found that the vapor-liquid asymmetry in classical fluids near the critical point can be controlled by molecular parameters, such as the degree of association and the strength of three-body interactions. By combining accurate vapor-liquid coexistence and heat-capacity data, we have obtained the unambiguous evidence for "complete scaling" from existing experimental and simulation data. A number of systems, real fluids and simulated models have been analyzed. Furthermore, we have examined the consequences of "complete scaling" when extended to liquid-liquid coexistence in binary mixtures. The procedure for extending "complete scaling" from one-component fluids to binary fluid mixtures follows rigorously the theory of isomorphism of critical phenomena. We have shown that the "singular" diameter of liquid-liquid coexistence also originates from two different sources. Finally, we have studied special phase equilibria that can only be described by including non-linear mixing of physical fields into the scaling fields. Based on scaling and isomorphism, an approach is presented to represent closed-loop coexistence curves and expressions to describe the critical lines near a double critical point (DCP) are derived. The results demonstrate the practical significance of applying scaling and isomorphism theory to the treatment of phase equilibria in chemical engineering."]},{"key":"dc:format.mimetype","label":"Dc Format Mimetype","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["The Nature of Asymmetry in Fluid Criticality"]}]}],"canonical_facts":{"dc:contributor.advisor":["Anisimov, Mikhail A"],"dc:contributor.department":["Chemical Engineering"],"dc:creator":["Wang, Jingtao"],"dc:date.accessioned":["2006-09-12T05:49:23Z"],"dc:date.available":["2006-09-12T05:49:23Z"],"dc:date.issued":["2006-07-27"],"dc:description.abstract":["This dissertation deals with an investigation of the nature of asymmetry in fluid criticality, especially for vapor-liquid equilibra in one-component fluids and liquid-liquid equilibra in binary fluid mixtures. The conventional mixing of physical variables in scaling theory introduces an asymmetric term in diameters of coexistence curves that asymptotically varies as |ΔT|1-α, where ΔT=(T-Tc)/Tc is the relative distance of the temperature T from the critical temperature Tc. "Complete scaling" implies the presence of an additional asymmetric term proportional to |ΔT|2β in diameters which is more dominant near the critical point. To clarify the nature of vapor-liquid asymmetry, we have used the thermodynamic freedom of a proper choice for the critical entropy to simplify "complete scaling" to a form with only two independent mixing coefficients and developed a procedure to obtain these two coefficients, responsible for the two different singular sources for the asymmetry, from mean-field equations of state. By analyzing some classical equations of state we have found that the vapor-liquid asymmetry in classical fluids near the critical point can be controlled by molecular parameters, such as the degree of association and the strength of three-body interactions. By combining accurate vapor-liquid coexistence and heat-capacity data, we have obtained the unambiguous evidence for "complete scaling" from existing experimental and simulation data. A number of systems, real fluids and simulated models have been analyzed. Furthermore, we have examined the consequences of "complete scaling" when extended to liquid-liquid coexistence in binary mixtures. The procedure for extending "complete scaling" from one-component fluids to binary fluid mixtures follows rigorously the theory of isomorphism of critical phenomena. We have shown that the "singular" diameter of liquid-liquid coexistence also originates from two different sources. Finally, we have studied special phase equilibria that can only be described by including non-linear mixing of physical fields into the scaling fields. Based on scaling and isomorphism, an approach is presented to represent closed-loop coexistence curves and expressions to describe the critical lines near a double critical point (DCP) are derived. The results demonstrate the practical significance of applying scaling and isomorphism theory to the treatment of phase equilibria in chemical engineering."],"dc:format.mimetype":["application/pdf"],"dc:identifier.uri":["http://hdl.handle.net/1903/3815"],"dc:language.iso":["en_US"],"dc:title":["The Nature of Asymmetry in Fluid Criticality"],"dc:type":["Dissertation"]},"updated_at":"2026-07-24T03:02:17Z"}