116 research outputs found
Phase equilibria for the carbon dioxide + cyclopentane + cyclohexane system at high pressures
No full textIsothermal vapor–liquid equilibrium measurements for the ternary mixture carbon dioxide + cyclopentane + cyclohexane at 353.15 K are reported. Phase equilibrium measurements were made in a high-pressure visual cell with variable volume using a static-analytical method with phases sampling by rapid online sample injectors (ROLSI) coupled to a gas chromatograph (GC) for analysis. The new measured data were modelled with the RK–PR equation of state (EoS) coupled with classical van der Waals (two-parameter conventional mixing rule, 2PCMR).Fil: Ionita, Mihaela. University Politehnica Of Bucharest; RumaniaFil: Sima, Sergiu. University Politehnica Of Bucharest; RumaniaFil: Cismondi Duarte, Martín. Universidad Nacional de Córdoba. Instituto de Investigación y Desarrollo en Ingeniería de Procesos y Química Aplicada. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación y Desarrollo en Ingeniería de Procesos y Química Aplicada; ArgentinaFil: Secuianu, Catinca. University Politehnica Of Bucharest; Rumania. Imperial College London; Reino Unid
-Butyrate Binary System
No full textVapor-liquid equilibrium data were measured for the carbon dioxide + ethyl n-butyrate (EB) binary system at high-pressures. Five isotherms are reported at (333.15, 343.15, 353.15, 363.15, and 373.15) K and pressures up to 121.75 bar. A static-analytical method with phases sampling was used. The new experimental results are compared with existing literature data and discussed. In order to provide a continuous and consistent description of the system phase behavior, unique sets of interaction parameters for different approaches with the Peng-Robinson (PR) equation of state (EoS) and classical van der Waals mixing rules were obtained. A constant kij value of -0.048 is recommended, providing an excellent description of the data reported in this work, especially for the liquid phase. Predictions are also compared with the other available literature data and discussed.Fil: Sima, Sergiu. University Politehnica of Bucharest. Faculty of
Applied Chemistry and Materials Science. Department of Inorganic Chemistry, Physical Chemistry and Electrochemistry; RumaniaFil: Cismondi Duarte, Martín. Universidad Nacional de Córdoba. Instituto de Investigación y Desarrollo en Ingeniería de Procesos y Química Aplicada. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación y Desarrollo en Ingeniería de Procesos y Química Aplicada; ArgentinaFil: Secuianu, Catinca. University Politehnica of Bucharest. Faculty of Applied Chemistry and Materials Science. Department of Inorganic Chemistry, Physical Chemistry and Electrochemistry; Rumania. Imperial College London. Department of Chemical Engineering; Reino Unid
High-pressure phase equilibrium calculations for carbon dioxide + cyclopentane binary system
No full textThe phase behavior of the carbon dioxide + cycloalkane mixtures usually receives low attention, though these systems are important for many industries, e.g. the carbon capture and storage. In this paper calculations results for the carbon dioxide + cyclopentane binary system are presented, based on SRK and PR cubic equations of state with classical van der Waals mixing rules. A single set of binary parameters for each model was proposed to predict the global phase behavior of the system in a wide range of pressure and temperature. Albeit the thermodynamic models used are simple, they are able to represent fairly well the phase behavior of the system analyzed in this paper.Fil: Sima, Sergiu. University Politehnica of Bucharest. Department of Inorganic Chemistry,
Physical Chemistry & Electrochemistry; RumaniaFil: Cruz Doblas, Julia. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnológico Bahia Blanca. Planta Piloto de Ingenieria Quimica (i). Grupo Vinculado Al Plapiqui - Investigación y Desarrollo en Tecnologia Quimica; ArgentinaFil: Cismondi Duarte, Martín. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnológico Bahia Blanca. Planta Piloto de Ingenieria Quimica (i). Grupo Vinculado Al Plapiqui - Investigación y Desarrollo en Tecnologia Quimica; ArgentinaFil: Secuianu, Catinca. University Politehnica of Bucharest. Department of Inorganic Chemistry, Physical Chemistry & Electrochemistry; Rumania. Imperial College London; Reino Unid
The effect of the naphthenic ring on the VLE of (carbon dioxide + alkane) mixtures
No full textIsothermal (vapour + liquid) equilibrium (VLE) data for the binary systems (carbon dioxide + cyclopentane) and (carbon dioxide + cyclohexane) were determined using a (static + analytical) method with phases sampling by rapid online sample injectors (ROLSI) coupled to a gas chromatograph (GC) for analysis. The VLE behaviour for these systems was also analysed based on the PR and RKPR equations of state (EoS) and different available data from the literature, both critical and subcritical. It is clearly shown how CO 2 is more soluble and miscible with normal alkanes than with the corresponding cycloalkanes. Predictions based on the general correlation of available data in wide ranges of conditions suggest the appearance of double retrograde behaviour at least for (CO 2 + cyclohexane) mixtures with very low contents of the hydrocarbon in CO 2 , being this phenomenon very much related to asymmetry of the system. The existence of this phenomenon has not been experimentally confirmed yet for these systems and should be explored.Fil: Sima, Sergiu. Politehnica University of Bucharest; RumaniaFil: Milanesio, Juan Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Planta Piloto de Ingeniería Química (I). Grupo Vinculado al Plapiqui - Investigación y Desarrollo en Tecnología Química; Argentina. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; ArgentinaFil: Ramello, Juan Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Planta Piloto de Ingeniería Química (I). Grupo Vinculado al Plapiqui - Investigación y Desarrollo en Tecnología Química; ArgentinaFil: Cismondi Duarte, Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Planta Piloto de Ingeniería Química (I). Grupo Vinculado al Plapiqui - Investigación y Desarrollo en Tecnología Química; ArgentinaFil: Secuianu, Catinca. Politehnica University of Bucharest; RumaniaFil: Feroiu, Viorel. Politehnica University of Bucharest; RumaniaFil: Geană, Dan. Politehnica University of Bucharest; Rumani
Using Quantitative Methods as Support for Audit of the Distributed Informatics Systems
No full textThis paper highlights some issues regarding how an indicators system must be developed and used in an audit process. Distributed systems are presented from de points of view of their main properties, architectures, applications, software quality characteristics and the scope of audit process in such systems. The audit process is defined in accordance to standard ISO 19011 and the main characteristics of this process are highlighted. Before using quantitative methods in audit processes, the framework in which the indicators are built must be defined. There are presented types of indicators used in audit process and classes of measurement scale. An audit process is carried out on different levels and support indicators must be in accordance to audit object. The paper presents some requirements of the indicators depending on the level of audit.Quantitative Methods, Audit Process, Distributed Informatics System
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Panel 7. Paper 7.1: Rural heritage on the World Heritage List: The case of villages with fortified churches from Romania
No full textSergiu MUSTEAŢĂ is an archaeologist working as project director at the Institute of Archaeology, Romanian Academy, Iași branch. He is the author of 7 monographs, more than 300 scientific publications, editor of over 20 books, and editor of two journals. His major academic interests are Archaeology and History of the Eastern Europe, and Cultural Heritage Preservation.Rural heritage represents the foundation of our past, which includes material and immaterial heritage. By studying rural heritage, we could better understand the past and integrate it into sustainable development of modern communities. My presentation will be focussed on the example of villages with fortified churches from Transylvania, which are the most representative rural heritage of Romania, and includes series of villages, but just seven of them were inscribed in the World Heritage List – Prejmier-Tartlau, Biertan, Valea Viilor, Calnic, Saschiz-Keisd, Darju, and Viscri. I will discuss the role and impact of public participation in various preservation and development projects. Other specific issues for these villages will be discussed too, like tourist impact on local communities. The presentation is part of our new project, which was launched in August 2017 and has the goal to identify and set up innovative models of good practices, adapted to the local cultural and social-economic specificities, for safeguarding and managing the Romanian World Heritage Sites. The project deals with multi-disciplinary and multi-perspective approach, developing partnership networks between various institutions from Romania and abroad interested in the project field and transfer of good practices on maintenance, preservation and cultural heritage management, community participation and cooperation with local public administration in order to develop National Strategy and management plans supported by realistic action plans. Only a common and integrated approach will make it possible to enrich UNESCO standards of preservation and maintain the WHS status. Keywords: Romania, World Heritage Site, Rural heritage, fortified churches, community participation
The Effect of Functional Groups on the Phase Behavior of Carbon Dioxide Binaries and Their Role in CCS
No full textIn recent years we have focused our efforts on investigating various binary mixtures containing carbon dioxide to find the best candidate for CO2 capture and, therefore, for applications in the field of CCS and CCUS technologies. Continuing this project, the present study investigates the phase behavior of three binary systems containing carbon dioxide and different oxygenated compounds. Two thermodynamic models are examined for their ability to predict the phase behavior of these systems. The selected models are the well-known Peng–Robinson (PR) equation of state and the General Equation of State (GEOS), which is a generalization for all cubic equations of state with two, three, and four parameters, coupled with classical van der Waals mixing rules (two-parameter conventional mixing rule, 2PCMR). The carbon dioxide + ethyl acetate, carbon dioxide + 1,4-dioxane, and carbon dioxide + 1,2-dimethoxyethane binary systems were analyzed based on GEOS and PR equation of state models. The modeling approach is entirely predictive. Previously, it was proved that this approach was successful for members of the same homologous series. Unique sets of binary interaction parameters for each equation of state, determined for the carbon dioxide + 2-butanol binary model system, based on k12–l12 method, were used to examine the three systems. It was shown that the models predict that CO2 solubility in the three substances increases globally in the order 1,4-dioxane, 1,2-dimethoxyethane, and ethyl acetate. CO2 solubility in 1,2-dimethoxyethane, 1.4-dioxane, and ethyl acetate reduces with increasing temperature for the same pressure, and increases with lowering temperature for the same pressure, indicating a physical dissolving process of CO2 in all three substances. However, CO2 solubility for the carbon dioxide + ether systems (1,4-dioxane, 1,2-dimethoxyethane) is better at low temperatures and pressures, and decreases with increasing pressures, leading to higher critical points for the mixtures. By contrast, the solubility of ethyl acetate in carbon dioxide is less dependent on temperatures and pressures, and the mixture has lower pressures critical points. In other words, the ethers offer better solubilization at low pressures; however, the ester has better overall miscibility in terms of lower critical pressures. Among the binary systems investigated, the 1,2-dimethoxyethane is the best solvent for CO2 absorption
Stochastic dilemmas: foundations and applications
No full textOne of the significant challenges when solving optimization problems is addressing possible inaccurate or inconsistent function evaluations. Surprisingly and interestingly, this problem is far from trivial even in one of the most basic possible settings: evaluating which of two options is better when the values of the two options are random variables (a stochastic dilemma). Problems in this space have often been studied in the statistics, operations research and computer-science communities under the name of "multi-armed bandits". While most of the previous work has focused on dealing with noise in an online setting, in this dissertation, I will focus on offline optimization where the goal is to return a reasonable solution with high probability using a finite number of samples. I will discuss a set of problem settings of increasing complexity that allow one to derive formal algorithmic bounds. I will point to and discuss interesting connections between stochastic optimization and noisy data annotation, a problem where the goal is to identify the label of an object from a series of noisy evaluations. As a first contribution, I will introduce and formally analyze a set of novel algorithms that improve the state of the art and provide new insights for solving the stochastic optimization and noisy data-annotation problems. I will then formally prove a novel result: That a widely used derivative-free optimization algorithm (the cross-entropy method) is optimizing for quantiles instead of expectation in stochastic optimization settings. I will back up the theoretical claims on the optimization side with experimental results in a set of non-trivial planning and reinforcement-learning domains. Finally, I will discuss the application of the above algorithms for solving noisy data-annotation problems in a setting involving real crowdsourcing experiments.Ph. D.Includes bibliographical referencesby Sergiu Goschi
The monograph “The operated ear disease”, the author Sergiu Vetricean
No full textDepartment of Otorhinolaryngology,
Nicolae Testemitsanu State University of Medicine and
Pharmacy Chisinau, the Republic of Moldov
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