Lennard-Jones chains

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Extending Wertheim’s perturbation theory to the solid phase of Lennard-Jones chains: Determination of the global phase diagram

Extending Wertheim’s perturbation theory to the solid phase of Lennard-Jones chains: Determination of the global phase diagram

In the mid-1980s Wertheim presented a very successful theory to study the thermodynamic properties of hard-core fluids interacting via short-range attractive 共 association 兲 forces, 1– 4 such as hydrogen bonding fluids. In this model, when the association strength becomes infinitely strong chains are formed from a fluid of associating monomers. 5 In this way it is possible to derive an equation of state for a chain of freely-jointed tangent hard segments using only thermodynamic information of the monomer reference fluid. In the simplest implementation of the theory, which is com- monly denoted as the first order thermodynamic perturbation theory 共 TPT1 兲 , the only information required in order to build an approximate equation of state for the chain fluid is the equation of state of the monomer fluid and its pair cor- relation function at contact. The equation of state 共 EOS 兲 aris- ing from TPT1 was proposed independently by Wertheim 6 and by Chapman, Jackson, and Gubbins. 7 In the early 1990s Chapman 8 showed that Wertheim’s formalism could also be applied to systems with attractive 共 dispersion 兲 forces. The work of Johnson et al. 9,10 has shown that Wertheim’s formal- ism yields a good description of the Lennard-Jones 共 LJ 兲
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Computer simulation study of the global phase behavior of linear rigid Lennard-Jones chain molecules : comparison with flexible models

Computer simulation study of the global phase behavior of linear rigid Lennard-Jones chain molecules : comparison with flexible models

When attractive interactions are incorporated in these models, gas-liquid phase behavior can also be considered. The TPT1 approach of Wertheim has been used to model the fluid-phase equilibria of hard chains with dispersion interac- tions treated at the mean-field level of van der Waals, 16 Lennard-Jones chains, 20–24 and chains of square-well 25 and Yukawa 26 segments. The approach is widely used to model the phase behavior of chainlike molecules, from n-alkanes to polymers, and their mixtures 共 see Refs. 27 and 28 for recent reviews 兲 . As mentioned above, the TPT1 does not take into account flexibility or conformational effects. Based on the fact that the equations of state of rigid and flexible hard chains are very similar in the intermediate density range, it is generally assumed that flexibility does not have a crucial effect on the fluid phase behavior. Recent works have chal- lenged this assumption, however. First, as discussed above, it is clear that if a chainlike molecule is ‘‘stiff’’ enough, liquid crystalline phases can be expected to appear, which may in- terrupt the vapor-liquid phase behavior 共 see Ref. 29 for an example of the global phase behavior of the Gay–Berne model 兲 . Even in the case of semiflexible chains in which liquid crystalline phases are not observed, Sheng et al. 1 noted a decrease in the vapor-liquid critical point of semi- flexible Lennard-Jones chains of tangent segments. Carrying out computer simulations, they predict a critical temperature 7% lower than that of a flexible chain in the limit of infinite chain length.
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Excess Thermodynamic Properties of Chainlike Mixtures. 1. Predictions from the Soft−SAFT Equation of State and Molecular Simulation

Excess Thermodynamic Properties of Chainlike Mixtures. 1. Predictions from the Soft−SAFT Equation of State and Molecular Simulation

Monte Carlo simulation and theory are used to calculate excess thermodynamic properties of binary mixtures of Lennard-Jones chains. Chainlike molecules are formed by Lennard-Jones spherical sites that are tangentially bonded. This molecular model accounts explictly for the most important microscopic features of real chainlike molecules, such as n-alkanes: repulsive and attractive forces between chemical groups and the connectivity of segments to make up the chain. A version of the statistical associating fluid theory, the so-called Soft - SAFT equation of state, is used to check the theory’s ability to predict this kind of property. Predictions from the theory are directly compared to NPT Monte Carlo simulation results obtained in the present work. The influence of segment size, dispersive energy, and chain length on excess properties is studied using simulation and theory, and results are analyzed and discussed. The equation of state is then used to predict the general trends of some excess thermodynamic properties of real n-alkane binary mixtures, such as excess volumes and heats. In particular, the temperature and chain-length dependence of these properties is studied. The Soft - SAFT theory is found to be able to correctly describe the most important features of excess thermodynamic properties of n-alkane models.
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Controlled markov chains - some stability problems

Controlled markov chains - some stability problems

Controlled Markov chains or Markov decision processes, provide a mathematical scheme for prob- lems where the outcomes contain certain ambiguity. In this section we will shortly introduce the fundamental aspects of controlled Markov Chains in the discrete context, a reference for such topic can be found in [8]. The ideas for the non-discrete context are quite similar however some mathe- matical issues appear, the interested reader can deepen in [4].

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Indiana Jones y el reino de la calavera de cristal (Steven Spielberg)

Indiana Jones y el reino de la calavera de cristal (Steven Spielberg)

Como desentrañar tamaña complejidad, el misterio de lo inabarcable, la génesis del mundo, lo absoluto, el puro y zigzagueante recorrido abstracto de la vida, sometido quizás a una cosm[r]

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Caso empresarial: Bancolombia en el Dow Jones Sustainability Índex

Caso empresarial: Bancolombia en el Dow Jones Sustainability Índex

Entienden la importancia del rol como actor social y el potencial de su actividad de servicios financieros para contribuir al desarrollo sostenible de las comunidades donde hac[r]

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Designing supply chains in emerging markets

Designing supply chains in emerging markets

There are seven items that managers must take into account to design successful supply chains. However, managers need to be aware of other five exogenous variables that affect supply chain design. According to Chopra and Meindl (2007), there are five exogenous variables that each and every manager has to bear in mind when designing supply chains. These five variables related to market conditions are: technological, macroeconomic, political, infrastructure, competitive, and logistics and facility cost. These exogenous variables must be considered when designing supply chains, due to its high impact on the supply chain design. These variables are the based for identifying the supply chain design market determinants. (See table no. 10)
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Parallel metropolis chains with cooperative adaptation

Parallel metropolis chains with cooperative adaptation

Monte Carlo methods, such as Markov chain Monte Carlo (MCMC) algorithms, have become very popular in signal pro- cessing over the last years. In this work, we introduce a novel MCMC scheme where parallel MCMC chains inter- act, adapting cooperatively the parameters of their proposal functions. Furthermore, the novel algorithm distributes the computational effort adaptively, rewarding the chains which are providing better performance and, possibly even stopping other ones. These extinct chains can be reactivated if the al- gorithm considers it necessary. Numerical simulations show the benefits of the novel scheme.
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La complejidad del polinomio de tutte y el polinomio de jones por medio de matroides

La complejidad del polinomio de tutte y el polinomio de jones por medio de matroides

En la teor´ıa de nudos, los enlaces orientados son cuerdas entrelazadas que tienen una direcci´ on espec´ıfica. En 1984 el matem´ atico neozeland´ es Vaughan Jones, descubri´ o que a estas estructuras se les pod´ıa asignar un polinomio en la variable t 1 2 , raz´ on por la cual obtuvo la medalla

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Knowledge Management in Food Supply Chains

Knowledge Management in Food Supply Chains

The 20th century left learned lessons, particularly, in the management of the tense equilibrium between the demand and supply of food. This KM refers to the increasing and optimization of the yields of the different productive systems and agro-alimentary production chains using new techniques and practices, in order to improve the farming and the processes of post-harvest, industrialization and distribution of foods. These results are due to the change of the structure of the development of diverse approaches of human knowledge, such as: Institutional changes, human capital, the appropriate practices and the adaptive invention. In this sense, KM represents a way to integrate in a single process all these different approaches. Also, from the literature review we observe that the existing KM models are pertinent to ASC, as long as a series of conditions occurs. These conditions are added in a single condition, the enterprises that integrate ASC should be structured to represent a dynamic network, in order to eliminate the barriers of learning so that knowledge flows freely among them (Hood et al, 2007). To this end, the use of the information and communication technologies is a good opportunity, through concepts and virtual enterprises.
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Modelling interstate migration in México: Static Markov Chains versus Dynamic Markov Chains with Moving Average

Modelling interstate migration in México: Static Markov Chains versus Dynamic Markov Chains with Moving Average

The objective of this article is methodological: it consists in comparing the accuracy (or inaccuracy) of Static Markov Chains v. Dynamic Markov Chains with moving averages to reproduce interstate migratory flows in Mexico. It is not intended whatsoever to propose corrections to the Mar- kovian methods used in this work, nor to propose a new method to model and project migratory flows. Our research question is much more mod- est: which Markovian method to model interstate migratory flows is more accurate (or inaccurate) for Mexico, Static Markov Chains or Dynamic Markov Chains with moving averages? Albeit simple, the question is rel- evant in methodological terms, as it allows orienting the analytical efforts of migration in Mexico to support on Markov chain’s reasoning. Even if the literature reports that DMC model better the migratory systems than SMC (Guijarro and Hierro, 2005), there no systematic comparison of both models for Mexico yet. Perhaps the main methodologic contribution of this text is the systematic way to compare the Markovian models’ accuracy.
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RESEÑA: SONIDOS DE LA DIÁSPORA. BLUES Y JAZZ EN TONI MORRISON, ALICE WALKER Y GAYL JONES. MARÍA ROCÍO COBO PIÑERO

RESEÑA: SONIDOS DE LA DIÁSPORA. BLUES Y JAZZ EN TONI MORRISON, ALICE WALKER Y GAYL JONES. MARÍA ROCÍO COBO PIÑERO

Sonidos de la Diáspora. Blues y Jazz en Toni Morrison, Alice Walker y Gayl Jones, de María Rocío Cobo Piñero (2015) representa un acercamiento poliédrico al blues, al jazz y a la literatura que surgió del contacto cultural en la diáspora africana. Su autora explora la influencia de estos dos géneros musicales en la obra literaria de Toni Morrison, Alice Walker y Gayl Jones. Ya decía Featherston que en la música se imbrican historias de la cultura donde los sonidos, la lengua y los cuerpos se encuentran (2005: 33). Los ritmos armónicos, las letras de las canciones, el baile al que estos incitan, etc. son un lenguaje en sí mismo, que Cobo Piñero conjuga inteligentemente junto con la literatura. Esto hace que el presente trabajo sea un material de gran valor para los estudios postcoloniales y dentro de estos, para los estudios diásporicos e híbridos, así como para los estudios culturales y de género. Graham Huggan se plantea en Interdisciplinary Measures (2008) que la interdisciplinaridad en los estudios postcoloniales es una práctica teórico-política innata a su campo (4). Ato Quayson distingue entre lo sinóptico (orientado hacia el concepto) y lo instrumental (aplicación pragmática) y pone de manifiesto que los estudios postcoloniales han sido altamente interdisciplinares en el
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Structural and vibrational study of PCBM

Structural and vibrational study of PCBM

into the linked chains; for example, all the C-H distances are around 1.09 Ǻ and there is not “short bonds”, as in isomer 1. The triangle (cyclopropane-like ring) formed between the (6,6) bond and the C atom of the chains has two angles of 57.87 degree, and one of 64.29 degree, while their oppose bonds were of 1.52 Ǻ and 1.62 Ǻ, respectively. This last bond length indicates that the isomer 2 has a more open structure, compared to isomer 1 (see Fig. 2).

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Automated enterprise-level models analysis & analysis chains

Automated enterprise-level models analysis & analysis chains

Recapitulating, we have that an analysis chain is the composition of many analysis functions, and both chains and functions has inputs and output parameters ontological confirm to specific metamodels. So, as we want to compose these analysis functions we find out an easier strategy to do it without be casting models in between each chain step. It is because of that we decide to use an intermediate metamodel for man- age a canonical language during entire analysis chain life cycle. So, we choose the Generic Intermediate Metamodel (GIMM) to enabling linguistic conformity between all inputs/outputs of the analysis functions even if the analysis function inputs/outputs were declared to be ontologically conforming to other metamodel. Also part of the strategy was to use GIMM instead of other generic metamodels because we have the tools that permit import metamodels, validate models conformity and export models. Consequently we realize the fact that for decoupling modeling languages using GIMM it is necessary to create some transformation T(m) functions that helps to transform a model from its ontological metamodel into GIMM and vice versa as will be explained in detail in Section 3.1. In order to illustrate this idea the Figure 4 shows in abstract two analysis functions f1 and f2 in which output of f1 and input of f2 are both ontolog- ically conforming with the same metamodel MM2. But the input of f1 is conforming to MM1 and output f2 is conforming to MM3. It means that it is possible to link f1 to f2 but it is not possible link f2 to f1.
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La adaptación cinematográfica desde una perspectiva de género: Bridget Jones´s Diary

La adaptación cinematográfica desde una perspectiva de género: Bridget Jones´s Diary

La obra de Helen Fielding, Bridget Jones´s Diary, es una de las 10 novelas que mejor reflejan la sociedad de finales del siglo XX, según un estudio llevado a cabo por el periódico The Guardian. El gran éxito de esta obra, tanto de la novela como de la película, se basa en el argumento y en técnicas narrativas que empleó Jane Austen. Dentro del género literario Chick Lit, analizaremos cómo los guionistas crearon una adaptación mediante intertextualidades que reflejan el discurso postfeminista y cuáles fueron las estrategias cinematográficas que utilizaron para la adaptación de la novela.
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Análisis y Aplicación del modelo Media Riesgo a los activos del Dow Jones

Análisis y Aplicación del modelo Media Riesgo a los activos del Dow Jones

En primer lugar, vemos como el modelo describe claramente la realidad de los mercados financieros y más concretamente del Dow Jones a lo largo del periodo considerado. Observamos como el inversor pudo obtener un rendimiento superior para los mismos niveles de riesgo durante el primer periodo, fruto de la bonanza económica que caracterizó a los mercados financieros durante los primeros años del siglo XXI. Se puede apreciar también a través de la pendiente de la Frontera Eficiente, como pequeños incrementos del riesgo le ocasionaban rendimientos considerablemente altos. Igualmente, esta situación se pone de manifiesto si comparamos las curvas de Riesgo de ambos periodos. Por último, habría que destacar que el modelo opera de forma consistente en ambos periodos, debido a que a niveles bajos de riesgo la cartera se diversifica ampliamente.
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¿Qué implica el mito de Jones y por qué aferrarse a él? Algunos problemas en las perspectivas de atribución mental

¿Qué implica el mito de Jones y por qué aferrarse a él? Algunos problemas en las perspectivas de atribución mental

La tesiS que está supuesta en la concepción de 'Loar es que se pueden adscribir propiedades objetivas, expresables en términos objetivos de la' ciencia natural desde una conce[r]

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Alcohol y cerebro adolescente : consecuencias de la ingesta de alcohol en el cerebro adolescente

Alcohol y cerebro adolescente : consecuencias de la ingesta de alcohol en el cerebro adolescente

materia gris de esta región cerebral como posible predictor de consumo abusivo futuro. (Jones y Nagel, 2019)[r]

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Understanding topological order in 1D fermion chains

Understanding topological order in 1D fermion chains

Once we have finished with the study of Clifford algebras, we will understand the role of symmetries in the periodic table of topological insulators (see figure 1 ). One of the most impo[r]

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Environmental damage estimations in industrial process chains

Environmental damage estimations in industrial process chains

Life Cycle Thinking is a way of addressing environmental issues and opportunities from a system or holistic perspective. In this way of thinking, a product or service system is evaluated with the goal of reducing potential environmental impacts over its entire life cycle, as illustrated in Figure 2.1. Life Cycle Thinking does not generally normalise the results to a functional unit, as is done as part of a Life Cycle Assessment study. The concept of Life Cycle Thinking implies the linking of individual processes to organized chains starting from a specific function. Life Cycle Thinking implies that everyone in the whole chain of a product’s life cycle, from cradle to grave, has a responsibility and a role to play, taking into account all the relevant external effects. From the exploitation of the raw material that will constitute a new product, through all the other processes of extraction, refining, manufacturing, use or consumption to its reuse, recycling or disposal, individuals must be aware of the impact that this product means to the environment and try to reduce it as much as possible. The impacts of all life cycles stages need to be considered when taking informed decisions on the production and consumption patterns, policies and management strategies (UNEP, 1999).
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