Sample records for extreme correlated equilibria

  1. Learning efficient correlated equilibria

    KAUST Repository

    Borowski, Holly P.


    The majority of distributed learning literature focuses on convergence to Nash equilibria. Correlated equilibria, on the other hand, can often characterize more efficient collective behavior than even the best Nash equilibrium. However, there are no existing distributed learning algorithms that converge to specific correlated equilibria. In this paper, we provide one such algorithm which guarantees that the agents\\' collective joint strategy will constitute an efficient correlated equilibrium with high probability. The key to attaining efficient correlated behavior through distributed learning involves incorporating a common random signal into the learning environment.

  2. Exogenous empirical-evidence equilibria in perfect-monitoring repeated games yield correlated equilibria

    KAUST Repository

    Dudebout, Nicolas


    This paper proves that exogenous empirical-evidence equilibria (xEEEs) in perfect-monitoring repeated games induce correlated equilibria of the associated one-shot game. An empirical-evidence equilibrium (EEE) is a solution concept for stochastic games. At equilibrium, agents\\' strategies are optimal with respect to models of their opponents. These models satisfy a consistency condition with respect to the actual behavior of the opponents. As such, EEEs replace the full-rationality requirement of Nash equilibria by a consistency-based bounded-rationality one. In this paper, the framework of empirical evidence is summarized, with an emphasis on perfect-monitoring repeated games. A less constraining notion of consistency is introduced. The fact that an xEEE in a perfect-monitoring repeated game induces a correlated equilibrium on the underlying one-shot game is proven. This result and the new notion of consistency are illustrated on the hawk-dove game. Finally, a method to build specific correlated equilibria from xEEEs is derived.

  3. Correlated equilibria in homogenous good Bertrand competition

    DEFF Research Database (Denmark)

    Jann, Ole; Schottmüller, Christoph


    We show that there is a unique correlated equilibrium, identical to the unique Nash equilibrium, in the classic Bertrand oligopoly model with homogenous goods and identical marginal costs. This provides a theoretical underpinning for the so-called "Bertrand paradox'' as well as its most general f...... formulation to date. Our proof generalizes to asymmetric marginal costs and arbitrarily many players in the following way: The market price cannot be higher than the second lowest marginal cost in any correlated equilibrium....

  4. Protein oligomerization equilibria and kinetics investigated by fluorescence correlation spectroscopy: a mathematical treatment. (United States)

    Kanno, David M; Levitus, Marcia


    Fluorescence correlation spectroscopy (FCS) is a technique that is increasingly being used to investigate protein oligomerization equilibria and dynamics. Each individual FCS decay is characterized by its amplitude and a characteristic diffusion time, both of which are sensitive to the degree of dissociation of the protein. Here, we provide a mathematical treatment that relates these observables with the parameters of interest: the equilibrium constants of the different protein dissociation steps and their corresponding dissociation and association kinetic rate constants. We focused on the two most common types of protein homooligomers (dimers and tetramers) and on the experimental variables relevant for the design of the experiment (protein concentration, fractional concentration of labeled protein). The analysis of the theoretical expectations for proteins with different dissociation constants is a key aspect of experiment design and data analysis and cannot be performed without a physically accurate treatment of the system. In particular, we show that the analysis of FCS data using some commonly used empirical models may result in a serious misinterpretation of the experimental results.

  5. Correlation of Vapor-Liquid Equilibria for Commonly Used Binary Systems in Supercritical Fluid Extraction Processes

    Directory of Open Access Journals (Sweden)

    Saeid Atashrouz


    Full Text Available In this paper, a comprehensive mathematical model is developed based on the Feed-ForwardBack Propagation Artificial Neural Network (FFBP-ANN. The model is employed for thecalculation of Vapor Liquid Equilibria (VLE of four CO2-containing binary mixtures. Themixtures include CO2 - Tertpentanol was investigated at the temperature range from 313.14 to343.15 K. The following mixtures including CO2 - Isobutanol at 313.2 to 353.2 K, CO2 - methylacetate at 308.15 to 328.15 K and CO2 - diisopropyl ether at 265.15 to 333.15 K wereinvestigated as well. The related experimental data of open literature have been used to constructthe model. The results confirm that there is a reasonable conformity between the predicted valuesand the experimental data. Additionally, the ability of the ANN model is examined by comparison with the conventional thermodynamic models and ANN model predicted VLE datawith more accuracy.

  6. Determining extreme parameter correlation in ground water models

    DEFF Research Database (Denmark)

    Hill, Mary Cole; Østerby, Ole


    In ground water flow system models with hydraulic-head observations but without significant imposed or observed flows, extreme parameter correlation generally exists. As a result, hydraulic conductivity and recharge parameters cannot be uniquely estimated. In complicated problems, such correlation...

  7. Reliable Correlation for Liquid-Liquid Equilibria Outside the Critical Region

    DEFF Research Database (Denmark)

    Ruszczynski, Lukasz; Zubov, Alexandr; O’Connell, John P.


    A simple model for binary liquid–liquid equilibrium data correlation is explored. The model describes liquid–liquid equilibrium in terms of Henry’s law and unsymmetrically normalized activity coefficients in each phase. A procedure for parameter estimation including an approach to initial guesses...... the available data, this number can be extended in a systematic fashion. We compare results of correlation to results obtained with a four-parameter nonrandom two-liquid (NRTL) equation and COSMO-SAC. In general, the new model does nearly as well as NRTL. Advantages of the presented model are a simple form...

  8. Liquid-liquid equilibria for glycols plus hydrocarbons: Data and correlation

    DEFF Research Database (Denmark)

    Derawi, Samer; Kontogeorgis, Georgios; Stenby, Erling Halfdan


    Liquid-liquid equilibrium data for seven binary glycol-hydrocarbon systems have been measured in the temperature range 32 degreesC to 80 degreesC and at the pressure 1 bar. The measured systems are monoethylene glycol (MEG) + heptane, methyleyclohexane (MCH) + hexane, propylene glycol (PG......) + heptane, diethylene glycol (DEG) + heptane, triethylene glycol (TEG) + heptane, and tetraethylene glycol (TETRA) + heptane. The data obtained were correlated with the NRTL model and two different versions of the UNIQUAC equation. The NRTL model and one of the UNIQUAC equations (UQ 4) have a linear...

  9. Extreme eigenvalues of sample covariance and correlation matrices

    DEFF Research Database (Denmark)

    Heiny, Johannes


    This thesis is concerned with asymptotic properties of the eigenvalues of high-dimensional sample covariance and correlation matrices under an infinite fourth moment of the entries. In the first part, we study the joint distributional convergence of the largest eigenvalues of the sample covariance...... that the extreme eigenvalues are essentially determined by the extreme order statistics from an array of iid random variables. The asymptotic behavior of the extreme eigenvalues is then derived routinely from classical extreme value theory. The resulting approximations are strikingly simple considering the high...... dimension of the problem at hand. We develop a theory for the point process of the normalized eigenvalues of the sample covariance matrix in the case where rows and columns of the data are linearly dependent. Based on the weak convergence of this point process we derive the limit laws of various functionals...

  10. Generalised extreme value statistics and sum of correlated variables


    Bertin, Eric; Clusel, Maxime


    To appear in J.Phys.A; We show that generalised extreme value statistics -the statistics of the k-th largest value among a large set of random variables- can be mapped onto a problem of random sums. This allows us to identify classes of non-identical and (generally) correlated random variables with a sum distributed according to one of the three (k-dependent) asymptotic distributions of extreme value statistics, namely the Gumbel, Frechet and Weibull distributions. These classes, as well as t...

  11. Extreme eigenvalues of sample covariance and correlation matrices

    DEFF Research Database (Denmark)

    Heiny, Johannes

    This thesis is concerned with asymptotic properties of the eigenvalues of high-dimensional sample covariance and correlation matrices under an infinite fourth moment of the entries. In the first part, we study the joint distributional convergence of the largest eigenvalues of the sample covariance...... eigenvalues are essentially determined by the extreme order statistics from an array of iid random variables. The asymptotic behavior of the extreme eigenvalues is then derived routinely from classical extreme value theory. The resulting approximations are strikingly simple considering the high dimension...... of the problem at hand. We develop a theory for the point process of the normalized eigenvalues of the sample covariance matrix in the case where rows and columns of the data are linearly dependent. Based on the weak convergence of this point process we derive the limit laws of various functionals...

  12. Multifractal Geophysical Extremes: Nonstationarity and Long Range Correlations (United States)

    Tchiguirinskaia, I.; Schertzer, D.; Lovejoy, S.


    Throughout the world, extremes in environmental sciences are of prime importance. They are key variables not only for risk assessments and engineering designs (e.g. of dams and bridges), but also for resource management (e.g. water and energy) and for land use. A better understanding of them is more and more indispensable in settling the debate on their possible climatological evolution. Whereas it took decades before a uniform technique for estimating flow frequencies within a stationary framework, it is often claimed that « stationarity is dead ! ». The fact that geophysical and environmental fields are variable over a wider range of scales than previously thought require to go beyond the limits of the (classical) Extreme Value Theory (EVT). Indeed, long-range correlations are beyond the scope of the classical EVT theory. We show that multifractal concepts and techniques are particularly appealing because they can effectively deal with a cascade of interactions concentrating for instance energy, liquid water, etc. into smaller and smaller space-time domains. Furthermore, a general outcome of these cascade processes -which surprisingly was realized only rather recently- is that rather independently of their details they yield probability distributions with power-law fall-offs, often called (asymptotic) Pareto or Zipf laws. We discuss the corresponding probability distributions of their maxima and its relationship with the Frechet law. We use these multifractal techniques to investigate the possibility of using very short or incomplete data records for reliable statistical predictions of the extremes. In particular we assess the multifractal parameter uncertainty with the help of long synthetic multifractal series and their sub-samples, in particular to obtain an approximation of confidence intervals that would be particularly important for the predictions of multifractal extremes. We finally illustrate the efficiency of this approach with its application to

  13. Extreme Sport/Adventure Activity Correlates in Gynecologic Cancer Survivors. (United States)

    Crawford, Jennifer J; Vallance, Jeff K; Holt, Nicholas L; Courneya, Kerry S


    We examined the demographic, medical and behavioral correlates of participation and interest in extreme sport/adventure activities (ESAA) in gynecologic cancer survivors. A random sample of 621 gynecologic cancer survivors in Alberta, Canada, completed a mailed self-report questionnaire assessing medical, demographic, and behavioral variables and participation and interest in ESAA. Multivariate analyses revealed that gynecologic cancer survivors were more likely to participate in ESAA if they met aerobic exercise guidelines (OR=1.75 [95%CI:1.02-2.99]), had better general health (OR=1.71 [95%CI: 1.01-2.90]), had cervical or ovarian cancer (OR=1.95 [95%CI:0.97-3.93]), were employed (OR=1.71 [95%CI:0.95-3.08]), and were of healthy weight (OR=1.58 [95%CI:0.93-2.68]). Moreover, gynecologic cancer survivors were more likely to be interested in trying an ESAA if they had cervical or ovarian cancer (OR=1.76 [95%CI:0.94-3.27]) and were meeting the strength exercise guidelines (OR=1.68 [95%CI:0.95-2.98]). Medical, demographic, and behavioral variables correlate with participation and interest in ESAA in gynecologic cancer survivors. The pattern of correlates suggests that gynecologic cancer survivors are more likely to participate in ESSA if they have the physical capability and financial resources. Interventions to promote ESAA in gynecologic cancer survivors need to address these 2 key barriers.

  14. Self-reported upper extremity health status correlates with depression. (United States)

    Ring, David; Kadzielski, John; Fabian, Lauren; Zurakowski, David; Malhotra, Leah R; Jupiter, Jesse B


    The Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire is the most widely used upper extremity-specific health-status measure. The DASH score often demonstrates greater variability than would be expected on the basis of objective pathology. This variability may be related to psychosocial factors. The purpose of the present study was to investigate the correlation between the DASH score and psychological factors for specific diagnoses with relatively limited variation in objective pathology. Two hundred and thirty-five patients with a single, common, discrete hand problem known to have limited variations in objective pathology completed the DASH questionnaire, the Eysenck Personality Questionnaire-Revised (EPQ-R) to assess neuroticism, the Center for Epidemiologic Studies-Depression (CES-D) scale to quantify depressive symptoms, and the Pain Anxiety Symptoms Scale (PASS). Forty-five patients had carpal tunnel syndrome, forty-four had de Quervain tenosynovitis, forty-eight had lateral elbow pain, and seventy-one had a single trigger finger. In addition, twenty-seven patients were evaluated six weeks after a nonoperatively treated fracture of the distal part of the radius. Relationships between psychosocial factors and the DASH score were determined. A significant positive correlation between the DASH score and depression was noted for all diagnoses (r = 0.38 to 0.52; p Quervain tendinitis, r = 0.46; lateral elbow pain, r = 0.42; and trigger finger, r = 0.24) (p < 0.05 for all). The DASH score was not correlated with neuroticism for any diagnosis. There was a highly significant effect of depression (as measured with the CES-D score) on the DASH score for all diagnoses. Both the CES-D score (F = 62.68, p < 0.0001) and gender (F = 11.36, p < 0.001) were independent predictors of the DASH score. Self-reported upper extremity-specific health status as measured with the DASH score correlates with depression and pain anxiety but not neuroticism. These data

  15. Measurement and correlation of vapor-liquid equilibria for a binary system containing 1-butyl-3-methylimidazolium tridecafluorohexyl sulfonate and carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Soon Kang; Park, Yoon Kook [Hongik University, Sejong (Korea, Republic of)


    Using a high-pressure variable-volume view cell, the vapor-liquid equilibria of the binary system CO{sub 2} and 1-butyl-3-methylimidazolium tridecafluorohexylsulfonate ([BMIM][TDfO]) were determined. The CO{sub 2} mole fraction ranged from 0.104 to 0.952 over a temperature range of 298.2-323.2 K. Both the Peng-Robinson and Soave-Redlich- Kwong equations of state were applied with two different mixing rules to correlate with the experimentally obtained results. Increasing the alkyl chain length in perfluorinated sulfonate anion mother structure from methyl to hexyl markedly increased the CO{sub 2} solubility. To investigate the effect of the number of fluorine atoms in the anion on the phase behavior of imidazolium-based ionic liquid, these experimental results were then compared with those reported in previous experimental studies of 1-alkyl-3-methylimidazolium cations-including ionic liquid+CO{sub 2} binary system.

  16. Extreme obesity: sociodemographic, familial and behavioural correlates in The Netherlands

    NARCIS (Netherlands)

    Merkus, M. P.; Mathus-Vliegen, L. M.; Broekhoff, C.; Heijnen, A. M.


    To investigate the relationship between sociodemographic, behavioural, and family characteristics and the body mass index (BMI) (weight (kg)/height (m2)) of extremely obese people. Self reported sociodemographic, behavioural, and familial characteristics and weight and height were obtained by postal

  17. Extremal quantum correlations: Experimental study with two-qubit states

    Energy Technology Data Exchange (ETDEWEB)

    Chiuri, A.; Mataloni, P. [Dipartimento di Fisica, Sapienza Universita di Roma, Piazzale Aldo Moro 5, I-00185 Roma (Italy); Istituto Nazionale di Ottica (INO-CNR), L.go E. Fermi 6, I-50125 Firenze (Italy); Vallone, G. [Dipartimento di Fisica, Sapienza Universita di Roma, Piazzale Aldo Moro 5, I-00185 Roma (Italy); Museo Storico della Fisica e Centro Studi e Ricerche Enrico Fermi, Via Panisperna 89/A, Compendio del Viminale, I-00184 Roma (Italy); Paternostro, M. [Centre for Theoretical Atomic, Molecular, and Optical Physics, School of Mathematics and Physics, Queen' s University, Belfast BT7 1NN (United Kingdom)


    We explore experimentally the space of two-qubit quantum-correlated mixed states, including frontier states as defined by the use of quantum discord and von Neumann entropy. Our experimental setup is flexible enough to allow for high-quality generation of a vast variety of states. We address quantitatively the relation between quantum discord and a recently suggested alternative measure of quantum correlations.

  18. Sources of correlation between experts: Empirical results from two extremes

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, M.A.; Booker, J.M.


    Through two studies, this report seeks to identify the sources of correlation, or dependence, between experts' estimates. Expert estimates are relied upon as sources of data whenever experimental data is lacking, such as in risk analyses and reliability assessments. Correlation between experts is a problem in the elicitation and subsequent use of subjective estimates. Until now, there have been no data confirming sources of correlation, although the experts' background is commonly speculated to be one. Two different populations of experts were administered questions in their areas of expertise. Data on their professional backgrounds and means of solving the questions were elicited using techniques from educational psychology and ethnography. The results from both studies indicate that the way in which an expert solves the problem is the major source of correlation. The experts' background can not be shown to be an important source of correlation nor to influence his choice of method for problem solution. From these results, some recommendations are given for the elicitation and use of expert opinion.

  19. Postures of upper extremity correlated with carpal tunnel syndrome (CTS). (United States)

    Chiang, Chia-Liang; Liao, Chu-Yung; Kuo, Hsien-Wen


    Non-medical hospital staff members are in frequent contact with patients and therefore are required to perform a wide variety of repetitive and high-frequency activities. The objective of this study was to assess the relationships between upper extremity activity and carpal tunnel syndrome (CTS) among non-medical hospital staff members. Carpal tunnel syndrome in 144 non-medical hospital staff members was diagnosed using the Nordic Musculoskeletal Questionnaire (NMQ), a physician's diagnosis, physical examination (Tinel's signs and Phalen test) and a nerve conduction velocity (NCV) test. In addition, an ergonomic assessment was performed and a video camera was used to record the physical activities at work. The prevalence rate of CTS was highest for the NMQ (51.9%), followed by physician's diagnosis (49.5% for the right hand, 29.9% for the left hand), physical examination (54.7%), and nerve conduction test (motor nerve 27.5% and 25%, sensory nerve 21.7% and 15%, for right and left hands, respectively). Based on logistic regression models for the NMQ and physician's diagnoses, there was a dose-dependently higher risk of CTS with the upper extremity index among participants, but this was non-significant based on the physical examination and nerve conduction tests. Nerve conduction velocity is the gold standard in diagnosis of CTS, but use of NMQ and physician's diagnosis may overestimate the incidence of CTS in workers who have been engaging in repetitive stress activities for a relatively short time. Int J Occup Med Environ Health 2017;30(2):281-290.

  20. Extreme eigenvalues of sample covariance and correlation matrices

    DEFF Research Database (Denmark)

    Heiny, Johannes

    of the problem at hand. We develop a theory for the point process of the normalized eigenvalues of the sample covariance matrix in the case where rows and columns of the data are linearly dependent. Based on the weak convergence of this point process we derive the limit laws of various functionals......This thesis is concerned with asymptotic properties of the eigenvalues of high-dimensional sample covariance and correlation matrices under an infinite fourth moment of the entries. In the first part, we study the joint distributional convergence of the largest eigenvalues of the sample covariance...... matrix of a p-dimensional heavy-tailed time series when p converges to infinity together with the sample size n. We generalize the growth rates of p existing in the literature. Assuming a regular variation condition with tail index

  1. Extreme eigenvalues of sample covariance and correlation matrices

    DEFF Research Database (Denmark)

    Heiny, Johannes


    dimension of the problem at hand. We develop a theory for the point process of the normalized eigenvalues of the sample covariance matrix in the case where rows and columns of the data are linearly dependent. Based on the weak convergence of this point process we derive the limit laws of various functionals......This thesis is concerned with asymptotic properties of the eigenvalues of high-dimensional sample covariance and correlation matrices under an infinite fourth moment of the entries. In the first part, we study the joint distributional convergence of the largest eigenvalues of the sample covariance...... matrix of a $p$-dimensional heavy-tailed time series when $p$ converges to infinity together with the sample size $n$. We generalize the growth rates of $p$ existing in the literature. Assuming a regular variation condition with tail index $\\alpha

  2. Institutions, Equilibria and Efficiency

    DEFF Research Database (Denmark)

    Competition and efficiency is at the core of economic theory. This volume collects papers of leading scholars, which extend the conventional general equilibrium model in important ways. Efficiency and price regulation are studied when markets are incomplete and existence of equilibria...

  3. Resurrecting Equilibria Through Cycles

    DEFF Research Database (Denmark)

    Barnett, Richard C.; Bhattacharya, Joydeep; Bunzel, Helle

    In an overlapping generations model, momentary equilibria are defined as points that lie on the intergenerational offer curve, i.e., they satisfy agents' optimality conditions and market clearing at any date. However, some dynamic sequences commencing from such points may not be considered valid ...

  4. Institutions, Equilibria and Efficiency

    DEFF Research Database (Denmark)

    Competition and efficiency is at the core of economic theory. This volume collects papers of leading scholars, which extend the conventional general equilibrium model in important ways. Efficiency and price regulation are studied when markets are incomplete and existence of equilibria in such set......Competition and efficiency is at the core of economic theory. This volume collects papers of leading scholars, which extend the conventional general equilibrium model in important ways. Efficiency and price regulation are studied when markets are incomplete and existence of equilibria...... in such settings is proven under very general preference assumptions. The model is extended to include geographical location choice, a commodity space incorporating manufacturing imprecision and preferences for club-membership, schools and firms. Inefficiencies arising from household externalities or group...... in OLG, learning in OLG and in games, optimal pricing of derivative securities, the impact of heterogeneity...

  5. Effect of extreme data loss on long-range correlated and anti-correlated signals quantified by detrended fluctuation analysis

    CERN Document Server

    Ma, Qianli D Y; Bernaola-Galván, Pedro; Yoneyama, Mitsuru; Ivanov, Plamen Ch


    We investigate how extreme loss of data affects the scaling behavior of long-range power-law correlated and anti-correlated signals applying the DFA method. We introduce a segmentation approach to generate surrogate signals by randomly removing data segments from stationary signals with different types of correlations. These surrogate signals are characterized by: (i) the DFA scaling exponent $\\alpha$ of the original correlated signal, (ii) the percentage $p$ of the data removed, (iii) the average length $\\mu$ of the removed (or remaining) data segments, and (iv) the functional form of the distribution of the length of the removed (or remaining) data segments. We find that the {\\it global} scaling exponent of positively correlated signals remains practically unchanged even for extreme data loss of up to 90%. In contrast, the global scaling of anti-correlated signals changes to uncorrelated behavior even when a very small fraction of the data is lost. These observations are confirmed on the examples of human g...

  6. Model of geophysical fields representation in problems of complex correlation-extreme navigation

    Directory of Open Access Journals (Sweden)

    Volodymyr KHARCHENKO


    Full Text Available A model of the optimal representation of spatial data for the task of complex correlation-extreme navigation is developed based on the criterion of minimum deviation of the correlation functions of the original and the resulting fields. Calculations are presented for one-dimensional case using the approximation of the correlation function by Fourier series. It is shown that in the presence of different geophysical map data fields their representation is possible by single template with optimal sampling without distorting the form of the correlation functions.

  7. The use of copula functions for predictive analysis of correlations between extreme storm tides (United States)

    Domino, Krzysztof; Błachowicz, Tomasz; Ciupak, Maurycy


    In this paper we present a method used in quantitative description of weakly predictable hydrological, extreme events at inland sea. Investigations for correlations between variations of individual measuring points, employing combined statistical methods, were carried out. As a main tool for this analysis we used a two-dimensional copula function sensitive for correlated extreme effects. Additionally, a new proposed methodology, based on Detrended Fluctuations Analysis (DFA) and Anomalous Diffusion (AD), was used for the prediction of negative and positive auto-correlations and associated optimum choice of copula functions. As a practical example we analysed maximum storm tides data recorded at five spatially separated places at the Baltic Sea. For the analysis we used Gumbel, Clayton, and Frank copula functions and introduced the reversed Clayton copula. The application of our research model is associated with modelling the risk of high storm tides and possible storm flooding.

  8. Extreme Events in Space Weather: Long-Range Correlations and Clustering (United States)

    Sharma, S.; Veeramani, T.


    Space weather is driven by the solar wind and many extreme geomagnetic events such as space storms and substorms are potential natural hazards. The statistical studies of these vents are complicated because of the turbulent nature of their driver, the solar wind. On the other hand archived data of geospace storms and substorms for very long periods are available and are amenable to detailed analysis using many techniques. For example, a database of substorms consisting of more than million events have been compiled for this study of the inherent statistical characteristics of extreme events in geospace. The auto- correlation and mutual-information functions are used to obtain the scaling exponents and they show the presence of long-term correlations and clustering. The scaling is represented by two exponents, the break arising due mainly to the turbulent nature of the solar wind driving the events. The auto-correlation functions show stronger long-term correlation than the mutual information functions, which represent correlations of all orders. The return intervals for varying thresholds show long-range correlations with decreasing strength for higher thresholds, similar to the case of multifractal systems. The techniques of detrended fluctuation analysis are used to further study of the long-range correlations and clustering of geospace events.

  9. Lower Extremity Strength Is Correlated with Walking Function After Incomplete SCI. (United States)

    DiPiro, Nicole D; Holthaus, Katy D; Morgan, Patrick J; Embry, Aaron E; Perry, Lindsay A; Bowden, Mark G; Gregory, Chris M


    Lower extremity strength has been reported to relate to walking ability, however, the relationship between voluntary lower extremity muscle function as measured by isokinetic dynamometry and walking have not been thoroughly examined in individuals with incomplete spinal cord injury (iSCI). To determine the extent to which measures of maximal voluntary isometric contraction (MVIC) and rate of torque development (RTD) in the knee extensor (KE) and plantar flexor (PF) muscle groups correlate with self-selected overground walking speed and spatiotemporal characteristics of walking. Twenty-two subjects with chronic (>6 months) iSCI participated in a cross-sectional study. Values for MVIC and RTD in the KE and PF muscle groups were determined by isokinetic dynamometry. Walking speed and spatiotemporal characteristics of walking were measured during overground walking. MVIC in the KE and PF muscle groups correlated significantly with walking speed. RTD was significantly correlated with walking speed in both muscle groups, the more-involved PF muscle group showing the strongest correlation with walking speed (r = 0.728). RTD in the KE and PF muscle groups of the more-involved limb was significantly correlated with single support time of the more-involved limb. These data demonstrate that lower extremity strength is associated with walking ability after iSCI. Correlations for the muscle groups of the move-involved side were stronger compared to the less-involved limb. In addition, PF function is highlighted as a potential limiting factor to walking speed along with the importance of RTD.

  10. An Examination of Lower Extremity Function and its Correlates in Older African American and White Men. (United States)

    Clay, Olivio J; Thorpe, Roland J; Wilkinson, Larrell L; Plaisance, Eric P; Crowe, Michael; Sawyer, Patricia; Brown, Cynthia J


    Maintaining functional status and reducing/eliminating health disparities in late life are key priorities. Older African Americans have been found to have worse lower extremity functioning than Whites, but little is known about potential differences in correlates between African American and White men. The goal of this investigation was to examine measures that could explain this racial difference and to identify race-specific correlates of lower extremity function. Data were analyzed for a sample of community-dwelling men. Linear regression models examined demographics, medical conditions, health behaviors, and perceived discrimination and mental health as correlates of an objective measure of lower extremity function, the Short Physical Performance Battery (SPPB). Scores on the SPPB have a potential range of 0 to 12 with higher scores corresponding to better functioning. The mean age of all men was 74.9 years (SD=6.5), and the sample was 50% African American and 53% rural. African American men had scores on the SPPB that were significantly lower than White men after adjusting for age, rural residence, marital status, education, and income difficulty (Pplanning targeted interventions to help reduce disparities.

  11. Adsorption analysis equilibria and kinetics

    CERN Document Server

    Do, Duong D


    This book covers topics of equilibria and kinetics of adsorption in porous media. Fundamental equilibria and kinetics are dealt with for homogeneous as well as heterogeneous particles. Five chapters of the book deal with equilibria and eight chapters deal with kinetics. Single component as well as multicomponent systems are discussed. In kinetics analysis, we deal with the various mass transport processes and their interactions inside a porous particle. Conventional approaches as well as the new approach using Maxwell-Stefan equations are presented. Various methods to measure diffusivity, such

  12. Correlation between Intrinsic Patellofemoral Pain Syndrome in Young Adults and Lower Extremity Biomechanics (United States)

    Kwon, Ohjeoung; Yun, Mijung; Lee, Wanhee


    [Purpose] The purpose of this study was to evaluate the correlation between intrinsic patellofemoral pain syndrome (PFPS) in young adults and lower extremity biomechanics. [Subjects] This experiment was carried out with sixty (24 men and 32 women), who are normal university students as subjects. [Methods] All subjects underwent 3 clinical evaluations. For distinguishing the intrinsic PFPS from controls, we used the Modified Functional Index Questionnaire (MFIQ), Clarke’s test and the Eccentric step test. Based on the results of the tests, subjects who were classified as positive for 2 more tests were allocated to the bilateral or unilateral intrinsic PFPS group (n=14), and the others were allocated to the control group (n=42). These two groups were tested for hamstring tightness, foot overpronation, and static Q-angle and dynamic Q-angle. These are the four lower extremity biomechanic, cited as risk factors of patellofemoral pain syndrome. [Results] The over pronation, static Q-angle and the dynamic Q-angle were not significantly different between the two groups. However, the hamstring tightness of the PFPS group was significantly greater than that of the controls. [Conclusion] We examined individuals for intrinsic patellofemoral pain syndrome in young adults and lower extremity biomechanics. We found a strong correlation between intrinsic PFPS and hamstring tightness. PMID:25140074

  13. Toroidal equilibria in spherical coordinates


    Tsui, K. H.


    The standard Grad-Shafranov equation for axisymmetric toroidal plasma equilibrium is customary expressed in cylindrical coordinates with toroidal contours, and through which benchmark equilibria are solved. An alternative approach to cast the Grad-Shafranov equation in spherical coordinates is presented. This equation, in spherical coordinates, is examined for toroidal solutions to describe low $\\beta$ Solovev and high $\\beta$ plasma equilibria in terms of elementary functions.

  14. Collisionless current sheet equilibria (United States)

    Neukirch, T.; Wilson, F.; Allanson, O.


    Current sheets are important for the structure and dynamics of many plasma systems. In space and astrophysical plasmas they play a crucial role in activity processes, for example by facilitating the release of magnetic energy via processes such as magnetic reconnection. In this contribution we will focus on collisionless plasma systems. A sensible first step in any investigation of physical processes involving current sheets is to find appropriate equilibrium solutions. The theory of collisionless plasma equilibria is well established, but over the past few years there has been a renewed interest in finding equilibrium distribution functions for collisionless current sheets with particular properties, for example for cases where the current density is parallel to the magnetic field (force-free current sheets). This interest is due to a combination of scientific curiosity and potential applications to space and astrophysical plasmas. In this paper we will give an overview of some of the recent developments, discuss their potential applications and address a number of open questions.

  15. An Improved Correction for Range Restricted Correlations Under Extreme, Monotonic Quadratic Nonlinearity and Heteroscedasticity. (United States)

    Culpepper, Steven Andrew


    Standardized tests are frequently used for selection decisions, and the validation of test scores remains an important area of research. This paper builds upon prior literature about the effect of nonlinearity and heteroscedasticity on the accuracy of standard formulas for correcting correlations in restricted samples. Existing formulas for direct range restriction require three assumptions: (1) the criterion variable is missing at random; (2) a linear relationship between independent and dependent variables; and (3) constant error variance or homoscedasticity. The results in this paper demonstrate that the standard approach for correcting restricted correlations is severely biased in cases of extreme monotone quadratic nonlinearity and heteroscedasticity. This paper offers at least three significant contributions to the existing literature. First, a method from the econometrics literature is adapted to provide more accurate estimates of unrestricted correlations. Second, derivations establish bounds on the degree of bias attributed to quadratic functions under the assumption of a monotonic relationship between test scores and criterion measurements. New results are presented on the bias associated with using the standard range restriction correction formula, and the results show that the standard correction formula yields estimates of unrestricted correlations that deviate by as much as 0.2 for high to moderate selectivity. Third, Monte Carlo simulation results demonstrate that the new procedure for correcting restricted correlations provides more accurate estimates in the presence of quadratic and heteroscedastic test score and criterion relationships.

  16. Relative equilibria of vortex arrays (United States)

    Stremler, Mark


    Experiments with vibrating and oscillating cylinders have demonstrated that exotic vortex patterns can emerge in laminar wake flows. These wakes arise when more than two vortices are generated per shedding cycle. The Karman vortex street has proven to be a useful model for investigating the standard wake flow with two vortices per period; this utility suggests that it will be instructive to investigate other singly-periodic point vortex configurations that move without change of shape or size. The existence and structure of such relative equilibria of vortex arrays will be presented. Motivation for investigating these equilibria, all of which appear to be unstable, comes from the observation that the dynamics of a system slows down in the vicinity of unstable equilibria. Thus, states close to these equilibria can remain for a relatively long time, as illustrated by recent experiments in strongly magnetized electron plasma. The investigation of the relative equilibria of vortex arrays can thus provide a `road-map' for states that may be observable in laminar wake experiments.

  17. Equilibria of oligomeric proteins under high pressure - A theoretical description. (United States)

    Ingr, Marek; Kutálková, Eva; Hrnčiřík, Josef; Lange, Reinhard


    High pressure methods have become a useful tool for studying protein structure and stability. Using them, various physico-chemical processes including protein unfolding, aggregation, oligomer dissociation or enzyme-activity decrease were studied on many different proteins. Oligomeric protein dissociation is a process that can perfectly utilize the potential of high-pressure techniques, as the high pressure shifts the equilibria to higher concentrations making them better observable by spectroscopic methods. This can be especially useful when the oligomeric form is highly stable at atmospheric pressure. These applications may be, however, hindered by less intensive experimental response as well as interference of the oligomerization equilibria with unfolding or aggregation of the subunits, but also by more complex theoretical description. In this study we develop mathematical models describing different kinds of oligomerization equilibria, both closed (equilibrium of monomer and the highest possible oligomer without any intermediates) and consecutive. Closed homooligomer equilibria are discussed for any oligomerization degree, while the more complex heterooligomer equilibria and the consecutive equilibria in both homo- and heterooligomers are taken into account only for dimers and trimers. In all the cases, fractions of all the relevant forms are evaluated as functions of pressure and concentration. Significant points (inflection points and extremes) of the resulting transition curves, that can be determined experimentally, are evaluated as functions of pressure and/or concentration. These functions can be further used in order to evaluate the thermodynamic parameters of the system, i.e. atmospheric-pressure equilibrium constants and volume changes of the individual steps of the oligomer-dissociation processes. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Total ozone patterns over the northern mid-latitudes: spatial correlations, extreme events and dynamical contributions (United States)

    Rieder, H. E.; Staehelin, J.; Maeder, J. A.; Ribatet, M.; Bodeker, G. E.; Davison, A. C.


    Tools from geostatistics and extreme value theory are applied to analyze spatial correlations in total ozone for the northern mid-latitudes. The dataset used in this study is the NIWA combined total ozone dataset (Bodeker et al., 2001; Müller et al., 2008). New tools from extreme value theory (Coles, 2001; Ribatet, 2007) have recently been applied to the world's longest total ozone record from Arosa, Switzerland (e.g. Staehelin 1998a,b), in order to describe extreme events in low and high total ozone (Rieder et al., 200x). Within the current study, patterns in spatial correlation and frequency distributions of extreme events (e.g. ELOs and EHOs) are studied for the northern mid-latitudes. New insights in spatial patterns of total ozone for the northern mid-latitudes are presented. Koch et al. (2005) found that the increase in fast isentropic transport of tropical air to northern mid-latitudes contributed significantly to ozone changes between 1980 and 1989. Within this study the influence of changes in atmospheric dynamics (e.g. tropospheric and lower stratospheric pressure systems) on column ozone over the northern mid-latitudes is analyzed for the time period 1979-2007. References: Bodeker, G.E., J.C. Scott, K. Kreher, and R.L. McKenzie, Global ozone trends in potential vorticity coordinates using TOMS and GOME intercompared against the Dobson network: 1978-1998, J. Geophys. Res., 106 (D19), 23029-23042, 2001. Coles, S.: An Introduction to Statistical Modeling of Extreme Values, Springer Series in Statistics, ISBN:1852334592, Springer, Berlin, 2001. Koch, G., H. Wernli, C. Schwierz, J. Staehelin, and T. Peter (2005), A composite study on the structure and formation of ozone miniholes and minihighs over central Europe, Geophys. Res. Lett., 32, L12810, doi:10.1029/2004GL022062. Müller, R., Grooß, J.-U., Lemmen, C., Heinze, D., Dameris, M., and Bodeker, G.: Simple measures of ozone depletion in the polar stratosphere, Atmos. Chem. Phys., 8, 251-264, 2008. Ribatet

  19. Total ozone patterns over the southern mid-latitudes: spatial correlations, extreme events and dynamical contributions (United States)

    Rieder, Harald E.; di Rocco, Stefania; Staehelin, Johannes; Maeder, Jörg A.; Ribatet, Mathieu; Peter, Thomas; Davison, Anthony C.


    Tools from geostatistics and extreme value theory are applied to analyze spatial correlations in total ozone for the southern mid-latitudes. The dataset used in this study is the NIWA-assimilated total ozone dataset (Bodeker et al., 2001; Müller et al., 2008). Recently new tools from extreme value theory (Coles, 2001; Ribatet, 2007) have been applied to the world's longest total ozone record from Arosa, Switzerland (e.g. Staehelin 1998a,b) and 5 other long-term ground based stations to describe extreme events in low and high total ozone (Rieder et al., 2010a,b,c). Excursions in the frequency of extreme events reveal "fingerprints" of dynamical factors such as ENSO or NAO, and chemical factors, such as cold Arctic vortex ozone losses, as well as major volcanic eruptions of the 20th century (e.g. Gunung Agung, El Chichón, Mt. Pinatubo). Furthermore, atmospheric loading in ozone depleting substances lead to a continuous modification of column ozone in the northern hemisphere also with respect to extreme values (partly again in connection with polar vortex contributions). It is shown that application of extreme value theory allows the identification of many more of such fingerprints than conventional time series analysis on basis of annual and seasonal mean values. Especially, the analysis shows the strong influence of dynamics, revealing that even moderate ENSO and NAO events have a discernible effect on total ozone (Rieder et al., 2010b,c). Within the current study patterns in spatial correlation and frequency distributions of extreme events (e.g. ELOs and EHOs) are studied for the southern mid-latitudes. It is analyzed if "fingerprints"found for features in the northern hemisphere occur also in the southern mid-latitudes. New insights in spatial patterns of total ozone for the southern mid-latitudes are presented. Within this study the influence of changes in atmospheric dynamics (e.g. tropospheric and lower stratospheric pressure systems, ENSO) as well as

  20. Nematic Equilibria on a Two-Dimensional Annulus

    KAUST Repository

    Lewis, A. H.


    We study planar nematic equilibria on a two-dimensional annulus with strong and weak tangent anchoring, in the Oseen–Frank theoretical framework. We analyze a radially invariant defect-free state and compute analytic stability criteria for this state in terms of the elastic anisotropy, annular aspect ratio, and anchoring strength. In the strong anchoring case, we define and characterize a new spiral-like equilibrium which emerges as the defect-free state loses stability. In the weak anchoring case, we compute stability diagrams that quantify the response of the defect-free state to radial and azimuthal perturbations. We study sector equilibria on sectors of an annulus, including the effects of weak anchoring and elastic anisotropy, giving novel insights into the correlation between preferred numbers of boundary defects and the geometry. We numerically demonstrate that these sector configurations can approximate experimentally observed equilibria with boundary defects.

  1. Measurement of the deformation of an extremely flexible rotor blade using digital image correlation (United States)

    Sicard, Jérôme; Sirohi, Jayant


    This paper describes the measurement of the deformation of an extremely flexible rotor blade in hover using a novel application of three-dimensional digital image correlation (3D DIC). In this optical method, images of the rotor blade painted with a high-contrast, random speckle pattern are captured using two digital cameras and a strobe light. Photogrammetry is used to calculate a whole-field, three-dimensional map of the rotor blade. Cross-correlation between images captured under two load conditions is used to calculate deformation. The technique was first validated in the rotating frame by correlating DIC measurements on a stiff rotor blade of known geometry with measurements made by two other laser sensors. The technique was then used to measure the deformation of extremely flexible blades on a 46 cm diameter rotor, rotating at 1200 RPM. The blades of this rotor are so flexible that they can be rolled up into a compact volume. The spanwise variation of extension, lead-lag and flap bending, as well as pitch angle, were extracted from DIC measurements. The technique yielded surface heights with a spatial resolution of 0.15 mm and three-dimensional deformation vectors with a spatial resolution of 2.37 mm (1.04% of the rotor radius), at a calculated accuracy of 15 μm. Tip displacement of up to 7.59 mm (3.3% of the rotor radius) and a tip twist of up to 10.8° were measured. Based on DIC measurements, it is concluded that an accurate aeroelastic model of the rotor blade must include flap and lead-lag bending as well as twist degrees of freedom. In addition, the elastic twist must be considered of the same order of magnitude as the blade root pitch. Finally, the scalability of this technique to the measurement of full-scale rotor blade deformation is discussed.

  2. Partial Cooperative Equilibria: Existence and Characterization

    Directory of Open Access Journals (Sweden)

    Amandine Ghintran


    Full Text Available We study the solution concepts of partial cooperative Cournot-Nash equilibria and partial cooperative Stackelberg equilibria. The partial cooperative Cournot-Nash equilibrium is axiomatically characterized by using notions of rationality, consistency and converse consistency with regard to reduced games. We also establish sufficient conditions for which partial cooperative Cournot-Nash equilibria and partial cooperative Stackelberg equilibria exist in supermodular games. Finally, we provide an application to strategic network formation where such solution concepts may be useful.

  3. MHD stability for a class of tokamak equilibria with fixed boundary

    Energy Technology Data Exchange (ETDEWEB)

    Kerner, W


    The stability behavior with respect to internal modes is discussed for a class of tokamak equilibria with non-circular cross-sections and essentially flat current profiles. The stability analysis is performed numerically with the help of a normal mode code, which extremizes the Lagrangian of the system. It is found that the Mercier criterion is both necessary and sufficient for stability. Strong numerical evidence for this result is given. MHD-stable high-beta equilibria exist in this model.

  4. Academic Achievement Deficits and Their Neuropsychological Correlates in Children Born Extremely Preterm. (United States)

    Akshoomoff, Natacha; Joseph, Robert M; Taylor, H Gerry; Allred, Elizabeth N; Heeren, Timothy; OʼShea, Thomas M; Kuban, Karl C K


    The purpose of this study was to examine the risks associated with learning disabilities (LDs) in a large sample of children born extremely preterm. We predicted higher than expected rates of LD, particularly in math, and children with LD in math, reading, or both would have lower intelligence quotients (IQs) and specific patterns of neuropsychological deficits. We evaluated academic achievement, rates of LD, and their neuropsychological correlates in the Extremely Low Gestational Age Newborns (ELGANs) Study cohort of 10-year-old children born at 23 to 27 weeks gestational age. Primary analyses focused on children without intellectual disability (verbal IQ > 70 and nonverbal IQ > 70; N = 668). Low achievement was defined as a standard score ≤85 on the reading or math measures. The risk of low math achievement scores (27%) was 1.5 times higher than the risk of low reading achievement scores (17%). Children were classified as having LD based on low achievement criteria in reading only (RD, 6.4% of sample), math only (MD, 16.2%), both reading and math (RD/MD, 8.3%), or no reading or math disabilities (No LD, 69.1%). Although all 3 LD groups had multiple neuropsychological weaknesses compared with the No LD group, the RD and MD groups had different patterns of neuropsychological impairment. These children from the ELGAN cohort had higher than expected rates of LD, particularly in mathematics, even after taking socioeconomic status into consideration. These results indicate specific cognitive weaknesses that differ between extremely preterm children with RD and MD.

  5. Neoadjuvant radiation in primary extremity liposarcoma: correlation of MRI features with histopathology

    Energy Technology Data Exchange (ETDEWEB)

    Wortman, Jeremy R. [Harvard Medical School, Department of Radiology, Brigham and Women' s Hospital, Boston, MA (United States); Tirumani, Sree Harsha; Shinagare, Atul B.; Jagannathan, Jyothi P.; Ramaiya, Nikhil H. [Harvard Medical School, Department of Radiology, Brigham and Women' s Hospital, Boston, MA (United States); Harvard Medical School, Department of Imaging, Dana-Farber Cancer Institute, Boston, MA (United States); Tirumani, Harika [Harvard Medical School, Department of Imaging, Dana-Farber Cancer Institute, Boston, MA (United States); University of Arkansas Medical Sciences, Department of Radiology, Little Rock, AR (United States); Hornick, Jason L. [Harvard Medical School, Department of Pathology, Brigham and Women' s Hospital, Boston, MA (United States)


    To evaluate MRI features of response of primary extremity liposarcoma (LPS) to neoadjuvant radiation therapy (RT) with histopathologic correlation. In this IRB-approved study including 125 patients with extremity LPS treated with neoadjuvant RT from 2000 to 2013, MRI of the primary tumour in 18 patients (5 pleomorphic LPS, 13 myxoid LPS) before and after RT were reviewed by two radiologists by consensus. Histopathology of the surgical specimens was reviewed by a pathologist with expertise in sarcomas. In the pleomorphic LPS cohort, 3/5 tumours increased in size; 3/5 decreased in enhancing component; and 3/5 increased in peritumoral oedema, intratumoral haemorrhage, and necrosis. In the myxoid LPS cohort, 12/13 tumours decreased in size, 8/13 decreased in enhancing component, and 5/13 increased in internal fat following RT. Histopathology showed ≥50 % residual tumour in 1/5 pleomorphic LPS and 2/13 myxoid LPS. Hyalinization/necrosis of ≥75 % was noted in 4/5 pleomorphic LPS and 11/13 myxoid LPS. Cytodifferentiation was noted in 1/5 pleomorphic and 9/13 myxoid LPS. While pleomorphic LPS showed an increase in size, peritumoral oedema, intratumoral haemorrhage, and necrosis on MRI following neoadjuvant RT, myxoid LPS showed a decrease in size and enhancement with an increase in internal fat. (orig.)

  6. Intravascular papillary endothelial hyperplasia of the extremities: MR imaging findings with pathologic correlation

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sang Hoon [Department of Diagnostic Radiology, Brain Korea 21 project for Medical Science, Yonsei University College of Medicine, 132 Shinchondong, Seodaemoon-gu, 120-752, Seoul (Korea); Department of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea); Suh, Jin-Suck; Lim, Byung Il [Department of Diagnostic Radiology, Brain Korea 21 project for Medical Science, Yonsei University College of Medicine, 132 Shinchondong, Seodaemoon-gu, 120-752, Seoul (Korea); Yang, Woo Ick [Department of Pathology, Yonsei University College of Medicine, Seoul (Korea); Shin, Kyoo-Ho [Department of Orthopedic Surgery, Yonsei University College of Medicine, Seoul (Korea)


    We report the MRI findings of three cases of intravascular papillary endothelial hyperplasia (IPEH) of the extremities with correlation of the pathologic findings. The IPEH is a non-neoplastic reactive lesion within the vessels and is commonly associated with thrombi. Signal intensity of the IPEH is complex due to the thrombi and the PEH itself. The thrombi are characterized by a slightly hyperintense signal on T1- and T2-weighted images compared with that of muscle when it comes at the medium stage of hemorrhage. Papillary endothelial hyperplastic tissue appears either as iso- or hyperintense to the muscle on T2- and T1-weighted images and shows variable enhancement on Gd-DTPA-enhanced images. (orig.)

  7. Equilibria in Quantitative Reachability Games (United States)

    Brihaye, Thomas; Bruyère, Véronique; de Pril, Julie

    In this paper, we study turn-based quantitative multiplayer non zero-sum games played on finite graphs with reachability objectives. In this framework each player aims at reaching his own goal as soon as possible. We prove existence of finite-memory Nash (resp. secure) equilibria in multiplayer (resp. two-player) games.

  8. Single-Molecule characterization of oligomerization kinetics and equilibria of the tumor suppressor p53. (United States)

    Rajagopalan, Sridharan; Huang, Fang; Fersht, Alan R


    The state of oligomerization of the tumor suppressor p53 is an important factor in its various biological functions. It has a well-defined tetramerization domain, and the protein exists as monomers, dimers and tetramers in equilibrium. The dissociation constants between oligomeric forms are so low that they are at the limits of measurement by conventional methods in vitro. Here, we have used the high sensitivity of single-molecule methods to measure the equilibria and kinetics of oligomerization of full-length p53 and its isolated tetramerization domain, p53tet, at physiological temperature, pH and ionic strength using fluorescence correlation spectroscopy (FCS) in vitro. The dissociation constant at 37 °C for tetramers dissociating into dimers for full-length p53 was 50 ± 7 nM, and the corresponding value for dimers into monomers was 0.55 ± 0.08 nM. The half-lives for the two processes were 20 and 50 min, respectively. The equivalent quantities for p53tet were 150 ± 10 nM, 1.0 ± 0.14 nM, 2.5 ± 0.4 min and 13 ± 2 min. The data suggest that unligated p53 in unstressed cells should be predominantly dimeric. Single-molecule FCS is a useful procedure for measuring dissociation equilibria, kinetics and aggregation at extreme sensitivity.

  9. Imaging findings of intravascular papillary endothelial hyperplasia presenting in extremities: correlation with pathological findings

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sun Joo; Choo, Hye Jung; Park, Ji Sung; Park, Yeong-Mi; Eun, Choong Ki [Pusan Paik Hospital, Department of Radiology, College of Medicine, Inje University, Pusan (Korea); Hong, Sung Hwan [Seoul National University College of Medicine, Department of Radiology, Seoul (Korea); Hwang, Ji Young [Ewha Womans University, Department of Radiology, School of Medicine, Seoul (Korea); Lee, In Sook [Pusan National University Hospital, Department of Radiology, Pusan National University School of Medicine, Pusan (Korea); Lee, Jongmin [Kyungpook National University, Department of Radiology, School of Medicine, Daegu (Korea); Jung, Soo-Jin [Pusan Paik Hospital, Department of Pathology, College of Medicine, Inje University, Pusan (Korea)


    To describe magnetic resonance imaging (MRI) and ultrasound (US) findings of intravascular papillary endothelial hyperplasia (IPEH) arising in extremities. Six patients with IPEH confirmed by surgical resection were reviewed retrospectively. Before resection, 3 patients underwent both MRI and US and 3 patients underwent only MRI. Two radiologists retrospectively reviewed MR/US imaging results and correlated them with pathological features. The 6 IPEHs were diagnosed as 4 mixed forms and 2 pure forms. The pre-existing pathology of four mixed forms was intramuscular or intermuscular hemangioma. By MRI, the mixed form of IPEH (n = 4) revealed iso- to slightly high signal intensity containing nodule-like foci of high signal intensity on T1-weighted images (T1WI) and high signal intensity-containing nodule-like foci of low signal intensity on T2-weighted images (T2WI). The pure form of IPEH (n = 2) showed homogeneous iso- signal intensity on T1WI and high and low signal intensity containing nodule-like foci of low signal intensity on T2WI. On gadolinium-enhanced fat-suppressed T1WI, 50% of cases (n = 3: mixed forms) revealed peripheral, septal, and central enhancement. The other IPEHs (n = 3: 1 mixed and 2 pure forms) showed peripheral and septal enhancement or only peripheral enhancement. By US, two mixed forms of IPEH showed well-defined hypoechoic masses containing hyperechoic septa and central portion with vascularities. One pure form of IPEH was a homogeneous hypoechoic mass with septal and peripheral vascularities on color Doppler imaging. The foci of high signal intensity on T1WI, foci of low signal intensity on T2WI, and non-enhancing portions on MRI and the hypoechoic portion on US were histopathologically correlated with thrombi and the peripheral/septal or central enhancing areas on MRI, hyperechoic septa and the central portion on US, and septal/central or peripheral vascularities on color Doppler imaging corresponded to hypertrophic papillary epithelium and

  10. Phase equilibria basic principles, applications, experimental techniques

    CERN Document Server

    Reisman, Arnold


    Phase Equilibria: Basic Principles, Applications, Experimental Techniques presents an analytical treatment in the study of the theories and principles of phase equilibria. The book is organized to afford a deep and thorough understanding of such subjects as the method of species model systems; condensed phase-vapor phase equilibria and vapor transport reactions; zone refining techniques; and nonstoichiometry. Physicists, physical chemists, engineers, and materials scientists will find the book a good reference material.

  11. Correlation of PUV and SUV in the extremities while using PEM as a high-resolution positron emission scanner

    Energy Technology Data Exchange (ETDEWEB)

    Rahim, Sania [The University of Texas MD Anderson Cancer Center, Division of Diagnostic Imaging, Houston, TX (United States); MD Anderson Cancer Center, Houston, TX (United States); Mawlawi, Osama; Taylor, Shree; Millican, Richelle; Swanston, Nancy M.; Rohren, Eric M. [The University of Texas MD Anderson Cancer Center, Division of Diagnostic Imaging, Houston, TX (United States); Fox, Patricia [The University of Texas MD Anderson Cancer Center, Division of Biostatistics, Houston, TX (United States); Brown, J.E. [Yale University Hospital, Department of Radiology, New Haven, CT (United States)


    Owing to its unique configuration of two adjustable plate detectors positron emission mammography, or PEM, could theoretically also function as a high-resolution positron emission scanner for the extremities or neck. PEM quantitates its activity via a ''PEM uptake value,'' or PUV, and although its relationship to the standardized uptake value, or SUV, has been demonstrated in the breasts, to our knowledge there are no studies validating PUV in other sites such as the extremities. This was a retrospective chart review of two separate protocols of a total of 15 patients. The patients all had hypermetabolic lesions in the extremities or neck on imaging with PET/CT and were sent after their PET/CT to PEM for further imaging. Owing to the sequential nature of these examinations no additional radiotracer was administered. Spearman's rank order correlation was calculated between the PUVmax obtained from PEM images, and the SUVmax for all. Spearman's rank order correlation for all sites was 0.42, which is not significantly different from 0 (p = 0.13). When neck lesions were excluded from the group, there was a strong and statistically significant correlation between PUVmax and SUVmax, with Spearman's rank correlation of 0.73, and significantly different from 0 (p = 0.0068). The correlation of PUV and SUV in the extremities indicates the potential use of PEM as a semiquantitative, high-resolution positron emission scanner and warrants further investigation, especially in the realms of disease processes that often present in the extremities, such as melanoma, osteomyelitis, and arthritis, as well as playing a role in the imaging of patients with metallic hardware post-limb salvage surgery. (orig.)

  12. MHD equilibria with diamagnetic effects (United States)

    Tessarotto, M.; Zorat, R.; Johnson, J. L.; White, R. B.


    An outstanding issue in magnetic confinement is the establishment of MHD equilibria with enhanced flow shear profiles for which turbulence (and transport) may be locally effectively suppressed or at least substantially reduced with respect to standard weak turbulence models. Strong flows develop in the presence of equilibrium E× B-drifts produced by a strong radial electric field, as well as due to diamagnetic contributions produced by steep equilibrium radial profiles of number density, temperature and the flow velocity itself. In the framework of a kinetic description, this generally requires the construction of guiding-center variables correct to second order in the relevant expansion parameter. For this purpose, the Lagrangian approach developed recently by Tessarotto et al. [1] is adopted. In this paper the conditions of existence of such equilibria are analyzed and their basic physical properties are investigated in detail. 1 - M. Pozzo, M. Tessarotto and R. Zorat, in Theory of fusion Plasmas, E.Sindoni et al. eds. (Societá Italiana di Fisica, Editrice Compositori, Bologna, 1996), p.295.

  13. Phase diagrams and heterogeneous equilibria a practical introduction

    CERN Document Server

    Predel, Bruno; Pool, Monte


    This graduate-level textbook provides an introduction to the practical application of phase diagrams. It is intended for students and researchers in chemistry, metallurgy, mineralogy, and materials science as well as in engineering and physics. Heterogeneous equilibria are described by a minimum of theory illustrated by practical examples and realistic case discussions from the different fields of application. The treatment of the physical and energetic background of phase equilibria leads to the discussion of the thermodynamics of mixtures and the correlation between energetics and composition. Thus, tools for the prediction of energetic, structural, and physical quantities are provided. The authors treat the nucleation of phase transitions, the production and stability of technologically important metastable phases, and metallic glasses. Furthermore, the text also concisely presents the thermodynamics and composition of polymer systems.

  14. Correlation and Prediction of Phase Equilibria and Volumetric Behaviour of Hyperbaric Binary Fluids Corrélation et prédiction des équilibres de phases et du comportement volumétrique de fluides hyperbares binaires

    Directory of Open Access Journals (Sweden)

    Stamataki S. K.


    Full Text Available The capabilities of cubic Equations of State (EoS in the correlation and the prediction of phase equilibria at hyperbaric conditions is examined. PVT data of pure compounds as well as VLE and volumetric data of binary mixtures up to 2000 bar are used. Correlation and prediction results are presented with the translated and modified Peng-Robinson (t - mPR EoS and EoS/GE models. The performance of cubic EoS with a single interaction parameter (kij in describing VLE is remarkable considering the level of pressures involved. The same is valid for the PVT results including the relative liquid volumes of the C1/nC24 system. With typical errors of about 10% deviations in pressure of 100 - 200 bar are, of course, encountered which can be eliminated by the use of second interaction coefficient in the covolume combining rule. Predicted kij values obtained from generalized correlations developed from low pressure VLE data provide reasonable results for systems with hydrocarbons up to nC16 even at high pressures, but fail for higher asymmetric ones. Volume translation is essential for PVT predictions. The temperature independent translation of t - mPR and that of Jhaveri and Yougren give very satisfactory results. LCVM provides the best results of the EoS/GE models studied and gives very good predictions for rather symmetric systems which become poorer with asymmetric ones at very high pressures. La capacité des équations d'état (EoS cubiques pour corréler et prédire les équilibres de phases en conditions hyperbares est analysée. Les données PVT de corps purs ainsi que les données d'équilibres liquide-vapeur (VLE et volumétriques pour des mélanges binaires, jusqu'à 2000 bar sont utilisées. Les résultats des corrélations et des prédictions sont présentés pour l'équation de Peng-Robinson translatée et modifiée (t - mPR, ainsi que pour les modèles EoS/GE. Les performances des EoS cubiques avec un paramètre d'interaction unique (kij pour

  15. Extended UNIQUAC Model for Correlation and Prediction of Vapor-Liquid-Liquid-Solid Equilibria in Aqueous Salt Systems Containing Non-Electrolytes. Part B. Alcohol (Ethanol, Propanols, Butanols) - Water-salt systems

    DEFF Research Database (Denmark)

    Thomsen, Kaj; Iliuta, Maria Cornelia; Rasmussen, Peter


    -Redlich-Kwong equation of state. The model only requires binary, temperature-dependent interaction parameters. It has previously been used to describe the excess Gibbs energy for aqueous electrolyte mixtures and aqueous electrolyte systems containing methanol. It has been found to be an adequate model for representing......, and liquid-liquid equilibrium data for solvent mixtures and for mixed solvent-electrolyte systems. The application of this model to represent the vapor-liquid-liquid-solid equilibria in aqueous systems containing various non-electrolytes (ethanol, 1-propanol, 2-propanol, 1-butanol, 2- butanol, 2-methyl I...... solid-liquid-vapor equilibrium and thermal property data for strongly non-ideal systems. In this work, the model is extended to aqueous salt systems containing higher alcohols. The calculations are based on an extensive database consisting of salt solubility data, vapor liquid equilibrium data...

  16. On the topological stability of magnetostatic equilibria (United States)

    Tsinganos, K. C.; Rosner, R.; Distler, J.


    The topological stability of MHD equilibria is investigated by exploring the formal analogy, in the ideal MHD limit, between the topology of magnetic lines of force in coordinate space and the topology of integral surfaces of one- and two-dimensional Hamiltonian systems in phase space. It is demonstrated that in an astrophysical setting, symmetric magnetostatic equilibria satisfying the ideal MHD equations are exceptional. The principal result of the study is that previous infinitesimal perturbation theory calculations can be generalized to include finite-amplitude and symmetry-breaking effects. The effect of the ergodicity of perturbed symmetric equilibria on heat dispersal in magnetically dominated plasmas is discussed.

  17. Motion Control along Relative Equilibria

    DEFF Research Database (Denmark)

    Nordkvist, Nikolaj


    The subject of this thesis is control of mechanical systems as they evolve along the steady motions called relative equilibria. These trajectories are of interest in theory and applications and have the characterizing property that the system's body-fixed velocity is constant. For example, constant......-speed rotation about a principal axis is a relative equilibrium of a rigid body in three dimensions. We focus our study on simple mechanical control systems on Lie groups, i.e., mechanical systems with the following properties: the configuration manifold is a matrix Lie group, the total energy is equal...... on a Lie group is locally controllable along a relative equilibrium. These conditions subsume the well-known local controllability conditions for equilibrium points. Second, for systems that have fewer controls than degrees of freedom, we present a novel algorithm to control simple mechanical control...

  18. Inefficient equilibria in transition economy

    Directory of Open Access Journals (Sweden)

    Sergei Guriev


    Full Text Available The paper studies a general equilibrium in an economy where all market participants face a bid-ask spread. The spread may be caused by indirect business taxes, middlemen rent-seeking, delays in payments or liquidity constraints or price uncertainty. Wherever it comes from the spread causes inefficiency of the market equilibrium. We discuss some institutions that can decrease the inefficiency. One is second currency (barter exchange in the inter-firm transactions. It is shown that the general equilibrium in an economy with second currency is effective though is still different from Arrow–Debreu equilibrium. Another solution can be introduction of mutual trade credit. In the economy with trade credit there are multiple equilibria that are more efficient than original bid-ask spread but still not as efficient as Arrow–Debreu one, too. The implications for firms' integration and applicability to Russian economy are discussed.

  19. A Continuous Family of Equilibria in Ferromagnetic Media are Ground States (United States)

    Su, Xifeng; de la Llave, Rafael


    We show that a foliation of equilibria (a continuous family of equilibria whose graph covers all the configuration space) in ferromagnetic transitive models are ground states. The result we prove is very general, and it applies to models with long range and many-body interactions. As an application, we consider several models of networks of interacting particles including models of Frenkel-Kontorova type on Z^d and one-dimensional quasi-periodic media. The result above is an analogue of several results in the calculus of variations (fields of extremals) and in PDE's. Since the models we consider are discrete and long range, new proofs need to be given. We also note that the main hypothesis of our result (the existence of foliations of equilibria) is the conclusion (using KAM theory) of several recent papers. Hence, we obtain that the KAM solutions recently established are minimizers when the interaction is ferromagnetic and transitive (these concepts are defined later).

  20. Generalized randomly amplified linear system driven by gaussian noises: extreme heavy tail and algebraic correlation decay in plasma turbulence. (United States)

    Steinbrecher, György; Weyssow, B


    The extreme heavy tail and the power-law decay of the turbulent flux correlation observed in hot magnetically confined plasmas are modeled by a system of coupled Langevin equations describing a continuous time linear randomly amplified stochastic process where the amplification factor is driven by a superposition of colored noises which, in a suitable limit, generate a fractional Brownian motion. An exact analytical formula for the power-law tail exponent beta is derived. The extremely small value of the heavy tail exponent and the power-law distribution of laminar times also found experimentally are obtained, in a robust manner, for a wide range of input values, as a consequence of the (asymptotic) self-similarity property of the noise spectrum. As a by-product, a new representation of the persistent fractional Brownian motion is obtained.

  1. Correlations in condensed matter under extreme conditions a tribute to Renato Pucci on the occasion of his 70th birthday

    CERN Document Server


    This book addresses a wide range of topics relating to the properties and behavior of condensed matter under extreme conditions such as intense magnetic and electric fields, high pressures, heat and cold, and mechanical stresses. It is divided into four sections devoted to condensed matter theory, molecular chemistry, theoretical physics, and the philosophy and history of science. The main themes include electronic correlations in material systems under extreme pressure and temperature conditions, surface physics, the transport properties of low-dimensional electronic systems, applications of the density functional theory in molecular systems, and graphene. The book is the outcome of a workshop held at the University of Catania, Italy, in honor of Professor Renato Pucci on the occasion of his 70th birthday. It includes selected invited contributions from collaborators and co-authors of Professor Pucci during his long and successful career, as well as from other distinguished guest authors.

  2. Effect of extreme data loss on long-range correlated and anticorrelated signals quantified by detrended fluctuation analysis. (United States)

    Ma, Qianli D Y; Bartsch, Ronny P; Bernaola-Galván, Pedro; Yoneyama, Mitsuru; Ivanov, Plamen Ch


    Detrended fluctuation analysis (DFA) is an improved method of classical fluctuation analysis for nonstationary signals where embedded polynomial trends mask the intrinsic correlation properties of the fluctuations. To better identify the intrinsic correlation properties of real-world signals where a large amount of data is missing or removed due to artifacts, we investigate how extreme data loss affects the scaling behavior of long-range power-law correlated and anticorrelated signals. We introduce a segmentation approach to generate surrogate signals by randomly removing data segments from stationary signals with different types of long-range correlations. The surrogate signals we generate are characterized by four parameters: (i) the DFA scaling exponent alpha of the original correlated signal u(i) , (ii) the percentage p of the data removed from u(i) , (iii) the average length mu of the removed (or remaining) data segments, and (iv) the functional form P(l) of the distribution of the length l of the removed (or remaining) data segments. We find that the global scaling exponent of positively correlated signals remains practically unchanged even for extreme data loss of up to 90%. In contrast, the global scaling of anticorrelated signals changes to uncorrelated behavior even when a very small fraction of the data is lost. These observations are confirmed on two examples of real-world signals: human gait and commodity price fluctuations. We further systematically study the local scaling behavior of surrogate signals with missing data to reveal subtle deviations across scales. We find that for anticorrelated signals even 10% of data loss leads to significant monotonic deviations in the local scaling at large scales from the original anticorrelated to uncorrelated behavior. In contrast, positively correlated signals show no observable changes in the local scaling for up to 65% of data loss, while for larger percentage of data loss, the local scaling shows

  3. Stability of Magnetic Equilibria in Radio Balloons


    Benford, Gregory


    Current-carrying flows, in the laboratory and in astrophysical jets, can form remarkably stable magnetic structures. Decades of experience shows that such flows often build equilibria that reverse field directions, evolving to an MHD Taylor state, which has remarkable stability properties. We model jets and the magnetic bubbles they build as reversed field pinch equilibria by assuming the driver current to be stiff in the MHD sense. Taking the jet current as rigid and a fixed function of posi...

  4. Why mixed equilibria may not be conventions

    DEFF Research Database (Denmark)

    Hansen, Pelle Guldborg


    on dropping Lewis' eccentric ‘coordination' requirement as well as that of common knowledge, they are confused on whether conventions should be regarded as proper thereby precluding mixed equilibria. In this paper I argue that mixed equilibria may not be conventions, but also suggest that the reason...... for this reveals that though common knowledge is not necessary for a convention to operate, it may be utilized as to identify the conventional aspect of a given practice....

  5. Homotopy methods for counting reaction network equilibria


    Craciun, Gheorghe; Helton, J. William; Williams, Ruth J


    Dynamical system models of complex biochemical reaction networks are usually high-dimensional, nonlinear, and contain many unknown parameters. In some cases the reaction network structure dictates that positive equilibria must be unique for all values of the parameters in the model. In other cases multiple equilibria exist if and only if special relationships between these parameters are satisfied. We describe methods based on homotopy invariance of degree which allow us to determine the numb...

  6. Application of the CPA equation of state to glycol/hydrocarbons liquid-liquid equilibria

    DEFF Research Database (Denmark)

    Derawi, Samer; Michelsen, Michael Locht; Kontogeorgis, Georgios


    is achieved with solely a single interaction parameter per binary system. The correlation procedure as well as the nature of the experimental data play a crucial role in the parameter estimation and they are thus extensively discussed. (C) 2003 Elsevier Science B.V. All rights reserved....... shown in the past to be a successful model for phase equilibria calculations for systems containing water, hydrocarbons and alcohols. In this work, CPA is applied for the first time to liquid-liquid equilibria (LLE) for systems containing glycols and hydrocarbons. It is shown that excellent correlation...

  7. On bounded rank positive semidefinite matrix completions of extreme partial correlation matrices.

    NARCIS (Netherlands)

    M. Eisenberg-Nagy (Marianna); M. Laurent (Monique); A. Varvitsiotis (Antonios)


    htmlabstractWe study a new geometric graph parameter egd(G), defined as the smallest integer r ≥ 1 for which any partial symmetric matrix which is completable to a correlation matrix and whose entries are specified at the positions of the edges of G, can be completed to a matrix in the convex hull

  8. Correlation between bioelectrical spectroscopy and perometry in assessment of upper extremity swelling. (United States)

    Jain, M S; Danoff, J V; Paul, S M


    Lymphedema is a common side effect of breast cancer treatment and is associated with increased upper extremity volume, functional impairment, and pain. While there is no cure for lymphedema, physical therapy treatment can often alleviate symptoms. To measure the efficacy of treatment, accurate assessment of the limbs is important. Current methods of assessment are complex (water displacement), marginally accurate (circumferential measurements), or expensive (opto-electrical systems). A new method for estimating tissue fluid is bioelectrical spectroscopy (BIS). This method measures impedance to small currents applied to the body and is easily performed. Acceptance of BIS devices for assessment of limb fluid will be dependent on the establishment of sufficient reliability and validity, and the objective of this study was to evaluate reliability and validity of this device compared to perometry. Both upper limbs of ten subjects previously treated for breast cancer were measured using BIS and perometry. We found that inter-rater reliability (r = 0.987) and intrarater reliability (r = 0.993) were acceptably high for the BIS unit and concurrent validity was r = -0.904, when compared to perometry. These results confirm that BIS can produce valid and reliable data related to the assessment of upper limbs affected by lymphedema.

  9. Information Anatomy of Stochastic Equilibria

    Directory of Open Access Journals (Sweden)

    Sarah Marzen


    Full Text Available A stochastic nonlinear dynamical system generates information, as measured by its entropy rate. Some—the ephemeral information—is dissipated and some—the bound information—is actively stored and so affects future behavior. We derive analytic expressions for the ephemeral and bound information in the limit of infinitesimal time discretization for two classical systems that exhibit dynamical equilibria: first-order Langevin equations (i where the drift is the gradient of an analytic potential function and the diffusion matrix is invertible and (ii with a linear drift term (Ornstein–Uhlenbeck, but a noninvertible diffusion matrix. In both cases, the bound information is sensitive to the drift and diffusion, while the ephemeral information is sensitive only to the diffusion matrix and not to the drift. Notably, this information anatomy changes discontinuously as any of the diffusion coefficients vanishes, indicating that it is very sensitive to the noise structure. We then calculate the information anatomy of the stochastic cusp catastrophe and of particles diffusing in a heat bath in the overdamped limit, both examples of stochastic gradient descent on a potential landscape. Finally, we use our methods to calculate and compare approximations for the time-local predictive information for adaptive agents.

  10. ELM (Extreme Learning Machine Based Correlated Interference Canceller for Small Aperture Array Antenna

    Directory of Open Access Journals (Sweden)

    Junseok Lim


    Full Text Available The multipath effect creates a highly correlated interference. Subsequently, small aperture array antennas equipped in mobile devices must be able to effectively cancel this coherent interference. Spatial smoothing MMSE is a typical coherent interference cancellation algorithm; however, this method further reduces the small aperture size and reduces the number of coherent interferences to cancel out. This paper proposes a new method to reject coherent interferences without a reduction in the antenna aperture size. We show the superiority of the proposed algorithm through a comparison of cancellation performance with existing adaptive beamforming algorithms.

  11. Extreme exercise enhances chromogranin A levels correlating with stress levels but not with cardiac burden. (United States)

    Nickel, T; Vogeser, M; Emslander, I; David, R; Heilmeier, B; Op den Winkel, M; Schmidt-Trucksäss, A; Wilbert-Lampen, U; Hanssen, H; Halle, M


    Stress and heart failure are associated with increased systemic levels of chromogranin A (CGA). Here we analyzed the effects of marathon running on systemic CGA levels and the association with cardiac burden and stress. We recruited 47 lean and obese runners for a 10week training program aiming at running a marathon. Heart rates, individual fitness and marathon finishing times were monitored. CGA, proBNP and troponin T levels were analyzed by ELISA. We found a significant increase of CGA (+51%; prunners after marathon. The obese group showed the highest troponin T (0.22ng/ml; p<0.01) and proBNP (176.6ng/ml; p<0.01) levels. There were no correlations between proBNP, troponin T and CGA. An inverse correlation (r=-0.45; p<0.01) was found between CGA and finishing times. Marathon running is associated with increased CGA levels. However, this does not seem to reflect cardiac burden but rather marathon induced stress. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  12. Liquid-liquid equilibria for ternary polymer mixtures (United States)

    Oh, Suk Yung; Bae, Young Chan


    A molecular thermodynamic model for multicomponent systems based on a closed-packed lattice model is presented based on two contributions; entropy and energy contribution. The calculated liquid-liquid equilibria of ternary chainlike mixtures agreed with Monte Carlo simulation results. The proposed model can satisfactorily predict Types 0, 1, 2 and 3 phase separations of the Treybal classification. The model parameters obtained from the binary systems were used to directly predict real ternary systems and the calculated results correlated well with experimental data using few adjustable parameters. Specific interactions in associated binary systems were considered using a secondary lattice.

  13. ASDEX upgrade MHD equilibria reconstruction on distributed workstations

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, W. E-mail:; McCarthy, P.J.; Lackner, K.; Gruber, O.; Behler, K.; Martin, P.; Merkel, R


    The identification of MHD equilibrium states on the ASDEX Upgrade tokamak is a prerequisite for interpreting measurements from a wide range of diagnostics which are correlated with the shape of the plasma. The availability in realtime of plasma parameters related to the MHD state is crucial for controlling the experiment. Function Parameterization is used as a standard tool to determine the position, shape, and other global parameters of the plasma as well as the MHD equilibrium flux surfaces. The recently developed interpretive equilibrium code CLISTE now enables the calculation of MHD equilibria on an intershot timescale. These calculations are parallelized by the use of a Message Passing Interface (MPI)

  14. Long-time correlations in company profit fluctuations: presence of extreme events. (United States)

    Roman, H Eduardo; Siliprandi, Riccardo A; Dose, Christian; Porto, Markus


    The accuracy of earnings predictions is hampered by the several predominantly unpredictable effects due to the complex evolution of economy. Finding out which are the dominant market features embracing uncertainty is therefore the key to get beyond present state-of-art earnings forecasts. The analysis of annual revenues and earnings data (1954-2008) from the 500 largest-revenue U.S. companies suggests a linear relation between company expected mean profit and revenue. Annual profit fluctuations are then obtained as difference between actual annual profits and expected mean values. It is found that the temporal evolution of profit fluctuations for a single company displays a slowly decaying autocorrelation, yielding Hurst exponents in the range H=0.75+/-0.17 . The study of profits cross correlations between companies suggests a way to distinguish typical earnings years from anomalous ones by looking at minimal information structures contained within the space defined by the associated covariance metric.

  15. Long-time correlations in company profit fluctuations: Presence of extreme events (United States)

    Roman, H. Eduardo; Siliprandi, Riccardo A.; Dose, Christian; Porto, Markus


    The accuracy of earnings predictions is hampered by the several predominantly unpredictable effects due to the complex evolution of economy. Finding out which are the dominant market features embracing uncertainty is therefore the key to get beyond present state-of-art earnings forecasts. The analysis of annual revenues and earnings data (1954-2008) from the 500 largest-revenue U.S. companies suggests a linear relation between company expected mean profit and revenue. Annual profit fluctuations are then obtained as difference between actual annual profits and expected mean values. It is found that the temporal evolution of profit fluctuations for a single company displays a slowly decaying autocorrelation, yielding Hurst exponents in the range H=0.75±0.17 . The study of profits cross correlations between companies suggests a way to distinguish typical earnings years from anomalous ones by looking at minimal information structures contained within the space defined by the associated covariance metric.

  16. Extremely correlated Fermi liquid theory of the t-J model in 2 dimensions: low energy properties (United States)

    Shastry, B. Sriram; Mai, Peizhi


    Low energy properties of the metallic state of the two-dimensional t-J model are presented for second neighbor hopping with hole-doping (t\\prime ≤slant 0) and electron-doping (t\\prime > 0), with various superexchange energy J. We use a closed set of equations for the Greens functions obtained from the extremely correlated Fermi liquid theory. These equations reproduce the known low energies features of the large U Hubbard model in infinite dimensions. The density and temperature dependent quasiparticle weight, decay rate and the peak spectral heights over the Brillouin zone are calculated. We also calculate the resistivity, Hall conductivity, Hall number and cotangent Hall angle. The spectral features display high thermal sensitivity at modest T for density n≳ 0.8, implying a suppression of the effective Fermi-liquid temperature by two orders of magnitude relative to the bare bandwidth. The cotangent Hall angle exhibits a T 2 behavior at low T, followed by an interesting kink at higher T. The Hall number exhibits strong renormalization due to correlations. Flipping the sign of t\\prime changes the curvature of the resistivity versus T curves between convex and concave. Our results provide a natural route for understanding the observed difference in the temperature dependent resistivity of strongly correlated electron-doped and hole-doped matter.

  17. Renormalized Equilibria of a Schlögl Model Lattice Gas

    CERN Document Server

    Boghosian, B M; Boghosian, Bruce M.; Taylor, Washington


    A lattice gas model for Schloegl's second chemical reaction is described and analyzed. Because the lattice gas does not obey a semi-detailed-balance condition, the equilibria are non-Gibbsian. In spite of this, a self-consistent set of equations for the exact homogeneous equilibria are described, using a generalized cluster-expansion scheme. These equations are solved in the two-particle BBGKY approximation, and the results are compared to numerical experiment. It is found that this approximation describes the equilibria far more accurately than the Boltzmann approximation. It is also found, however, that spurious solutions to the equilibrium equations appear which can only be removed by including effects due to three-particle correlations.

  18. Developmental Correlates of Head Circumference at Birth and Two Years in a Cohort of Extremely Low Gestational Age Newborns (United States)

    Kuban, Karl C. K.; Allred, Elizabeth N.; O’Shea, T. Michael; Paneth, Nigel; Westra, Sjirk; Miller, Cindy; Rosman, N. Paul; Leviton, Alan


    Objectives To evaluate the developmental correlates of microcephaly evident at birth and at 2 years in a cohort born at extremely low gestational age. Methods We assessed development and motor function at 2 years of 958 children born before the 28th week of gestation, comparing those who had microcephaly at birth or 2 years with children with normal head circumference while considering the contribution of neonatal cranial ultrasound lesions. Results A total of 11% of infants in our sample had microcephaly at 2 years. Microcephaly at 2 years, but not at birth, predicts severe motor and cognitive impairments at 2 years. A total of 71% of children with congenital microcephaly had a normal head circumference at 2 years and had neurodevelopmental outcomes comparable with those with normal head circumference at birth and 2 years. Among children with microcephaly at 2 years, more than half had a Mental Developmental Index <70, and nearly a third had cerebral palsy. The risks were increased if the child also had cerebral white matter damage on a cranial ultrasound scan obtained 2 years previously. Conclusion Among extremely low gestational age newborns, microcephaly at 2 years, but not at birth, is associated with motor and cognitive impairment at age 2. PMID:19555967

  19. Symmetry transforms for ideal magnetohydrodynamics equilibria. (United States)

    Bogoyavlenskij, Oleg I


    A method for constructing ideal magnetohydrodynamics (MHD) equilibria is introduced. The method consists of the application of symmetry transforms to any known MHD equilibrium [ O. I. Bogoyavlenskij, Phys. Rev. E. 62, 8616, (2000)]. The transforms break the geometrical symmetries of the field-aligned solutions and produce continuous families of the nonsymmetric MHD equilibria. The method of symmetry transforms also allows to obtain MHD equilibria with current sheets and exact solutions with noncollinear vector fields B and V. A model of the nonsymmetric astrophysical jets outside of their accretion disks is developed. The total magnetic and kinetic energy of the jet is finite in any layer c(1)ball lightning with dynamics of plasma inside the fireball.

  20. Multiple Equilibria in Noisy Rational Expectations Economies

    DEFF Research Database (Denmark)

    Pálvölgyi, Dömötör; Venter, Gyuri

    This paper studies equilibrium uniqueness in standard noisy rational expectations economies with asymmetric or differential information a la Grossman and Stiglitz (1980) and Hellwig (1980). We show that the standard linear equilibrium of Grossman and Stiglitz (1980) is the unique equilibrium...... with a continuous price function. However, we also construct a tractable class of equilibria with discontinuous prices that have very different economic implications, including (i) jumps and crashes, (ii) significant revisions in uninformed belief due to small changes in the market price, (iii) “upward......-sloping” demand curves, (iv) higher prices leading to future returns that are higher in expectation (price drift) and (v) more positively skewed. Discontinuous equilibria can be arbitrarily close to being fully-revealing. Finally, discontinuous equilibria with the same construction also exist in Hellwig (1980)....

  1. Exact solutions for helical magnetohydrodynamic equilibria

    Energy Technology Data Exchange (ETDEWEB)

    Villata, M. (Istituto di Fisica Generale, Universita di Torino, Via Pietro Giuria 1, I-10125 Torino (Italy)); Tsinganos, K. (Department of Physics, University of Crete and Research Center of Crete, GR-71409, Heraklion, Crete (Greece))


    Three novel classes of exact solutions of the generalized Grad--Shafranov equation for helically symmetric magnetohydrodynamic (MHD) equilibria are presented. The first two classes may be applied to helical MHD equilibria for plasma confined between two coaxial cylinders, while the third one to the modeling of helicoidal magnetic fields and flows in several recently observed astrophysical jets. The same solutions can be also used for the testing of sophisticated numerical codes. It is also shown that all helically symmetric MHD equilibria can be treated by the same general method which is employed to generate exact MHD solutions for systems possessing an ignorable coordinate in a system of three orthogonal basis vectors, although in the case of helical symmetry an [ital orthogonal] ignorable coordinate does not exist, contrary to what happens in the well-known cases of axial and translational symmetries.

  2. Existence of pareto equilibria for multiobjective games without compactness


    Shiraishi, Yuya; Kuroiwa, Daishi


    In this paper, we investigate the existence of Pareto and weak Pareto equilibria for multiobjective games without compactness. By employing an existence theorem of Pareto equilibria due to Yu and Yuan([10]), several existence theorems of Pareto and weak Pareto equilibria for the multiobjective games are established in a similar way to Flores-B´azan.

  3. State-of-the-art review of phase equilibria

    Energy Technology Data Exchange (ETDEWEB)

    Prausnitz, J.M.


    High-pressure phase-equilibrium calculations using an equation of state are more sensitive to the mixing rules than to details in the effect of density or temperature on pressure. Attention must be given to the problem of how to extend equations of state to mixtures. One possible technique is provided by perturbation theory; another by superposition of chemical equilibria. At low or moderate pressures, vapor-phase corrections are often important. When specific intermolecular forces produce formation of molecular aggregates, strong deviations from ideal-gas behavior can be significant even at pressures well below 1 bar. When vapor-liquid equilibrium data are reduced using conventional expressions for the excess Gibbs energy, the resulting binary parameters tend to be partially correlated, it difficult, but no impossible, to calculate ternary liquid-liquid equilibria using binary parameters only. New models for calculating properties of liquid-phase mixtures mist allow for changes in free volume to give consideration to the effect of mixing on changes in rotational and vibrational degrees of freedom. Liquid-phase volumetric effects are also important in describing the solubilities of gases in solvent mixtures. Therefore, future liquid-phase models should incorporate a liquid-phase equation of state, either of the van der Waals type or, perhaps, as given by the direct-correlation function theory of liquids.

  4. Multiple Equilibria in a Single-Column Model of the Tropical Atmosphere

    CERN Document Server

    Sobel, Adam H; Bacmeister, Julio T


    A single-column model run under the weak temperature gradient approximation, a parameterization of large-scale dynamics appropriate for the tropical atmosphere, is shown to have multiple stable equilibria. Under conditions permitting persistent deep convection, the model has a statistically steady state in which such convection occurs, as well as an extremely dry state in which convection does not occur. Which state is reached depends on the initial moisture profile.

  5. Unified regression model of binding equilibria in crowded environments (United States)

    Lee, Byoungkoo; LeDuc, Philip R.; Schwartz, Russell


    Molecular crowding is a critical feature distinguishing intracellular environments from idealized solution-based environments and is essential to understanding numerous biochemical reactions, from protein folding to signal transduction. Many biochemical reactions are dramatically altered by crowding, yet it is extremely difficult to predict how crowding will quantitatively affect any particular reaction systems. We previously developed a novel stochastic off-lattice model to efficiently simulate binding reactions across wide parameter ranges in various crowded conditions. We now show that a polynomial regression model can incorporate several interrelated parameters influencing chemistry under crowded conditions. The unified model of binding equilibria accurately reproduces the results of particle simulations over a broad range of variation of six physical parameters that collectively yield a complicated, non-linear crowding effect. The work represents an important step toward the long-term goal of computationally tractable predictive models of reaction chemistry in the cellular environment. PMID:22355615

  6. New investigation of phase equilibria in the system Al-Cu-Si. (United States)

    Ponweiser, Norbert; Richter, Klaus W


    The phase equilibria and invariant reactions in the system Al-Cu-Si were investigated by a combination of optical microscopy, powder X-ray diffraction (XRD), differential thermal analysis (DTA) and electron probe micro analysis (EPMA). Isothermal phase equilibria were investigated within two isothermal sections. The isothermal section at 500 °C covers the whole ternary composition range and largely confirms the findings of previous phase diagram investigations. The isothermal section at 700 °C describes phase equilibria only in the complex Cu-rich part of the phase diagram. A new ternary compound τ was found in the region between (Al,Cu)-γ(1) and (Cu,Si)-γ and its solubility range was determined. The solubility of Al in κ-CuSi was found to be extremely high at 700 °C. In contrast, no ternary solubility in the β-phase of Cu-Al was found, although this phase is supposed to form a complete solid solution according to previous phase diagram assessments. Two isopleths, at 10 and 40 at.% Si, were investigated by means of DTA and a partial ternary reaction scheme (Scheil diagram) was constructed, based on the current work and the latest findings in the binary systems Al-Cu and Cu-Si. The current study shows that the high temperature equilibria in the Cu-rich corner are still poorly understood and additional studies in this area would be favorable.

  7. Thermodynamic modeling of naringenin protonation equilibria in ...

    Indian Academy of Sciences (India)

    The protonation equilibria for the flavonoid naringenin were studied at 25°C using combined multiwavelength spectroscopic and pH-potentiometric methods as a function of the ionic strength. Over a wide range of ionic strengths, 0.10–3.00 mol dm−3, the investigation was performed in different aqueous solutions of NaClO4 ...

  8. Intermediates and Generic Convergence to Equilibria

    DEFF Research Database (Denmark)

    Marcondes de Freitas, Michael; Wiuf, Carsten; Feliu, Elisenda


    Known graphical conditions for the generic and global convergence to equilibria of the dynamical system arising from a reaction network are shown to be invariant under the so-called successive removal of intermediates, a systematic procedure to simplify the network, making the graphical condition...

  9. Phase equilibria of carbohydrates in polar solvents

    DEFF Research Database (Denmark)

    Jonsdottir, Svava Osk; Rasmussen, Peter


    A method for calculating interaction energies and interaction parameters with molecular mechanics methods is extended to predict solid-liquid equilibria (SLE) for saccharides in aqueous solution, giving results in excellent agreement with experimental values. Previously, the method has been shown...

  10. Relexation algorithms in finding Nash equilibria

    NARCIS (Netherlands)

    Berridge, S.; Krawczyk, J.B.


    Relaxation algorithms provide a powerful method of finding noncooperative equilibria in general synchronous games. Through use of the Nikaido-Isoda function, the Nash solution to a broad category of constrained, multiplayer, non-zerosum games can easily be found. We provide solutions to some simple

  11. Nash equilibria via duality and homological selection

    Indian Academy of Sciences (India)

    Keywords. Nash equilibria; Dold–Thom theorem; homological selection. 2010 Mathematics Subject Classification. Primary: 55M05, 55N45, 91A10. 1. Introduction. The main topological problem addressed in this paper is the following: Let X be a metric space and Subk(X) denote the collection of subsets of X with at most.

  12. Social Interactions under Incomplete Information: Games, Equilibria, and Expectations (United States)

    Yang, Chao

    My dissertation research investigates interactions of agents' behaviors through social networks when some information is not shared publicly, focusing on solutions to a series of challenging problems in empirical research, including heterogeneous expectations and multiple equilibria. The first chapter, "Social Interactions under Incomplete Information with Heterogeneous Expectations", extends the current literature in social interactions by devising econometric models and estimation tools with private information in not only the idiosyncratic shocks but also some exogenous covariates. For example, when analyzing peer effects in class performances, it was previously assumed that all control variables, including individual IQ and SAT scores, are known to the whole class, which is unrealistic. This chapter allows such exogenous variables to be private information and models agents' behaviors as outcomes of a Bayesian Nash Equilibrium in an incomplete information game. The distribution of equilibrium outcomes can be described by the equilibrium conditional expectations, which is unique when the parameters are within a reasonable range according to the contraction mapping theorem in function spaces. The equilibrium conditional expectations are heterogeneous in both exogenous characteristics and the private information, which makes estimation in this model more demanding than in previous ones. This problem is solved in a computationally efficient way by combining the quadrature method and the nested fixed point maximum likelihood estimation. In Monte Carlo experiments, if some exogenous characteristics are private information and the model is estimated under the mis-specified hypothesis that they are known to the public, estimates will be biased. Applying this model to municipal public spending in North Carolina, significant negative correlations between contiguous municipalities are found, showing free-riding effects. The Second chapter "A Tobit Model with Social

  13. Vapor-liquid equilibria for acetone + chloroform + methanol and constituent binary systems at 101. 3 kPa

    Energy Technology Data Exchange (ETDEWEB)

    Hiaki, Toshihiko (Nihon Univ., Chiba (Japan). Dept. of Industrial Chemistry); Kurihara, Kiyofumi; Kojima, Kazuo (Nihon Univ., Tokyo (Japan). Dept. of Industrial Chemistry)


    Vapor-liquid equilibria (VLE) and azeotropic data, which are useful for the design and operation of separation processes, have been observed for many systems. Isobaric vapor-liquid equilibria for acetone + chloroform + methanol and for the constituent binary systems chloroform + methanol and chloroform + acetone were measured at 101.3 kPa using a liquid-vapor ebullition-type equilibrium still. The experimental data were correlated with the extended Redlich-Kister and Wilson equations. The data were best correlated and completely calculated for the ternary and three binary azeotropic data using the extended Redlich-Kister equation.

  14. Multiple equilibria in a simple elastocapillary system

    KAUST Repository

    Taroni, Michele


    We consider the elastocapillary interaction of a liquid drop placed between two elastic beams, which are both clamped at one end to a rigid substrate. This is a simple model system relevant to the problem of surface-tension-induced collapse of flexible micro-channels that has been observed in the manufacture of microelectromechanical systems (MEMS). We determine the conditions under which the beams remain separated, touch at a point, or stick along a portion of their length. Surprisingly, we show that in many circumstances multiple equilibrium states are possible. We develop a lubrication-type model for the flow of liquid out of equilibrium and thereby investigate the stability of the multiple equilibria. We demonstrate that for given material properties two stable equilibria may exist, and show via numerical solutions of the dynamic model that it is the initial state of the system that determines which stable equilibrium is ultimately reached. © 2012 Cambridge University Press.

  15. The pressure tensor in tangential equilibria

    Directory of Open Access Journals (Sweden)

    F. Mottez


    Full Text Available The tangential equilibria are characterized by a bulk plasma velocity and a magnetic field that are perpendicular to the gradient direction. Such equilibria can be spatially periodic (like waves, or they can separate two regions with asymptotic uniform conditions (like MHD tangential discontinuities. It is possible to compute the velocity moments of the particle distribution function. Even in very simple cases, the pressure tensor is not isotropic and not gyrotropic. The differences between a scalar pressure and the pressure tensor derived in the frame of the Maxwell-Vlasov theory are significant when the gradient scales are of the order of the Larmor radius; they concern mainly the ion pressure tensor.

  16. Free boundary skin current MHD (magnetohydrodynamic) equilibria

    Energy Technology Data Exchange (ETDEWEB)

    Reusch, M.F.


    Function theoretic methods in the complex plane are used to develop simple parametric hodograph formulae which generate sharp boundary equilibria of arbitrary shape. The related method of Gorenflo and Merkel is discussed. A numerical technique for the construction of solutions, based on one of the methods is presented. A study is made of the bifurcations of an equilibrium of general form. 28 refs., 9 figs.

  17. Designing Network Protocols for Good Equilibria (United States)


    Introduction Most modern-day networks dear to computer science—from the Internet , to the Web, to peer-to- peer and social networks—are created and used by a...equilibria, a much stronger requirement than stability (2). A second parallel is provided by work in the networking community on the BGP interdomain ...Theory of Computing (STOC), pages 663–670, 2006. 36 [19] L. Gao and J. Rexford. Stable Internet routing without global coordination. IEEE/ACM

  18. Metamorphism and partial melting of ordinary chondrites: Calculated phase equilibria (United States)

    Johnson, T. E.; Benedix, G. K.; Bland, P. A.


    Constraining the metamorphic pressures (P) and temperatures (T) recorded by meteorites is key to understanding the size and thermal history of their asteroid parent bodies. New thermodynamic models calibrated to very low P for minerals and melt in terrestrial mantle peridotite permit quantitative investigation of high-T metamorphism in ordinary chondrites using phase equilibria modelling. Isochemical P-T phase diagrams based on the average composition of H, L and LL chondrite falls and contoured for the composition and abundance of olivine, ortho- and clinopyroxene, plagioclase and chromite provide a good match with values measured in so-called equilibrated (petrologic type 4-6) samples. Some compositional variables, in particular Al in orthopyroxene and Na in clinopyroxene, exhibit a strong pressure dependence when considered over a range of several kilobars, providing a means of recognising meteorites derived from the cores of asteroids with radii of several hundred kilometres, if such bodies existed at that time. At the low pressures (phase diagrams predict the onset of partial melting at 1050-1100 °C by incongruent reactions consuming plagioclase, clinopyroxene and orthopyroxene, whose compositions change abruptly as melting proceeds. These predictions match natural observations well and support the view that type 7 chondrites represent a suprasolidus continuation of the established petrologic types at the extremes of thermal metamorphism. The results suggest phase equilibria modelling has potential as a powerful quantitative tool in investigating, for example, progressive oxidation during metamorphism, the degree of melting and melt loss or accumulation required to produce the spectrum of differentiated meteorites, and whether the onion shell or rubble pile model best explains the metamorphic evolution of asteroid parent bodies in the early solar system.

  19. Model Microvascular Networks Can Have Many Equilibria. (United States)

    Karst, Nathaniel J; Geddes, John B; Carr, Russell T


    We show that large microvascular networks with realistic topologies, geometries, boundary conditions, and constitutive laws can exhibit many steady-state flow configurations. This is in direct contrast to most previous studies which have assumed, implicitly or explicitly, that a given network can only possess one equilibrium state. While our techniques are general and can be applied to any network, we focus on two distinct network types that model human tissues: perturbed honeycomb networks and random networks generated from Voronoi diagrams. We demonstrate that the disparity between observed and predicted flow directions reported in previous studies might be attributable to the presence of multiple equilibria. We show that the pathway effect, in which hematocrit is steadily increased along a series of diverging junctions, has important implications for equilibrium discovery, and that our estimates of the number of equilibria supported by these networks are conservative. If a more complete description of the plasma skimming effect that captures red blood cell allocation at junctions with high feed hematocrit were to be obtained empirically, then the number of equilibria found by our approach would at worst remain the same and would in all likelihood increase significantly.

  20. Algebraic geometrization of the Kuramoto model: Equilibria and stability analysis (United States)

    Mehta, Dhagash; Daleo, Noah S.; Dörfler, Florian; Hauenstein, Jonathan D.


    Finding equilibria of the finite size Kuramoto model amounts to solving a nonlinear system of equations, which is an important yet challenging problem. We translate this into an algebraic geometry problem and use numerical methods to find all of the equilibria for various choices of coupling constants K, natural frequencies, and on different graphs. We note that for even modest sizes (N ˜ 10-20), the number of equilibria is already more than 100 000. We analyze the stability of each computed equilibrium as well as the configuration of angles. Our exploration of the equilibrium landscape leads to unexpected and possibly surprising results including non-monotonicity in the number of equilibria, a predictable pattern in the indices of equilibria, counter-examples to conjectures, multi-stable equilibrium landscapes, scenarios with only unstable equilibria, and multiple distinct extrema in the stable equilibrium distribution as a function of the number of cycles in the graph.

  1. Uniqueness of Nash equilibria in a quantum Cournot duopoly game (United States)

    Sekiguchi, Yohei; Sakahara, Kiri; Sato, Takashi


    A quantum Cournot game whose classical form game has multiple Nash equilibria is examined. Although the classical equilibria fail to be Pareto optimal, the quantum equilibrium exhibits the following two properties: (i) if the measurement of entanglement between strategic variables chosen by the competing firms is sufficiently large, the multiplicity of equilibria vanishes, and (ii) the more strongly the strategic variables are entangled, the more closely the unique equilibrium approaches to the optimal one.

  2. Uniqueness of Nash equilibria in a quantum Cournot duopoly game

    Energy Technology Data Exchange (ETDEWEB)

    Sekiguchi, Yohei; Sakahara, Kiri; Sato, Takashi [Graduate School of Economics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan)], E-mail:, E-mail:, E-mail:


    A quantum Cournot game whose classical form game has multiple Nash equilibria is examined. Although the classical equilibria fail to be Pareto optimal, the quantum equilibrium exhibits the following two properties: (i) if the measurement of entanglement between strategic variables chosen by the competing firms is sufficiently large, the multiplicity of equilibria vanishes, and (ii) the more strongly the strategic variables are entangled, the more closely the unique equilibrium approaches to the optimal one.

  3. The responsiveness and correlation between Fugl-Meyer Assessment, Motor Status Scale, and the Action Research Arm Test in chronic stroke with upper-extremity rehabilitation robotic training. (United States)

    Wei, Xi-Jun; Tong, Kai-Yu; Hu, Xiao-Ling


    Responsiveness of clinical assessments is an important element in the report of clinical effectiveness after rehabilitation. The correlation could reflect the validity of assessments as an indication of clinical performance before and after interventions. This study investigated the correlation and responsiveness of Fugl-Meyer Assessment (FMA), Motor Status Scale (MSS), Action Research Arm Test (ARAT) and the Modified Ashworth Scale (MAS), which are used frequently in effectiveness studies of robotic upper-extremity training in stroke rehabilitation. Twenty-seven chronic stroke patients were recruited for a 20-session upper-extremity rehabilitation robotic training program. This was a rater-blinded randomized controlled trial. All participants were evaluated with FMA, MSS, ARAT, MAS, and Functional Independent Measure before and after robotic training. Spearman's rank correlation coefficient was applied for the analysis of correlation. The standardized response mean (SRM) and Guyatt's responsiveness index (GRI) were used to analyze responsiveness. Spearman's correlation coefficient showed a significantly high correlation (ρ=0.91-0.96) among FMA, MSS, and ARAT and a fair-to-moderate correlation (ρ=0.40-0.62) between MAS and the other assessments. FMA, MSS, and MAS on the wrist showed higher responsiveness (SRM=0.85-0.98, GRI=1.59-3.62), whereas ARAT showed relatively less responsiveness (SRM=0.22, GRI=0.81). The results showed that FMA or MSS would be the best choice for evaluating the functional improvement in stroke studies on robotic upper-extremity training with high responsiveness and good correlation with ARAT. MAS could be used separately to evaluate the spasticity changes after intervention in terms of high responsiveness.

  4. The correlation between stabbing-related upper extremity wounds and survival of stabbing victims with abdominal and thoracic injuries. (United States)

    Rozenfeld, Michael; Peleg, Kobi; Givon, Adi; Kessel, Boris


    When treating patients with stab injuries of the torso, clinicians often lack timely information about the degree and nature of internal organ damage. An externally observable sign significantly associated with characteristics of torso injuries may therefore be useful for practitioners. One such potential sign is the presence of wounds to the hands, sometimes sustained during victims' attempt to defend themselves during the violent altercation. Thus, the primary aim of this study was to evaluate the association between presence of upper extremity wounds and the severity of the thoracic and intra-abdominal injuries due to stabbing. This study was carried out retrospectively using data on 8714 patients with stabbing-related injuries from 19 trauma centers that participated in the Israeli National Trauma Registry (INTR) between January 1st1997 and December 31st 2013. Patients with wounds of upper extremities in addition to torso injuries (UE group) were compared to other patients with torso injuries (TO group) in terms of demographics, injury characteristics and clinical outcome. The compared groups were found to be homogeneous in terms of age and systolic blood pressure; the number of sustained torso injuries was also identical. The UE group comprised a slightly greater percentage of females, however both groups were predominantly male. Patients with upper extremity injuries had a lower proportion of internal organ damage (36% vs. 38.5%) and lower mortality (0.9% vs. 2%). The higher mortality of patients without upper extremity wounds remained significantly different even when adjusted by other epidemiological parameters (OR 2.46, 95% CI 1.33-5.08).The number of sustained upper extremity injuries was positively associated with deeper penetration of the torso by the stabbing instrument. Patients with stabbing-related upper extremity wounds had a significant survival advantage over patients without such injuries. However, a greater number of sustained upper extremity

  5. Neutral and stable equilibria of genetic systems and the hardy-weinberg principle: limitations of the chi-square test and advantages of auto-correlation functions of allele frequencies. (United States)

    Bosco, Francisco; Castro, Diogo; Briones, Marcelo R S


    Since the foundations of Population Genetics the notion of genetic equilibrium (in close analogy with Classical Mechanics) has been associated with the Hardy-Weinberg (HW) principle and the identification of equilibrium is currently assumed by stating that the HW axioms are valid if appropriate values of χ(2) (p test is not decisive and may lead to false negatives in random mating populations and false positives in non-random mating populations. This result confirms the logical statement that statistical tests cannot be used to deduce if the genetic population is under the HW conditions. Furthermore, we show that under the HW conditions populations of any size evolve in time according to what can be identified as neutral dynamics to which the very notion of equilibrium is unattainable for any practical purpose. Therefore, under the HW conditions the identification of equilibrium properties needs a different approach and the use of more appropriate concepts. We also show that by relaxing the condition of random mating the dynamics acquires all the characteristics of asymptotic stable equilibrium. As a consequence our results show that the question of equilibrium in genetic systems should be approached in close analogy to non-equilibrium statistical physics and its observability should be focused on dynamical quantities like the typical decay properties of the allelic auto-correlation function in time. In this perspective one should abandon the classical notion of genetic equilibrium and its relation to the HW proportions and open investigations in the direction of searching for unifying general principles of population genetic transformations capable to take in consideration these systems in their full complexity.

  6. Neutral and Stable Equilibria of Genetic Systems and The Hardy-Weinberg Principle: Limitations of the Chi-Square Test and Advantages of Auto-Correlation Functions of Allele Frequencies

    Directory of Open Access Journals (Sweden)

    Francisco A Bosco


    Full Text Available Since the foundations of Population Genetics the notion of genetic equilibrium (in close analogy to Classical Mechanics has been associated with the Hardy-Weinberg (HW Principle and the identification of equilibrium is currently assumed by stating that the HW axioms are valid if appropriate values of Chi-Square (p<0.05 are observed in experiments. Here we show by numerical experiments with the genetic system of one locus/two alleles that considering large ensembles of populations the Chi-Square test is not decisive and may lead to false negatives in random mating populations and false positives in nonrandom mating populations. This result confirms the logical statement that statistical tests cannot be used to deduce if the genetic population is under the HW conditions. Furthermore, we show that under the HW conditions populations of any size evolve in time according to what can be identified as neutral dynamics to which the very notion of equilibrium is unattainable for any practical purpose. Therefore, under the HW conditions the identification of equilibrium properties needs a different approach and the use of more appropriate concepts. We also show that by relaxing the condition of random mating the dynamics acquires all the characteristics of asymptotic stable equilibrium. As a consequence our results show that the question of equilibrium in genetic systems should be approached in close analogy to non-equilibrium statistical physics and its observability should be focused on dynamical quantities like the typical decay properties of the allelic auto correlation function in time. In this perspective one should abandon the classical notion of genetic equilibrium and its relation to the HW proportions and open investigations in the direction of searching for unifying general principles of population genetic transformations capable to take in consideration these systems in their full complexity.

  7. Liquid-liquid equilibria of the ternary system thiophene + octane + dimethyl sulfoxide at several temperatures. (United States)

    Zhang, Wenlin; Hou, Kaihu; Mi, Guanjie; Chen, Na


    Liquid-liquid equilibria (LLE) data of the ternary system thiophene + octane + dimethyl sulfoxide at 40 degrees C, 50 degrees C, and 60 degrees C under atmospheric pressure were determined using an equilibrium cell with the standard curve method. The distribution of thiophene between extract and raffinate was measured and a practical formula of equilibria data for industrial extraction was proposed. NRTL model and UNIQUAC model were used to correlate and calculate LLE data of the system, and model parameters were determined using the simplex optimization method and imitative Newton method with a minimized objective function of mole fraction deviation. The rule of thermodynamic equilibria was used to deal with multi-roots problem in correlating process. Agreement between predicted and experimental data was satisfactory. The average absolute deviations of the NRTL and UNIQUAC models of thiophene mass fraction were 0.0040 and 0.0078, respectively. Both NRTL and UNIQUAC models were suitable for the calculation of LLE data of the ternary system thiophene + octane + dimethyl sulfoxide. The correlation accuracy of NRTL model is inferior to that of UNIQUAC model.

  8. High temperature phase equilibria and phase diagrams

    CERN Document Server

    Kuo, Chu-Kun; Yan, Dong-Sheng


    High temperature phase equilibria studies play an increasingly important role in materials science and engineering. It is especially significant in the research into the properties of the material and the ways in which they can be improved. This is achieved by observing equilibrium and by examining the phase relationships at high temperature. The study of high temperature phase diagrams of nonmetallic systems began in the early 1900s when silica and mineral systems containing silica were focussed upon. Since then technical ceramics emerged and more emphasis has been placed on high temperature

  9. Cycles and Multiple Equilibria in the Market for Durable Lemons

    NARCIS (Netherlands)

    M.C.W. Janssen (Maarten); V.A. Karamychev (Vladimir)


    textabstractWe investigate the nature of market failure in a dynamic version of Akerlof (1970) where identical cohorts of a durable good enter the market over time. In the dynamic model, equilibria with qualitatively different properties emerge. Typically, in equilibria of the dynamic model, sellers

  10. Excisional biopsy of suspected benign soft tissue tumors of the upper extremity: correlation between preoperative diagnosis and actual pathology

    NARCIS (Netherlands)

    Sluijmer, Heleen C. E.; Becker, Stéphanie J. E.; Bossen, Jeroen K. J.; Ring, David


    Tumors of the upper extremity are common and mostly benign. However, the prevalence of discordant diagnosis of a solid hand tumor is less studied. The objectives of this retrospective study were (1) to determine the proportion of patients with a different (discrepant or discordant) pathological

  11. Classification of lower extremity movement patterns based on visual assessment: reliability and correlation with 2-dimensional video analysis. (United States)

    Harris-Hayes, Marcie; Steger-May, Karen; Koh, Christine; Royer, Nat K; Graci, Valentina; Salsich, Gretchen B


    Abnormal movement patterns have been implicated in lower extremity injury. Reliable, valid, and easily implemented assessment methods are needed to examine existing musculoskeletal disorders and investigate predictive factors for lower extremity injury. To determine the reliability of experienced and novice testers in making visual assessments of lower extremity movement patterns and to characterize the construct validity of the visual assessments. Cross-sectional study. University athletic department and research laboratory. Convenience sample of 30 undergraduate and graduate students who regularly participate in athletics (age = 19.3 ± 4.5 years). Testers were 2 experienced physical therapists and 1 novice postdoctoral fellow (nonclinician). We took videos of 30 athletes performing the single-legged squat. Three testers observed the videos on 2 occasions and classified the lower extremity movement as dynamic valgus, no change, or dynamic varus. The classification was based on the estimated change in frontal-plane projection angle (FPPA) of the knee from single-legged stance to maximum single-legged squat depth. The actual FPPA change was measured quantitatively. We used percentage agreement and weighted κ to examine tester reliability and to determine construct validity of the visual assessment. The κ values for intratester and intertester reliability ranged from 0.75 to 0.90, indicating substantial to excellent reliability. Percentage agreement between the visual assessment and the quantitative FPPA change category was 90%, with a κ value of 0.85. Visual assessments were made reliably by experienced and novice testers. Additionally, movement-pattern categories based on visual assessments were in excellent agreement with objective methods to measure FPPA change. Therefore, visual assessments can be used in the clinic to assess movement patterns associated with musculoskeletal disorders and in large epidemiologic studies to assess the association between lower

  12. New investigation of phase equilibria in the system Al-Cu-Si

    Energy Technology Data Exchange (ETDEWEB)

    Ponweiser, Norbert [University of Vienna, Department of Inorganic Chemistry/Materials Chemistry, Waehringer Strasse 42, 1090 Wien (Austria); Richter, Klaus W., E-mail: [University of Vienna, Department of Inorganic Chemistry/Materials Chemistry, Waehringer Strasse 42, 1090 Wien (Austria)


    Highlights: Black-Right-Pointing-Pointer Isothermal sections at 500 and 700 Degree-Sign C investigated. Black-Right-Pointing-Pointer Vertical sections (partial at 10 at.% Si, complete at 40 at.% Si) determined. Black-Right-Pointing-Pointer Partial ternary reaction scheme (Scheil diagram) established. Black-Right-Pointing-Pointer New ternary compound identified. - Abstract: The phase equilibria and invariant reactions in the system Al-Cu-Si were investigated by a combination of optical microscopy, powder X-ray diffraction (XRD), differential thermal analysis (DTA) and electron probe micro analysis (EPMA). Isothermal phase equilibria were investigated within two isothermal sections. The isothermal section at 500 Degree-Sign C covers the whole ternary composition range and largely confirms the findings of previous phase diagram investigations. The isothermal section at 700 Degree-Sign C describes phase equilibria only in the complex Cu-rich part of the phase diagram. A new ternary compound {tau} was found in the region between (Al,Cu)-{gamma}{sub 1} and (Cu,Si)-{gamma} and its solubility range was determined. The solubility of Al in {kappa}-CuSi was found to be extremely high at 700 Degree-Sign C. In contrast, no ternary solubility in the {beta}-phase of Cu-Al was found, although this phase is supposed to form a complete solid solution according to previous phase diagram assessments. Two isopleths, at 10 and 40 at.% Si, were investigated by means of DTA and a partial ternary reaction scheme (Scheil diagram) was constructed, based on the current work and the latest findings in the binary systems Al-Cu and Cu-Si. The current study shows that the high temperature equilibria in the Cu-rich corner are still poorly understood and additional studies in this area would be favorable.

  13. Plasma Equilibria With Stochastic Magnetic Fields (United States)

    Krommes, J. A.; Reiman, A. H.


    Plasma equilibria that include regions of stochastic magnetic fields are of interest in a variety of applications, including tokamaks with ergodic limiters and high-pressure stellarators. Such equilibria are examined theoretically, and a numerical algorithm for their construction is described.^2,3 % The balance between stochastic diffusion of magnetic lines and small effects^2 omitted from the simplest MHD description can support pressure and current profiles that need not be flattened in stochastic regions. The diffusion can be described analytically by renormalizing stochastic Langevin equations for pressure and parallel current j, with particular attention being paid to the satisfaction of the periodicity constraints in toroidal configurations with sheared magnetic fields. The equilibrium field configuration can then be constructed by coupling the prediction for j to Amp'ere's law, which is solved numerically. A. Reiman et al., Pressure-induced breaking of equilibrium flux surfaces in the W7AS stellarator, Nucl. Fusion 47, 572--8 (2007). J. A. Krommes and A. H. Reiman, Plasma equilibrium in a magnetic field with stochastic regions, submitted to Phys. Plasmas. J. A. Krommes, Fundamental statistical theories of plasma turbulence in magnetic fields, Phys. Reports 360, 1--351.


    Energy Technology Data Exchange (ETDEWEB)

    CHU, M.S.; PARKS, P.B.


    OAK B202 TOKAMAK EQUILIBRIA WITH CENTRAL CURRENT HOLES AND NEGATIVE CURRENT DRIVE. Several tokamak experiments have reported the development of a central region with vanishing currents (the current hole). Straightforward application of results from the work of Greene, Johnson and Weimer [Phys. Fluids, 3, 67 (1971)] on tokamak equilibrium to these plasmas leads to apparent singularities in several physical quantities including the Shafranov shift and casts doubts on the existence of this type of equilibria. In this paper, the above quoted equilibrium theory is re-examined and extended to include equilibria with a current hole. It is shown that singularities can be circumvented and that equilibria with a central current hole do satisfy the magnetohydrodynamic equilibrium condition with regular behavior for all the physical quantities and do not lead to infinitely large Shafranov shifts. Isolated equilibria with negative current in the central region could exist. But equilibria with negative currents in general do not have neighboring equilibria and thus cannot have experimental realization, i.e. no negative currents can be driven in the central region.

  15. Liquid-liquid equilibria for ternary polymer mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Suk Yung [Division of Chemical Engineering and Molecular Thermodynamics Laboratory, Hanyang University, Seoul 133-791 (Korea, Republic of); Bae, Young Chan, E-mail: [Division of Chemical Engineering and Molecular Thermodynamics Laboratory, Hanyang University, Seoul 133-791 (Korea, Republic of)


    Graphical abstract: We developed a molecular thermodynamic model for multicomponent systems and discribed the phase equilibrium for ternary polymer mixtures by using the model parameters obtained from the binary systems. Research highlights: {yields} Model parameters were obtained from the binary systems. {yields} The obtained parameters were directly used to predict the ternary data. {yields} The undetermined parameters were used to correlate the ternary data. {yields} The proposed model agreed well with the experimental data. - Abstract: A molecular thermodynamic model for multicomponent systems based on a closed-packed lattice model is presented based on two contributions; entropy and energy contribution. The calculated liquid-liquid equilibria of ternary chainlike mixtures agreed with Monte Carlo simulation results. The proposed model can satisfactorily predict Types 0, 1, 2 and 3 phase separations of the Treybal classification. The model parameters obtained from the binary systems were used to directly predict real ternary systems and the calculated results correlated well with experimental data using few adjustable parameters. Specific interactions in associated binary systems were considered using a secondary lattice.

  16. Close pairs of relative equilibria for identical point vortices

    DEFF Research Database (Denmark)

    Dirksen, Tobias; Aref, Hassan


    Numerical solution of the classical problem of relative equilibria for identical point vortices on the unbounded plane reveals configurations that are very close to the analytically known, centered, symmetrically arranged, nested equilateral triangles. New numerical solutions of this kind are found...... also has this property, and new relative equilibria close to the nested, symmetrically arranged, regular heptagons have been found. The centered regular nonagon is also marginally stable. Again, a new family of close relative equilibria has been found. The closest relative equilibrium pairs occur...

  17. Liquid-liquid equilibria for binary and ternary polymer solutions with PC-SAFT

    DEFF Research Database (Denmark)

    Lindvig, Thomas; Michelsen, Michael Locht; Kontogeorgis, Georgios


    are used for investigating the correlative and predictive capabilities of the thermodynamic model PC-SAFT. The investigation shows that the model correlates well experimental LLE data for binary as well as ternary systems but further predicts the behavior of the ternary systems with reasonably good......Two algorithms for evaluating liquid-liquid equilibria (LLE) for binary and ternary polymer solutions are presented. The binary algorithm provides the temperature versus concentration cloud-point curve at fixed pressure, whereas the ternary algorithm provides component 1 versus component 2...

  18. Ternary liquid-liquid equilibria measurement for epoxidized soybean oil + acetic acid + water. (United States)

    Cai, Shuang-Fei; Wang, Li-Sheng; Yan, Guo-Qing; Li, Yi; Feng, Yun-Xia; Linghu, Rong-Gang


    Liquid-liquid equilibria (LLE) data were measured for ternary system epoxidized soybean oil (ESO) + acetic acid + water at 313.15, 323.15 and 333.15 K, respectively. The consistency of the measured LLE data was tested, using Othmer-Tobias correlation and root-mean-square deviation (sigma) in mass fraction of water in the lower phase and average value of the absolute difference (AAD) between experimental mass fraction of epoxidized soybean oil in the upper phase and that calculated using Othmer-Tobias correlation.

  19. MR imaging findings of high-voltage electrical burns in the upper extremities: correlation with angiographic findings

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Gyung Kyu; Kang, Ik Won; Hwang, Dae Hyun; Min, Seon Jung; Han, You Mi (Dept. of Radiology, Hallym Univ. College of Medicine, Hangang Sacred Heart Hospital, Seoul (Korea, Republic of)); Suh, Kyung Jin (Dept. of Radiology, Dongguk Univ. College of Medicine, Gyeongju Hospital, Gyeongju (Korea, Republic of)), email:; Choi, Min Ho (Dept. of Internal Medicine, Hallym Univ. College of Medicine, Hangang Sacred Heart Hospital, Seoul (Korea, Republic of))


    Background: A high-voltage electrical burn is often associated with deep muscle injuries. Hidden, undetected deep muscle injuries have a tendency for progressive tissue necrosis, and this can lead to major amputations or sepsis. MRI has excellent soft tissue contrast and it may aid in differentiating the areas of viable deep muscle from the areas of non-viable deep muscle. Purpose: To describe the MR imaging findings of a high-voltage electrical burn in the upper extremity with emphasis on the usefulness of the gadolinium-enhanced MRI and to compare the MR imaging findings with angiography. Material and Methods: We retrospectively reviewed the imaging studies of six patients with high-voltage electrical burns who underwent both MRI and angiography at the burn center of our hospital from January 2005 to December 2009. The imaging features were evaluated for the involved locations, the MR signal intensity of the affected muscles, the MR enhancement pattern, the involved arteries and the angiographic findings (classified as normal, sluggish flow, stenosis or occlusion) of the angiography of the upper extremity. We assessed the relationship between the MR imaging findings and the angiographic findings. Results: The signal intensities of affected muscles were isointense or of slightly high signal intensity as compared with the adjacent unaffected skeletal muscle on the T1-weighted MR images. Affected muscles showed heterogenous high signal intensity relative to the adjacent unaffected skeletal muscle on the T2- weighted images. The gadolinium-enhanced T1-weighted images showed diffuse inhomogeneous enhancement or peripheral rim enhancement of the affected muscles. The angiographic findings of the arterial injuries showed complete occlusion in three patients, severe stenosis in two patients and sluggish flow in one patient. Of these, the five patients with complete occlusion or severe stenosis on angiography showed non-perfused and non-viable areas of edematous muscle on

  20. Correlation between extreme fear and focal cortical dysplasia in anterior cingulate gyrus: Evidence from a surgical case of refractory epilepsy. (United States)

    Qiao, Liang; Yu, Tao; Ni, Duanyu; Wang, Xueyuan; Xu, Cuiping; Liu, Chang; Zhang, Guojun; Li, Yongjie


    Localizing the semiology of ictal fear and seizure onset in epilepsy patients is commonly challenging due to limited value of routine electroencephalography (EEG) and very few surgical attempts. Here we reported a case of refractory epilepsy characterized by aura of extreme fear and hypermotor seizures, in which the left (dominant hemisphere) anterior cingulate gyrus (ACG) was determined to be the epileptogenic zone (EZ) through multiple modalities of presurgical evaluation including analysis of high frequency oscillation on intracranial EEG. Tailored resection of EZ was thus performed and pathological examination revealed focal cortical dysplasia (FCD) type IIb. The patient has been seizure free during an 18-month follow-up. The report has provided novel anatomical, electrophysiological and surgical evidences suggesting the critical role of ACG in ictal fear and possibility of surgical management of fear-manifesting refractory epilepsy. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Mixed Nash equilibria in Eisert-Lewenstein-Wilkens (ELW) games (United States)

    Bolonek-Lasoń, Katarzyna; Kosiński, Piotr


    The classification of all mixed Nash equilibria for the original ELW game is presented. It is based on the quaternionic form of the game proposed by Landsburg (Proc. Am. Math. Soc. 139 (2011), 4423; Rochester Working Paper No 524 (2006); Wiley Encyclopedia of Operations Research and Management Science (Wiley and Sons, New York, (2011)). This approach allows to reduce the problem of finding the Nash equilibria to relatively simple analysis of the extrema of certain quadratic forms.

  2. Relevance of the correlation between precipitation and the 0 °C isothermal altitude for extreme flood estimation (United States)

    Zeimetz, Fraenz; Schaefli, Bettina; Artigue, Guillaume; García Hernández, Javier; Schleiss, Anton J.


    Extreme floods are commonly estimated with the help of design storms and hydrological models. In this paper, we propose a new method to take into account the relationship between precipitation intensity (P) and air temperature (T) to account for potential snow accumulation and melt processes during the elaboration of design storms. The proposed method is based on a detailed analysis of this P-T relationship in the Swiss Alps. The region, no upper precipitation intensity limit is detectable for increasing temperature. However, a relationship between the highest measured temperature before a precipitation event and the duration of the subsequent event could be identified. An explanation for this relationship is proposed here based on the temperature gradient measured before the precipitation events. The relevance of these results is discussed for an example of Probable Maximum Precipitation-Probable Maximum Flood (PMP-PMF) estimation for the high mountainous Mattmark dam catchment in the Swiss Alps. The proposed method to associate a critical air temperature to a PMP is easily transposable to similar alpine settings where meteorological soundings as well as ground temperature and precipitation measurements are available. In the future, the analyses presented here might be further refined by distinguishing between precipitation event types (frontal versus orographic).

  3. Thermodynamic Equilibria and Extrema Analysis of Attainability Regions and Partial Equilibria

    CERN Document Server

    Gorban, Alexander N; Kaganovich, Boris M; Keiko, Alexandre V; Shamansky, Vitaly A; Shirkalin, Igor A


    This book discusses mathematical models that are based on the concepts of classical equilibrium thermodynamics. They are intended for the analysis of possible results of diverse natural and production processes. Unlike the traditional models, these allow one to view the achievable set of partial equilibria with regards to constraints on kinetics, energy and mass exchange and to determine states of the studied systems of interest for the researcher. Application of the suggested models in chemical technology, energy and ecology is illustrated in the examples.

  4. Bilinear Relative Equilibria of Identical Point Vortices

    DEFF Research Database (Denmark)

    Aref, H.; Beelen, Peter; Brøns, Morten


    . In particular, we show that, given q(z)=z 2+η 2, where η is real, there is a unique p(z) of degree n, and a unique value of η 2=A n , such that the zeros of q(z) and p(z) form a relative equilibrium of n+2 point vortices. We show that $A_{n} \\approx\\frac{2}{3}n + \\frac{1}{2}$, as n→∞, where the coefficient of n......A new class of bilinear relative equilibria of identical point vortices in which the vortices are constrained to be on two perpendicular lines, conveniently taken to be the x- and y-axes of a Cartesian coordinate system, is introduced and studied. In the general problem we have m vortices on the y......, obtained using Sturm’s comparison theorem, is that if p(z) satisfies the ODE for a given q(z) with its imaginary zeros symmetric relative to the x-axis, then it must have at least n−m+2 simple, real zeros. For m=2 this provides a complete characterization of all zeros, and we study this case in some detail...

  5. Lower extremity flexibility patterns in classical ballet dancers and their correlation to lateral hip and knee injuries. (United States)

    Reid, D C; Burnham, R S; Saboe, L A; Kushner, S F


    Knee and hip problems account for up to 40% of injuries in classical ballet. Despite apparent flexibility, many dancers appeared to have tight iliotibial bands that contributed to lower limb problems. Thirty senior female ballet dancers were contrasted with thirty age-matched active volunteers for hip and knee range of motion, and the information derived was correlated with their orthopaedic medical histories. Dancers spent a reasonable period of time warming up, but it was usually with an unbalanced routine that emphasized hip abduction and external rotation to the exclusion of adduction work. This was reflected in the significantly lower range of passive hip adduction and internal rotation compared to the controls. Furthermore, the older and more experienced the dancer, the more this trend was exaggerated. This unbalanced flexibility may play a role in the production of lateral knee pain (30% of the dancers) and anterior hip pain (33% of the dancers). It is suggested that more attention should be given to a balanced stretching regimen as part of the dancers' warmup in an effort to reduce the frequency of some of the chronic hip and knee complaints.

  6. Identification of the non-stationarity of extreme precipitation events and correlations with large-scale ocean-atmospheric circulation patterns: A case study in the Wei River Basin, China (United States)

    Liu, Saiyan; Huang, Shengzhi; Huang, Qiang; Xie, Yangyang; Leng, Guoyong; Luan, Jinkai; Song, Xiaoyu; Wei, Xiu; Li, Xiangyang


    The investigation of extreme precipitation events in terms of variation characteristics, stationarity, and their underlying causes is of great significance to better understand the regional response of the precipitation variability to global climate change. In this study, the Wei River Basin (WRB), a typical eco-environmentally vulnerable region of the Loess Plateau in China was selected as the study region. A set of precipitation indices was adopted to study the changing patterns of precipitation extremes and the stationarity of extreme precipitation events. Furthermore, the correlations between the Pacific Decadal Oscillation (PDO)/El Niño-Southern Oscillation (ENSO) events and precipitation extremes were explored using the cross wavelet technique. The results indicate that: (1) extreme precipitation events in the WRB are characterized by a significant decrease of consecutive wet days (CWD) at the 95% confidence level; (2) compared with annual precipitation, daily precipitation extremes are much more sensitive to changing environments, and the assumption of stationarity of extreme precipitation in the WRB is invalid, especially in the upstream, thereby introducing large uncertainty to the design and management of water conservancy engineering; (3) both PDO and ENSO events have a strong influence on precipitation extremes in the WRB. These findings highlight the importance of examining the validity of the stationarity assumption in extreme hydrological frequency analysis, which has great implications for the prediction of extreme hydrological events.

  7. The Correlations between Extremity Circumferences with Total and Regional Amounts of Skeletal Muscle and Muscle Strength in Obese Women with Type 2 Diabetes

    Directory of Open Access Journals (Sweden)

    Hwi Ryun Kwon


    Full Text Available BackgroundInsulin resistance is related to central obesity and the amount of skeletal muscle. A simple and practical anthropometric marker for muscle mass is not known, although waist circumference (WC is used as an indicator of abdominal obesity. The aims of this study were to investigate whether arm (AC and thigh circumferences (TC can be used as an indicator of muscle mass and if they are related to muscle strength.MethodsA total of 110 obese (body mass index [BMI]≥25 kg/m2 women with type 2 diabetes were enrolled, and WC, AC, and TC were measured. Abdominal visceral fat (AVF, subcutaneous fat (ASF, and total fat (ATF were assessed by computed tomography, regional muscle (MM, and fat mass by dual-energy X-ray absorptiometry, muscle strength by one repetition maximum (1RM of both extremities (chest and leg press and insulin resistance by KITT.ResultsThe mean age was 56.2±7.3 years, duration of diabetes was 4.2±4.4 years, and BMI was 27.2±2.8 kg/m2. WC was correlated with ATF, AVF, and ASF (r=0.728, P<0.001; r=0.515, P<0.001; r=0.608, P<0.001, respectively. Arm MM was correlated with AC (r=0.500, P<0.001, and leg MM with TC (r=0.291, P=0.002. Upper 1RM was related to AC/WC ratio (r=0.359, P<0.001, and lower 1RM was to TC/WC ratio (r=0.286, P=0.003. Insulin resistance had significant relations with AVF, WC, and total MM (r=-0.262, P=0.008; r=-0.217, P=0.029; r=0.160, P=0.031, respectively.ConclusionThe muscle mass was related to extremity circumferences, and muscle strength was to extremity/waist circumference ratio in obese women with type 2 diabetes.

  8. Measurement and modeling of high-pressure (vapor + liquid) equilibria of (CO{sub 2} + alkanol) binary systems

    Energy Technology Data Exchange (ETDEWEB)

    Bejarano, Arturo; Gutierrez, Jorge E. [Departamento de Ingenieria Quimica y Ambiental, Universidad Tecnica Federico Santa Maria, Avda. Espana 1680, Valparaiso (Chile); Araus, Karina A. [Departamento de Ingenieria Quimica y Bioprocesos, Pontificia Universidad Catolica de Chile, Avda. Vicuna Mackenna 4860, Macul, Santiago (Chile); Fuente, Juan C. de la, E-mail: juan.delafuente@usm.c [Departamento de Ingenieria Quimica y Ambiental, Universidad Tecnica Federico Santa Maria, Avda. Espana 1680, Valparaiso (Chile); Centro Regional de Estudios en Alimentos Saludables, Blanco 1623, Valparaiso (Chile)


    Research highlights: (Vapor + liquid) equilibria of three (CO{sub 2} + C{sub 5} alcohol) binary systems were measured. Complementary data are reported at (313, 323 and 333) K and from (2 to 11) MPa. No liquid immiscibility was observed at the temperatures and pressures studied. Experimental data were correlated with the PR-EoS and the van de Waals mixing rules. Correlation results showed relative deviations {<=}8 % (liquid) and {<=}2 % (vapor). - Abstract: Complementary isothermal (vapor + liquid) equilibria data are reported for the (CO{sub 2} + 3-methyl-2-butanol), (CO{sub 2} + 2-pentanol), and (CO{sub 2} + 3-pentanol) binary systems at temperatures of (313, 323, and 333) K, and at pressure range of (2 to 11) MPa. For all (CO{sub 2} + alcohol) systems, it was visually monitored that there was no liquid immiscibility at the temperatures and pressures studied. The experimental data were correlated with the Peng-Robinson equation of state using the quadratic mixing rules of van der Waals with two adjustable parameters. The calculated (vapor + liquid) equilibria compositions were found to be in good agreement with the experimental data with deviations for the mole fractions <8% and <2% for the liquid and vapor phase, respectively.

  9. Nash Equilibria in Symmetric Games with Partial Observation

    DEFF Research Database (Denmark)

    Bouyer, Patricia; Markey, Nicolas; Vester, Steen


    We investigate a model for representing large multiplayer games, which satisfy strong symmetry properties. This model is made of multiple copies of an arena; each player plays in his own arena, and can partially observe what the other players do. Therefore, this game has partial information...... and symmetry constraints, which make the computation of Nash equilibria difficult. We show several undecidability results, and for bounded-memory strategies, we precisely characterize the complexity of computing pure Nash equilibria (for qualitative objectives) in this game model....

  10. Nash Equilibria in Symmetric Graph Games with Partial Observation

    DEFF Research Database (Denmark)

    Bouyer, Patricia; Markey, Nicolas; Vester, Steen


    We investigate a model for representing large multiplayer games, which satisfy strong symmetry properties. This model is made of multiple copies of an arena; each player plays in his own arena, and can partially observe what the other players do. Therefore, this game has partial information...... and symmetry constraints, which make the computation of Nash equilibria difficult. We show several undecidability results, and for bounded-memory strategies, we precisely characterize the complexity of computing pure Nash equilibria for qualitative objectives in this game model....

  11. A method of computational magnetohydrodynamics defining stable Scyllac equilibria (United States)

    Betancourt, Octavio; Garabedian, Paul


    A computer code has been developed for the numerical calculation of sharp boundary equilibria of a toroidal plasma with diffuse pressure profile. This generalizes earlier work that was done separately on the sharp boundary and diffuse models, and it allows for large amplitude distortions of the plasma in three-dimensional space. By running the code, equilibria that are stable to the so-called m = 1, k = 0 mode have been found for Scyllac, which is a high beta toroidal confinement device of very large aspect ratio. PMID:16592383

  12. Evaluation of a Mathematical Model for Single Component Adsorption Equilibria with Reference to the Prediction of Multicomponent Adsorption Equilibria

    DEFF Research Database (Denmark)

    Krøll, Annette Elisabeth; Marcussen, Lis


    An equilibrium equation for pure component adsorption is compared to experiments and to the vacancy solution theory. The investigated equilibrium equation is a special case of a model for prediction of multicomponent adsorption equilibria.The vacancy solution theory for multicomponent systems...... requires binary experimental data for determining the interaction parameters of the Wilson equation; thus a large number of experiments are needed. The multicomponent equilibria model which is investigated for single component systems in this work is based on pure component data only. This means...... that the requirement for experimental data is reduced significantly.The two adsorption models are compared, using experimental pure gas adsorption data found in literature. The results obtained by the models are in close agreement for pure component equilibria and they give a good description of the experimental data...

  13. Genome flux in tomato cell clones cultured in vitro in different physiological equilibria. II. A RAPD analysis of variability. (United States)

    Bogani, P; Simoni, A; Lio', P; Scialpi, A; Buiatti, M


    An analysis of the effect of changing physiological conditions on genome evolution in tomato cell populations has been carried out on long-term in vitro cultured clones grown on different auxin-cytokinin equilibria or selected for low-high competence for active defense against Fusarium oxysporum f.sp. lycopersici. RAPD analysis, confirmed through pattern rehybridization, was used as a random tool to measure the genetic variability. Through the use of a modified ANOVA, variation was shown to depend on both the initial genotype and the physiological conditions. Pattern correlation analysis through a mutual information algorithm suggested the fixation of RAPD patterns specific to physiological equilibria. The results are discussed in view of the possible relevance for evolution at hierarchical levels higher than cell populations. Key words : tomato clones, somaclonal variation, RAPD, coadaptation.

  14. Experimental investigation of phase equilibria in the Nb-Si-Ta ternary system

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jian; Wang, Cuiping; Yao, Jun; Yang, Shuiyuan; Zhan Shi; Liu, Xingjun [Xiamen Univ. (China). Dept. of Materials Science and Engineering; Xiamen Univ. (China). Fujian Provincial Key Laboratory of Materials Genome; Kang, Yongwang [Beijing Institute of Aeronautical Materials (China). Science and Technology on Advanced High Temperature Structural Materials Lab.


    The phase equilibria in the Nb-Si-Ta ternary system at 1 373 K, 1 473 K and 1 573 K were investigated by means of back-scattered electron imaging, electron probe microanalysis and X-ray diffraction. The isothermal sections at 1 373 K, 1 473 K and 1 573 K consist of two three-phase regions and seven two-phase regions, without any ternary compounds. The compounds of NbSi{sub 2} and TaSi{sub 2}, αNb{sub 5}Si{sub 3} and αTa{sub 5}Si{sub 3} form continuous solid solutions, respectively. The solubilities of Nb in Ta{sub 3}Si and Ta{sub 2}Si phases are extremely large, whereas the solubility of Si in the β(Nb, Ta) phase is relatively small.

  15. The Quality of Equilibria for Set Packing Games

    NARCIS (Netherlands)

    Jong, Jasper de; Uetz, Marc


    We introduce set packing games as an abstraction of situations in which $n$ selfish players select subsets of a finite set of indivisible items, and analyze the quality of several equilibria for this class of games. Assuming that players are able to approximately play equilibrium strategies, we show

  16. Coordination equilibria in the complex formation of guanylurea with ...

    Indian Academy of Sciences (India)


    calculating the equilibrium constants using the com- puter program SCOGS,9 run on a Pentium-4 com- puter. Refined values of the constants (table 1) corresponding to the minimum standard deviations were accepted for calculating the speciation curves. (figures 2, 3), required for elucidation of the com- plexation equilibria.

  17. High-pressure, flux-conserving tokamak equilibria

    Energy Technology Data Exchange (ETDEWEB)

    Dory, R.A.; Peng, Y.K.M.


    Magnetohydrodynamic (MHD) tokamak equilibria are found with values of ..beta.. up to 20 percent and prescribed MHD safety factor values (e.g., q(axis) = 1 and q(edge) = 4.8) for tokamaks with aspect ratio A = 4 and D-shaped cross section. If such equilibria could be attained experimentally, they would be very attractive for decreasing the projected costs of tokamak power reactors substantially. In the flux-conserving tokamak (FCT) model, where rapid heating is applied to an already relatively hot plasma, these high ..beta.. equilibria are achievable. We study the quasi-static evolution of FCT equilibria as ..beta.. increases. An operating window is found in the pressure profile width w/sub p/: for high ..beta.. the values of w/sub p/ must lie between 0.40 and 0.55 of the plasma minor width. Within this window, plasma current and poloidal ..beta.. increase monotonically with ..beta... For fixed plasma boundary, significant poloidal surface currents are induced, but these can be eliminated by small increases in the plasma minor radius, the pressure profile width, and the vacuum toroidal field.

  18. Computation of Stackelberg Equilibria of Finite Sequential Games

    DEFF Research Database (Denmark)

    Bosanski, Branislav; Branzei, Simina; Hansen, Kristoffer Arnsfelt


    The Stackelberg equilibrium is a solution concept that describes optimal strategies to commit to: Player~1 (the leader) first commits to a strategy that is publicly announced, then Player~2 (the follower) plays a best response to the leader's choice. We study Stackelberg equilibria in finite...

  19. From Singularity Theory to Finiteness of Walrasian Equilibria

    DEFF Research Database (Denmark)

    Castro, Sofia B.S.D.; Dakhlia, Sami F.; Gothen, Peter

    The paper establishes that for an open and dense subset of smooth exchange economies, the number of Walrasian equilibria is finite. In particular, our results extend to non-regular economies; it even holds when restricted to the subset of critical ones. The proof rests on concepts from singularity...

  20. Cryptographically Blinded Games: Leveraging Players' Limitations for Equilibria and Profit

    DEFF Research Database (Denmark)

    Hubacek, Pavel; Park, Sunoo


    In this work we apply methods from cryptography to enable mutually distrusting players to implement broad classes of mediated equilibria of strategic games without trusted mediation. Our implementation uses a pre-play 'cheap talk' phase, consisting of non- binding communication between players pr...

  1. Acid-Base and Precipitation Equilibria in Wine (United States)

    Palma, Miguel; Barroso, Carmelo G.


    Experiments are performed to establish the changes of pH during the precipitation of potassium hydrogen tartrate, with its unfavorable impact on the stability of wine. Students, thus, obtain a clearer understanding of the interplay between a variety of chemical equilibria within a single medium.

  2. Deep water periodic waves as Hamiltonian relative equilibria

    NARCIS (Netherlands)

    van Groesen, Embrecht W.C.; Lie She Liam, L.S.L.; Lakhturov, I.; Andonowati, A.; Biggs, N.


    We use a recently derived KdV-type of equation for waves on deep water to study Stokes waves as relative equilibria. Special attention is given to investigate the cornered Stokes-120 degree wave as a singular solution in the class of smooth steady wave profiles.

  3. Kinetics and equilibria for the axial ligation of bromomethyl (aqua ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences; Volume 121; Issue 6. Kinetics and equilibria for the axial ligation of bromomethyl (aqua)cobaloxime with pyridines - Isolation characterization and DNA binding. Kotha Laxma Reddy K Ashwini Kumar N Ravi Kumar Reddy Penumaka Nagababu A Panasa Reddy S ...

  4. Magnetic-surface quality in nonaxisymmetric plasma equilibria. (United States)

    Nührenberg, Carolin; Boozer, Allen H; Hudson, Stuart R


    The confinement of plasmas by magnetic fields with nonaxisymmetric shaping can be degraded or destroyed by the breakup of the magnetic surfaces through effects that are intrinsic to the shaping. An efficient perturbation method of determining this drive for islands was developed and applied to stellarator equilibria.

  5. Phase equilibria of didecyldimethylammonium nitrate ionic liquid with water and organic solvents

    Energy Technology Data Exchange (ETDEWEB)

    Domanska, Urszula [Physical Chemistry Division, Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw (Poland)]. E-mail:; Lugowska, Katarzyna [Physical Chemistry Division, Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw (Poland); Pernak, Juliusz [Faculty of Chemical Technology, Poznan University of Technology, Poznan (Poland)


    The phase diagrams for binary mixtures of an ammonium ionic liquid, didecyldimethylammonium nitrate, [DDA][NO{sub 3}], with: alcohols (propan-1-ol, butan-1-ol, octan-1-ol, and decan-1-ol): hydrocarbons (toluene, propylbenzene, hexane, and hexadecane) and with water were determined in our laboratory. The phase equilibria were measured by a dynamic method from T 220 K to either the melting point of the ionic liquid, or to the boiling point of the solvent. A simple liquidus curve in a eutectic system was observed for [DDA][NO{sub 3}] with: alcohols (propan-1-ol, butan-1-ol, and octan-1-ol); aromatic hydrocarbons (toluene and propylbenzene) and with water. (Solid + liquid) equilibria with immiscibility in the liquid phase were detected with the aliphatic hydrocarbons heptane and hexadecane and with decan-1-ol. (Liquid + liquid) equilibria for the system [DDA][NO{sub 3}] with hexadecane was observed for the whole mole fraction range of the ionic liquid. The observation of the upper critical solution temperature in binary mixtures of ([DDA][NO{sub 3}] + decan-1-ol, heptane, or hexadecane) was limited by the boiling temperature of the solvent. Characterisation and purity of the compounds were determined by elemental analysis, water content (Fisher method) and differential scanning microcalorimetry (d.s.c.) analysis. The d.s.c. method of analysis was used to determine melting temperatures and enthalpies of fusion. The thermal stability of the ionic liquid was resolved by the thermogravimetric technique-differential thermal analysis (TG-DTA) technique over a wide temperature range from (200 to 780) K. The thermal decomposition temperature of 50% of the sample was greater than 500 K. The (solid + liquid) phase equilibria, curves were correlated by means of different G {sup Ex} models utilizing parameters derived from the (solid + liquid) equilibrium. The root-mean-square deviations of the solubility temperatures for all calculated data are dependent upon the particular

  6. Liquid-liquid equilibria of fuel oxygenate + water + hydrocarbon mixtures. 3: Effect of temperature

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, G. [Universitaet Karlsruhe (Germany). Institut fuer Thermische Verfahrenstechnik; Sandler, S.I. [Univ. of Delaware, Newark, DE (United States). Center for Molecular and Engineering Thermodynamics


    The authors have measured the ternary liquid-liquid equilibria of water + ethanol mixtures with, separately, 2,2,4-trimethylpentane and toluene at 5 and 40 C, water + tert-amyl alcohol (TAOH) mixtures with, separately, toluene and hexane at 5 and 40 C, and of water + TAOH + pentane mixtures at 5 C. The ethanol-containing systems exhibit type 1 liquid-liquid phase behavior, and the TAOH-containing systems exhibit type 2 behavior. These data, together with the data they have previously reported at 25 C, provide information on how the liquid-liquid equilibria of these systems change as a function of temperature. While the addition of ethanol is found to increase the solubility of hydrocarbons in the aqueous phase, the concentration of the hydrocarbon in the water-rich phase decreases with increasing temperature. With the exception of hydrocarbon in the water-rich phase, the experimental data could be correlated quite well with either the UNIQUAC or NRTL models. For most of the systems considered here the predictions of the phase behavior with the liquid-liquid UNIFAC group-contribution model are only qualitatively correct. However, the liquid-liquid UNIFAC model erroneously predicts type 2 phase behavior to occur for water + ethanol + 2,2,4-trimethylpentane system at 5 C.

  7. Experimental determination and prediction of (solid+liquid) phase equilibria for binary mixtures of heavy alkanes and fatty acids (United States)

    Benziane, Mokhtar; Khimeche, Kamel; Dahmani, Abdellah; Nezar, Sawsen; Trache, Djalal


    Solid-liquid equilibria for three binary mixtures, n-Eicosane (1) + Lauric acid (2), n-Tetracosane (1) + Stearic acid (2), and n-Octacosane (1) + Palmitic acid (2), were measured using a differential scanning calorimeter. Simple eutectic behaviour was observed for these systems. The experimental results were correlated by means of the modified UNIFAC (Larsen and Gmehling versions), UNIQUAC and ideal models. The root-mean-square deviations of the solubility temperatures for all measured data vary from 0.26 to 3.15 K and depend on the particular model used. The best solubility correlation was obtained with the UNIQUAC model.

  8. Measurement and modeling of high-pressure (vapour + liquid) equilibria of (CO{sub 2} + alcohol) binary systems

    Energy Technology Data Exchange (ETDEWEB)

    Gutierrez, Jorge E.; Bejarano, Arturo [Departamento de Ingenieria Quimica y Ambiental, Universidad Tecnica Federico Santa Maria, Avda. Espana 1680, Valparaiso (Chile); Fuente, Juan C. de la, E-mail: juan.delafuente@usm.c [Departamento de Ingenieria Quimica y Ambiental, Universidad Tecnica Federico Santa Maria, Avda. Espana 1680, Valparaiso (Chile); Centro Regional de Estudios en Alimentos Saludables, Blanco 1623, Valparaiso (Chile)


    An apparatus based on a static-analytic method assembled in this work was utilized to perform high pressure (vapour + liquid) equilibria measurements with uncertainties estimated at <5%. Complementary isothermal (vapour + liquid) equilibria results are reported for the (CO{sub 2} + 1-propanol), (CO{sub 2} + 2-methyl-1-propanol), (CO{sub 2} + 3-methyl-1-butanol), and (CO{sub 2} + 1-pentanol) binary systems at temperatures of (313, 323, and 333) K, and at pressure range of (2 to 12) MPa. For all the (CO{sub 2} + alcohol) systems, it was visually monitored to insure that there was no liquid immiscibility at the temperatures and pressures studied. The experimental results were correlated with the Peng-Robinson equation of state using the quadratic mixing rules of van der Waals with two adjustable parameters. The calculated (vapour + liquid) equilibria compositions were found to be in good agreement with the experimental values with deviations for the mol fractions <0.12 and <0.05 for the liquid and vapour phase, respectively.

  9. (Liquid + liquid) equilibria of (sulfolane + benzene + n-hexane), (N-formylmorpholine + benzene + n-hexane), and (sulfolane + N-formylmorpholine + benzene + n-hexane) at temperatures ranging from (298.15 to 318.15) K: Experimental results and correlation

    Energy Technology Data Exchange (ETDEWEB)

    Mahmoudi, Jafar [School of Chemical, Gas and Petroleum Engineering, Semnan University, Semnan 35195-363 (Iran, Islamic Republic of); Lotfollahi, Mohammad Nader, E-mail: [School of Chemical, Gas and Petroleum Engineering, Semnan University, Semnan 35195-363 (Iran, Islamic Republic of)


    The experimental (liquid + liquid) equilibrium (LLE) properties for two ternary systems containing (N-formylmorpholine + benzene + n-hexane), (sulfolane + benzene + n-hexane) and a quaternary mixed solvent system (sulfolane + N-formylmorpholine + benzene + n-hexane) were measured at temperature ranging from (298.15 to 318.15) K and at an atmospheric pressure. The experimental distribution coefficients and selectivity factors are presented to evaluate the efficiency of the solvents for extraction of benzene from n-hexane. The LLE results obtained indicate that increasing temperature decreases selectivity for all solvents. The LLE results for the systems studied were used to obtain binary interaction parameters in the UNIQUAC model by minimizing the root mean square deviations (RMSD) between the experimental and calculated results. Using the interaction parameters obtained, the phase equilibria in the systems were calculated and plotted. The calculated compositions based on the UNIQUAC model were found to be in good agreement with the experimental values. The result of the RMSD obtained by comparing the calculated and experimental two-phase compositions is 0.0163 for (N-formylmorpholine + benzene + n-hexane) system and is 0.0120 for (sulfolane + benzene + n-hexane) system.

  10. Cognitive Correlates of Different Mentalizing Abilities in Individuals with High and Low Trait Schizotypy: Findings from an Extreme-Group Design

    Directory of Open Access Journals (Sweden)

    Krisztina Kocsis-Bogár


    Full Text Available Mentalizing or Theory of Mind (ToM deficits in schizophrenia have been studied to great extent, but studies involving samples of trait schizotypy yield ambiguous results. Executive functions like cognitive inhibition, cognitive flexibility, and agency are all prerequisites of mentalizing, and it is assumed that the impairment of these functions contributes to ToM deficits in schizophrenia. Whether these impairments influence the ToM performance of people with high trait schizotypy remains unclear. Although impaired self-agency has repeatedly been identified in people with schizotypy, its role in mentalizing is yet to be investigated. The main aim of this study was to explore whether deficits in cognitive and affective ToM can be found in high trait schizotypy, and to identify in what way these deficits are related to the positive and negative dimensions of schizotypy. The secondary aim was to examine whether these deficits correlate with executive functions. Based on the dimensional view of the schizophrenia spectrum, an extreme-group design was applied to non-clinical volunteers demonstrating high (N = 39 and low (N = 47 trait schizotypy. Affective and cognitive ToM were investigated using the Movie for Assessment of Social Cognition, a sensitive and video-based measurement. Cognitive inhibition was assessed using the Stroop Test, and cognitive flexibility was analyzed using the Trail-Making Test. Agency was measured using a computerized self-agency paradigm. Participants in the high-schizotypy group performed significantly worse in the affective ToM task (d = 0.79, and their overall ToM performance was significantly impaired (d = 0.60. No between-group differences were found with regards to cognitive ToM, executive functions, and self-agency. Cognitive flexibility correlated negatively with positive schizotypy, and contributed to a worse overall and affective ToM. Impaired cognitive inhibition contributed to undermentalizing-type errors. It

  11. Modeling of Phase Equilibria Containing Associating Fluids

    DEFF Research Database (Denmark)

    Derawi, Samer; Kontogeorgis, Georgios

    . The background and main targets for this thesis are presented in Chapter 1. In Chapter 2, a comprehensive review of the application of group contribution (GC) models such as various forms of UNIFAC and the so-called AFC (Atom and Fragment Contributions) correlation model for Pow (octanol-water partition...... coefficient) calculations has been carried out. UNIFAC is an activity coefficient model while AFC is a model specifically developed for Pow calculations. Five different versions of UNIFAC and the AFC correlation model have been compared with each other and with experimental data. The range of applicability...

  12. Dynamic equilibria in an epidemic model with voluntary vaccinations. (United States)

    Chen, Frederick H; Cottrell, Allin


    The dynamics of an epidemic model with voluntary vaccinations are studied. Individual vaccination decisions are modelled using an economic/game-theoretic approach: agents in the model decide whether to vaccinate or not by weighing the cost and benefit of vaccination and choose the action that maximizes their net benefit. It is shown that, when vaccine efficacy is low, there are parameter values for which multiple steady-state equilibria and periodic equilibria coexist. When multiplicity of steady states is obtained, which one the population reaches in some cases depends entirely on agents' expectations concerning the future course of an epidemic and not on the initial conditions of the model. (†)Comments and suggestions from anonymous referees of the journal are gratefully acknowledged. This paper is dedicated to the loving memory of Lucy Hauser.

  13. On Pure and (approximate) Strong Equilibria of Facility Location Games

    DEFF Research Database (Denmark)

    Hansen, Thomas Dueholm; Telelis, Orestis A.


    We study social cost losses in Facility Location games, where n selfish agents install facilities over a network and connect to them, so as to forward their local demand (expressed by a non-negative weight per agent). Agents using the same facility share fairly its installation cost, but every...... networks we prove upper and lower bounds on PoS, while an O(ln n) upper bound implied by previous work is tight for non-metric networks. We also prove a constant upper bound for the SPoA of metric networks when strong equilibria exist. For the weighted game on general networks we prove existence of e......-approximate (e = 2.718...) strong equilibria and an upper bound of O(ln W) on SPoA (W is the sum of agents’ weights), which becomes tight Θ(ln n) for unweighted agents. Center for Algorithmic Game Theory, funded by the Carlsberg Foundation, Denmark....

  14. New families of vortex patch equilibria for the two-dimensional Euler equations (United States)

    Xue, B. B.; Johnson, E. R.; McDonald, N. R.


    Various modified forms of contour dynamics are used to compute multipolar vortex equilibria, i.e., configurations of constant vorticity patches which are invariant in a steady rotating frame. There are two distinct solution families for "N + 1" point vortex-vortex patch equilibria in which a finite-area central patch is surrounded by N identical point vortices: one with the central patch having opposite-signed vorticity and the other having same-signed vorticity to the satellite vortices. Each solution family exhibits limiting states beyond which no equilibria can be found. At the limiting state, the central patch of a same-signed equilibrium acquires N corners on its boundary. The limiting states of the opposite-signed equilibria have cusp-like behaviour on the boundary of the central patch. Linear stability analysis reveals that the central patch is most linearly unstable as it approaches the limiting states. For equilibria comprising a central patch surrounded by N identical finite-area satellite patches, again two distinct families of solutions exist: one with the central patch and satellite patches having the same-signed vorticity and the other in which they are opposite-signed. In each family, there are two limiting behaviours in which either the central patch or the satellite patches develop corners or cusps. Streamline plots and time-dependent simulations indicate that opposite-signed multipolar equilibria are robust structures and same-signed equilibria are generally less stable. Streamlines also reveal stable and unstable (saddle point) stagnation points, indicating the existence of new equilibria in which additional patches of vorticity are "grown" at the stagnation points. Examples of such equilibria are computed, and a general numerical routine is briefly described for finding even more complex finite-area equilibria. Finally, new nested polygonal vortex equilibria consisting of two sets of polygonally arranged vortex patches (named "N + N" equilibria

  15. Variational-moment method for computing magnetohydrodynamic equilibria

    Energy Technology Data Exchange (ETDEWEB)

    Lao, L.L.


    A fast yet accurate method to compute magnetohydrodynamic equilibria is provided by the variational-moment method, which is similar to the classical Rayleigh-Ritz-Galerkin approximation. The equilibrium solution sought is decomposed into a spectral representation. The partial differential equations describing the equilibrium are then recast into their equivalent variational form and systematically reduced to an optimum finite set of coupled ordinary differential equations. An appropriate spectral decomposition can make the series representing the solution coverge rapidly and hence substantially reduces the amount of computational time involved. The moment method was developed first to compute fixed-boundary inverse equilibria in axisymmetric toroidal geometry, and was demonstrated to be both efficient and accurate. The method since has been generalized to calculate free-boundary axisymmetric equilibria, to include toroidal plasma rotation and pressure anisotropy, and to treat three-dimensional toroidal geometry. In all these formulations, the flux surfaces are assumed to be smooth and nested so that the solutions can be decomposed in Fourier series in inverse coordinates. These recent developments and the advantages and limitations of the moment method are reviewed. The use of alternate coordinates for decomposition is discussed.

  16. Nash equilibria in multi-agent motor interactions.

    Directory of Open Access Journals (Sweden)

    Daniel A Braun


    Full Text Available Social interactions in classic cognitive games like the ultimatum game or the prisoner's dilemma typically lead to Nash equilibria when multiple competitive decision makers with perfect knowledge select optimal strategies. However, in evolutionary game theory it has been shown that Nash equilibria can also arise as attractors in dynamical systems that can describe, for example, the population dynamics of microorganisms. Similar to such evolutionary dynamics, we find that Nash equilibria arise naturally in motor interactions in which players vie for control and try to minimize effort. When confronted with sensorimotor interaction tasks that correspond to the classical prisoner's dilemma and the rope-pulling game, two-player motor interactions led predominantly to Nash solutions. In contrast, when a single player took both roles, playing the sensorimotor game bimanually, cooperative solutions were found. Our methodology opens up a new avenue for the study of human motor interactions within a game theoretic framework, suggesting that the coupling of motor systems can lead to game theoretic solutions.

  17. High-pressure fluid-phase equilibria: Experimental methods and systems investigated (2000-2004)

    DEFF Research Database (Denmark)

    Dohrn, Ralf; Peper, Stephanie; Fonseca, José


    , and the experimental method used for the measurements are given in 54 tables. Most of experimental data in the literature have been given for binary systems. Of the 1204 binary systems, 681 (57%) have carbon dioxide as one of the components. Information on 156 pure components, 451 ternary systems of which 267 (62......As a part of a series of reviews, a compilation of systems for which high-pressure phase-equilibrium data were published between 2000 and 2004 is given. Vapor-liquid equilibria, liquid-liquid equilibria, vapor-liquid-liquid equilibria,solid-liquid equilibria, solid-vapor equilibria, solid......-vapor-liquid equilibria, critical points, the solubility of high-boiling substances in supercritical fluids, the solubility of gases in liquids and the solubility (sorption) of volatile components in polymers are included. For the systems investigated, the reference, the temperature and pressure range of the data...

  18. The effect of electrostatic interactions on conformational equilibria of multiply substituted tetrahydropyran oxocarbenium ions. (United States)

    Yang, Michael T; Woerpel, K A


    The three-dimensional structures of dioxocarbenium ions related to glycosyl cations were determined by an analysis of spectroscopic, computational, and reactivity data. Hypothetical low-energy structures of the dioxocarbenium ions were correlated with both experimentally determined (1)H NMR coupling constants and diastereoselectivity results from nucleophilic substitution reactions. This method confirmed the pseudoaxial preference of C-3 alkoxy-substituted systems and revealed the conformational preference of the C-5 alkoxymethyl group. Although the monosubstituted C-5 alkoxymethyl substituent preferred a pseudoequatorial orientation, the C-5-C-6 bond rotation was controlled by an electrostatic effect. The preferred diaxial conformer of the trans-4,5-disubstituted tetrahydropyranyl system underscored the importance of electrostatic effects in dictating conformational equilibria. In the 2-deoxymannose system, although steric effects influenced the orientation of the C-5 alkoxymethyl substituent, the all-axial conformer was favored because of electrostatic stabilization.

  19. Phase Equilibria Measurement of Binary Mixture for the Propoxylated Neopentyl Glycol Diacrylate in Supercritical Carbon Dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Byun, Hun-Soo [Chonnam National University, Yeosu (Korea, Republic of)


    Experimental data are reported on the phase equilibrium of propoxylated neopentyl glycol diacrylate in supercritical carbon dioxide. Phase equilibria data were measured in static method at a temperature of (313.2, 333.2, 353.2, 373.2 and 393.2) K and at pressures up to 27.82 MPa. At a constant pressure, the solubility of propoxylated neopentyl glycol diacrylate for the (carbon dioxide + propoxylated neopentyl glycol diacrylate) system increases as temperature increases. The (carbon dioxide + propoxylated neopentyl glycol diacrylate) system exhibits type-I phase behavior. The experimental result for the (carbon dioxide + propoxylated neopentyl glycol diacrylate) system is correlated with Peng- Robinson equation of state using mixing rule. The critical property of propoxylated neopentyl glycol diacrylate is predicted with Joback and Lyderson method.

  20. Liquid-Liquid equilibria of the water-acetic acid-butyl acetate system

    Directory of Open Access Journals (Sweden)

    Ince E.


    Full Text Available Experimental liquid-liquid equilibria of the water-acetic acid-butyl acetate system were studied at temperatures of 298.15± 0.20, 303.15± 0.20 and 308.15± 0.20 K. Complete phase diagrams were obtained by determining solubility and tie-line data. The reliability of the experimental tie-line data was ascertained by using the Othmer and Tobias correlation. The UNIFAC group contribution method was used to predict the observed ternary liquid-liquid equilibrium (LLE data. It was found that UNIFAC group interaction parameters used for LLE did not provide a good prediction. Distribution coefficients and separation factors were evaluated for the immiscibility region.

  1. From Nash to Cournot-Nash equilibria via the Monge-Kantorovich problem. (United States)

    Blanchet, Adrien; Carlier, Guillaume


    The notion of Nash equilibria plays a key role in the analysis of strategic interactions in the framework of N player games. Analysis of Nash equilibria is however a complex issue when the number of players is large. In this article, we emphasize the role of optimal transport theory in (i) the passage from Nash to Cournot-Nash equilibria as the number of players tends to infinity and (ii) the analysis of Cournot-Nash equilibria. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  2. Isobaric vapor-liquid equilibria of tetrachloroethylene + 1-propanol and + 2-propanol at 20 and 100 kPa

    Energy Technology Data Exchange (ETDEWEB)

    Dejoz, A.; Gonzalez-Alfaro, V.; Miguel, P.J.; Vazquez, M.I. [Univ. de Valencia (Spain). Dept. de Ingenieria Quimica


    Isobaric vapor-liquid equilibria were obtained for tetrachloroethylene + 1-propanol and +2-propanol systems at 20 and 100 kPa using a dynamic still. The experimental error in temperature was {+-} 0.1 K, in pressure {+-} 0.01 kPa and {+-} 0.1 kPa for the experiments carried out at 20 and 100 kPa, respectively, and in liquid and vapor composition 0.001. The two systems satisfy the point-to-point thermodynamic consistency test. Both systems show a positive deviation from ideality. The data were well correlated with the Wilson equation.

  3. An Evaluation of the Correlation between the Free Moments Applied on the Lower Extremity and the Knee Extensor Mechanism Force in Pronated Foot Subjects during the Stance Phase of Gait


    Farzaneh Yazdani; Mohsen Razeghi; Samaneh Ebrahimi


    Background: Due to the rotatory nature of the excessive subtalar pronation and the possible impairment of the tibial rotation-knee flexion mechanism, changes of the free moment (FM) and changes of the extensor mechanism force are expected in hyper-pronated foot subjects. The purpose of this study was to evaluate the correlation between the FM applied on the lower extremity and the knee extensor mechanism force in subjects with flexible pronated feet. Methods: Fifteen asympto...

  4. Adsorption equilibria and kinetics for phenol and cresol onto polymeric adsorbents: effects of adsorbents/adsorbates structure and interface. (United States)

    Liu, Fu-Qiang; Xia, Ming-Fang; Yao, San-Li; Li, Ai-Min; Wu, Hai-Suo; Chen, Jin-Long


    Phenol and cresol (o-, m-, and p-) were selected as the adsorbates with different dipole moment (cresol>phenol, methyl being electron-drawing group) and solubility (phenol>cresol, methyl being hydrophobic group). Macropore polymers (NDA-1800 and XAD-4), hypercrosslinked polymers (NDA-100), and chemically modified adsorbents (NDA-150 and NDA-99), were comparatively used to investigate the adsorption properties including equilibria, thermodynamics and kinetics. First, all of the results about equilibria show that the adsorption data fit well to the Freundlich model. The adsorption capacity of NDA-99 and NDA-150 especially for phenol is larger in a certain extent than other three types of polymers. The hydrophobic interaction from large specific surface was mainly occurred, while the polar groups containing oxygen and amine markedly enhance the adsorption process via hydrogen interaction. Furthermore, the adsorption amount for NDA-99 and XAD-4 decrease linearly with the solubility of solutes tested. Then, the negative values of enthalpy demonstrate the predominantly exothermic and physical solid-extraction processes. Finally, the relatively more rapid adsorption process could be found onto NDA-150 than NDA-99, with the reason of the double larger pore size of the former. In conclusion, solubility of solute, together with surface area, pore size and modified groups, extremely exerts influences to the adsorption performances.

  5. Extended Group Contribution Model for Polyfunctional Phase Equilibria

    DEFF Research Database (Denmark)

    Abildskov, Jens

    Material and energy balances and equilibrium data form the basis of most design calculations. While material and energy balances may be stated without much difficulty, the design engineer is left with a choice between a wide variety of models for describing phase equilibria in the design...... of physical separation processes. In a thermodynamic sense, design requires detailed knowledge of activity coefficients in the phases at equilibrium. The prediction of these quantities from a minimum of experimental data is the broad scope of this thesis. Adequate equations exist for predicting vapor-liquid...

  6. Dynamic data evaluation for solid-liquid equilibria

    DEFF Research Database (Denmark)

    Cunico, Larissa; Ceriani, Roberta; Kang, Jeong Won

    The accuracy and reliability of the measured data sets to be used in regression of model parameters is an important issue related to modeling of phase equilibria. It is clear that good parameters for any model cannot be obtained from low quality data. A thermodynamic consistency test for solid...... of the developed tests were based in the quality tests proposed for VLE data by Kang et al. [3] and a methodology that combines solute activity coefficients in the liquid phase at infinite dilution and a theoretically based term to account for the non-ideality in dilute solutions are discussed. In this work, case...

  7. Extended Group Contribution Model for Polyfunctional Phase Equilibria

    DEFF Research Database (Denmark)

    Abildskov, Jens

    Material and energy balances and equilibrium data form the basis of most design calculations. While material and energy balances may be stated without much difficulty, the design engineer is left with a choice between a wide variety of models for describing phase equilibria in the design...... of physical separation processes. In a thermodynamic sense, design requires detailed knowledge of activity coefficients in the phases at equilibrium. The prediction of these quantities from a minimum of experimental data is the broad scope of this thesis. Adequate equations exist for predicting vapor...

  8. Analytical calculation of boozer magnetic coordinates for axisymmetric MHD equilibria

    Energy Technology Data Exchange (ETDEWEB)

    Alladio, F.; Micozzi, P. [ENEA, Centro Ricerche Frascati, Rome (Italy). Dip. Energia


    A new analytical technique for extracting the Boozer magnetic coordinates in axisymmetric MHD equilibria is described. The method is based upon the correspondence between the expansion of the flux function in toroidal multipolar moments and the expansion in toroidal axisymmetric harmonics of the magnetic scalar potential {chi}{sub 0}, which appears in the covariant representation B={nabla}{sub {chi}0}+{beta}{nabla}{sub {psi}}-T of the magnetic field. An example of calculation of Boozer magnetic coordinates is given for an experimental highly shaped high {beta} equilibrium of DIIID.

  9. Extended Group Contribution Model for Polyfunctional Phase Equilibria

    DEFF Research Database (Denmark)

    Abildskov, Jens

    of physical separation processes. In a thermodynamic sense, design requires detailed knowledge of activity coefficients in the phases at equilibrium. The prediction of these quantities from a minimum of experimental data is the broad scope of this thesis. Adequate equations exist for predicting vapor-liquid......Material and energy balances and equilibrium data form the basis of most design calculations. While material and energy balances may be stated without much difficulty, the design engineer is left with a choice between a wide variety of models for describing phase equilibria in the design...

  10. Mathematical Model for Multicomponent Adsorption Equilibria Using Only Pure Component Data

    DEFF Research Database (Denmark)

    Marcussen, Lis


    A mathematical model for nonideal adsorption equilibria in multicomponent mixtures is developed. It is applied with good results for pure substances and for prediction of strongly nonideal multicomponent equilibria using only pure component data. The model accounts for adsorbent-adsorbate and ads...

  11. The Responsiveness and Correlation between Fugl-Meyer Assessment, Motor Status Scale, and the Action Research Arm Test in Chronic Stroke with Upper-Extremity Rehabilitation Robotic Training (United States)

    Wei, Xi-Jun; Tong, Kai-yu; Hu, Xiao-ling


    Responsiveness of clinical assessments is an important element in the report of clinical effectiveness after rehabilitation. The correlation could reflect the validity of assessments as an indication of clinical performance before and after interventions. This study investigated the correlation and responsiveness of Fugl-Meyer Assessment (FMA),…

  12. Phase equilibria of the Mo-Al-Ho ternary system

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yitai; Chen, Xiaoxian; Liu, Hao [Guangxi Univ., Nanning (China). College of Materials Science and Engineering; Guangxi Univ., Nanning (China). Guangxi Key Laboratory of Processing for Non-ferrous Metal and Featured Materials; Zhan, Yongzhong [Guangxi Univ., Nanning (China). College of Materials Science and Engineering; Guangxi Univ., Nanning (China). Guangxi Key Laboratory of Processing for Non-ferrous Metal and Featured Materials; Guangxi Univ., Nanning (China). Center of Ecological Collaborative Innovation for Aluminum Industry


    Investigation into the reactions and phase equilibria of transition metal elements (i.e. Mo, Zr, Cr, V and Ti), Al and rare earths is academically and industrially important for the development of both refractory alloys and lightweight high-temperature materials. In this work, the equilibria of the Mo-Al-Ho ternary system at 773 K have been determined by using X-ray powder diffraction and scanning electron microscopy equipped with energy dispersive X-ray analysis. A new ternary phase Al{sub 4}Mo{sub 2}Ho has been found and the other ternary phase Al{sub 43}Mo{sub 4}Ho{sub 6} is observed. Ten binary phases in the Al-Mo and Al-Ho systems, including Al{sub 17}Mo{sub 4} rather than Al{sub 4}Mo, have been determined to exist at 773 K. The homogeneity ranges of AlMo{sub 3} and Al{sub 8}Mo{sub 3} phase are 7.5 at.% and 1 at.%, respectively. According to the phase-disappearing method, the maximum solubility of Al in Mo is about 16 at.%.

  13. Equilibria near asteroids for solar sails with reflection control devices (United States)

    Gong, Shengping; Li, Junfeng


    Solar sails are well-suited for long-term, multiple-asteroid missions. The dynamics of solar sails near an asteroid have not yet been studied in detail. In this paper, out-of-plane artificial equilibria in a Sun-asteroid rotating frame and hovering points in a body-fixed rotating frame are studied (using a solar sail equipped with reflection control devices). First, the dynamics and the stability of out-of-plane artificial equilibria are studied as an elliptical restricted three body problem. Next, the body-fixed hovering problem is discussed as a two-body problem. Hovering flight is only possible for certain values of the latitude of the asteroid's orbit. In addition, the feasible range of latitudes is determined for each landmark on the asteroid's surface. The influence of the sail lightness number on the feasible range is also illustrated. Several special families of hovering points are discussed. These points include points above the equator and poles and points with an altitude equal to the radius of the synchronous orbit. In both of these types of problems, the solar sail (equipped with reflection control devices) can equilibrate over a large range of locations.

  14. Conformational equilibria and intrinsic affinities define integrin activation. (United States)

    Li, Jing; Su, Yang; Xia, Wei; Qin, Yan; Humphries, Martin J; Vestweber, Dietmar; Cabañas, Carlos; Lu, Chafen; Springer, Timothy A


    We show that the three conformational states of integrin α5β1 have discrete free energies and define activation by measuring intrinsic affinities for ligand of each state and the equilibria linking them. The 5,000-fold higher affinity of the extended-open state than the bent-closed and extended-closed states demonstrates profound regulation of affinity. Free energy requirements for activation are defined with protein fragments and intact α5β1 On the surface of K562 cells, α5β1 is 99.8% bent-closed. Stabilization of the bent conformation by integrin transmembrane and cytoplasmic domains must be overcome by cellular energy input to stabilize extension. Following extension, headpiece opening is energetically favored. N-glycans and leg domains in each subunit that connect the ligand-binding head to the membrane repel or crowd one another and regulate conformational equilibria in favor of headpiece opening. The results suggest new principles for regulating signaling in the large class of receptors built from extracellular domains in tandem with single-span transmembrane domains. © 2017 The Authors. Published under the terms of the CC BY 4.0 license.

  15. Extreme cosmos

    CERN Document Server

    Gaensler, Bryan


    The universe is all about extremes. Space has a temperature 270°C below freezing. Stars die in catastrophic supernova explosions a billion times brighter than the Sun. A black hole can generate 10 million trillion volts of electricity. And hypergiants are stars 2 billion kilometres across, larger than the orbit of Jupiter. Extreme Cosmos provides a stunning new view of the way the Universe works, seen through the lens of extremes: the fastest, hottest, heaviest, brightest, oldest, densest and even the loudest. This is an astronomy book that not only offers amazing facts and figures but also re

  16. Relativistic Self-similar Equilibria and Non-axisymmetric Neutral Modes (United States)

    Cai, Mike J.; Shu, F. H.


    We have constructed semi-analytic axisymmetric scale free solutions to Einstein field equations with perfect fluid matter source. These spacetimes are self-similar under the simultaneous transformation r'= ar and t'=a1-nt. We explored the two dimensional solution space parameterized by the rescaling index n and the isothermal sound speed γ 1/2. The isopycnic surfaces are in general toroids. As the equilibrium configuration rotates faster, an ergo region develops in the form of the exterior of a cone centered about the symmetry axis. The sequence of solution terminates when frame dragging becomes infinite and the ergo cone closes onto the axis. In the extreme flattening limit, we have also searched for non-axisymmetric neutral modes in a self-similar disk. Two separate sets of tracks are discovered in the solution space. One corresponds to the bifurcation points to non-axisymmetric equilibria, which is confined in the non-ergo solutions. The other track signals the onset of instability driven by gravitational radiation. These solutions are formally infinite in extent, and thus can not represent realistic astrophysical systems. However, if these properties do not alter qualitatively when the self-similar configurations are truncated, then these solutions may serve as initial data for dynamic collapse in super massive black hole formation.

  17. High-pressure fluid phase equilibria phenomenology and computation

    CERN Document Server

    Deiters, Ulrich K


    The book begins with an overview of the phase diagrams of fluid mixtures (fluid = liquid, gas, or supercritical state), which can show an astonishing variety when elevated pressures are taken into account; phenomena like retrograde condensation (single and double) and azeotropy (normal and double) are discussed. It then gives an introduction into the relevant thermodynamic equations for fluid mixtures, including some that are rarely found in modern textbooks, and shows how they can they be used to compute phase diagrams and related properties. This chapter gives a consistent and axiomatic approach to fluid thermodynamics; it avoids using activity coefficients. Further chapters are dedicated to solid-fluid phase equilibria and global phase diagrams (systematic search for phase diagram classes). The appendix contains numerical algorithms needed for the computations. The book thus enables the reader to create or improve computer programs for the calculation of fluid phase diagrams. introduces phase diagram class...

  18. Gas hydrate phase equilibria measurement techniques and phase rule considerations

    Energy Technology Data Exchange (ETDEWEB)

    Beltran, Juan G. [Department of Chemistry and Chemical Engineering, Royal Military College of Canada, Kingston, ON (Canada); Bruusgaard, Hallvard [Department of Chemical Engineering, McGill University, Montreal, QC (Canada); Servio, Phillip, E-mail: [Department of Chemical Engineering, McGill University, Montreal, QC (Canada)


    Highlights: > Inconsistencies found in hydrate literature. > Clarification to the number of variables needed to satisfy and justify equilibrium data. > Application of phase rule to mixed hydrate systems. > Thermodynamically consistent format to present data. - Abstract: A brief review of the Gibbs phase rule for non-reacting systems and its correct application to clathrate hydrates is presented. Clarification is provided for a common mistake found in hydrate phase-equilibria literature, whereby initial compositions are used as intensive variables to satisfy the Gibbs phase rule instead of the equilibrium values. The system of (methane + carbon dioxide + water) under (hydrate + liquid + vapor) equilibrium is used as a case study to illustrate key points and suggestions to improve experimental techniques are proposed.

  19. Navigable networks as Nash equilibria of navigation games (United States)

    Gulyás, András; Bíró, József J.; Kőrösi, Attila; Rétvári, Gábor; Krioukov, Dmitri


    Common sense suggests that networks are not random mazes of purposeless connections, but that these connections are organized so that networks can perform their functions well. One function common to many networks is targeted transport or navigation. Here, using game theory, we show that minimalistic networks designed to maximize the navigation efficiency at minimal cost share basic structural properties with real networks. These idealistic networks are Nash equilibria of a network construction game whose purpose is to find an optimal trade-off between the network cost and navigability. We show that these skeletons are present in the Internet, metabolic, English word, US airport, Hungarian road networks, and in a structural network of the human brain. The knowledge of these skeletons allows one to identify the minimal number of edges, by altering which one can efficiently improve or paralyse navigation in the network. PMID:26138277

  20. Rotational equilibria by Lagrangian variational principle: towards multidimensional stellar evolutions (United States)

    Yasutake, Nobutoshi; Fujisawa, Kotaro; Yamada, Shoichi


    We have developed a new formulation to obtain self-gravitating, axisymmetric configurations in permanent rotation. The formulation is based on the Lagrangian variational principle with a triangulated mesh. It treats not only barotropic but also baroclinic equations of state. We compare the various stellar equilibria obtained by our new scheme with those by Hachisu's self-consistent field scheme for the barotropic case, and those by Fujisawa's self-consistent field scheme for the baroclinic case. Included in these rotational configurations are those with shellular-type rotations, which are commonly assumed in the evolution calculation of rotating stars. Although radiation processes, convections and meridional flows have not been taken into account in this study, we have in mind the application of this method to the two-dimensional evolution calculations of rotating stars, for which the Lagrangian formulation is best suited.

  1. Extended Group Contribution Model for Polyfunctional Phase Equilibria

    DEFF Research Database (Denmark)

    Abildskov, Jens

    -liquid equilibria from data on binary mixtures, composed of structurally simple molecules with a single functional group. More complex is the situation with mixtures composed of structurally more complicated molecules or molecules with more than one functional group. The UNIFAC method is extended to handle...... on ideas applied to modelling of pure component properties. Chapter 2 describes the conceptual background of the approach. Three extensions of the present first-order UNIFAC model are formulated in chapter 3. These obey the Gibbs-Duhem restriction, and satisfy other traditional consistency requirements....... In chapter 4 parameters are estimated for the first-order UNIFAC model, based on which parameters are estimated for one of the second-order models described in chapter 3. The parameter estimation is based on measured binary data on around 4000 systems, covering 11 C-, H- and O-containing functional groups...

  2. Navigable networks as Nash equilibria of navigation games (United States)

    Gulyás, András; Bíró, József J.; Kőrösi, Attila; Rétvári, Gábor; Krioukov, Dmitri


    Common sense suggests that networks are not random mazes of purposeless connections, but that these connections are organized so that networks can perform their functions well. One function common to many networks is targeted transport or navigation. Here, using game theory, we show that minimalistic networks designed to maximize the navigation efficiency at minimal cost share basic structural properties with real networks. These idealistic networks are Nash equilibria of a network construction game whose purpose is to find an optimal trade-off between the network cost and navigability. We show that these skeletons are present in the Internet, metabolic, English word, US airport, Hungarian road networks, and in a structural network of the human brain. The knowledge of these skeletons allows one to identify the minimal number of edges, by altering which one can efficiently improve or paralyse navigation in the network.

  3. Analytical solutions for Tokamak equilibria with reversed toroidal current

    Energy Technology Data Exchange (ETDEWEB)

    Martins, Caroline G. L.; Roberto, M.; Braga, F. L. [Departamento de Fisica, Instituto Tecnologico de Aeronautica, Sao Jose dos Campos, Sao Paulo 12228-900 (Brazil); Caldas, I. L. [Instituto de Fisica, Universidade de Sao Paulo, 05315-970 Sao Paulo, SP (Brazil)


    In tokamaks, an advanced plasma confinement regime has been investigated with a central hollow electric current with negative density which gives rise to non-nested magnetic surfaces. We present analytical solutions for the magnetohydrodynamic equilibria of this regime in terms of non-orthogonal toroidal polar coordinates. These solutions are obtained for large aspect ratio tokamaks and they are valid for any kind of reversed hollow current density profiles. The zero order solution of the poloidal magnetic flux function describes nested toroidal magnetic surfaces with a magnetic axis displaced due to the toroidal geometry. The first order correction introduces a poloidal field asymmetry and, consequently, magnetic islands arise around the zero order surface with null poloidal magnetic flux gradient. An analytic expression for the magnetic island width is deduced in terms of the equilibrium parameters. We give examples of the equilibrium plasma profiles and islands obtained for a class of current density profile.

  4. Three-dimensional equilibria in axially symmetric tokamaks (United States)

    Garabedian, Paul R.


    The NSTAB and TRAN computer codes have been developed to study equilibrium, stability, and transport in fusion plasmas with three-dimensional (3D) geometry. The numerical method that is applied calculates islands in tokamaks like the Doublet III-D at General Atomic and the International Thermonuclear Experimental Reactor. When bifurcated 3D solutions are used in Monte Carlo computations of the energy confinement time, a realistic simulation of transport is obtained. The significance of finding many 3D magnetohydrodynamic equilibria in axially symmetric tokamaks needs attention because their cumulative effect may contribute to the prompt loss of α particles or to crashes and disruptions that are observed. The 3D theory predicts good performance for stellarators. PMID:17159158

  5. Abnormal Patella Height Based on Insall-Salvati Ratio and its Correlation with Patellar Cartilage Lesions: An Extremity-Dedicated Low-Field Magnetic Resonance Imaging Analysis of 1703 Chinese Cases. (United States)

    Lu, W; Yang, J; Chen, S; Zhu, Y; Zhu, C


    Diagnostic performance of patellar position for patellar cartilage lesions remains unclear. The aim of this study was to assess the abnormal patella height and its correlation with chondral lesions of the patellofemoral joint in China. A total of 1703 consecutive patients who performed knee joint examination using an extremity-dedicated low-field magnetic resonance imaging were enrolled in this study. Patellar cartilage lesions were diagnosed based on the result of magnetic resonance imaging and clinical data. Patella height was defined as the ratio of patellar tendon length to patellar length according to Insall-Salvati index. Patella alta and infera were defined as tendon length/patellar length >1.2 and patella alta and infera (p patella height had statistical significance in diagnosing cartilage lesions (p patella height is significantly correlated with chondral lesions and can be used as a potential diagnostic marker. © The Finnish Surgical Society 2015.

  6. Relative Equilibria of a Rigid Satellite in a Central Gravitational Field

    National Research Council Canada - National Science Library

    Beck, Jeffrey


    .... These equilibria correspond to fixed points of a reduced set of equations expressed in a rotating frame and are representative of an orbiting satellite with fixed attitude relative to an observer...

  7. New investigation of phase equilibria in the system Al–Cu–Si


    Ponweiser, Norbert; Richter, Klaus W.


    The phase equilibria and invariant reactions in the system Al?Cu?Si were investigated by a combination of optical microscopy, powder X-ray diffraction (XRD), differential thermal analysis (DTA) and electron probe micro analysis (EPMA). Isothermal phase equilibria were investigated within two isothermal sections. The isothermal section at 500??C covers the whole ternary composition range and largely confirms the findings of previous phase diagram investigations. The isothermal section at 700??...

  8. Thermodynamic characteristics of protolytic equilibria in aqueous solutions of glycyl peptides (United States)

    Gridchin, S. N.


    Protolytic equilibria in aqueous solutions of glycyl-DL-serine, glycyl-DL-threonine, and glycyl-DL-valine are investigated by means of potentiometry and calorimetry. Dissociation constants and heat effects of the above dipeptides are determined. Standard thermodynamic characteristics (p K°, Δdis G°, Δdis H°, Δdis S°) of the investigated equilibria are calculated. The obtained results are compared to corresponding data on relative compounds.

  9. The double-helical branch structure of fixed contact line liquid bridge equilibria (United States)

    Lowry, Brian J.


    Attempts to stabilize the fixed contact line cylindrical liquid bridge have generally implicitly assumed that it was related to stable equilibria in a continuous manner. An examination of the branch structure of equilibria demonstrates that for longer liquid bridges, the cylinder becomes separate from normally stable equilibria and hence likely cannot be stabilized by a continuous perturbation. All axisymmetric equilibria for a fixed contact line liquid bridge of fixed moderate length in the absence of applied forces (zero gravity, no spin) are found to lie on a single semi-infinite bridged double helix. This helix breaks repeatedly as the length of the liquid bridge is increased, separating the stable truncated sphere state from the generally desirable cylindrical state. This structural change appears to explain why several approaches to stabilization of long cylindrical liquid bridges beyond the classical Plateau-Rayleigh limit have been largely unsuccessful over the past few decades. The first breakage of the helix, when liquid bridge length equals 9.0973 times radius, corresponds roughly to the maximum length of cylindrical liquid bridge achieved experimentally via a perturbative applied force (using acoustic radiation pressure). An examination of the deformations of the helix under gravity reveals that for moderate length liquid bridges at small Bond number, all axisymmetric equilibria lie on a single unbroken branch which forms a single (unbridged) semi-infinite double helix. Combined effects of gravity and length are investigated as well, resulting in multiple disconnected loops of equilibria.

  10. Within-prison drug injection among HIV-infected Ukrainian prisoners: prevalence and correlates of an extremely high-risk behaviour. (United States)

    Izenberg, Jacob M; Bachireddy, Chethan; Wickersham, Jeffrey A; Soule, Michael; Kiriazova, Tetiana; Dvoriak, Sergii; Altice, Frederick L


    In Ukraine, HIV-infection, injection drug use, and incarceration are syndemic; however, few services are available to incarcerated people who inject drugs (PWIDs). While data are limited internationally, within-prison drug injection (WP-DI) appears widespread and may pose significant challenges in countries like Ukraine, where PWIDs contribute heavily to HIV incidence. To date, WP-DI has not been specifically examined among HIV-infected prisoners, the only persons that can transmit HIV. A convenience sample of 97 HIV-infected adults recently released from prison within 1-12 months was recruited in two major Ukrainian cities. Post-release surveys inquired about WP-DI and injection equipment sharing, as well as current and prior drug use and injection, mental health, and access to within-prison treatment for HIV and other comorbidities. Logistic regression identified independent correlates of WP-DI. Complete data for WP-DI were available for 95 (97.9%) respondents. Overall, 54 (56.8%) reported WP-DI, among whom 40 (74.1%) shared injecting equipment with a mean of 4.4 (range 0-30) other injectors per needle/syringe. Independent correlates of WP-DI were recruitment in Kyiv (AOR 7.46, p=0.003), male gender (AOR 22.07, p=0.006), and active pre-incarceration opioid use (AOR 8.66, p=0.005). Among these recently released HIV-infected prisoners, WP-DI and injection equipment sharing were frequent and involved many injecting partners per needle/syringe. The overwhelming majority of respondents reporting WP-DI used opioids both before and after incarceration, suggesting that implementation of evidence-based harm reduction practices, such as opioid substitution therapy and/or needle/syringe exchange programmes within prison, is crucial to addressing continuing HIV transmission among PWIDs within prison settings. The positive correlation between Kyiv site and WP-DI suggests that additional structural interventions may be useful. Copyright © 2014 Elsevier B.V. All rights

  11. Performance of density functionals for modeling vapor liquid equilibria of CO2 and SO2. (United States)

    Goel, Himanshu; Windom, Zachary W; Jackson, Amber A; Rai, Neeraj


    Vapor liquid equilibria (VLE) and condensed phase properties of carbon dioxide and sulfur dioxide are calculated using first principles Monte Carlo (FPMC) simulations to assess the performance of several density functionals, notably PBE-D3, BLYP-D3, PBE0-D3, M062X-D3, and rVV10. GGA functionals were used to compute complete vapor liquid coexistence curves (VLCCs) to estimate critical properties, while the hybrid and nonlocal van der Waals functionals were used only for computing density at a single state point due to the high computational cost. Our results show that the BLYP-D3 functional performs well in predicting VLE properties for both molecules when compared with other functionals. In the liquid phase, pair correlation functions reveal that there is not a significant difference in the location of the peak for the first solvation shell while the peak heights are different for different functionals. Overall, the BLYP-D3 functional is a good choice for modeling VLE of acidic gases with significant environmental implications such as CO2 and SO2 . © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  12. Phase equilibria and modeling of ammonium ionic liquid, C2NTf2, solutions. (United States)

    Domańska, Urszula; Marciniak, Andrzej; Królikowski, Marek


    Novel quaternary ammonium ionic liquid, ethyl(2-hydroxyethyl)dimethylammonium bis(trifluomethylsulfonyl)imide (C2NTf2), has been prepared from N,N-dimethylethanolamine as a substrate. The paper includes a specific basic characterization of the synthesized compound by NMR and the basic thermophysical properties: the melting point, enthalpy of fusion, enthalpy of solid-solid phase transition, glass transition determined by the differential scanning calorimetry (DSC), temperature of decomposition, and water content. The density of the new compound was measured. The solid-liquid or liquid-liquid phase equilibria of binary mixtures containing {C2NTf2+water or an alcohol (propan-1-ol, butan-1-ol, hexan-1-ol, octan-1-ol, decan-1-ol), aromatic hydrocarbons (benzene, toluene), aliphatic hydrocarbons (n-hexane, n-octane), dimethylsulfoxide (DMSO), or tetrahydrofuran (THF)} have been measured by a dynamic method in a wide range of temperatures from 230 to 430 K. These data were correlated by means of the nonrandom two-liquid (NRTL) equation utilizing temperature-dependent parameters derived from the solid-liquid or liquid-liquid equilibrium. From the solubility results, the negative value of the partition coefficient of ionic liquid in binary system octan-1-ol/water (log P) at 298.15 K has been calculated.

  13. An Evaluation of the Correlation between the Free Moments Applied on the Lower Extremity and the Knee Extensor Mechanism Force in Pronated Foot Subjects during the Stance Phase of Gait

    Directory of Open Access Journals (Sweden)

    Farzaneh Yazdani


    Full Text Available Background: Due to the rotatory nature of the excessive subtalar pronation and the possible impairment of the tibial rotation-knee flexion mechanism, changes of the free moment (FM and changes of the extensor mechanism force are expected in hyper-pronated foot subjects. The purpose of this study was to evaluate the correlation between the FM applied on the lower extremity and the knee extensor mechanism force in subjects with flexible pronated feet. Methods: Fifteen asymptomatic female subjects (21.32±1.66 y, 56.30±6.08 kg, 159±6.3 cm participated in the study. Excessive subtalar pronation was determined by measuring the resting calcaneal stance position (RCSP in the frontal plane during weight bearing. A neutrally aligned foot was defined as having an RCSP between 2° of inversion and 2° of eversion. On the other hand, a flat foot had an RCSP of more than or equal to 4° of eversion. Both kinetic and kinematic data were collected using a six-camera motion analysis system and a single force plate. Three successful barefoot walking trials were recorded at selfselected speeds. The extensor mechanism force and the adductory component of the free moment (ADD FM were calculated. The correlation between the ADD FM and the knee extensor mechanism force was examined using the Pearson correlation test. Results: The Pearson correlation analysis showed a high positive correlation between the ADD FM and the extensor mechanism force (r=0.917, P<0.001. Conclusion: Excessive subtalar pronation, along with a possible impairment of the tibial rotation-knee flexion mechanism, may affect the extensor mechanism force at the knee joint. From a clinical perspective, the possible biomechanical linkage between the knee and the foot complex in the physical examination and treatment of patients should be considered.

  14. High-pressure vapor-liquid equilibria of two binary systems: Carbon dioxide + cyclohexanol and carbon dioxide + cyclohexanone

    Energy Technology Data Exchange (ETDEWEB)

    Laugier, S. [Ecole Nationale Superieure de Chimie et Physique de Bordeaux, Talence (France); Richon, D. [Ecole Nationale Superieure des Mines de Paris, Fontainebleau (France)


    Vapor-liquid equilibria for carbon dioxide + cyclohexanol and carbon dioxide + cyclohexanone were measured using an apparatus based on a static-analytic method with in situ samplings. P, T, x, y measurements were made at pressures up to 22 MPa. The carbon dioxide + cyclohexanol system was studied at 433 and 473 K, and carbon dioxide + cyclohexanone, at 433 and 473 K. The results are correlated by the Redlich-Kwong-Soave and Peng and Robinson equations and several mixing rules. The best fittings are obtained with the Peng-Robinson equation of state and a two-parameter mixing rule, i.e., within 1.1% for both pressures and vapor mole fractions on the carbon dioxide + cyclohexanone system and within 1.9% for pressures and 2.9% for vapor mole fractions on the carbon dioxide + cyclohexanol system. More recent equations by Patel and Teja and Salim and Trebble show no significant advantages.

  15. Relaxed MHD equilibria inside 3D shaped conducting surfaces (United States)

    Hassam, A.; Tenbarge, J.; Dorland, W.; Landreman, M.; Sengupta, W.


    A 3D nonlinear dissipative MHD code is developed to allow relaxation to low-beta MHD equilibrium inside a shaped 3D conducting boundary with prescribed conserved axial magnetic flux and no external current. Formation of magnetic islands is allowed. Heat sources would be eventually introduced to allow possible non-stationary convection depending on the MHD stability properties. The initial development is done using UMHD (Guzdar et al., PF, 1993). A primary objective is to minimize numerical boundary noise. In particular, codes which specify the normal magnetic field B.n on bounding surfaces are prone to boundary noise generation. We shape the boundary to conform to the desired field shape so that B.n is zero on the boundary, employing curvilinear coordinates. Significant noise reduction has been achieved by this approach. Boundary noise is strongly suppressed if the boundary is modeled as a sharp ramp-down in resistivity, allowing relaxation to equilibrium but no penetration into the low resistivity region. Initial results have been verified w.r.t. analytic calculation in the weak shaping limit. A rotational transform is observed in helical shaping. Relaxed equilibria inside helically symmetric conducting boundaries will be presented.

  16. Equilibria of idealized confined astral microtubules and coupled spindle poles.

    Directory of Open Access Journals (Sweden)

    Ivan V Maly

    Full Text Available Positioning of the mitotic spindle through the interaction of astral microtubules with the cell boundary often determines whether the cell division will be symmetric or asymmetric. This process plays a crucial role in development. In this paper, a numerical model is presented that deals with the force exerted on the spindle by astral microtubules that are bent by virtue of their confinement within the cell boundary. It is found that depending on parameters, the symmetric position of the spindle can be stable or unstable. Asymmetric stable equilibria also exist, and two or more stable positions can exist simultaneously. The theory poses new types of questions for experimental research. Regarding the cases of symmetric spindle positioning, it is necessary to ask whether the microtubule parameters are controlled by the cell so that the bending mechanics favors symmetry. If they are not, then it is necessary to ask what forces external to the microtubule cytoskeleton counteract the bending effects sufficiently to actively establish symmetry. Conversely, regarding the cases with asymmetry, it is now necessary to investigate whether the cell controls the microtubule parameters so that the bending favors asymmetry apart from any forces that are external to the microtubule cytoskeleton.

  17. Spectrum Allocation for Decentralized Transmission Strategies: Properties of Nash Equilibria

    Directory of Open Access Journals (Sweden)

    Peter von Wrycza


    Full Text Available The interaction of two transmit-receive pairs coexisting in the same area and communicating using the same portion of the spectrum is analyzed from a game theoretic perspective. Each pair utilizes a decentralized iterative water-filling scheme to greedily maximize the individual rate. We study the dynamics of such a game and find properties of the resulting Nash equilibria. The region of achievable operating points is characterized for both low- and high-interference systems, and the dependence on the various system parameters is explicitly shown. We derive the region of possible signal space partitioning for the iterative water-filling scheme and show how the individual utility functions can be modified to alter its range. Utilizing global system knowledge, we design a modified game encouraging better operating points in terms of sum rate compared to those obtained using the iterative water-filling algorithm and show how such a game can be imitated in a decentralized noncooperative setting. Although we restrict the analysis to a two player game, analogous concepts can be used to design decentralized algorithms for scenarios with more players. The performance of the modified decentralized game is evaluated and compared to the iterative water-filling algorithm by numerical simulations.

  18. Transitions of Spherical Thermohaline Circulation to Multiple Equilibria (United States)

    Özer, Saadet; Şengül, Taylan


    The main aim of the paper is to investigate the transitions of the thermohaline circulation in a spherical shell in a parameter regime which only allows transitions to multiple equilibria. We find that the first transition is either continuous (Type-I) or drastic (Type-II) depending on the sign of the transition number. The transition number depends on the system parameters and l_c , which is the common degree of spherical harmonics of the first critical eigenmodes, and it can be written as a sum of terms describing the nonlinear interactions of various modes with the critical modes. We obtain the exact formulas of this transition number for l_c=1 and l_c=2 cases. Numerically, we find that the main contribution to the transition number is due to nonlinear interactions with modes having zero wave number and the contribution from the nonlinear interactions with higher frequency modes is negligible. In our numerical experiments we encountered both types of transition for Le1 . In the continuous transition scenario, we rigorously prove that an attractor in the phase space bifurcates which is homeomorphic to the 2l_c dimensional sphere and consists entirely of degenerate steady state solutions.

  19. Calculation of Binary Adsorption Equilibria: Hydrocarbons and Carbon Dioxide on Activated Carbon

    DEFF Research Database (Denmark)

    Marcussen, Lis; Krøll, A.


    Binary adsorption equilibria are calculated by means of a mathematical model for multicomponent mixtures combined with the SPD (Spreading Pressure Dependent) model for calculation of activity coefficients in the adsorbed phase. The model has been applied successfully for the adsorption of binary ...... mixtures of hydrocarbons and carbon dioxide on activated carbons. The model parameters have been determined, and the model has proven to be suited for prediction of adsorption equilibria in the investigated systems.......Binary adsorption equilibria are calculated by means of a mathematical model for multicomponent mixtures combined with the SPD (Spreading Pressure Dependent) model for calculation of activity coefficients in the adsorbed phase. The model has been applied successfully for the adsorption of binary...

  20. Lagrangian relative equilibria for a gyrostat in the three-body problem: bifurcations and stability

    Energy Technology Data Exchange (ETDEWEB)

    Guirao, Juan L G; Vera, Juan A, E-mail: juan.garcia@upct.e, E-mail: juanantonio.vera@upct.e [Departamento de Matematica Aplicada y EstadIstica, Universidad Politecnica de Cartagena, Hospital de Marina, 30203 Cartagena, Region de Murcia (Spain)


    In this paper we consider the non-canonical Hamiltonian dynamics of a gyrostat in the frame of the three-body problem. Using geometric/mechanic methods we study the approximate dynamics of the truncated Legendre series representation of the potential of an arbitrary order. Working in the reduced problem, we study the existence of relative equilibria that we refer to as Lagrange type following the analogy with the standard techniques. We provide necessary and sufficient conditions for the linear stability of Lagrangian relative equilibria if the gyrostat morphology form is close to a sphere. Thus, we generalize the classical results on equilibria of the three-body problem and many results on them obtained by the classic approach for the case of rigid bodies.

  1. A note on relative equilibria in a rotating shallow water layer

    KAUST Repository

    Ait Abderrahmane, Hamid


    Relative equilibria of two and three satellite vortices in a rotating shallow water layer have been recorded via particle image velocimetry (PIV) and their autorotation speed was estimated. This study shows that these equilibria retain the fundamental characteristics of Kelvin\\'s equilibria, and could be adequately described by the classical idealized point vortex theory. The same conclusion can also be inferred using the experimental dataset of Bergmann et al. (J. Fluid Mech., vol. 679, 2011, pp. 415-431; J. Fluid Mech., vol. 691, 2012, pp. 605-606) if the assigned field\\'s contribution to pattern rotation is included. © 2013 Cambridge University Press.


    Directory of Open Access Journals (Sweden)

    Nélio T. MACHADO


    Full Text Available Vapor-Liquid equilibria of palm fatty acids distillates/carbon dioxide system has been investigated experimentally at temperatures of 333, 353, and 373 K and pressures of 20, 23, 26, and 29 MPa using the static method. Experimental data for the quasi-binary system palm fatty acids distillates/carbon dioxide has been correlated with Redlich-Kwong-Aspen equation of state. Modeling shows good agreement with experimental data. Selectivity obtained indicates that supercritical carbon dioxide is a reasonable solvent for separating saturated (palmitic acid and unsaturated (oleic+linoleic acids fatty acids from palm fatty acids distillates in a continuous multistage countercurrent column.Foi investigado experimentalmente o equilíbrio líquido-vapor para o sistema Destilado Ácido de Óleo de Palma (PFAD/Dióxido de Carbono, nas temperaturas de 333, 353 e 373 K e pressões de 20, 23, 26 e 29 MPa, usando-se o método estático. Os dados experimentais do sistema pseudo-binário PFAD/CO2 foram correlacionados com a equação de estado de Redlich-Kwong do pacote computacional ASPEN. O modelo reproduz bem os resultados experimentais. A seletividade obtida indica que o CO2 supercrítico é um solvente razoável para a separação em coluna multi-estágio e contínua, do ácido graxo saturado (ácido palmítico daqueles insaturados (ácido oleico e ácido linoleico contidos no PFAD.

  3. A dynamical view of different solution paradigms in two-person symmetric games: Nash vs co-action equilibria

    CERN Document Server

    Sasidevan, V


    The study of games and their equilibria is central to developing insights for understanding many socio-economic phenomena. Here we present a dynamical systems view of the equilibria of two-person, payoff-symmetric games. In particular, using this perspective, we discuss the differences between two solution concepts for such games - namely, those of Nash equilibrium and co-action equilibrium. For the Nash equilibrium, we show that the dynamical view can provide an equilibrium refinement, selecting one equilibrium among several possibilities, thereby solving the issue of multiple equilibria that appear in some games. We illustrate in detail this dynamical perspective by considering three well known 2-person games namely the Prisoner's Dilemma, game of Chicken and the Stag-Hunt. We find that in all of these cases, co-action equilibria tends to correspond to `nicer' strategies than those corresponding to Nash equilibria.

  4. Existence of three-dimensional ideal-magnetohydrodynamic equilibria with current sheets

    Energy Technology Data Exchange (ETDEWEB)

    Loizu, J. [Max-Planck-Institut für Plasmaphysik, D-17491 Greifswald (Germany); Princeton Plasma Physics Laboratory, PO Box 451, Princeton, New Jersey 08543 (United States); Hudson, S. R.; Bhattacharjee, A.; Lazerson, S. [Princeton Plasma Physics Laboratory, PO Box 451, Princeton, New Jersey 08543 (United States); Helander, P. [Max-Planck-Institut für Plasmaphysik, D-17491 Greifswald (Germany)


    We consider the linear and nonlinear ideal plasma response to a boundary perturbation in a screw pinch. We demonstrate that three-dimensional, ideal-MHD equilibria with continuously nested flux-surfaces and with discontinuous rotational-transform across the resonant rational-surfaces are well defined and can be computed both perturbatively and using fully nonlinear equilibrium calculations. This rescues the possibility of constructing MHD equilibria with current sheets and continuous, smooth pressure profiles. The results predict that, even if the plasma acts as a perfectly conducting fluid, a resonant magnetic perturbation can penetrate all the way into the center of a tokamak without being shielded at the resonant surface.

  5. Exotic equilibria of Harary graphs and a new minimum degree lower bound for synchronization

    KAUST Repository

    Canale, Eduardo A.


    © 2015 AIP Publishing LLC. This work is concerned with stability of equilibria in the homogeneous (equal frequencies) Kuramoto model of weakly coupled oscillators. In 2012 [R. Taylor, J. Phys. A: Math. Theor. 45, 1-15 (2012)], a sufficient condition for almost global synchronization was found in terms of the minimum degree-order ratio of the graph. In this work, a new lower bound for this ratio is given. The improvement is achieved by a concrete infinite sequence of regular graphs. Besides, non standard unstable equilibria of the graphs studied in Wiley et al. [Chaos 16, 015103 (2006)] are shown to exist as conjectured in that work.

  6. Exotic equilibria of Harary graphs and a new minimum degree lower bound for synchronization

    Energy Technology Data Exchange (ETDEWEB)

    Canale, Eduardo A., E-mail: [Facultad Politénica, UNA, Asunción (Paraguay); Monzón, Pablo, E-mail: [School of Engineering, UDELAR, Montevideo 11300 (Uruguay)


    This work is concerned with stability of equilibria in the homogeneous (equal frequencies) Kuramoto model of weakly coupled oscillators. In 2012 [R. Taylor, J. Phys. A: Math. Theor. 45, 1–15 (2012)], a sufficient condition for almost global synchronization was found in terms of the minimum degree–order ratio of the graph. In this work, a new lower bound for this ratio is given. The improvement is achieved by a concrete infinite sequence of regular graphs. Besides, non standard unstable equilibria of the graphs studied in Wiley et al. [Chaos 16, 015103 (2006)] are shown to exist as conjectured in that work.

  7. Nash equilibria in quantum games with generalized two-parameter strategies

    Energy Technology Data Exchange (ETDEWEB)

    Flitney, Adrian P. [School of Physics, University of Melbourne, Parkville VIC 3010 (Australia)]. E-mail:; Hollenberg, Lloyd C.L. [Centre for Quantum Computer Technology and School of Physics, University of Melbourne (Australia)


    In the Eisert protocol for 2x2 quantum games [J. Eisert, et al., Phys. Rev. Lett. 83 (1999) 3077], a number of authors have investigated the features arising from making the strategic space a two-parameter subset of single qubit unitary operators. We argue that the new Nash equilibria and the classical-quantum transitions that occur are simply an artifact of the particular strategy space chosen. By choosing a different, but equally plausible, two-parameter strategic space we show that different Nash equilibria with different classical-quantum transitions can arise. We generalize the two-parameter strategies and also consider these strategies in a multiplayer setting.

  8. Dark Matter Equilibria in Galaxies and Galaxy Systems (United States)

    Lapi, A.; Cavaliere, A.


    In the dark matter (DM) halos embedding galaxies and galaxy systems the "entropy" K ≡ σ2/ρ2/3 (a quantity that combines the radial velocity dispersion σ with the density ρ) is found from intensive N-body simulations to follow a power-law run K vprop r α throughout the halos' bulk, with α around 1.25. Taking up from phenomenology just that α≈ const. applies, we cut through the rich analytic contents of the Jeans equation describing the self-gravitating equilibria of the DM; we specifically focus on computing and discussing a set of novel physical solutions that we name α-profiles, marked by the entropy slope α itself, and by the maximal gravitational pull κcrit(α) required for a viable equilibrium to hold. We then use an advanced semianalytic description for the cosmological buildup of halos to constrain the values of α to within the narrow range 1.25-1.29 from galaxies to galaxy systems; these correspond to halos' current masses in the range 1011-1015 M sun. Our range of α applies since the transition time that—both in our semianalytic description and in state-of-the-art numerical simulations—separates two development stages: an early violent collapse that comprises a few major mergers and enforces dynamical mixing, followed by smoother mass addition through slow accretion. In our range of α we provide a close fit for the relation κcrit(α), and discuss a related physical interpretation in terms of incomplete randomization of the infall kinetic energy through dynamical mixing. We also give an accurate analytic representation of the α-profiles with parameters derived from the Jeans equation; this provides straightforward precision fits to recent detailed data from gravitational lensing in and around massive galaxy clusters, and thus replaces the empirical Navarro-Frenk-White formula relieving the related problems of high concentration and old age. We finally stress how our findings and predictions as to α and κcrit contribute to

  9. Correlation of Patient-Reported Outcome Measurement Information System Physical Function Upper Extremity Computer Adaptive Testing, With the American Shoulder and Elbow Surgeons Shoulder Assessment Form and Simple Shoulder Test in Patients With Shoulder Pain. (United States)

    Minoughan, Chelsea E; Schumaier, Adam P; Fritch, John L; Grawe, Brian M


    To evaluate the Patient-Reported Outcome Measurement Information System Physical Function Upper Extremity Computer Adaptive Testing (PROMIS PFUE CAT) measurement tool against the already validated American Shoulder and Elbow Surgeons Shoulder Assessment Form (ASES) and the Simple Shoulder Test (SST) in patients presenting with shoulder pain and determine the responder burden for each of the 3 surveys. Ninety patients presenting with shoulder pain were asked to fill out the ASES, SST, and PROMIS PFUE CAT. The time for completion of each survey was measured to determine responder burden, and the Pearson correlation between the 3 instruments was defined as excellent (r > 0.7), excellent-good (0.61 ≤ r ≤ 0.7), good (0.31 ≤ r ≤ 0.6), and poor (0.2 ≤ r ≤ 0.3). The PROMIS PFUE CAT showed an excellent correlation with the SST (r = 0.82, P shoulder pain. The time saving of the PROMIS PFUE CAT was found to be smaller than that of the ASES and SST but shows that moving forward, using the PROMIS PFUE CAT would not place any additional burden on the patient filling out the survey. The lack of ceiling or floor effects with the PROMIS PFUE CAT indicates its ability to differentiate both high and low functioning patients. All of these findings indicate that the PROMIS PFUE CAT is an adequate tool for the evaluation of patients with shoulder pain and should be used in these patients going forward. Level II, diagnostic study. Copyright © 2017 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

  10. Peeling-Ballooning Mode Analysis in Shifted-Circle Tokamak Equilibria (United States)

    Burke, B.; Kruger, S. E.; Hegna, C. C.; Snyder, P. B.; Sovinec, C. R.; Zhu, P.


    Progress in understanding edge localized modes (ELMs) has been made by investigating the stability properties of edge localized peeling-ballooning modes. We focus on the evolution of ideal MHD modes over a large spectrum in two shifted-circle tokamak equilibria, using the extended-MHD code NIMROD. The TOQ-generated equilibria model a H-mode plasma with a pedestal pressure profile and parallel edge currents. A vacuum region is prescribed by a resistivity profile that transitions from a small to very large value at a specified location. The vacuum model is benchmarked against the linear ideal MHD codes ELITE & GATO. We demonstrate vacuum effects on the stability by adjusting the vacuum location relative to the pedestal pressure region. Ballooning-like instabilities dominate distant vacuum cases, whereas peeling mode physics is expected to dominate as the vacuum approaches the pedestal. Numerical simulations of the early nonlinear stages of edge localized MHD instabilities are presented. Comparisons between equilibria that have ``ballooning'' dominated instabilities relative to equilibria that are ``peeling'' dominated are made.

  11. Theory of phase equilibria and critical mixing points in binary lipid bilayers

    DEFF Research Database (Denmark)

    Risbo, Jens; Sperotto, Maria Maddalena; Mouritsen, Ole G.


    The fundamental problem of determining the phase equilibria of binary mixtures is discussed in the context of two-component phospholipid bilayer membranes of saturated phospholipids with different acyl-chain lengths. Results are presented from mean-field calculations and Monte Carlo simulations o...

  12. Coalition Formation under Uncertainty: Bargaining Equilibria and the Bayesian Core Stability Concept

    NARCIS (Netherlands)

    G. Chalkiadakis (Georgios); V. Markakis (Vangelis); C. Boutillier (Cédric); E.H. Durfee; M. Yokoo; M.N. Huhns (Michael)


    textabstractCoalition formation is a problem of great interest in AI, allowing groups of autonomous, rational agents to form stable teams. Fur- thermore, the study of coalitional stability concepts and their re- lation to equilibria that guide the strategic interactions of agents during bargaining

  13. Feedback saddle point equilibria for soft-constrained zero-sum linear quadratic descriptor differential game

    NARCIS (Netherlands)

    Musthofa, M.W.; Salmah, S.; Suparwanto, A.; Engwerda, J.C.


    In this paper the feedback saddle point equilibria of soft-constrained zero-sum linear quadratic differential games for descriptor systems that have index one will be studied for a finite and infinite planning horizon. Both necessary and sufficient conditions for the existence of a feedback saddle

  14. The Representation of Highly Non-Ideal Phase Equilibria Using Computer Graphics. (United States)

    Charos, Georgios N.; And Others


    Previous work focused on use of computer graphics in teaching thermodynamic phase equilibria for classes I and II. Extends this work to include the considerably more non-ideal phase behavior shown by classes III, IV, and V. Student and instructor response has been overwhelmingly positive about the approach. (JN)

  15. Ternary liquid-liquid equilibria for mixtures of toluene + n-heptane + an ionic liquid

    NARCIS (Netherlands)

    Meindersma, G.W.; Podt, J.G.; de Haan, A.B.


    This research has been focused on a study of sulfolane and four ionic liquids as solvents in liquid–liquid extraction. Liquid–liquid equilibria data were obtained for mixtures of (sulfolane or 4-methyl-N-butylpyridinium tetrafluoroborate ([mebupy]BF4) or 1-ethyl-3-methylimidazolium ethylsulfate

  16. A numerical algorithm to find all feedback Nash equilibria in scalar affine quadratic differential games

    NARCIS (Netherlands)

    Engwerda, Jacob


    This note deals with solving scalar coupled algebraic Riccati equations. These equations arise in finding linear feedback Nash equilibria of the scalar N-player affine quadratic differential game. A numerical procedure is provided to compute all the stabilizing solutions. The main idea is to

  17. Structures and Chemical Equilibria of Some N-Heterocycles Containing Amide Linkages

    Directory of Open Access Journals (Sweden)

    N. H. Abd El Moneim


    Full Text Available Structures and chemical equilibria of 5-carboxy-2-thiouracil (1, 5,6-diphenyl-3-hydroxy-1,2,4-triazine (2, 1-phenyl-3-methyl-5-pyrazolone (3 and 2-mercapto-4,6-dimethylpyrimidine hydrochloride (4 are reported. Their electronic transitions are assigned and pK values are evaluated and discussed.

  18. Fac–mer equilibria of coordinated iminodiacetate (ida ) in ternary Cu ...

    Indian Academy of Sciences (India)


    Keywords. Fac–mer equilibria; CuII-iminodiacetate-imidazole/benzimidazole ternary complexes; stability constants. 1. Introduction. Mixed ligand complexes of transition metal ions with amino acids, peptides or their derivatives or analogues, and heterocyclic N-bases can serve as model compounds of bioinorganic interests ...

  19. Virial coefficients and vapor-liquid equilibria of the EXP6 and 2-Yukawa fluids

    Directory of Open Access Journals (Sweden)

    I. Nezbed


    Full Text Available Virial coefficients B2 through B4 and the vapor-liquid equilibria for the EXP6 and 2-Yukawa (2Y fluids have been determined using numerical integrations and Gibbs ensemble simulations, respectively. The chosen 2Y models have been recently determined as an appropriate reference fluid for the considered EXP6 models.

  20. Control Algorithms Along Relative Equilibria of Underactuated Lagrangian Systems on Lie Groups

    DEFF Research Database (Denmark)

    Nordkvist, Nikolaj; Bullo, F.


    We present novel algorithms to control underactuated mechanical systems. For a class of invariant systems on Lie groups, we design iterative small-amplitude control forces to accelerate along, decelerate along, and stabilize relative equilibria. The technical approach is based upon a perturbation...

  1. Fac–mer equilibria of coordinated iminodiacetate (ida 2–) in ternary ...

    Indian Academy of Sciences (India)

    pH potentiometric and spectrophotometric investigations on the complex formation equilibria of CuII with iminodiacetate (ida2-) and heterocyclic N-bases, viz. imidazole and benzimidazole (B), in aqueous solution in binary and ternary systems using different molar ratios of the reactants indicated the formation of complexes ...

  2. Simulation of the high-pressure phase equilibria of hydrocarbon-water/brine systems

    DEFF Research Database (Denmark)

    Zuo, You-Xiang; Stenby, Erling Halfdan; Guo, Tian-Min


    The major objectives of this work are: (1) extend the modified Patel-Teja (MPT) equation of state proposed for aqueous electrolyte systems (Zuo and Guo, 1991) to describe the liquid-liquid and vapor-liquid-liquid equilibria of hydrocarbon-water/brine systems through introducing an unconventional...

  3. Prediction of Pure Component Adsorption Equilibria Using an Adsorption Isotherm Equation Based on Vacancy Solution Theory

    DEFF Research Database (Denmark)

    Marcussen, Lis; Aasberg-Petersen, K.; Krøll, Annette Elisabeth


    An adsorption isotherm equation for nonideal pure component adsorption based on vacancy solution theory and the Non-Random-Two-Liquid (NRTL) equation is found to be useful for predicting pure component adsorption equilibria at a variety of conditions. The isotherm equation is evaluated successfully...

  4. A note on the energy of relative equilibria of point vortices

    DEFF Research Database (Denmark)

    Aref, Hassan


    Analytical formulas are derived for the energy of simple relative equilibria of identical point vortices such as the regular polygons, both open and centered, and the various known configurations consisting of nested regular polygons with or without a vortex at the center. ©2007 American Institute...

  5. Coenzyme B12 model studies: An HSAB approach to the equilibria ...

    Indian Academy of Sciences (India)

    Coenzyme B12 model studies: An HSAB approach to the equilibria and kinetics of axial ligation of alkyl(aquo)-cobaloximes by imidazole and cyanide. Vaddeboina Sridhar S Satyanarayana. Inorganic ... Keywords. Alkyl cobaloximes; association constants; hand and soft acids and bases; rhodoximes; dissociation constants.

  6. Thermodynamic modelling of phase equilibria in Al–Ga–P–As system

    Indian Academy of Sciences (India)

    A generalized thermodynamic expression of the liquid Al–Ga–P–As alloys is used in conjunction with the solid solution model in determining the solid–liquid equilibria at 1173 K and 1273 K. The liquid solution model contains thirtyseven parameters. Twentyfour of them pertain to those of the six constituent binaries, twelve ...

  7. Modeling and Experimental Studies on Phase and Chemical Equilibria in High-Pressure Methanol Synthesis

    NARCIS (Netherlands)

    van Bennekom, Joost G.; Winkelman, Jozef G. M.; Venderbosch, Robertus H.; Nieland, Sebastiaan D. G. B.; Heeres, Hero J.


    A solution method was developed to calculate the simultaneous phase and chemical equilibria in high-pressure methanol synthesis (P = 20 MPa, 463

  8. Electrostatic contributions to residue-specific protonation equilibria and proton binding capacitance for a small protein

    NARCIS (Netherlands)

    Lindman, Stina; Linse, Sara; Mulder, Frans A. A.; Andre, Ingemar


    Charge-charge interactions in proteins are important in a host of biological processes. Here we use C-13 NMR chemical shift data for individual aspartate and glutamate side chain carboxylate groups to accurately detect site-specific protonation equilibria in a variant of the B1 domain of protein G

  9. Vapor-Liquid-Solid Equilibria of Sulfur Dioxide in Aqueous Electrolyte Solutions

    DEFF Research Database (Denmark)

    Pereda, Selva; Thomsen, Kaj; Rasmussen, Peter


    The Extended UNIQUAC model for electrolyte systems, combined with the Soave-Redlich-Kwong equation of state is used to describe the complex vapor-liquid-solid equilibria of sulfur dioxide in electrolyte solutions. Model parameters based on 1500 experimental data points are presented. The parameters...

  10. Vapour–liquid equilibria of the two-and three-dimensional ...

    Indian Academy of Sciences (India)

    Vapour–liquid equilibria of the two- and three-dimensional monoatomic classical fluids interacting via double Yukawa potential. Y Pathania P K Ahluwalia. Research Articles Volume 67 Issue 6 December 2006 pp ... Keywords. Monte Carlo simulations; Gibbs ensemble; monoatomic classical fluids; double Yukawa potential.

  11. Equilibria and kinetics for pH-dependent axial ligation of alkyl (aquo ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences; Volume 114; Issue 1. Equilibria and kinetics for H-dependent axial ligation of alkyl(aquo) cobaloximes with aromatic and aliphatic N-donor ligands. V Sridhar D Sudarshan Reddy N Ravikumar Reddy S Satyanarayana. Inorganic and Analytical Volume 114 Issue 1 February ...

  12. Multiple equilibria, soil conservation investments and the resilience of agricultural systems

    NARCIS (Netherlands)

    Antle, J.M.; Stoorvogel, J.J.; Valdivia, R.O.


    This paper provides a new explanation for the persistent land degradation in some parts of the world, despite the availability of seemingly effective soil conservation technologies.We demonstrate that soil conservation technologies may induce agricultural systems to exhibit equilibria characterized

  13. Free-boundary equilibria from stellarator vacuum fields given by their boundary geometry (United States)

    Mikhailov, M. I.; Drevlak, M.; Kasilov, S. V.; Kernbichler, W.; Nemov, V. V.; Nührenberg, J.; Zille, R.


    A stellarator vacuum magnetic field determined by its last closed magnetic surface can be reconstructed by finding a remote surface-current density. Small changes of the surface-current density can then easily be made. These intermediate steps before finding a modular coil system enable free-boundary finite-β equilibria to be calculated so that their physical properties can be assessed.

  14. Phase Equilibria Impetus For Large-Volume Explosive Volcanic Eruptions (United States)

    Fowler, S. J.; Spera, F. J.; Bohrson, W. A.; Ghiorso, M. S.


    We have investigated the phase equilibria and associated variations in melt and magma thermodynamic and transport properties of seven large-volume silicic explosive volcanic systems through application of the MELTS (Ghiorso &Sack, 1995) algorithm. Each calculation is based on fractional crystallization along an oxygen buffer at low-pressure (0.1 - 0.3 GPa), starting from a mafic parental liquid. Site-specific geological constraints provide starting conditions for each system. We have performed calculations for seven tuffs; the Otowi (~400 km3) and Tshirege (~200 km3) members of the Bandelier Tuff, the ~600 km3 Bishop Tuff, and the 2500, 300, and 1000 km3 Yellowstone high-silica rhyolite tuffs. These represent the six largest eruptions within North America over the past ~2 million years. The seventh tuff, the 39.3 ka Campanian Ignimbrite, a 200 km3 trachytic to phonolitic ignimbrite located near Naples, Italy, is the largest explosive eruption in the Mediterranean area in the last 200 kyr. In all cases, MELTS faithfully tracks the liquid line of descent as well as the identity and composition of phenocrysts. The largest discrepancy between predicted and observed melt compositions is for CaO in all calculations. A key characteristic for each system is a pseudoinvariant temperature, Tinv, where abrupt shifts in crystallinity (1-fm, where fm is the fraction of melt), volume fraction of supercritical fluid (θ), magma compressibility, melt and magma density, and viscosity occur over a small temperature interval of order 1 - 10 K. In particular, the volume fraction of vapor increases from θ ~0.1 just below Tinv to θ >0.7 just above Tinv for each case. The rheological transition between melt-dominated (high viscosity) and bubble-dominated (low viscosity) magma occurs at θ ~0.6. We emphasize that this effect is observed under isobaric conditions and is distinct from the oft-studied phenomenon of volatile exsolution accompanying magma decompression and subsequent

  15. On Eulerian equilibria in K-order approximation of the gyrostat in the three-body problem

    Directory of Open Access Journals (Sweden)

    J. A. Vera


    the main result of this work, the number of Eulerian equilibria in an approximate dynamics of order k for k≥1 is independent of the order of truncation of the potential if the gyrostat S0 is close to the sphere. The instability of Eulerian equilibria is proven for any approximate dynamics if the gyrostat is close to the sphere. In this way, we generalize the classical results on equilibria of the three-body problem and many of those obtained by other authors using more classic techniques for the case of rigid bodies.

  16. Ternary liquid-liquid equilibria of dimethyl carbonate + 2-propanol + water system at 303.15 and 313.15 K (United States)

    Ginting, Rizqy Romadhona; Mustain, Asalil; Tetrisyanda, Rizki; Gunardi, Ignatius; Wibawa, Gede


    In this work, liquid-liquid equilibria data of dimethyl carbonate (DMC) + 2-propanol + water system were accurately determined at 303.15 and 313.15 K using stirred and jacketed equilibrium cell under atmospheric pressure. The reliabilities of the experimental data were confirmed using Bachman-Brown correlation giving r-squared value of 0.9993 and 0.9983 at 303.15 and 313.15 K, respectively. Experimental data obtained in this work exhibit Treybal's Type I ternary phase behavior. The selectivity and distribution coefficient of DMC increases with addition of DMC concentration in the organic phase. On the other hand, the effect of temperature to phase boundary was found to be not significant. The data were correlated well using the Non-Random Two Liquid (NRTL) and Universal Quasi-Chemical (UNIQUAC) activity coefficient models with root-mean-square deviation of 1.5% and 1.3%, respectively.

  17. Ternary (liquid + liquid) equilibria of (diethyl carbonate + ethanol or 1-propanol + water) systems at 303.15 K under atmospheric pressure (United States)

    Ginting, Rizqy Romadhona; Mustain, Asalil; Gunardi, Ignatius; Wibawa, Gede


    Ternary (liquid + liquid) equilibria data of diethyl carbonate (DEC) + ethanol or 1-propanol + water systems were accurately determined at 303.15 K using jacketed equilibrium cell under atmospheric pressure. The reliability of experimental tie-line data were checked by using Bachman-Brown correlation giving an r-squared value of 0.9933 and 0.9996, respectively. Both systems studied in this work exhibit Treybal's Type I ternary phase behavior. The experimental tie-line data were correlated well using the Non-Random Two Liquid (NRTL) and Universal Quasi-Chemical (UNIQUAC) activity coefficient models giving root-mean-square deviation (RMSD) of 0.95 and 1.18% for DEC + ethanol + water system.,While DEC + 1-propanol + water system gives RMSD value of 0.30 and 0.37%, respectively. The effect of carbon chain length of alcohol to the phase boundary of both systems was observed and discussed in detail.

  18. Vapor–liquid equilibria of triglycerides–methanol mixtures and their influence on the biodiesel synthesis under supercritical conditions of methanol

    Directory of Open Access Journals (Sweden)



    Full Text Available The non-catalytic synthesis of biodiesel (fatty acids methyl esters from triglycerides and methanol proceeds at elevated pressures above 100 bar and temperatures above 523 K. Kinetic investigations of the system revealed an unusual behavior of the reaction rate constant with increasing temperature and pressure. In order to explain this phenomenon, the phase behavior of the triglycerides–methanol mixture was investigated. The phase equilibria of the binary system sunflower oil–methanol were measured at different temperatures between 473 and 503 K, and a range of pressures between 10 and 56 bar. The experimental data were correlated using the Peng–Robinson, Soave–Redlich–Kwong and Redlich–Kwong–Aspen equations of state and different mixing rules. The best results were obtained with the RK–ASPEN equation of state and the Van derWaals mixing rule (VdW, which were then used to calculate the distribution of the phases at pressures and temperatures usual for the non-catalytic synthesis of biodiesel under high pressures. The obtained data indicated a strong influence of the phase equilibria on the reaction kinetics.

  19. Extremely Preterm Birth (United States)

    ... Education & Events Advocacy For Patients About ACOG Extremely Preterm Birth Home For Patients Search FAQs Extremely Preterm ... Pamphlets - Spanish FAQ173, June 2016 PDF Format Extremely Preterm Birth Pregnancy When is a baby considered “preterm” ...

  20. Predicting mixed-gas adsorption equilibria on activated carbon for precombustion CO2 capture. (United States)

    García, S; Pis, J J; Rubiera, F; Pevida, C


    We present experimentally measured adsorption isotherms of CO2, H2, and N2 on a phenol-formaldehyde resin-based activated carbon, which had been previously synthesized for the separation of CO2 in a precombustion capture process. The single component adsorption isotherms were measured in a magnetic suspension balance at three different temperatures (298, 318, and 338 K) and over a large range of pressures (from 0 to 3000-4000 kPa). These values cover the temperature and pressure conditions likely to be found in a precombustion capture scenario, where CO2 needs to be separated from a CO2/H2/N2 gas stream at high pressure (~1000-1500 kPa) and with a high CO2 concentration (~20-40 vol %). Data on the pure component isotherms were correlated using the Langmuir, Sips, and dual-site Langmuir (DSL) models, i.e., a two-, three-, and four-parameter model, respectively. By using the pure component isotherm fitting parameters, adsorption equilibrium was then predicted for multicomponent gas mixtures by the extended models. The DSL model was formulated considering the energetic site-matching concept, recently addressed in the literature. Experimental gas-mixture adsorption equilibrium data were calculated from breakthrough experiments conducted in a lab-scale fixed-bed reactor and compared with the predictions from the models. Breakthrough experiments were carried out at a temperature of 318 K and five different pressures (300, 500, 1000, 1500, and 2000 kPa) where two different CO2/H2/N2 gas mixtures were used as the feed gas in the adsorption step. The DSL model was found to be the one that most accurately predicted the CO2 adsorption equilibrium in the multicomponent mixture. The results presented in this work highlight the importance of performing experimental measurements of mixture adsorption equilibria, as they are of utmost importance to discriminate between models and to correctly select the one that most closely reflects the actual process.

  1. Solid-Fluid Phase Equilibria for Natural Gas Processing at Low Temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Longman


    Precipitation and deposition of solid components create potential risks of blocking gas passages in processes such as in LNG plants. To avoid such risks, experimental data and modelling of solid-fluid equilibrium should be used to optimize the design and operations. The objective of this work was to get a better understanding of the fundamentals of solid-fluid phase equilibrium. The specific focus of this work was to study solid-fluid phase behavior in systems of solid Co2, heavy hydrocarbons(HHC) and hydrate in equilibria with natural gas at low temperatures.Experimental methods for measuring solid-fluid equilibrium data in natural gas systems at low temperatures were extensively reviewed, and important and practical issues for designing experimental systems were summarized. The frost points in the Co2-methane systems (Co2 mole fraction 0.108 to 0.542) were measured in this work. Meanwhile, in another experimental setup, the water content in the gas phase was measured in the hydratemethane and hydrate-natural gas systems down to temperature 238.15 K. These data, together with data from other researchers, were used to verify the thermodynamic models. It is expensive and time-consuming to get experimental data at low temperatures, thus it is important to verify and use thermodynamic models to predict the solid-fluid phase behaviors. In the systems of solid Co2 and HHC in equilibrium with natural gas systems, the Soave-Redlich-Kwong (SRK) Equation of State (EOS) and simplified Perturbed-Chain Statistic Associating Fluid Theory (sPC-SAFT) EOS were used to calculate the fugacities in fluid phases. For solid phase, one fugacity model based on sublimation pressures and one model based on subcooled liquid were used. For correlating and predicting the hydrate behaviors, the Cubic-Plus-Association (CPA)EOS was used to model fluid phases and the hydrate-forming conditions were modelled by the solid solution theory of van der Waals and Platteeuw. Examples of applications of

  2. Phase Equilibria of H2SO4, HNO3, and HCl Hydrates and the Composition of Polar Stratospheric Clouds (United States)

    Wooldridge, Paul J.; Zhang, Renyi; Molina, Mario J.


    Thermodynamic properties and phase equilibria behavior for the hydrates and coexisting pairs of hydrates of common acids which exist in the stratosphere are assembled from new laboratory measurements and standard literature data. The analysis focuses upon solid-vapor and solid-solid-vapor equilibria at temperatures around 200 K and includes new calorimetric and vapor pressure data. Calculated partial pressures versus 1/T slopes for the hydrates and coexisting hydrates agree well with experimental data where available.

  3. Experimental investigation of phase equilibria in the Ni-Nb-V ternary system

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xingjun; Yang, Shuiyuan; Wang, Cuiping [Xiamen Univ. (China). Dept. of Materials Science and Engineering; Xiamen Univ. (China). Fujian Provincial Key Lab. of Materials Genome; Zhang, Xianjie; Jiang, Hengxing; Shi, Zhan [Xiamen Univ. (China). Dept. of Materials Science and Engineering


    The phase equilibria of the Ni-Nb-V ternary system at 1000 C and 1200 C were established using electron probe microanalysis, X-ray diffraction and differential scanning calorimetry. The results of the investigation revealed that: (1) The Nb solubility in (Ni) and σ{sup '} phases was less than 10 at.%; (2) A ternary compound τ (NiNbV) was confirmed, in which V had a large solubility; (3) A new liquid region was evident at 1200 C, but was absent at 1000 C; (4) The lattice constants of Ni{sub 3}Nb and Ni{sub 6}Nb{sub 7} phase decreased with increase in V content in the Ni{sub 3}Nb and Ni{sub 6}Nb{sub 7}. The phase equilibria of the Ni-Nb-V ternary system will contribute to its thermodynamic assessment.

  4. Analytic axisymmetric equilibria with pressure anisotropy and non-parallel flow (United States)

    Kuiroukidis, A.; Evangelias, A.; Throumoulopoulos, G. N.


    We extend previous work by two of the authors [Evangelias and Throumoulopoulos 2016 Plasma Phys. Control. Fusion 58 045022] and find analytic solutions to a generalized Grad-Shafranov equation (GGSE) with pressure anisotropy, hollow toroidal current density and incompressible flow of arbitrary direction. By specifying the surface-function terms involved in the GGSE as quadratic functions of the poloidal magnetic flux function, we derive analytic tokamak pertinent equilibria. It turns out that, irrespective of the shape of the toroidal current density profile, which is noticeably affected by the pressure anisotropy, this anisotropy has a paramagnetic effect for {p}\\parallel > {p}\\perp and a diamagnetic one for {p}\\parallel < {p}\\perp . In addition, the parallel flow induces paramagnetism, while the residual toroidal flow associated with the electric field induces diamagnetism. The analytic results obtained here contribute to the physics understanding of axisymmetric equilibria with pressure anisotropy and flow, and can be employed for validating equilibrium codes.

  5. Strategic trade between two regions with partial local consumer protection - General setup and nash equilibria (United States)

    Iordanov, Iordan V.; Vassilev, Andrey A.


    We construct a model of the trade relations between two regions for the case when the trading entities (consumers) compete for a scarce good and there is an element of strategic interdependence in the trading process. Additionally, local consumers enjoy partial protection in the form of guaranteed access to a part of the locally-supplied quantity of the good. The model is formulated for the general asymmetric case, where the two regions differ in terms of parameters such as income, size of the local market supply, degree of protection and transportation costs. For this general model we establish the existence of Nash equilibria and obtain their form as a function of the model parameters, producing a typology of the equilibria. This is a required step in order to rigorously study various types of price dynamics for the model.

  6. Thermodynamic calculations in the system CH4-H2O and methane hydrate phase equilibria (United States)

    Circone, S.; Kirby, S.H.; Stern, L.A.


    Using the Gibbs function of reaction, equilibrium pressure, temperature conditions for the formation of methane clathrate hydrate have been calculated from the thermodynamic properties of phases in the system CH4-H 2O. The thermodynamic model accurately reproduces the published phase-equilibria data to within ??2 K of the observed equilibrium boundaries in the range 0.08-117 MPa and 190-307 K. The model also provides an estimate of the third-law entropy of methane hydrate at 273.15 K, 0.1 MPa of 56.2 J mol-1 K-1 for 1/n CH4??H 2O, where n is the hydrate number. Agreement between the calculated and published phase-equilibria data is optimized when the hydrate composition is fixed and independent of the pressure and temperature for the conditions modeled. ?? 2006 American Chemical Society.

  7. Experimental determination and thermodynamic calculation of the phase equilibria in the Co-Mn-Ta system

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Cuiping; Liu, Xingjun [Xiamen Univ. (China). Dept. of Materials Science and Engineering; Xiamen Univ. (China). Research Center of Materials Design and Applications; Zhao, Cancan; Lin, Zhong [Xiamen Univ. (China). Dept. of Materials Science and Engineering


    The phase equilibria in the Co-rich corner of the Co-Mn-Ta system were investigated by means of optical microscopy, electron probe microanalysis and X-ray diffraction. Six isothermal sections in the Co-rich corner of the Co-Mn-Ta ternary system at 1300 C, 1200 C, 1100 C, 1000 C, 900 C, 800 C were experimentally determined. On the basis of previous and present experimental data of the phase equilibria, the thermodynamic assessments of the Mn-Ta binary and Co-Mn-Ta ternary systems were carried out by using CALPHAD. The thermodynamic parameters of the Mn-Ta binary and the Co-Mn-Ta ternary systems have been optimized for reproducing the experimental results in each system. An agreement between the calculated results and experimental data is obtained.

  8. Phase equilibria in water-(1-, 2-, iso-)butanol-18-crown-6 systems (United States)

    Kovalenko, N. A.; Golovina, N. B.; Bogachev, A. G.; Uspenskaya, I. A.


    We present the results from measuring the solubility of 18-crown-6 in isobutanol in the temperature interval of 280-308 K and information about liquid-liquid equilibria in water-(1-, 2-, iso-)butanol-18-crown-6 systems at 298 K. The parameter values of the extended UNIQUAC model were determined on the basis of information about the thermodynamic properties and phase equilibria in the binary systems. It is shown that we must use parameters of ternary interaction in addition to binary parameters to adequately describe the miscibility gap on the basis of the results of turbidimetric titration in ternary water-(1-,2-, iso)butanol-18-crown-6 systems.

  9. Rapidly convergent algorithms for 3-D tandem and stellarator equilibria in the paraxial approximation

    Energy Technology Data Exchange (ETDEWEB)

    McNamara, B.


    Tandem and stellarator equilibria at high ..beta.. have proved hard to compute and the relaxation methods of Bauer et al., Chodura and Schluter, Hirshman, Strauss, and Pearlstein et al. have been slow to converge. This paper reports an extension of the low-..beta.. analytic method of Pearlstein, Kaiser, and Newcomb to arbitrary ..beta.. for tandem mirrors which converges in 10 to 20 iterations. Extensions of the method to stellarator equilibria are proposed and are very close to the analytic method of Johnson and Greene - the stellarator expansion. Most of the results of all these calculations can be adequately described by low-..beta.. approximations since the MHD stability limits occur at low ..beta... The tandem mirror, having weak curvature and a long central cell, allows finite Larmor radius effects to eliminate most ballooning modes and offers the possibility of really high average ..beta... This is the interest in developing such three-dimensional numerical algorithms.

  10. Protonation Equilibria of L-Aspartic, Citric and Succinic Acids in Anionic Micellar Media

    Directory of Open Access Journals (Sweden)

    P. Srinivasa Rao


    Full Text Available The impact of sodium lauryl sulphate (SLS on the protonation equilibria of L-aspartic acid, citric acid and succinic acid has been studied in various concentrations (0.5-2.5% w/v of SLS solution maintaining an ionic strength of 0.16 mol dm-3 at 303 K. The protonation constants have been calculated with the computer program MINIQUAD75 and the best fit models have been calculated based on statistical parameters. The trend of log values of step-wise protonation constants with mole fraction of the medium has been explained based on electrostatic and non-electrostatic forces operating on the protonation equilibria. The effects of errors on the protonation constants have also been presented.

  11. (Liquid + liquid) equilibria for ternary mixtures of (alkane + benzene + [EMpy] [ESO{sub 4}]) at several temperatures and atmospheric pressure

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, Emilio J.; Calvar, Noelia; Gonzalez, Begona [Departamento de Ingenieria Quimica de la Universidad de Vigo, 36310 Vigo (Spain); Dominguez, Angeles [Departamento de Ingenieria Quimica de la Universidad de Vigo, 36310 Vigo (Spain)], E-mail:


    In this work, the separation of benzene from aliphatic hydrocarbons (hexane, or heptane) is investigated by extraction with 1-ethyl-3-methylpyridinium ethylsulphate ionic liquid, [EMpy][ESO{sub 4}]. (Liquid + liquid) equilibria (LLE) data are determined for the ternary systems: {l_brace}hexane (1) + benzene (2) + [EMpy][ESO{sub 4}] (3){r_brace} at T = (283.15, 293.15, 298.15, and 303.15) K and {l_brace}heptane (1) + benzene (2) + [EMpy][ESO{sub 4}] (3){r_brace} at T = (283.15 and 298.15) K and atmospheric pressure. The selectivity and distribution coefficient, derived from the tie line data, were used to determine whether the ionic liquid is a good solvent for the extraction of aromatic from aliphatic compounds. The consistency of the tie line data was ascertained by applying the Othmer-Tobias and Hand equations. The experimental results for the ternary systems were well correlated with the NRTL equation. A study of the temperature effect and the influence of the chain length of the alkanes were realized. The results obtained were compared with other ionic liquids. There are no literature data for the mixtures discussed in this paper.

  12. Solid-liquid Phase Equilibria of the Aqueous Systems Containing Lithium, Magnesium and Borate Ions (United States)

    Song, Yun; Zhao, Dong; Du, Xuemin; Wang, Shiqiang; Guo, Yafei; Deng, Tianlong


    It is well known that the phase chemistry is of great importance in the fields of chemistry, chemical engineering, and the separation and purification of minerals from brine. To effectively employ the resources containing lithium, magnesium and borate, the study on phase equilibrium is essential to the comprehensive utilization of the Salt Lake resources. In this paper, progresses on phase equilibria of salt-water systems containing lithium, magnesium and borate were presented.

  13. Control algorithms along relative equilibria of underactuated Lagrangian systems on Lie groups

    DEFF Research Database (Denmark)

    Nordkvist, Nikolaj; Bullo, Francesco


    We present novel algorithms to control underactuated mechanical systems. For a class of invariant systems on Lie groups, we design iterative small-amplitude control forces to accelerate along, decelerate along, and stabilize relative equilibria. The technical approach is based upon a perturbation...... analysis and the design of inversion primitives and composition methods. We illustrate the algorithms on an underactuated planar rigid body and on a satellite with two thrusters....

  14. Medium-β free-boundary equilibria of a quasi-isodynamic stellarator (United States)

    Mikhailov, M. I.; Drevlak, M.; Nührenberg, J.; Shafranov, V. D.


    Free-boundary MHD equilibria with magnetic surfaces in the vacuum region surrounding the plasma [E. Strumberger, Nucl. Fusion 37, 19 (1997); M. Drevlak, D. Monticello, and A. Reiman, Nucl. Fusion 45, 731 (2005)] are obtained for a quasi-isodynamic stellarator [A. A. Subbotin, M. I. Mikhailov, V. D. Shafranov et al., Nucl. Fusion 46, 921 (2006); M. I. Mikhailov, J. Nuhrenberg, and V. D. Shafranov, Plasma Phys. Rep. 35, 529 (2009)].

  15. Medium-{beta} free-boundary equilibria of a quasi-isodynamic stellarator

    Energy Technology Data Exchange (ETDEWEB)

    Mikhailov, M. I. [Russian Research Centre ' Kurchatov Institute,' (Russian Federation); Drevlak, M.; Nuehrenberg, J. [Teilinstitut Greifswald, Max-Planck-Institut fuer Plasmaphysik, EURATOM Association (Germany); Shafranov, V. D. [Russian Research Centre ' Kurchatov Institute,' (Russian Federation)


    Free-boundary MHD equilibria with magnetic surfaces in the vacuum region surrounding the plasma [E. Strumberger, Nucl. Fusion 37, 19 (1997); M. Drevlak, D. Monticello, and A. Reiman, Nucl. Fusion 45, 731 (2005)] are obtained for a quasi-isodynamic stellarator [A. A. Subbotin, M. I. Mikhailov, V. D. Shafranov et al., Nucl. Fusion 46, 921 (2006); M. I. Mikhailov, J. Nuhrenberg, and V. D. Shafranov, Plasma Phys. Rep. 35, 529 (2009)].

  16. Exact solutions for helical magnetohydrodynamic equilibria. II. Nonstatic and nonbarotropic solutions

    Energy Technology Data Exchange (ETDEWEB)

    Villata, M. (Istituto di Fisica Generale dell' Universita, Via Pietro Giuria 1, I-10125 Torino (Italy)); Ferrari, A. (Osservatorio Astronomico di Torino, I-10025 Pino Torinese (Italy))


    In the framework of the analytical study of magnetohydrodynamic (MHD) equilibria with flow and nonuniform density, a general family of well-behaved exact solutions of the generalized Grad--Shafranov equation and of the whole set of time-independent MHD equations completed by the nonbarotropic ideal gas equation of state is obtained, both in helical and axial symmetry. The helical equilibrium solutions are suggested to be relevant to describe the helical morphology of some astrophysical jets.

  17. Experimental investigation and thermodynamic calculation of phase equilibria in the Mg–Pb–Zn ternary system

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Dong [Department of Materials Science and Engineering, College of Materials, Xiamen University, Xiamen 361005 (China); Yang, Shuiyuan [Department of Materials Science and Engineering, College of Materials, Xiamen University, Xiamen 361005 (China); Research Center of Materials Design and Applications, Xiamen University, Xiamen 361005 (China); Liu, Xingjun [Department of Materials Science and Engineering, College of Materials, Xiamen University, Xiamen 361005 (China); Research Center of Materials Design and Applications, Xiamen University, Xiamen 361005 (China); Collaborative Innovation Center of Chemistry for Energy Materials, Xiamen University, Xiamen 361005 (China); Duh, Jenq-Gong [Department of Materials Science and Engineering, National Tsing Hua Universtiy, Hsinchu, Taiwan (China); Wang, Cuiping, E-mail: [Department of Materials Science and Engineering, College of Materials, Xiamen University, Xiamen 361005 (China); Research Center of Materials Design and Applications, Xiamen University, Xiamen 361005 (China)


    The phase equilibria of the Mg–Pb–Zn ternary system were investigated using electron probe microanalysis (EPMA), back scattered electron (BSE) imaging and X-ray diffraction (XRD) methods. Three isothermal sections of the Mg–Pb–Zn ternary system at 200 °C, 300 °C and 400 °C were experimentally established. The phase equilibria of Mg–Pb binary and Mg–Pb–Zn ternary system were thermodynamically assessed by using CALPHAD (Calculation of Phase Diagrams) method on the basis of the presently determined experimental data. A consistent set of thermodynamic parameters has been derived for describing the Gibbs free energies of each solution phase and intermetallic compound in the Mg–Pb and Mg–Pb–Zn systems. The calculated phase diagrams and thermodynamic properties in the Mg–Pb and Mg–Pb–Zn systems are in good agreement with experimental data. - Highlights: • Three isothermal sections of the Mg–Pb–Zn system were experimentally determined. • The phase equilibria of Mg–Pb binary system are thermodynamically reassessed. • The calculated phase diagrams in the Mg–Pb–Zn ternary system are in good agreement with experimental data.

  18. Evolution of phenotypic plasticity in extreme environments. (United States)

    Chevin, Luis-Miguel; Hoffmann, Ary A


    Phenotypic plasticity, if adaptive, may allow species to counter the detrimental effects of extreme conditions, but the infrequent occurrence of extreme environments and/or their restriction to low-quality habitats within a species range means that they exert little direct selection on reaction norms. Plasticity could, therefore, be maladaptive under extreme environments, unless genetic correlations are strong between extreme and non-extreme environmental states, and the optimum phenotype changes smoothly with the environment. Empirical evidence suggests that populations and species from more variable environments show higher levels of plasticity that might preadapt them to extremes, but genetic variance for plastic responses can also be low, and genetic variation may not be expressed for some classes of traits under extreme conditions. Much of the empirical literature on plastic responses to extremes has not yet been linked to ecologically relevant conditions, such as asymmetrical fluctuations in the case of temperature extremes. Nevertheless, evolved plastic responses are likely to be important for natural and agricultural species increasingly exposed to climate extremes, and there is an urgent need to collect empirical information and link this to model predictions.This article is part of the themed issue 'Behavioural, ecological and evolutionary responses to extreme climatic events'. © 2017 The Author(s).

  19. (Liquid + liquid) equilibria of (water + ethanol + dimethyl glutarate) at several temperatures[(Liquid+liquid) equilibria; Ethanol; Dimethyl glutarate; UNIFAC method

    Energy Technology Data Exchange (ETDEWEB)

    Ince, Erol. E-mail:; Kirbaslar, S. Ismail. E-mail:


    (Liquid + liquid) equilibrium (LLE) data of (water + ethanol + dimethyl glutarate) have been determined experimentally at T=(298.15,308.15 and 318.15) K. The reliability of the experimental tie-line data was ascertained by using the Othmer and Tobias correlation. The LLE data of the ternary mixture were predicted by UNIFAC method. Distribution coefficients and separation factors were evaluated for the immiscibility region.

  20. Phase equilibria in coal conversion processes. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Chao, K.C.


    Fluid-phase equilibrium data have been determined in simulation of coal liquefaction process conditions. Gas-liquid equilibrium and liquid-liquid equilibrium of water-containing mixtures have been the central interest while some water-free mixtures were also investigated. Experimental gas-liquid equilibrum studies were made for: hydrogen + water + m-cresol; hydrogen + water + quinoline; hydrogen + water + n-decane; methane + water + n-hexadecane; carbon dioxide + water + diethylamine; carbon dioxide + 1-hexadecene; carbon dioxide + n-propylcyclohexane; carbon dioxide + n-octadecane; carbon dioxide + phenyloctane; and propane + n-butyraldehyde. Mutual liquid-liquid solubilities have been determined for: water + m-cresol; water + quinoline; water + indoline; water + 1,2,3,4 - tetrahydroquinoline; water + thianaphthene; and water + 9,10 - dihydrophenanthrene. The Cubic Chain-of-Rotators (CCOR) equation of state was modified to extend to strongly polar substances. The modified equation was used to correlate the new fluid phase equilibrium data of water-containing mixtures. The original CCOR equation was used to correlate the vaporization equilibrium data of an Illinois coal liquid and a Wyoming coal liquid described in our previous report AP-3450. 107 refs., 32 figs., 19 tabs.

  1. Weather and Climate Extremes

    National Research Council Canada - National Science Library

    Krause, Paul


    .... All extremes are presented in terms of their location and date and, where supportive information is available in the professional literature, detailed discussions of the extreme event are provided...

  2. Legacy to the extreme

    NARCIS (Netherlands)

    A. van Deursen (Arie); T. Kuipers (Tobias); L.M.F. Moonen (Leon)


    textabstractWe explore the differences between developing a system using extreme programming techniques, and maintaining a legacy system. We investigate whether applying extreme programming techniques to legacy maintenance is useful and feasible.

  3. An investigation of tautomeric equilibria by means of mass spectrometry

    DEFF Research Database (Denmark)

    Zamir, Lolita; Jensen, Bror Skytte; Larsen, Elfinn


    Changes in the mass spectra with inlet temperature were used in this work to demonstrate the dependence of keto-enol tautomerism of acetylacetone, 3-methyl acetylacetone and 3-allyl acetylacetone on temperature. The largest dependence of temperature were shown by the ion [M 42]+. arising from a Mc......Lafferty type rearrangement and by the ion [M Me]+ resulting from simple -cleavage. The ion [M 42]+. peak increases with the temperature of the inlet system while the ion [M Me]+ peak decreases. By assuming that the ion [M 42]+. represents the keto form and that the ion [M Me]+ represents the cis-enol form...... (stabilized by the hydrogen bond) one sees that the direction of the intensity variation of these peaks with temperature is in accord with the expected change of keto-enol tautomerism with temperature. A quantitative correlation on the basis of the above assumptions is also approached. Recording of the mass...

  4. Extreme environment electronics

    CERN Document Server

    Cressler, John D


    Unfriendly to conventional electronic devices, circuits, and systems, extreme environments represent a serious challenge to designers and mission architects. The first truly comprehensive guide to this specialized field, Extreme Environment Electronics explains the essential aspects of designing and using devices, circuits, and electronic systems intended to operate in extreme environments, including across wide temperature ranges and in radiation-intense scenarios such as space. The Definitive Guide to Extreme Environment Electronics Featuring contributions by some of the world's foremost exp

  5. Idealized modeling of convective organization with changing sea surface temperatures using multiple equilibria in weak temperature gradient simulations (United States)

    Sentić, Stipo; Sessions, Sharon L.


    The weak temperature gradient (WTG) approximation is a method of parameterizing the influences of the large scale on local convection in limited domain simulations. WTG simulations exhibit multiple equilibria in precipitation; depending on the initial moisture content, simulations can precipitate or remain dry for otherwise identical boundary conditions. We use a hypothesized analogy between multiple equilibria in precipitation in WTG simulations, and dry and moist regions of organized convection to study tropical convective organization. We find that the range of wind speeds that support multiple equilibria depends on sea surface temperature (SST). Compared to the present SST, low SSTs support a narrower range of multiple equilibria at higher wind speeds. In contrast, high SSTs exhibit a narrower range of multiple equilibria at low wind speeds. This suggests that at high SSTs, organized convection might occur with lower surface forcing. To characterize convection at different SSTs, we analyze the change in relationships between precipitation rate, atmospheric stability, moisture content, and the large-scale transport of moist entropy and moisture with increasing SSTs. We find an increase in large-scale export of moisture and moist entropy from dry simulations with increasing SST, which is consistent with a strengthening of the up-gradient transport of moisture from dry regions to moist regions in organized convection. Furthermore, the changes in diagnostic relationships with SST are consistent with more intense convection in precipitating regions of organized convection for higher SSTs.

  6. Extreme value distributions

    CERN Document Server

    Ahsanullah, Mohammad


    The aim of the book is to give a through account of the basic theory of extreme value distributions. The book cover a wide range of materials available to date. The central ideas and results of extreme value distributions are presented. The book rwill be useful o applied statisticians as well statisticians interrested to work in the area of extreme value distributions.vmonograph presents the central ideas and results of extreme value distributions.The monograph gives self-contained of theory and applications of extreme value distributions.

  7. Petrogenesis of Mt. Baker Basalts and Andesites: Constraints From Mineral Chemistry and Phase Equilibria (United States)

    Mullen, E.; McCallum, I. S.


    Basalts in continental arcs are volumetrically subordinate to andesites and this is the case for Mt. Baker in the northern Cascade magmatic arc. However, basalts provide indirect evidence on mantle compositions and processes that produce magmas parental to the abundant andesites and dacites of the stratocones. Basalts at Mt. Baker erupted from monogenetic vents peripheral to the andesitic stratocone. Flows are variable in composition; some samples would more appropriately be classified as basaltic andesites. The “basalts” have relatively low Mg/(Mg+Fe) indicating that they have evolved from their original compositions. Samples studied are Park Butte, Tarn Plateau, Lk. Shannon, Sulphur Cr. basalts, and Cathedral Crag, Hogback, and Rankin Ridge basaltic andesites. Mt. Baker lavas belong to the calc-alkaline basalt suite (CAB) defined by Bacon et al. (1997) and preserve arc geochemical features. High alumina olivine tholeiite (HAOT) are absent. Equilibrium mineral pairs and whole rock compositions were used to calculate pre-eruptive temperatures, water contents, and redox states of the “basalts.” All samples have zoned olivine phenocrysts with Fo68 to Fo87 cores and chromite inclusions. Cpx and zoned plagioclase occur in all flows, but opx occurs only in Cathedral Crag, Rankin Ridge, and Tarn Plateau. Ti-magnetite and ilmenite coexist in all flows except for Sulphur Cr., Lk. Shannon and Hogback, which contain a single Fe-Ti oxide. Liquidus temperatures range from 1080 to 1232°C and are negatively correlated with water contents. Water contents estimated using liquidus depression due to H2O (0.8 to 5.4 wt.%) agree well with plag core-whole rock equilibria estimates (1.2 to 3.9 wt.%). Park Butte, Sulphur Cr. and Lk. Shannon had phase diagrams in the multi-component basalt system relevant to arc basalts and andesites ranging from 0 to 3 GPa and variable water contents. Projections of Mt. Baker lava compositions (corrected for loss or gain of olivine and plag

  8. Measurement of (liquid + liquid) equilibria for ternary systems of (N-formylmorpholine + benzene + cyclohexane) at temperatures (303.15, 308.15, and 313.15) K

    Energy Technology Data Exchange (ETDEWEB)

    Seyedein Ghannad, S. MohammadReza [School of Chemical, Gas and Petroleum Engineering, Semnan University, Semnan 35195-363 (Iran, Islamic Republic of); Lotfollahi, Mohammad Nader, E-mail: [School of Chemical, Gas and Petroleum Engineering, Semnan University, Semnan 35195-363 (Iran, Islamic Republic of); Haghighi Asl, Ali [School of Chemical, Gas and Petroleum Engineering, Semnan University, Semnan 35195-363 (Iran, Islamic Republic of)


    Research highlights: LLE were measured for (NFM+benzene+cyclohexane) at temperatures (303.15, 308.15 and 313.15) K. UNIQUAC and NRTL models were used to correlate the LLE. The reliability of the experimental data was tested by the Othmer-Tobias correlation. The obtained RMSDs are 0.0367 for NRTL model and 0.0539 for UNIQUAC model. - Abstract: This work demonstrates the ability of N-formylmorpholine (NFM) to act as an extraction solvent for the removal of benzene from its mixture with cyclohexane. The (liquid + liquid) equilibria (LLE) were measured for a ternary system of {l_brace}N-formylmorpholine (NFM) + benzene + cyclohexane{r_brace} under atmospheric pressure and at temperatures (303.15, 308.15, and 313.15) K. The experimental distribution coefficients (K) and selectivity factors (S) were obtained to reveal the extractive effectiveness of the solvent for separation of benzene from cyclohexane. The LLE results for the system studied indicate that increasing temperature decreases selectivity of the solvent. The reliability of the experimental results was tested by applying the Othmer-Tobias correlation. In addition, the universal quasichemical activity coefficient (UNIQUAC) and the non-random two liquids equation (NRTL) were used to correlate the LLE data using the interaction parameters determined from the experimental data. The root mean square deviations (RMSDs) obtained comparing calculated and experimental two-phase compositions are 0.0367 for the NRTL model and 0.0539 for the UNIQUAC model.

  9. Comparison of united-atom potentials for the simulation of vapor-liquid equilibria and interfacial properties of long-chain n-alkanes up to n-C100. (United States)

    Müller, Erich A; Mejía, Andrés


    Canonical ensemble molecular dynamics (MD) simulations are reported which compute both the vapor-liquid equilibrium properties (vapor pressure and liquid and vapor densities) and the interfacial properties (density profiles, interfacial tensions, entropy and enthalpy of surface formation) of four long-chained n-alkanes: n-decane (n-C(10)), n-eicosane (n-C(20)), n-hexacontane (n-C(60)), and n-decacontane (n-C(100)). Three of the most commonly employed united-atom (UA) force fields for alkanes (SKS: Smit, B.; Karaborni, S.; Siepmann, J. I. J. Chem. Phys. 1995,102, 2126-2140; J. Chem. Phys. 1998,109, 352; NERD: Nath, S. K.; Escobedo, F. A.; de Pablo, J. J. J. Chem. Phys. 1998, 108, 9905-9911; and TraPPE: Martin M. G.; Siepmann, J. I. J. Phys. Chem. B1998, 102, 2569-2577.) are critically appraised. The computed results have been compared to the available experimental data and those fitted using the square gradient theory (SGT). In the latter approach, the Lennard-Jones chain equation of state (EoS), appropriately parametrized for long hydrocarbons, is used to model the homogeneous bulk phase Helmholtz energy. The MD results for phase equilibria of n-decane and n-eicosane exhibit sensible agreement both to the experimental data and EoS correlation for all potentials tested, with the TraPPE potential showing the lowest deviations. However, as the molecular chain increases to n-hexacontane and n-decacontane, the reliability of the UA potentials decreases, showing notorious subpredictions of both saturated liquid density and vapor pressure. Based on the recommended data and EoS results for the heaviest hydrocarbons, it is possible to attest, that in this extreme, the TraPPE potential shows the lowest liquid density deviations. The low absolute values of the vapor pressure preclude the discrimination among the three UA potentials studied. On the other hand, interfacial properties are very sensitive to the type of UA potential thus allowing a differentiation of the

  10. Evolution of generalized two-dimensional magnetotail equilibria in ideal and resistive MHD (United States)

    Merkin, V. G.; Sitnov, M. I.; Lyon, J. G.


    We present results of two-dimensional (2-D) magnetohydrodynamic (MHD) simulations of the terrestrial magnetotail. A regional adaptation of the Lyon-Fedder-Mobarry global MHD model is used. As initial conditions, we employ a class of asymptotic magnetotail equilibria with and without an accumulation of magnetic flux at the tailward end (a Bz hump). The former have been recently shown by full particle simulations to be unstable to a kinetic mode with formal properties of ion tearing. Thus, our goal here is to investigate the evolution of the same equilibria in the MHD approximation and assist in the physical interpretation of the kinetic simulations. This is additionally motivated by the energy principle considerations which suggest that if the system is unstable kinetically, it may also be unstable ideally. To seek dynamical MHD regimes similar to those observed in kinetic simulations, we implement two sets of boundary conditions (velocity balanced, VB, and momentum balanced, MB), one allowing plasma flows through the boundaries and the other inhibiting such flows. The use of more reflecting MB boundary conditions results in suppression of any significant dynamics, and we see no substantial changes beyond initial equilibrium relaxation. On the other hand, VB boundary conditions allow a more efficient relaxation of initial equilibrium and absorb subsequently generated plasma flows. With these boundary conditions we find the equilibrium without a flux accumulation (i.e., with constant magnetic field component normal to the current sheet) to develop an apparently resistive mode accompanied by tailward plasma flows. At the same time, the equilibria with a Bz hump of sufficiently large amplitude develop a different, ideal, mode characterized by spontaneous generation of earthward plasma flows and an exponential growth of the corresponding electric field. This growth is qualitatively similar to the corresponding fully kinetic simulations although no explosive growth of

  11. Calculation of Liquid Water-Hydrate-Methane Vapor Phase Equilibria from Molecular Simulations

    DEFF Research Database (Denmark)

    Jensen, Lars; Thomsen, Kaj; von Solms, Nicolas


    Monte Carlo simulation methods for determining fluid- and crystal-phase chemical potentials are used for the first time to calculate liquid water-methane hydrate-methane vapor phase equilibria from knowledge of atomistic interaction potentials alone. The water and methane molecules are modeled...... potential of the zero-occupancy hydrate system using thermodynamic integration from an Einstein crystal reference state, and (iii) thermodynamic integration to obtain the water and guest molecules' chemical potentials as a function of the hydrate occupancy. The three-phase equilibrium curve is calculated...... value at corresponding conditions. While computationally intensive, simulations such as these are essential to map the thermodynamically stable conditions for hydrate systems....

  12. The Existence and Stability Analysis of the Equilibria in Dengue Disease Infection Model (United States)

    Anggriani, N.; Supriatna, A. K.; Soewono, E.


    In this paper we formulate an SIR (Susceptible - Infective - Recovered) model of Dengue fever transmission with constant recruitment. We found a threshold parameter K0, known as the Basic Reproduction Number (BRN). This model has two equilibria, disease-free equilibrium and endemic equilibrium. By constructing suitable Lyapunov function, we show that the disease- free equilibrium is globally asymptotic stable whenever BRN is less than one and when it is greater than one, the endemic equilibrium is globally asymptotic stable. Numerical result shows the dynamic of each compartment together with effect of multiple bio-agent intervention as a control to the dengue transmission.

  13. Peptide conformational equilibria computed via a single-stage shifting protocol. (United States)

    Ytreberg, F Marty; Zuckerman, Daniel M


    We study the conformational equilibria of two peptides using a novel statistical mechanics approach designed for calculating free energy differences between highly dissimilar conformational states. Our results elucidate the contrasting roles of entropy in implicitly solvated leucine dipeptide and decaglycine. The method extends earlier work by Voter and overcomes the notorious "overlap" problem in free energy computations by constructing a mathematically equivalent calculation with high conformational similarity. The approach requires only equilibrium simulations of the two states of interest, without the need for sampling transition states. We discuss possible extensions and optimizations of the approach.

  14. Phase equilibria in sugar solutions using the A-UNIFAC model


    Ferreira, Olga; Brignole, Esteban A.; Macedo, Maria E.

    2003-01-01 In this work, a modified UNIFAC model that explicitly takes into account association effects is used to describe the thermodynamic properties of phase equilibria of mixtures containing common sugars, alcohols, and water. Three main groups were defined to represent the sugars family: the sugar ring (pyranose and furanose), the osidic bond (-O-), and the ...

  15. Phase equilibria study of the binary systems (N-hexylisoquinolinium thiocyanate ionic liquid + organic solvent or water). (United States)

    Królikowska, Marta; Karpińska, Monika; Zawadzki, Maciej


    Liquid-liquid phase equilibria (LLE) of binary mixtures containing a room-temperature ionic liquid N-hexylisoquinolinium thiocyanate, [HiQuin][SCN] with an aliphatic hydrocarbon (n-hexane, n-heptane), aromatic hydrocarbon (benzene, toluene, ethylbenzene, n-propylbenzene), cyclohexane, thiophene, water, and 1-alcohol (1-ethanol, 1-butanol, 1-hexanol, 1-octanol, 1-decanol) have been determined using a dynamic method from room temperature to the boiling-point of the solvent at ambient pressure. N-hexylisoquinolinium thiocyanate, [HiQuin][SCN] has been synthesized from N-hexyl-isoquinolinium bromide as a substrate. Specific basic characterization of the new compound including NMR spectra, elementary analysis, and water content have been done. The density and viscosity of pure ionic liquid were determined over a wide temperature range from 298.15 to 348.15 K. The mutual immiscibility with an upper critical solution temperature (UCST) for the binary systems {IL + aliphatic hydrocarbon, cyclohexane, or water} was detected. In the systems of {IL + aromatic hydrocarbon or thiophene} an immiscibility gap with a lower critical solution temperature (LCST) was observed. Complete miscibility in the liquid phase, over a whole range of ionic liquid mole fraction, was observed for the binary mixtures containing IL and an 1-alcohol. For the tested binary systems with immiscibility gap {IL + aliphatic hydrocarbon, aromatic hydrocarbon, cyclohexane, thiophene, or water}, the parameters of the LLE correlation have been derived using the NRTL equation. The basic thermal properties of the pure IL, that is, the glass-transition temperature as well as the heat capacity at the glass-transition temperature, have been measured using a differential scanning microcalorimetry technique (DSC). Decomposition of the IL was detected by simultaneous thermogravimetric/differential thermal analysis (TG/DTA) experiments.

  16. Classifying Returns as Extreme

    DEFF Research Database (Denmark)

    Christiansen, Charlotte


    I consider extreme returns for the stock and bond markets of 14 EU countries using two classification schemes: One, the univariate classification scheme from the previous literature that classifies extreme returns for each market separately, and two, a novel multivariate classification scheme...... that classifies extreme returns for several markets jointly. The new classification scheme holds about the same information as the old one, while demanding a shorter sample period. The new classification scheme is useful....


    Directory of Open Access Journals (Sweden)

    P.F. Litvitsky


    Full Text Available Author brings modern conception of extreme and terminal states, their types, likenesses and differences, etiology, key common chains of pathogenesis, principles and methods of their treatment. Pathophysiological data on one of extreme states — collapse — is described in details. Next publications will present the data on shock and coma.Key words: extreme and terminal states, vicious circle of pathogenesis, extreme regulation, principles of treatment.(Voprosy sovremennoi pediatrii — Current Pediatrics. – 2010;9(3:74-80

  18. Applications of ionic liquids in biphasic separation: Aqueous biphasic systems and liquid-liquid equilibria. (United States)

    Shukla, Shashi Kant; Pandey, Shubha; Pandey, Siddharth


    Ionic liquids (ILs) have been receiving much attention in many fields of analytical chemistry because of their various interesting properties which distinguish them from volatile organic compounds. They offer both directional and non-directional forces towards a solute molecule and therefore act as excellent solvents for a wide range of polar and non-polar compounds. Because of the presence of various possible interactions, ILs easily undergo biphasic separation with water and other less polar/non-polar organic solvents. Their ability to create biphasic splitting makes them a promising candidate for liquid-liquid separation processes, such as aqueous biphasic systems and liquid-liquid equilibria. Various aspects of ILs in these separation methods are discussed in view of the origin of physical forces responsible for the biphasic interactions, the effect of structural components, temperature, pressure, pH and additives. The specific advantages of using ILs in aqueous biphasic systems and liquid-liquid equilibria in binary and ternary systems are discussed with a view to defining their future role in separation processes by giving major emphasis on developing non-toxic ILs with physical and solution properties tailored to the needs of specific sample preparation techniques. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Equilibria, information and frustration in heterogeneous network games with conflicting preferences (United States)

    Mazzoli, M.; Sánchez, A.


    Interactions between people are the basis on which the structure of our society arises as a complex system and, at the same time, are the starting point of any physical description of it. In the last few years, much theoretical research has addressed this issue by combining the physics of complex networks with a description of interactions in terms of evolutionary game theory. We here take this research a step further by introducing a most salient societal factor such as the individuals’ preferences, a characteristic that is key to understanding much of the social phenomenology these days. We consider a heterogeneous, agent-based model in which agents interact strategically with their neighbors, but their preferences and payoffs for the possible actions differ. We study how such a heterogeneous network behaves under evolutionary dynamics and different strategic interactions, namely coordination games and best shot games. With this model we study the emergence of the equilibria predicted analytically in random graphs under best response dynamics, and we extend this test to unexplored contexts like proportional imitation and scale free networks. We show that some theoretically predicted equilibria do not arise in simulations with incomplete information, and we demonstrate the importance of the graph topology and the payoff function parameters for some games. Finally, we discuss our results with the available experimental evidence on coordination games, showing that our model agrees better with the experiment than standard economic theories, and draw hints as to how to maximize social efficiency in situations of conflicting preferences.

  20. Translationally symmetric extended MHD via Hamiltonian reduction: Energy-Casimir equilibria (United States)

    Kaltsas, D. A.; Throumoulopoulos, G. N.; Morrison, P. J.


    The Hamiltonian structure of ideal translationally symmetric extended MHD (XMHD) is obtained by employing a method of Hamiltonian reduction on the three-dimensional noncanonical Poisson bracket of XMHD. The existence of the continuous spatial translation symmetry allows the introduction of Clebsch-like forms for the magnetic and velocity fields. Upon employing the chain rule for functional derivatives, the 3D Poisson bracket is reduced to its symmetric counterpart. The sets of symmetric Hall, Inertial, and extended MHD Casimir invariants are identified, and used to obtain energy-Casimir variational principles for generalized XMHD equilibrium equations with arbitrary macroscopic flows. The obtained set of generalized equations is cast into Grad-Shafranov-Bernoulli (GSB) type, and special cases are investigated: static plasmas, equilibria with longitudinal flows only, and Hall MHD equilibria, where the electron inertia is neglected. The barotropic Hall MHD equilibrium equations are derived as a limiting case of the XMHD GSB system, and a numerically computed equilibrium configuration is presented that shows the separation of ion-flow from electro-magnetic surfaces.

  1. Experimental investigation of phase equilibria in the Zr-Cu-Ni ternary system

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Mujin; Wang, Cuiping; Yang, Shuiyuan; Shi, Zhan; Han, Jiajia; Liu, Xingjun [Xiamen Univ. (China). College of Materials and Fujian Provincial Key Lab. of Materials Genome


    The phase equilibria in the Zr-Cu-Ni ternary system are investigated combined with X-ray diffraction, electron probe micro-analysis and differential scanning calorimetry. Two isothermal sections of the Zr-Cu-Ni ternary system at 1 000 C and 1 100 C are experimentally established. Most of the binary intermetallic compounds, e.g. Zr{sub 7}Ni{sub 10}, ZrNi, ZrNi{sub 5}, Zr{sub 14}Cu{sub 51}, and Zr{sub 2}Cu{sub 9}, show a remarkable ternary solubility. A new ternary compound named τ{sub 3} (Zr{sub 31.1-30.7} . Cu{sub 28.5-40.3}Ni{sub 40.4-29.0}) is detected at 1 000 C and dissolved at 1 020 C because the nearby large liquid phase field further expands. The newly determined phase equilibria will provide important information for both thermodynamic assessment and alloy design of Zr-based metallic glass.

  2. High-beta equilibria in tokamaks with pressure anisotropy and toroidal flow (United States)

    Layden, B.; Hole, M. J.; Ridden-Harper, R.


    We extend previous analytical calculations of 2D high-β equilibria in order-unity aspect ratio tokamaks with toroidal flow to include pressure anisotropy, assuming guiding-center theory for a bi-Maxwellian plasma and the ideal MHD Ohm's law. Equilibrium solutions are obtained in the core region (which fills most of the plasma volume) and the boundary layer. We find that pressure anisotropy with p∥>p⊥ ( p∥diamagnetism relative to the isotropic case whenever an equilibrium solution exists. Sufficiently fast toroidal flows ( Ω>Ωmin ) were previously found to suppress the field-free region (diamagnetic hole) that exists in static isotropic high-β equilibria. We find that all equilibrium solutions with pressure anisotropy suppress the diamagnetic hole. For the static case with a volume-averaged toroidal beta of 70%, plasmas with max (p∥/p⊥)>α1=1.07 have equilibrium solutions. We find that α1 decreases with increasing toroidal flow speed, and above the flow threshold Ωmin we find α1=1 , so that all p∥>p⊥ plasmas have equilibrium solutions. On the other hand, for p∥diamagnetic hole in the isotropic case), equilibrium solutions exist for α2p⊥ , while the converse is true for p∥

  3. Experimental vapor-liquid equilibria data for binary mixtures of xylene isomers

    Directory of Open Access Journals (Sweden)

    W.L. Rodrigues


    Full Text Available Separation of aromatic C8 compounds by distillation is a difficult task due to the low relative volatilities of the compounds and to the high degree of purity required of the final commercial products. For rigorous simulation and optimization of this separation, the use of a model capable of describing vapor-liquid equilibria accurately is necessary. Nevertheless, experimental data are not available for all binaries at atmospheric pressure. Vapor-liquid equilibria data for binary mixtures were isobarically obtained with a modified Fischer cell at 100.65 kPa. The vapor and liquid phase compositions were analyzed with a gas chromatograph. The methodology was initially tested for cyclo-hexane+n-heptane data; results obtained are similar to other data in the literature. Data for xylene binary mixtures were then obtained, and after testing, were considered to be thermodynamically consistent. Experimental data were regressed with Aspen Plus® 10.1 and binary interaction parameters were reported for the most frequently used activity coefficient models and for the classic mixing rules of two cubic equations of state.

  4. Multiple equilibria, bifurcations and selection scenarios in cosymmetric problem of thermal convection in porous medium (United States)

    Govorukhin, Vasily N.; Shevchenko, Igor V.


    We study convection in a two-dimensional container of porous material saturated with fluid and heated from below. This problem belongs to the class of dynamical systems with nontrivial cosymmetry. The cosymmetry gives rise to a hidden parameter in the system and continuous families of infinitely many equilibria, and leads to non-trivial bifurcations. In this article we present our numerical studies that demonstrate nonlinear phenomena resulting from the existence of cosymmetry. We give a comprehensive picture of different bifurcations which occur in cosymmetric dynamical systems and in the convection problem. It includes internal and external (as an invariant set) bifurcations of one-parameter families of equilibria, as well as bifurcations leading to periodic, quasiperiodic and chaotic behaviour. The existence of infinite number of stable steady-state regimes begs the important question as to which of them can realize in physical experiments. In this paper, this question (known as the selection problem) is studied in detail. In particular, we show that the selection scenarios strongly depend on the initial temperature distribution of the fluid. The calculations are carried out by the global cosymmetry-preserving Galerkin method, and numerical methods used to analyse cosymmetric systems are also described.

  5. Phases equilibria at low temperature between light hydrocarbons mixtures, methanol and water: measures and simulation

    Energy Technology Data Exchange (ETDEWEB)

    Rossilhol, N.


    In this work we discuss phase equilibria of mixtures similar to those formed during natural gas treatment (transportation and purification). The mixtures can contain light hydrocarbons (methane, ethane, propane, etc), acid gases (hydrogen sulfide, carbon dioxide), methanol (solvent, inhibitor) and (water). We present a low temperature phase equilibrium equipment to obtain two and three phase equilibrium data of light hydrocarbon-methanol-water mixtures. The realisation of the equipment, the measuring procedure and some determination of binary, ternary and quaternary systems are described. The range of application is - 100 deg. C to 0 deg. C in temperature and between 0 and 100 bar in pressure. The binary subsystems of the systems mentioned above are calculated in order to study the possibilities of the MHV2 and Wong and Sandler methods to represent simultaneously their vapor-liquid and liquid-liquid equilibria. According to the formalism proposed by the two methods, the cubic Soave-Redlich-Kwong equation of state is systematically combined with the NRTL excess Gibbs energy model. (authors). 72 refs., 47 figs., 38 tabs.

  6. Characterizing the Nash equilibria of a three-player Bayesian quantum game (United States)

    Solmeyer, Neal; Dixon, Ricky; Balu, Radhakrishnan


    Quantum games with incomplete information can be studied within a Bayesian framework. We consider a version of prisoner's dilemma (PD) in this framework with three players and characterize the Nash equilibria. A variation of the standard PD game is set up with two types of the second prisoner and the first prisoner plays with them with probability p and 1-p, respectively. The Bayesian nature of the game manifests in the uncertainty that the first prisoner faces about his opponent's type which is encoded either in a classical probability or in the amplitudes of a wave function. Here, we consider scenarios with asymmetric payoffs between the first and second prisoner for different values of the probability, p, and the entanglement. Our results indicate a class of Nash equilibria (NE) with rich structures, characterized by a phase relationship on the strategies of the players. The rich structure can be exploited by the referee to set up rules of the game to push the players toward a specific class of NE. These results provide a deeper insight into the quantum advantages of Bayesian games over their classical counterpart.

  7. GPU.proton.DOCK: Genuine Protein Ultrafast proton equilibria consistent DOCKing. (United States)

    Kantardjiev, Alexander A


    GPU.proton.DOCK (Genuine Protein Ultrafast proton equilibria consistent DOCKing) is a state of the art service for in silico prediction of protein-protein interactions via rigorous and ultrafast docking code. It is unique in providing stringent account of electrostatic interactions self-consistency and proton equilibria mutual effects of docking partners. GPU.proton.DOCK is the first server offering such a crucial supplement to protein docking algorithms--a step toward more reliable and high accuracy docking results. The code (especially the Fast Fourier Transform bottleneck and electrostatic fields computation) is parallelized to run on a GPU supercomputer. The high performance will be of use for large-scale structural bioinformatics and systems biology projects, thus bridging physics of the interactions with analysis of molecular networks. We propose workflows for exploring in silico charge mutagenesis effects. Special emphasis is given to the interface-intuitive and user-friendly. The input is comprised of the atomic coordinate files in PDB format. The advanced user is provided with a special input section for addition of non-polypeptide charges, extra ionogenic groups with intrinsic pK(a) values or fixed ions. The output is comprised of docked complexes in PDB format as well as interactive visualization in a molecular viewer. GPU.proton.DOCK server can be accessed at

  8. NMR studies of the equilibria and reaction rates in aqueous solutions of formaldehyde. (United States)

    Rivlin, Michal; Eliav, Uzi; Navon, Gil


    Formaldehyde has an important role in the chemical industry and in biological sciences. In dilute aqueous solutions of formaldehyde only traces of the molecular formaldehyde are present and the predominant species are methylene glycol and in lower concentrations, dimethylene glycol. The chemical equilibria and reaction rates of the hydration of formaldehyde in H2O and D2O solutions at low concentrations were studied by (1)H and (13)C NMR at various conditions of pH (1.8-7.8) and temperature (278-333 K). These measurements became possible by direct detection of formaldehyde (13)C and (1)H peaks. The equilibrium and rate constants of the dimerization reaction of methylene glycol were also measured. The rate constants for both the hydration and the dimerization reactions were measured by a new version of the conventional selective inversion transfer method. This study, together with previous published work, completes the description of dynamics and equilibria of all the processes occurring in dilute aqueous formaldehyde solutions.

  9. Surface currents on the plasma-vacuum interface in MHD equilibria (United States)

    Hanson, James


    The VMEC non-axisymmetric MHD equilibrium code can compute free-boundary equilibria. Since VMEC assumes that magnetic fields within the plasma form closed and nested flux surfaces, the plasma-vacuum interface is a flux surface, and the total magnetic field there has no normal component. VMEC imposes this condition of zero normal field using the potential formulation of Merkel, and solves a Neumann problem for the magnetic potential in the exterior region. This boundary condition necessarily admits the possibility of a surface current on the interface. While this surface current may be small in MHD equilibrium, it is readily computed in terms of the magnetic potentials in both the interior and exterior regions, evaluated on the surface. If only the external magnetic potential is known (as in VMEC), then the surface current can be computed from the discontinuity of the tangential field across the interface. Examples of the surface current for VMEC equilibria will be shown for a zero-pressure stellarator equilibrium. Field-line following of the vacuum magnetic field shows magnetic islands within the plasma region.

  10. A Hierarchy of Dynamic Equilibria and a View of a Fly's Equilibrium Reflex (United States)

    Wang, Z. Jane

    Understanding structures within a structure is a topic that has fascinated Leo throughout his life, and we are now benefiting from his fundamental insights when we think about living organisms. A living organism is far from statistical equilibrium and it does not have a single critical parameter. Nevertheless, each organism has a hierarchical structure within itself. Recently, asking how often a fly must sense its orientation in order to balance in air has led us to suggest one of the fly's 17 steering muscles, the first basalar muscle, is responsible for maintaining flight stability. Here I suggest that the chain of events associated with flight equilibrium reflex can be viewed as a succession of local linear transformation about a set of dynamic equilibria. Each of the functionally different parts, the sensors, motor neurons, muscles, wing-hinges, flapping wings, and the thorax, operates near its own dynamic equilibrium, often close to the boundary between stability and instability. Locomotion rises as an organism responds to a small perturbation from these equilibria. Kadanoff session.

  11. Extreme events in Faraday waves (United States)

    Punzmann, Horst; Shats, Michael; Xia, Hua


    Observations of extreme wave events in the ocean are rare due to their low statistical probability. In the laboratory however, the evolution of extreme wave events can be studied in great detail with high spatial and temporal resolution. The reported surface wave experiments in the short wavelength gravity-capillary range aim to contribute to the understanding of some of the underlying mechanisms for rogue wave generation. In this talk, we report on extreme wave events in parametrically excited Faraday waves. Faraday waves appear if a fluid is accelerated (normal to the fluid surface) above a critical threshold. A variety of novel tools have been deployed to characterize the 2D surface elevation. The results presented show spatio-temporal and statistical data on the surface wave conditions leading up to extreme wave events. The peak in wave amplitude during such an event is shown to exceed six times the standard deviation of the average wave field with significantly increased statistical probability compared to the background wave field [1]. The experiments also show that parametrically excited waves can be viewed as assembles of oscillons [2] (or oscillating solitons) where modulation instability seems to play a crucial role in their formation. More detailed studies on the oscillon dynamics reveal that the onset of an increased probability of extreme wave events correlates with the increase in the oscillons mobility and merger [3]. Reference: 1. Xia H., Maimbourg T., Punzmann H., and Shats M., Oscillon dynamics and rogue wave generation in Faraday surface ripples, Physical Review Letters 109, 114502 (2012) 2. Shats M., Xia H., and Punzmann H., Parametrically excited water surface ripples as ensembles of oscillons, Physical Review Letters 108, 034502 (2012) 3. Shats M., Punzmann H., Xia H., Capillary rogue waves, Physical Review Letters, 104, 104503 (2010)

  12. Toward an understanding of the salting-out effects in aqueous ionic liquid solutions: vapor-liquid equilibria, liquid-liquid equilibria, volumetric, compressibility, and conductivity behavior. (United States)

    Sadeghi, Rahmat; Mostafa, Bahar; Parsi, Elham; Shahebrahimi, Yasaman


    The action of particular electrolytes in altering the solution properties of ionic liquids is well documented, although the origin of this effect is not clearly defined. In order to clarify this point, the aim of this work is to obtain further evidence about the salting-out effect produced by the addition of different salts to aqueous solutions of water miscible ionic liquids by evaluating the effect of a large series of salts on the vapor-liquid equilibria, liquid-liquid phase diagram, volumetric, compressibility, and conductometric properties of ionic liquids 1-alkyl-3-methylimidazolium halide ([C(n)mim][X]). In the first part of this work, the experimental measurements of water activity at 298.15 and 308.15 K for aqueous binary and ternary solutions containing 1-alkyl-3-methylimidazolium bromide ([Rmim][Br], R = butyl (C(4)), heptyl (C(7)), and octyl (C(8))), sodium dihydrogen citrate (NaH(2)Cit), disodium hydrogen citrate (Na(2)HCit), and trisodium citrate (Na(3)Cit) are taken using both vapor pressure osmometry (VPO) and improved isopiestic methods. The effect of temperature, charge on the anion of sodium citrate salts, and alkyl chain length of ionic liquids on the vapor-liquid equilibria properties of the investigated systems are studied. The constant water activity lines of all the ternary systems show large negative deviation from the linear isopiestic relation (Zdanovskii-Stokes-Robinson rule) derived using the semi-ideal hydration model, and the vapor pressure depression for a ternary solution is much larger than the sum of those for the corresponding binary solutions with the same molality of the ternary solution. The results have been interpreted in terms of the solute-water and solute-solute interactions. In the second part of this work, the effects of the addition of (NH(4))(3)Cit, K(3)Cit, Na(3)Cit, (NH(4))(2)HPO(4), and (NH(4))(3)PO(4) on the liquid-liquid phase diagram, apparent molar volume, isentropic compressibility, and conductivity of aqueous

  13. Quantifying the relationship between extreme air pollution events and extreme weather events (United States)

    Zhang, Henian; Wang, Yuhang; Park, Tae-Won; Deng, Yi


    Extreme weather events can strongly affect surface air quality, which has become a major environmental factor to affect human health. Here, we examined the relationship between extreme ozone and PM2.5 (particular matter with an aerodynamic diameter less than 2.5 μm) events and the representative meteorological parameters such as daily maximum temperature (Tmax), minimum relative humidity (RHmin), and minimum wind speed (Vmin), using the location-specific 95th or 5th percentile threshold derived from historical reanalysis data (30 years for ozone and 10 years for PM2.5). We found that ozone and PM2.5 extremes were decreasing over the years, reflecting EPA's tightened standards and effort on reducing the corresponding precursor's emissions. Annual ozone and PM2.5 extreme days were highly correlated with Tmax and RHmin, especially in the eastern U.S. They were positively (negatively) correlated with Vmin in urban (rural and suburban) stations. The overlapping ratios of ozone extreme days with Tmax were fairly constant, about 32%, and tended to be high in fall and low in winter. Ozone extreme days were most sensitive to Tmax, then RHmin, and least sensitive to Vmin. The majority of ozone extremes occurred when Tmax was between 300 K and 320 K, RHmin was less than 40%, and Vmin was less than 3 m/s. The number of annual extreme PM2.5 days was highly positively correlated with the extreme RHmin/Tmax days, with correlation coefficient between PM2.5/RHmin highest in urban and suburban regions and the correlation coefficient between PM2.5/Tmax highest in rural area. Tmax has more impact on PM2.5 extreme over the eastern U.S. Extreme PM2.5 days were more likely to occur at low RH conditions in the central and southeastern U.S., especially during spring time, and at high RH conditions in the northern U.S. and the Great Plains. Most extreme PM2.5 events occurred when Tmax was between 300 K and 320 K and RHmin was between 10% and 50%. Extreme PM2.5 days usually occurred when

  14. Binary, ternary and quaternary liquid-liquid equilibria in 1-butanol, oleic acid, water and n-heptane mixtures

    NARCIS (Netherlands)

    Winkelman, J. G. M.; Kraai, G. N.; Heeres, H. J.


    This work reports on liquid-liquid equilibria in the system 1-butanol, oleic acid, water and n-heptane used for biphasic, lipase catalysed esterifications. The literature was studied on the mutual solubility in binary systems of water and each of the organic components. Experimental results were

  15. Numerical analysis of Markov-perfect equilibria with multiple stable steady states : A duopoly application with innovative firms

    NARCIS (Netherlands)

    Dawid, H.; Keoula, M.Y.; Kort, Peter


    This paper presents a numerical method for the characterization of Markov-perfect equilibria of symmetric differential games exhibiting coexisting stable steady states. The method relying on the calculation of ‘local value functions’ through collocation in overlapping parts of the state space, is

  16. Adsorption of halogenated hydrocarbons from aqueous solutions by wetted and non-wetted hydrophobic and hydrophilic sorbents: equilibria

    NARCIS (Netherlands)

    Rexwinkel, Glenn; Rexwinkel, G.; Heesink, Albertus B.M.; van Swaaij, Willibrordus Petrus Maria


    Single-solute adsorption equilibria of 1,1,1-trichloroethane, 1,1,2-trichloroethane, trichloroethene, trans-1,2-dichloroethene, chloroform, 2,4-dichorophenol, and dichloromethane dissolved in water have been measured, using both wetted and nonwetted hydrophobic Amberlite XAD-4 resin at 20 °C. The

  17. Modeling the vapor-liquid equilibria of polymer-solvent mixtures: Systems with complex hydrogen bonding behavior

    DEFF Research Database (Denmark)

    Tsivintzelis, Ioannis; Kontogeorgis, Georgios


    The vapor–liquid equilibria of binary polymer–solvent systems was modeled using the Non-Random Hydrogen Bonding (NRHB) model. Mixtures of poly(ethylene glycol), poly(propylene glycol), poly(vinyl alcohol) and poly(vinyl acetate) with various solvents were investigated, while emphasis was put on h...


    Directory of Open Access Journals (Sweden)

    Süheyla ÇEHRELİ


    Full Text Available The liquid-liquid equilibria of Water-Propionic Acid-Benzyl Alcohol, Water-Propionic Acid-Benzyl Acetate and Water-Propionic Acid-Dibenzyl Ether ternary systems were predicted by means of UNIFAC Model. For this purpose, multivariable Newton-Raphson convergence procedure was used. Experimental and model results were compared.

  19. (Liquid plus liquid) equilibria of binary polymer solutions using a free-volume UNIQUAC-NRF model

    DEFF Research Database (Denmark)

    Radfarnia, H.R.; Ghotbi, C.; Taghikhani, V.


    + liquid) equilibria (LLE) for a number of binary polymer solutions at various temperatures. The values for the binary characteristic energy parameters for the proposed model and the FV-UNIQUAC model along with their average relative deviations from the experimental data were reported. It should be stated...

  20. Response Timescales and Multiple Equilibria in Boundary-Layer Cloud-Aerosol Interaction (United States)

    Bretherton, C. S.; Berner, A.; Wood, R.


    Large-eddy simulations (LES) of subtropical stratocumulus-topped boundary layers coupled to an interactive aerosol model are run for multiday periods to examine their coupled equilibria and adjustment timescales. The LES includes two-moment Morrison microphysics, interactive radiation, and Razzak-Ghan cloud droplet activation from a single log-normal size distribution of hygroscopic aerosol with prognosed total aerosol mass and number. The aerosol evolves due to surface and entrainment sources, dry coalescence, precipitation sinks coupled to the Morrison microphysics due to autoconversion and accretion of cloud droplets (and a source due to raindrop evaporation), and cloud and rain scavenging of interstitial aerosol. Simulations are initialized with an idealized southeast Pacific stratocumulus sounding based on observations during VOCALS REx and forced with specified SST, mean subsidence, geostrophic wind, and free-tropospheric aerosol concentration. The surface aerosol source is based on the Clarke parameterization for the dependence of sea-salt number concentration on wind speed. Both surface and free-tropospheric aerosol are assumed to quickly grow to a specified size due to a surface DMS source. The goal is to explore the adjustment timescales and long-term equilibria produced by this model, to compare with studies such as Wood et al. (2012) that postulate that remote marine boundary layer aerosol concentrations are controlled as much by the precipitation sink as the surface and entrainment sources. We show that the coupled cloud-aerosol model supports rapid transitions from a solid, high aerosol, stratocumulus-capped state to a cumulus-like state reminisniscent of pockets of open cells as the liquid water path rises above a threshold supporting sufficient precipitation. The system can support multiple long-term equilibria for the same boundary forcing, or slow oscillations between a collapsed POC-like state and a deepening, thickening stratocumulus

  1. Phase Equilibria Modeling of Coesite Eclogite from the Sulu Belt, Eastern China (United States)

    Xia, B.; Brown, M.; Wang, L.; Wang, S.; Piccoli, P. M.


    Modeling of phase equilibria and tectonic processes are essential components to understand controls on P-T paths of UHPM rocks. However, diffusion at higher temperatures (> 700 °C), and issues with determination of Fe3+ in minerals and estimating H2O contents limit our ability to determine prograde, peak P and retrograde P-T data. Also, the lack of an appropriate activity-composition model for melt in basic rocks has limited the application of phase equilibria modeling to understand partial melting associated with exhumation. Here we apply phase equilibria modeling to coesite eclogite from Yangkou to assess the influence of Fe3+ and fluid during metamorphism, monitor reactions and phase relations in eclogite during deep subduction and exhumation and investigate partial melting at HP conditions. The modeling used the THERMOCALC software and the new internally consistent thermodynamic dataset for basic rocks ( Here we investigate bimineralic (gt+omp+coe/qz+ru/ilm), phengite-bearing (gt+omp+phen (2 samples, 5 vol%) +coe/qz+ru/ilm) and kyanite-bearing (gt+omp+phen+ky+coe/qz+ru/ilm) eclogites. Coesite in the matrix is the hallmark of the Yangkou eclogite. For each sample, we use an iterative process to estimate the H2O and O content in the bulk composition, and then calculate a P-T pseudosection. The results suggest that some prograde information (670-770 °C, > 3.0 GPa) is retained in large garnet cores in bimineralic and phengite-bearing eclogite. The peak P-T conditions are a challenge because in the field of gt+omp+coe/qz±phen+H2O at T > 750 °C and P > 3.5 GPa mode and compositional changes are small. However, isopleths of Si in phengite suggest that the peak P could have been > 5-6 GPa. Re-equilibration of garnet and omphacite compositions occurred during exhumation, yielding P-T conditions of 700-790 °C at 3.1-2.0 GPa. Amphibolite facies metamorphism occurred at 630-710 °C, 1.3-1.2 GPa. The

  2. Analysis of extreme events

    CSIR Research Space (South Africa)

    Khuluse, S


    Full Text Available ) determination of the distribution of the damage and (iii) preparation of products that enable prediction of future risk events. The methodology provided by extreme value theory can also be a powerful tool in risk analysis...

  3. Extreme bosonic linear channels (United States)

    Holevo, A. S.


    The set of all channels with a fixed input and output is convex. We first give a convenient formulation of the necessary and sufficient condition for a channel to be an extreme point of this set in terms of the complementary channel, a notion of great importance in quantum information theory. This formulation is based on the general approach to extremality of completely positive maps in an operator algebra in the spirit of Arveson. We then use this formulation to prove our main result: under certain nondegeneracy conditions, environmental purity is necessary and sufficient for the extremality of a bosonic linear (quasifree) channel. It hence follows that a Gaussian channel between finite-mode bosonic systems is extreme if and only if it has minimum noise.

  4. Extreme environments and exobiology (United States)

    Friedmann, E. I.


    Ecological research on extreme environments can be applied to exobiological problems such as the question of life on Mars. If life forms (fossil or extant) are found on Mars, their study will help to solve fundamental questions about the nature of life on Earth. Extreme environments that are beyond the range of adaptability of their inhabitants are defined as "absolute extreme". Such environments can serve as terrestrial models for the last stages of life in the history of Mars, when the surface cooled down and atmosphere and water disappeared. The cryptoendolithic microbial community in porous rocks of the Ross Desert in Antarctica and the microbial mats at the bottom of frozen Antarctic lakes are such examples. The microbial communities of Siberian permafrost show that, in frozen but stable communities, long-term survival is possible. In the context of terraforming Mars, selected microorganisms isolated from absolute extreme environments are considered for use in creation of a biological carbon cycle.


    Energy Technology Data Exchange (ETDEWEB)



    OAK-B135 The pressure profile and plasma shape, parameterized by elongation ({kappa}), triangularity ({delta}), and squareness ({zeta}), strongly influence stability. In this study, ideal stability of single null and symmetric, double-null, advanced tokamak (AT) configurations is examined. All the various shapes are bounded by a common envelope and can be realized in the DIII-D tokamak. The calculated AT equilibria are characterized by P{sub 0}/

    {approx} 2.0-4.5, weak negative central shear, high q{sub min} (> 2.0), high bootstrap fraction, an H-mode pedestal, and varying shape parameters. The pressure profile is modeled by various polynomials together with a hyperbolic tangent pedestal, consistent with experimental observations. Stability is calculated with the DCON code and the resulting stability boundary is corroborated by GATO runs.

  6. Effect of Profiles and Space on Ideal Stability of Advanced Tokamak Equilibria

    Energy Technology Data Exchange (ETDEWEB)

    Makowski, M A; Casper, T A; Ferron, J R; Taylor, T S; Turnbull, A D


    The pressure profile and plasma shape, parameterized by elongation ({kappa}), triangularity ({delta}), and squareness ({zeta}), strongly influence stability. In this study, ideal stability of single null and symmetric, double-null, advanced tokamak (AT) configurations is examined. All the various shapes are bounded by a common envelope and can be realized in the DIII-D tokamak. The calculated AT equilibria are characterized by P{sub 0}/{l_angle}P{r_brace} {approx} 2.0-4.5, weak negative central shear, high q{sub min} (>2.0), high bootstrap fraction, an H-mode pedestal, and varying shape parameters. The pressure profile is modeled by various polynomials together with a hyperbolic tangent pedestal, consistent with experimental observations. Stability is calculated with the DCON code and the resulting stability boundary is corroborated by GATO runs.

  7. High-pressure fluid-phase equilibria: Experimental methods and systems investigated (2005-2008)

    DEFF Research Database (Denmark)

    Fonseca, José; Dohrn, Ralf; Peper, Stephanie


    %) have carbon dioxide as one of the components. Information on 206 pure components, 535 ternary systems of which 355 (66%) contain carbon dioxide, 163 multicomponent and complex systems, and 207 systems with hydrates is given. A continuation of the review series is planned, covering the years from 2009......A review of systems is given, for which experimental high-pressure phase-equilibrium data were published in the period between 2005 and 2008, continuing a series of reviews. To find candidates for articles that are of interest for this survey a three-stage search strategy was used including...... a systematic search of the contents of the 17 most important journals of the field. Experimental methods for the investigation of high-pressure phase equilibria were classified, described and illustrated using examples from articles of the period between 2005 and 2008. For the systems investigated...

  8. Prediction of phase equilibria in the In–Sb–Pb system

    Directory of Open Access Journals (Sweden)



    Full Text Available Binary thermodynamic data, successfully used for phase diagram calculations of the binary systems In–Sb, Pb–Sb and In–Pb, were used for the prediction of the phase equilibria in the ternary In–Sb–Pb system. The predicted equilibrium phase diagram of the vertical Pb–InSb section was compared with the results of differential thermal analysis DTA and optical microscopy. The calculated phase diagram of the isothermal section at 300 °C was compared with the experimentally (SEM, EDX determined composition of phases in the chosen alloys after annealing. Very good agreement between the binary-based thermodynamic prediction and the experimental data was found in all cases. The calculated liquidus projection of the ternary In–Sb–Pb system is also presented.

  9. Magnetic islands and singular currents at rational surfaces in three-dimensional magnetohydrodynamic equilibria

    Energy Technology Data Exchange (ETDEWEB)

    Loizu, J., E-mail: [Max-Planck-Institut für Plasmaphysik, D-17491 Greifswald (Germany); Princeton Plasma Physics Laboratory, P.O. Box 451, Princeton New Jersey 08543 (United States); Hudson, S.; Bhattacharjee, A. [Princeton Plasma Physics Laboratory, P.O. Box 451, Princeton New Jersey 08543 (United States); Helander, P. [Max-Planck-Institut für Plasmaphysik, D-17491 Greifswald (Germany)


    Using the recently developed multiregion, relaxed MHD (MRxMHD) theory, which bridges the gap between Taylor's relaxation theory and ideal MHD, we provide a thorough analytical and numerical proof of the formation of singular currents at rational surfaces in non-axisymmetric ideal MHD equilibria. These include the force-free singular current density represented by a Dirac δ-function, which presumably prevents the formation of islands, and the Pfirsch-Schlüter 1/x singular current, which arises as a result of finite pressure gradient. An analytical model based on linearized MRxMHD is derived that can accurately (1) describe the formation of magnetic islands at resonant rational surfaces, (2) retrieve the ideal MHD limit where magnetic islands are shielded, and (3) compute the subsequent formation of singular currents. The analytical results are benchmarked against numerical simulations carried out with a fully nonlinear implementation of MRxMHD.

  10. Construction of Subgame-Perfect Mixed-Strategy Equilibria in Repeated Games

    Directory of Open Access Journals (Sweden)

    Kimmo Berg


    Full Text Available This paper examines how to construct subgame-perfect mixed-strategy equilibria in discounted repeated games with perfect monitoring. We introduce a relatively simple class of strategy profiles that are easy to compute and may give rise to a large set of equilibrium payoffs. These sets are called self-supporting sets, since the set itself provides the continuation payoffs that are required to support the equilibrium strategies. Moreover, the corresponding strategies are simple as the players face the same augmented game on each round but they play different mixed actions after each realized pure-action profile. We find that certain payoffs can be obtained in equilibrium with much lower discount factor values compared to pure strategies. The theory and the concepts are illustrated in 2 × 2 games.

  11. Simulated annealing for three-dimensional low-beta reduced MHD equilibria in cylindrical geometry

    CERN Document Server

    Furukawa, M


    Simulated annealing (SA) is applied for three-dimensional (3D) equilibrium calculation of ideal, low-beta reduced MHD in cylindrical geometry. The SA is based on the theory of Hamiltonian mechanics. The dynamical equation of the original system, low-beta reduced MHD in this study, is modified so that the energy changes monotonically while preserving the Casimir invariants in the artificial dynamics. An equilibrium of the system is given by an extremum of the energy, therefore SA can be used as a method for calculating ideal MHD equilibrium. Previous studies demonstrated that the SA succeeds to lead to various MHD equilibria in two dimensional rectangular domain. In this paper, the theory is applied to 3D equilibrium of ideal, low-beta reduced MHD. An example of equilibrium with magnetic islands, obtained as a lower energy state, is shown. Several versions of the artificial dynamics are developed that can effect smoothing.

  12. Studies on (acid + base) equilibria in substituted (phenol + n-butylamine) systems in acetonitrile

    Energy Technology Data Exchange (ETDEWEB)

    Kozak, A. [Department of General Chemistry, University of Gdansk, Sobieskiego 18, 80-952 Gdansk (Poland); Czaja, M. [Department of General Chemistry, University of Gdansk, Sobieskiego 18, 80-952 Gdansk (Poland); Chmurzynski, L. [Department of General Chemistry, University of Gdansk, Sobieskiego 18, 80-952 Gdansk (Poland)]. E-mail:


    (Acid + base) equilibria, including molecular heteroconjugation ones, between n-butylamine and one of the following phenols: 2-nitrophenol, 3-nitrophenol, 4-nitrophenol, 2,4-dinitrophenol, 2,5-dinitrophenol, 3-chlorophenol, 4-chlorophenol, 2,3,4,5,6-pentachlorophenol and 2,4,6-tribromophenol have been studied potentiometrically in a protophobic polar aprotic solvent, acetonitrile. Among the phenols studied, 2,5-dinitrophenol exhibited the strongest tendency towards formation of asymmetric hydrogen bonds with n-butylamine, whereas a weakest complex was formed with 2-nitrophenol. In the (n-butylamine + 2,3,4,5,6-pentachlorophenol) and (n-butylamine + 2,4-dinitrophenol) systems proton transfer reactions occurred.

  13. Phase equilibria investigation and alloys characterization in Sn-In-Ag system

    Directory of Open Access Journals (Sweden)

    Milosavljević Aleksandra R.


    Full Text Available Lead-free soldering has become very popular in the world recently, especially in electronics, because of high ecological demands in industry. Some of lead-free solder alloys are already used in electronic industry, but despite that investigations are still going in order to find suitable replacement for Pb-Sn standard solder. In this paper phase equilibria and characterization of Sn-In-Ag alloys in section In:Ag = 7:3 are investigated. The results of phase diagram calculation are obtained by ThermoCalc software, and characteristic temperatures by DSC method. The results of XRD analysis, optical microscopy, microhardness and electrical conductivity are also presented. These results are given in order to contribute the knowledge about lead-free solders, especially Sn-In-Ag solder alloys, which are potential candidates for replacement standard lead solders.

  14. Melt-gas phase equilibria and state diagrams of the selenium-tellurium system (United States)

    Volodin, V. N.; Trebukhov, S. A.; Burabaeva, N. M.; Nitsenko, A. V.


    The partial pressures of saturated vapor of the components in the Se-Te system are determined and presented in the form of temperature-concentration dependences from which the boundaries of the melt-gas phase transition are calculated at atmospheric pressure and vacuums of 2000 and 100 Pa. The existence of azeotropic mixtures is revealed. It is found that the points of inseparably boiling melts correspond to 7.5 at % of Se and 995°C at 101325 Pa, 10.9 at % at 673°C and 19.5 at % at 522°C in vacuums of 2000 and 100 Pa, respectively. A complete state diagram is constructed, including the fields of gas-liquid equilibria at atmospheric and low pressures, the boundaries of which allow us to assess the behavior of selenium and tellurium upon distillation fractionation.

  15. Calculating Pressure-Driven Current Near Magnetic Islands for 3D MHD Equilibria (United States)

    Radhakrishnan, Dhanush; Reiman, Allan


    In general, 3D MHD equilibria in toroidal plasmas do not result in nested pressure surfaces. Instead, islands and chaotic regions appear in the equilibrium. Near small magnetic islands, the pressure varies within the flux surfaces, which has a significant effect on the pressure-driven current, introducing singularities. Previously, the MHD equilibrium current near a magnetic island was calculated, including the effect of ``stellarator symmetry,'' wherein the singular components of the pressure-driven current vanish [A. H. Reiman, Phys. Plasmas 23, 072502 (2016)]. Here we first solve for pressure in a cylindrical plasma from the heat diffusion equation, after adding a helical perturbation. We then numerically calculate the corresponding Pfirsch-Schluter current. At the small island limit, we compare the pressure-driven current with the previously calculated solution, and far from the island, we recover the solution for nested flux surfaces. Lastly, we compute the current for a toroidal plasma for symmetric and non-symmetric geometries.

  16. Influence of somatic cell count on mineral content and salt equilibria of milk

    Directory of Open Access Journals (Sweden)

    Primo Mariani


    Full Text Available Aim of this research was to study the effect of somatic cell count on mineral content and salt equilibria at the level of quarter milk samples. Ten Italian Friesian cows, in which two homologous quarters (front quarters in 1 cow, rear quarters in 6 cows and both rear and front quarters in 3 cows were characterised by a milk SCC400,000 cells/mL (HC-milk, respectively, were selected. Cows were milked at quarter level during the morning milking and a single sample was collected from each selected quarter, thus, 26 quarter milk samples were collected. Compared to LC-milk, HC-milk was characterised by a lower content of phosphorus and potassium and by a higher content of both sodium and chloride. The equilibrium of calcium, phosphorus and magnesium between the colloidal and soluble phase of milk and the mineralisation degree of the casein micelles, were not different between HC and LC milk.

  17. Using simple donors to drive the equilibria of glycosyltransferase-catalyzed reactions. (United States)

    Gantt, Richard W; Peltier-Pain, Pauline; Cournoyer, William J; Thorson, Jon S


    We report that simple glycoside donors can drastically shift the equilibria of glycosyltransferase-catalyzed reactions, transforming NDP-sugar formation from an endothermic to an exothermic process. To demonstrate the utility of this thermodynamic adaptability, we highlight the glycosyltransferase-catalyzed synthesis of 22 sugar nucleotides from simple aromatic sugar donors, as well as the corresponding in situ formation of sugar nucleotides as a driving force in the context of glycosyltransferase-catalyzed reactions for small-molecule glycodiversification. These simple aromatic donors also enabled a general colorimetric assay for glycosyltransfer, applicable to drug discovery, protein engineering and other fundamental sugar nucleotide-dependent investigations. This study directly challenges the general notion that NDP-sugars are 'high-energy' sugar donors when taken out of their traditional biological context.

  18. From one-dimensional fields to Vlasov equilibria: Theory and application of Hermite polynomials

    CERN Document Server

    Allanson, O; Troscheit, S; Wilson, F


    We consider the theory and application of a solution method for the inverse problem in collisionless equilibria, namely that of calculating a Vlasov-Maxwell equilibrium for a given macroscopic (fluid) equilibrium. Using Jeans' Theorem, the equilibrium distribution functions are expressed as functions of the constants of motion, in the form of a Maxwellian multiplied by an unknown function of the canonical momenta. In this case it is possible to reduce the inverse problem to inverting Weierstrass transforms, which we achieve by using expansions over Hermite polynomials. A sufficient condition on the pressure tensor is found which guarantees the convergence and the boundedness of the candidate solution, when satisfied. This condition is obtained by elementary means, and it is clear how to put it into practice. We also argue that for a given pressure tensor for which our method applies, there always exists a positive distribution function solution for a sufficiently magnetised plasma. Illustrative examples of th...

  19. Experimental confirmation of stable, small-debye-length, pure-electron-plasma equilibria in a stellarator. (United States)

    Kremer, J P; Pedersen, T Sunn; Lefrancois, R G; Marksteiner, Q


    The creation of the first small-Debye length, low temperature pure electron plasmas in a stellarator is reported. A confinement time of 20 ms has been measured. The long confinement time implies the existence of macroscopically stable equilibria and that the single particle orbits are well confined despite the lack of quasisymmetry in the device, the Columbia non-neutral torus. This confirms the beneficial confinement effects of strong electric fields and the resulting rapid E x B rotation of the electrons. The particle confinement time is presently limited by the presence of bulk insulating materials in the plasma, rather than any intrinsic plasma transport processes. A nearly flat temperature profile is seen in the inner part of the plasma.

  20. Phase equilibria of binary and ternary n-alkane solutions in supercritical ethylene, 1-butene, and ethylene + 1-butene: Transition from type A through LCST to U-LCST behavior predicted and confirmed experimentally

    Energy Technology Data Exchange (ETDEWEB)

    Gregg, C.J.; Stein, F.P. (Lehigh Univ., Bethlehem, PA (United States). Dept. of Chemical Engineering); Chen, Shenjer; Radosz, M. (Exxon Research and Engineering Co., Annandale, NJ (United States))


    Binary phase equilibria of C[sub 20] +, C[sub 30] +, and C[sub 40] + ethylene are correlated with three equations of state, the Redlich-Kwong-Soave (Soave), the generalized van der Waals-Prigogine (vdW-P), and the statistical associating fluid theory (SAFT), with special emphasis on the mixture critical region. The SAFT correlation is found to be the most reliable. SAFT predictive powers are tested on C[sub 26] + ethylene and a new set of experimental data taken in this work for C[sub 36] + 1-butene and C[sub 36] + ethylene + 1-butene. The SAFT predictions are found to be in good agreement with the experimental data. Equally important, the SAFT predictions allow for understanding the continuous transition of phase behavior, from type A (C[sub 36] + 1-butene) through LCST (C[sub 36] + ethylene + 1-butene) to U-LCST (C[sub 36] + ethylene).

  1. Investigations of (acid+base) equilibria in systems modelling interactions occurring in biomolecules

    Energy Technology Data Exchange (ETDEWEB)

    Kozak, Anna [Department of General Chemistry, University of Gdansk, Sobieskiego 18, 80-952 Gdansk (Poland); Czaja, Malgorzata [Department of General Chemistry, University of Gdansk, Sobieskiego 18, 80-952 Gdansk (Poland); Chmurzynski, Lech [Department of General Chemistry, University of Gdansk, Sobieskiego 18, 80-952 Gdansk (Poland)]. E-mail:


    By using the potentiometric microtitration method, acidity constants, K{sub a}, anionic, K{sub AHA{sup -}}, and cationic, K{sub BHB{sup +}}, homoconjugation constants, as well as molecular heteroconjugation, K{sub BHA}, constants have been determined in (acid+base) systems formed by the following compounds: acetic acid, phenol, n-butylamine, imidazole, and 4(5)-methylimidazole. These compounds constitute fragments of the side chains of amino acids capable of proton exchange in active sites of enzymes. The (acid+base) equilibria were studied in five polar solvents of different properties, namely in aprotic protophobic acetonitrile, acetone and propylene carbonate, in aprotic protophilic dimethyl sulfoxide and in amphiprotic methanol. The lowest values of the acidity constants of the molecular and cationic acids have been found in aprotic protophobic polar solvents - acetonitrile, propylene carbonate and acetone. Their acid strength have been found to depend on solvent basicity expressed as donor numbers, DN. These media, in particular acetonitrile and acetone, are also favourable for establishing molecular homo- and heteroconjugation equilibria. The most stable homocomplexes are formed in the case of acetic acid (K{sub AHA{sup -}} values range from 2.26 to 3.56 in these media, being more than an order of magnitude higher than those for the remaining compounds). The magnitudes of lgK{sub BHA} reveal that the most stable heterocomplexes are formed by n-butylamine and acetic acid that are characterized by the smallest differences in pK{sub a} values.

  2. Equilibria model for pH variations and ion adsorption in capacitive deionization electrodes. (United States)

    Hemmatifar, Ali; Oyarzun, Diego I; Palko, James W; Hawks, Steven A; Stadermann, Michael; Santiago, Juan G


    Ion adsorption and equilibrium between electrolyte and microstructure of porous electrodes are at the heart of capacitive deionization (CDI) research. Surface functional groups are among the factors which fundamentally affect adsorption characteristics of the material and hence CDI system performance in general. Current CDI-based models for surface charge are mainly based on a fixed (constant) charge density, and do not treat acid-base equilibria of electrode microstructure including so-called micropores. We here expand current models by coupling the modified Donnan (mD) model with weak electrolyte acid-base equilibria theory. In our model, surface charge density can vary based on equilibrium constants (pK's) of individual surface groups as well as micropore and electrolyte pH environments. In this initial paper, we consider this equilibrium in the absence of Faradaic reactions. The model shows the preferential adsorption of cations versus anions to surfaces with respectively acidic or basic surface functional groups. We introduce a new parameter we term "chemical charge efficiency" to quantify efficiency of salt removal due to surface functional groups. We validate our model using well controlled titration experiments for an activated carbon cloth (ACC), and quantify initial and final pH of solution after adding the ACC sample. We also leverage inductively coupled plasma mass spectrometry (ICP-MS) and ion chromatography (IC) to quantify the final background concentrations of individual ionic species. Our results show a very good agreement between experiments and model. The model is extendable to a wide variety of porous electrode systems and CDI systems with applied potential. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. State conditions transferability of vapor-liquid equilibria via fluctuation solution theory with correlation function integrals from molecular dynamics simulations

    DEFF Research Database (Denmark)

    Christensen, Steen; Peters, Günther H.J.; Hansen, Flemming Yssing


    The ‘State Conditions Transferability’ category of IFPSC 2006 tests prediction of binary vapor–liquid isotherms for mixtures of ethanol and the refrigerant HFF-227ea (1,1,1,2,3,3,3-heptafluoropropane). We predict these isotherms using fluctuation solution theory (FST). The method is based......–457] comprise the nearly ideal benzene/methyl acetate system, and the less ideal benzene/ethanol system at ambient temperatures. Both are at low pressures and remote from the pure component critical points. For the IFPSC system, we have used the same method even though predictions are for conditions remote from...

  4. Doppler sonographic evaluation of venogenic extremity swellings ...

    African Journals Online (AJOL)

    Doppler ultrasound is very useful in the evaluation of extremity DVT. All clinically suspected cases should be evaluated with this modality due to limited sensitivity of clinical evaluation in the diagnosis of DVT. Further correlative studies in comparison to venography and hematologic indices are also recommended.

  5. Extreme Programming: Maestro Style (United States)

    Norris, Jeffrey; Fox, Jason; Rabe, Kenneth; Shu, I-Hsiang; Powell, Mark


    "Extreme Programming: Maestro Style" is the name of a computer programming methodology that has evolved as a custom version of a methodology, called extreme programming that has been practiced in the software industry since the late 1990s. The name of this version reflects its origin in the work of the Maestro team at NASA's Jet Propulsion Laboratory that develops software for Mars exploration missions. Extreme programming is oriented toward agile development of software resting on values of simplicity, communication, testing, and aggressiveness. Extreme programming involves use of methods of rapidly building and disseminating institutional knowledge among members of a computer-programming team to give all the members a shared view that matches the view of the customers for whom the software system is to be developed. Extreme programming includes frequent planning by programmers in collaboration with customers, continually examining and rewriting code in striving for the simplest workable software designs, a system metaphor (basically, an abstraction of the system that provides easy-to-remember software-naming conventions and insight into the architecture of the system), programmers working in pairs, adherence to a set of coding standards, collaboration of customers and programmers, frequent verbal communication, frequent releases of software in small increments of development, repeated testing of the developmental software by both programmers and customers, and continuous interaction between the team and the customers. The environment in which the Maestro team works requires the team to quickly adapt to changing needs of its customers. In addition, the team cannot afford to accept unnecessary development risk. Extreme programming enables the Maestro team to remain agile and provide high-quality software and service to its customers. However, several factors in the Maestro environment have made it necessary to modify some of the conventional extreme

  6. Electronics for Extreme Environments (United States)

    Patel, J. U.; Cressler, J.; Li, Y.; Niu, G.


    Most of the NASA missions involve extreme environments comprising radiation and low or high temperatures. Current practice of providing friendly ambient operating environment to electronics costs considerable power and mass (for shielding). Immediate missions such as the Europa orbiter and lander and Mars landers require the electronics to perform reliably in extreme conditions during the most critical part of the mission. Some other missions planned in the future also involve substantial surface activity in terms of measurements, sample collection, penetration through ice and crust and the analysis of samples. Thus it is extremely critical to develop electronics that could reliably operate under extreme space environments. Silicon On Insulator (SOI) technology is an extremely attractive candidate for NASA's future low power and high speed electronic systems because it offers increased transconductance, decreased sub-threshold slope, reduced short channel effects, elimination of kink effect, enhanced low field mobility, and immunity from radiation induced latch-up. A common belief that semiconductor devices function better at low temperatures is generally true for bulk devices but it does not hold true for deep sub-micron SOI CMOS devices with microscopic device features of 0.25 micrometers and smaller. Various temperature sensitive device parameters and device characteristics have recently been reported in the literature. Behavior of state of the art technology devices under such conditions needs to be evaluated in order to determine possible modifications in the device design for better performance and survivability under extreme environments. Here, we present a unique approach of developing electronics for extreme environments to benefit future NASA missions as described above. This will also benefit other long transit/life time missions such as the solar sail and planetary outposts in which electronics is out open in the unshielded space at the ambient space

  7. Computation of liquid-liquid equilibria and phase stabilities: implications for RH-dependent gas/particle partitioning of organic-inorganic aerosols

    National Research Council Canada - National Science Library

    A. Zuend; C. Marcolli; T. Peter; J. H. Seinfeld


    .... Such liquid-liquid equilibria (LLE) affect the gas/particle partitioning of the different semivolatile compounds and might significantly alter both particle mass and composition as compared to a one-phase particle...

  8. Voltammetric investigation of the complexation equilibria in the presence of a low level of supporting electrolyte Part 1: Steady-state current-potential curves for inert complexes

    NARCIS (Netherlands)

    Palys, M.J.; Palys, Marcin J.; Stojek, Zbigniew; Bos, M.; van der Linden, W.E.


    The use of microelectrodes for voltammetric investigations of the complexation equilibria at very low concentrations of supporting electrolyte allows the risk of competitive complexation or contamination to be avoided, makes the activities of the species involved closer to their concentrations

  9. Extremely deformable structures

    CERN Document Server


    Recently, a new research stimulus has derived from the observation that soft structures, such as biological systems, but also rubber and gel, may work in a post critical regime, where elastic elements are subject to extreme deformations, though still exhibiting excellent mechanical performances. This is the realm of ‘extreme mechanics’, to which this book is addressed. The possibility of exploiting highly deformable structures opens new and unexpected technological possibilities. In particular, the challenge is the design of deformable and bi-stable mechanisms which can reach superior mechanical performances and can have a strong impact on several high-tech applications, including stretchable electronics, nanotube serpentines, deployable structures for aerospace engineering, cable deployment in the ocean, but also sensors and flexible actuators and vibration absorbers. Readers are introduced to a variety of interrelated topics involving the mechanics of extremely deformable structures, with emphasis on ...

  10. Statistics of Extremes

    KAUST Repository

    Davison, Anthony C.


    Statistics of extremes concerns inference for rare events. Often the events have never yet been observed, and their probabilities must therefore be estimated by extrapolation of tail models fitted to available data. Because data concerning the event of interest may be very limited, efficient methods of inference play an important role. This article reviews this domain, emphasizing current research topics. We first sketch the classical theory of extremes for maxima and threshold exceedances of stationary series. We then review multivariate theory, distinguishing asymptotic independence and dependence models, followed by a description of models for spatial and spatiotemporal extreme events. Finally, we discuss inference and describe two applications. Animations illustrate some of the main ideas. © 2015 by Annual Reviews. All rights reserved.

  11. Phase equilibria of H{sub 2}SO{sub 4}, HNO{sub 3}, and HCl hydrates and the composition of polar stratospheric clouds

    Energy Technology Data Exchange (ETDEWEB)

    Wooldridge, P.J.; Zhang, R.; Molina, M.J. [Massachusetts Institute of Technology, Cambridge, MA (United States)] [and others


    Thermodynamic properties and phase equilibria behavior for the hydrates and coexisting pairs of hydrates of common acids which exist in the stratosphere are assembled from new laboratory measurements and standard literature data. The analysis focuses upon solid-solid-vapor equilibria at temperatures around 200 K and includes new calorimetric and vapor pressure data. Calculated partial pressures versus 1/T slopes for the hydrates and coexisting hydrates agree well with experimental data where available. 42 refs., 5 figs., 4 tabs.

  12. Adventure and Extreme Sports. (United States)

    Gomez, Andrew Thomas; Rao, Ashwin


    Adventure and extreme sports often involve unpredictable and inhospitable environments, high velocities, and stunts. These activities vary widely and include sports like BASE jumping, snowboarding, kayaking, and surfing. Increasing interest and participation in adventure and extreme sports warrants understanding by clinicians to facilitate prevention, identification, and treatment of injuries unique to each sport. This article covers alpine skiing and snowboarding, skateboarding, surfing, bungee jumping, BASE jumping, and whitewater sports with emphasis on epidemiology, demographics, general injury mechanisms, specific injuries, chronic injuries, fatality data, and prevention. Overall, most injuries are related to overuse, trauma, and environmental or microbial exposure. Copyright © 2016 Elsevier Inc. All rights reserved.

  13. Extremal graph theory

    CERN Document Server

    Bollobas, Bela


    The ever-expanding field of extremal graph theory encompasses a diverse array of problem-solving methods, including applications to economics, computer science, and optimization theory. This volume, based on a series of lectures delivered to graduate students at the University of Cambridge, presents a concise yet comprehensive treatment of extremal graph theory.Unlike most graph theory treatises, this text features complete proofs for almost all of its results. Further insights into theory are provided by the numerous exercises of varying degrees of difficulty that accompany each chapter. A

  14. Redox equilibria of iron oxides in aqueous-based magnetite dispersions: effect of pH and redox potential. (United States)

    Pang, Suh Cem; Chin, Suk Fun; Anderson, Marc A


    The effect of pH and redox potential on the redox equilibria of iron oxides in aqueous-based magnetite dispersions was investigated. The ionic activities of each dissolved iron species in equilibrium with magnetite nanoparticles were determined and contoured within the Eh-pH framework of a composite stability diagram. Both standard redox potentials and equilibrium constants for all major iron oxide redox equilibria in magnetite dispersions were found to differ from values reported for noncolloidal systems. The "triple point" position of redox equilibrium among Fe(II) ions, magnetite, and hematite shifted to a higher standard redox potential and an equilibrium constant which was several orders of magnitude higher. The predominant area of magnetite stability was enlarged to cover a wider range of both pH and redox potentials as compared to that of a noncolloidal magnetite system.

  15. Modification of Sako-Wu-Prausnitz equation of state for fluid phase equilibria in polyethylene-ethylene systems at high pressures

    Directory of Open Access Journals (Sweden)

    F. Gharagheizi


    Full Text Available In order to model phase equilibria at all pressures, it is necessary to have an equation of state. We have chosen the Sako-Wu-Prausnitz cubic equation of state, which had shown some promising results. However, in order to satisfy our demands, we had to modify it slightly and fit new pure component parameters. New pure component parameters have been determined for ethylene and the n-alkane series, using vapor pressure data, saturated liquid volume and one-phase PVT-data. For higher n-alkanes, where vapor pressure data are poor or not available, determination of the pure component parameters was made in part by extrapolation and in part by fitting to one-phase PVT-data. Using one-fluid van der Waals mixing rules, with one adjustable interaction parameter, good correlation of binary hydrocarbon system was obtained, except for the critical region. The extension of the equation of state to polyethylene systems is covered in this work. Using the determined parameters, flash and cloud point calculations were performed, and treating the polymer as polydisperse. The results fit data well.

  16. A potentiometric study of (acid+base) equilibria in substituted 4-nitropyridine N-oxide systems in methanol and dimethyl sulfoxide

    Energy Technology Data Exchange (ETDEWEB)

    Gurzynski, Lukasz [Department of General Chemistry, University of Gdansk, Sobieskiego 18, 80-952 Gdansk (Poland); Puszko, Aniela [Department of Organic Chemistry, School of Economics, Wroclaw (Poland); Makowski, Mariusz [Department of General Chemistry, University of Gdansk, Sobieskiego 18, 80-952 Gdansk (Poland); Chmurzynski, Lech [Department of General Chemistry, University of Gdansk, Sobieskiego 18, 80-952 Gdansk (Poland)]. E-mail:


    The acid dissociation constants for cationic acids conjugated with 4-nitropyridine N-oxides have been determined using potentiometric titration method. The measurements in the systems of thirteen 4-nitropyridine N-oxide derivatives were carried out in the polar amphiprotic methanol (MeOH) and in the aprotic protophilic dimethyl sulfoxide (DMSO). Likewise as in the polar aprotic protophobic solvents (acetonitrile, acetone) it was found that in MeOH for all N-oxides studied the pK{sub a} values were readily determinable, whereas in DMSO the pK{sub a} values were hardly determinable or indeterminable by using the potentiometric method. In addition, just like in our previous investigations it was revealed that the sequence of the pK{sub a} values of the cationic acids in methanol is the same as in the water and the values are lower than those determined in acetonitrile and acetone. Also, it was found that the phenomenon of cationic homoconjugation equilibria was not present in the systems involving 4-nitropyridine N-oxide derivatives in both solvents used. Furthermore, protonation energies, {delta}E{sub prot}, and Gibbs free enthalpies, {delta}G{sub prot}, in vacuo have been compared with acid dissociation constants (expressed as pK{sub a}{sup MeOH} values) of the protonated N-oxides determined by potentiometric titration in methanol to establish a correlation between these magnitudes.

  17. Ab initio Investigations of the Equilibria between Trichlorothioacetyl Chloride, Tetrachlorothiirane, and Trichloroethenesulfenyl Chloride, their Reactants and Decomposition Products

    DEFF Research Database (Denmark)

    Pedersen, Kim Vestergaard; Christensen, Henrik; Shim, Irene


    Trichlorothioacetyl chloride 1, tetrachlorothiirane 2, and trichloroethenesulfenyl chloride 3 and the equilibria between them have been investigated by ab initio Hartree-Fock (HF), Møller-Plesset second order perturbation (MP2) calculations, and by Gaussian-3 theory, G3(MP2). The transition states...... of the isomerization reactions have been identified. Also investigated were possible reactions leading to the isomers and their possible decomposition products. The results show that the unobserved isomerization reactions are feasible....

  18. Solid–liquid equilibria for binary and ternary systems with the Cubic-Plus-Association (CPA) equation of state

    DEFF Research Database (Denmark)

    Fettouhi, André; Thomsen, Kaj


    A systematic investigation of the CPA model's performance within solid-liquid equilibria (SLE) in binary mixtures (methane + ethane, methane + heptane, methane + benzene, methane + CO2, ethane + heptane, ethane + CO2, 1-propanol + 1,4-dioxane, ethanol + water, 2-propanol + water) is presented. Th....... The results from the binary mixtures are used to predict SLE behaviour in ternary mixtures (methane + ethane + heptane, methane + ethane + CO2). Our results are compared with experimental data found in the literature....

  19. Isobaric (vapor + liquid) equilibria of 1-ethyl-3-methylimidazolium ethylsulfate plus (propionaldehyde or valeraldehyde): Experimental data and prediction

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez, Victor H. [School of Chemical Engineering, University of Campinas (UNICAMP), Av. Albert Einstein 500, 13083-852 Campinas, SP (Brazil); Mattedi, Silvana [Chemical Engineering Department, Polytechnic School, Federal University of Bahia (UFBA), R. Aristides Novis 2, 40210-630 Salvador, BA (Brazil); Aznar, Martin, E-mail: maznar@feq.unicamp.b [School of Chemical Engineering, University of Campinas (UNICAMP), Av. Albert Einstein 500, 13083-852 Campinas, SP (Brazil)


    Research highlights: We report density, refraction index, and VLE for (propionaldehyde or valeraldehyde) + [emim][EtSO{sub 4}]. The Peng-Robinson + Wong-Sandler + COSMO-SAC model was used to predict density and VLE. The densities were predicted with deviations below than 2.3%. The experimental VLE was predicted with deviations below than 1.6%. - Abstract: This paper reports the density, refraction index, and (vapor + liquid) equilibria (VLE) for binary systems {l_brace}aldehyde + 1-ethyl-3-methylimidazolium ethylsulfate ([emim][EtSO{sub 4}]){r_brace}: {l_brace}propionaldehyde + [emim][EtSO{sub 4}]{r_brace} and {l_brace}valeraldehyde + [emim][EtSO{sub 4}]{r_brace}. The uncertainties for the temperature, pressure, and compositions measurements for the phase equilibria are {+-}0.1 K, {+-}0.01 kPa and {+-}0.0004, respectively. A qualitative analysis of the variation of the properties with changes in solvent and temperature was performed. The Peng-Robinson equation of state (PR EoS), coupled with the Wong-Sandler mixing rule (WS), is used to describe the experimental data. To calculate activity coefficients we used three different models: NRTL, UNIQUAC, and COSMO-SAC. Since the predictive liquid activity coefficient model COSMO-SAC is used in the Wong-Sandler mixing rule, the resulting thermodynamic model is a completely predictive one. The prediction results for the density and for the (vapor + liquid) equilibria have a deviation lower than 2.3% and 1.6%, respectively. The (vapor + liquid) equilibria predictions show a good description for the propionaldehyde system and only a qualitative description for the valeraldehyde system.

  20. Thermodynamic characteristics of acid-base equilibria of DL-α-alanyl-DL-norleucine in aqueous solutions at 298 K (United States)

    Lytkin, A. I.; Chernikov, V. V.; Krutova, O. N.; Bychkova, S. A.; Skvortsov, I. A.


    Protolytic equilibria in aqueous solutions of DL-α-alanyl-DL-norleucine are studied via potentiometry and calorimetry. Measurements are made at 298.15 K and ionic strengths of 0.5, 1.0, and 1.5 (against a background of potassium nitrate). The thermodynamic characteristics (p K, Δ G, Δ H, Δ S) of the stepwise dissociation of the dipeptide both in aqueous-salt solutions and in standard solution are obtained for the first time.

  1. Acute lower extremity ischaemia

    African Journals Online (AJOL)

    In a nutshell. • A patient with sudden onset of a cold, weak, numb and painful foot has acute lower extremity ischaemia (ALEXI) until proven otherwise. Labelling patients as acute gout, acute phlegmasia (deep vein thrombosis), acute sciatica, etc. may result in unnecessary delays in treatment, with tragic consequences.

  2. Injuries in extreme sports. (United States)

    Laver, Lior; Pengas, Ioannis P; Mei-Dan, Omer


    Extreme sports (ES) are usually pursued in remote locations with little or no access to medical care with the athlete competing against oneself or the forces of nature. They involve high speed, height, real or perceived danger, a high level of physical exertion, spectacular stunts, and heightened risk element or death.Popularity for such sports has increased exponentially over the past two decades with dedicated TV channels, Internet sites, high-rating competitions, and high-profile sponsors drawing more participants.Recent data suggest that the risk and severity of injury in some ES is unexpectedly high. Medical personnel treating the ES athlete need to be aware there are numerous differences which must be appreciated between the common traditional sports and this newly developing area. These relate to the temperament of the athletes themselves, the particular epidemiology of injury, the initial management following injury, treatment decisions, and rehabilitation.The management of the injured extreme sports athlete is a challenge to surgeons and sports physicians. Appropriate safety gear is essential for protection from severe or fatal injuries as the margins for error in these sports are small.The purpose of this review is to provide an epidemiologic overview of common injuries affecting the extreme athletes through a focus on a few of the most popular and exciting extreme sports.

  3. Deficiently extremal Gorenstein algebras

    Indian Academy of Sciences (India)

    For the given codimension g ≥ 3 and initial degree p ≥ 2, a Gorenstein algebra R/I with minimal multiplicity is extremal in the sense of Schenzel [8]. This has a nice structural implication: the minimal resolution of R/I must be pure and almost linear, and so their. Betti numbers are given by Herzog and Kühl [3] formulae.

  4. Hydrological extremes and security

    Directory of Open Access Journals (Sweden)

    Z. W. Kundzewicz


    Full Text Available Economic losses caused by hydrological extremes – floods and droughts – have been on the rise. Hydrological extremes jeopardize human security and impact on societal livelihood and welfare. Security can be generally understood as freedom from threat and the ability of societies to maintain their independent identity and their functional integrity against forces of change. Several dimensions of security are reviewed in the context of hydrological extremes. The traditional interpretation of security, focused on the state military capabilities, has been replaced by a wider understanding, including economic, societal and environmental aspects that get increasing attention. Floods and droughts pose a burden and serious challenges to the state that is responsible for sustaining economic development, and societal and environmental security. The latter can be regarded as the maintenance of ecosystem services, on which a society depends. An important part of it is water security, which can be defined as the availability of an adequate quantity and quality of water for health, livelihoods, ecosystems and production, coupled with an acceptable level of water-related risks to people, environments and economies. Security concerns arise because, over large areas, hydrological extremes − floods and droughts − are becoming more frequent and more severe. In terms of dealing with water-related risks, climate change can increase uncertainties, which makes the state’s task to deliver security more difficult and more expensive. However, changes in population size and development, and level of protection, drive exposure to hydrological hazards.

  5. Extremism and Disability Chic (United States)

    Kauffman, James M.; Badar, Jeanmarie


    The word chic refers to something fashionable or stylish. Chic varies for individuals and groups and with time and place. Something chic may have desirable or undesirable long-term consequences. Disability and extremism are also changeable concepts, depending on comparison to social norms. People with disabilities should have the option of being…

  6. Extreme heat and runoff extremes in the Swiss Alps

    Directory of Open Access Journals (Sweden)

    M. Zappa


    Full Text Available The hydrological response of Swiss river basins to the 2003 European summer heatwave was evaluated by a combined analysis of historical discharge records and specific applications of distributed hydrological modeling. In the summer of 2003, the discharge from headwater streams of the Swiss Central Plateau was only 40%–60% of the long-term average. For alpine basins runoff was about 60%–80% of the average. Glacierized basins showed the opposite behavior. According to the degree of glacierization, the average summer runoff was close or even above average. The hydrological model PREVAH was applied for the period 1982–2005. Even if the model was not calibrated for such extreme meteorological conditions, it was well able to simulate the hydrological responses of three basins. The aridity index φ describes feedbacks between hydrological and meteorological anomalies, and was adopted as an indicator of hydrological drought. The anomalies of φ and temperature in the summer of 2003 exceeded the 1982–2005 mean by more than 2 standard deviations. Catchments without glaciers showed negative correlations between φ and discharge R. In basins with about 15% glacierization, φ and R were not correlated. River basins with higher glacier percentages showed a positive correlation between φ and R. Icemelt was positively correlated with φ and reduced the variability of discharge with larger amounts of meltwater. Runoff generation from the non-glaciated sub-areas was limited by high evapotranspiration and reduced precipitation. The 2003 summer heatwave could be a precursor to similar events in the near future. Hydrological models and further data analysis will allow the identification of the most sensitive regions where heatwaves may become a recurrent natural hazard with large environmental, social and economical impacts.

  7. Modeling complex equilibria in isothermal titration calorimetry experiments: thermodynamic parameters estimation for a three-binding-site model. (United States)

    Le, Vu H; Buscaglia, Robert; Chaires, Jonathan B; Lewis, Edwin A


    Isothermal titration calorimetry (ITC) is a powerful technique that can be used to estimate a complete set of thermodynamic parameters (e.g., K(eq) (or ΔG), ΔH, ΔS, and n) for a ligand-binding interaction described by a thermodynamic model. Thermodynamic models are constructed by combining equilibrium constant, mass balance, and charge balance equations for the system under study. Commercial ITC instruments are supplied with software that includes a number of simple interaction models, for example, one binding site, two binding sites, sequential sites, and n-independent binding sites. More complex models, for example, three or more binding sites, one site with multiple binding mechanisms, linked equilibria, or equilibria involving macromolecular conformational selection through ligand binding, need to be developed on a case-by-case basis by the ITC user. In this paper we provide an algorithm (and a link to our MATLAB program) for the nonlinear regression analysis of a multiple-binding-site model with up to four overlapping binding equilibria. Error analysis demonstrates that fitting ITC data for multiple parameters (e.g., up to nine parameters in the three-binding-site model) yields thermodynamic parameters with acceptable accuracy. Copyright © 2012 Elsevier Inc. All rights reserved.

  8. Phase equilibria in fullerene-containing systems as a basis for development of manufacture and application processes for nanocarbon materials (United States)

    Semenov, K. N.; Charykov, N. A.; Postnov, V. N.; Sharoyko, V. V.; Murin, I. V.


    This review is the first attempt to integrate the available data on all types of phase equilibria (solubility, extraction and sorption) in systems containing light fullerenes (C60 and C70). In the case of solubility diagrams, the following types of phase equilibria are considered: individual fullerene (C60 or C70)-solvent under polythermal and polybaric conditions; C60-C70-solvent, individual fullerene-solvent(1)-solvent(2), as well as multicomponent systems comprising a single fullerene or an industrial mixture of fullerenes and vegetable oils, animal fats or essential oils under polythermal conditions. All published experimental data on the extraction equilibria in C60-C70-liquid phase(1)-liquid phase(2) systems are described systematically and the sorption characteristics of various materials towards light fullerenes are estimated. The possibility of application of these experimental data for development of pre-chromatographic and chromatographic methods for separation of fullerene mixtures and application of fullerenes as nanomodifiers are described. The bibliography includes 87 references.

  9. On the manifestation of coexisting nontrivial equilibria leading to potential well escapes in an inhomogeneous floating body (United States)

    Sequeira, Dane; Wang, Xue-She; Mann, B. P.


    This paper examines the bifurcation and stability behavior of inhomogeneous floating bodies, specifically a rectangular prism with asymmetric mass distribution. A nonlinear model is developed to determine the stability of the upright and tilted equilibrium positions as a function of the vertical position of the center of mass within the prism. These equilibria positions are defined by an angle of rotation and a vertical position where rotational motion is restricted to a two dimensional plane. Numerical investigations are conducted using path-following continuation methods to determine equilibria solutions and evaluate stability. Bifurcation diagrams and basins of attraction that illustrate the stability of the equilibrium positions as a function of the vertical position of the center of mass within the prism are generated. These results reveal complex stability behavior with many coexisting solutions. Static experiments are conducted to validate equilibria orientations against numerical predictions with results showing good agreement. Dynamic experiments that examine potential well hopping behavior in a waveflume for various wave conditions are also conducted.

  10. Experimental investigation of phase equilibria in the Co-Ni-Zr ternary system

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xingjun; Yang, Shuiyuan; Yu, Wenjie; Wang, Cuiping [Xiamen Univ. (China). Fujian Key Laboratory of Materials Genome; Xiong, Huaping; Cheng, Yaoyong; Wu, Xin [Beijing Institute of Aeronautical Materials (China). Div. of Welding and Forging


    The phase equilibria of the Co-Ni-Zr ternary system at 1 000 C, 1 100 C and 1 200 C were experimentally investigated by means of back-scattered electron imaging, electron probe microanalysis and X-ray diffraction on the equilibrated ternary alloys. In this study, no ternary compound is found. The (αCo, Ni) phase region extends from the Ni-rich corner to the Co-rich corner with small solubility of Zr at three sections. At 1 000 C and 1 100 C, Ni{sub 5}Zr, Co{sub 2}Zr and Ni{sub 10}Zr{sub 7} phases have large solid solution ranges, but Ni{sub 10}Zr{sub 7} phase disappears at 1 200 C. The Ni{sub 7}Zr{sub 2}, NiZr, Co{sub 11}Zr{sub 2}, Co{sub 23}Zr{sub 6} and CoZr phases exhibit nearly linear compounds in the studied sections, and have large composition ranges. Additionally, some differences in phase relationship exist among the above three isothermal sections.

  11. Phase equilibria in the ternary In-Ni-Sn system at 700 °C. (United States)

    Schmetterer, C; Zemanova, A; Flandorfer, H; Kroupa, A; Ipser, H


    The phase equilibria of the ternary system In-Ni-Sn were investigated experimentally at 700 °C using X-ray diffraction (XRD) and scanning electron microscopy (SEM) including electron micro probe analysis (EMPA) and energy dispersive X-ray spectroscopy (EDX). A corresponding isothermal section was established based on these results. This particular temperature was chosen because it allowed obtaining reliable results within reasonable time. The existence of the ternary phase InNi 6 Sn 5 was confirmed whereas the ternary compound In 2 NiSn, reported earlier in literature, was found to be part of a large solid solution field based on binary InNi. The ternary solubility of the binary phases was established, and continuous solid solutions were found between the isostructural phases Ni 3 Sn LT and InNi 3 as well as between Ni 3 Sn 2 HT and InNi 2 . In addition, this isothermal section could be well reproduced by CALPHAD modelling. The resulting calculated isotherm at 700 °C is presented, too, and compared with the experimental results.

  12. Experimental determination of the phase equilibria in the Co–Cr–Ta ternary system

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, C.C. [Department of Materials Science and Engineering, College of Materials, Xiamen University, Xiamen 361005 (China); Yang, S.Y.; Liu, X.J. [Department of Materials Science and Engineering, College of Materials, Xiamen University, Xiamen 361005 (China); Research Center of Materials Design and Applications, Xiamen University, Xiamen 361005 (China); Wang, C.P., E-mail: [Department of Materials Science and Engineering, College of Materials, Xiamen University, Xiamen 361005 (China); Research Center of Materials Design and Applications, Xiamen University, Xiamen 361005 (China)


    Highlights: • Three isothermal sections at 800, 1000, and 1100 °C were established. • A large solubility of Cr is identified in the Co{sub 6}Ta{sub 7} phase. • The high–temperature phase (Co,Cr){sub 2}Ta(HT) was found to be stabilized at low temperatures. - Abstract: The phase equilibria in the Co–Cr–Ta ternary system were experimentally investigated by using backscattered electron (BSE), wavelength dispersive X-ray analyzer (WDX) and X-ray diffraction (XRD). Three isothermal sections of the Co–Cr–Ta ternary system at 800 °C, 900 °C and 1100 °C were experimentally determined. The experimental results show that: (1) No ternary compound is found in this system; (2) A large solubility of Cr is identified in the Co{sub 6}Ta{sub 7} phase; (3) The (Co, Cr){sub 2}Ta(HT) phase is stabilized at temperatures below it stability limits in Co–Ta and Cr–Ta binary systems in the range of Cr concentrations from 4 to 61 at.% and from 24 to 41 at.% Ta.

  13. Experimental investigation and thermodynamic assessment of phase equilibria in the Nb–Si–Zr ternary system

    Energy Technology Data Exchange (ETDEWEB)

    Li, J.; Guo, Y.H. [Department of Materials Science and Engineering, College of Materials, Xiamen University, Xiamen 361005 (China); Yang, S.Y.; Shi, Z.; Wang, C.P. [Department of Materials Science and Engineering, College of Materials, Xiamen University, Xiamen 361005 (China); Research Center of Materials Design and Applications, Xiamen University, Xiamen 361005 (China); Liu, X.J., E-mail: [Department of Materials Science and Engineering, College of Materials, Xiamen University, Xiamen 361005 (China); Research Center of Materials Design and Applications, Xiamen University, Xiamen 361005 (China)


    Highlights: • The sections of Nb–Si–Zr system at 1373, 1473 and 1573 K were determined. • Large solubilities of Nb in αZr{sub 5}Si{sub 4}, Zr{sub 3}Si{sub 2} and Zr{sub 2}Si phases were observed. • The thermodynamic assessment of Nb–Si–Zr ternary system was carried out. - Abstract: In this study, the phase equilibria of Nb–Si–Zr at 1373 K, 1473 K and 1573 K were experimentally determined by means of back-scattered electron (BSE), electron probe microanalysis (EPMA) and X-ray diffraction (XRD). The results show that there were five three-phase regions and sixteen two-phase regions in the studied isothermal sections, and no any ternary compounds were found. The solubility of Si in the Nb–Zr side is very small. Large solubilities of Nb in αZr{sub 5}Si{sub 4}, Zr{sub 3}Si{sub 2} and Zr{sub 2}Si phases were observed, otherwise the solubilities of Nb in ZrSi{sub 2}, αZrSi and Zr{sub 3}Si phases are relatively small. Based on the present experimental results, the thermodynamic assessment of Nb–Si–Zr system was carried out using the CALPHAD (Calculation of Phase Diagrams) method. The current calculated phase diagrams are in reasonable agreement with the present experimental data.

  14. Vapor Liquid Equilibria of Hydrofluorocarbons Using Dispersion-Corrected and Nonlocal Density Functionals. (United States)

    Goel, Himanshu; Butler, Charles L; Windom, Zachary W; Rai, Neeraj


    Recent developments in dispersion corrected and nonlocal density functionals are aimed at accurately capturing dispersion interactions, a key shortcoming of local and semilocal approximations of density functional theory. These functionals have shown significant promise for dimers and small clusters of molecules as well as crystalline materials. However, their efficacy for predicting vapor liquid equilibria is largely unexplored. In this work, we examine the accuracy of dispersion-corrected and nonlocal van der Waals functionals by computing the vapor liquid coexistence curves (VLCCs) of hydrofluoromethanes. Our results indicate that the PBE-D3 functional performs significantly better in predicting saturated liquid densities than the rVV10 functional. With the PBE-D3 functional, we also find that as the number of fluorine atoms increase in the molecule, the accuracy of saturated liquid density prediction improves as well. All the functionals significantly underpredict the saturated vapor densities, which also result in an underprediction of saturated vapor pressure of all compounds. Despite the differences in the bulk liquid densities, the local microstructures of the liquid CFH3 and CF2H2 are relatively insensitive to the density functional employed. For CF3H, however, rVV10 predicts slightly more structured liquid than the PBE-D3 functional.

  15. Topology-dependent rationality and quantal response equilibria in structured populations (United States)

    Roman, Sabin; Brede, Markus


    Given that the assumption of perfect rationality is rarely met in the real world, we explore a graded notion of rationality in socioecological systems of networked actors. We parametrize an actors' rationality via their place in a social network and quantify system rationality via the average Jensen-Shannon divergence between the games Nash and logit quantal response equilibria. Previous work has argued that scale-free topologies maximize a system's overall rationality in this setup. Here we show that while, for certain games, it is true that increasing degree heterogeneity of complex networks enhances rationality, rationality-optimal configurations are not scale-free. For the Prisoner's Dilemma and Stag Hunt games, we provide analytic arguments complemented by numerical optimization experiments to demonstrate that core-periphery networks composed of a few dominant hub nodes surrounded by a periphery of very low degree nodes give strikingly smaller overall deviations from rationality than scale-free networks. Similarly, for the Battle of the Sexes and the Matching Pennies games, we find that the optimal network structure is also a core-periphery graph but with a smaller difference in the average degrees of the core and the periphery. These results provide insight on the interplay between the topological structure of socioecological systems and their collective cognitive behavior, with potential applications to understanding wealth inequality and the structural features of the network of global corporate control.

  16. Thermodynamics of mixtures containing alkoxyethanols. XXVIII: Liquid-liquid equilibria for 2-phenoxyethanol + selected alkanes

    Energy Technology Data Exchange (ETDEWEB)

    Alonso, Victor; Garcia, Mario [G.E.T.E.F., Grupo Especializado en Termodinamica de Equilibrio entre Fases, Departamento de Fisica Aplicada, Facultad de Ciencias, Universidad de Valladolid, E-47071 Valladolid (Spain); Gonzalez, Juan Antonio, E-mail: [G.E.T.E.F., Grupo Especializado en Termodinamica de Equilibrio entre Fases, Departamento de Fisica Aplicada, Facultad de Ciencias, Universidad de Valladolid, E-47071 Valladolid (Spain); Garcia De La Fuente, Isaias; Cobos, Jose Carlos [G.E.T.E.F., Grupo Especializado en Termodinamica de Equilibrio entre Fases, Departamento de Fisica Aplicada, Facultad de Ciencias, Universidad de Valladolid, E-47071 Valladolid (Spain)


    Highlights: {yields} LLE coexistence curves were determined for mixtures of 2PhEE with alkanes. {yields} UCST values are higher for n-alkane systems than for solutions with cyclic alkanes. {yields} For the latter mixtures, UCST increases with the size of the alkyl group attached. {yields} Alkoxyethanol-alkoxyethanol interactions are enhanced by aromatic group in cellosolve. - Abstract: The coexistence curves of the liquid-liquid equilibria (LLE) for systems of 2-phenoxyethanol (2PhEE) with heptane, octane, cyclohexane, methylcyclohexane or ethylcyclohexane have been determined by the method of the critical opalescence using a laser scattering technique. All the curves show an upper critical solution temperature (UCST), have a rather horizontal top and their symmetry depends on the relative size of the mixture compounds. UCST values are higher for systems with linear alkanes than for solutions including cyclic alkanes. For these mixtures, the UCST increases with the size of the alkyl group attached to the cyclic part of the molecule. It is shown that interactions between alkoxyethanol molecules are stronger when the hydroxyether contains an aromatic group. Data are used to determine the critical exponent for the order parameter mole fraction. Values obtained are consistent with those provided by the Ising model or by the renormalization group theory.

  17. The Impact of Prophage on the Equilibria and Stability of Phage and Host (United States)

    Yu, Pei; Nadeem, Alina; Wahl, Lindi M.


    In this paper, we present a bacteriophage model that includes prophage, that is, phage genomes that are incorporated into the host cell genome. The general model is described by an 18-dimensional system of ordinary differential equations. This study focuses on asymptotic behaviour of the model, and thus the system is reduced to a simple six-dimensional model, involving uninfected host cells, infected host cells and phage. We use dynamical system theory to explore the dynamic behaviour of the model, studying in particular the impact of prophage on the equilibria and stability of phage and host. We employ bifurcation and stability theory, centre manifold and normal form theory to show that the system has multiple equilibrium solutions which undergo a series of bifurcations, finally leading to oscillating motions. Numerical simulations are presented to illustrate and confirm the analytical predictions. The results of this study indicate that in some parameter regimes, the host cell population may drive the phage to extinction through diversification, that is, if multiple types of host emerge; this prediction holds even if the phage population is likewise diverse. This parameter regime is restricted, however, if infecting phage are able to recombine with prophage sequences in the host cell genome.

  18. Role of backbone-solvent interactions in determining conformational equilibria of intrinsically disordered proteins. (United States)

    Tran, Hoang T; Mao, Albert; Pappu, Rohit V


    Intrinsically disordered proteins (IDPs) are functional proteins that do not fold into well-defined three-dimensional structures under physiological conditions. IDP sequences have low hydrophobicity, and hence, recent experiments have focused on quantitative studies of conformational ensembles of archetypal IDP sequences such as polyglutamine and glycine-serine block copolypeptides. Results from these experiments show that, despite the absence of hydrophobic residues, polar IDPs prefer ensembles of collapsed structures in aqueous milieus. Do these preferences originate in interactions that are unique to polar sidechains? The current study addresses this issue by analyzing conformational equilibria for polyglycine and a glycine-serine block copolypeptide in two environments, namely, water and 8 M urea. Polyglycine, a poly secondary-amide, has no sidechains and is a useful model system for generic polypeptide backbones. Results based on large-scale molecular dynamics simulations show that polyglycine forms compact, albeit disordered, globules in water and swollen, disordered coils in 8 M urea. There is minimal overlap between conformational ensembles in the two environments. Analysis of order parameters derived from theories for flexible polymers show that water at ambient temperatures is a poor solvent for generic polypeptide backbones. Therefore, the experimentally observed preferences for polyglutamine and glycine-serine block copolypeptides must originate, at least partially, in polypeptide backbones. A preliminary analysis of the driving forces that lead to distinct conformational preferences for polyglycine in two different environments is presented. Implications for describing conformational ensembles of generic IDP sequences are also discussed.

  19. Carter constant induced mechanism for generation of anisotropic kinetic equilibria in collisionless N-body systems (United States)

    Cremaschini, Claudio; Stuchlík, Zdeněk

    A new intrinsically-relativistic kinetic mechanism for generation of nonisotropic relativistic kinetic equilibria in collisionless N-body systems is pointed out. The theory is developed in the framework of the covariant Vlasov statistical description. The new effect is based on the constraints placed by the conservation laws of neutral single-particle dynamics in prescribed background curved-spacetimes demonstrating existence of Killing tensors. As an illustration, the particular case of the Kerr spacetime admitting the so-called Carter constant for the particle geodesic motion is considered. The general functional form of the equilibrium kinetic distribution function (KDF) is determined and an explicit realization in terms of Gaussian-like distributions is provided. It is shown that, due to the Carter constant, these equilibrium KDFs exhibit an anisotropic phase-space functional dependence in terms of the single-particle 4-velocity components, giving rise to corresponding nonisotropic continuum fluid fields. The qualitative properties of the equilibrium stress-energy tensor associated with these systems are discussed, with a particular emphasis on the related occurrence of temperature anisotropy effects. The theory is susceptible of astrophysical applications, including in particular the statistical properties of dark matter (DM) halos around stellar-mass or galactic-center black holes.

  20. Theory of equilibria of elastic braids with applications to DNA supercoiling (United States)

    van der Heijden, Gert; Starostin, Eugene


    Motivated by supercoiling of DNA and other filamentous structures, we formulate a new theory for equilibria of 2-braids, i.e., structures formed by two elastic rods winding around each other in continuous contact and subject to a local interstrand interaction. Unlike in previous work no assumption is made on the shape of the contact curve. Rather, this shape is solved for. The theory is developed in terms of a moving frame of directors attached to one of the strands with one of the directors pointing to the position of the other strand. The constant-distance constraint is automatically satisfied by the introduction of what we call braid strains. The price we pay is that the potential energy involves arclength derivatives of these strains, thus giving rise to a second-order variational problem. The Euler-Lagrange equations for this problem give balance equations for the overall braid force and moment referred to the moving frame as well as differential equations that can be interpreted as effective constitutive relations encoding the effect that the second strand has on the first as the braid deforms under the action of end loads. Both open braid and closed braid solutions (links and knots) are computed and current applications to DNA supercoiling are discussed. Research supported by EPSRC and HFSP.

  1. Exploring fluctuations and phase equilibria in fluid mixtures via Monte Carlo simulation (United States)

    Denton, Alan R.; Schmidt, Michael P.


    Monte Carlo simulation provides a powerful tool for understanding and exploring thermodynamic phase equilibria in many-particle interacting systems. Among the most physically intuitive simulation methods is Gibbs ensemble Monte Carlo (GEMC), which allows direct computation of phase coexistence curves of model fluids by assigning each phase to its own simulation cell. When one or both of the phases can be modelled virtually via an analytic free energy function (Mehta and Kofke 1993 Mol. Phys. 79 39), the GEMC method takes on new pedagogical significance as an efficient means of analysing fluctuations and illuminating the statistical foundation of phase behaviour in finite systems. Here we extend this virtual GEMC method to binary fluid mixtures and demonstrate its implementation and instructional value with two applications: (1) a lattice model of simple mixtures and polymer blends and (2) a free-volume model of a complex mixture of colloids and polymers. We present algorithms for performing Monte Carlo trial moves in the virtual Gibbs ensemble, validate the method by computing fluid demixing phase diagrams, and analyse the dependence of fluctuations on system size. Our open-source simulation programs, coded in the platform-independent Java language, are suitable for use in classroom, tutorial, or computational laboratory settings.

  2. Extremism without extremists: Deffuant model with emotions (United States)

    Sobkowicz, Pawel


    The frequent occurrence of extremist views in many social contexts, often growing from small minorities to almost total majority, poses a significant challenge for democratic societies. The phenomenon can be described within the sociophysical paradigm. We present a modified version of the continuous bounded confidence opinion model, including a simple description of the influence of emotions on tolerances, and eventually on the evolution of opinions. Allowing for psychologically based correlation between the extreme opinions, high emotions and low tolerance for other people's views leads to quick dominance of the extreme views within the studied model, without introducing a special class of agents, as has been done in previous works. This dominance occurs even if the initial numbers of people with extreme opinions is very small. Possible suggestions related to mitigation of the process are briefly discussed.

  3. Non-extremal branes

    Directory of Open Access Journals (Sweden)

    Pablo Bueno


    Full Text Available We prove that for arbitrary black brane solutions of generic Supergravities there is an adapted system of variables in which the equations of motion are exactly invariant under electric–magnetic duality, i.e. the interchange of a given extended object by its electromagnetic dual. We obtain thus a procedure to automatically construct the electromagnetic dual of a given brane without needing to solve any further equation. We apply this procedure to construct the non-extremal (p,q-string of Type-IIB String Theory (new in the literature, explicitly showing how the dual (p,q-five-brane automatically arises in this construction. In addition, we prove that the system of variables used is suitable for a generic characterization of every double-extremal Supergravity brane solution, which we perform in full generality.

  4. Extremes in nature

    CERN Document Server

    Salvadori, Gianfausto; Kottegoda, Nathabandu T


    This book is about the theoretical and practical aspects of the statistics of Extreme Events in Nature. Most importantly, this is the first text in which Copulas are introduced and used in Geophysics. Several topics are fully original, and show how standard models and calculations can be improved by exploiting the opportunities offered by Copulas. In addition, new quantities useful for design and risk assessment are introduced.

  5. Optical correlation

    NARCIS (Netherlands)

    Boden, J.A.


    A survey is given of the most common types of coherent optical correlators, which are classified as spatial plane correlators, frequency plane correlators and special reference correlators. Only the spatial plane correlators are dealt with rather thoroughly. Basic principles, some special features,

  6. Wind simulation for extreme and fatigue loads

    Energy Technology Data Exchange (ETDEWEB)

    Nielsen, M.; Larsen, G.C.; Mann, J.; Ott, S.; Hansen, K.S.; Pedersen, B.J.


    Measurements of atmospheric turbulence have been studied and found to deviate from a Gaussian process, in particular regarding the velocity increments over small time steps, where the tails of the pdf are exponential rather than Gaussian. Principles for extreme event counting and the occurrence of cascading events are presented. Empirical extreme statistics agree with Rices exceedence theory, when it is assumed that the velocity and its time derivative are independent. Prediction based on the assumption that the velocity is a Gaussian process underpredicts the rate of occurrence of extreme events by many orders of magnitude, mainly because the measured pdf is non-Gaussian. Methods for simulation of turbulent signals have been developed and their computational efficiency are considered. The methods are applicable for multiple processes with individual spectra and probability distributions. Non-Gaussian processes are simulated by the correlation-distortion method. Non-stationary processes are obtained by Bezier interpolation between a set of stationary simulations with identical random seeds. Simulation of systems with some signals available is enabled by conditional statistics. A versatile method for simulation of extreme events has been developed. This will generate gusts, velocity jumps, extreme velocity shears, and sudden changes of wind direction. Gusts may be prescribed with a specified ensemble average shape, and it is possible to detect the critical gust shape for a given construction. The problem is formulated as the variational problem of finding the most probable adjustment of a standard simulation of a stationary Gaussian process subject to relevant event conditions, which are formulated as linear combination of points in the realization. The method is generalized for multiple correlated series, multiple simultaneous conditions, and 3D fields of all velocity components. Generalization are presented for a single non-Gaussian process subject to relatively

  7. [The extremely violent child]. (United States)

    Berger, M; Bonneville, E


    More and more children have extremely violent behaviour which appears about the age of 15-16 months, when walking makes their hands free. This violence is individual, can appear suddenly at anytime, and is not accompanied by guilt. It is caused by early psychological and repeated traumas, whose importance is usually underestimated: unpredictable, violent parents, exposure to the spectacle of conjugal violence, distortion of the signals emitted by the toddler. These traumas bring about specific psychological structure. The prevention of these troubles exists but is impossible to realise in France.

  8. Extreme Programming Pocket Guide

    CERN Document Server



    Extreme Programming (XP) is a radical new approach to software development that has been accepted quickly because its core practices--the need for constant testing, programming in pairs, inviting customer input, and the communal ownership of code--resonate with developers everywhere. Although many developers feel that XP is rooted in commonsense, its vastly different approach can bring challenges, frustrations, and constant demands on your patience. Unless you've got unlimited time (and who does these days?), you can't always stop to thumb through hundreds of pages to find the piece of info

  9. Mycetoma of lower extremity

    Directory of Open Access Journals (Sweden)

    Sahariah S


    Full Text Available Ten cases of mycetoma of the lower extremity were seen and treated at the Postgraduate Institute of Medical Education & Research, Chandigarh, India, during the years 1973 to 1975. Six were treated by conservative method e.g. antibiotics, sulfonamides and immobilization of the part while remaining four were submitted t o surgery. Four out o f six from the first group had recurrence and has been put on second line of therapy. Recurrence occurred in only one case from the second group and he required an above knee amputation while the remaining three are free of disease and are well rehabilitated.

  10. Explaining unexpected data via competitive equilibria and processes in radical reactions with reversible deactivation. (United States)

    Konkolewicz, Dominik; Krys, Pawel; Matyjaszewski, Krzysztof


    lead to an acceleration of the reaction during the initial period. Similarly, in Cu mediated atom transfer radical polymerization (ATRP) with initiators for continuous radical regeneration (ICAR) initiated by a conventional radical initiator, the rate of polymerization should not depend on either the alkyl halide concentration or the Cu concentration. However, experiments show that the rate could be 10 times faster with alkyl halide than without alkyl halide. Finally, in aqueous media, the presence of active alkyl halides can appear to stop the disproportionation of Cu(I) complexes. These unusual data point to a more complex mechanism than originally envisioned, and in fact all these counterintuitive observations can be explained by the concept of competing equilibria and processes. In these cases, the presence of two or more reactions competing for the same reagent typically causes one pathway to dominate, while the rate of the other pathways are diminished. Alternatively, the competing pathways and processes can cause one or more reversible or pseudoreversible reactions to be imbalanced and lead to products distinct from the case where rates of forward and reverse reactions are balanced. In this Account, the concept of competitive processes and equilibria is developed and used to explain each of the unusual observations highlighted above.

  11. Composite circulation index of weather extremes (the example for Poland

    Directory of Open Access Journals (Sweden)

    Zbigniew Ustrnul


    Full Text Available The paper describes the implementation of a composite circulation index of weather extremes (CIE. The new index informs about the synoptic conditions favoring the occurrence of extremes on a regional scale. It was evaluated for temperature and precipitation extremes for Poland. Daily homogenized data obtained from 14 weather stations, which cover most of the country, were used. The data used cover the 60-year period from 1951 to 2010. The index is based on relationships between extremes and mesoscale circulation conditions. The core material also included data describing circulation types for the study period. Three different calendars were used (Grosswetterlagen, by Lity?ski, by Nied?wied?. The conditional probability of the occurrence of extremes for particular types was calculated independently using partial indices (Partial Index of weather Extremes ? PIE. The higher the index values, the more favorable the synoptic situation for the occurrence of extremes. The results were grouped by describing the probability of temperature and precipitation extremes on the IPCC likelihood scale. Three thresholds corresponding to the frequency of an occurrence were identified via a seasonal approach. The CIE was validated using basic correlation coefficients as well as contingency tables based on feature-displacement criteria and Bayesian Probability Methods. The results confirmed the significance of atmospheric circulation in the formation of temperature and precipitation extremes in Poland. The CIE proved the relationship by trying to estimate the probability of temperature and precipitation extremes occurrence depending on the circulation type forecasted.

  12. Multi-Equilibria Regulation Agent-Based Model of Opinion Dynamics in Social Networks

    Directory of Open Access Journals (Sweden)

    Andreas Koulouris


    Full Text Available This article investigates the Multiple Equilibria Regulation (MER model, i.e., an agent-based simulation model, to represent opinion dynamics in social networks. It relies on a small set of micro-prerequisites (intra-individual balance and confidence bound, leading to emergence of (nonstationary macro-outcomes. These outcomes may refer to consensus, polarization or fragmentation of opinions about taxation (e.g., congestion pricing or other policy measures, according to the way communication is structured. In contrast with other models of opinion dynamics, it allows for the impact of both the regulation of intra-personal discrepancy and the interpersonal variability of opinions on social learning and network dynamics. Several simulation experiments are presented to demonstrate, through the MER model, the role of different network structures (complete, star, cellular automata, small-world and random graphs on opinion formation dynamics and the overall evolution of the system. The findings can help to identify specific topological characteristics, such as density, number of neighbourhoods and critical nodes-agents, that affect the stability and system dynamics. This knowledge can be used to better organize the information diffusion and learning in the community, enhance the predictability of outcomes and manage possible conflicts. It is shown that a small-world organization, which depicts more realistic aspects of real-life and virtual social systems, provides increased predictability and stability towards a less fragmented and more manageable grouping of opinions, compared to random networks. Such macro-level organizations may be enhanced with use of web-based technologies to increase the density of communication and public acceptability of policy measures.

  13. Extracellular mercury sequestration by exopolymeric substances produced by Yarrowia spp.: Thermodynamics, equilibria, and kinetics studies. (United States)

    Oyetibo, Ganiyu Oladunjoye; Miyauchi, Keisuke; Suzuki, Hitoshi; Ishikawa, Satoru; Endo, Ginro


    Exopolymeric substances (EPS) produced by highly mercury-resistant strains of the yeast Yarrowia spp. (Idd1 and Idd2) were isolated and studied for their mercury binding potential. Excellent yield (approximately 0.3 g EPS per gram biomass) of soluble EPS in medium with 3% glucose was observed in the Yarrowia cultures 7 day post-inoculation. A gram dry weight of the EPS consists mainly of carbohydrates (0.4 g), protein (0.3-0.4 g), uronic acid (0.02 g), and nucleic acids (0.002 g). Mercury interactions with the biopolymer were measured as uptake kinetics from a simulated aquatic system and modelled with thermodynamics and calculated mass action equilibria. The EPS forms a complex with Hg(2+) in water with small activation energy (≤2 kJ mol(-1)), achieving about 30 mg Hg(2+) adsorption per gram dry weight of EPS. The adsorption models confirmed complexation of Hg(2+) by the EPS via heterogeneous multilayer adsorption that obey second-order kinetics at constant rate of 4.0 and 8.1 mg g(-1) min(-1). The EPS used chemisorption as rate-limiting step that controls the uptake of Hg(2+) from aquatic systems during micro-precipitation as bio-removal strategy. The EPS are promising biotechnological tools to design bioreactors for treatment of mercury-rich industrial wastewater. Copyright © 2016 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  14. High-throughput determination of adsorption equilibria for chromatographic oligosaccharide separations. (United States)

    Chilamkurthi, Sreekanth; Willemsen, Jan-Hein; van der Wielen, Luuk A M; Poiesz, Edwin; Ottens, Marcel


    Adsorption equilibria of the saccharides d-glucose, d-galactose, l-arabinose, lactose and a sugar acid were measured on gel-type sulfonated poly (styrene-co-divinylbenzene) strong cation exchange resins in a high-throughput (HT) 96-well plate batch uptake mode using a pipetting robot at 25 °C. Four different ionic forms, Ca(2+), K(+), Na(+), and H(+) were used. Single component adsorption isotherms were determined in a concentration range of 10-240 mg ml(-1). Multicomponent experiments were performed to investigate competitive adsorption in a concentration range of 10-120 mg ml(-1). A qualitative investigation on competitive and cooperative effects was performed. All sugar isotherms showed a linear behavior except for the sugar acid which showed an unfavorable (anti-Langmuir) behavior in the high concentration ranges. Selectivity values were determined from the binary mixture partition coefficient (K) values of each component. This HT 96-well plate batch uptake method proves to be less laborious and consumes less time and material compared to the frontal analysis and adsorption-desorption methods where column experimentation is used. Ternary mixture separation of arabinose and the sugar acid from glucose showed K(+) and Ca(2+) loaded resins having the best selectivity (DIAION Ca(2+) 2.01 and 1.78 for l-arabinose/d-glucose and sugar acid/l-arabinose respectively), similarly Purolite K(+) loaded resin for the lactose separation from glucose and galactose (1.17 for lactose/d-glucose). Column experiments were performed to validate the batch uptake experiments. The static binding results could easily be translated to the column experiments with good agreement. Finally, adding to the validity of the approach, binary and ternary fixed-bed experiments were well described by a dynamic mathematical chromatographic model using the parameters obtained from the binary-component isotherm data. Copyright © 2012 Elsevier B.V. All rights reserved.

  15. Fluid-rock interaction: mineral stability, mineral equilibria, and the propagation of metastable phases (United States)

    Harlov, D.


    The role of fluids in promoting mineral equilibria as a function of P-T-X has been documented for a variety of mineral systems both in nature as well as experimentally. In each of these cases, the rate at which equilibration occurs depends on fluid-mineral reactivity and upon the subsequent rate of dissolution- reprecipitation of the participating mineral phases (cf. review in Putnis, 2002, Mineral Mag, 66, 689). In rocks without a fluid phase, equilibration between mineral phases is entirely diffusion controlled. As a consequence, complete equilibration tends not to occur. This can then lead to the propagation of metastable mineral phases far beyond their P-T-X stability field over geological time scales. Examples of fluid-induced re-equilibration in mineral systems include formation of monazite inclusions in fluorapatite (Harlov et al., 2005, Contrib Mineral Petrol, 150, 268), metasomatically induced replacement of plagioclase by K-feldspar (Putnis et al., 2006, Lithos, in press online), solid-state transformation of biotite and amphibole to pyroxenes (Harlov et al., 2006, J Petrol, 47, 3), formation of titantite reaction rims on ilmenite (Harlov et al., Lithos, 88, 72), and replacement of fluorapatite by Fe-bearing chlorapatite (Harlov et al., 2006, Eur J Mineral, 18, 233). In each of these examples, fluids of varying compositions, pH, and H2O activities are required to achieve both the re-equilibration of the mineral phases involved, via dissolution-reprecipitation, as well as whatever subsequent mass transfer may be required. In general this process, whether from nature or experimental, can be investigated on both the micron and nanometer scale utilizing a variety of techniques including SEM, TEM, EBSD, LA-ICPMS, SIMS and EMP analysis. Such procedures, coupled with textural analysis, then allows for a more complete understanding of fluid-rock interaction and mass transfer on scales ranging from nanometers to kilometers.

  16. Vapor-Liquid Equilibria of Imidazolium Ionic Liquids with Cyano Containing Anions with Water and Ethanol. (United States)

    Khan, Imran; Batista, Marta L S; Carvalho, Pedro J; Santos, Luís M N B F; Gomes, José R B; Coutinho, João A P


    Isobaric vapor-liquid equilibria of 1-butyl-3-methylimidazolium thiocyanate ([C4C1im][SCN]), 1-butyl-3-methylimidazolium dicyanamide ([C4C1im][N(CN)2]), 1-butyl-3-methylimidazolium tricyanomethanide ([C4C1im][C(CN)3]), and 1-ethyl-3-methylimidazolium tetracyanoborate ([C2C1im][B(CN)4]), with water and ethanol were measured over the whole concentration range at 0.1, 0.07, and 0.05 MPa. Activity coefficients were estimated from the boiling temperatures of the binary systems, and the data were used to evaluate the ability of COSMO-RS for describing these molecular systems. Aiming at further understanding the molecular interactions on these systems, molecular dynamics (MD) simulations were performed. On the basis of the interpretation of the radial and spatial distribution functions along with coordination numbers obtained through MD simulations, the effect of the increase of CN-groups in the IL anion in its capability to establish hydrogen bonds with water and ethanol was evaluated. The results obtained suggest that, for both water and ethanol systems, the anion [N(CN)2](-) presents the higher ability to establish favorable interactions due to its charge, and that the ability of the anions to interact with the solvent, decreases with further increasing of the number of cyano groups in the anion. The ordering of the partial charges in the nitrogen atoms from the CN-groups in the anions agrees with the ordering obtained for VLE and activity coefficient data.

  17. Fractional correlation. (United States)

    Mendlovic, D; Ozaktas, H M; Lohmann, A W


    Recently, optical interpretations of the fractional-Fourier-transform operator have been introduced. On the basis of this operator the fractional correlation operator is defined in two different ways that are both consistent with the definition of conventional correlation. Fractional correlation is not always a shift-invariant operation. This property leads to some new applications for fractional correlation as shift-variant image detection. A bulk-optics implementation of fractional correlation is suggested and demonstrated with computer simulations.

  18. Correlation of Concepts "Extremism" and "Terrorism" in Countering the Financing of Terrorism and Extremism (United States)

    Baisagatova, Diana B.; Kemelbekov, Saken T.; Smagulova, Diana A.; Kozhamberdiyeva, Aigul S.


    The main threats to world order are terrorist and extremist activities. On the world stage, countries unite into a coalition with the aim to increase the efficiency of the fight against terrorism. At the local level, the terrorist threat is fought by the security services. In order to prevent global human victims, which may arise as a result of…

  19. Experimental measurements of vapor-liquid equilibria of the H2O + CO2 + CH4 ternary system (United States)

    Qin, J.; Rosenbauer, R.J.; Duan, Zhenhao


    Reported are the experimental measurements on vapor-liquid equilibria in the H2O + CO2 + CH4 ternary system at temperatures from (324 to 375) K and pressures from (10 to 50) MPa. The results indicate that the CH4 solubility in the ternary mixture is about 10 % to 40 % more than that calculated by interpolation from the Henry's law constants of the binary system, H2O + CH4, and the solubility of CO2 is 6 % to 20 % more than what is calculated by the interpolation from the Henry's law constants of the binary mixture, H 2O + CO2. ?? 2008 American Chemical Society.

  20. High-pressure vapor-liquid equilibria for ethylene + 4-methyl-1-pentane and 1-butene + 1-hexene

    Energy Technology Data Exchange (ETDEWEB)

    Laugier, S. [Ecole Nationale Superieure de Chimie et Physique de Bordeaux, Talence (France); Richon, D. [Ecole Nationale Superieure des Mines de Paris, Fontainebleau (France)


    Isothermal vapor-liquid equilibria (VLE) for the ethylene + 4-methyl-1-pentene and 1-butene + 1-hexene binary systems were measured by the static method at several temperatures for pressures in the range (0.3 to 8.5) MPa. Representations of VLE data by the Soave and Peng-Robinson cubic equations of state are compared in both modes: predictive and binary parameter adjustment. As the two binary systems behave almost ideally, there is no significant difference between their representation qualities through both equations of state.

  1. Comparison of two association models (Elliott-Suresh-Donohue and simplified PC-SAFT) for complex phase equilibria of hydrocarbon-water and amine-containing mixtures

    DEFF Research Database (Denmark)

    Grenner, Andreas; Schmelzer, Jürgen; von Solms, Nicolas


    , and water. Furthermore, the predictive capabilities of the models are investigated for four ternary systems composed of these components, which exhibit complex liquid-liquid(-liquid) equilibria (LLLE). Various aspects of association models which have an influence in the results are studied for the PC......, both models perform overall similarly for the binary systems, although ESD shows a remarkably good behavior despite its simplicity and the use of only the two-site scheme for all associating compounds. The prediction of the LLE in the ternary systems water + octane + aniline and water + CHA + aniline......Two Wertheim-based association models, the simplified PC-SAFT and the Elliott-Suresh-Donohue (ESD) equation of state, are compared in this work for the description of vapor-liquid equilibria (VLE) and liquid-liquid equilibria (LLE) in binary systems of aniline, cyclohexylamine (CHA), hydrocarbons...

  2. Equation of state modeling of the phase equilibria of asymmetric CO2+n-alkane binary systems using mixing rules cubic with respect to mole fraction

    DEFF Research Database (Denmark)

    Cismondi, Martin; Mollerup, Jørgen M.; Zabaloy, Marcelo S.


    Both the equation of state (EOS) and the quadratic mixing rules proposed by van der Waals towards the end of the XIX century were enormous contributions to the understanding and modeling of fluids phase behavior. They set the basis for a consistent and useful representation of phase equilibria...... for a great diversity of mixtures. Nevertheless, the models for representing phase equilibria and physico-chemical properties of asymmetric systems may require more flexible mixing rules than the classical quadratic van der Waals (vdW) mixing rules or their equivalent (with regard to the number of available...... interaction parameters) in modern equations of state.In particular, the phase equilibria of binary mixtures containing CO2 and heavy n-alkanes have been studied by an important number of authors and using different types of models, achieving only partially accurate results and realizing the difficulties...

  3. Nonstationary modeling of extreme precipitation in China (United States)

    Gao, Meng; Mo, Dingyuan; Wu, Xiaoqing


    The statistical methods based on extreme value theory have been traditionally used in meteorology and hydrology for a long time. Due to climate change and variability, the hypothesis of stationarity in meteorological or hydrological time series was usually not satisfied. In this paper, a nonstationary extreme value analysis was conducted for annual maximum daily precipitation (AMP) at 631 meteorological stations over China for the period 1951-2013. Stationarity of all 631 AMP time series was firstly tested using KPSS test method, and only 48 AMP time series showed non-stationarity at 5% significance level. The trends of these 48 nonstationary AMP time series were further tested using M-K test method. There were 25 nonstationary AMP time series mainly distributed in southern and western China showing significant positive trend at 5% level. Another 5 nonstationary AMP time series with significant negative trends were near northern urban agglomeration, Sichuan Basin, and central China. For these nonstationary AMP time series with significant positive or negative trends, the location parameter in generalized extreme value (GEV) distribution was assumed to be time-varying, and the trends were successfully characterized by the nonstationary GEV models. For the remaining 18 nonstationary AMP time series mainly in the eastern portion of China, no significant trend was detected. The correlation analysis showed that only 5 nonstationary AMP time series were significantly correlated with one or two of the four climate indices EASMI, WPI, SOI, and PDO. Then, the location and scale parameters in the GEV distribution were modeled as functions of the significantly correlated climate indices. The modeling results in this study showed that the nonstationary GEV distributions performed better than their stationary equivalents. Finally, 20-year and 50-year return levels of precipitation extremes at all 631 stations were estimated using the best fitting distribution for the year 1961

  4. Statistics of Local Extremes

    DEFF Research Database (Denmark)

    Larsen, Gunner Chr.; Bierbooms, W.; Hansen, Kurt Schaldemose


    The gust events described in the IEC-standard are formulated as coherent gusts of an inherent deterministic character, whereas the gusts experienced in real situation are of a stochastic nature with a limited spatial extension. This conceptual differencemay cause substantial differences in the load......, 1996]. However, dealing with wind turbine design, not only detailed knowledge on the spatial/time structure of the gust event is required. The probabilityof occurrence of a gust event with a given wind speed amplitude/magnitude is equally important. This theme is addressed in the present report......"Modelling of Extreme Gusts for Design Calculations " (NEWGUST), which is co-funded through JOULEIII on contract no. JOR3-CT98-0239....

  5. Moving in extreme environments:extreme loading; carriage versus distance


    Lucas, Samuel J. E.; Helge, Jørn W.; Schütz, Uwe H W; Goldman, Ralph F.; Cotter, James D


    This review addresses human capacity for movement in the context of extreme loading and with it the combined effects of metabolic, biomechanical and gravitational stress on the human body. This topic encompasses extreme duration, as occurs in ultra-endurance competitions (e.g. adventure racing and transcontinental races) and expeditions (e.g. polar crossings), to the more gravitationally limited load carriage (e.g. in the military context). Juxtaposed to these circumstances is the extreme met...

  6. Lower extremity injuries in snowboarding. (United States)

    Ishimaru, Daichi; Ogawa, Hiroyasu; Sumi, Hiroshi; Sumi, Yasuhiko; Shimizu, Katsuji


    In snowboarding, the upper extremity is known as the most common injury site and little information is available for lower extremity injuries. Here, we aim to discuss lower extremity injuries during snowboarding. We retrospectively analyzed the epidemiologic factors, injury types, and injury mechanisms for injured snowboarders (7,793 cases) between 2004-2005 and 2008-2009 seasons; information was gathered via questionnaires. Individuals were classified into a lower extremity injury group (961 cases) and a control group with other injuries (6,832 cases). The incidence of lower extremity injuries in snowboarding was 0.16 per 1,000 participant days, accounting for 12.3% of all snowboarding injuries. The mean age of the lower extremity injury group and injured control group was 26.1 years ± 5.9 years and 25.1 years ± 5.6 years, respectively. Approximately 90% of snowboarders in both the groups were equipped with soft-shelled boots. Skilled snowboarders tended to sustain lower extremity injuries (psnowboarding is lacerations/contusions caused by collision with other snow sport participants. Lower extremity injuries in snowboarding differ considerably from well-known upper extremity injuries in terms of injury types and mechanisms. The incidence of lower extremity injuries is high and deserves further attention. Copyright © 2011 by Lippincott Williams & Wilkins

  7. Overview of the biology of extreme events (United States)

    Gutschick, V. P.; Bassirirad, H.


    . Effects on water and N cycles are already marked. Adaptive responses of plants are very irregularly distributed among species and genotypes, most adaptive responses having been lost over 20 My of minimal or virtually accidental genetic selection for correlated traits. Offsets of plant activity from those of pollinators and pests may amplify direct physiological effects on plants. Another extreme of interest is the insect-mediated mass dieoff of conifers across western North America tied to a rare combination of drought and year-long high temperatures.

  8. Transport barriers in helical equilibria: structural change in the reversed field pinch (United States)

    Martin, Piero


    Self-organization of RFX plasmas in single helical axis equilibrium, with m=1,n=7 helicity, is a structural change for the reversed field pinch (RFP) [Lorenzini et al., Nature Phys 2009 doi:10.1038/nphys1308]. This happens at high plasma current (I>1 MA) while axisymmetric boundary conditions are enforced: the helical state has almost conserved magnetic flux surfaces, interpreted as ghost surfaces [Hudson&Breslau PRL 2008], leading to strong core electron transport barriers. Electron temperature Te reaches 1.3keV @1.7MA. Ion temperature Ti is ˜(0.5-0.75)Te, consistent with collisional ion heating. The core barrier extends up to ˜0.65r/a. Magnetic surfaces quality improves with Lundquist number S, thanks to the simultaneous decrease of magnetic chaos and increase of the helical field strength. Helical equilibria are reconstructed by the 3d code VMEC. The (1,7) helicity acts to hold the core safety factor almost flat and below 1/7. The barrier foot coincides with a zero magnetic shear region, where density of rational surfaces is minimum, as in other configurations. Plasma-wall interaction is smoother. Main gas particle confinement time improves in pellet-fuelled plasmas, with record value ˜10ms. No core impurity accumulation is evident in Laser Blow Off experiments, which is consistent with numerical simulation results. High current sets a transition also for the edge, where robust Te gradients are observed with a pedestal of ˜1keV in ˜3cm, possibly due to improved magnetic topology and synergic with core barrier. As persistence and quality of these improved helical states increase with current, the likelihood of achieving steady helical multi-MA RFPs can be inferred. RFX experiments allow a study of the beneficial effects of non-axisymmetric shaping and may provide a platform for a more general validation of theoretical tools developed for stellarators. Moreover, these results are transformational in supporting the RFP as a low-external field, non

  9. Effect of Fluorine on Near-Liquidus Phase Equilibria of Basalts (United States)

    Filiberto, Justin; Wood, Justin; Loan, Le; Dasgupta, Rajdeep; Shimizu, Nobumichi; Treiman, Allan H.


    Volatile species such as H2O, CO2, F, and Cl have significant impact in generation and differentiation of basaltic melts. Thus far experimental work has primarily focused on the effect of water and carbon dioxide on basalt crystallization, liquid-line of descent, and mantle melting [e.g., 1, 2] and the effects of halogens have received far less attention [3-4]. However, melts in the planetary interiors can have non-negligible chlorine and fluorine concentrations. Here, we explore the effects of fluorine on near-liquidus phase equilibria of basalt. We have conducted nominally anhydrous piston cylinder experiments using graphite capsules at 0.6 - 1.5 GPa on an Fe-rich model basalt composition. 1.75 wt% fluorine was added to the starting mix in the form of AgF2. Fluorine in the experimental glass was measured by SIMS and major elements of glass and minerals were analyzed by EPMA. Nominally volatile free experiments yield a liquidus temperature from 1330 C at 0.8GPa to 1400 at 1.6GPa and an olivine(Fo72)-pyroxene(En68)-liquid multiple saturation point at 1.25 GPa and 1375 C. The F-bearing experiments yield a liquiudus temperature from 1260 C at 0.6GPa to 1305 at 1.5GPa and an ol(Fo66)-pyx(En64)-MSP at 1 GPa and 1260 C. This shows that F depresses the basalt liquidus, extends the pyroxene stability field to lower pressure, and forces the liquidus phases to be more Fe-rich. KD(Fe-Mg/mineral-melt) calculated for both pyroxenes and olivines show an increase with increasing F content of the melt. Therefore, we infer that F complexes with Mg in the melt and thus increases the melt s silica activity, depressing the liquidus and changing the composition of the crystallizing minerals. Our study demonstrates that on a weight percent basis, the effect of fluorine is similar to the effect of H2O [1] and Cl [3] on freezing point depression of basalts. But on an atomic fraction basis, the effect of F on liquidus depression of basalts is xxxx compared to the effect of H. Future

  10. Review of algorithms for modeling metal distribution equilibria in liquid-liquid extraction processes

    Directory of Open Access Journals (Sweden)

    Lozano, L. J.


    Full Text Available This work focuses on general guidelines to be considered for application of least-squares routines and artificial neural networks (ANN in the estimation of metal distribution equilibria in liquid-liquid extraction process. The goal of the procedure in the statistical method is to find the values of the equilibrium constants (Kj for the reactions involved in the metal extraction which minimizes the differences between experimental distribution coefficient (Dexp and theoretical distribution coefficients according to the mechanism proposed (Dtheor- In the first part of the article, results obtained with the most frequently routine reported in the bibliography are compared with those obtained using the algorithms previously discussed. In the second part, the main features of a single back-propagation neural network for the same purpose are discussed, and the results obtained are compared with those obtained with the classical methods.

    El trabajo presenta las líneas generales a considerar para la estimación del equilibrio de distribución de metales en procesos de extracción líquido-líquido, según dos métodos: algoritmo clásico de mínimos cuadrados y redes neuronales artificiales. El objetivo del procedimiento, en el caso del método estadístico, es encontrar los valores de las constantes de equilibrio (Kj para las reacciones involucradas en la extracción del metal, que minimizan las diferencias entre el coeficiente de distribución experimental y el coeficiente de distribución teórico, de acuerdo al mecanismo propuesto. En la primera parte del artículo se comparan los resultados obtenidos a partir de los algoritmos usados más habitualmente en la bibliografía, con los datos obtenidos mediante el algoritmo previamente descrito. En la segunda parte, se presentan las características fundamentales para aplicar una red neuronal sencilla con algoritmo back-propagation y los

  11. The effect of chemical and organic amendments on sodium exchange equilibria in a calcareous sodic soil. (United States)

    Ranjbar, Faranak; Jalali, Mohsen


    In this study, the reclamation of a calcareous sodic soil with the exchangeable sodium percentage (ESP) value of 26.6% was investigated using the cheap and readily available chemical and organic materials including natural bentonite and zeolite saturated with calcium (Ca2+), waste calcite, three metal oxide nanoparticles functionalized with an acidic extract of potato residues, and potato residues. Chemical amendments were added to the soil at a rate of 2%, while potato residues were applied at the rates of 2 and 4% by weight. The ESP in the amended soils was reduced in the range of 0.9-4.9% compared to the control soil, and the smallest and the largest decline was respectively observed in treatments containing waste calcite and 4% of potato residues. Despite the reduction in ESP, the values of this parameter were not below 15% at the end of a 40-day incubation period. So, the effect of solutions of varying sodium adsorption ratio (SAR) values of 0, 5, 10, 20, 30, 40, and 50 on sodium (Na+) exchange equilibria was evaluated in batch systems. The empirical models (simple linear, Temkin, and Dubinin-Radushkevich) fitted well to experimental data. The relations of quantity to intensity (Q/I) revealed that the potential buffering capacity for Na+ (PBCNa) varied from 0.275 to 0.337 ((cmolc kg(-1)) (mmol L(-1))(-1/2)) in the control soil and amended soils. The relationship between exchangeable sodium ratio (ESR) and SAR was individually determined for the control soil and amended soils. The values of Gapon selectivity coefficient (KG) of Na+ differed from the value suggested by U.S. Salinity Laboratory (USSL). The PHREEQC, a geochemical computer program, was applied to simulate Na+ exchange isotherms by using the mechanistic cation exchange model (CEM) along with Gaines-Thomas selectivity coefficients. The simulation results indicated that Na+ exchange isotherms and Q/I and ESR-SAR relations were influenced by the type of counter anions. The values of K G increased in

  12. Solution Equilibria between Aluminum(III) Ion and L-histidine or L-tyrosine (United States)

    Jelic, Ratomir; Dzajevic, Dragana; Cvijovic, Mirjana


    Toxic effects due to high aluminum body loads were observed in a number of conditions following ingestion of Al-containing antacids. Bio-availability of aluminum depends not only on the solubility of the ingested salt but also on the physico-chemical properties of the soluble Al complexes formed in body fluids. Amino acids may, upon interaction with Al-salts, form absorbable Al-complexes. Hence, complex formation equilibria between Al3+ and either, L- histidine or L-tyrosine were studied by glass electrode potentiometric (0.1 mol/L LiCl ionic medium, 298 K), proton NMR and uv spectrophotometric measurements. Non linear least squares treatment of the potentiometric data indicates that in the concentration ranges: 0.5≤CA1≤2.0 ; 1.0≤CHis≤10.0; 2.5≤PH≤6.5, in Al3+ + His solutions, the following complexes (with log overall stability constants given in parenthesis) are formed: Al(HHis)3+(12.21±0.08); Al(His)2+, (7.25±0.08); and Al(HHis)His2+, (20.3±0.1). In Al3+ + Tyr solutions in the concentration range 1.0≤CTyr≤3.0 mmol/L and ligand to metal concentration ratio from 2:1 to 3:1, in the pH interval from 3.0 to 6.5 the formation of the following complexes was detected: Al(HTyr)2+, (12.72±0.09); Al(Tyr)2+, (10.16±0.03) and Al(OH)2Tyr , (2.70±0.05). Proton NMR data indicate that in Al(His)2+ complex histidine acts as a monodentate ligand but its bidentate coordination is possible with carboxylate oxygen and imidazole 1-nitrogen as donors. In Al(HTyr)3+ complex tyrosine is a monodentate ligand with carboxylate oxygen as donor. The mechanism of the formation of complexes in solution is discussed as well as their possible role in aluminum toxicity. PMID:18476000

  13. Extreme winds in Denmark

    Energy Technology Data Exchange (ETDEWEB)

    Kristensen, L.; Rathmann, O.; Hansen, S.O.


    Wind-speed data from four sites in Denmark have been analyzed in order to obtain estimates of the basic wind velocity which is defined as the 50-year wind speed under standard conditions, i.e. ten-minute averages at the height 10 m over a uniform terrain with the roughness length 0.05 m. The sites are, from west, Skjern (15 years), Kegnaes (7 years), Sprogoe (20 years), and Tystofte (15 years). The data are ten minute averages of wind speed, wind direction, temperature and pressure. The last two quantities are used to determine the air density {rho}. The data are cleaned for terrain effects by means of a slightly modified WASP technique where the sector speed-up factors and roughness lengths are linearly smoothed with a direction resolution of one degree. Assuming geotropic balance, all the wind-velocity data are transformed to friction velocity u{sub *} and direction at standard conditions by means of the geotropic drag law for neutral stratification. The basic wind velocity in 30 deg. sectors are obtained through ranking of the largest values of the friction velocity pressure 1/2{rho}u{sub *}{sup 2} taken both one every two months and once every year. The main conclusion is that the basic wind velocity is significantly larger at Skjern, close to the west coast of Jutland, than at any of the other sites. Irrespective of direction, the present standard estimates of 50-year wind are 25 {+-} 1 m/s at Skern and 22 {+-} 1 m/s at the other three sites. These results are in agreement with those obtained by Jensen and Franck (1970) and Abild (1994) and supports the conclusion that the wind climate at the west coast of Jutland is more extreme than in any other part of the country. Simple procedures to translate in a particular direction sector the standard basic wind velocity to conditions with a different roughness length and height are presented. It is shown that a simple scheme makes it possible to calculate the total 50-year extreme load on a general structure without

  14. Statistical Model of Extreme Shear

    DEFF Research Database (Denmark)

    Larsen, Gunner Chr.; Hansen, Kurt Schaldemose


    (PDF) of turbulence driven short-term extreme wind shear events, conditioned on the mean wind speed, for an arbitrary recurrence period. The model is based on an asymptotic expansion, and only a few and easily accessible parameters are needed as input. The model of the extreme PDF is supplemented...... by a model that, on a statistically consistent basis, describe the most likely spatial shape of an extreme wind shear event. Predictions from the model have been compared with results from an extreme value data analysis, based on a large number of high-sampled full-scale time series measurements...... are consistent, given the inevitabel uncertainties associated with model as well as with the extreme value data analysis. Keywords: Statistical model, extreme wind conditions, statistical analysis, turbulence, wind loading, statistical analysis, turbulence, wind loading, wind shear, wind turbines....

  15. Liquid–liquid equilibria in the quinary aqueous two-phase system of poly(ethylene glycol) 6000 + sodium sulfate + water in the presence of glucose and ethanol: Experimental investigation and thermodynamic modeling

    Energy Technology Data Exchange (ETDEWEB)

    Hekayati, Javad; Roosta, Aliakbar, E-mail:; Javanmardi, Jafar


    Highlights: • Quinary LLE phase equilibria involving PEG 6000 + Na{sub 2}SO{sub 4} + H{sub 2}O + glucose + ethanol. • Favorable partition coefficients of ethanol and glucose. • Satisfactory correlation of the LLE experimental data with the original NRTL model. • Root mean squared deviations (RMSDs) of less than 0.6%. - Abstract: Extractive fermentation processes involving aqueous two-phase systems (ATPSs) are considered as viable means of overcoming the problems associated with product inhibition. Practical development of these processes requires accurate knowledge of the liquid–liquid equilibrium (LLE) of the ATPS forming components alongside the substrate and product of the fermentation process. In this work, the quinary aqueous two-phase LLE of poly(ethylene glycol) 6000 + sodium sulfate + water in the presence of glucose and ethanol have been experimentally determined at 298.15 K using spectrophotometric methods. The resulting LLE data were then satisfactorily correlated by the non-random two-liquid (NRTL) activity coefficient model based on mass fractions. In doing so, the binary energy interaction parameters of the NRTL activity coefficient model were obtained and reported. Calculated RMS deviations below 0.6% demonstrate that the original NRTL activity coefficient model can accurately correlate the LLE data of the quinary aqueous biphasic system of interest.

  16. Detectors in Extreme Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Blaj, G. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Carini, G. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Carron, S. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Haller, G. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Hart, P. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Hasi, J. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Herrmann, S. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Kenney, C. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Segal, J. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Tomada, A. [SLAC National Accelerator Lab., Menlo Park, CA (United States)


    Free Electron Lasers opened a new window on imaging the motion of atoms and molecules. At SLAC, FEL experiments are performed at LCLS using 120Hz pulses with 1012 - 1013 photons in 10 femtoseconds (billions of times brighter than the most powerful synchrotrons). This extreme detection environment raises unique challenges, from obvious to surprising. Radiation damage is a constant threat due to accidental exposure to insufficiently attenuated beam, focused beam and formation of ice crystals reflecting the beam onto the detector. Often high power optical lasers are also used (e.g., 25TW), increasing the risk of damage or impeding data acquisition through electromagnetic pulses (EMP). The sample can contaminate the detector surface or even produce shrapnel damage. Some experiments require ultra high vacuum (UHV) with strict design, surface contamination and cooling requirements - also for detectors. The setup is often changed between or during experiments with short turnaround times, risking mechanical and ESD damage, requiring work planning, training of operators and sometimes continuous participation of the LCLS Detector Group in the experiments. The detectors used most often at LCLS are CSPAD cameras for hard x-rays and pnCCDs for soft x-rays.

  17. Historical trend of hourly extreme rainfall in Peninsular Malaysia (United States)

    Syafrina, A. H.; Zalina, M. D.; Juneng, L.


    Hourly rainfall data between the years 1975 and 2010 across the Peninsular Malaysia were analyzed for trends in hourly extreme rainfall events. The analyses were conducted on rainfall occurrences during the northeast monsoon (November-February) known as NEM, the southwest monsoon (May-August) known as SWM, and the two inter-monsoon seasons, i.e., March-April (MA) and September-October (SO). Several extreme rainfall indices were calculated at the station level. The extreme rainfall events in Peninsular Malaysia showed an increasing trend between the years 1975 and 2010. The trend analysis was conducted using linear regression; no serial correlation was detected from the Durbin-Watson test. Ordinary kriging was used to determine the spatial patterns of trends in seasonal extremes. The total amount of rainfall received during NEM is higher compared to rainfall received during inter-monsoon seasons. However, intense rainfall is observed during the inter-monsoon season with higher hourly total amount of rainfall. The eastern part of peninsular was most affected by stratiform rains, while convective rain contributes more precipitation to areas in the western part of the peninsular. From the distribution of spatial pattern of trend, the extreme frequency index (Freq >20) gives significant contribution to the positive extreme rainfall trend during the monsoon seasons. Meanwhile, both extreme frequency and extreme intensity (24-Hr Max, Freq >95th, Tot >95th, Tot >99th, and Hr Max) indices give significant contribution to the positive extreme rainfall trend during the inter-monsoon seasons. Most of the significant extreme indices showed the positive sign of trends. However, a negative trend of extreme rainfall was found in the northwest coast due to the existence of Titiwangsa Range. The extreme intensity, extreme frequency, and extreme cumulative indices showed increasing trends during the NEM and MA while extreme intensity and extreme frequency had similar trends during

  18. Density, viscosity and phase equilibria study of {ethylsulfate-based ionic liquid + water} binary systems as a function of temperature and composition

    Energy Technology Data Exchange (ETDEWEB)

    Królikowska, Marta, E-mail:; Lipiński, Paweł; Maik, Daria


    Highlights: • The [EMPIP][EtSO{sub 4}], [EMMOR][EtSO{sub 4}], [EMPYR][EtSO{sub 4}] and its aqueous mixtures have been studied. • The density, dynamic viscosity and SLE have been determined. • The excess molar volumes and viscosity deviations have been calculated. • The NRTL, Wilson, UNIQUAC, Redlich–Kister and VFT equations have been used to correlate the experimental data. - Abstract: This paper is a continuation of our investigation on physicochemical and thermodynamic properties of ionic liquids and its aqueous solutions. In this work the density, ρ and dynamic viscosity, η have been determined for binary mixtures of the ionic liquids: 1-ethyl-1-methyl-piperidinium ethylsulfate, [EMPIP][EtSO{sub 4}], 1-ethyl-1-methylmorpholinium ethylsulfate, [EMMOR][EtSO{sub 4}] and 1-ethyl-1-methylpyrrolidinium ethylsulfate, [EMPYR][EtSO{sub 4}] with water at wide temperature and composition range at atmospheric pressure. From experimental values of the density, ρ and dynamic viscosity, η the excess molar volumes, V{sup E} and viscosity deviations, Δη were calculated and correlated using Redlich–Kister polynomial equation. The (solid + liquid) phase equilibria, SLE for the tested binary mixtures have been determined by well-known dynamic method at a wide range of composition and temperature at atmospheric pressure. For comparison, the SLE data for {[EMPYR][EtSO_4] + water} binary mixtures have been determined using DSC technique. The experimental SLE data have been correlated by means of NRTL, UNIQUAC and Wilson equations. Additionally, the basic thermal properties of the pure ILs, that is, the glass-transition temperature, T{sub g,1} as well as the heat capacity at the glass-transition temperature, ΔC{sub p(g),1}, melting temperature, T{sub m} and enthalpy of melting, Δ{sub m}H have been measured using a differential scanning microcalorimetry technique (DSC). Decomposition of the ILs was detected by the simultaneous TG/DTA experiments. The choice of the

  19. Likelihood estimators for multivariate extremes

    KAUST Repository

    Huser, Raphaël


    The main approach to inference for multivariate extremes consists in approximating the joint upper tail of the observations by a parametric family arising in the limit for extreme events. The latter may be expressed in terms of componentwise maxima, high threshold exceedances or point processes, yielding different but related asymptotic characterizations and estimators. The present paper clarifies the connections between the main likelihood estimators, and assesses their practical performance. We investigate their ability to estimate the extremal dependence structure and to predict future extremes, using exact calculations and simulation, in the case of the logistic model.

  20. Extremeness of meteorological variables as an indicator of extreme precipitation events (United States)

    Müller, Miloslav; Kašpar, Marek; Řezáčová, Daniela; Sokol, Zbyněk


    Extreme large-scale precipitation events in central Europe are determined by the synoptic pattern, which is typically characterized by cyclones moving from the south into this region. Herein, we demonstrate that this synoptic pattern is accompanied by large-scale anomalies of dynamic and thermodynamic variables that occur in specific regions before or during the precipitation event. The extremeness of individual variables was evaluated by ERA-40 data relative to the corresponding climatology by the obtained distribution function values. Precipitation events leading to 14 significant summer floods in the period between 1958 and 2002 were used as reference events. The temporal correspondence of the anomalies among reference events was employed by selecting 26 synoptic predictors of extreme precipitation in the Czech Republic. A predictor evaluates the extremeness of a variable in a limited area on a specific day relatively to the start of the precipitation event (day D). While the predictors cover a five-day period from D - 2 to D + 2, most are relevant to the days with precipitation (from D to D + 2). The predictors cannot be considered individually because only opportune coincidences make the synoptic situations dangerous. In the present study, a combined EM index was used by evaluating the predictors as a whole, without considering their relationships. Days with minimum EM values correspond to significant flood events in the Czech Republic. Our results confirm that the synoptic pattern can be properly characterized by the extremeness of selected dynamic and thermodynamic variables, and that the anomalies are distinctly correlated with the extremity of large-scale precipitation and flood events in the Czech Republic. This approach is applicable to other regions where precipitation is significantly related to large-scale synoptic patterns, and could be employed also by operational detection of upcoming extreme precipitation events.

  1. ExtremeBounds: Extreme Bounds Analysis in R

    Directory of Open Access Journals (Sweden)

    Marek Hlavac


    Full Text Available This article introduces the R package ExtremeBounds to perform extreme bounds analysis (EBA, a sensitivity test that examines how robustly the dependent variable of a regression model is related to a variety of possible determinants. ExtremeBounds supports Leamer's EBA that focuses on the upper and lower extreme bounds of regression coefficients, as well as Sala-i-Martin's EBA which considers their entire distribution. In contrast to existing alternatives, it can estimate models of a variety of user-defined sizes, use regression models other than ordinary least squares, incorporate non-linearities in the model specification, and apply custom weights and standard errors. To alleviate concerns about the multicollinearity and conceptual overlap of examined variables, ExtremeBounds allows users to specify sets of mutually exclusive variables, and can restrict the analysis to coefficients from regression models that yield a variance inflation factor within a prespecified limit.

  2. Influence of Climate Oscillations on Extreme Precipitation in Texas (United States)

    Bhatia, N.; Singh, V. P.; Srivastav, R. K.


    Much research in the field of hydroclimatology is focusing on the impact of climate variability on hydrologic extremes. Recent studies show that the unique geographical location and the enormous areal extent, coupled with extensive variations in climate oscillations, have intensified the regional hydrologic cycle of Texas. The state-wide extreme precipitation events can actually be attributed to sea-surface pressure and temperature anomalies, such as Bermuda High and Jet Streams, which are further triggered by such climate oscillations. This study aims to quantify the impact of five major Atlantic and Pacific Ocean related climate oscillations: (i) Atlantic Multidecadal Oscillation (AMO), (ii) North Atlantic Oscillation (NAO), (iii) Pacific Decadal Oscillation (PDO), (iv) Pacific North American Pattern (PNA), and (v) Southern Oscillation Index (SOI), on extreme precipitation in Texas. Their respective effects will be determined for both climate divisions delineated by the National Climatic Data Centre (NCDC) and climate regions defined by the Köppen Climate Classification System. This study will adopt a weighted correlation approach to attain the robust correlation coefficients while addressing the regionally variable data outliers for extreme precipitation. Further, the variation of robust correlation coefficients across Texas is found to be related to the station elevation, historical average temperature, and total precipitation in the months of extremes. The research will shed light on the relationship between precipitation extremes and climate variability, thus aiding regional water boards in planning, designing, and managing the respective systems as per the future climate change.

  3. Extreme Environments: Why NASA? (United States)

    Meyer, M. A.


    Life on our planet is the only known example in the universe and so we are relegated to this planet for the study of life. However, life may be a natural consequence of planet formation, and so the study of the origin, evolution, distribution and future of life may be greatly informed by planetary exploration. Astrobiology has adopted several approaches to study life on Earth, for deducing our origins, for determining the likelihood of life elsewhere, and for enabling the search for evidence of past or present life. The first approach has been the Exobiology Program, centered around understanding the origins of life and which supports individual investigator research. Second has been the construction of consortia-type research in which researchers from different disciplines focus on a larger problem. This structure began with NASA Specialized Centers of Research and Training and has grown to include the Astrobiology Institute - a collection of competitively selected groups of researchers attacking problems in Astrobiology as individual teams and as a consolidated Institute. With the formation of an intellectual basis for exploring for life elsewhere, Astrobiology has initiated the competitive research and development program in instrument development (Astrobiology Science and Technology for Instrument Development [ASTID] Program) that would enable future mission instruments for the exploration of planetary bodies in the search for prebiotic chemistry, habitable environments (past or present), biomarkers, and possibly life itself. However, the act of exploring requires robust instrumentation, mobile robotic platforms, efficient operations, and a high level of autonomy. To this end, Astrobiology has started a new research activity that promotes scientifically-driven robotic exploration of extreme environments on Earth that are analogous to suspected habitable environments on other planetary bodies. The program is called Astrobiology Science and Technology for

  4. Surprising Impact of Remote Groups on the Folding-Unfolding and Dimer-Chain Equilibria of Bifunctionl H-Bonding Unimers

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Rui; Cheng, Shuang; Baker, Erin Shammel; Smith, Richard D.; Zeng, Xiao Cheng; Gong, Bing


    Oligoamide 1, consisting of two H-bonding units linked by a trimethylene linker, was previously found to form a very stable, folded dimer. In this work, replacing the side chains and end groups of 1 led to derivatives that show the surprising impact of end groups on the folding and dimer-chain equilibria of the resultant molecules.

  5. Vapor Pressure Plus: An Experiment for Studying Phase Equilibria in Water, with Observation of Supercooling, Spontaneous Freezing, and the Triple Point (United States)

    Tellinghuisen, Joel


    Liquid-vapor, solid-vapor, and solid-liquid-vapor equilibria are studied for the pure substance water, using modern equipment that includes specially fabricated glass cells. Samples are evaporatively frozen initially, during which they typically supercool to -5 to -10 [degrees]C before spontaneously freezing. Vacuum pumping lowers the temperature…

  6. Modelling the phase equilibria of multicomponent mixtures containing CO2, alkanes, water, and/or alcohols using the quadrupolar CPA equation of state

    DEFF Research Database (Denmark)

    Bjørner, Martin Gamel; Kontogeorgis, Georgios


    In this work, a quadrupolar cubic plus association (qCPA) equation of state is evaluated for its ability to predict the phase equilibria of multicomponent mixtures containing CO2 and alkanes, alcohols, and/or water. A single binary interaction parameter is employed in qCPA for all binary...

  7. Oxygen equilibria and ligand binding kinetics of erythrocruorins from two burrowing polychaetes of different modes of life, Marphysa sanguinea and Diopatra cuprea

    DEFF Research Database (Denmark)

    Weber, Roy E.; Bonaventura, J.; Sullivan, B.


    Oxygen equilibria, ligand-binding kinetics and some other physicochemical properties are reported for erythrocruorins of two intertidal polychaetes:Marphysa sanguinea, which inhabits simple, relatively stagnant burrows, andDiopatra cuprea, which inhabits impermeable, parchment-like tubes that are...

  8. Thermodynamic characteristics of the acid-base equilibria of ethylenediamine- N, N'-diglutaric acid in aqueous solutions using calorimetric data (United States)

    Gridchin, S. N.; Nikol'skii, V. M.


    The enthalpies of reaction of betaine group neutralization of ethylenediamine- N, N'-diglutaric acid (H4L) at 298.15 K and at different values of ionic strength of 0.1, 0.5, 1.0 (KNO3) is measured by direct calorimetry. The standard thermodynamic characteristics of the protolytic equilibria of H4L are calculated.

  9. Phase equilibria in subducting basaltic crust: implications for H 2O release from the slab (United States)

    Forneris, Juliette F.; Holloway, John R.


    Fluids released from subducting slabs induce partial melting of the mantle wedge above the slab, which in turn is responsible for arc volcanism at the Earth's surface. The partially hydrated basaltic layer of the slab is a potential source of these fluids and a major reservoir for H 2O at depth. Constraining the stability domains of hydrous phases and the position of the dehydration reactions in this system in pressure-temperature ( P- T) space is essential to describe and quantify the fluid release from subducting oceanic crust into the overlying mantle wedge. Experiments were conducted in the ranges of 2.2-3.4 GPa and 625-750°C to determine phase equilibria in an H 2O-saturated natural basalt at conditions relevant to subduction zones. The experimental duration was typically 1 month, although some experiments were replicated with a shorter run duration (1-2 weeks) in order to identify potentially metastable phases. A mixture of a natural mid-ocean ridge basalt (MORB) glass and mineral seeds was used as the starting material. Oxygen fugacity was buffered within ±1.3 log units of nickel-bunsenite (NiNiO). The results obtained show that a calcic amphibole (barroisite) is stable from 2.2 to about 2.4 GPa. At 2.6 GPa, it is replaced by a sodic amphibole (near end-member glaucophane), which is stable up to 3 GPa at 625°C. This high-pressure assemblage constitutes a true analog of a natural amphibole-bearing eclogite and the first synthesis of glaucophane from a rock of basaltic composition. As opposed to the results of previous studies on basaltic compositions [A.R. Pawley, J.R. Holloway, Science 260 (1993) 664-667; S. Poli, Am. J. Sci. 293 (1993) 1061-1107; S. Poli, M.W. Schmidt, J. Geophys. Res. 100 (1995) 22299-22314; M.W. Schmidt, S. Poli, Earth Planet. Sci. Lett. 163 (1998) 361-379], chloritoid is present only as a metastable phase in the pressure-temperature range investigated here. Metastability of chloritoid in earlier experiments, due to short run duration

  10. Potentiometric investigation of acid dissociation and anionic homoconjugation equilibria of substituted phenols in dimethyl sulfoxide[Substituted phenols; Acid-base equilibria; Dimethyl sulfoxide (DMSO); Potentiometry

    Energy Technology Data Exchange (ETDEWEB)

    Czaja, Malgorzata; Kozak, Anna; Makowski, Mariusz; Chmurzynski, Lech. E-mail:


    Standard acidity constants, K{sub a}{sup DMSO} (HA), expressed as pK{sub a}{sup DMSO} (HA) values, and anionic homoconjugation constants, K{sup DMSO}{sub AHA{sup -}}, (in the form of lg K{sup DMSO}{sub AHA{sup -}} values) have been determined for 11 substituted phenol-phenolate systems a polar protophilic aprotic solvent, dimethyl sulfoxide (DMSO) with a potentiometric titration. A linear relationship has been determined between lg K{sup DMSO}{sub AHA{sup -}} and pK{sub a}{sup DMSO} (HA). The tendency towards anionic homoconjugation in these systems increases with increasing pK{sub a}{sup DMSO} (HA) that is with declining phenol acidity. The pK{sub a}{sup DMSO} (HA) are correlated with both pK{sub a}{sup W} (HA) water and other polar non-aqeous solvents.

  11. Influence of temperature on the (liquid + liquid) equilibria of {l_brace}3-methyl pentane + cyclopentane + methanol{r_brace} ternary system at T = (293.15, 297.15, and 299.15) K

    Energy Technology Data Exchange (ETDEWEB)

    Gramajo de Doz, Monica B. [Departamento de Fisica, Facultad de Ciencias Exactas y Tecnologia, Universidad Nacional de Tucuman, Avenida Independencia 1800, 4000 Tucuman (Argentina)], E-mail:; Cases, Alicia M.; Bonatti, Carlos M.; Solimo, Horacio N. [Departamento de Fisica, Facultad de Ciencias Exactas y Tecnologia, Universidad Nacional de Tucuman, Avenida Independencia 1800, 4000 Tucuman (Argentina)


    In order to show the influence of temperature on the (liquid + liquid) equilibria (LLE) of the {l_brace}3-methyl pentane (1) + cyclopentane (2) + methanol (3){r_brace} ternary system, equilibrium results at T = (293.15, 297.15, and 299.15) K are reported. The effect of the temperature on the (liquid + liquid) equilibrium is determined and discussed. Experimental results show that this ternary system is completely homogeneous beyond T = 300 K. All chemicals were quantified by gas chromatography using a thermal conductivity detector. The tie line results were satisfactorily correlated by the Othmer and Tobias method, and the plait point coordinates for the three temperatures were estimated. Experimental values for the ternary system are compared with values calculated by the NRTL and UNIQUAC equations, and predicted by means of the UNIFAC group contribution method. It is found that the UNIQUAC and NRTL models provide similar good correlations of the solubility curve at these three temperatures. Finally, the UNIFAC model predicts binodal band type curves in the range of temperatures studied here, similar to those observed for systems classified by Treybal as type 2, instead of type 1 as experimentally observed. Distribution coefficients were also analysed through distribution curves.

  12. Evolution caused by extreme events. (United States)

    Grant, Peter R; Grant, B Rosemary; Huey, Raymond B; Johnson, Marc T J; Knoll, Andrew H; Schmitt, Johanna


    Extreme events can be a major driver of evolutionary change over geological and contemporary timescales. Outstanding examples are evolutionary diversification following mass extinctions caused by extreme volcanism or asteroid impact. The evolution of organisms in contemporary time is typically viewed as a gradual and incremental process that results from genetic change, environmental perturbation or both. However, contemporary environments occasionally experience strong perturbations such as heat waves, floods, hurricanes, droughts and pest outbreaks. These extreme events set up strong selection pressures on organisms, and are small-scale analogues of the dramatic changes documented in the fossil record. Because extreme events are rare, almost by definition, they are difficult to study. So far most attention has been given to their ecological rather than to their evolutionary consequences. We review several case studies of contemporary evolution in response to two types of extreme environmental perturbations, episodic (pulse) or prolonged (press). Evolution is most likely to occur when extreme events alter community composition. We encourage investigators to be prepared for evolutionary change in response to rare events during long-term field studies.This article is part of the themed issue 'Behavioural, ecological and evolutionary responses to extreme climatic events'. © 2017 The Author(s).

  13. Spatial dependence of extreme rainfall (United States)

    Radi, Noor Fadhilah Ahmad; Zakaria, Roslinazairimah; Satari, Siti Zanariah; Azman, Muhammad Az-zuhri


    This study aims to model the spatial extreme daily rainfall process using the max-stable model. The max-stable model is used to capture the dependence structure of spatial properties of extreme rainfall. Three models from max-stable are considered namely Smith, Schlather and Brown-Resnick models. The methods are applied on 12 selected rainfall stations in Kelantan, Malaysia. Most of the extreme rainfall data occur during wet season from October to December of 1971 to 2012. This period is chosen to assure the available data is enough to satisfy the assumption of stationarity. The dependence parameters including the range and smoothness, are estimated using composite likelihood approach. Then, the bootstrap approach is applied to generate synthetic extreme rainfall data for all models using the estimated dependence parameters. The goodness of fit between the observed extreme rainfall and the synthetic data is assessed using the composite likelihood information criterion (CLIC). Results show that Schlather model is the best followed by Brown-Resnick and Smith models based on the smallest CLIC's value. Thus, the max-stable model is suitable to be used to model extreme rainfall in Kelantan. The study on spatial dependence in extreme rainfall modelling is important to reduce the uncertainties of the point estimates for the tail index. If the spatial dependency is estimated individually, the uncertainties will be large. Furthermore, in the case of joint return level is of interest, taking into accounts the spatial dependence properties will improve the estimation process.

  14. Changing precipitation extremes in Europe (United States)

    van den Besselaar, E. J. M.; Klein Tank, A. M. G.; van der Schrier, G.


    A growing number of studies indicate trends in precipitation extremes over Europe during recent decades. These results are generally based on descriptive indices of extremes which occur on average once (or several times) each year (or season). An example is the maximum one-day precipitation amount per year. Extreme value theory complements the descriptive indices, in order to evaluate the intensity and frequency of more rare events. Trends in more rare extremes are difficult to detect, because per definition only few events exist in the observational series. Although single extreme events cannot be simply and directly attributed to anthropogenic climate change, as there is always a finite chance that the event in question might have occurred naturally, the odds may have shifted to make some of them more likely than in an unchanging climate (IPCC, 2007). In this study we focus on climate extremes defined as rare events within the statistical reference distribution of rainfall that is monitored daily at a particular place. We examine the daily precipitation series from the European Climate Assessment and Dataset (ECA&D) project. Comparisons will be made between the trends in modest extremes detected using the descriptive indices and the trends in more rare extremes determined by fitting an extreme value distribution to the data in consecutive 20-yr periods of the record. The trends in multi-year return levels are determined for groups of stations in several subregions of Europe. Because the typical record length is about 50 yr, we will assess the trends in events that occur on average up to once in 50 yr.

  15. Optimized Mie potentials for phase equilibria: Application to noble gases and their mixtures with n-alkanes. (United States)

    Mick, Jason R; Soroush Barhaghi, Mohammad; Jackman, Brock; Rushaidat, Kamel; Schwiebert, Loren; Potoff, Jeffrey J


    Transferrable force fields, based on n-6 Mie potentials, are presented for noble gases. By tuning the repulsive exponent, ni, it is possible to simultaneously reproduce experimental saturated liquid densities and vapor pressures with high accuracy, from the normal boiling point to the critical point. Vapor-liquid coexistence curves for pure fluids are calculated using histogram reweighting Monte Carlo simulations in the grand canonical ensemble. For all noble gases, saturated liquid densities and vapor pressures are reproduced to within 1% and 4% of experiment, respectively. Radial distribution functions, extracted from NVT and NPT Monte Carlo simulations, are in similarly excellent agreement with experimental data. The transferability of the optimized force fields is assessed through calculations of binary mixture vapor-liquid equilibria. These mixtures include argon + krypton, krypton + xenon, methane + krypton, methane + xenon, krypton + ethane, and xenon + ethane. For all mixtures, excellent agreement with experiment is achieved without the introduction of any binary interaction parameters or multi-body interactions.

  16. Coevolution of slow-fast populations: evolutionary sliding, evolutionary pseudo-equilibria and complex Red Queen dynamics. (United States)

    Dercole, F; Ferrière, R; Gragnani, A; Rinaldi, S


    We study the interplay of ecological and evolutionary dynamics in communities composed of populations with contrasting time-scales. In such communities, genetic variation of individual traits can cause population transitions between stationary and cyclic ecological regimes, hence abrupt variations in fitness. Such abrupt variations raise ridges in the adaptive landscape, where the populations are poised between equilibrium and cyclic coexistence and along which evolutionary trajectories can remain sliding for long times or halt at special points called evolutionary pseudo-equilibria. These novel phenomena should be generic to all systems in which ecological interactions cause fitness to vary discontinuously. They are demonstrated by the analysis of a predator-prey community, with one adaptive trait for each population. The eco-evolutionary dynamics of the system show a number of other distinctive features, including evolutionary extinction and two forms of Red Queen dynamics. One of them is characterized by intermittent bouts of cyclic oscillations of the two populations.

  17. Modeling phase equilibria of alkanols with the simplified PC-SAFT equation of state and generalized pure compound parameters

    DEFF Research Database (Denmark)

    Grenner, Andreas; Kontogeorgis, Georgios; von Solms, Nicolas


    The simplified PC-SAFT equation of state has been applied to liquid-liquid, vapor-liquid and solid-liquid equilibria for mixtures containing 1-or 2-alkanols with alkanes, aromatic hydrocarbons, CO2 and water. For the alkanols we use generalized pure compound parameters. This means that two...... the pure compound parameters is usually based on fitting to saturated vapor pressure and liquid density data over an extended temperature range. However, such data are rarely available for complex compounds. To verify the new pure compound parameters, comparisons to ordinary optimized alkanol parameters......, where all five pure compound parameters were fitted to experimental liquid density and vapor pressure data, were made. The results show that the new generalized alkanol parameters from this work perform at least as well as other alkanol parameter sets. (c) 2007 Elsevier B.V. All rights reserved....

  18. Basic principles of electrolyte chemistry for microfluidic electrokinetics. Part II: Coupling between ion mobility, electrolysis, and acid-base equilibria. (United States)

    Persat, Alexandre; Suss, Matthew E; Santiago, Juan G


    We present elements of electrolyte dynamics and electrochemistry relevant to microfluidic electrokinetics experiments. In Part I of this two-paper series, we presented a review and introduction to the fundamentals of acid-base chemistry. Here, we first summarize the coupling between acid-base equilibrium chemistry and electrophoretic mobilities of electrolytes, at both infinite and finite dilution. We then discuss the effects of electrode reactions on microfluidic electrokinetic experiments and derive a model for pH changes in microchip reservoirs during typical direct-current electrokinetic experiments. We present a model for the potential drop in typical microchip electrophoresis device. The latter includes finite element simulation to estimate the relative effects of channel and reservoir dimensions. Finally, we summarize effects of electrode and electrolyte characteristics on potential drop in microfluidic devices. As a whole, the discussions highlight the importance of the coupling between electromigration and electrophoresis, acid-base equilibria, and electrochemical reactions.

  19. Basic principles of electrolyte chemistry for microfluidic electrokinetics. Part I: Acid-base equilibria and pH buffers. (United States)

    Persat, Alexandre; Chambers, Robert D; Santiago, Juan G


    We review fundamental and applied acid-base equilibrium chemistry useful to microfluidic electrokinetics. We present elements of acid-base equilibrium reactions and derive rules for pH calculation for simple buffers. We also present a general formulation to calculate pH of more complex, arbitrary mixtures of electrolytes, and discuss the effects of ionic strength and temperature on pH calculation. More practically, we offer advice on buffer preparation and on buffer reporting. We also discuss "real world" buffers and likely contamination sources. In particular, we discuss the effects of atmospheric carbon dioxide on buffer systems, namely, the increase in ionic strength and acidification of typical electrokinetic device buffers. In Part II of this two-paper series, we discuss the coupling of acid-base equilibria with electrolyte dynamics and electrochemistry in typical microfluidic electrokinetic systems.

  20. Development of long-lived radionuclides partitioning technology - Experimental/theoretical study of phase equilibria for multicomponent multiphase systems

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Chul Soo; Lee, Se Il; Sim, Yeon Sik; Park, Sung Bin; Yang, Sung Oh; Park, Ji Yong [Korea University, Seoul (Korea, Republic of)


    In various partitioning processes, rare earth elements and actinide elements are separated from other elements in the first stage. They are then separated into rare earth groups and actinde groups. The first stage is accomplished by solvent extraction using DEHPA, by precipitation using oxalic= acid, or by cation exchange. The second stage is carried out by selective back-extraction or by selective elution using DTPA. In these processes the equilibria is governed by the concentrations of nitric acid, of solvents, and of precipitants among others. In this study various distribution coefficients in partitioning processes were experimentally determined. And thermodynamic models were proposed to calculate distribution coefficients with experimentally determined equilibrium constants. 32 refs., 11 tabs., 23 figs. (author)

  1. Modeling phase equilibria for acid gas mixtures using the CPA equation of state. Part II: Binary mixtures with CO2

    DEFF Research Database (Denmark)

    Tsivintzelis, Ioannis; Kontogeorgis, Georgios; Michelsen, Michael Locht


    In Part I of this series of articles, the study of H2S mixtures has been presented with CPA. In this study the phase behavior of CO2 containing mixtures is modeled. Binary mixtures with water, alcohols, glycols and hydrocarbons are investigated. Both phase equilibria (vapor–liquid and liquid......–liquid) and densities are considered for the mixtures involved. Different approaches for modeling pure CO2 and mixtures are compared. CO2 is modeled as non self-associating fluid, or as self-associating component having two, three and four association sites. Moreover, when mixtures of CO2 with polar compounds (water...... for binary mixtures of CO2 and water or alcohols when the solvation between CO2 and the polar compound is explicitly accounted for, whereas the model is less satisfactory when CO2 is treated as self-associating compound....

  2. Microelectrode voltammetry of multi-electron transfers complicated by coupled chemical equilibria: a general theory for the extended square scheme. (United States)

    Laborda, Eduardo; Gómez-Gil, José María; Molina, Angela


    A very general and simple theoretical solution is presented for the current-potential-time response of reversible multi-electron transfer processes complicated by homogeneous chemical equilibria (the so-called extended square scheme). The expressions presented here are applicable regardless of the number of electrons transferred and coupled chemical processes, and they are particularized for a wide variety of microelectrode geometries. The voltammetric response of very different systems presenting multi-electron transfers is considered for the most widely-used techniques (namely, cyclic voltammetry, square wave voltammetry, differential pulse voltammetry and steady state voltammetry), studying the influence of the microelectrode geometry and the number and thermodynamics of the (electro)chemical steps. Most appropriate techniques and procedures for the determination of the 'interaction' between successive transfers are discussed. Special attention is paid to those situations where homogeneous chemical processes, such as protonation, complexation or ion association, affect the electrochemical behaviour of the system by different stabilization of the oxidation states.

  3. Simulation of phase equilibria and interfacial properties of binary mixtures on the liquid-vapour interface using lattice sums (United States)

    López-Lemus, Jorge; Alejandre, José

    Molecular dynamics simulations of Lennard-Jones binary mixtures were performed to obtain phase equilibria and thermodynamic properties for the liquid-vapour interface. The dispersion interactions were handled using the lattice sum method where the full interaction is obtained and there is no requirement for any long range correction to the properties. The application of the method using the Lorentz-Berthelot combining rule for unlike interactions is discussed. The coexisting densities, adsorption of molecules at the interface and surface tension are the main results of this work. Coexisting properties were compared with Gibbs ensemble Monte Carlo results and with those of the grand canonical Monte Carlo method combined with the histogram reweighting technique, and good agreement was found. The lattice sum method results were compared with those of the spherically truncated and shifted potential to analyse the truncation effect. The adsorption of molecules at the interface and surface tension increase with interaction.

  4. Prediction of vapor-liquid equilibria for the alcohol + glycerol systems using UNIFAC and modified UNIFAC (Dortmund) (United States)

    Hartanto, Dhoni; Mustain, Asalil; Nugroho, Febry Dwi


    The vapor-liquid equilibria for eight systems of alcohols + glycerol at 101.325 kPa have been predicted in this study using UNIFAC and Modified UNIFAC (Dortmund) group contribution methods. The investigated alcohols were methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 2-methyl-1-propanol and 2-methyl-2-propanol. In order to study the accuracy of both contribution methods, the predicted data obtained from both approaches were compared to the experimental data from the literature. The prediction accuracy using modified UNIFAC (Dortmund) give better results compared to the UNIFAC method for (ethanol, 1-propanol, 2-propanol and 1-butanol) + glycerol but UNIFAC method show better accuracy for methanol + glycerol system. In addition, the influences of carbon chain length on the phase behaviours of alcohol + glycerol systems were also discussed as well.

  5. Modeling the liquid-liquid equilibria of water plus fluorocarbons with the cubic-plus-association equation of state

    DEFF Research Database (Denmark)

    Oliveira, Mariana B.; Freire, Mara G.; Marrucho, Isabel M.


    dioxide, making them interesting for several biomedical applications. In most of these applications, water or aqueous systems are present for which the knowledge of the mutual solubilities between the fluorocarbons and the aqueous phases is important. In this work, the application of the cubic......-plus-association equation of state (CPA EoS) has been extended to binary mixtures of water with several linear, cyclic, aromatic, and substituted fluorocarbons. The CPA EoS was successfully used to model the liquid-liquid equilibria of aqueous mixtures that contain FCs, while also being able to describe the cross......-association phenomena between substituted and aromatic FCs and water. It is shown that, for aliphatic perfluorocarbons, CPA can be used without any mixture binary parameter to predict the water solubility....

  6. The Extreme Right Filter Bubble


    O'Callaghan, Derek; Greene, Derek; Conway, Maura; Carthy, Joe; Cunningham, Pádraig


    Due to its status as the most popular video sharing platform, YouTube plays an important role in the online strategy of extreme right groups, where it is often used to host associated content such as music and other propaganda. In this paper, we develop a categorization suitable for the analysis of extreme right channels found on YouTube. By combining this with an NMF-based topic modelling method, we categorize channels originating from links propagated by extreme right Twitter accounts. This...

  7. Transferable Potentials for Phase Equilibria. 4. United-Atom Description of Linear and Branched Alkenes and Alkylbenzenes

    Energy Technology Data Exchange (ETDEWEB)



    The Transferable Potentials for Phase Equilibria-United Atom (TraPPE-UA) force field for hydrocarbons is extended to alkenes and alkylbenzenes by introducing the following pseudo-atoms: CH{sub 2}(sp{sup 2}), CH(sp{sup 2}), CH(aro), R-C(aro) for the link to aliphatic side chains, and C(aro) for the link of two benzene rings. In this united-atom force field, the nonbonded interactions of the hydrocarbon pseudo-atoms are solely governed by Lennard-Jones 12-6 potentials, and the Lennard-Jones well depth and size parameters for the new pseudo-atoms were determined by fitting to the single-component vapor-liquid phase equilibria of a few selected model compounds. Configurational-bias Monte Carlo simulations in the NVT version of the Gibbs ensemble were carried out to calculate the single-component vapor-liquid coexistence curves for ethene, propene, 1-butene, trans- and cis-2-butene. 2-methylpropene, 1,5-hexadiene, 1-octene, benzene, toluene, ethylbenzene, propylbenzene, isopropylbenzene, o-, m-, and p-xylene, and naphthalene. The phase diagrams for the binary mixtures of (supercritical) ethene/n-heptane and benzene/n-pentane were determined from simulations in the NpT Gibbs ensemble. Although the TraPPE-UA force field is rather simple and makes use of relatively few different pseudo-atoms, its performance, as judged by comparisons to other popular force fields and available experimental data, is very satisfactory.

  8. Hall Sensors for Extreme Temperatures

    Directory of Open Access Journals (Sweden)

    Maciej Oszwaldowski


    Full Text Available We report on the preparation of the first complete extreme temperature Hall sensor. This means that the extreme-temperature magnetic sensitive semiconductor structure is built-in an extreme-temperature package especially designed for that purpose. The working temperature range of the sensor extends from −270 °C to +300 °C. The extreme-temperature Hall-sensor active element is a heavily n-doped InSb layer epitaxially grown on GaAs. The magnetic sensitivity of the sensor is ca. 100 mV/T and its temperature coefficient is less than 0.04 %/K. This sensor may find applications in the car, aircraft, spacecraft, military and oil and gas industries.

  9. Statistical Model of Extreme Shear

    DEFF Research Database (Denmark)

    Hansen, Kurt Schaldemose; Larsen, Gunner Chr.


    (PDF) of turbulence driven short-term extreme wind shear events, conditioned on the mean wind speed, for an arbitrary recurrence period. The model is based on an asymptotic expansion, and only a few and easily accessible parameters are needed as input. The model of the extreme PDF is supplemented...... by a model that, on a statistically consistent basis, describes the most likely spatial shape of an extreme wind shear event. Predictions from the model have been compared with results from an extreme value data analysis, based on a large number of full-scale measurements recorded with a high sampling rate......In order to continue cost-optimisation of modern large wind turbines, it is important to continuously increase the knowledge of wind field parameters relevant to design loads. This paper presents a general statistical model that offers site-specific prediction of the probability density function...

  10. Irrigation mitigates against heat extremes (United States)

    Thiery, Wim; Fischer, Erich; Visser, Auke; Hirsch, Annette L.; Davin, Edouard L.; Lawrence, Dave; Hauser, Mathias; Seneviratne, Sonia I.


    Irrigation is an essential practice for sustaining global food production and many regional economies. Emerging scientific evidence indicates that irrigation substantially affects mean climate conditions in different regions of the world. Yet how this practice influences climate extremes is currently unknown. Here we use gridded observations and ensemble simulations with the Community Earth System Model to assess the impacts of irrigation on climate extremes. While the influence of irrigation on annual mean temperatures is limited, we find a large impact on temperature extremes, with a particularly strong cooling during the hottest day of the year (-0.78 K averaged over irrigated land). The strong influence on hot extremes stems from the timing of irrigation and its influence on land-atmosphere coupling strength. Together these effects result in asymmetric temperature responses, with a more pronounced cooling during hot and/or dry periods. The influence of irrigation is even more pronounced when considering subgrid-scale model output, suggesting that local effects of land management are far more important than previously thought. Finally we find that present-day irrigation is partly masking GHG-induced warming of extreme temperatures, with particularly strong effects in South Asia. Our results overall underline that irrigation substantially reduces our exposure to hot temperature extremes and highlight the need to account for irrigation in future climate projections.

  11. Boolean Delay Equations: A Simple Way of Looking at Interactions and Extreme Events (United States)

    Ghil, Michael


    Boolean Delay Equations (BDEs) are semi-discrete dynamical models with Boolean-valued variables that evolve in continuous time. Systems of BDEs can be classified into conservative or dissipative, in a manner that parallels the classification of ordinary or partial differential equations. Solutions to certain conservative BDEs exhibit growth of complexity in time; such BDEs can be seen therefore as metaphors for biological evolution or human history. Dissipative BDEs are structurally stable and exhibit multiple equilibria and limit cycles, as well as more complex, fractal solution sets, such as Devil's staircases and ``fractal sunbursts.'' BDE systems have been used as highly idealized models of climate change on several time scales, as well as in earthquake modeling and prediction, and in genetics. BDEs with an infinite number of variables on a regular spatial grid have been called "partial BDEs" and we discuss connections with other types of discrete dynamical systems, including cellular automata and Boolean networks. We present recent BDE work on damage propagation in networks, with an emphasis on production-chain models. This formalism turns out to be well adapted to investigating propagation of an initial damage due to a climatic or other natural disaster. It thus serves to study economic impacts of extreme events, as well as extreme disruption of a network of interactions.

  12. Mangled lower extremity: can we trust the amputation scores? (United States)

    Fodor, Lucian; Sobec, Raluca; Sita-Alb, Laura; Fodor, Marius; Ciuce, Constantin


    Limb injuries represent a constant and severe problem. Several lower limb injuries are more frequent than upper limb injuries. Over time, in an attempt to quantify the severity of traumas and to establish guidelines for the decision whether to save or amputate a mangled extremity, several scoring systems have been reported. Most refer to bone fractures, soft tissue damage, vascular, nerves and tendon lesions. Articles dealing with mangled lower extremities published in the last 15 years were analyzed. Other inclusion criteriaincluded:articles reporting MESS, PSI, LSI, and Gustillo-Anderson scores, studies based on groups of more than 25 patients, and English language articles. We tried to determine if there was good correlation between amputation recommendations and various scores of injury, with regard to combat wounds and civilian injuries, in adult and pediatric groups. Thirty-two papers fulfilled our criteria; in 17 of these, correlation between mangled extremity scores and the decision to amputate or salvage the limb was well-defined. Good correlation between MESS and amputation was found in 25% of the papers. The highest correlation was found for pediatric injuries and combined adult and pediatric combat injuries. The mangled extremity is a long-lasting, unsolved problem, with much debate and a large number of protocols and scoring systems, but with no unanimously-accepted solution. Many mangled extremities are borderline cases, and the decision to amputate or to salvage a limb must be carefully assessed. With advances in the medical field over the last 15 years, more mangled lower extremities are salvaged, especially in civilian injuries.

  13. Ideologies and Discourses: Extreme Narratives in Extreme Metal Music

    Directory of Open Access Journals (Sweden)

    Bojana Radovanović


    Full Text Available Historically speaking, metal music has always been about provoking a strong reaction. Depending on the characteristics of different sub-genres, one can focus on the sound, technique, visual appearance, and furthermore, the ideologies and ideas that are the foundation for each of the sub-genres. Although the majority of the metal community rejects accusations of being racially intolerant, some ideologies of extreme sub-genres (such as black metal are in fact formed around the ideas of self-conscious elitism expressed through interest in pagan mythology, racism, Nazism and fascism. There has been much interest in the Nazi era within the extreme metal scene thus influencing other sub-genres and artists. The aim of this paper is to examine various appearances of extreme narratives such as Nazism and racism in  different sub-genres of metal, bearing in mind variations dependent on geographical, political, and other factors.

  14. Genetics Home Reference: paroxysmal extreme pain disorder (United States)

    ... Health Conditions paroxysmal extreme pain disorder paroxysmal extreme pain disorder Printable PDF Open All Close All Enable Javascript to view the expand/collapse boxes. Description Paroxysmal extreme pain disorder is a condition characterized by skin redness ...

  15. Changes of Extreme Climate Events in Latvia


    Avotniece, Z; Klavins, M; Rodinovs, V


    Extreme climate events are increasingly recognized as a threat to human health, agriculture, forestry and other sectors. To assess the occurrence and impacts of extreme climate events, we have investigated the changes of indexes characterizing positive and negative temperature extremes and extreme precipitation as well as the spatial heterogeneity of extreme climate events in Latvia. Trend analysis of long–term changes in the frequency of extreme climate events demonst...

  16. Rising Precipitation Extremes across Nepal

    Directory of Open Access Journals (Sweden)

    Ramchandra Karki


    Full Text Available As a mountainous country, Nepal is most susceptible to precipitation extremes and related hazards, including severe floods, landslides and droughts that cause huge losses of life and property, impact the Himalayan environment, and hinder the socioeconomic development of the country. Given that the countrywide assessment of such extremes is still lacking, we present a comprehensive picture of prevailing precipitation extremes observed across Nepal. First, we present the spatial distribution of daily extreme precipitation indices as defined by the Expert Team on Climate Change Detection, Monitoring and Indices (ETCCDMI from 210 stations over the period of 1981–2010. Then, we analyze the temporal changes in the computed extremes from 76 stations, featuring long-term continuous records for the period of 1970–2012, by applying a non-parametric Mann−Kendall test to identify the existence of a trend and Sen’s slope method to calculate the true magnitude of this trend. Further, the local trends in precipitation extremes have been tested for their field significance over the distinct physio-geographical regions of Nepal, such as the lowlands, middle mountains and hills and high mountains in the west (WL, WM and WH, respectively, and likewise, in central (CL, CM and CH and eastern (EL, EM and EH Nepal. Our results suggest that the spatial patterns of high-intensity precipitation extremes are quite different to that of annual or monsoonal precipitation. Lowlands (Terai and Siwaliks that feature relatively low precipitation and less wet days (rainy days are exposed to high-intensity precipitation extremes. Our trend analysis suggests that the pre-monsoonal precipitation is significantly increasing over the lowlands and CH, while monsoonal precipitation is increasing in WM and CH and decreasing in CM, CL and EL. On the other hand, post-monsoonal precipitation is significantly decreasing across all of Nepal while winter precipitation is decreasing

  17. Book review: Extreme ocean waves (United States)

    Geist, Eric L.


    Extreme Ocean Waves”, edited by E. Pelinovsky and C. Kharif, second edition, Springer International Publishing, 2016; ISBN: 978-3-319-21574-7, ISBN (eBook): 978-3-319-21575-4The second edition of “Extreme Ocean Waves” published by Springer is an update of a collection of 12 papers edited by Efim Pelinovsky and Christian Kharif following the April 2007 meeting of the General Assembly of the European Geosciences Union. In this edition, three new papers have been added and three more have been substantially revised. Color figures are now included, which greatly aids in reading several of the papers, and is especially helpful in visualizing graphs as in the paper on symbolic computation of nonlinear wave resonance (Tobisch et al.). A note on terminology: extreme waves in this volume broadly encompass different types of waves, including deep-water and shallow-water rogue waves (which are alternatively termed freak waves), and internal waves. One new paper on tsunamis (Viroulet et al.) is now included in the second edition of this volume. Throughout the book, the reader will find a combination of laboratory, theoretical, and statistical/empirical treatment necessary for the complete examination of this subject. In the Introduction, the editors underscore the importance of studying extreme waves, documenting a dramatic instance of damaging extreme waves that recently occurred in 2014.

  18. Extreme hydrological events and security

    Directory of Open Access Journals (Sweden)

    Z. W. Kundzewicz


    Full Text Available Economic losses caused by hydrological extremes – floods and droughts – have been on the rise, worldwide. Hydrological extremes jeopardize human security and cause serious threats to human life and welfare and societal livelihood. Floods and droughts can undermine societies' security, understood as freedom from threat and the ability of societies to maintain their independent identity and their functional integrity against forces of change. Several dimensions of security are reviewed in the context of hydrological extremes. Floods and droughts pose a burden and serious challenges to the state, responsible to sustain economic development, societal and environmental security – the maintenance of ecosystem services, on which a society depends. It is shown that reduction of risk of hydrological disasters improves human security.

  19. Functional metagenomics of extreme environments. (United States)

    Mirete, Salvador; Morgante, Verónica; González-Pastor, José Eduardo


    The bioprospecting of enzymes that operate under extreme conditions is of particular interest for many biotechnological and industrial processes. Nevertheless, there is a considerable limitation to retrieve novel enzymes as only a small fraction of microorganisms derived from extreme environments can be cultured under standard laboratory conditions. Functional metagenomics has the advantage of not requiring the cultivation of microorganisms or previous sequence information to known genes, thus representing a valuable approach for mining enzymes with new features. In this review, we summarize studies showing how functional metagenomics was employed to retrieve genes encoding for proteins involved not only in molecular adaptation and resistance to extreme environmental conditions but also in other enzymatic activities of biotechnological interest. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Extreme solar-terrestrial events (United States)

    Dal Lago, A.; Antunes Vieira, L. E.; Echer, E.; Balmaceda, L. A.; Rockenbach, M.; Gonzalez, W. D.


    Extreme solar-terrestrial events are those in which very energetic solar ejections hit the earth?s magnetosphere, causing intense energization of the earth?s ring current. Statistically, their occurrence is approximately once per Gleissberg solar cycle (70-100yrs). The solar transient occurred on July, 23rd (2012) was potentially one of such extreme events. The associated coronal mass ejection (CME), however, was not ejected towards the earth. Instead, it hit the STEREO A spacecraft, located 120 degrees away from the Sun-Earth line. Estimates of the geoeffectiveness of such a CME point to a scenario of extreme Space Weather conditions. In terms of the ring current energization, as measured by the Disturbance Storm-Time index (Dst), had this CME hit the Earth, it would have caused the strongest geomagnetic storm in space era.

  1. Adsorption equilibria of single gas and gas mixture on homogeneous surfaces. A unified approach based on statistical thermodynamics developments. Part II : Extension to gas mixture adsorption.


    Belmabkhout, Youssef; Frère, Marc; De Weireld, Guy


    Abstract In this paper, we present a rigorous statistical thermodynamic approach for the calculation of mixed gas adsorption equilibrium data on uniform surfaces. The non-ideality of both the mixed gas phase and adsorbed phase is considered by using the Redlich-Kwong EOS associated to the Lorentz-Berthelot mixing rules. This is an elegant way to extend the model presented in Part I and to predict multicomponent gas adsorption equilibria for highly non-ideal systems from parameters ...

  2. Influence of cation structure on binary liquid-liquid equilibria for systems containing ionic liquids based on trifluoromethanesulfonate anion with hydrocarbons. (United States)

    Marciniak, Andrzej; Karczemna, Ewa


    Binary liquid-liquid equilibria for 15 systems containing an ionic liquid (1-butyl-3-methylimidazolium trifluoromethanesulfonate, 1-butyl-3-methylpyridinium trifluoromethanesulfonate, 1-butyl-1-methylpyrrolidinium trifluoromethanesulfonate) with a hydrocarbon (n-hexane, n-heptane, cyclohexane, benzene, toluene) were measured by the dynamic method. The influence of cation structure of trifluoromethanesulfonate anion based ionic liquids on solubility of aliphatic and aromatic hydrocarbons is discussed.

  3. 13C and 1H NMR of 2,6-diaryl-1-hydroxy piperidin-4-one oximes; substituent effects on cis/trans ratio and conformational equilibria. (United States)

    Díaz, E; Barrios, H; del Río Portilla, F; Guzmán, A; Aguilera, J L; Becerril, R; Jankowski, C K; Reynolds, W F


    The reaction of substituted diarylidene acetones with hydroxylamine hydrochloride affords isomeric N-hydroxy diaryl piperidinone oximes as main products. The structures as well as conformational equilibria of these products were established by 1H and 13C NMR spectroscopy and further studied by variable temperature NMR. It was found that the cis/trans ratio of 2,6-substituted piperidine derivatives depended on the position of the substituent on the aromatic ring.

  4. Dynamic changes in temperature extremes and their association with atmospheric circulation patterns in the Songhua River Basin, China (United States)

    Zhong, Keyuan; Zheng, Fenli; Wu, Hongyan; Qin, Chao; Xu, Ximeng


    Understanding dynamic changes in climate extremes is important in forecasting extreme climate events and reducing their associated impacts. The objectives of this study were to analyze the spatiotemporal variations in temperature extremes and their association with atmospheric circulation, based on daily maximum (TX) and minimum temperatures (TN) collected from 60 meteorological stations in the Songhua River Basin (SRB) and its surroundings from 1960 to 2014. Following the ETCCDI (Expert Team on Climate Change Detection and Indices), eight extreme temperature indices, including three warm indices, three cold indices and two extreme indices, were chosen to quantify temperature extremes. The Mann-Kendall method and linear trend analysis were used to examine the trends, and Pearson correlation analysis was used to analyze the correlation between the temperature extremes and each atmospheric circulation. The results showed that warm indices, including the number of warm nights, warm days, and summer days, and extreme indices, including minimum TN and maximum TX, showed increasing trends in the SRB from 1960 to 2014. On the other hand, cold indices, including the number of cold nights, cold days and frost days, showed decreasing trends; Warm indices and maximum TX showed significant positive correlations with latitude (P < 0.01). The Arctic Oscillation index (AO) displayed significant negative correlations with the cold indices (P < 0.01) and positive correlations with the warm indices. The warm indices and extreme indices had positive correlations with the Northern Hemisphere Subtropical High area and intensity indices, while the reverse relationship was found between the cold indices and Northern Hemisphere Subtropical High. The Asia polar vortex area and intensity indices showed negative correlations with warm indices and extreme indices, while they were positively correlated to cold indices. The multivariate ENSO index (MEI) showed no linear correlation with any of

  5. Extreme Conditions Modeling Workshop Report

    Energy Technology Data Exchange (ETDEWEB)

    Coe, R. G.; Neary, V. S.; Lawson, M. J.; Yu, Y.; Weber, J.


    Sandia National Laboratories (SNL) and the National Renewable Energy Laboratory (NREL) hosted the Wave Energy Converter (WEC) Extreme Conditions Modeling (ECM) Workshop in Albuquerque, NM on May 13th-14th, 2014. The objective of the workshop was to review the current state of knowledge on how to model WECs in extreme conditions (e.g. hurricanes and other large storms) and to suggest how U.S. Department of Energy (DOE) and national laboratory resources could be used to improve ECM methods for the benefit of the wave energy industry.

  6. Automation Rover for Extreme Environments (United States)

    Sauder, Jonathan; Hilgemann, Evan; Johnson, Michael; Parness, Aaron; Hall, Jeffrey; Kawata, Jessie; Stack, Kathryn


    Almost 2,300 years ago the ancient Greeks built the Antikythera automaton. This purely mechanical computer accurately predicted past and future astronomical events long before electronics existed1. Automata have been credibly used for hundreds of years as computers, art pieces, and clocks. However, in the past several decades automata have become less popular as the capabilities of electronics increased, leaving them an unexplored solution for robotic spacecraft. The Automaton Rover for Extreme Environments (AREE) proposes an exciting paradigm shift from electronics to a fully mechanical system, enabling longitudinal exploration of the most extreme environments within the solar system.

  7. Modelling conditional correlations of asset returns: A smooth transition approach

    DEFF Research Database (Denmark)

    Silvennoinen, Annastiina; Teräsvirta, Timo

    In this paper we propose a new multivariate GARCH model with time-varying conditional correlation structure. The time-varying conditional correlations change smoothly between two extreme states of constant correlations according to a predetermined or exogenous transition variable. An LM-test is d......In this paper we propose a new multivariate GARCH model with time-varying conditional correlation structure. The time-varying conditional correlations change smoothly between two extreme states of constant correlations according to a predetermined or exogenous transition variable. An LM...

  8. Potentiometric investigations of molecular heteroconjugation equilibria of substituted phenol+n-butylamine systems in dimethyl sulfoxide

    Energy Technology Data Exchange (ETDEWEB)

    Czaja, MaIgorzata [Department of General Chemistry, University of Gdansk, Sobieskiego 18, 80-952 Gdansk (Poland); Baginska, Katarzyna [Department of General Chemistry, University of Gdansk, Sobieskiego 18, 80-952 Gdansk (Poland); Kozak, Anna [Department of General Chemistry, University of Gdansk, Sobieskiego 18, 80-952 Gdansk (Poland); Makowski, Mariusz [Department of General Chemistry, University of Gdansk, Sobieskiego 18, 80-952 Gdansk (Poland); Chmurzynski, Lech [Department of General Chemistry, University of Gdansk, Sobieskiego 18, 80-952 Gdansk (Poland)]. E-mail:


    Molecular heteroconjugation constants, K{sub BHA}{sup DMSO} and K{sub AHB}{sup DMSO}, expressed as their logarithms, have been determined by potentiometric titration for eleven substituted phenol+n-butylamine systems in a polar protophilic aprotic solvent, dimethyl sulfoxide (DMSO). An increasing tendency towards molecular heteroconjugation in these systems without proton transfer has been found with increasing pK{sub a}{sup DMSO} (HA), i.e., with decreasing phenol acidity. Moreover, a linear correlation has been established between the determined lgK{sub BHA}{sup DMSO} values and pK{sub a}{sup DMSO} (HA). Furthermore, overall stability constants, lgK{sub o}{sup DMSO}, could be correlated linearly with pK{sub a}{sup DMSO} (HA) values.

  9. Isobaric vapor-liquid equilibria for methanol + ethanol + water and the three constituent binary systems

    Energy Technology Data Exchange (ETDEWEB)

    Kurihara, Kiyofumi; Nakamichi, Mikiyoshi; Kojima, Kazuo (Nihon Univ., Tokyo (Japan). Dept. of Industrial Chemistry)


    Vapor-liquid equilibrium data for methanol + ethanol + water and its three constituent binary systems methanol + ethanol, ethanol + water, and methanol + water were measured at 101.3 kPa using a liquid-vapor ebullition-type equilibrium still. The experimental binary data were correlated by the NRTL equation. The ternary system methanol + ethanol + water was predicted by means of the binary NRTL parameters with good accuracy.

  10. Extreme river flow dependence in Northern Scotland (United States)

    Villoria, M. Franco; Scott, M.; Hoey, T.; Fischbacher-Smith, D.


    Various methods for the spatial analysis of hydrologic data have been developed recently. Here we present results using the conditional probability approach proposed by Keef et al. [Appl. Stat. (2009): 58,601-18] to investigate spatial interdependence in extreme river flows in Scotland. This approach does not require the specification of a correlation function, being mostly suitable for relatively small geographical areas. The work is motivated by the Flood Risk Management Act (Scotland (2009)) which requires maps of flood risk that take account of spatial dependence in extreme river flow. The method is based on two conditional measures of spatial flood risk: firstly the conditional probability PC(p) that a set of sites Y = (Y 1,...,Y d) within a region C of interest exceed a flow threshold Qp at time t (or any lag of t), given that in the specified conditioning site X > Qp; and, secondly the expected number of sites within C that will exceed a flow Qp on average (given that X > Qp). The conditional probabilities are estimated using the conditional distribution of Y |X = x (for large x), which can be modeled using a semi-parametric approach (Heffernan and Tawn [Roy. Statist. Soc. Ser. B (2004): 66,497-546]). Once the model is fitted, pseudo-samples can be generated to estimate functionals of the joint tails of the distribution of (Y,X). Conditional return level plots were directly compared to traditional return level plots thus improving our understanding of the dependence structure of extreme river flow events. Confidence intervals were calculated using block bootstrapping methods (100 replicates). We report results from applying this approach to a set of four rivers (Dulnain, Lossie, Ewe and Ness) in Northern Scotland. These sites were chosen based on data quality, spatial location and catchment characteristics. The river Ness, being the largest (catchment size 1839.1km2) was chosen as the conditioning river. Both the Ewe (441.1km2) and Ness catchments have

  11. Extreme Energy Events Monitoring report

    CERN Document Server

    Baimukhamedova, Nigina


    Following paper reflects the progress I made on Summer Student Program within Extreme Energy Events Monitor project I was working on. During 8 week period I managed to build a simple detector system that is capable of triggering events similar to explosions (sudden change in sound levels) and measuring approximate location of the event. Source codes are available upon request and settings described further.

  12. Astrobiology: Life in Extreme Environments (United States)

    Kaur, Preeti


    Astrobiology is the study of the origin, evolution and distribution of life in the universe. It seeks to answer two important scientific questions: how did we get here and are we alone in the universe? Scientists begin by studying life on Earth and its limits. The discovery of extremophiles on Earth capable of surviving extremes encourages the…

  13. Applied extreme-value statistics

    Energy Technology Data Exchange (ETDEWEB)

    Kinnison, R.R.


    The statistical theory of extreme values is a well established part of theoretical statistics. Unfortunately, it is seldom part of applied statistics and is infrequently a part of statistical curricula except in advanced studies programs. This has resulted in the impression that it is difficult to understand and not of practical value. In recent environmental and pollution literature, several short articles have appeared with the purpose of documenting all that is necessary for the practical application of extreme value theory to field problems (for example, Roberts, 1979). These articles are so concise that only a statistician can recognise all the subtleties and assumptions necessary for the correct use of the material presented. The intent of this text is to expand upon several recent articles, and to provide the necessary statistical background so that the non-statistician scientist can recognize and extreme value problem when it occurs in his work, be confident in handling simple extreme value problems himself, and know when the problem is statistically beyond his capabilities and requires consultation.

  14. Extreme conditions (p, T, H)

    Energy Technology Data Exchange (ETDEWEB)

    Mesot, J. [Lab. for Neutron Scattering ETH Zurich, Zurich (Switzerland) and Paul Scherrer Institute, Villigen (Switzerland)


    The aim of this paper is to summarize the sample environment which will be accessible at the SINQ. In order to illustrate the type of experiments which will be feasible under extreme conditions of temperature, magnetic field and pressure at the SINQ a few selected examples are also given. (author) 7 figs., 14 refs.

  15. REVIEW ARTICLE Tokamak equilibria with nearly zero central current: the current hole (United States)

    Fujita, Takaaki


    The observation of stable sustainment of the 'current hole', namely the nearly zero current density region in the central part of a tokamak plasma, has opened a new class of configurations in tokamak plasmas, and a variety of research from the viewpoints of equilibrium, magnetohydrodynamics (MHD) stability, particle orbits and radial transport has been generated. Some theories and codes have been tested and extended by being applied to extreme conditions in the current hole with very weak poloidal field. The current hole is generated due to a transient negative toroidal electric field established when a large off-axis non-inductive current is rapidly formed. It has been observed in high confinement plasmas with a large fraction of bootstrap current in advanced tokamak operation. The current hole is very stiff against current drive, which suggests that it is a saturated or self-organized system. Appearance of the current hole in ITER and DEMO would be expected in some of the operation scenarios, and its influence and its control methods have been studied. Results of experimental and theoretical studies on the current hole are reviewed.

  16. Extremal higher spin black holes

    Energy Technology Data Exchange (ETDEWEB)

    Bañados, Máximo [Instituto de Física, Pontificia Universidad Católica de Chile, Casilla 306, Santiago (Chile); Castro, Alejandra [Institute for Theoretical Physics, University of Amsterdam,Science Park 904, Postbus 94485, Amsterdam, 1090 GL (Netherlands); Faraggi, Alberto [Instituto de Física, Pontificia Universidad Católica de Chile, Casilla 306, Santiago (Chile); Jottar, Juan I. [Institut für Theoretische Physik, ETH Zürich,Zürich, CH-8093 (Switzerland)


    The gauge sector of three-dimensional higher spin gravities can be formulated as a Chern-Simons theory. In this context, a higher spin black hole corresponds to a flat connection with suitable holonomy (smoothness) conditions which are consistent with the properties of a generalized thermal ensemble. Building on these ideas, we discuss a definition of black hole extremality which is appropriate to the topological character of 3d higher spin theories. Our definition can be phrased in terms of the Jordan class of the holonomy around a non-contractible (angular) cycle, and we show that it is compatible with the zero-temperature limit of smooth black hole solutions. While this notion of extremality does not require supersymmetry, we exemplify its consequences in the context of sl(3|2)⊕sl(3|2) Chern-Simons theory and show that, as usual, not all extremal solutions preserve supersymmetries. Remarkably, we find in addition that the higher spin setup allows for non-extremal supersymmetric black hole solutions. Furthermore, we discuss our results from the perspective of the holographic duality between sl(3|2)⊕sl(3|2) Chern-Simons theory and two-dimensional CFTs with W{sub (3|2)} symmetry, the simplest higher spin extension of the N=2 super-Virasoro algebra. In particular, we compute W{sub (3|2)} BPS bounds at the full quantum level, and relate their semiclassical limit to extremal black hole or conical defect solutions in the 3d bulk. Along the way, we discuss the role of the spectral flow automorphism and provide a conjecture for the form of the semiclassical BPS bounds in general N=2 two-dimensional CFTs with extended symmetry algebras.

  17. Correlation spectrometer (United States)

    Sinclair, Michael B [Albuquerque, NM; Pfeifer, Kent B [Los Lunas, NM; Flemming, Jeb H [Albuquerque, NM; Jones, Gary D [Tijeras, NM; Tigges, Chris P [Albuquerque, NM


    A correlation spectrometer can detect a large number of gaseous compounds, or chemical species, with a species-specific mask wheel. In this mode, the spectrometer is optimized for the direct measurement of individual target compounds. Additionally, the spectrometer can measure the transmission spectrum from a given sample of gas. In this mode, infrared light is passed through a gas sample and the infrared transmission signature of the gasses present is recorded and measured using Hadamard encoding techniques. The spectrometer can detect the transmission or emission spectra in any system where multiple species are present in a generally known volume.

  18. Correlative microscopy. (United States)

    Loussert Fonta, Céline; Humbel, Bruno M


    In recent years correlative microscopy, combining the power and advantages of different imaging system, e.g., light, electrons, X-ray, NMR, etc., has become an important tool for biomedical research. Among all the possible combinations of techniques, light and electron microscopy, have made an especially big step forward and are being implemented in more and more research labs. Electron microscopy profits from the high spatial resolution, the direct recognition of the cellular ultrastructure and identification of the organelles. It, however, has two severe limitations: the restricted field of view and the fact that no live imaging can be done. On the other hand light microscopy has the advantage of live imaging, following a fluorescently tagged molecule in real time and at lower magnifications the large field of view facilitates the identification and location of sparse individual cells in a large context, e.g., tissue. The combination of these two imaging techniques appears to be a valuable approach to dissect biological events at a submicrometer level. Light microscopy can be used to follow a labelled protein of interest, or a visible organelle such as mitochondria, in time, then the sample is fixed and the exactly same region is investigated by electron microscopy. The time resolution is dependent on the speed of penetration and fixation when chemical fixatives are used and on the reaction time of the operator for cryo-fixation. Light microscopy can also be used to identify cells of interest, e.g., a special cell type in tissue or cells that have been modified by either transfections or RNAi, in a large population of non-modified cells. A further application is to find fluorescence labels in cells on a large section to reduce searching time in the electron microscope. Multiple fluorescence labelling of a series of sections can be correlated with the ultrastructure of the individual sections to get 3D information of the distribution of the marked proteins: array

  19. Behavioral and life history responses to extreme climatic conditions: Studies on a migratory songbird

    Directory of Open Access Journals (Sweden)

    A. P. Møller


    Full Text Available Behavioral responses to environmental change are the mechanisms that allow for rapid phenotypic change preventing temporary or permanent damage and hence preventing reductions in fitness. Extreme climatic events are by definition rare, although they are predicted to increase in amplitude and frequency in the coming years. However, our current knowledge about behavioral responses to such extreme events is scarce. Here I analyze two examples of the effects of extreme weather events on behavior and life history: (1 A comparison of behavior and life history during extremely warm and extremely cold years relative to normal years; and (2 a comparison of behavior before and after the extremely early snowfall in fall 1974 when numerous birds died in the Alps during September-October. Behavioral and life history responses of barn swallows Hirundo rustica to extremely cold and extremely warm years were positively correlated, with particularly large effect sizes in cold years. Extreme mortality in barn swallows during fall migration 1974 in the Alps eliminated more than 40% of the breeding population across large areas in Central and Northern Europe, and this affected first arrival date, changes in timing and extent of reproduction and changes in degree of breeding sociality supposedly as a consequence of correlated responses to selection. Finally, I provide directions for research that will allow us to better understand behavior and life history changes in response to extreme climate change [Current Zoology 57 (3: 351–362, 2011].

  20. Grand canonical Monte Carlo simulations of vapor-liquid equilibria using a bias potential from an analytic equation of state. (United States)

    Castillo Sanchez, Juan Manuel; Danner, Timo; Gross, Joachim


    This article introduces an efficient technique for the calculation of vapor-liquid equilibria of fluids. Umbrella Sampling Monte Carlo simulations in the grand canonical ensemble were conducted for various types of molecules. In Umbrella Sampling, a weight function is used for allowing the simulation to reach unlikely states in the phase space. In the present case this weight function, that allows the system to overcome the energetic barrier between a vapor and liquid phase, was determined by a trivialized Density Functional Theory (DFT) using the PC-SAFT equation of state. The implementation presented here makes use of a multicanonical ensemble approach to divide the space of fluctuating particle number N into various subsystems. The a priori estimate of the weight function from the analytic DFT allows the parallelization of the calculation, which significantly reduces the computation time. In addition, it is shown that the analytic equation of state can be used to substitute sampling the dense liquid phase, where the sampling of insertion and deletion moves become demanding.

  1. Implications of climate variability for the detection of multiple equilibria and for rapid transitions in the atmosphere-vegetation system

    Energy Technology Data Exchange (ETDEWEB)

    Bathiany, S. [Max Planck Institute for Meteorology, Hamburg (Germany); Claussen, M. [Max Planck Institute for Meteorology, Hamburg (Germany); Universitaet Hamburg, Meteorologisches Institut, Hamburg (Germany); Fraedrich, K. [Universitaet Hamburg, Meteorologisches Institut, Hamburg (Germany)


    Paleoclimatic records indicate a decline of vegetation cover in the Western Sahara at the end of the African Humid Period (about 5,500 years before present). Modelling studies have shown that this phenomenon may be interpreted as a critical transition that results from a bifurcation in the atmosphere-vegetation system. However, the stability properties of this system are closely linked to climate variability and depend on the climate model and the methods of analysis. By coupling the Planet Simulator (PlaSim), an atmosphere model of intermediate complexity, with the simple dynamic vegetation model VECODE, we assess previous methods for the detection of multiple equilibria, and demonstrate their limitations. In particular, a stability diagram can yield misleading results because of spatial interactions, and the system's steady state and its dependency on initial conditions are affected by atmospheric variability and nonlinearities. In addition, we analyse the implications of climate variability for the abruptness of a vegetation decline. We find that a vegetation collapse can happen at different locations at different times. These collapses are possible despite large and uncorrelated climate variability. Because of the nonlinear relation between vegetation dynamics and precipitation the green state is initially stabilised by the high variability. When precipitation falls below a critical threshold, the desert state is stabilised as variability is then also decreased. (orig.)

  2. Kinetics, equilibria, and modeling of the formation of oligosaccharides from D-glucose with Aspergillus niger glucoamylases I and II. (United States)

    Nikolov, Z L; Meagher, M M; Reilly, P J


    Near-homogeneous forms of glucoamylases I and II, previously purified from an industrial Aspergillus niger preparation, were incubated with D-glucose at a number of temperatures and pH values. Kinetics and equilibria of the formation of alpha,beta-trehalose, kojibiose, nigerose, maltose, isomaltose, panose, and isomaltotriose, which with isomaltotetraose were the only products formed, were determined. There was no difference in the abilities of GA I and GA II to form these products. Activation energies for the formation of maltose and panose were lower than those of the other Oligosaccharides. Relative rates of oligosaccharide production based on glucoamylase hydrolytic activity did not vary significantly between pH 3.5 and 4.5 but were lower at pH 5.5. Maltose was formed much faster than any other product. Equilibrium concentrations at higher dissolved solids concentrations decreased in the order isomaltose, isomaltotriose, kojibiose, nigerose, maltose, alpha, beta-Mrehalose, panose, and isomaltotetraose. They were not appreciably affected by changes in temperature or pH. A kinetic model based on adsorption of D-glucose and the seven di- and trisaccharides by the first three glucoamylase subsites was formulated. Oligosaccharide formation was simulated with the model, using equilibrium data gathered for this article and subsite binding energies and kinetic parameters for oligosaccharide hydrolysis measured earlier. Agreement of simulated and actual oligosaccharide formation data through the course of the reaction was excellent except at very high solid concentrations.

  3. Interatomic Lennard-Jones potentials of linear and branched alkanes calibrated by Gibbs ensemble simulations for vapor-liquid equilibria (United States)

    Chang, Jaeeon; Sandler, Stanley I.


    We propose Lennard-Jones potential parameters for interatomic interactions of linear and branched alkanes based on matching the results of Gibbs ensemble simulations of vapor-liquid equilibria to experimental data. The alkane model is similar as in the OPLS-AA [W. L. Jorgensen, D. S. Maxwell, and J. Tirado-Rives, J. Am. Chem. Soc. 118, 11225 (1996)], but multiple atom types for carbon based on the number of covalently bonded hydrogen atoms are necessary to accurately reproduce liquid densities and enthalpies of vaporization with the errors of 2.1% and 3.3%, respectively, for hydrocarbons of various chain lengths and structures. We find that the attraction energies of the carbon atoms are almost proportional to the number of covalent hydrogen atoms with each increasing the carbon energy parameter by ≈0.033 kcal/mol. Though the present force field outperforms the OPLS-AA force field for alkanes we studied, systematic deviations for vapor pressures are still observed with errors of 15%-30%, and critical temperatures are slightly underestimated. We think that these shortcomings are probably due to the inadequacy of the two-parameter Lennard-Jones potential, and especially its behavior at short distances.

  4. Applications of the SW96 formulation in the thermodynamic calculation of fluid inclusions and mineral-fluid equilibria

    Directory of Open Access Journals (Sweden)

    Jia Zhang


    Full Text Available The SW96 formulation explicit in Helmholtz free energy proposed by Span and Wagner (1996 is the most accurate multifunction equation of state of CO2 fluid, from which all thermodynamic properties can be obtained over a wide temperature-pressure range from 216.592 to 1100 K and from 0 to 8000 bar with or close to experimental accuracy. This paper reports the applications of the SW96 formulation in fluid inclusions and mineral-fluid equilibria. A reliable and highly efficient algorithm is presented for the saturated properties of CO2 so that the formulation can be conveniently applied in the study of fluid inclusions, such as calculation of homogenization pressures, homogenization densities (or molar volumes, volume fractions of vapor phase and isochores. Meanwhile, the univariant curves of some typical decarbonation reactions of minerals are calculated with the SW96 formulation and relevant thermodynamic models of minerals. The computer code of the SW96 formulation can be obtained from the corresponding author.

  5. Benzimidazole acrylonitriles as multifunctional push-pull chromophores: Spectral characterisation, protonation equilibria and nanoaggregation in aqueous solutions (United States)

    Horak, Ema; Vianello, Robert; Hranjec, Marijana; Krištafor, Svjetlana; Zamola, Grace Karminski; Steinberg, Ivana Murković


    Heterocyclic donor-π-acceptor molecular systems based on an N,N-dimethylamino phenylacrylonitrile benzimidazole skeleton have been characterised and are proposed for potential use in sensing applications. The benzimidazole moiety introduces a broad spectrum of useful multifunctional properties to the system including electron accepting ability, pH sensitivity and compatibility with biomolecules. The photophysical characterisation of the prototropic forms of these chromophores has been carried out in both solution and on immobilisation in polymer films. The experimental results are further supported by computational determination of pKa values. It is noticed that compound 3 forms nanoaggregates in aqueous solutions with aggregation-induced emission (AIE) at 600 nm. All the systems demonstrate spectral pH sensitivity in acidic media which shifts towards near-neutral values upon immobilisation in polymer films or upon aggregation in an aqueous environment (compound 3). The structure-property relationships of these functional chromophores, involving their spectral characteristics, acid-base equilibria, pKa values and aggregation effects have been determined. Potential applications of the molecules as pH and biomolecular sensors are proposed based on their pH sensitivity and AIE properties.

  6. The thermodynamic properties of solutions and phase equilibria in the water-2-butanol-sodium chloride system (United States)

    Veryaeva, E. S.; Bogachev, A. G.; Shishin, D. I.; Voskov, A. L.; Igumnov, S. N.; Mamontov, M. N.; Uspenskaya, I. A.


    Fragments of the phase diagram of the H2O-2-C4H9OH-NaCl system were studied experimentally at 298 and 313 K. The thermodynamic properties of sodium chloride in three-component solutions with ionic strengths up to 1.9 mol/kg and alcohol content in the solvent 4.97 and 10 wt % were measured at 298 and 323 K by the electromotive force method with ion-selective electrodes. The eNRTL (electrolyte Non-Random Two-Liquids) model parameters correctly describing the results of electrochemical measurements of the partial properties of NaCl and phase equilibria in the water-2-butanol-sodium chloride ternary system and binary subsystems constituting it were determined. The isothermal sections of the phase diagram of the H2O-2-C4H9OH-NaCl system were calculated using the method of convex hulls implemented in the TernAPI package.

  7. Acid-base equilibria of 2,4-diiodo-6-methylphenylcarbamoylmethyl iminodiacetic acid and its labeling with technetium-99m

    Directory of Open Access Journals (Sweden)



    Full Text Available The acid-base equilibria of a novel hepatobiliary imaging agent, 2,4-diiodo-6-methylphenylcarbamoylmethyl iminodiacetic acid (DIIODIDA were studied. The potentiometrically determined acidity constants of the second carboxylic group, amino and amide groups were pK2 = 2.52 ± 0.02; pK3 = 5.86 ± 0.06 and pK4 = 10.9 ± 0.1. The determinations were performed at 25 ºC and an ionic strength of 0.1 mol/dm3 (NaCl. The acidity constants (pK1 = 1.3 ± 0.4 corresponding to the first carboxylic group was determined indirectly, on the basis of equilibrium constants obtained in a heterogeneous system, at 25 ºC and an ionic strength 1 mol/dm3 (HCl, NaCl. DIIODIDA was labeled with technetium-99m, and the influence of pH on the yield of labeling was investigated. It was found that labeling within the pH range from 5.5 to 6.5 provided a radiopharmaceutical of high radiochemical purity (>98 %.

  8. Equilibria and Free Vibration of a Two-Pulley Belt-Driven System with Belt Bending Stiffness

    Directory of Open Access Journals (Sweden)

    Jieyu Ding


    Full Text Available Nonlinear equilibrium curvatures and free vibration characteristics of a two-pulley belt-driven system with belt bending stiffness and a one-way clutch are investigated. With nonlinear dynamical tension, the transverse vibrations of the translating belt spans and the rotation motions of the pulleys and the accessory shaft are coupled. Therefore, nonlinear piecewise discrete-continuous governing equations are established. Considering the bending stiffness of the translating belt spans, the belt spans are modeled as axially moving beams. The pattern of equilibria is a nontrivial solution. Furthermore, the nontrivial equilibriums of the dynamical system are numerically determined by using two different approaches. The governing equations of the vibration near the equilibrium solutions are derived by introducing a coordinate transform. The natural frequencies of the dynamical systems are studied by using the Galerkin method with various truncations and the differential and integral quadrature methods. Moreover, the convergence of the Galerkin truncation is investigated. Numerical results reveal that the study needs 16 terms after truncation in order to determine the free vibration characteristics of the pulley-belt system with the belt bending stiffness. Furthermore, the first five natural frequencies are very sensitive to the bending stiffness of the translating belt.

  9. Liquid - liquid equilibria of the water + butyric acid + decanol ternary system

    Directory of Open Access Journals (Sweden)

    S.I. Kirbaslar


    Full Text Available Liquid-liquid equilibrium (LLE data for the water + butyric acid + decanol ternary system were determined experimentally at temperatures of 298.15, 308.15 and 318.15 K. Complete phase diagrams were obtained by determining the solubility curve and the tie lines. The reliability of the experimental tie line data was confirmed with the Othmer-Tobias correlation. The UNIFAC method was used to predict the phase equilibrium of the system using the interaction parameters for groups CH3, CH2, COOH, OH and H2O determined experimentally. Distribution coefficients and separation factors were evaluated for the immiscibility region.

  10. Multidecadal oscillations in rainfall and hydrological extremes


    Willems, Patrick


    Many studies have anticipated a worldwide increase in the frequency and intensity of precipitation extremes and floods since the last decade(s). Natural variability by climate oscillations partly determines the observed evolution of precipitation extremes. Based on a technique for the identification and analysis of changes in extreme quantiles, it is shown that hydrological extremes have oscillatory behaviour at multidecadal time scales. Results are based on nearly independent extremes extrac...

  11. Growth rates and variances of unexploited wolf populations in dynamic equilibria (United States)

    Mech, L. David; Fieberg, John


    Several states have begun harvesting gray wolves (Canis lupus), and these states and various European countries are closely monitoring their wolf populations. To provide appropriate perspective for determining unusual or extreme fluctuations in their managed wolf populations, we analyzed natural, long-term, wolf-population-density trajectories totaling 130 years of data from 3 areas: Isle Royale National Park in Lake Superior, Michigan, USA; the east-central Superior National Forest in northeastern Minnesota, USA; and Denali National Park, Alaska, USA. Ratios between minimum and maximum annual sizes for 2 mainland populations (n = 28 and 46 yr) varied from 2.5–2.8, whereas for Isle Royale (n = 56 yr), the ratio was 6.3. The interquartile range (25th percentile, 75th percentile) for annual growth rates, Nt+1/Nt, was (0.88, 1.14), (0.92, 1.11), and (0.86, 1.12) for Denali, Superior National Forest, and Isle Royale respectively. We fit a density-independent model and a Ricker model to each time series, and in both cases we considered the potential for observation error. Mean growth rates from the density-independent model were close to 0 for all 3 populations, with 95% credible intervals including 0. We view the estimated model parameters, including those describing annual variability or process variance, as providing useful summaries of the trajectories of these populations. The estimates of these natural wolf population parameters can serve as benchmarks for comparison with those of recovering wolf populations. Because our study populations were all from circumscribed areas, fluctuations in them represent fluctuations in densities (i.e., changes in numbers are not confounded by changes in occupied area as would be the case with populations expanding their range, as are wolf populations in many states).

  12. The influence of mindfulness on upper extremity illness. (United States)

    Voskuijl, Timothy; Ring, David


    Previous studies suggest a benefit of mindfulness-based interventions on pain conditions. This study addresses the null hypothesis that mindfulness is not correlated with pain intensity or magnitude of disability in orthopedic upper extremity conditions. In a prospective cohort, the correlation of the two separate aspects of mindfulness-acceptance and awareness-with disability and pain intensity was tested in patients with nonacute upper extremity conditions. Regression analyses were performed to determine factors associated with arm-specific disability and pain intensity. Awareness and acceptance both correlated with arm-specific disability, but only awareness was retained as a predictor in the best multivariable model. Neither awareness nor acceptance correlated with pain intensity. Pain interference and symptoms of depression accounted for more of the variation in disability and pain intensity. Improved mood and decreased pain interference (a greater sense that one can accomplish one's goals in spite of pain) may be more fruitful than increased mindfulness for patients with nonacute conditions of the upper extremity.

  13. Extreme Conditions Modeling Workshop Report

    Energy Technology Data Exchange (ETDEWEB)

    Coe, Ryan Geoffrey [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Neary, Vincent Sinclair [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Lawon, Michael J. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Yu, Yi-Hsiang [National Renewable Energy Lab. (NREL), Golden, CO (United States); Weber, Jochem [National Renewable Energy Lab. (NREL), Golden, CO (United States)


    Sandia National Laboratories (SNL) and the National Renewable Energy Laboratory (NREL) hosted the Wave Energy Converter (WEC) Extreme Conditions Modeling (ECM) Workshop in Albuquerque, New Mexico on May 13–14, 2014. The objective of the workshop was to review the current state of knowledge on how to numerically and experimentally model WECs in extreme conditions (e.g. large ocean storms) and to suggest how national laboratory resources could be used to improve ECM methods for the benefit of the wave energy industry. More than 30 U.S. and European WEC experts from industry, academia, and national research institutes attended the workshop, which consisted of presentations from W EC developers, invited keynote presentations from subject matter experts, breakout sessions, and a final plenary session .

  14. Extended UNIQUAC model for correlation and prediction of vapour-liquid-solid equilibria in aqueous salt systems containing non-electrolytes

    DEFF Research Database (Denmark)

    Iliuta, Maria C.; Thomsen, Kaj; Rasmussen, Peter


    to aqueous salt systems containing non-electrolytes in order to demonstrate its ability in representing solid-liquid-vapour (SLV) equilibrium and thermal property data for these strongly non-ideal systems. The model requires only pure component and binary temperature-dependent interaction parameters....... The calculations are based on an extensive database consisting of salt solubility data in pure and mixed solvents, VLE data for solvent mixtures and mixed solvent-electrolyte systems and thermal properties for mixed solvent solutions. Application of the model to the methanol-water system in the presence of several...... ions (Na+, K+, NH4+, Cl-, NO3-, SO42-, CO2- and HCO3-) shows that the Extended UNIQUAC model is able to give an accurate description of VLE and SLE in ternary add quaternary mixtures, using the name set of binary interaction parameters. The capability of the model to predict accurately the phase...

  15. Large Extremity Peripheral Nerve Repair (United States)


    axons, the effects of which worsen with time.5 Following trauma , priority is given to patient stabilization and wound decontamination before the onset...STATEMENT Approved for Public Release; Distribution Unlimited 13. SUPPLEMENTARY NOTES 14. ABSTRACT In current war trauma , 20-30% of all extremity...wrap/ fixation method to be sutureless photochemical tissue bonding with the crosslinked amnion wrap. Autograft is often unavailable in wounded

  16. Thermodynamic optimization and phase equilibria in the ternary system Ni–Sn–Zn

    Energy Technology Data Exchange (ETDEWEB)

    Gandova, V., E-mail: [University of Food Technologies, Inorganic and Physical Chemistry Department, 26 Mariza avenue, 4000 Plovdiv (Bulgaria); Vassilev, G.P. [University of Plovdiv, Faculty of Chemistry, 24 Tsar Asen str., 4000 Plovdiv (Bulgaria)


    Highlights: • Thermodynamic description of the Ni–Sn–Zn system was obtained. • Six isothermal sections were calculated. • Third constituents solubility in binary phases’ extensions were taken into account. • Good correlation between calculated and experimental data was obtained. - Abstract: Recent experimental results obtained by differential scanning calorimetry, Scanning Electron Microscopy and other methods were used to develop a thermodynamic description of the ternary system Ni–Sn–Zn. Four ternary non-stoichiometric compounds (T1–T4), mentioned in the literature, were described using three-sublattice models. Previously known optimizations of the binary subsystems were remodeled to comply with the new experimental data. The solubility of the respective ternary components, i.e., Zn in Ni–Sn phases and Sn in Ni–Zn phases, were taken into account and optimized ternary parameters were derived. Six isothermal sections were calculated using Thermo-Calc software.

  17. Moderate and extreme maternal obesity.

    LENUS (Irish Health Repository)

    Abdelmaboud, M O


    The aim of this study was to investigate the prevalence of moderate and extreme obesity among an Irish obstetric population over a 10-year period, and to evaluate the obstetric features of such pregnancies. Of 31,869 women delivered during the years 2000-2009, there were 306 women in the study group, including 173 in the moderate or Class 2 obese category (BMI 35-39.9) and 133 in the extreme or Class 3 obese category (BMI > or = 40).The prevalence of obese women with BMI > or = 35 was 9.6 per 1000 (0.96%), with an upward trend observed from 2.1 per 1000 in the year 2000, to 11.8 per 1000 in the year 2009 (P = 0.001). There was an increase in emergency caesarean section (EMCS) risk for primigravida versus multigravid women, within both obese categories (P < 0.001). However, there was no significant difference in EMCS rates observed between Class 2 and Class 3 obese women, when matched for parity. The prevalence of moderate and extreme obesity reported in this population is high, and appears to be increasing. The increased rates of abdominal delivery, and the levels of associated morbidity observed, have serious implications for such women embarking on pregnancy.

  18. Technology improves upper extremity rehabilitation. (United States)

    Kowalczewski, Jan; Prochazka, Arthur


    Stroke survivors with hemiparesis and spinal cord injury (SCI) survivors with tetraplegia find it difficult or impossible to perform many activities of daily life. There is growing evidence that intensive exercise therapy, especially when supplemented with functional electrical stimulation (FES), can improve upper extremity function, but delivering the treatment can be costly, particularly after recipients leave rehabilitation facilities. Recently, there has been a growing level of interest among researchers and healthcare policymakers to deliver upper extremity treatments to people in their homes using in-home teletherapy (IHT). The few studies that have been carried out so far have encountered a variety of logistical and technical problems, not least the difficulty of conducting properly controlled and blinded protocols that satisfy the requirements of high-level evidence-based research. In most cases, the equipment and communications technology were not designed for individuals with upper extremity disability. It is clear that exercise therapy combined with interventions such as FES, supervised over the Internet, will soon be adopted worldwide in one form or another. Therefore it is timely that researchers, clinicians, and healthcare planners interested in assessing IHT be aware of the pros and cons of the new technology and the factors involved in designing appropriate studies of it. It is crucial to understand the technical barriers, the role of telesupervisors, the motor improvements that participants can reasonably expect and the process of optimizing IHT-exercise therapy protocols to maximize the benefits of the emerging technology. Copyright © 2011 Elsevier B.V. All rights reserved.

  19. Lower Extremity Abnormalities in Children. (United States)

    Rerucha, Caitlyn M; Dickison, Caleb; Baird, Drew C


    Leg and foot problems in childhood are common causes of parental concern. Rotational problems include intoeing and out-toeing. Intoeing is most common in infants and young children. Intoeing is caused by metatarsus adductus, internal tibial torsion, and femoral anteversion. Out-toeing is less common than intoeing and occurs more often in older children. Out-toeing is caused by external tibial torsion and femoral retroversion. Angular problems include genu varum (bowleg) and genu valgum (knock knee). With pes planus (flatfoot), the arch of the foot is usually flexible rather than rigid. A history and physical examination that include torsional profile tests and angular measurements are usually sufficient to evaluate patients with lower extremity abnormalities. Most children who present with lower extremity problems have normal rotational and angular findings (i.e., within two standard deviations of the mean). Lower extremity abnormalities that are within normal measurements resolve spontaneously as the child grows. Radiologic studies are not routinely required, except to exclude pathologic conditions. Orthotics are not beneficial. Orthopedic referral is often not necessary. Rarely, surgery is required in patients older than eight years who have severe deformities that cause dysfunction.

  20. Extreme weather events and global crop production (United States)

    Ray, D. K.; Gerber, J. S.; West, P. C.


    Extreme weather events can lead to significant loss in crop production and even trigger global price spikes. However it is still not clear where exactly and what types of extreme events have resulted in sharp declines in crop production. Neither is it clear how frequently such extreme events have resulted in extreme crop production losses. Using extreme event metrics with a newly developed high resolution and long time series of crop statistics database we identify the frequency and type of extreme event driven crop production losses globally at high resolutions. In this presentation we will present our results as global maps identifying the frequency and type of extreme weather events that resulted in extreme crop production losses and quantify the losses. Understanding how extreme events affects crop production is critical for managing risk in the global food system

  1. Attosecond correlation dynamics (United States)

    Ossiander, M.; Siegrist, F.; Shirvanyan, V.; Pazourek, R.; Sommer, A.; Latka, T.; Guggenmos, A.; Nagele, S.; Feist, J.; Burgdörfer, J.; Kienberger, R.; Schultze, M.


    Photoemission of an electron is commonly treated as a one-particle phenomenon. With attosecond streaking spectroscopy we observe the breakdown of this single active-electron approximation by recording up to six attoseconds retardation of the dislodged photoelectron due to electronic correlations. We recorded the photon-energy-dependent emission timing of electrons, released from the helium ground state by an extreme-ultraviolet photon, either leaving the ion in its ground state or exciting it into a shake-up state. We identify an optical field-driven d.c. Stark shift of charge-asymmetric ionic states formed after the entangled photoemission as a key contribution to the observed correlation time shift. These findings enable a complete wavepacket reconstruction and are universal for all polarized initial and final states. Sub-attosecond agreement with quantum mechanical ab initio modelling allows us to determine the absolute zero of time in the photoelectric effect to a precision better than 1/25th of the atomic unit of time.

  2. Lymphatic Filariasis Disseminating to the Upper Extremity

    Directory of Open Access Journals (Sweden)

    Catherine Maldjian


    Full Text Available Lymphatic filariasis is the most common cause of acquired lymphedema worldwide (Szuba and Rockson, 1998. It is endemic to tropical and subtropical regions, and its effects are devastating. With over 100 million infected persons, it ranks second only to leprosy as the leading cause of permanent and long-term disability. Wuchereria bancrofti is the etiologic agent in 90% of cases. There is a dearth of published MRI findings with pathologically proven active infections, making this entity even more of a diagnostic dilemma. Imaging may provide the first clue that one is dealing with a parasite and may facilitate proper treatment and containment of this disease. This is the first report of pathologic correlation with MRI findings in the extremity in active filariasis. The magnetic resonance images demonstrate an enhancing, infiltrative, mass-like appearance with partial encasement of vasculature that has not been previously described in filariasis. Low signal strands in T2-hyperintense dilated lymphatic channels are seen and may depict live adult worms. We hypothesize that the low signal strands correspond to the collagen rich acellular cuticle. This, in combination with the surrounding hyperintense T2 signal, corresponding to a dilated lymphatic channel, may provide more specific MRI findings for active nematodal infection, which can prompt early biopsy, pathological correlation, and diagnosis.

  3. Correlation functions of Coulomb branch operators

    Energy Technology Data Exchange (ETDEWEB)

    Gerchkovitz, Efrat [Weizmann Institute of Science,Rehovot 76100 (Israel); Gomis, Jaume [Perimeter Institute for Theoretical Physics,Waterloo, ON N2L 2Y5 (Canada); Ishtiaque, Nafiz [Perimeter Institute for Theoretical Physics,Waterloo, ON N2L 2Y5 (Canada); Department of Physics, University of Waterloo,Waterloo, ON N2L 3G1 (Canada); Karasik, Avner; Komargodski, Zohar [Weizmann Institute of Science,Rehovot 76100 (Israel); Pufu, Silviu S. [Joseph Henry Laboratories, Princeton University,Princeton, NJ 08544 (United States)


    We consider the correlation functions of Coulomb branch operators in four-dimensional N=2 Superconformal Field Theories (SCFTs) involving exactly one anti-chiral operator. These extremal correlators are the “minimal' non-holomorphic local observables in the theory. We show that they can be expressed in terms of certain determinants of derivatives of the four-sphere partition function of an appropriate deformation of the SCFT. This relation between the extremal correlators and the deformed four-sphere partition function is non-trivial due to the presence of conformal anomalies, which lead to operator mixing on the sphere. Evaluating the deformed four-sphere partition function using supersymmetric localization, we compute the extremal correlators explicitly in many interesting examples. Additionally, the representation of the extremal correlators mentioned above leads to a system of integrable differential equations. We compare our exact results with previous perturbative computations and with the four-dimensional tt{sup ∗} equations. We also use our results to study some of the asymptotic properties of the perturbative series expansions we obtain in N=2 SQCD.

  4. Temperature extremes in Western Europe and associated atmospheric anomalies (United States)

    Carvalho, V. A.; Santos, J. A.


    This worḱs focal point is the analysis of temperature extremes over Western Europe in the period 1957-2007 and their relationship to large-scale anomalies in the atmospheric circulation patterns. The study is based on temperature daily time series recorded at a set of meteorological stations covering the target area. The large-scale anomalies are analyzed using data from the National Centers for Environmental Prediction reanalysis project. Firstly, a preliminary statistical analysis was undertaken in order to identify data gaps and erroneous values and to check the homogeneity of the time series, using not only elementary statistical approaches (e.g., chronograms, box-plots, scatter-plots), but also a set of non-parametric statistical tests particularly suitable for the analysis of monthly and seasonal mean temperature time series (e.g., Wald-Wolfowitz serial correlation test, Spearman and Mann-Kendall trend tests). Secondly, based on previous results, a selection of the highest quality time series was carried out. Aiming at identifying temperature extremes, we then proceed to the isolation of months with temperature values above or below pre-selected thresholds based on the empirical distribution of each time series. In particular, thresholds are based on percentiles specifically computed for each individual temperature record (data adaptive) and not on fixed values. As a result, a calendar of extremely high and extremely low monthly mean temperatures is obtained and the large-scale atmospheric conditions during each extreme are analyzed. Several atmospheric fields are considered in this study (e.g., 2-m maximum and minimum air temperature, sea level pressure, geopotential height, zonal and meridional wind components, vorticity, relative humidity) at different isobaric levels. Results show remarkably different synoptic conditions for temperature extremes in different parts of Western Europe, highlighting the different dynamical mechanisms underlying their

  5. High-pressure (vapor + liquid) equilibria in the (nitrogen + n-heptane) system

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Sanchez, Fernando [Laboratorio de Termodinamica, Programa de Ingenieria Molecular, Instituto Mexicano del Petroleo, Eje Central Lazaro Cardenas 152, 07730 Mexico, D.F. (Mexico)]. E-mail:; Eliosa-Jimenez, Gaudencio [Laboratorio de Termodinamica, Programa de Ingenieria Molecular, Instituto Mexicano del Petroleo, Eje Central Lazaro Cardenas 152, 07730 Mexico, D.F. (Mexico); Silva-Oliver, Guadalupe [Laboratorio de Termodinamica, Programa de Ingenieria Molecular, Instituto Mexicano del Petroleo, Eje Central Lazaro Cardenas 152, 07730 Mexico, D.F. (Mexico); Godinez-Silva, Armando [Laboratorio de Termodinamica, Programa de Ingenieria Molecular, Instituto Mexicano del Petroleo, Eje Central Lazaro Cardenas 152, 07730 Mexico, D.F. (Mexico)


    In this work, new (vapor + liquid) equilibrium data for the (N{sub 2} + n-heptane) system were experimentally measured over a wide temperature range from (313.6 to 523.7) K and pressures up to 50 MPa. A static-analytic apparatus with visual sapphire windows and pneumatic capillary samplers was used in the experimental measurements. Equilibrium phase compositions and (vapor + liquid) equilibrium ratios are reported. The new results were compared with those reported by other authors. The comparison showed that the pressure-composition data reported in this work are less scattered than those determined by others. Hence, the results demonstrate the reliability of the experimental apparatus at high temperatures and pressures. The experimental data were represented with the PR and PC-SAFT equations of state by using one-fluid mixing rules and a single temperature independent interaction parameter. Results of the representation showed that the PC-SAFT equation was superior to the PR equation in correlating the experimental data of the (N{sub 2} + n-heptane) system.

  6. Ternary liquid-liquid equilibria for the phenolic compounds extraction from artificial textile industrial waste (United States)

    Fardhyanti, Dewi Selvia; Prasetiawan, Haniif; Hermawan, Sari, Lelita Sakina


    Liquid waste in textile industry contains large amounts of dyes and chemicals which are capable of harming the environment and human health. It is due to liquid waste characteristics which have high BOD, COD, temperature, dissolved and suspended solid. One of chemical compound which might be harmful for environment when disposed in high concentration is phenol. Currently, Phenol compound in textile industrial waste has reached 10 ppm meanwhile maximum allowable phenol concentration is not more than 0.2 ppm. Otherwise, Phenol also has economic value as feedstock of plastic, pharmaceutical and cosmetic industry. Furthermore, suitable method to separate phenol from waste water is needed. In this research, liquid - liquid extraction method was used with extraction time for 70 minutes. Waste water sample was then separated into two layers which are extract and raffinate. Thereafter, extract and raffinate were then tested by using UV-Vis Spectrophotometer to obtained liquid - liquid equilibrium data. Aim of this research is to study the effect of temperature, stirring speed and type of solvent to obtain distribution coefficient (Kd), phenol yield and correlation of Three-Suffix Margules model for the liquid - liquid extraction data equilibrium. The highest extraction yield at 80.43 % was found by using 70% methanol as solvent at extraction temperature 50 °C with stirring speed 300 rpm, coefficient distribution was found 216.334. From this research it can be concluded that Three-Suffix Margules Model is suitable to predict liquid - liquid equilibrium data for phenol system.

  7. Effect of land albedo, CO2, orography, and oceanic heat transport on extreme climates

    Directory of Open Access Journals (Sweden)

    V. Romanova


    Full Text Available Using an atmospheric general circulation model of intermediate complexity coupled to a sea ice – slab ocean model, we perform a number of sensitivity experiments under present-day orbital conditions and geographical distribution to assess the possibility that land albedo, atmospheric CO2, orography and oceanic heat transport may cause an ice-covered Earth. Changing only one boundary or initial condition, the model produces solutions with at least some ice-free oceans in the low latitudes. Using some combination of these forcing parameters, a full Earth's glaciation is obtained. We find that the most significant factor leading to an ice-covered Earth is the high land albedo in combination with initial temperatures set equal to the freezing point. Oceanic heat transport and orography play only a minor role for the climate state. Extremely low concentrations of CO2 also appear to be insufficient to provoke a runaway ice-albedo feedback, but the strong deviations in surface air temperatures in the Northern Hemisphere point to the existence of a strong nonlinearity in the system. Finally, we argue that the initial condition determines whether the system can go into a completely ice covered state, indicating multiple equilibria, a feature known from simple energy balance models.

  8. Conformational Dynamics and Binding Free Energies of Inhibitors of BACE-1: From the Perspective of Protonation Equilibria.

    Directory of Open Access Journals (Sweden)

    M Olivia Kim


    Full Text Available BACE-1 is the β-secretase responsible for the initial amyloidogenesis in Alzheimer's disease, catalyzing hydrolytic cleavage of substrate in a pH-sensitive manner. The catalytic mechanism of BACE-1 requires water-mediated proton transfer from aspartyl dyad to the substrate, as well as structural flexibility in the flap region. Thus, the coupling of protonation and conformational equilibria is essential to a full in silico characterization of BACE-1. In this work, we perform constant pH replica exchange molecular dynamics simulations on both apo BACE-1 and five BACE-1-inhibitor complexes to examine the effect of pH on dynamics and inhibitor binding properties of BACE-1. In our simulations, we find that solution pH controls the conformational flexibility of apo BACE-1, whereas bound inhibitors largely limit the motions of the holo enzyme at all levels of pH. The microscopic pKa values of titratable residues in BACE-1 including its aspartyl dyad are computed and compared between apo and inhibitor-bound states. Changes in protonation between the apo and holo forms suggest a thermodynamic linkage between binding of inhibitors and protons localized at the dyad. Utilizing our recently developed computational protocol applying the binding polynomial formalism to the constant pH molecular dynamics (CpHMD framework, we are able to obtain the pH-dependent binding free energy profiles for various BACE-1-inhibitor complexes. Our results highlight the importance of correctly addressing the binding-induced protonation changes in protein-ligand systems where binding accompanies a net proton transfer. This work comprises the first application of our CpHMD-based free energy computational method to protein-ligand complexes and illustrates the value of CpHMD as an all-purpose tool for obtaining pH-dependent dynamics and binding free energies of biological systems.

  9. The “maturation” of milk for Parmigiano- Reggiano cheesemaking: effects on mineral equilibria and technological properties

    Directory of Open Access Journals (Sweden)

    P. Mariani


    Full Text Available The “maturation” of milk for Parmigiano-Reggiano cheese is characterised by natural creaming process: the full cream milk is placed in large flat vats, for about 10-12 hours, to obtain the gravity separation of milk fat. The modifications of mineral equilibria and technological properties of milk during the “maturation” phase, were studied. To this aim 24 full cream (FC milk samples and the corresponding partially skimmed (PS milk, by natural creaming, were analysed. PS milk evidenced higher values of both colloidal Ca/casein (+4.28%; P£0.01 and colloidal P/casein (+4.02%; P£0.01 ratios than FC milk. An increase of pH (+0.028; P£0.01 and titratable acidity (+0.03 °SH/50ml; P£0.01 was observed during the milk “maturation”. The PS milk was characterised by a higher milk clotting time (r (+7.91%; P£0.01 and a lower curd firmness (a30 (−16.75%; P£0.01 than FC milk. Concerning rheological properties, PS milk curd was characterised by higher values of both resistance to compression (+14.82%; P£0.01 and resistance to cut (+15.12%; P£0.01 than FC milk. The variations of milk characteristics observed in PS milk seems to indicate a structural modification of the native micelle during the “maturation” phase; this feature contributed to variations of rennet-coagulation and rheological properties observed in PS milk.

  10. Atomistic simulations of the effects of polyglutamine chain length and solvent quality on conformational equilibria and spontaneous homodimerization. (United States)

    Vitalis, Andreas; Wang, Xiaoling; Pappu, Rohit V


    Aggregation of expanded polyglutamine tracts is associated with nine different neurodegenerative diseases, including Huntington's disease. Experiments and computer simulations have demonstrated that monomeric forms of polyglutamine molecules sample heterogeneous sets of collapsed structures in water. The current work focuses on a mechanistic characterization of polyglutamine homodimerization as a function of chain length and temperature. These studies were carried out using molecular simulations based on a recently developed continuum solvation model that was designed for studying conformational and binding equilibria of intrinsically disordered molecules such as polyglutamine systems. The main results are as follows: Polyglutamine molecules form disordered, collapsed globules in aqueous solution. These molecules spontaneously associate at conditions approaching those of typical in vitro experiments for chains of length N>/=15. The spontaneity of these homotypic associations increases with increasing chain length and decreases with increasing temperature. Similar and generic driving forces govern both collapse and spontaneous homodimerization of polyglutamine in aqueous milieus. Collapse and dimerization maximize self-interactions and reduce the interface between polyglutamine molecules and the surrounding solvent. Other than these generic considerations, there do not appear to be any specific structural requirements for either chain collapse or chain dimerization; that is, both collapse and dimerization are nonspecific in that disordered globules form disordered dimers. In fact, it is shown that the driving force for intermolecular associations is governed by spontaneous conformational fluctuations within monomeric polyglutamine. These results suggest that polyglutamine aggregation is unlikely to follow a homogeneous nucleation mechanism with the monomer as the critical nucleus. Instead, the results support the formation of disordered, non-beta-sheet-like soluble

  11. Competing turbulent cascades and eddy-wave interactions in shallow water equilibria (United States)

    Weichman, Peter B.


    In recent work, Renaud, Venaille, and Bouchet (RVB) [Renaud et al., J. Stat. Phys. 163, 784 (2016), 10.1007/s10955-016-1496-x] revisit the equilibrium statistical mechanics theory of the shallow water equations, within a microcanonical approach, focusing on a more careful treatment of the energy partition between inertial gravity wave and eddy motions in the equilibrium state and deriving joint probability distributions for the corresponding dynamical degrees of freedom. The authors derive a Liouville theorem that determines the underlying phase space statistical measure, but then, through some physical arguments, actually compute the equilibrium statistics using a measure that violates this theorem, choosing equal volume vs equal area fluid parcels. Here, using a more convenient, but essentially equivalent, grand canonical approach, the full statistical theory consistent with the Liouville theorem is derived. The results reveal several significant differences from the previous results (1) The microscale wave motions lead to a strongly fluctuating thermodynamics, including long-range correlations, in contrast to the mean-field-like behavior found by RVB. The final effective model is equivalent to that of an elastic membrane with a nonlinear wave-renormalized surface tension. (2) Even when a mean-field approximation is made, a rather more complex joint probability distribution is revealed. Alternative physical arguments fully support the consistency of the results. Of course, the true fluid final steady state relies on dissipative processes not included in the shallow water equations, such as wave breaking and viscous effects, but it is argued that the current theory provides a more mathematically consistent starting point for future work aimed at assessing their impacts.

  12. Outcomes for Extremely Premature Infants (United States)

    Glass, Hannah C.; Costarino, Andrew T.; Stayer, Stephen A.; Brett, Claire; Cladis, Franklyn; Davis, Peter J.


    Premature birth is a significant cause of infant and child morbidity and mortality. In the United States, the premature birth rate, which had steadily increased during the 1990s and early 2000s, has decreased annually for four years and is now approximately 11.5%. Human viability, defined as gestational age at which the chance of survival is 50%, is currently approximately 23–24 weeks in developed countries. Infant girls, on average, have better outcomes than infant boys. A relatively uncomplicated course in the intensive care nursery for an extremely premature infant results in a discharge date close to the prenatal EDC. Despite technological advances and efforts of child health experts during the last generation, the extremely premature infant (less than 28 weeks gestation) and extremely low birth weight infant (ELBW) (premature labor improved neonatal mortality and morbidity in the late 1990s. The recognition that chronic postnatal administration of steroids to infants should be avoided may have improved outcomes in the early 2000s. Evidence from recent trials attempting to define the appropriate target for oxygen saturation in preterm infants suggests arterial oxygen saturation between 91–95% (compared to 85–89%) avoids excess mortality. However, final analyses of data from these trials have not been published, so definitive recommendations are still pending The development of neonatal neurocognitive care visits may improve neurocognitive outcomes in this high-risk group. Long-term follow up to detect and address developmental, learning, behavioral, and social problems is critical for children born at these early gestational ages. The striking similarities in response to extreme prematurity in the lung and brain imply that agents and techniques that benefit one organ are likely to also benefit the other. Finally, since therapy and supportive care continue to change, the outcomes of ELBW infants are ever evolving. Efforts to minimize injury, preserve

  13. Extreme Events: The Indian Experience (United States)

    Murty, K. S.


    The geographical situation of India is such that it experiences varied types of climate in different parts of the country and invariably the natural events, extreme and normal, would affect such areas that are prone to them. Cyclones hit the eastern coast, while floods affect mostly northern India, while earthquakes hit any part of the country, particuarly when itbecame evident after the 1967 earthquake of Koyna that the peninsular part toois prone to seismic events. The National Commission on Floods estimated that nearly 40 millionn hectares of land is prone to flooding, which could rise to60 million soon. The cropped area thus affected annually is about 10 millionhectares. On an average 1500 lives are lost during floods annually, while the damage to property could run into billions of dollars. The total loss on account of floods damage to crops is estimated at about Rs 53,000 crores(crore= 100 lakhs), during the period 1953-1998. The other extreme natural event is drought which affects large parts of the country, except the northeast. Both floods and droughts can hit different parts of the country during the same period. The 2001 earthquake that hit Gujarat is perhaps the severest and studies on that event are still in progress. The 2004 tsunami which hit large parts of southeast Asia did not spare India. Its southern coast was battered and many lives were lost. In fact some geogrphic landmarks were lost, while some of the cities have suffered a shift in their position. It was estimated that about 1.2 billion dollars were required ro meet the rehabilitation and relief measures. The seismic zone map of India thus had to be revised more often than before. Apart from these, extreme rainfall has also caused floods in urban areas as in Mumbai in 2005, but this was mostly because of lack of proper drainage system and the existing system proved ineffective. Human hand in such cases is evident. There are systems working to forecast floods, cyclones, and droughts, though

  14. Promoting Exit from Violent Extremism

    DEFF Research Database (Denmark)

    Dalgaard-Nielsen, Anja


    a perspective on how these natural sources of doubt might best be brought to bear in connection with an exit program by drawing on social psychology and research into persuasion and attitude change. It is argued that an external intervention should stay close to the potential exiter’s own doubt, make......A number of Western countries are currently adding exit programs targeting militant Islamists to their counterterrorism efforts. Drawing on research into voluntary exit from violent extremism, this article identifies themes and issues that seem to cause doubt, leading to exit. It then provides...

  15. Communication path for extreme environments (United States)

    Jorgensen, Charles C. (Inventor); Betts, Bradley J. (Inventor)


    Methods and systems for using one or more radio frequency identification devices (RFIDs), or other suitable signal transmitters and/or receivers, to provide a sensor information communication path, to provide location and/or spatial orientation information for an emergency service worker (ESW), to provide an ESW escape route, to indicate a direction from an ESW to an ES appliance, to provide updated information on a region or structure that presents an extreme environment (fire, hazardous fluid leak, underwater, nuclear, etc.) in which an ESW works, and to provide accumulated thermal load or thermal breakdown information on one or more locations in the region.

  16. Gravity and Extreme Magnetism SMEX (United States)


    The Gravity and Extreme Magnetism SMEX mission will be the first mission to catalogue the X-ray polarisation of many astrophysical objects including black-holes and pulsars. This first of its kind mission is enabled by the novel use of a time projection chamber as an X-ray polarimeter. The detector has been developed over the last 5 years, with the current effort charged toward a demonstration of it's technical readiness to be at level 6 prior to the preliminary design review. This talk will describe the design GEMS polarimeter and the results to date from the engineering test unit.

  17. Statistical analysis on extreme wave height

    Digital Repository Service at National Institute of Oceanography (India)

    Teena, N.V.; SanilKumar, V.; Sudheesh, K.; Sajeev, R.

    The classical extreme value theory based on generalized extreme value (GEV) distribution and generalized Pareto distribution (GPD) is applied to the wave height estimate based on wave hindcast data covering a period of 31 years for a location...

  18. Extreme Biocatalyst Culture Collection for Unique Microorganisms

    National Research Council Canada - National Science Library

    Jain, Mahendra


    To develop an Extreme Biocatalyst Culture Collection (EBCC) as a resource center to supply pure, viable and authentic cultures of extremophilic Inicroorganisms which are non-conventional, novel, or of extreme nature...

  19. Climate change & extreme weather vulnerability assessment framework. (United States)


    The Federal Highway Administrations (FHWAs) Climate Change and Extreme Weather Vulnerability : Assessment Framework is a guide for transportation agencies interested in assessing their vulnerability : to climate change and extreme weather event...

  20. Variational analysis critical extremals and Sturmian extensions

    CERN Document Server

    Morse, Marston


    This text presents extended separation, comparison, and oscillation theorems that replace classical analysis. Its analysis of related quadratic functionals shows how critical extremals can substitute for minimizing extremals. 1973 edition.